Cylindrical battery monomer, battery device and power utilization device

Abstract

The present application relates to the field of batteries, and discloses a cylindrical battery cell (100), a battery device (1000) and a power utilization device, the cylindrical battery cell (100) comprising a housing (20) and an electrode assembly (10). The shell (20) is provided with a pressure relief part (22111). The electrode assembly (10) is of a winding structure and comprises two pole pieces (1). At least one pole piece (1) comprises a pole piece main body (11) and a pole lug (12) which are arranged along a first direction (Z). The tab (12) comprises a plurality of tab winding parts (121) which are distributed along the winding direction of the electrode assembly, and a first cut-off groove (102) which is wound for at least one circle is formed between every two adjacent tab winding parts (121). And the first cut-off groove (102) penetrates through the end surface, far away from the pole piece main body (11), of the pole lug (12). Therefore, the directional pressure relief efficiency can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a cylindrical battery monomer, a battery device and a power utilization device. BACKGROUND

[0002] From the development of market situation, the application of the battery device is more and more extensive. The battery device is not only applied to the energy storage system such as hydroelectric power station, thermal power station, wind power station and solar power station, but also widely applied to electric bicycles, electric motorcycles, electric vehicles and other electric vehicles, military equipment, aerospace and other fields. With the continuous expansion of the application field of the battery device, the market demand is also increasing. And the capacity of the battery device is getting larger and larger, and the performance requirement of the battery device is getting higher and higher.

[0003] In the related art, the battery device usually includes one or more battery monomers. In the use process of the battery monomer, when the battery monomer appears external short circuit, overcharge, needle puncture, flat plate impact and the like, heat runaway is easily caused.

[0004] For the cylindrical battery monomer, in some cases, the tab of the battery monomer generally has a relatively large constraint function itself, so that the tab will have a strong hindering effect on the high-temperature and high-pressure medium. In this way, the rate of the high-temperature and high-pressure medium generated by the cylindrical battery monomer during heat runaway spreading towards the pressure relief mechanism is relatively low, so that the efficiency of the cylindrical battery monomer through the pressure relief mechanism for directional pressure relief is relatively low.

[0005] The above statements are only used to provide background technical information related to the present application, and do not necessarily constitute the prior art. CONTENT OF THE UTILITY MODEL

[0006] In view of the above problems, the purpose of the embodiments of the present application is to provide a cylindrical battery monomer, a battery device and a power utilization device, which can improve the technical problem of low directional pressure relief efficiency of the cylindrical battery monomer.

[0007] The technical solution adopted by the embodiments of the present application is:

[0008] In a first aspect, the embodiments of the present application provide a cylindrical battery monomer, comprising:

[0009] The shell is provided with a pressure relief part at least at one end in the first direction, and the pressure relief part is configured to be at least partially opened when pressure relief;

[0010] The electrode assembly is at least partially arranged in the shell; the electrode assembly is in a winding structure and includes two tabs with opposite polarities; at least one tab includes a tab body arranged in a first direction and a tab lug, the tab body is coated with an active material layer, and at least part of the tab lug is not coated with the active material layer; in a projection plane perpendicular to the first direction, at least part of the orthogonal projection of the tab lug is located in the orthogonal projection of the pressure relief portion;

[0011] The tab includes a plurality of tab winding portions distributed along the winding direction of the electrode assembly, a first cut-off groove is arranged between any two adjacent tab winding portions, the first cut-off groove penetrates the end face of the tab away from the tab body, and the first cut-off groove is wound at least one turn along the winding direction of the electrode assembly.

[0012] The cylindrical battery cell provided by the embodiments of the present application has the following advantages. The tab of the electrode assembly includes a plurality of tab winding portions distributed along the winding direction of the electrode assembly. Along the winding direction of the electrode assembly, a first cut-off groove is arranged between any two adjacent tab winding portions. The first cut-off groove penetrates the end face of the tab away from the tab body and is wound at least one turn along the winding direction. The plurality of tab winding portions are disconnected through the first cut-off groove. Under the action of the first cut-off groove wound at least one turn, the mutual binding action between the plurality of tab winding portions is weakened, and the mutual binding action between the plurality of tab winding portions of the tab and the binding action between the tab winding portion and the tab ring portion are also weakened. The shell is provided with a pressure relief portion at least one end along the first direction, and the pressure relief portion is configured to be at least partially opened to form an exhaust passage when pressure relief. In the process of thermal runaway of the cylindrical battery cell, the binding action between the plurality of tab winding portions is easily broken under the action of air pressure, and the mutual binding action between the plurality of tab winding portions and the binding action between the tab winding portion and the tab ring portion are also easily broken. Therefore, the tab is easily loosened in the direction of the pressure relief portion under the action of air pressure, and even discharged to the outside of the shell through the pressure relief portion. In this way, the hindering effect of the tab on the high-temperature and high-pressure medium can be reduced, the high-temperature and high-pressure medium is easily spread toward the pressure relief portion, and discharged to the outside of the shell through the exhaust passage formed by the opening of the pressure relief portion. In this way, the discharge rate and efficiency of the high-temperature and high-pressure medium can be improved, so that the cylindrical battery cell can realize efficient directional pressure relief, thereby improving the reliability of the cylindrical battery cell.

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

[0014] In this way, when the cylindrical battery cell is in a thermal runaway process, the binding effect between the first tab winding part and the other tab winding parts is easily broken under the action of air pressure, so that at least part of the tab is easily loosened under the action of air pressure, and even discharged to the outside of the shell through the exhaust passage formed by opening the pressure relief part. In this way, the tab is easily loosened and even discharged, which helps the cylindrical battery cell to achieve efficient directional pressure relief effect.

[0015] In some embodiments, in a projection plane perpendicular to the first direction, the orthographic projection of the first tab winding part is located within the orthographic projection of the pressure relief part.

[0016] In this way, during the pressure relief process of the cylindrical battery cell, the tab 1 is easily loosened under the action of air pressure, and even discharged to the outside of the shell through the exhaust passage formed by opening the pressure relief part. In this way, it helps to improve the directional pressure relief effect of the cylindrical battery cell.

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

[0018] Alternatively, the tab includes a first cut-off groove, and in a projection plane perpendicular to the first direction, at least part of the first groove bottom surface of the first cut-off groove is located within the orthographic projection of the pressure relief part.

[0019] By adopting the above technical solutions, the tab is easily loosened under the action of air pressure and discharged to the outside of the shell through the exhaust passage, thereby helping the cylindrical battery cell to achieve efficient directional pressure relief effect and improving the problem of low directional pressure relief efficiency of the cylindrical battery cell.

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

[0021] By adopting the technical scheme, when the cylindrical battery cell is in a thermal runaway process, the first tab winding part can be discharged to the outside of the shell through the exhaust passage under the action of air pressure, so that the effect of the tab on the high-temperature and high-pressure medium can be reduced. In this process, on the one hand, the high-temperature and high-pressure medium generated in the cylindrical battery cell can be discharged to the outside of the shell together with the first tab winding part, and on the other hand, the region of the tab opposite to the pressure relief part forms a larger passage, and the passage gradually increases with the discharge of the first tab winding part, so that the high-temperature and high-pressure medium can be discharged. In this way, the discharge efficiency of the high-temperature and high-pressure medium can be improved, so that the cylindrical battery cell can realize efficient directional pressure relief, thereby helping to improve the reliability of the cylindrical battery cell.

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

[0023] In this way, when the pressure value inside the shell reaches the threshold value, at least part of the first tab winding part close to the winding start end can be discharged to the outside of the shell through the exhaust passage, so that the first tab winding part can be loosened and discharged through the exhaust passage under the action of air pressure, thereby helping to improve the directional pressure relief efficiency of the cylindrical battery cell.

[0024] In some embodiments, the tab is provided with a center hole extending along the first direction, and each tab winding part is arranged around the outer periphery of the center hole. In a projection plane perpendicular to the first direction, the orthographic projection of the center hole is located in the orthographic projection of the pressure relief part.

[0025] In this way, the center hole is arranged to facilitate the loosening of the tab under the action of air pressure and the discharge of the tab to the outside of the shell, thereby facilitating exhaust and efficient directional pressure relief.

[0026] In this way, during the thermal runaway process of the cylindrical battery cell, at least part of the tab adjacent to the center hole can be gradually discharged to the outside of the shell through the exhaust passage formed by the opening of the pressure relief part, 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 center hole is D2, and D2 / D1∈[5%, 25%].

[0028] In this way, the center hole has a larger hole diameter, so that during the thermal runaway process of the cylindrical battery cell, the high-temperature and high-pressure medium inside the cylindrical battery cell can be discharged to the pressure relief part through the center hole to achieve efficient directional pressure relief.

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

[0030] In this way, the discharge rate and efficiency of the high-temperature and high-pressure medium can be improved, so that the cylindrical battery cell can achieve efficient directional pressure relief effect, thereby helping to improve the reliability of the cylindrical battery cell.

[0031] In some embodiments, the two pole pieces each include a pole piece body and a tab, and the tabs of the two pole pieces are respectively arranged at two ends of the electrode assembly along the first direction, and the tab of each pole piece includes a plurality of tab winding portions.

[0032] In this way, the at least part of the electrode assembly facing the pressure relief portion can be discharged to the outside of the shell through the exhaust passage under the action of the gas pressure, so as to achieve an efficient directional pressure relief effect, thereby helping to improve the reliability of the cylindrical battery cell.

[0033] In some embodiments, the two pole pieces include a positive pole piece and a negative pole piece, and the tab of the positive pole piece and / or the tab of the negative pole piece is not coated with an active material layer.

[0034] By not coating the tab of at least one of the positive pole piece and the negative pole piece with an active material layer, only the tab is cut during the process of cutting the tab to form the tab winding portion and the first cut-off groove, so that the part of the pole piece where the active material layer is arranged is not cut, so that the first cut-off groove is formed in the part of the pole piece where the active material layer is not arranged. This can to some extent guarantee the performance of the active material layer and to some extent guarantee the performance of the electrode assembly, thereby improving the charge and discharge performance of the cylindrical battery cell.

[0035] In some embodiments, the electrode assembly has a winding axis parallel to the first direction, and at least one tab winding portion is provided with a bending segment at one end in the first direction.

[0036] The bending segment includes a first bending portion bent towards the winding axis relative to the pole piece body, and / or the bending segment includes a second bending portion bent away from the winding axis relative to the pole piece body.

[0037] In this way, the end region of the tab winding portion away from the pole piece body in the first direction can be bent to form a relatively dense stacking layer. In this way, on the one hand, the tab layer of the tab winding portion and the gap between the tab layers can be reduced, facilitating the welding of the tab winding portion and the current collecting member. On the other hand, the pole piece has a strong binding effect under the bending of the tab, thereby improving the structural integrity and performance of the electrode assembly.

[0038] In some embodiments, each tab winding portion is provided with a bending segment at one end in the first direction.

[0039] In this way, the end region of the tab away from the tab body in the first direction can be better bent to form a relatively dense stacking layer.

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

[0041] Among the plurality of tab winding portions, the innermost tab winding portion is provided with a first notch groove, the first notch groove penetrates the winding start end and the end face of the tab winding portion away from the tab body along the winding direction of the electrode assembly;

[0042] In the projection plane perpendicular to the first direction, the orthographic projection of the third groove bottom surface of the first notch groove is located in the orthographic projection of the pressure relief portion.

[0043] By locating the orthographic projection of the third groove bottom surface of the first notch groove in the orthographic projection of the pressure relief portion in the projection plane perpendicular to the first direction, the tab winding portion (which can be the first tab winding portion) formed with the first notch groove is also arranged in the first direction opposite to the pressure relief portion. In this way, the restraint of the tab winding portion formed with the first notch groove can be reduced, which facilitates the tab winding portion formed with the first notch groove to be discharged to the outside of the shell through the pressure relief portion during thermal runaway, thereby facilitating to improve the directional pressure relief efficiency of the cylindrical battery cell.

[0044] In some embodiments, the cylindrical battery cell further comprises a current collecting member, at least part of the current collecting member is arranged in the shell;

[0045] The tab winding portion has a winding start segment at one end of the first notch groove close to the tab body, the third groove bottom surface is the end face of the winding start segment away from the tab body, and the current collecting member is welded to the part of the tab winding portion beyond the third groove bottom surface in the direction away from the tab body, and is not welded to the winding start segment.

[0046] By welding the current collecting member to the part of the tab winding portion beyond the third groove bottom surface, and not welding to the winding start segment, the restraint of the part of the tab winding portion formed with the first notch groove is lower, which facilitates the tab winding portion formed with the first notch groove to be discharged through the pressure relief portion under the action of air pressure during thermal runaway of the cylindrical battery cell, thereby facilitating to improve the directional pressure relief efficiency of the cylindrical battery cell.

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

[0048] Among the plurality of tab winding portions, the outermost tab winding portion is provided with a second notch groove, the second notch groove penetrates the winding end and the end face of the tab away from the tab body along the winding direction of the electrode assembly.

[0049] In this way, the second notch groove can form a passage to facilitate the exhaust. Moreover, the binding effect of the tab winding part formed with the second notch groove is reduced, and the tab winding part formed with the second notch groove is loose or even ejected from the pressure relief part during the thermal runaway process. Therefore, the directional pressure relief efficiency of the cylindrical battery cell can be improved.

[0050] In some embodiments, the cylindrical battery cell further comprises a current collecting member, at least a part of the current collecting member is arranged in the shell;

[0051] The tab winding part has a winding end segment located at one end of the second notch groove close to the tab main body, the fourth groove bottom surface of the second notch groove is an end surface of the winding end segment away from the tab main body, the current collecting member is welded to a part of the tab winding part beyond the fourth groove bottom surface in a direction away from the tab main body, and the part is not welded to the winding end segment.

[0052] By welding the part of the tab winding part beyond the fourth groove bottom surface to the current collecting member and not welding the part to the winding end segment, the binding effect of the part of the tab winding part formed with the second notch groove is reduced, and the tab winding part formed with the second notch groove is discharged through the pressure relief part under the action of air pressure during the thermal runaway process of the cylindrical battery cell, thereby improving the directional pressure relief efficiency of the cylindrical battery cell.

[0053] In some embodiments, the at least one tab winding part comprises a plurality of sections distributed along the winding direction of the electrode assembly, and at least one second cut groove is arranged between any two adjacent sections in the tab winding part along the winding direction of the electrode assembly.

[0054] In the projection plane perpendicular to the first direction, the orthographic projection of the second groove bottom surface of the at least one second cut groove is located in the orthographic projection of the pressure relief part.

[0055] In this way, the self-binding effect of the part of the at least one tab winding part opposite to the pressure relief part is weakened under the action of the second cut groove, so that the self-binding effect of the at least one tab winding part is also weakened. In this way, the cylindrical battery cell can achieve efficient directional pressure relief effect, improve the problem of low directional pressure relief efficiency of the cylindrical battery cell, and improve the reliability of the cylindrical battery cell.

[0056] In some embodiments, the plurality of tab winding parts comprises a first tab winding part and a second tab winding part adjacent to each other, and the second tab winding part is arranged outside the first tab winding part.

[0057] The first tab winding part comprises a plurality of sections, and in the projection plane perpendicular to the first direction, the orthographic projection of the second groove bottom surface of the at least one second cut groove in the first tab winding part is located in the orthographic projection of the pressure relief part.

[0058] By adopting the technical scheme, the self-binding effect of the first tab winding part is weakened under the arrangement of the second cut-off groove, so that when the pressure value inside the shell reaches a threshold value, the first tab winding part is facilitated to be discharged to the outside of the shell through the pressure relief part, so that the cylindrical battery monomer realizes efficient directional pressure relief effect.

[0059] In some embodiments, the plurality of tab winding parts includes a first tab winding part and a second tab winding part adjacent to the first tab winding part, and the second tab winding part is arranged outside the first tab winding part.

[0060] The second tab winding part includes a plurality of segments, and among the plurality of segments of the second tab winding part, the segment closest to the first tab winding part is wound at least three times.

[0061] In this way, the segment closest to the first cut-off groove in the second tab winding part can better wrap the first cut-off groove, and the problem of tab collapse caused by the arrangement of the first cut-off groove can be improved, so that the overall binding effect of the tab can be improved, and the electrode assembly has higher performance.

[0062] In some embodiments, among the plurality of segments of the second tab winding part, the segment closest to the first tab winding part is wound ≤8 times.

[0063] In this way, on the one hand, the segment closest to the first cut-off groove in the second tab winding part can better wrap the first cut-off groove, and the problem of tab collapse caused by the arrangement of the first cut-off groove can be improved, and on the other hand, the second cut-off groove can also be formed in the second tab winding part to help improve the directional pressure relief efficiency of the cylindrical battery monomer.

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

[0065] In this way, the insulating layer is arranged on the positive electrode tab 1a, so that the short circuit problem between the positive electrode tab and the negative electrode tab can be effectively improved.

[0066] In some embodiments, at least one tab winding part includes a transition connection part and a segment, and the tab body, the transition connection part and the segment are arranged in sequence along the first direction, and in the tab winding part, the transition connection part and the two segments adjacent to the winding direction of the electrode assembly form a second cut-off groove, and the second groove bottom surface of the second cut-off groove is formed on the side edge of the transition connection part for connecting the segments.

[0067] The transition connection part is connected between the pole piece body and the cut piece. On the one hand, the pole piece body and the cut piece are arranged at intervals along the first direction, and the pole piece body and the second cut-off groove are arranged at intervals along the first direction. In this way, in the process of cutting the tab winding part to form the second cut-off groove and the cut piece, the pole piece body can be avoided to a certain extent to avoid being cut. Moreover, the problem that the second groove bottom surface of the second cut-off groove is formed on one side edge of the pole piece body, causing the pole piece body to be easily torn and damaged, can be solved. On the other hand, the transition connection part can block the cut piece to block the cut piece and the main body part of the electrode assembly, so that the problem of internal short circuit caused by the insertion of the bent cut piece into the main body part can be improved, and the risk of short circuit can be reduced.

[0068] In some embodiments, the size of the side edge of each cut piece for connecting the transition connection part in the winding direction of the electrode assembly is H1, the size of the transition connection part and the cut piece in the first direction is H2, and 0.01≤H2 / H1≤0.3.

[0069] In this way, the cut piece has a larger size in the winding direction, which facilitates the winding of the cut piece and ensures the structural integrity of the electrode assembly to a certain extent, thereby ensuring the charge and discharge performance of the cylindrical battery cell to a certain extent.

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

[0071] In this way, on the basis that the tab winding part can form the second cut-off groove, the transition connection part has a suitable width in the first direction to block the cut piece, and the problem of the insertion of the bent cut piece into the main body part can be improved.

[0072] In some embodiments, at least one pole piece has a winding starting end and a winding ending end at two ends in the winding direction of the electrode assembly, and among the plurality of tab winding parts, the winding ending end is formed in the outermost tab winding part in the winding direction of the electrode assembly.

[0073] Among the plurality of tab winding parts, the outermost tab winding part includes a plurality of cut pieces in the winding direction of the electrode assembly, and the cut piece closest to the winding ending end is wound at least one turn.

[0074] By winding the cut piece closest to the winding ending end at least one turn, the cut piece closest to the winding ending end can better wrap the other cut pieces, which can improve the problem of internal short circuit caused by the everted cut piece inserted into the main body part, thereby reducing the risk of short circuit.

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

[0076] By forming a plurality of second cutting-off grooves on the tab winding part, the tab winding part can achieve a larger cutting-off ratio, so that the part of the tab winding part with the second cutting-off groove can be discharged through the pressure relief part during the thermal runaway process, achieving a higher directional pressure relief effect. Furthermore, on this basis, the accumulation layer formed by bending the part of the tab winding part with the second cutting-off groove will not be too weak, and can effectively block the laser generated during welding, thereby achieving a protection effect on the separator.

[0077] In some embodiments, in the first direction, the size of the tab along the winding direction of the electrode assembly decreases in the direction away from the tab body.

[0078] By gradually reducing the size of the tab along the winding direction in the first direction away from the tab body, the restraining effect of the accumulation layer formed by bending the end region of the tab away from the tab body is reduced, thereby facilitating the loosening of the part of the tab with the second cutting-off groove during the thermal runaway process and discharging through the pressure relief part. Furthermore, under the arrangement of the first cutting-off groove, at least one tab winding part can easily loosen from other tab winding parts under the action of air pressure or even discharge through the pressure relief part. Based on this, the directional pressure relief efficiency is improved.

[0079] In some embodiments, the electrode assembly has a winding axis parallel to the first direction, and at least one tab is provided with a bending segment at one end in the first direction;

[0080] The bending segment includes a first bending part bent in the direction close to the winding axis relative to the tab body, and / or the bending part includes a second bending part bent in the direction away from the winding axis relative to the tab body.

[0081] In this way, the end region of the tab away from the tab body in the first direction can be bent to form a relatively dense accumulation layer, so that the end region of the tab away from the tab body in the first direction can form an accumulation layer.

[0082] In some embodiments, each tab is provided with a bending end at one end in the first direction.

[0083] In this way, each tab of the tab is bent, so that the end region of the tab away from the tab body in the first direction can be bent to form an accumulation layer.

[0084] In some embodiments, the first bending part is bent in the radial direction of the electrode assembly; and / or the second bending part is bent in the radial direction of the electrode assembly.

[0085] In this way, the bending segment is bent in the radial direction, so that the tab can be better bent to form an accumulation layer.

[0086] In some embodiments, the bending section comprises at least one first bending part and at least one second bending part, the first bending part and the second bending part are arranged alternately along the first direction.

[0087] In this way, the end region of the tab away from the tab body in the first direction can be bent to form a relatively dense stacking layer.

[0088] In some embodiments, the tab further comprises a tab ring part, the tab ring part is connected between two adjacent tab winding parts along the winding direction of the electrode assembly, and the tab ring part and the two adjacent tab winding parts along the winding direction of the electrode assembly form the first cut-off groove.

[0089] In this way, the tab ring part can block the tab winding part, which can improve the internal short problem caused by the bending of the tab winding part into the body part, thereby reducing the risk of short circuit.

[0090] In some embodiments, the cylindrical battery cell further comprises a current collecting member, at least part of the current collecting member is arranged in the shell; the current collecting member is welded to the tab winding part to form a first welding part; and the current collecting member is not welded to the tab ring part.

[0091] By welding the current collecting member to the tab winding part of the tab and not welding the current collecting member to the tab ring part of the tab, the self-binding effect of the tab ring part is weakened, and the self-binding effect of the tab ring part is also weakened. In this way, the mutual binding effect of the two adjacent tab winding parts is weakened, and the mutual binding effect of the two adjacent tab winding parts is also weakened. Thus, when the pressure value inside the shell reaches a threshold value, the tab can be loosened under the action of air pressure or even discharged to the outside of the shell through the pressure relief part, which helps the cylindrical battery cell to achieve efficient directional pressure relief effect.

[0092] In some embodiments, in a projection plane perpendicular to the first direction, the two ends of the orthographic projection of the first welding part have a first projection end point and a second projection end point, respectively, the first projection end point is closer to the winding axis parallel to the first direction than the second projection end point, and the area between the first circular arc line passing through the first projection end point and surrounding the winding axis and the second circular arc line passing through the second projection end point and surrounding the winding axis is a first spanning area.

[0093] The at least one tab winding part comprises a plurality of segments distributed along the winding direction of the electrode assembly, and in the tab winding part, any two adjacent segments along the winding direction of the electrode assembly are provided with a second cut-off groove, at least part of the second cut-off groove forms a first group of grooves, and in the first group of grooves, the orthographic projection of the second groove bottom surface of all the second cut-off grooves is located within the first spanning area.

[0094] The current collecting member is welded to the segment to form a first welding portion;

[0095] In the first group of grooves, the number of turns of a single second cut-off groove is ≤3; and / or in the first group of grooves, the number of second cut-off grooves that are diametrically opposite and connected along the radial direction of the electrode assembly is ≤3.

[0096] By adopting the above technical solution, on the basis that the portion of the tab winding portion where the first welding portion is formed is provided with the second cut-off groove, the accumulation layer formed by bending the portion of the tab winding portion where the first welding portion is formed will not be too weak due to the provision of the second cut-off groove, so that the portion of the tab winding portion where the first welding portion is formed can bear the welding penetration of the current collecting member and the tab, thereby improving the problem of laser penetration of the tab to burn the separator during the welding of the current collecting member and the tab, and thus improving the problem of short circuit of the electrode assembly caused by the welding of the current collecting member and the tab, and reducing the risk of short circuit.

[0097] In some embodiments, the cylindrical battery cell further comprises an electrode terminal fixed to the shell, the electrode terminal being welded to the current collecting member to form a second welding portion.

[0098] In this way, the electrical connection between the electrode terminal and the electrode assembly can be achieved.

[0099] In some embodiments, in a projection plane perpendicular to the first direction, the orthographic projection of the second welding portion has a third projection end point and a fourth projection end point at its two ends, respectively, the third projection end point is closer to the winding axis parallel to the first direction than the fourth projection end point, and the area between a third circular arc line passing through the third projection end point and arranged around the winding axis and a fourth circular arc line passing through the fourth projection end point and arranged around the winding axis is a second spanning area.

[0100] The at least one tab winding portion comprises a plurality of segments distributed along the winding direction of the electrode assembly, and in the tab winding portion, a second cut-off groove is provided between any two adjacent segments along the winding direction of the electrode assembly, at least part of the second cut-off grooves form a second group of grooves, and in the second group of grooves, the orthographic projection of the second groove bottom surface of all the second cut-off grooves is located within the second spanning area.

[0101] In the second group of grooves, the number of turns of a single second cut-off groove is ≤3; and / or in the second group of grooves, the number of second cut-off grooves that are diametrically opposite and connected along the radial direction of the electrode assembly is ≤3.

[0102] By adopting the technical scheme, the part where the tab winding part is provided with the second welding part is provided with the second cutting groove, the stacking layer formed by the part where the tab winding part is provided with the second welding part is not too weak due to the second cutting groove, the part where the tab winding part is provided with the second welding part can bear the welding penetration of the current collector member and the electrode terminal, the problem that the laser penetrates the tab and burns the separator during the welding of the current collector member and the electrode terminal can be improved, the problem of short circuit of the electrode assembly caused by the welding of the current collector member and the electrode terminal can be improved, and the risk of short circuit is reduced.

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

[0104] In the plurality of tab winding parts, the innermost tab winding part is provided with a first notch groove along the winding direction of the electrode assembly, the first notch groove penetrates the winding start end and the end face of the tab winding part away from the tab body along the winding direction of the electrode assembly; and the third groove bottom surface of the first notch groove is located in the projection of the pressure relief part in the projection plane perpendicular to the first direction.

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

[0106] Therefore, the problem that the laser penetrates the tab and burns the separator during the welding can be improved, the problem of short circuit of the electrode assembly can be improved, and the risk of short circuit is reduced.

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

[0108] In the plurality of tab winding parts, the outermost tab winding part is provided with a second notch groove along the winding direction of the electrode assembly, the second notch groove penetrates the winding end and the end face of the tab winding part away from the tab body along the winding direction of the electrode assembly;

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

[0110] Therefore, the problem that the laser penetrates the tab and burns the separator during the welding can be improved, the problem of short circuit of the electrode assembly can be improved, and the risk of short circuit is reduced.

[0111] In some embodiments, the two pole pieces each include a pole piece body and a tab, one of the tabs is a first tab and the other is a second tab, the first and second tabs are respectively arranged at two ends of the electrode assembly along the first direction, and the first and second tabs each include a plurality of tab winding portions;

[0112] In the first direction, the two ends of the electrode assembly are each provided with a current collecting member, and the current collecting members at the two ends of the electrode assembly are respectively a first current collecting member and a second current collecting member;

[0113] The shell includes a second end wall, a first end wall, and a side wall, the second end wall and the first end wall are respectively arranged at two ends of the side wall along the first direction, and the electrode terminal is arranged on the second end wall;

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

[0115] By adopting the above technical solution, at least one of the side wall, the first end wall, and the second end wall can serve as one of the current transmission ends of the cylindrical battery monomer, and the electrode terminal serves as the other current transmission end of the cylindrical battery monomer. That is, the electrode terminal and the shell can serve as the two current transmission ends of the cylindrical battery monomer.

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

[0117] In this way, the second current collecting member and the side wall are indirectly electrically connected through the first end wall.

[0118] In some embodiments, in the radial direction of the electrode assembly, the side wall protrudes inward to form a protruding portion; the protruding portion and the electrode assembly are distributed along the first direction, and the second current collecting member is welded to one side of the protruding portion close to or away from the electrode assembly.

[0119] In this way, the second current collecting member is directly electrically connected to the side wall.

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

[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 end of the cylindrical battery monomer.

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

[0123] By adopting the technical scheme, the pressure relief portion and the electrode terminal are arranged at two ends of the shell along the first direction, so that the pressure relief portion and the electrode terminal are conveniently arranged, and the efficiency of assembling multiple cylindrical battery monomers into a group is improved.

[0124] In some embodiments, the current collecting member is provided with an exhaust through hole extending along the first direction, and the exhaust through hole is arranged opposite to the pressure relief portion along the first direction; the current collecting member is provided with multiple guide portions, and the multiple guide portions are arranged at intervals around the outer periphery of the exhaust through hole.

[0125] By adopting the technical scheme, when the pressure value inside the shell reaches the threshold value in the process of thermal runaway of the cylindrical battery monomer, the pressure relief portion can be opened and an exhaust passage is formed under the action of the air pressure, and the guide portion can deform the part of the current collecting member close to the exhaust through hole towards the pressure relief portion and turn it open under the action of the air pressure, so that the aperture of the exhaust through hole gradually increases. In this way, the jellyroll can move towards the pressure relief portion to be sequentially discharged to the outside of the shell through the exhaust through hole and the exhaust passage. In this way, the directional pressure relief efficiency of the cylindrical battery monomer is improved.

[0126] In some embodiments, the guide portion extends to the exhaust through hole, or the guide portion is arranged at intervals with 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.

[0127] In this way, the guide portion can deform the part of the current collecting member close to the exhaust through hole towards the pressure relief portion and turn it open during pressure relief, so as to increase the exhaust through hole and achieve efficient directional pressure relief effect.

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

[0129] By adopting the technical scheme, the guide portion can deform the current collecting member towards the pressure relief portion and turn it open under the action of the air pressure, and the aperture of the exhaust through hole can be increased to a large extent. In this way, during the thermal runaway process of the cylindrical battery monomer, when at least part of the jellyroll is discharged to the outside of the shell through the exhaust passage formed by the opening of the pressure relief portion, the hindering effect of the current collecting member on the jellyroll can be reduced, which helps to improve the efficiency of the jellyroll discharging through the exhaust passage and improve the directional pressure relief efficiency of the cylindrical battery monomer.

[0130] In some embodiments, the guide portion includes a through hole penetrating through the current collecting member along the first direction; and / or, the guide portion includes a second groove not penetrating through the current collecting member along the first direction.

[0131] By adopting the technical scheme, the part of the guiding portion that can guide the current collecting member to be close to the exhaust through hole during thermal runaway can be deformed and turned over towards the pressure relief portion, thereby facilitating the cylinder to improve the directional pressure relief effect of the battery monomer.

[0132] In some embodiments, the electrode assembly is provided with a central hole extending in the first direction, the tab winding portion is arranged around the outer periphery of the central hole, and the exhaust through hole is opposite to the central hole in the first direction and is in communication with the central hole; in a projection plane perpendicular to the first direction, the central hole is located in the projection of the pressure relief portion.

[0133] In this way, when the pressure value inside the shell reaches the threshold value and the pressure relief portion is opened to form the exhaust passage, the central hole, the exhaust through hole and the exhaust passage are sequentially communicated in the first direction, which facilitates exhaust and helps to improve the directional pressure relief efficiency.

[0134] In some embodiments, the shell further comprises a first end wall opposite to the electrode assembly in the first direction, the first end wall is provided with a first groove and a pressure relief portion located in the area surrounded by the first groove, the bottom of the first groove is provided with a weak portion, the pressure relief portion is connected to the weak portion, and at least part of the weak portion is configured to be broken to open the pressure relief portion during pressure relief.

[0135] By adopting the technical scheme, the pressure relief portion is facilitated to open to form the exhaust passage when the pressure value inside the cylindrical battery monomer reaches the threshold value, thereby facilitating at least part of the electrode sheet to be discharged to the outside of the shell through the pressure relief portion under the action of air pressure.

[0136] In some embodiments, the shell further comprises a first wall and a pressure relief mechanism, the first wall is arranged opposite to the electrode assembly in the first direction; the first wall is fixedly connected to the pressure relief mechanism, the pressure relief mechanism is provided with a first groove and a pressure relief portion located in the area surrounded by the first groove, the bottom of the first groove is provided with a weak portion, the pressure relief portion is connected to the weak portion, and at least part of the weak portion is configured to be broken to open the pressure relief portion during pressure relief.

[0137] By adopting the technical scheme, the pressure relief portion is facilitated to open to form the exhaust passage when the pressure value inside the cylindrical battery monomer reaches the threshold value, thereby facilitating the electrode sheet to be discharged to the outside of the shell through the exhaust passage opened by the pressure relief portion under the action of air pressure.

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

[0139] In this way, the exhaust passage opened by the pressure relief portion is also approximately circular, and the electrode assembly is approximately cylindrical, which facilitates the electrode sheet to be discharged through the exhaust passage during thermal runaway, thereby helping to improve the directional pressure relief effect of the battery monomer.

[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 A schematic diagram of a vehicle provided for some embodiments of this application;

[0147] Figure 2 Exploded views of a battery device provided in some embodiments of this application;

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

[0149] Figure 4 for Figure 3 Sectional view along AA;

[0150] Figure 5 for Figure 3 A schematic diagram of the electrode assembly of the provided cylindrical battery cell;

[0151] Figure 6 for Figure 3 A three-dimensional structural diagram of the electrode assembly of the provided cylindrical battery cell before the tabs are bent.

[0152] Figure 7 for Figure 4 enlarged view at B;

[0153] Figure 8 enlarged view at C; Figure 4 enlarged view at D;

[0154] Figure 9 projection view of a pressure relief mechanism and a tab of a cylindrical battery cell provided for some embodiments of the present application;

[0155] Figure 10 unfolding view of a tab of a cylindrical battery cell provided for some embodiments of the present application;

[0156] Figure 11 enlarged view at E; Figure 10 enlarged view at F;

[0157] Figure 12 unfolding view of a tab of a cylindrical battery cell provided for some embodiments of the present application;

[0158] Figure 13 unfolding view of a tab of a cylindrical battery cell provided for some embodiments of the present application;

[0159] Figure 14 enlarged view at G; Figure 4 enlarged view at H;

[0160] Figure 15 projection view of a pressure relief mechanism and a tab of a cylindrical battery cell provided for some embodiments of the present application;

[0161] Figure 16 enlarged view at I; Figure 15 enlarged view at J;

[0162] Figure 17 projection view of a pressure relief mechanism and a tab of a cylindrical battery cell provided for some embodiments of the present application;

[0163] Figure 18 enlarged view at K; Figure 17 enlarged view at L;

[0164] Figure 19 enlarged view at M; Figure 15 enlarged view at N;

[0165] Figure 20 enlarged view at O; Figure 15 enlarged view at P;

[0166] Figure 21 projection view of an electrode assembly and a current collecting member of a cylindrical battery cell provided for some embodiments of the present application;

[0167] Figure 22Projectional schematic views of an electrode assembly and a current collecting member of a cylindrical battery cell provided for some embodiments of the present application;

[0168] Figure 23 Projectional schematic views of an electrode assembly, a current collecting member and an electrode terminal of a cylindrical battery cell provided for some embodiments of the present application;

[0169] Figure 24 Projectional schematic views of a current collecting member and a pressure relief portion of a cylindrical battery cell provided for some embodiments of the present application;

[0170] Figure 25 Partial sectional views of a cylindrical battery cell provided for some embodiments of the present application.

[0171] In the drawings, each figure is:

[0172] 1000 - battery device; 2000 - controller; 3000 - motor; 100 - cylindrical battery cell; 10 - electrode assembly; 101 - center hole; 102 - first cut-off groove; 103 - first groove bottom surface; 104 - winding start end; 105 - winding end; 106 - second cut-off groove; 107 - second groove bottom surface; 108 - first notch groove; 109 - third groove bottom surface; 1010 - second notch groove; 1011 - fourth groove bottom surface; 1 - tab; 1a - positive tab; 1b - negative tab; 11 - tab main body; 11a - first tab main body; 11b - second tab main body; 111 - active material layer; 112 - main body winding part; 112a - first main body winding part; 112b - second main body winding part; 113 - main body coil part; 12 - tab ear; 12a - positive tab ear; 12b - negative tab ear; 121 - tab ear winding part; 121a - first tab ear winding part; 121b - second tab ear winding part; 1211 - cut piece; 12111 - bent section; 121111 - first bent part; 121112 - second bent part; 1212 - transition connection part; 12121 - winding start section; 12122 - winding middle section; 12123 - winding end section; 122 - tab ear coil part; 13 - insulation layer; 14 - tab winding part; 14a - first tab winding part; 14b - second tab winding part; 15 - tab coil part; 2 - separator; 20 - outer case; 201 - first groove; 202 - rolling groove; 21 - case; 211 - second end wall; 212 - side wall; 2121 - protrusion part; 22 - end cover; 221 - first end wall; 2211 - pressure relief mechanism; 22111 - pressure relief part; 22112 - weak part; 2212 - first wall; 30 - current collecting member; 30a - first current collecting member; 30b - second current collecting member; 301 - exhaust through hole; 31 - current collecting main body; 32 - guide part; 321 - first edge; 40 - first welding part; 50 - electrode terminal; 60 - second welding part; 200 - box; 210 - first part; 220 - second part; P - main body part; M1 - first projection end point; M2 - second projection end point; M3 - first circular arc line; M4 - second circular arc line; M5 - first span area; N1 - third projection end point; N2 - fourth projection end point; N3 - third circular arc line; N4 - fourth circular arc line; N5 - second span area; L - winding axis; Z - first direction; Y - radial direction; E - circumferential direction; W - winding direction; X - length direction. DETAILED DESCRIPTION

[0173] Embodiments of the present application are described in detail below with reference to examples illustrated in the attached drawings, in which like or similar elements or parts are denoted by like reference numerals throughout the drawings. The embodiments described below are examples and are intended to explain the present application, and are not to be understood as limiting the present application.

[0174] If there is no special description, all the embodiments and optional embodiments of the embodiments of the application can be combined to form new technical solutions.

[0175] If there is no special description, all the technical features and optional technical features of the embodiments of the application can be combined to form new technical solutions.

[0176] In the description of the embodiments of the application, it should be understood that the orientation or positional relationship indicated by the terms "length", "width", "inner", "outer" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application.

[0177] In addition, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features.

[0178] In the description of the embodiments of the application, the meaning of "multiple" is more than two, and "more than two" includes two, unless otherwise explicitly specified and limited. Accordingly, the meaning of "multiple groups" is more than two groups, including two groups.

[0179] In the description of the embodiments of the application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0180] In the description of the application, the term "and / or" is only a description of the association relationship between the associated objects, which means that there can be three kinds of relationships, for example, A and / or B, which can represent: A exists, A and B exist, and B exists. In addition, in the application, the character " / ", generally represents that the front and rear associated objects have an "or" relationship.

[0181] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the technical terms "adjacent", "adjacent to" refer to close in position. For example, A1, A2 and B three components, the distance between A1 and B is greater than the distance between A2 and B, then A2 is closer to B than A1, that is, A2 is adjacent to B, and it can also be said that B is adjacent to A2, in other words, A2 is adjacent to B. For another example, when there are multiple C components, the multiple C components are C1, C2, CN respectively, and when one of the C components, such as C2, is closer to the B component than the other C components, then B is adjacent to C2, and it can also be said that C2 is adjacent to B, in other words, C2 is adjacent to B.

[0182] Although the present application has been described with reference to the preferred embodiments, various modifications can be made to it without departing from the scope of the present application, and equivalent components can be substituted therefor. In particular, the technical features mentioned in each embodiment can be combined in any manner as long as there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0183] From the development of market situation, the application of battery device is more and more extensive. The battery device is not only applied to the energy storage system such as hydroelectric power station, thermal power station, wind power station and solar power station, but also widely applied to electric vehicles such as electric bicycle, electric motorcycle, electric automobile and the like, and many fields such as military equipment and aerospace. With the continuous expansion of the application field of battery device, the demand of market is also increasing. And the capacity of battery device is getting larger and larger, and the performance requirement of battery device is getting higher and higher.

[0184] In the related art, the battery device usually includes one or more battery monomers. When the battery monomer appears external short circuit, overcharge, needle puncture, flat plate impact and the like in the use process of the battery monomer, heat runaway is easily caused.

[0185] The battery monomer refers to the smallest unit for storing and outputting electric energy. Among them, the battery monomer can be in the shape of a cylinder, a flat body, a cuboid or other shapes, and the battery monomer with a shape approximately in the shape of a cylinder is a cylindrical battery monomer.

[0186] The cylindrical battery monomer mainly includes a cylindrical shell and an electrode assembly arranged in the shell, and a pressure relief mechanism can be arranged on the shell. In the process of heat runaway of the cylindrical battery monomer, when the pressure value in the cylindrical battery monomer reaches a threshold value, the pressure relief mechanism will open to form an exhaust passage, and the high-temperature and high-pressure medium such as high-temperature and high-pressure flue gas and high-temperature and high-pressure particulate matter in the cylindrical battery monomer will mainly spread towards the pressure relief mechanism of the shell and be discharged to the outside of the shell through the exhaust passage, realizing the effect of directional pressure relief.

[0187] The electrode assembly mainly comprises two polar pieces with opposite polarities, which are a positive polar piece and a negative polar piece. The positive polar piece and the negative polar piece are alternately stacked and wound to form a winding structure. The polar piece generally comprises a polar piece main body and a tab.

[0188] In some cases, the tab is a full tab, and the tab layers of the tab and between the tab layers have a relatively large mutual binding effect, that is, the tab itself has a relatively large binding effect. For example, after the polar piece is wound to form the electrode assembly, the tab can be subjected to a bending process to gather together the end region of the polar piece main body away from the tab, forming a relatively dense accumulation layer. On the one hand, the gap between the tab layers of the tab can be reduced, facilitating the welding of the tab and the current collecting member. On the other hand, the tab can achieve a relatively strong binding effect on the entire polar piece, to some extent, to ensure the structural integrity of the electrode assembly and facilitate the protection of the charge-discharge performance of the electrode assembly.

[0189] Based on the self-binding effect of the tab, the tab can have a relatively strong hindering effect on the high-temperature and high-pressure medium. In this way, the discharge of the high-temperature and high-pressure medium generated by the cylindrical battery cell during thermal runaway is limited, so that the discharge rate of the high-temperature and high-pressure medium is relatively low, and it is difficult to spread to the pressure relief mechanism and be discharged to the outside of the shell in time, but it will accumulate inside the cylindrical battery cell, resulting in a relatively low efficiency and poor effect of the cylindrical battery cell through the pressure relief mechanism for directional pressure relief. With the continuous thermal runaway of the cylindrical battery cell, the pressure value inside the cylindrical battery cell will continue to increase, so that the cylindrical battery cell has a relatively large explosion risk, thereby reducing the reliability of the cylindrical battery cell.

[0190] Based on the above considerations, the embodiments of the present application provide a cylindrical battery monomer, a battery device and an electric device. The electrode assembly includes a plurality of tab winding portions distributed along the winding direction of the electrode assembly. Along the winding direction of the electrode assembly, a first cutting groove is provided between any two adjacent tab winding portions. The first cutting groove penetrates the end surface of the tab away from the tab main body and is wound at least one turn along the winding direction. The plurality of tab winding portions are disconnected by the first cutting groove. Under the action of the first cutting groove wound at least one turn, the mutual binding action between the plurality of tab winding portions is weakened, and the mutual binding action between the plurality of tab winding portions of the tab formed with the tab winding portion, and the binding action between the tab winding portion and the tab ring portion are also weakened. At least one end of the shell along the first direction is provided with a pressure relief portion, and the pressure relief portion is configured to at least partially open to form an exhaust passage when pressure relief. In the process of thermal runaway of the cylindrical battery monomer, the binding action between the plurality of tab winding portions is easily broken under the action of air pressure, and the mutual binding action between the plurality of tab winding portions, and the binding action between the tab winding portion and the tab ring portion are also easily broken, so that the tab is easily loosened under the action of air pressure, and even discharged to the outside of the shell through the pressure relief portion. In this way, the hindering effect of the tab on the high-temperature and high-pressure medium can be reduced, and the high-temperature and high-pressure medium can spread towards the pressure relief portion, and be discharged to the outside of the shell through the exhaust passage formed by the opening of the pressure relief portion. In this way, the discharge rate and efficiency of the high-temperature and high-pressure medium can be improved, so that the cylindrical battery monomer can realize efficient directional pressure relief effect, thereby improving the reliability of the cylindrical battery monomer.

[0191] The cylindrical battery monomer related by the embodiments of the present application refers to the smallest unit for storing and outputting electric energy. The cylindrical battery monomer can be a secondary battery or a primary battery. The secondary battery refers to a cylindrical battery monomer that can be activated by charging after discharging. The cylindrical battery monomer can be a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel hydrogen battery, a nickel cadmium battery, a lead-acid battery, etc. The cylindrical battery monomer can be a cylinder, a flat body, a cuboid or other shapes, etc.

[0192] The battery device related by the embodiments of the present application can be a single physical module including one or more cylindrical battery monomers for providing voltage and capacity. When there are multiple cylindrical battery monomers, the multiple cylindrical battery monomers are connected in series, connected in parallel or mixedly connected through a busbar component. The mixedly connected refers to that the multiple cylindrical battery monomers are connected in series and in parallel.

[0193] 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, the multiple cylindrical battery cells can be fixed to form a battery module by a cable tie or the like. As an example, the multiple cylindrical battery cells can be fixed to form a battery module by an end plate, a side plate or the like.

[0194] In some embodiments, the battery device can be a battery pack, which can include a box body and cylindrical battery cells. As an example, the cylindrical battery cells can be directly accommodated in the box body. As an example, multiple cylindrical battery cells can first form one or more battery modules, and then be accommodated in the box body.

[0195] The cylindrical battery cell and the battery device involved in the embodiments of the present application can be used in an energy storage device using the cylindrical battery cell or the battery device as an energy storage element.

[0196] The energy storage device involved in the embodiments of the present application can be an energy storage container or an energy storage cabinet. The energy storage device can be used in an energy storage power station, a wind power system, a solar power system, a mobile power system or a temporary power supply system, etc. The energy storage device can store electrical energy as needed and output electrical energy at an appropriate time. For example, the energy storage device can store electrical energy during the off-peak period of electricity consumption, and provide electrical energy for related users or electrical devices during the peak period of electricity consumption. The energy storage device can include one or more battery clusters, and the battery cluster includes multiple battery devices. In the battery cluster, the multiple battery devices can be connected in series through a current collection component 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.

[0197] In some embodiments, the energy storage device can further include a cabinet body, and the battery cluster is accommodated in the cabinet body.

[0198] The cylindrical battery cell and the battery device provided by the embodiments of the present application can also be used in an electrical device using the cylindrical battery cell or the battery device as a power source.

[0199] The electrical device can be, but is not limited to, a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, an electric vehicle, a vehicle, a ship, a spacecraft, etc. The electric toy can include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy and an electric plane toy, etc. The spacecraft can include an airplane, a rocket, a space shuttle and a spacecraft, etc. According to the power source, the vehicle can be a fuel car, a gas car or a new energy car, and the new energy car can be a pure electric car, a hybrid electric car or a range extended car, etc. According to the driving mode, the vehicle can be a front-wheel drive car, a rear-wheel drive car or an all-wheel drive car.

[0200] For ease of description, embodiments of the present application are described by taking the electric device as a vehicle.

[0201] In some embodiments, referring to Figure 1 , Figure 1 A schematic diagram of a vehicle is provided for some embodiments of the present application. The vehicle is internally provided with a battery device 1000, which can be arranged at the bottom, head or tail of the vehicle. The battery device 1000 can be used for power supply of the vehicle, for example, the battery device 1000 can be used as the operating power supply of the vehicle. The vehicle can 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 demand of the vehicle during starting, navigation and driving.

[0202] In some embodiments, the battery device 1000 can not only be used as the operating power supply of the vehicle, but also be used as the driving power supply of the vehicle, instead of or partially instead of fuel or natural gas to provide driving power for the vehicle.

[0203] In some embodiments, referring to Figure 2 , Figure 2 An exploded view of the battery device 1000 is provided for some embodiments of the present application. The battery device 1000 can include a box 200 and a cylindrical battery cell 100. The box 200 is a structure with an internal space, and the internal space of the box 200 is used to accommodate the cylindrical battery cell 100.

[0204] The box 200 can adopt various structures. In some embodiments, the box 200 can include a first part 210 and a second part 220, the first part 210 and the second part 220 are covered with each other and jointly define the internal space of the box 200, and the internal space of the box 200 is a closed space. Here, closed means covered or closed, which can be sealed or unsealed. That is, the box 200 can be a sealed structure or an unsealed structure.

[0205] Among them, the first part 210 and the second part 220 can be hollow structures with an opening at one end, and the opening side of the first part 210 is covered on the opening side of the second part 220, so that the first part 210 and the second part 220 jointly 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 structure, and the second part 220 is covered on the opening side of the first part 210, so that the first part 210 and the second part 220 jointly define the internal space of the box 200.

[0206] Among them, the box 200 composed of the first part 210 and the second part 220 can be various shapes, such as a cylinder, a cuboid, etc.

[0207] In some embodiments, the plurality of cylindrical battery cells 100 can be connected in series, in parallel, or in a mixed connection to form a whole, and then the whole formed by the plurality of cylindrical battery cells 100 is directly accommodated in the internal space of the box 200. In other embodiments, the plurality of cylindrical battery cells 100 can be connected in series, in parallel, or in a mixed connection first, and then arranged and fixed to form a battery module, and the battery module is accommodated in the internal space of the box 200. In yet other embodiments, the plurality of cylindrical battery cells 100 can be connected in series, in parallel, or in a mixed connection first, and then arranged and fixed to form a plurality of battery modules, and the plurality of battery modules are connected in series, in parallel, or in a mixed connection to form a whole, and then accommodated in the internal space of the box 200.

[0208] In some embodiments, please refer to Figure 1 and Figure 2 , the box 200 of the battery device 1000 can be part of the chassis structure of the vehicle. For example, part of the box 200 can be at least part of the floor of the vehicle, or part of the box 200 can be at least part of the cross beam and the longitudinal beam of the vehicle.

[0209] In some embodiments, please refer to Figures 3 to 5 , and other drawings. Among them, Figure 3 is a perspective view of the cylindrical battery cell 100 provided in some embodiments of the present application, Figure 4 is Figure 3 a sectional view along A-A, Figure 5 is Figure 3 a schematic view of the electrode assembly 10 of the cylindrical battery cell 100 provided. The cylindrical battery cell 100 provided in the embodiments of the present application can include an electrode assembly 10 and a housing 20.

[0210] The electrode assembly 10 is a component in the cylindrical battery cell 100 where electrochemical reactions occur. Among them, the electrode assembly 10 is mainly formed by alternately stacking and winding the positive electrode sheet 1a and the negative electrode sheet 1b, and a diaphragm 2 is arranged between the positive electrode sheet 1a and the negative electrode sheet 1b. Among them, the diaphragm 2 is used to isolate the positive electrode sheet 1a and the negative electrode sheet 1b, so as to insulate the positive electrode sheet 1a and the negative electrode sheet 1b.

[0211] Among them, the number of electrode assemblies 10 in the cylindrical battery cell 100 can be one or more.

[0212] Among them, the electrode assembly 10 can also be referred to as a bare cell, a winding body, etc.

[0213] In some embodiments, the cylindrical battery cell 100 can further include an electrolyte, which functions to conduct ions between the positive electrode tab 1a and the negative electrode tab 1b. In some embodiments, the electrolyte can be in a liquid state, a gel state, or a solid state.

[0214] The housing 20 is configured to define an internal environment of the cylindrical battery cell 100, and the housing 20 is configured to accommodate the electrode assembly 10 and the electrolyte.

[0215] In some embodiments, please refer to Figures 3 to 5 , and in combination with other drawings. The housing 20 can include a shell 21 and an end cap 22, and the shell 21 and the end cap 22 are configured to jointly define an internal environment of the cylindrical battery cell 100, and the internal environment defined by the shell 21 and the end cap 22 is configured to accommodate the electrode assembly 10 and the electrolyte.

[0216] In some embodiments, the housing 20 can be in a cylindrical shape. Specifically, the shell 21 can be in a cylindrical shape.

[0217] In some embodiments, as shown in Figure 5 , the shell 21 and the end cap 22 can be separate components. Specifically, the shell 21 has an opening, and the end cap 22 is configured to cover the opening of the shell 21 to jointly define the internal environment of the cylindrical battery cell 100, and to isolate the internal environment of the cylindrical battery cell 100 from the external environment. Alternatively, the shell 21 and the end cap 22 can be in an integrated structure. Specifically, the end cap 22 and the shell 21 can form a common connection surface before the electrode assembly 10 is accommodated in the shell, and the end cap 22 is configured to cover the shell 21 after the electrode assembly 10 is accommodated in the shell, and when the electrode assembly 10 needs to be encapsulated.

[0218] In some embodiments, the housing 20 can be in a sealed structure, or in a non-sealed structure. As an example, the housing 20 is in a sealed structure, and the housing 20 is configured to protect the electrode assembly 10, and to prevent electrolyte leakage to some extent. As another example, the housing 20 is in a non-sealed structure, and the housing 20 is configured to protect the electrode assembly 10, and a sealing bag can be further included between the housing 20 and the electrode assembly 10, and the sealing bag is configured to encapsulate the electrode assembly 10 and the electrolyte. Specifically, the sealing bag can be in a bag-shaped insulating structure, a Mylar film, or the like.

[0219] In some embodiments, as shown in Figures 3 to 5 , the number of the end cap 22 can be one, and the end cap 22 is configured to be disposed at one end of the shell 21. Alternatively, the number of the end cap 22 can be two, and the two end caps 22 are configured to be disposed at opposite ends of the shell 21.

[0220] In some embodiments, the shell 21 and the end cap 22 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, or the like.

[0221] Please refer to Figures 3 to 11 , and in conjunction with other drawings. Among them, Figure 6 is Figure 3 a perspective view of the electrode assembly 10 of the cylindrical battery cell 100 provided by the present application before the tab 12 is bent. Figure 7 is Figure 4 an enlarged view of B in Figure 8 is Figure 4 an enlarged view of C in Figure 4 , Figure 7 and Figure 8 in them, the tab ring part 122 and the plurality of tab winding parts 121 are divided by dashed lines. Figure 9 is a projection schematic diagram of the pressure relief part 22111 and the tab 12 of the cylindrical battery cell 100 provided by some embodiments of the present application, specifically, the front projection of the pressure relief part 22111 and the front projection of the tab 12 on the projection plane perpendicular to the first direction Z. The front projection of the tab 12 on the projection plane perpendicular to the first direction Z includes the front projection of the root position of each tab winding part 121, and the front projection of the tab ring part 122. The root position of the tab winding part 121 can be the transition connection part 1212 of the tab winding part 121. Figure 9 in which the outer contour line of the pressure relief part 22111, the contour line of the first cutout groove 102, the contour line of the first notch groove 108 and the contour line of the second notch groove 1010 are all dashed lines. Figure 10 is an unfolded schematic diagram of the tab 1 of the cylindrical battery cell 100 provided by some embodiments of the present application, Figure 11 is Figure 10 an enlarged view of D in Figure 10 and Figure 11 in them, the tab ring part 122 and the plurality of tab winding parts 121 are divided by dashed lines. Figure 11In some embodiments, the transition connection portion 1212 and the section 1211 of the tab winding portion 121 are divided by a dashed line. The cylindrical battery cell 100 provided by the embodiments of the present application includes a shell 20 and an electrode assembly 10. The shell 20 is provided with a pressure relief portion 22111 at at least one end in the first direction Z, and the pressure relief portion 22111 is configured to be at least partially opened when pressure relief occurs. At least part of the electrode assembly 10 is arranged in the shell 20. The electrode assembly 10 is in a winding structure, and the electrode assembly 10 includes two electrode tabs 1 with opposite polarities. At least one electrode tab 1 includes an electrode tab main body 11 arranged in the first direction Z and an electrode tab 12, and the electrode tab main body 11 is coated with an active material layer 111, and at least part of the electrode tab 12 is not coated with the active material layer 111. In a projection plane perpendicular to the first direction Z, at least part of the orthogonal projection of the electrode tab 12 is located within the orthogonal projection of the pressure relief portion 22111. The electrode tab 12 includes a plurality of tab winding portions 121 distributed along the winding direction W of the electrode assembly 10, and a first cut-off groove 102 is arranged 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 surface of the electrode tab 12 away from the electrode tab main body 11. The first cut-off groove 102 winds at least one turn along the winding direction W of the electrode assembly 10.

[0222] The pressure relief portion 22111 refers to a part of the shell 20 that can be at least partially opened when pressure relief occurs. It can be understood that the shell 20 includes a pressure relief mechanism 2211, and the pressure relief mechanism 2211 includes the pressure relief portion 22111, i.e., the pressure relief portion 22111 is at least part of the pressure relief mechanism 2211.

[0223] The pressure relief mechanism 2211 is a mechanism that can release the internal pressure of the cylindrical battery cell 100 when the internal pressure of the cylindrical battery cell 100 reaches a threshold value. For example, when the cylindrical battery cell 100 is working normally, the gas pressure inside the cylindrical battery cell 100 is less than the opening pressure value of the pressure relief mechanism 2211, the pressure relief mechanism 2211 is in a closed state, and the gas inside the cylindrical battery cell 100 is not in communication with the gas outside. When the cylindrical battery cell 100 is in thermal runaway due to internal and external factors such as overcharge, overdischarge, overheating, mechanical impact, etc., a large amount of high-temperature and high-pressure medium is generated inside the cylindrical battery cell 100, so that the pressure inside the cylindrical battery cell 100 is greater than the opening pressure value of the pressure relief mechanism 2211, and the pressure relief mechanism 2211 changes from a closed state to an 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.

[0224] When the cylindrical battery cell 100 is in thermal runaway, at least part of the pressure relief portion 22111 is opened to achieve directional pressure relief.

[0225] For the convenience of description, it is defined that the at least one end of the shell 20 along the first direction Z is provided with a first end wall 221, and the first end wall 221 is provided with a pressure relief mechanism 2211. Specifically, as shown in Figure 4 and Figure 7 , the first end wall 221 includes a first wall 2212 and the above-mentioned pressure relief mechanism 2211, and the pressure relief mechanism 2211 is connected to the first wall 2212. Among them, the first end wall 221 is the end structure of the at least one end of the shell 20 along the first direction Z. The first wall 2212 is the solid wall of the at least one end of the shell 20 along the first direction Z, which is the part of the first end wall 221 except the pressure relief mechanism 2211, and the first wall 2212 and the electrode assembly 10 are oppositely arranged along the first direction Z. Among them, the pressure relief mechanism 2211 can be integrally formed on the first wall 2212, as shown in Figure 4 and Figure 7 ; or the pressure relief mechanism 2211 can also be separately arranged on the first wall 2212.

[0226] Among them, the shell 21 of the shell 20 can be provided with the pressure relief mechanism 2211, and it can be understood that the first end wall 221 is one part of the shell 21. The end cover 22 of the shell 20 can also be provided with the pressure relief mechanism 2211, and it can be understood that, as shown in Figure 4 and Figure 7 , the first end wall 221 is at least part of the end cover 22.

[0227] Among them, one end of the shell 20 along the first direction Z is provided with the first end wall 221, that is, one end of the shell 20 along the first direction Z is provided with the pressure relief mechanism 2211, as shown in Figure 4 and Figure 7 . Alternatively, both ends of the shell 20 along the first direction Z are provided with the first end wall 221, that is, both ends of the shell 20 along the first direction Z are provided with the pressure relief mechanism 2211.

[0228] As shown in Figure 5As shown, the electrode assembly 10 includes two polar pieces 1 with opposite polarities, that is, the electrode assembly 10 includes two polar pieces 1 with opposite polarities, and the two polar pieces 1 can be a positive polar piece 1a and a negative polar piece 1b respectively. Among them, the positive polar piece 1a can include a polar piece body 11 and a tab 12 arranged along the first direction Z, and the polar piece body 11 of the positive polar piece 1a is the first polar piece body 11a, and the tab 12 of the positive polar piece 1a is the positive tab 12a. Among them, the negative polar piece 1b can also include a polar piece body 11 and a tab 12 arranged along the first direction Z, and the polar piece body 11 of the negative polar piece 1b is the second polar piece body 11b, and the tab 12 of the negative polar piece 1b is the negative tab 12b. It can be understood that the above-mentioned polar piece body 11 can be the polar piece body 11 of the positive polar piece 1a, which is the first polar piece body 11a; It can also be the polar piece body 11 of the negative polar piece 1b, which is the second polar piece body 11b. The above-mentioned tab 12 can be the tab 12 of the positive polar piece 1a, which is the positive tab 12a; It can also be the tab 12 of the negative polar piece 1b, which is the negative tab 12b.

[0229] When the positive polar piece 1a and the negative polar piece 1b both include a polar piece body 11 and a tab 12, the polar piece body 11 of the positive polar piece 1a, the polar piece body 11 of the negative polar piece 1b and the separator 2 can constitute the main body part P of the electrode assembly 10, that is, the main body part P is mainly composed of the first polar piece body 11a, the second polar piece body 11b and the separator 2. Among them, the separator 2 is mainly arranged between the polar piece body 11 of the positive polar piece 1a and the polar piece body 11 of the negative polar piece 1b. Among them, the positive tab 12a and the negative tab 12b can be located at one end of the main body part P along the first direction Z, that is, one end of the electrode assembly 10 along the first direction Z is formed with the tab 12; Or, as Figures 4 to 6 shown, the positive tab 12a and the negative tab 12b are arranged at two ends of the main body part P along the first direction Z, that is, the two ends of the electrode assembly 10 along the first direction Z are both formed with the tab 12.

[0230] Among them, the polar piece body 11 and the tab 12 can be integrally formed, as Figure 5 and Figure 6 shown. Alternatively, the polar piece body 11 and the tab 12 can also be connected in separate bodies.

[0231] Among them, the tab 12 can be but not limited to a full tab 12.

[0232] The electrode assembly 10 is a winding structure, that is, the polar piece 1 is wound to form a winding structure. Specifically, the polar piece body 11 and the tab 12 of the polar piece 1 are both wound to make the polar piece body 11 and the tab 12 both have a winding structure. As an example, as Figure 3 , Figure 5 and Figure 6As shown, the pole piece 1 is wound to form a winding structure, so that the electrode assembly 10 can be substantially cylindrical. Correspondingly, the shell 20 is substantially cylindrical, so that the cylindrical battery monomer 100 is overall cylindrical.

[0233] It needs to be supplemented here that the cylindrical battery monomer 100 has a winding axis L, which is arranged along the first direction Z. And the pole piece 1 is wound with the winding axis L as the central axis, to be wound to form a winding structure, so that the electrode assembly 10 mainly formed by winding the diaphragm 2 and the two pole pieces 1 is a winding structure. Specifically, the pole piece body 11 and the tab 12 are both arranged around the winding axis L.

[0234] Among them, the pole piece body 11 can be completely coated with an active material layer 111; or the pole piece body 11 can also be partially coated with an active material layer 111, and the other part is not coated with an active material layer 111. The tab 12 can be completely uncoated with an active material layer 111; or the tab 12 can also be partially coated with an active material layer 111, and the other part is not coated with an active material layer 111. Among them, the active material layer 111 refers to a structural layer composed of active material.

[0235] For the sake of description, the winding direction W of the electrode assembly 10 can be referred to as the winding direction W, and the radial direction Y of the electrode assembly 10 can be referred to as the radial direction Y, specifically the radius direction of the electrode assembly 10. Among them, the winding direction W of the electrode assembly 10 refers to the direction of the pole piece 1 winding to form the electrode assembly 10, that is, the winding direction W of the tab 12, the winding direction W of the pole piece body 11, and also can be understood as the direction of the pole piece 1 winding from the winding starting end 104 to the winding end 105 involved below. The first direction Z is substantially the axial direction of the cylindrical battery monomer 100, and can also be the width direction of the pole piece 1. Among them, the first direction Z and the winding direction W of the electrode assembly 10 are substantially perpendicular, and the first direction Z and the radial direction Y of the electrode assembly 10 are substantially perpendicular. The first direction Z and the length direction X of the pole piece 1 are substantially perpendicular, that is, the width direction of the pole piece 1 and the length direction X of the pole piece 1 are substantially perpendicular.

[0236] 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. Among them, the first cut-off groove 102 penetrates the end face of the tab 12 away from the pole piece 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 arranged at intervals along the winding direction W.

[0237] The first truncated slot 102 is wound at least one turn along the winding direction W of the electrode assembly 10, which means that the first bottom surface 103 of the first truncated slot 102 is wound at least one turn along the winding direction W. It can be understood that the first bottom surface 103 is wound at least one turn along the winding direction W around the winding axis L. The first bottom surface 103 refers to the bottom wall of the first truncated slot 102 along the first direction Z, specifically the wall surface of the side wall of the first truncated slot 102 along the first direction Z close to the pole piece main body 11. Each first truncated slot 102 is provided with a first bottom surface 103. The first truncated slot 102 can be wound one turn, two turns, three turns, four turns, etc. along the winding direction W, and the number of turns of the first truncated slot 102 can not be an integer.

[0238] In some possible designs, as shown in Figure 7 、 Figure 8 、 Figure 10 and Figure 11 , the tab 12 further includes a tab loop portion 122 referred to below. The tab loop portion 122 is connected between the two adjacent tab winding portions 121 along the winding direction W, and is arranged between the two adjacent tab winding portions 121 along the radial direction Y. The tab loop portion 122 and the two adjacent tab winding portions 121 form the first truncated slot 102. Based on this, the first bottom surface 103 is arranged at the side edge of the tab loop portion 122 away from the pole piece main body 11 along the first direction Z. The first truncated slot 102 is wound at least one turn along the winding direction W, which means that the tab loop portion 122 is wound at least one turn along the winding direction W, and also means that the pole piece loop portion 15 referred to below is wound at least one turn along the winding direction W. Alternatively, in other possible designs, the tab 12 does not include the tab loop portion 122 referred to below. The first bottom surface 103 is formed at the side edge of the pole piece main body 11 close to the tab winding portion 121 along the first direction Z, so that the first bottom surface 103 is the boundary between the tab 12 and the pole piece main body 11. The first truncated slot 102 is wound at least one turn along the winding direction W, which means that the pole piece loop portion 15 referred to below is wound at least one turn along the winding direction W.

[0239] It should be noted here that the tab 12 can include a plurality of tab layers. The tab layer refers to the loop structure formed by winding the tab 12 one turn, and each tab layer is arranged around the outer periphery of the winding axis L. The winding of the tab 12 one turn means that the tab 12 is wound about 360°. All tab layers are sequentially distributed along the radial direction Y of the electrode assembly 10, and are sequentially distributed and connected along the winding direction W of the electrode assembly 10, so that all tab layers form a winding structure, i.e., the tab 12 is wound to form a winding structure.

[0240] Correspondingly, the pole piece body 11 can include a plurality of pole piece layers. The pole piece layer refers to a circle-shaped structure formed by winding the pole piece body 11 one turn, and each pole piece layer is arranged around the outer periphery of the winding axis L. Among them, winding the pole piece body 11 one turn means that the pole piece body 11 is wound about 360°. All pole piece layers are sequentially distributed along the radial direction Y of the electrode assembly 10, and all pole piece layers are also sequentially distributed and connected along the winding direction W of the electrode assembly 10, so that all pole piece layers form a winding structure, that is, the pole piece body 11 is wound to form a winding structure. Among them, among all the tab layers and all the pole piece layers, each tab layer and each pole piece layer are correspondingly arranged and connected along the first direction Z, so that the pole piece 1 is wound to form a plurality of circle-shaped structures, thereby being wound to form a winding structure. Among them, the circle-shaped structure wound by the pole piece 1 includes a pole piece layer and a tab layer.

[0241] The plurality of tab winding portions 121 are a plurality of portions divided by the tab 12 along the winding direction W, and each tab winding portion 121 is a winding structure. Specifically, as shown in FIG. 1, Figure 9 the plurality of tab winding portions 121 of the tab 12 are sequentially distributed along the winding direction W, and each tab winding portion 121 and each first cut-off groove 102 are alternately arranged along the winding direction W. Each tab winding portion 121 is arranged around the outer periphery of the winding axis L, so that the plurality of tab winding portions 121 are also sequentially distributed along the radial direction Y. It can be understood that among all the tab layers of the tab 12, each tab winding portion 121 is composed of a part of the tab layers.

[0242] It should be noted that when the pole piece 1 is in an unfolded state, as shown in FIG. 1, Figure 10 the plurality of tab winding portions 121 of the tab 12 are sequentially distributed along the length direction X of the pole piece 1, and each tab winding portion 121 and each first cut-off groove 102 are alternately arranged along the length direction X of the pole piece 1. It can be understood that when the pole piece 1 is in an unfolded state, the length direction X of the pole piece 1 can be the winding direction W of the electrode assembly 10.

[0243] It should also be noted that the pole piece 1 can be divided into a pole piece circle portion 15 and a plurality of pole piece winding portions 14 along the winding direction W. The plurality of pole piece winding portions 14 are sequentially distributed along the winding direction W, and the plurality of pole piece winding portions 14 are also sequentially distributed along the radial direction Y, and each pole piece winding portion 14 and the pole piece circle portion 15 are arranged around the outer periphery of the winding axis L. The plurality of tab winding portions 121 and the plurality of pole piece winding portions 14 are correspondingly arranged one by one, and each tab winding portion 121 is formed at one end of each pole piece winding portion 14 along the first direction Z. The pole piece circle portion 15 is connected between the adjacent two pole piece winding portions 14 along the winding direction W, and the pole piece circle portion 15 is also arranged between the adjacent two pole piece winding portions 14 along the radial direction Y, and the pole piece circle portion 15 and the adjacent two tab winding portions 121 are arranged to form the first cut-off groove 102.

[0244] Specifically, each pole piece winding portion 14 includes a tab winding portion 121 and a main body winding portion 112, the main body winding portion 112 and the tab winding portion 121 are distributed along the first direction Z and connected to constitute the pole piece winding portion 14. The pole piece ring portion 15 includes a main body ring portion 113, the main body ring portion 113 is connected between two adjacent main body winding portions 112 along the winding direction W, and the main body ring portion 113 is also arranged between the two adjacent main body winding portions 112 along the radial direction Y. Understandably, the main body winding portion 112 and the main body ring portion 113 each include a plurality of pole piece layers, the pole piece layers of the main body winding portion 112 and the tab layers of the corresponding tab winding portion 121 are arranged and connected in correspondence along the first direction Z, and the pole piece layers of the main body winding portion 112 and the tab layers of the corresponding tab winding portion 121 constitute the pole piece winding portion 14. When the tab 12 includes the tab ring portion 122 referred to below, the pole piece ring portion 15 includes the tab ring portion 122, the main body ring portion 113 and the tab ring portion 122 are distributed along the first direction Z and connected, and the pole piece layers of the main body ring portion 113 and the tab layers of the corresponding tab ring portion 122 constitute the pole piece ring portion 15; when the tab 12 does not include the tab ring portion 122 referred to below, the pole piece ring portion 15 only includes the main body ring portion 113, and the pole piece layers of the main body ring portion 113 constitute the pole piece ring portion 15.

[0245] The number of tab winding portions 121 can be 2, 3, 4, 5, etc.

[0246] At least part of the projection of the tab 12 in the projection plane perpendicular to the first direction Z is located within the projection of the pressure relief portion 22111, which means that at least part of the projection of the tab 12 is located within the area surrounded by the outer contour of the projection of the pressure relief portion 22111, so that at least part of the projection of the pole piece 1 is located within the projection of the pressure relief portion 22111.

[0247] The projection of the tab 12 in the projection plane perpendicular to the first direction Z refers to the 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 close to the pole piece main body 11 along the first direction Z, for example, the root position of the tab 12 can include the transition connection portion 1212 referred to below, or can include the tab ring portion 122 referred to below.

[0248] The projection of the pole piece 1 in the projection plane perpendicular to the first direction Z refers to the projection of the pole piece main body 11 of the pole piece 1.

[0249] The cylindrical battery monomer 100 provided by the embodiment of the present application, through the tab 12 of the electrode assembly 10, includes a plurality of tab winding portions 121 distributed along the winding direction W of the electrode assembly 10, along the winding direction W of the electrode assembly 10, a first cutting groove 102 is arranged between any two adjacent tab winding portions 121, the first cutting groove 102 penetrates the end face of the tab 12 away from the tab main body 11, and at least one winding is formed along the winding direction W, so that the plurality of tab winding portions 121 are disconnected through the first cutting groove 102, under the action of the first cutting groove 102 which is at least wound once, the mutual binding action between the plurality of tab winding portions 121 is weakened, and the mutual binding action between the plurality of tab winding portions 121 of the tab 1, the binding action between the tab winding portion 14 and the tab circle portion 15 is also weakened. At least one end of the shell 20 along the first direction Z is provided with a pressure relief portion 22111, and the pressure relief portion 22111 is configured to at least partially open when pressure relief, so that in the process of thermal runaway of the cylindrical battery monomer 100, the binding action between the plurality of tab winding portions 121 is easily broken under the action of air pressure, and the binding action between the plurality of tab winding portions 14 and the binding action between the tab winding portion 14 and the tab circle portion 15 are easily broken, so that the tab 1 is easily loose under the action of air pressure at least part of the pressure relief portion 22111, and even discharged to the outside of the shell 20 through the pressure relief portion 22111. In this way, the resistance of the tab 12 to high-temperature and high-pressure medium can be reduced, and the high-temperature and high-pressure medium can spread towards the pressure relief portion 22111 and be discharged to the outside of the shell 20 through the pressure relief portion 22111. In this way, the discharge rate and efficiency of the high-temperature and high-pressure medium can be improved, so that the cylindrical battery monomer 100 can realize efficient directional pressure relief effect, thereby helping to improve the reliability of the cylindrical battery monomer 100.

[0250] It should be further pointed out here that by providing the first cutting groove 102 in the tab 12, the structural strength of the tab 12 can be reduced. In this way, the mutual binding action between the plurality of tab winding portions 121 is easily broken under the action of air pressure, so as to facilitate the discharge of at least part of the tab 1 to the outside of the shell 20 through the pressure relief portion 22111, and improve the directional pressure relief efficiency of the cylindrical battery monomer 100.

[0251] It should be further pointed out here that by providing the first cutting groove 102 in the tab 12, the first cutting groove 102 of the tab 12 can form a channel for exhaust, so as to facilitate the discharge of high-temperature and high-pressure medium, so as to improve the directional pressure relief efficiency of the cylindrical battery monomer 100.

[0252] In some embodiments, please refer to Figures 4 to 10, and in combination with other drawings. Among the plurality of tab winding portions 121, which are distributed along the winding direction W of the electrode assembly 10, the innermost tab winding portion 121 is a first tab winding portion 121a. In a projection plane perpendicular to the first direction Z, at least a part of the orthographic projection of the first tab winding portion 121a is located within the orthographic projection of the pressure relief portion 22111.

[0253] It can be understood that, among the plurality of tab winding portions 121, one of the tab winding portions 121 is the first tab winding portion 121a, and the other tab winding portions 121 are arranged around 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.

[0254] Correspondingly, the tab sheet 1 is formed with a first tab sheet winding portion 14a of the first tab winding portion 121a, and the other tab sheet winding portions 14 of the tab sheet 1 are arranged around the outer periphery of the first tab sheet winding portion 14a.

[0255] In the projection plane perpendicular to the first direction Z, at least a part of the orthographic projection of the first tab winding portion 121a being located within the orthographic projection of the pressure relief portion 22111 means that at least a part of the orthographic projection of the first tab winding portion 121a is located within the area enclosed by the outer contour of the orthographic projection of the pressure relief portion 22111, so that at least a part of the orthographic projection of the first tab sheet winding portion 14a is located within the orthographic projection of the pressure relief portion 22111.

[0256] In the projection plane perpendicular to the first direction Z, the orthographic projection of the first tab winding portion 121a refers to the orthographic projection of the root position of the first tab winding portion 121a. Among them, the root position of the first tab winding portion 121a refers to the end area of the first tab winding portion 121a close to the tab body 11 along the first direction Z, for example, the root position of the first tab winding portion 121a includes the transition connection portion 1212 referred to below.

[0257] In the projection plane perpendicular to the first direction Z, the orthographic projection of the first tab sheet winding portion 14a refers to the orthographic projection of the tab body 11 of the first tab sheet winding portion 14a, that is, the orthographic projection of the body winding portion 112 of the first tab sheet winding portion 14a. Among them, the body winding portion 112 of the first tab sheet winding portion 14a is the first body winding portion 112a.

[0258] In this way, when the cylindrical battery cell 100 is in a thermal runaway process, the restraint between the first tab winding part 121a and the other tab winding parts 121 is easily broken under the action of air pressure, so that at least part of the tab sheet 1 is easily loosened under the action of air pressure, and even discharged to the outside of the shell 20 through the pressure relief part 22111. In this way, the tab sheet 1 is loosened and even discharged, which helps the cylindrical battery cell 100 to achieve efficient directional pressure relief effect.

[0259] In some embodiments, please refer to Figures 4 to 10 , and in combination with other drawings. In the projection plane perpendicular to the first direction Z, the orthographic projection of the first tab winding part 121a is completely located within the orthographic projection of the pressure relief part 22111.

[0260] In the projection plane perpendicular to the first direction Z, the orthographic projection of the first tab winding part 121a is located within the orthographic projection of the pressure relief part 22111, which means that the area surrounded by the outer contour of the orthographic projection of the first tab winding part 121a is located within the area surrounded by the outer contour of the orthographic projection of the pressure relief part 22111, so that the orthographic projection of the first tab winding part 14a is located within the area surrounded by the outer contour of the orthographic projection of the pressure relief part 22111.

[0261] In this way, during the pressure relief process of the cylindrical battery cell 100, the first tab winding part 14a is easily loosened under the action of air pressure, and even discharged to the outside of the shell 20 through the exhaust passage formed by opening the pressure relief part 22111. In this way, it helps to improve the directional pressure relief effect of the cylindrical battery cell 100.

[0262] In some embodiments, please refer to Figures 4 to 10 , and in combination with other drawings. The tab sheet 1 includes a first tab winding part 14a, and the first tab winding part 121a is formed at one end of the first tab winding part 14a along the first direction Z. The pressure relief part 22111 is configured to at least partially open and form an exhaust passage during pressure relief, and at least part of the first tab winding part 14a is discharged to the outside of the shell 20 through the exhaust passage.

[0263] It can be understood that the tab winding part 14 of the tab sheet 1, which forms the first tab winding part 121a, is the first tab winding part 14a, the main body winding part 112 of the first tab winding part 14a is the first main body winding part 112a, and the first tab winding part 121a is arranged at one end of the first main body winding part 112a along the first direction Z.

[0264] The exhaust passage refers to a passage formed through the wall of the shell 20 along the first direction Z with the pressure relief mechanism 2211, and can allow at least part of the first tab winding portion 14a to be discharged to the outside of the shell 20. When the exhaust passage is formed by at least part of the pressure relief portion 22111 being opened, at least part of the first tab winding portion 14a can be arranged in the first direction Z opposite the exhaust passage, so that at least part of the first tab winding portion 14a is discharged to the outside of the shell 20 through the exhaust passage under the action of the gas pressure. The wall of the shell 20 in which the pressure relief mechanism 2211 is formed can be the first end wall 221, that is, the first end wall 221 includes the pressure relief mechanism 2211.

[0265] By adopting the above technical solution, when the cylindrical battery monomer 100 undergoes a thermal runaway process, the first tab winding portion 14a can be discharged to the outside of the shell 20 through the exhaust passage under the action of the gas pressure, so that the hindering effect of the tab 12 on the high-temperature and high-pressure medium can be reduced. In this process, on the one hand, the high-temperature and high-pressure medium generated inside the cylindrical battery monomer 100 can be discharged together with the first tab winding portion 14a to the outside of the shell 20, and on the other hand, the tab 1 is opposite to the area of the pressure relief portion 22111. A larger passage is formed, and the passage will gradually increase with the discharge of the first tab winding portion 14a, so that the high-temperature and high-pressure medium can be discharged. In this way, the discharge efficiency of the high-temperature and high-pressure medium can be improved, so that the cylindrical battery monomer 100 can realize efficient directional pressure relief effect, thereby helping to improve the reliability of the cylindrical battery monomer 100.

[0266] In some embodiments, please refer to Figures 4 to 10 , and in combination with other drawings. The number of tab winding portions 121 is at least two, and along the winding direction W, the two adjacent tab winding portions 121 can be a first tab winding portion 121a and a second tab winding portion 121b, respectively. The first tab winding portion 121a and the second tab winding portion 121b are arranged around the outer periphery of the winding axis L. The second tab winding portion 121b is arranged around the outer periphery of the first tab winding portion 121a. Specifically, in the radial direction Y, the second tab winding portion 121b is located on the outer side of the first tab winding portion 121a. In the winding direction W, the second tab winding portion 121b is located on the outer side of the first tab winding portion 121a. The first cut-off groove 102 is formed between the first tab winding portion 121a and the second tab winding portion 121b.

[0267] Correspondingly, the number of the pole piece winding portions 14 is at least two, and the two adjacent pole piece winding portions 14 can be a first pole piece winding portion 14a and a second pole piece winding portion 14b in the winding direction W. The second pole piece winding portion 14b surrounds the outer periphery of the first pole piece winding portion 14a. Specifically, in the radial direction Y, the second pole piece winding portion 14b is located outside the first pole piece winding portion 14a. In the winding direction W, the second pole piece winding portion 14b is located outside the first pole piece winding portion 14a. In the winding direction W, the first pole piece winding portion 14a and the second pole piece winding portion 14b are connected by a pole piece ring portion 15. In the radial direction Y, the pole piece ring portion 15 is arranged between the first pole piece winding portion 14a and the second pole piece winding portion 14b. The first pole piece winding portion 14a, the second pole piece winding portion 14b, and the pole piece ring portion 15 form the first cut-off groove 102. In the first direction Z, the first groove bottom surface 103 of the first cut-off groove 102 is formed on the end surface of the pole piece ring portion 15 away from the pole piece main body 11.

[0268] The part of the pole piece 1 where the first tab winding portion 121a is formed is the first pole piece winding portion 14a, and the part of the pole piece 1 where the second tab winding portion 121b is formed is the second pole piece winding portion 14b. It can be understood that the tab winding portion 121 of the first pole piece winding portion 14a is the first tab winding portion 121a, and the main body winding portion 112 of the first pole piece winding portion 14a is the first main body winding portion 112a. The tab winding portion 121 of the second pole piece winding portion 14b is the second tab winding portion 121b, and the main body winding portion 112 of the second pole piece winding portion 14b is the second main body winding portion 112b.

[0269] In some embodiments, please refer to Figure 7 and Figure 9 together with other drawings. The tab 12 includes a first cut-off groove 102. In the projection plane perpendicular to the first direction Z, at least part of the first groove bottom surface 103 of the first cut-off groove 102 is orthogonally projected within the orthogonally projected pressure relief portion 22111.

[0270] It can be understood that the number of the tab winding portions 121 is two, and the two tab winding portions 121 are a first tab winding portion 121a and a second tab winding portion 121b.

[0271] By adopting the above technical solution, in the projection plane perpendicular to the first direction Z, the orthogonally projected first tab winding portion 121a and at least part of the orthogonally projected first groove bottom surface 103 of the first cut-off groove 102 are both within the orthogonally projected pressure relief portion 22111. Based on this, in the projection plane perpendicular to the first direction Z, the orthogonally projected first pole piece winding portion 14a and at least part of the orthogonally projected pole piece ring portion 15 are both within the orthogonally projected pressure relief portion 22111.

[0272] In some embodiments, the tab 12 comprises a plurality of first truncated grooves 102. At least part of the first groove bottom surface 103 of the innermost first truncated groove 102 is projected within the projection of the pressure relief portion 22111 at a projection plane perpendicular to the first direction Z.

[0273] In some embodiments, the tab 12 comprises a plurality of first truncated grooves 102. At least part of the first groove bottom surface 103 of the innermost first truncated groove 102 is projected within the projection of the pressure relief portion 22111 at a projection plane perpendicular to the first direction Z.

[0274] In some embodiments, the tab 12 comprises a plurality of first truncated grooves 102. At least part of the first groove bottom surface 103 of the innermost first truncated groove 102 is projected within the projection of the pressure relief portion 22111 at a projection plane perpendicular to the first direction Z.

[0275] By adopting the above technical solutions, the first tab winding portion 14a is facilitated to loosen from other tab winding portions 14 during pressure relief, so that at least part of the first tab winding portion 14a and the tab ring portion 15 can loosen under the action of air pressure, or even be discharged to the outside of the shell 20 through the exhaust passage opened by the pressure relief portion 22111 during thermal runaway of the cylindrical battery cell 100.

[0276] In this way, the tab 1 is facilitated to loosen under the action of air pressure, or even be discharged through the exhaust passage opened by the pressure relief portion 22111, which helps the cylindrical battery cell 100 to achieve efficient directional pressure relief and improve the problem of low directional pressure relief efficiency of the cylindrical battery cell 100.

[0277] In some embodiments, please refer to Figures 4 to 10 , and in combination with other drawings. The at least one tab 1 has a winding starting end 104 and a winding ending end 105 at two ends thereof along the winding direction W of the electrode assembly 10.

[0278] The winding starting end 104 and the winding ending end 105 are respectively arranged at two ends of the tab 1 along the winding direction W. The winding starting end 104 is an end surface of one end of the tab 1 along the winding direction W, and the winding ending end 105 is an end surface of the other end of the tab 1 along the winding direction W. In the radial direction Y of the electrode assembly 10, the winding ending end 105 is arranged outside the winding starting end 104, and the winding starting end 104 is closer to the winding axis L than the winding ending end 105.

[0279] It needs to be further explained that, among the plurality of tab winding portions 121 in the radial direction Y of the electrode assembly 10, the innermost tab winding portion 121 is formed with the winding start end 104, and the outermost tab winding portion 121 is formed with the winding end 105. Correspondingly, among the plurality of tab winding portions 14 in the radial direction Y of the electrode assembly 10, the winding start end 104 is formed at the innermost tab winding portion 14, and the winding end 105 is formed at the outermost tab winding portion 14.

[0280] It also needs to be further explained that the positive electrode tab 1a and the negative electrode tab 1b can each have a winding start end 104 and a winding end 105.

[0281] As an example, as shown in Figure 9 , the number of tab winding portions 121 is two. The first tab winding portion 121a is formed with the winding start end 104, and the second tab winding portion 121b is formed with the winding end 105. Correspondingly, the winding start end 104 is formed at the first tab winding portion 14a, and the winding end 105 is formed at the second tab winding portion 14b.

[0282] In some embodiments, please refer to Figures 4 to 10 , and in combination with other drawings. The winding start end 104 is formed at the first tab winding portion 14a. In the projection plane perpendicular to the first direction Z, the orthographic projection of the winding start end 104 is located within the orthographic projection of the pressure relief portion 22111.

[0283] In this way, when the pressure value inside the shell 20 reaches the threshold value, at least part of the first tab winding portion 14a close to the winding start end 104 can be discharged to the outside of the shell 20 through the exhaust passage, so that the first tab winding portion 14a is loosened and discharged through the exhaust passage under the action of air pressure, which helps to improve the directional pressure relief efficiency of the cylindrical battery monomer 100.

[0284] In some embodiments, please refer to Figures 4 to 6 , Figure 9 , and in combination with other drawings. The tab 12 is provided with a center hole 101 extending along the first direction Z, and each tab winding portion 121 is arranged around the outer periphery of the center hole 101. In the projection plane perpendicular to the first direction Z, the orthographic projection of the center hole 101 is located within the orthographic projection of the pressure relief portion 22111.

[0285] The electrode assembly 10 is provided with a center hole 101 extending along the first direction Z, which means that the center hole 101 penetrates both ends of the electrode assembly 10 along the first direction Z. Among them, in the radial direction Y of the electrode assembly 10, the winding start end 104 is closer to the center hole 101 than the winding end 105.

[0286] Each of the tab winding portions 121 is arranged around the outer periphery of the center hole 101, which means that the first tab winding portion 121a and the other tab winding portions 121 are arranged around the outer periphery of the center hole 101, and the first tab winding portion 14a and the other tab winding portions 14 are arranged around the outer periphery of the center hole 101. As an example, the first tab winding portion 121a and the second tab winding portion 121b are arranged around the outer periphery of the center hole 101, and correspondingly, the first tab winding portion 14a and the second tab winding portion 14b are arranged around the outer periphery of the center hole 101.

[0287] The first slot bottom surface 103 of the first cut-off slot 102 and the tab ring portion 15 are arranged around the outer periphery of the center hole 101.

[0288] The first tab winding portion 121a is closer to the center hole 101 than the other tab winding portions 121. As an example, the first tab winding portion 121a is closer to the center hole 101 than the second tab winding portion 121b, and correspondingly, the first tab winding portion 14a is closer to the center hole 101 than the second tab winding portion 14b.

[0289] The normal projection of the center hole 101 on the projection plane perpendicular to the first direction Z is located within the normal projection of the pressure relief portion 22111, so that the first tab winding portion 14a is arranged opposite to at least part of the pressure relief portion 22111 along the first direction Z, and at least part of the center hole 101 can be arranged opposite to and communicated with the exhaust passage formed by the opening of the pressure relief portion 22111 along the first direction Z. In this way, during the thermal runaway of the cylindrical battery cell 100, at least part of the first tab winding portion 14a opposite to the center hole 101 can move towards the center hole 101 under the action of air pressure, and the space of the center hole 101 is loose, that is, at least part of the tab 1 opposite to the center hole 101 can be loose under the action of air pressure. Moreover, at least part of the tab 1 opposite to the center hole 101 can be gradually released to the outside of the shell 20 through the exhaust passage formed by the opening of the pressure relief portion 22111. In this way, the arrangement of the center hole 101 facilitates the loose of the tab 1 under the action of air pressure, and facilitates the release of the tab 1 to the outside of the shell 20, thereby facilitating the exhaust and achieving the efficient directional pressure relief effect.

[0290] It should be noted that during the process that at least part of the tab 1 opposite to the center hole 101 is released to the outside of the shell 20 through the exhaust passage, at least part of the tab 1 close to the winding starting end 104 will be released to the outside of the shell 20 through the exhaust passage. In this way, at least part of the tab 1 opposite to the center hole 101 is loose and released through the exhaust passage, thereby facilitating the improvement of the directional pressure relief efficiency of the cylindrical battery cell 100.

[0291] In the process of the exhaust passage formed by the opening of the pressure relief portion 22111 of the pole piece 1, the space at the center hole 101 gradually increases with the exhaust of the pole piece 1, and it can be understood that the hole diameter of the center hole 101 gradually increases with the exhaust of the pole piece 1. In this way, it is convenient for the high-temperature and high-pressure medium to be discharged through the center hole 101, and the problem of low exhaust rate caused by the small hole diameter of the center hole 101 can be improved, so as to realize the efficient directional pressure relief effect.

[0292] In some embodiments, please refer to Figure 4 , and in combination with other drawings. The outer diameter of the electrode assembly 10 is D1, the diameter of the center hole 101 is D2, and D2 / D1 ∈ [5%, 25%].

[0293] 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.

[0294] In this way, the center hole 101 has a larger hole diameter, so that in the process of thermal runaway of the cylindrical battery monomer 100, the high-temperature and high-pressure medium inside the cylindrical battery monomer 100 is conveniently discharged through the center hole 101 to the pressure relief portion 22111, so as to realize the efficient directional pressure relief effect.

[0295] In some embodiments, please refer to Figure 9 , and in combination with other drawings. The number of turns of the first truncated groove 102 wound along the winding direction W of the electrode assembly 10 ∈ [2, 4].

[0296] Wherein, along the winding direction W, the number of turns of the first truncated groove 102 wound can be 2 turns, 3 turns, 4 turns, or greater than 2 turns and less than 3 turns, greater than 3 turns and less than 4 turns, etc.

[0297] In this way, it is helpful to weaken the mutual binding effect between the plurality of tab winding portions 121, thereby helping to weaken the mutual binding effect between the plurality of pole piece winding portions 14, so that in the process of thermal runaway of the cylindrical battery monomer 100, the binding effect between the plurality of tab winding portions 121 is broken under the action of air pressure, thereby facilitating the mutual binding effect between the plurality of pole piece winding portions 14 to be broken under the action of air pressure, so that at least part of the pole piece 1 opposite the pressure relief portion 22111 is loosened under the action of air pressure, and even discharged to outside the shell 20 through the pressure relief portion 22111. In this way, the discharge rate and efficiency of the high-temperature and high-pressure medium can be improved, so that the cylindrical battery monomer 100 can realize the efficient directional pressure relief effect, thereby helping to improve the reliability of the cylindrical battery monomer 100.

[0298] In some embodiments, please refer to Figures 4 to 9 The two pole pieces 1 each include a pole piece body 11 and a tab 12, and the tabs 12 of the two pole pieces 1 are respectively provided at both ends of the electrode assembly 10 in the first direction Z. The tab 12 of each pole piece 1 includes a plurality of the above-mentioned tab winding portions 121.

[0299] As can be understood, the tabs 12 of the two pole pieces 1 are each provided with the above-mentioned first cut-off groove 102.

[0300] As can be understood, the two pole pieces 1 are respectively a positive pole piece 1a and a negative pole piece 1b, and the positive pole piece 1a and the negative pole piece 1b each include a pole piece body 11 and a tab 12. The pole piece body 11 of the positive pole piece 1a is a first pole piece body 11a, and the tab 12 of the positive pole piece 1a is a positive tab 12a. The pole piece body 11 of the negative pole piece 1b is a second pole piece body 11b, and the tab 12 of the negative pole piece 1b is a negative tab 12b. The first pole piece body 11a, the second pole piece body 11b, and the separator 2 constitute a main portion P of the electrode assembly 10, and the positive tab 12a and the negative tab 12b are respectively provided at both ends of the main portion P in the first direction Z. In a projection plane perpendicular to the first direction Z, at least a part of the positive tab 12a and at least a part of the negative tab 12b each project within the projection of the pressure relief portion 22111.

[0301] The positive tab 12a includes a plurality of tab winding portions 121 distributed in the winding direction W, and in the positive tab 12a, between any two adjacent tab winding portions 121 in the winding direction W, the first cut-off groove 102 is provided. The negative tab 12b includes a plurality of tab winding portions 121 distributed in the winding direction W, and in the negative tab 12b, between any two adjacent tab winding portions 121 in the winding direction W, the first cut-off groove 102 is provided. That is, the first cut-off groove 102 is provided on both the positive tab 12a and the negative tab 12b.

[0302] 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.

[0303] As an example, such as Figure 9 As shown, 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.

[0304] In some embodiments, please refer to the following: Figure 12 and Figure 13 And in conjunction with other accompanying figures. Figure 12 This is a partially unfolded schematic diagram of the positive electrode 1a of a cylindrical battery cell 100 provided in some embodiments of this application. Figure 12 In the diagram, both the insulating layer 13 and the active material layer 111 are shown in cross-sectional lines. Figure 13 This is a partially unfolded schematic diagram of the negative electrode 1b of a cylindrical battery cell 100 provided in some embodiments of this application. Figure 13 In the diagram, the active material layer 111 is shown in cross-section. Figure 12 and Figure 13In some possible designs, as shown in

[0305] In the positive electrode tab 1a, the current collector can not be limited to an aluminum foil. In the negative electrode tab 1b, the current collector can be but is not limited to a copper foil.

[0306] In some embodiments, reference is made to Figure 12 and Figure 13 together with other drawings. The two electrode tabs 1 include a positive electrode tab 1a and a negative electrode tab 1b.

[0307] In some possible designs, as shown in Figure 12 together with other drawings. The positive electrode tab 1a is not coated with the active material layer 111.

[0308] It can be understood that the positive electrode tab 1a includes a first electrode tab body 11a and a positive electrode tab 12a. In this case, the current collector is electrically connected to the positive electrode tab 12a.

[0309] In this case, the first electrode tab body 11a can be completely coated with the active material layer 111, that is, the current collector is completely coated with the active material layer 111; and the positive electrode tab 12a is completely not coated with the active material layer 111. Based on this, in the first direction Z, the side edge of the active material layer 111 close to the positive electrode tab 12a is the boundary between the first electrode tab body 11a and the positive electrode tab 12a, that is, in the positive electrode tab 1a, the part coated with the active material layer 111 is the first electrode tab body 11a, and the part not coated with the active material layer 111 is the positive electrode tab 12a. Alternatively, the positive electrode tab 12a is completely not coated with the active material layer 111, and in the first direction Z, the end region of the first electrode tab body 11a close to the positive electrode tab 12a is not coated with the active material layer 111, and the rest of the first electrode tab body 11a 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.

[0310] In some possible designs, as shown in Figure 13 together with other drawings. The positive electrode tab 1a is not coated with the active material layer 111.

[0311] It can be understood that the positive electrode tab 1a includes a first electrode tab body 11a and a positive electrode tab 12a. In this case, the current collector is electrically connected to the positive electrode tab 12a.

[0312] The second tab body 11b can be completely coated with the active material layer 111, i.e., 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 side edge of the active material layer 111 close to the negative electrode tab 12b is the boundary between the second tab body 11b and the negative electrode tab 12b, i.e., in the negative electrode tab 1b, the part coated with the active material layer 111 is the second tab body 11b, and the part uncoated with the active material layer 111 is the negative electrode tab 12b. Alternatively, the negative electrode tab 12b is completely uncoated with the active material layer 111, and in the first direction Z, the end region of the second tab body 11b close to the negative electrode tab 12b is uncoated with the active material layer 111, and the rest of the second tab body 11b is coated with the active material layer 111; i.e., 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.

[0313] By not coating the tab 12 in at least one of the positive electrode tab 1a and the negative electrode tab 1b with the active material layer 111, only the tab 12 is cut during the process of cutting the tab 12 to form the tab winding part 121 and the first cutting groove 102, so that the part of the electrode tab 1 provided with the active material layer 111 is not cut, so that the first cutting groove 102 is formed in the part of the electrode tab 1 which is not provided with the active material layer 111, which can to some extent guarantee the performance of the active material layer 111, to some extent guarantee the performance of the electrode assembly 10, and thus the charge-discharge performance of the cylindrical battery cell 100.

[0314] In some embodiments, please refer to Figure 4 and Figure 14 , and in combination with other drawings. Among them, Figure 14 is Figure 4 an enlarged view of E in FIG. Figure 14 In FIG., the tab 12 and the tab body 11 are divided by a dashed line. The electrode assembly 10 has a winding axis L parallel to the first direction Z, and at least one tab winding part 121 is provided with a bending section 12111 in the first direction Z.

[0315] The bending section 12111 is the part of the tab winding part 121 bent relative to the tab body 11. Among them, the end of the tab winding part 121 away from the tab body 11 in the first direction Z is formed with the bending section 12111.

[0316] In some possible designs, as shown in Figure 14 and in combination with other drawings. The bending section 12111 includes a first bending part 121111, and the first bending part 121111 is bent in a direction close to the winding axis L relative to the tab body 11.

[0317] The first bending portion 121111 refers to the portion of the bending segment 12111 that is bent towards the direction close to the winding axis L relative to the pole piece body 11.

[0318] In some possible designs, as shown in Figure 14 , and in combination with other drawings. The bending segment 12111 includes a second bending portion 121112 that is bent towards the direction away from the winding axis L relative to the pole piece body 11.

[0319] The second bending portion 121112 refers to the portion of the bending segment 12111 that is bent towards the direction away from the winding axis L relative to the pole piece body 11.

[0320] In this way, the end region of the tab winding portion 121 away from the pole piece body 11 in the first direction Z can be bent to be gathered together to form a relatively dense stacking layer. In this way, on the one hand, the tab layer of the tab winding portion 121 and the gap between the tab layers can be reduced, facilitating the welding of the tab winding portion 121 and the current collecting member 30 described below. On the other hand, the pole piece 1 has a relatively strong binding effect under the bending of the tab 12, thereby improving the structural integrity and performance of the electrode assembly 10.

[0321] It should be noted here that the first bending portion 121111 is bent towards the direction close to the winding axis L, which means that the first bending portion 121111 is bent towards the direction close to the center hole 101. The second bending portion 121112 is bent towards the direction away from the winding axis L, which means that the second bending portion 121112 is bent towards the direction away from the center hole 101.

[0322] In some embodiments, please refer to Figure 4 and Figure 14 , and in combination with other drawings. Each tab winding portion 121 is provided with a bending segment 12111 in the first direction Z.

[0323] In this way, the end region of the tab 12 away from the pole piece body 11 in the first direction Z can be bent to be gathered together to form a relatively dense stacking layer.

[0324] In some embodiments, please refer to Figures 15 to 18 , and in combination with other drawings. In this embodiment, Figure 15 is a developed view of the pole piece 1 of the cylindrical battery cell 100 provided in another embodiment of the present application. Figure 15 In this embodiment, the tab ring portion 122 and the plurality of tab winding portions 121 are divided by dashed lines. Figure 16 is Figure 15 is an enlarged view of F in Figure 16In the middle, the transition connection 1212 of the electrode winding portion 121 and the segment 1211 are divided by dashed lines. Figure 17 The following is a projection schematic diagram of the pressure relief portion 22111 and the tab 12 of the cylindrical battery cell 100 provided in 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. Figure 17 In the figure, the outer contour lines of the pressure relief section 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 for Figure 17 Enlarged view at point G in the middle. Figure 18 In the diagram, the outer contour line of the pressure relief section 22111, the contour line of the first cut-off groove 102, and the contour line of the second cut-off groove 106 are all dashed lines. At least one electrode lug winding section 121 includes a plurality of segments 1211 distributed along the winding direction W of the electrode assembly 10, and in the electrode lug winding section 121, along the winding direction W of the electrode assembly 10, a second cut-off groove 106 is provided between any two adjacent segments 1211.

[0325] 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.

[0326] 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 lug winding portion 121 are sequentially distributed along the winding direction W of the electrode assembly 10, and each segment 1211 and each second cutting groove 106 are alternately arranged along the winding direction W of the electrode assembly 10. When the electrode 1 is in an unfolded state, as... Figure 10 As shown, the multiple segments 1211 of the electrode winding portion 121 are distributed sequentially along the length direction X of the electrode 1, that is, they are distributed sequentially along the length direction X of the electrode 12, and each segment 1211 and each second cutting groove 106 are alternately distributed along the length direction X of the electrode 1.

[0327] In some embodiments, please refer to the following: Figures 15 to 18 In conjunction with other accompanying drawings, 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.

[0328] The second slot bottom surface 107 refers to a slot bottom wall of the second truncated slot 106 along the first direction Z, specifically, a wall surface of a side slot wall of the second truncated slot 106 along the first direction Z close to the tab main body 11. Each of the second truncated slots 106 is provided with the second slot bottom surface 107.

[0329] In some possible designs, as shown in FIG. 1, the second slot bottom surface 107 is formed on a side edge of the transition connection portion 1212 along the first direction Z away from the tab main body 11. Figures 16 to 18 As shown in FIG. 1, the lug winding portion 121 further includes a transition connection portion 1212 referred to below, which is arranged between the segment 1211 and the tab main body 11 along the first direction Z, and the second slot bottom surface 107 of the second truncated slot 106 is formed on a side edge of the transition connection portion 1212 along the first direction Z away from the tab main body 11. Alternatively, in another possible design, the lug winding portion 121 does not include the transition connection portion 1212 referred to below, the segment 1211 contacts the tab main body 11 along the first direction Z, and the second slot bottom surface 107 of the second truncated slot 106 is formed on a side edge of the tab main body 11 along the first direction Z close to the segment 1211, so that the side edge of the segment 1211 along the first direction Z close to the tab main body 11 is a boundary between the tab main body 11 and the lug winding portion 121.

[0330] The second slot bottom surface 107 of the at least one second truncated slot 106 is located within the normal projection of the pressure relief portion 22111 on a projection plane perpendicular to the first direction Z, that is, the area surrounded by the outer contour of the normal projection of the second slot bottom surface 107 of the at least one second truncated slot 106 is located within the area surrounded by the outer contour of the normal projection of the pressure relief portion 22111. When the number of the second truncated slots 106 is one, the normal projection of the second slot bottom surface 107 is located within the normal projection of the pressure relief portion 22111 on the projection plane perpendicular to the first direction Z. When the number of the second truncated slots 106 is more than one, the normal projection of the second slot bottom surface 107 of all the second truncated slots 106 is located within the normal projection of the pressure relief portion 22111 on the projection plane perpendicular to the first direction Z, or the normal projection of part of the second slot bottom surface 107 of part of the second truncated slots 106 is located within the normal projection of the pressure relief portion 22111, and the normal projection of at least part of the second slot bottom surface 107 of part of the second truncated slots 106 is located outside the normal projection of the pressure relief portion 22111. Based on this, at least part of the normal projection of the lug 12 in which the second truncated slot 106 is formed is located within the normal projection of the pressure relief portion 22111, and at least part of the normal projection of at least one lug winding portion 121 in which the second truncated slot 106 is formed is located within the normal projection of the pressure relief portion 22111 on the projection plane perpendicular to the first direction Z.

[0331] 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, and in the at least one 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, so that the compactness of the stacking layer formed by the portion of the at least one tab winding portion 121 with the second cutting groove 106 is reduced. By locating the orthographic projection of the second groove bottom surface 107 of the at least one second cutting groove 106 in the orthographic projection of the pressure relief portion 22111 in the projection plane perpendicular to the first direction Z, the self-binding effect of the portion of the at least one tab winding portion 121 directly against the pressure relief portion 22111 is weakened under the action of the second cutting groove 106, so that the self-binding effect of the at least one tab winding portion 14 is also weakened. During the thermal runaway of the cylindrical battery cell 100, the binding effect of the at least one tab winding portion 121 directly against at least part of the pressure relief portion 22111 is easily broken under the action of the gas pressure, so that the at least one tab winding portion 14 is easily discharged to the outside of the shell 20 through the exhaust passage under the action of the gas pressure. In this way, it is helpful to realize the efficient directional pressure relief effect of the cylindrical battery cell 100 and improve the problem of low directional pressure relief efficiency of the cylindrical battery cell 100, thereby improving the reliability of the cylindrical battery cell 100.

[0332] It should be further pointed out here that the second cutting groove 106 is formed in the at least one tab winding portion 121, which can reduce the connection strength between the tab layers and the tab layers of the at least one tab winding portion 121. In this way, it is convenient for the binding effect of the at least one tab winding portion 121 directly against at least part of the pressure relief portion 22111 to be broken under the action of the gas pressure, so as to facilitate the at least one tab winding portion 14 to be discharged to the outside of the shell 20 through the pressure relief portion 22111, thereby improving the directional pressure relief efficiency of the cylindrical battery cell 100.

[0333] It should be further pointed out here that the at least one tab winding portion 121 of the positive electrode tab 12a can 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 second groove bottom surface 107 of the at least one second cutting groove 106 is located in the orthographic projection of the pressure relief portion 22111.

[0334] The at least one tab winding portion 121 of the negative electrode tab 12b can 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 second groove bottom surface 107 of the at least one second cutting groove 106 is located in the orthographic projection of the pressure relief portion 22111.

[0335] As an example, as shown in Figures 16 to 18 The first tab winding portion 121a includes a plurality of the above-mentioned segments 1211, and is provided with the above-mentioned second cutting groove 106. In this way, when the pressure value inside the shell 20 reaches the threshold value, the mutual binding action between the first tab winding portion 121a and other tab winding portions 121, and the self-binding action of the first tab winding portion 121a are broken under the action of the gas pressure, so that the first tab winding portion 14a is discharged to the outside of the shell 20 through the pressure relief portion 22111 under the action of the gas pressure, thereby achieving an efficient directional pressure relief effect.

[0336] In some embodiments, please refer to Figures 15 to 18 , and combine with other drawings. The plurality of tab winding portions 121 includes adjacent first tab winding portion 121a and second tab winding portion 121b, and the second tab winding portion 121b is arranged outside the first tab winding portion 121a.

[0337] It can be understood that, in the plurality of tab winding portions 121, the adjacent two tab winding portions 121 are the first tab winding portion 121a and the second tab winding portion 121b respectively. Among them, the second tab winding portion 121b surrounds the outer periphery of the first tab winding portion 121a. Specifically, the second tab winding portion 121b is located outside the first tab winding portion 121a along the radial direction Y, and is located outside the first tab winding portion 121a along the winding direction W.

[0338] In some embodiments, please refer to Figures 15 to 18 , and combine with other drawings. The first tab winding portion 121a includes a plurality of the above-mentioned segments 1211. In the first tab winding portion 121a, the orthographic projection of the second groove bottom surface 107 of at least one second cutting groove 106 is located within the orthographic projection of the pressure relief portion 22111 in the projection plane perpendicular to the first direction Z.

[0339] It can be understood that the first tab winding portion 121a includes a plurality of the above-mentioned segments 1211 distributed in sequence along the winding direction W, and in the first tab winding portion 121a, any two adjacent segments 1211 are provided with a second cutting groove 106 along the winding direction W.

[0340] By adopting the above technical solution, the self-binding action of the first tab winding portion 121a is weakened under the arrangement of the second cutting groove 106, so that when the pressure value inside the shell 20 reaches the threshold value, the first tab winding portion 14a is discharged to the outside of the shell 20 through the pressure relief portion 22111, so that the cylindrical battery monomer 100 realizes an efficient directional pressure relief effect.

[0341] It needs to be explained that, in the projection plane perpendicular to the first direction Z, when the orthographic projection of the first tab winding part 121a and the first groove bottom surface 103 of the first tab winding part 121a adjacent to the first tab winding part 121a is located within the outer contour of the orthographic projection of the pressure relief part 22111, the orthographic projection of the second groove bottom surface 107 of all the second tab winding part 121a of the second tab winding part 121a is completely located within the outer contour of the orthographic projection of the pressure relief part 22111.

[0342] In some embodiments, please refer to Figures 15 to 18 , and in combination with other drawings. The second tab winding part 121b includes a plurality of the above-mentioned segments 1211.

[0343] It can be understood that the second tab winding part 121b includes a plurality of the above-mentioned segments 1211 distributed in sequence along the winding direction W, and in the second tab winding part 121b, a second tab winding part 121b is formed between any two adjacent segments 1211 along the winding direction W.

[0344] Among them, the segment 1211 adjacent to the second tab winding part 121b of the first tab winding part 121a, the segment 1211 adjacent to the first tab winding part 121a of the second tab winding part 121b is provided with a first tab winding part 121a.

[0345] Among them, in the projection plane perpendicular to the first direction Z, the orthographic projection of the second groove bottom surface 107 of at least one second tab winding part 121b of the second tab winding part 121b can be located within the orthographic projection of the pressure relief part 22111, or not.

[0346] In some embodiments, please refer to Figures 15 to 17 , and in combination with other drawings. Among the plurality of segments 1211 of the second tab winding part 121b, the segment 1211 closest to the first tab winding part 121a is wound at least three times.

[0347] It can be understood that the segment 1211 between the second tab winding part 121b closest to the first tab winding part 121a and the first tab winding part 121a is wound at least three times along the winding direction W.

[0348] Among them, the segment 1211 closest to the first tab winding part 121a of the plurality of segments 1211 of the second tab winding part 121b can be wound 3, 4, 5, 6, 7, 8, 9, etc.

[0349] Among them, the number of turns of the segment 1211 refers to the number of layers of the tab layer corresponding to the segment 1211.

[0350] In this way, the section 1211 closest to the first cutting groove 102 in the second tab winding part 121b can better wrap the first cutting groove 102, and the problem of tab 12 collapse caused by the first cutting groove 102 can be improved, so that the overall restraint of the tab 12 can be improved, and the electrode assembly 10 has higher performance.

[0351] In some embodiments, please refer to Figure 17 , and in combination with other drawings. The number of turns of the section 1211 closest to the first tab winding part 121a in the plurality of sections 1211 of the second tab winding part 121b is ≤8.

[0352] The number of turns of the section 1211 closest to the first tab winding part 121a in the plurality of sections 1211 of the second tab winding part 121b can be 3 turns, 4 turns, 5 turns, 6 turns, 7 turns, 8 turns, or greater than 3 turns and less than 4 turns, greater than 4 turns and less than 5 turns, greater than 5 turns and less than 6 turns, greater than 6 turns and less than 7 turns, greater than 7 turns and less than 8 turns.

[0353] In this way, on the one hand, the section 1211 closest to the first cutting groove 102 in the second tab winding part 121b can better wrap the first cutting groove 102, and the problem of tab 12 collapse caused by the first cutting groove 102 can be improved, and on the other hand, the second cutting groove 106 can also be formed in the second tab winding part 121b to help improve the directional pressure relief efficiency of the cylindrical battery monomer 100.

[0354] In some embodiments, please refer to Figure 14 , and in combination with other drawings. The electrode assembly 10 has a winding axis L parallel to the first direction Z, and at least one section 1211 is provided with a bending segment 12111 in the first direction Z.

[0355] The bending segment 12111 is the part of the section 1211 bent relative to the pole piece body 11. Among them, the end of the section 1211 away from the pole piece body 11 is formed with a bending segment 12111.

[0356] In some possible designs, please refer to Figure 14 , and in combination with other drawings. The bending segment 12111 includes a first bending part 121111, and the first bending part 121111 is bent relative to the pole piece body 11 and arranged in a direction close to the winding axis L.

[0357] The first bending part 121111 refers to the part of the bending segment 12111 bent relative to the pole piece body 11 and arranged close to the winding axis L.

[0358] In some possible designs, please refer to Figure 14, and in conjunction with other drawings. The bending section 12111 includes a second bending portion 121112, which is arranged to bend away from the winding axis L with respect to the pole piece body 11.

[0359] The second bending portion 121112 refers to the part of the bending section 12111 arranged to bend away from the winding axis L with respect to the pole piece body 11.

[0360] In this way, the end region of the pole piece 1211 away from the pole piece body 11 in the first direction Z can be bent to form a relatively dense accumulation layer, so that the end region of the tab 12 away from the pole piece body 11 in the first direction Z forms an accumulation layer.

[0361] In some embodiments, please refer to Figure 14 , and in conjunction with other drawings. Each pole piece 1211 is provided with a bending section 12111 at one end in the first direction Z.

[0362] Each bending section 12111 of each pole piece 1211 can include a first bending portion 121111 and not include a second bending portion 121112, so that all pole pieces 1211 can be arranged to bend towards the winding axis L to achieve regular bending operation of the second tab winding portion 121b. Alternatively, each bending section 12111 of each pole piece 1211 can include a second bending portion 121112 and not include a first bending portion 121111, so that the second tab winding portion 121b can be bent. Alternatively, each pole piece 1211 can include a first bending portion 121111 and a second bending portion 121112, so that the second tab winding portion 121b can be bent. Alternatively, among the plurality of pole pieces 1211, a part of the bending sections 12111 of the pole pieces 1211 include the first bending portion 121111 or the second bending portion 121112, and the bending sections 12111 of the other part of the pole pieces 1211 include the first bending portion 121111 and the second bending portion 121112. Alternatively, among the plurality of pole pieces 1211, a part of the bending sections 12111 of the pole pieces 1211 include the first bending portion 121111, another part of the bending sections 12111 of the pole pieces 1211 include the second bending portion 121112, and the remaining part of the bending sections 12111 of the pole pieces 1211 include the first bending portion 121111 and the second bending portion 121112.

[0363] In this way, each pole piece 1211 of the tab 12 is arranged to bend, so that the end region of the tab 12 away from the pole piece body 11 in the first direction Z can be bent to form a relatively dense accumulation layer.

[0364] In some embodiments, please refer to Figure 14, and in conjunction with other drawings. The first bending portion 121111 is arranged to bend along the radial direction Y of the electrode assembly 10.

[0365] Specifically, in the radial direction Y of the electrode assembly 10, the first bending portion 121111 is arranged to bend towards the direction close to the winding axis L.

[0366] In some embodiments, as shown in Figure 14 , and in conjunction with other drawings. The second bending portion 121112 is arranged to bend along the radial direction Y of the electrode assembly 10.

[0367] Specifically, in the radial direction Y of the electrode assembly 10, the second bending portion 121112 is arranged to bend away from the winding axis L.

[0368] By adopting the above technical solution, the bending segment 12111 is arranged to bend along the radial direction Y, so that the tab 12 can be better bent to form a stacked layer.

[0369] In other embodiments, the first bending portion 121111 can be arranged to bend along a direction intersecting the radial direction Y, and the second bending portion 121112 can also be arranged to bend along a direction intersecting the radial direction Y.

[0370] In some embodiments, please refer to Figure 14 , and in conjunction with other drawings. The bending segment 12111 includes at least one first bending portion 121111 and at least one second bending portion 121112, and the first bending portion 121111 and the second bending portion 121112 are arranged alternately along the first direction Z.

[0371] In this way, the tab 12 can be bent away from the end region of the electrode piece main body 11 along the first direction Z, so as to be gathered and formed into a relatively dense stacked layer.

[0372] In some embodiments, please refer to Figure 12 , and in conjunction with other drawings. The two electrode pieces 1 include a positive electrode piece 1a and a negative electrode piece 1b. The tab 12 of the positive electrode piece 1a is not coated with an active material layer 111, and / or the tab 12 of the negative electrode piece 1b is not coated with an active material layer 111. In the first direction Z, the tab 12 is provided with an insulating layer 13 close to the end region of the electrode piece main body 11, and the section 1211 is located on the side of the insulating layer 13 away from the electrode piece main body 11.

[0373] The insulating layer 13 refers to a structure layer with insulating properties, which can be an insulating coating, insulating glue, etc.

[0374] Specifically, at least part of the insulating layer 13 is arranged on the end region of the tab winding portion 121 close to the tab main body 11 in the first direction Z. Among them, the tab winding portion 121 can be completely provided with the insulating layer 13; or the end region of the tab winding portion 121 away from the tab main body 11 in the first direction Z can not be provided with the insulating layer 13.

[0375] Specifically, when the tab 12 includes the tab ring portion 122 as mentioned above, part of the insulating layer 13 can be arranged on the end region of the tab ring portion 122 close to the tab main body 11 in the first direction Z. Among them, the tab ring portion 122 can be completely provided with the insulating layer 13; or the end region of the tab ring portion 122 away from the tab main body 11 in the first direction Z can not be provided with the insulating layer 13.

[0376] Among them, as shown in Figure 12 , the insulating layer 13 can be arranged only on the end region of the tab winding portion 121 close to the tab main body 11, and not arranged on the first tab main body 11a. Based on this, the side edge of the insulating layer 13 close to the first tab main body 11a in the first direction Z is the boundary between the positive tab 12a and the first tab main body 11a. Or, part of the insulating layer 13 is arranged on the end region of the first tab main body 11a close to the positive tab 12a in the first direction Z. When the end region of the first tab main body 11a close to the positive tab 12a is not coated with the active material layer 111, the part of the first tab main body 11a not coated with the active material layer 111 needs to be provided with the insulating layer 13.

[0377] In some possible designs, as shown in Figure 12 , in the first direction Z, the cutout 1211 of the positive tab 12a is arranged on the side of the insulating layer 13 away from the first tab main body 11a. Based on this, the second groove bottom surface 107 of the second cut-off groove 106 is arranged on the side of the insulating layer 13 away from the first tab main body 11a in the first direction Z. Or, in another possible design, in the first direction Z, the cutout 1211 of the positive tab 12a is arranged on the side of the insulating layer 13 away from the first tab main body 11a. And, the second groove bottom surface 107 of the second cut-off groove 106 coincides with the side edge of the insulating layer 13 away from the first tab main body 11a in the first direction Z.

[0378] In this way, the positive tab 1a is provided with the insulating layer 13, so that the short circuit problem between the positive tab 1a and the negative tab 1b can be effectively improved.

[0379] In some embodiments, please refer to Figure 15 and Figure 16, and in combination with other drawings. The at least one tab winding portion 121 includes the transition connection portion 1212 and the above-mentioned segment 1211, and the tab main body 11, the transition connection portion 1212 and the segment 1211 are sequentially arranged along the 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 the second cutting groove 106. The second groove bottom surface 107 of the second cutting groove 106 is formed on the side edge of the transition connection portion 1212 for connecting the segments 1211.

[0380] It can be understood that the tab winding portion 121 includes the transition connection portion 1212 and a plurality of segments 1211, and the plurality of segments 1211 are distributed on the transition connection portion 1212 along the winding direction W. Among them, the tab main body 11 is connected to one side of the transition connection portion 1212 along the first direction Z, and the segment 1211 is 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 segment 1211 along the first direction Z.

[0381] It can be understood that the second groove bottom surface 107 of the second cutting groove 106 is formed on the side edge of the transition connection portion 1212 close to the segment 1211 along the first direction Z, and specifically the second groove bottom surface 107 is the end surface of the tab ring portion 15 away from the tab main body 11.

[0382] By connecting the transition connection portion 1212 between the tab main body 11 and the segment 1211, on the one hand, the tab main body 11 and the segment 1211 are arranged apart along the first direction Z, and the tab main body 11 and the second cutting groove 106 are arranged apart along the first direction Z. In this way, in the process of cutting the tab winding portion 121 to form the second cutting groove 106 and the segment 1211, the tab main body 11 can be avoided to a certain extent to avoid being cut. And, it can solve the problem that the second groove bottom surface 107 of the second cutting groove 106 is formed on the side edge of the tab main body 11, which causes the tab main body 11 to be easily torn and damaged. On the other hand, the transition connection portion 1212 can block the segment 1211 to block the segment 1211 and the main body portion P of the electrode assembly 10, so as to improve the problem that the segment 1211 is inserted into the main body portion P after being bent, causing short circuit in the electrode assembly 10, and reduce the risk of short circuit.

[0383] It needs to be supplemented here that please refer to Figure 12 , and in combination with other drawings. In the positive electrode tab 1a, the insulating layer 13 is arranged on at least part of the transition connection portion 1212. Among them, in some possible designs, such as Figure 12As shown, the insulating layer 13 is arranged on a part of the transition connection portion 1212, so that the insulating layer 13 and the tab 1211 are spaced apart along the first direction Z. Alternatively, in some other possible designs, the insulating layer 13 completely covers the transition connection portion 1212, so that the insulating layer 13 coincides with the side edge of the transition connection portion 1212 away from the tab 1211 along the first direction Z.

[0384] In some embodiments, reference is made to Figure 12 , Figure 13 , 15 , Figure 16 , Figure 19 and Figure 20 , and in conjunction with other drawings. Among them, Figure 19 is an enlarged view of H in Figure 15 , Figure 20 is an enlarged view of I in Figure 15 . In Figure 19 and Figure 20 , the transition connection portion 1212 and the tab 1211 are divided by a dashed line. The size of the side edge of the tab 1211 for connecting the transition connection portion 1212 in the winding direction W of the electrode assembly 10 is H1, and the size of the transition connection portion 1212 and the tab 1211 in the first direction Z is H2, 0.01≤H2 / H1≤0.3.

[0385] The side edge of the tab 1211 for connecting the transition connection portion 1212 refers to the edge of the tab 1211 close to the side edge of the tab 1211 along the first direction Z, that is, the edge of the tab 1211 at the boundary between the tab 1211 and the transition connection portion 1212. The boundary between the tab 1211 and the transition connection portion 1212 is mainly based on the position of the first slot bottom surface 103, which can be specifically referred to Figure 12 , Figure 13 , Figure 16 , Figure 19 and Figure 20 for dividing the transition connection portion 1212 and the tab 1211. It can be understood that the side edge of the tab 1211 for connecting the transition connection portion 1212 is collinearly connected with the second slot bottom surface 107.

[0386] The size of the side edge of the tab 1211 for connecting the transition connection portion 1212 in the winding direction W of the electrode assembly 10 refers to the maximum size of the tab 1211 in the winding direction W, and also refers to the size of the side edge of the tab 1211 for connecting the transition connection portion 1212 in the length direction X of the tab 1 when the tab 1 is in an unfolded state, that is, the maximum size of the tab 1211 in the length direction X of the tab 1 when the tab 1 is in the unfolded state.

[0387] The sum of the dimension of the transition connection portion 1212 and the dimension of the tab 1211 in the first direction Z refers to the sum of the dimension of the transition connection portion 1212 in the first direction Z and the dimension of the tab 1211 in the first direction Z before the electrode assembly 10 is wound or in an unwound state, which is the maximum dimension of the tab 12 in the first direction Z.

[0388] 0.01≤H2 / H1≤0.3, and H2 / H1 can be 0.01, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, etc.

[0389] In this way, the tab 1211 has a large dimension in the winding direction W, which facilitates winding of the tab 1211 and ensures the structural integrity of the electrode assembly 10 to some extent and ensures the charge-discharge performance of the cylindrical battery cell 100 to some extent.

[0390] In some embodiments, please refer to Figure 16 , and in combination with other drawings. The dimension of the transition connection portion 1212 in the first direction Z is H3, and 0.1mm≤H3≤2mm.

[0391] The dimension of the transition connection portion 1212 in the first direction Z refers to the distance between the side edge of the tab 1211 close to the electrode tab body 11 and the side edge of the electrode tab body 11 close to the tab 1211 in the first direction Z.

[0392] 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.

[0393] In this way, on the basis of the second cut-off groove 106 formed in the tab winding portion 121, the transition connection portion 1212 has a suitable width in the first direction Z to block the tab 1211, which can improve the problem of the tab 1211 being bent and inserted into the body portion P.

[0394] In some embodiments, please refer to Figure 17 , and in combination with other drawings. Among the plurality of tab winding portions 121, the outermost tab winding portion 121 includes a plurality of the above-mentioned tabs 1211 in the winding direction W of the electrode assembly 10, and the tab 1211 closest to the winding end 105 is wound at least one turn.

[0395] Understandably, among the plurality of tabs 1211 of the outermost tab winding portion 121, the tab 1211 closest to the winding end 105 is wound at least one turn in the winding direction W.

[0396] The most proximal tab 1211 to the winding end 105 is the one farthest from the winding axis L.

[0397] The most outer tab winding portion 121 in the radial direction Y of the electrode assembly 10 can be, but is not limited to, the second tab winding portion 121b.

[0398] The number of turns of the tab 1211 refers to the number of layers of the tab layer of the tab 1211.

[0399] As an example, as shown in FIG. 1, the most proximal tab 1211 to the winding end 105 is wound multiple turns. Figure 16

[0400] By winding the most proximal tab 1211 to the winding end 105 at least one turn, the most proximal tab 1211 to the winding end 105 can better wrap the other tabs 1211, which can improve the internal short problem caused by the tabs 1211 everted and inserted into the body portion P, thereby reducing the risk of short circuit.

[0401] In some embodiments, please refer to FIG. 1, and in combination with other drawings. At least one tab winding portion 121 is provided with a plurality of second cutting grooves 106, and each second cutting groove 106 and each tab 1211 in the tab winding portion 121 are alternately arranged in the winding direction W of the electrode assembly 10. Figure 15

[0402] It can be understood that the number of tabs 1211 in the tab winding portion 121 is at least 3, so that the number of second cutting grooves 106 in the tab winding portion 121 is at least 2.

[0403] It can be understood that the plurality of second cutting grooves 106 are spaced apart on the tab winding portion 121 in the winding direction W, the plurality of tabs 1211 are sequentially arranged on the tab winding portion 121 in the winding direction W, and each second cutting groove 106 and each tab 1211 are alternately arranged in the winding direction W.

[0404] ​​By forming a plurality of second cut-off grooves 106 on the tab winding portion 121, the tab winding portion 121 can achieve a larger cutting-off ratio cutting-off effect, so that the part of the tab winding portion 14 where the second cut-off groove 106 is formed can be discharged through the pressure relief portion 22111 during the thermal runaway process, to achieve a higher efficiency directional pressure relief effect. And on this basis, the part of the tab winding portion 121 where the second cut-off groove 106 is formed is bent to form a stacking layer that is not too weak, which can effectively block the laser generated during the welding process, thereby achieving a protection effect on the separator 2. In addition, the plurality of second cut-off grooves 106 are provided, so that the cutting-off operation of the tab 12 can be adjusted according to the actual situation, so that the operation of cutting off the tab 12 to form the second cut-off groove 106 is very flexible.

[0405] In some embodiments, as shown in Figure 15 , and in conjunction with other drawings. Among the plurality of second cut-off grooves 106 of the tab winding portion 121, the size of each second cut-off groove 106 can be the same. For example, the size of each second cut-off groove 106 along the winding direction W is the same. Alternatively, among the plurality of second cut-off grooves 106 of the tab winding portion 121, the size of at least two second cut-off grooves 106 is different.

[0406] In some embodiments, as shown in Figure 15 , and in conjunction with other drawings. Among the plurality of second cut-off grooves 106 of the tab winding portion 121, the shape of each second cut-off groove 106 can be the same. Alternatively, among the plurality of second cut-off grooves 106 of the tab winding portion 121, the shape of at least two second cut-off grooves 106 can be different.

[0407] In some embodiments, as shown in Figure 15 , and in conjunction with other drawings. Among the plurality of cut pieces 1211 of the tab winding portion 121, the size of at least two cut pieces 1211 can be different. For example, as shown in Figure 15 , the size of the two cut pieces 1211 along the winding direction W is different. Alternatively, among the plurality of cut pieces 1211 of the tab winding portion 121, the size of each tab 12 can be the same.

[0408] Among the plurality of cut pieces 1211 of the tab winding portion 121, as shown in Figure 15 , the shape of each cut piece 1211 can be the same. Alternatively, among the plurality of cut pieces 1211 of the tab winding portion 121, the shape of at least two cut pieces 1211 can be different.

[0409] In some embodiments, please refer to Figure 15 and Figure 16 , and in conjunction with other drawings. In the first direction Z, the size of the cut piece 1211 along the winding direction W of the electrode assembly 10 shows a decreasing trend in the direction away from the tab body 11.

[0410] In the first direction Z, the tab 1211 can be tapered towards the direction away from the tab body 11 along one side of the winding direction W of the electrode assembly 10, or in the first direction Z, the tab 1211 can be tapered towards the direction away from the tab body 11 along both sides of the winding direction W of the electrode assembly 10, so that in the unfolded state of the tab 1, the tab 1211 is substantially trapezoidal. Based on this, in the first direction Z, the size of the tab 1211 along the winding direction W is gradually reduced towards the direction away from the tab body 11.

[0411] Correspondingly, in the first direction Z, the second cut-off groove 106 is gradually expanded towards the direction away from the tab body 11 along one side or both sides of the winding direction W, so that in the first direction Z, the size of the second cut-off groove 106 along the winding direction W is gradually increased towards the direction away from the tab body 11.

[0412] Correspondingly, in the first direction Z, the first cut-off groove 102 is gradually expanded towards the direction away from the tab body 11 along one side or both sides of the winding direction W, so that in the first direction Z, the size of the first cut-off groove 102 along the winding direction W is gradually increased towards the direction away from the tab body 11.

[0413] By gradually reducing the size of the tab 1211 along the winding direction W towards the direction away from the tab body 11 in the first direction Z, it helps to reduce the restraint of the accumulated layers formed by the bending of the end region of the tab 1211 away from the tab body 11, so as to help the part of the tab 1 with the second cut-off groove 106 to loosen up during the thermal runaway process and open the exhaust passage formed by the pressure relief part 2211 for discharge. And under the arrangement of the first cut-off groove 102, at least one tab winding part 14 is easy to loosen up from other tab winding parts 14 under the action of gas pressure or even through the pressure relief part 22111 for discharge. Based on this, it helps to improve the directional pressure relief efficiency.

[0414] In some embodiments, please refer to Figures 7 to 9 、 Figure 15 、 Figure 17 、 Figure 19 and Figure 20 , and in combination with other drawings. Among the plurality of tab winding parts 121, the innermost tab winding part 121 along the winding direction W of the electrode assembly 10 is provided with a first notch groove 108. The first notch groove 108 penetrates the winding starting end 104 along the winding direction W of the electrode assembly 10, and the first notch groove 108 penetrates the end face of the tab winding part 121 away from the tab body 11. In the projection plane perpendicular to the first direction Z, the orthographic projection of the third groove bottom surface 109 of the first notch groove 108 is located within the orthographic projection of the pressure relief part 22111.

[0415] The innermost tab winding part 121 is the tab winding part 121 closest to the winding start end 104, which can be the first tab winding part 121a described above, i.e., the first tab winding part 121a forms the winding start end 104, and the first tab winding part 121a is provided with the first notch groove 108. Correspondingly, the tab winding part 14 formed with the winding start end 104 and the first notch groove 108 can be the first tab winding part 14a.

[0416] 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 side groove wall of the first notch groove 108 along the first direction Z close to the tab body 11.

[0417] By locating the orthographic projection of the third groove bottom surface 109 of the first notch groove 108 within the orthographic projection of the pressure relief part 22111 on a projection plane perpendicular to the first direction Z, the tab winding part 14 formed with the first notch groove 108 (which can be the first tab winding part 14a) is also arranged opposite the pressure relief part 22111 along the first direction Z. In this way, the restraint effect of the tab winding part 14 formed with the first notch groove 108 can be reduced, which facilitates the tab winding part 14 formed with the first notch groove 108 to be discharged to the outside of the shell 20 through the pressure relief part 22111 during the thermal runaway process, thereby facilitating the improvement of the directional pressure relief efficiency of the cylindrical battery cell 100.

[0418] In some embodiments, please refer to Figures 7 to 9 , and in combination with other drawings. The cylindrical battery cell 100 further includes a current collecting member 30, at least part of which is arranged in the shell 20.

[0419] In some embodiments, please refer to Figures 7 to 9 , Figure 17 and Figure 19 , and in combination with other drawings. In the first direction Z, the tab winding part 121 has a winding start segment 12121 located at one end of the first notch groove 108 close to the tab body 11, and the third groove bottom surface 109 of the first notch groove 108 is the end surface of the winding start segment 12121 away from the tab body 11. The current collecting member 30 is welded to the part of the tab winding part 121 beyond the third groove bottom surface 109 in the direction away from the tab body 11, and is not welded to the winding start segment 12121.

[0420] The third groove bottom surface 109 is formed at the side edge of the winding start segment 12121 away from the tab body 11 along the first direction Z.

[0421] When the tab winding portion 121 closest to the winding start end 104 is formed with the tab segment 1211 and the second cut-off groove 106, in the first direction Z, the tab segment 1211 exceeds the third groove bottom surface 109 of the first cutaway groove 108 in a direction away from the tab body 11, specifically, exceeds the winding start segment 12121. The winding start segment 12121 and the adjacent tab segment 1211 together form the first cutaway groove 108.

[0422] When the tab winding portion 121 closest to the winding start end 104 includes the transition connection portion 1212, the winding start segment 12121 is part of the transition connection portion 1212 of the tab winding portion 121. Understandably, the transition connection portion 1212 of the tab winding portion 121 closest to the winding start end 104 can include the winding intermediate segment 12122 and the winding start segment 12121, the winding intermediate segment 12122 and the winding start segment 12121 are connected in sequence along the winding direction W of the electrode assembly 10, the winding intermediate segment 12122 and the winding start segment 12121 are both arranged at the side edge of the tab body 11 close to the tab 12 along the first direction Z, and the winding intermediate segment 12122 is connected between the tab body 11 and the tab segment 1211 along the first direction Z. When the tab winding portion 121 closest to the winding start end 104 does not include the transition connection portion 1212, the tab segment 1211 and the winding start segment 12121 are both arranged at the side edge of the tab body 11 close to the tab 12 along the first direction Z, the winding start segment 12121 and the tab segment 1211 are distributed in sequence along the winding direction W of the electrode assembly 10, and the size of the tab segment 1211 along the first direction Z is greater than the size of the winding start segment 12121 along the first direction Z.

[0423] The current collecting member 30 is welded to the part of the tab winding portion 121 exceeding the third groove bottom surface 109, specifically, the current collecting member 30 is welded to the tab segment 1211 of the tab winding portion 121 closest to the winding start end 104.

[0424] By locating the orthographic projection of the third groove bottom surface 109 within the orthographic projection of the pressure relief portion 22111 on the projection plane perpendicular to the first direction Z, the winding start segment 12121 and the pressure relief portion 22111 are oppositely arranged along the first direction Z. As an example, as shown in Figure 9 、 Figure 17 and Figure 18 the orthographic projection of the winding start segment 12121 is located within the outer contour of the orthographic projection of the pressure relief portion 22111 on the projection plane perpendicular to the first direction Z.

[0425] The part of the tab winding portion 121 beyond the third groove bottom surface 109 is welded to the current collecting member 30, and is not welded to the winding start segment 12121, so that the restraint of the part of the tab winding portion 14 in which the first notch groove 108 is formed is low, and the tab winding portion 14 in which the first notch groove 108 is formed is facilitated to be discharged through the pressure relief portion 22111 under the action of air pressure in the thermal runaway process of the cylindrical battery cell 100, so as to facilitate to improve the directional pressure relief efficiency of the cylindrical battery cell 100.

[0426] In some embodiments, reference is made to Figures 7 to 9 、 Figure 15 、 Figure 17 、 Figure 19 and Figure 20 , and in combination with other drawings. Among the plurality of tab winding portions 121, the outermost tab winding portion 121 is provided with a second notch groove 1010 along the winding direction W of the electrode assembly 10. The second notch groove 1010 penetrates the winding end 105 along the winding direction W of the electrode assembly 10, and penetrates the end surface of the tab 12 away from the tab body 11.

[0427] Among them, the outermost tab winding portion 121 is the tab winding portion 121 closest to the winding end 105, which can be the second tab winding portion 121b described above, that is, the second tab winding portion 121b forms the winding end 105, and the second tab winding portion 121b is provided with the second notch groove 1010. Correspondingly, the tab winding portion 14 formed with the winding end 105 and the second notch groove 1010 can be the second tab winding portion 14b.

[0428] In this way, the second notch groove 1010 can form a channel to facilitate exhaust. Moreover, the restraint of the tab winding portion 14 formed with the second notch groove 1010 is reduced, so as to facilitate the tab winding portion 14 formed with the second notch groove 1010 to loosen or even spray out from the pressure relief portion 22111 in the thermal runaway process. Thus, it is facilitated to improve the directional pressure relief efficiency of the cylindrical battery cell 100.

[0429] In some embodiments, reference is made to Figures 7 to 9 、 Figure 17 and Figure 20 , and in combination with other drawings. The tab winding portion 121 has a winding end segment 12123 at one end of the second notch groove 1010 close to the tab body 11, and the fourth groove bottom surface 1011 of the second notch groove 1010 is the end surface of the winding end segment 12123 away from the tab body 11. The part of the tab winding portion 121 beyond the fourth groove bottom surface 1011 in the direction away from the tab body 11 is welded to the current collecting member 30, and is not welded to the winding end segment 12123.

[0430] When the tab winding portion 121 closest to the winding end 105 is formed with the tab 1211 and the second cutout groove 106, in the first direction Z, the tab 1211 exceeds the fourth groove bottom surface 1011 of the second cutout groove 1010 in a direction away from the tab body 11, specifically, exceeds the winding end segment 12123. Wherein, the winding end segment 12123 and the adjacent tab 1211 surround to form the second cutout groove 1010.

[0431] Wherein, the fourth groove bottom surface 1011 is formed on a side edge of the winding end segment 12123 away from the tab body 11 along the first direction Z.

[0432] Wherein, when the tab winding portion 121 closest to the winding end 105 includes the transition connection portion 1212, the winding end segment 12123 is part of the transition connection portion 1212 of the tab winding portion 121. Understandably, the transition connection portion 1212 of the tab winding portion 121 closest to the winding end 105 can include the winding middle segment 12122 and the winding end segment 12123, the winding end segment 12123 and the winding middle segment 12122 are connected in turn along the winding direction W of the electrode assembly 10, the winding middle segment 12122 and the winding end segment 12123 are both located on a side edge of the tab body 11 close to the tab 12 along the first direction Z, and the winding middle segment 12122 is connected between the tab body 11 and the tab 1211 along the first direction Z. Specifically, in the winding direction W, the winding middle segment 12122 of each tab winding portion 121 is located between the winding start segment 12121 and the winding end segment 12123.

[0433] When the tab winding portion 121 closest to the winding end 105 does not include the transition connection portion 1212, the tab 1211 and the winding end segment 12123 are both located on a side edge of the tab body 11 close to the tab 12 along the first direction Z, the winding end segment 12123 and the tab 1211 are distributed in turn along the winding direction W of the electrode assembly 10, and the size of the tab 1211 along the first direction Z is greater than the size of the winding end segment 12123 along the first direction Z. Specifically, in the winding direction W, all the tabs 1211 are located between the winding start segment 12121 and the winding end segment 12123.

[0434] The current collecting member 30 is welded to the part of the tab winding portion 121 exceeding the fourth groove bottom surface 1011, specifically, the current collecting member 30 is welded to the tab 1211 of the tab winding portion 121 closest to the winding end 105.

[0435] 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.

[0436] In some embodiments, please refer to the following: Figure 4 , Figures 7 to 9 And in conjunction with 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, which is 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.

[0437] 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.

[0438] The weak point 22112 refers to a structurally weaker section on the outer casing 20, 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 outer casing 20. As an example, such as... Figure 6 As shown, the first end wall 221 may be provided with a groove, and the groove formed by the groove is the first groove 201. The groove is specifically provided between the pressure relief part 22111 and the first wall 2212, for example, the groove is provided on the end cap 22 of the outer shell 20.

[0439] The pressure relief portion 22111 refers to a portion on the shell 20 that can be opened to form an exhaust passage, and is part of the pressure relief mechanism 2211. Specifically, when the pressure value inside the shell 20 reaches a threshold value, at least part of the weak portion 22112 will break under the action of air pressure to disconnect the connection between the pressure relief portion 22111 and the first wall 2212, so that at least part of the pressure relief portion 22111 is opened to form an exhaust passage.

[0440] By adopting the above technical solution, the pressure relief portion 22111 is opened to form an exhaust passage when the pressure value inside the cylindrical battery cell 100 reaches a threshold value, thereby facilitating the release of the pole piece 1 to the outside of the shell 20 through the exhaust passage formed by the at least part of the pressure relief portion 22111 during the thermal runaway process.

[0441] In other embodiments, the shell 20 further comprises a first wall 2212 and a pressure relief mechanism 2211, and the first wall 2212 and the electrode assembly 10 are arranged opposite along a first direction Z. The first wall 2212 is fixedly connected to the pressure relief mechanism 2211, and the pressure relief mechanism 2211 is provided with a first groove 201 and a pressure relief portion 22111, and the pressure relief portion 22111 is located in the area surrounded by the first groove 201. The bottom of the first groove 201 is provided with a weak portion 22112, and the pressure relief portion 22111 is connected to the weak portion 22112. At least part of the weak portion 22112 is configured to be able to break when pressure relief occurs to open the pressure relief portion 22111.

[0442] It can be understood that the pressure relief mechanism 2211 comprises a pressure relief portion 22111 and a weak portion 22112. Specifically, the weak portion 22112 is arranged around the outer periphery of the pressure relief portion 22111, the first wall 2212 is arranged around 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 are arranged to form the above-mentioned first groove 201. Based on this, the first groove 201 is provided such that the thickness of the weak portion 22112 is less than the thickness of other positions of the pressure relief mechanism 2211, so that the structural strength of the weak portion 22112 is lower than that of other positions of the pressure relief mechanism 2211.

[0443] Wherein, the pressure relief mechanism 2211 is fixedly connected to the first wall 2212, which can be the weak portion 22112 of the pressure relief mechanism 2211 connected to the first wall 2212, or other parts of the pressure relief mechanism 2211 connected to the first wall 2212.

[0444] Wherein, the pressure relief mechanism 2211 can be fixedly connected to the first wall 2212 by welding or the like, so that the pressure relief mechanism 2211 and the first wall 2212 are separately arranged.

[0445] Wherein, the pressure relief mechanism 2211 and the first wall 2212 can constitute the above-mentioned first end wall 221.

[0446] The weak portion 22112 refers to a portion of the pressure relief mechanism 2211 that has relatively weak structural strength, and is one part of the pressure relief mechanism 2211. The structural strength of the weak portion 22112 is lower than the structural strength of other positions of the pressure relief mechanism 2211. As an example, the pressure relief mechanism 2211 can be provided with a notch, and the groove formed by the notch is the first recess 201. The notch is specifically provided around the outer periphery of the pressure relief portion 22111.

[0447] When the pressure value inside the shell 20 reaches the threshold value, the weak portion 22112 will break under the action of the gas pressure to disconnect the connection between the pressure relief portion 22111 and the first wall 2212, so that the pressure relief portion 22111 opens to form an exhaust passage.

[0448] By adopting the above technical solution, the pressure relief portion 22111 is facilitated to open to form an exhaust passage when the pressure value inside the cylindrical battery monomer 100 reaches the threshold value, so that the tab 1 is facilitated to be discharged to the outside of the shell 20 through the exhaust passage opened by the pressure relief portion 22111 under the action of the gas pressure.

[0449] When the above weak portion 22112 is directly connected with the first wall 2212, in 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 recess 201, and is also the outer contour of the orthographic projection of the weak portion 22112.

[0450] In some embodiments, please refer to Figure 4 , Figure 6 , Figure 7 and Figure 15 , and in combination with other drawings. In the projection plane perpendicular to the first direction Z, the outer contour of the orthographic projection of the pressure relief portion 22111 is circular.

[0451] Such an arrangement makes the exhaust passage opened by the pressure relief portion 22111 also substantially circular, and the electrode assembly 10 is substantially a cylindrical body, so that the tab 1 is facilitated to be discharged through the exhaust passage when thermal runaway occurs, thereby helping to improve the directional pressure relief effect of the cylindrical battery monomer 100.

[0452] In some embodiments, please refer to Figures 7 to 11 , Figures 15 to 18 , and in combination with other drawings. The tab 12 further includes a tab ring portion 122 connected between two tab winding portions 121 adjacent in the winding direction W of the electrode assembly 10, and the tab ring portion 122 and the two tab winding portions 121 adjacent in the winding direction W of the electrode assembly 10 surround to form the first cut-off groove 102.

[0453] It can be understood that the tab loop portion 122 and the tab winding portion 121 are divided into multiple parts by the tab 12, and the tab loop portion 122 is arranged around the outer periphery of the winding axis L. Among them, the tab loop portion 122 is arranged between and connected to the adjacent two tab winding portions 121. Specifically, in the radial direction Y, the tab loop portion 122 is located between the adjacent two tab winding portions 121; in the winding direction W, the tab loop portion 122 is located between and connected to the adjacent two tab winding portions 121. It can be understood that among all the tab layers of the tab 12, part of the tab layers are wound to form the tab winding portion 121, and the other part of the tab layers are wound to form the tab loop portion 122.

[0454] Correspondingly, the part of the pole piece 1 where the tab loop portion 122 is formed is the pole piece loop portion 15, and the pole piece loop portion 15 is arranged between and connected to the adjacent two pole piece winding portions 14. Specifically, in the radial direction Y, the pole piece loop portion 15 is located between the adjacent two pole piece winding portions 14; in the winding direction W, the pole piece loop portion 15 is located between and connected to the adjacent two pole piece winding portions 14. The pole piece loop portion 15 includes the above-mentioned main body loop portion 113 and the tab loop portion 122 arranged in the first direction Z, and the main body loop portion 113 is arranged between and connected to the adjacent two main body winding portions 112. It can be understood that among all the pole piece layers of the pole piece main body 11, part of the pole piece layers are wound to form the pole piece winding portion 14, and the other part of the pole piece layers are wound to form the pole piece loop portion 15.

[0455] It can be understood that in the first direction Z, the tab winding portion 121 is longer than the tab loop portion 122, so that the tab loop portion 122 can be arranged with the adjacent two pole piece winding portions 14 to form the first cut-off groove 102.

[0456] Among them, the first groove bottom surface 103 of the first cut-off groove 102 is formed on the side edge of the tab loop portion 122 away from the pole piece main body 11 in the first direction Z.

[0457] Among them, the number of turns of the first cut-off groove 102 is the number of turns of the tab loop portion 122, and is also the number of layers of the tab layers of the tab loop portion 122.

[0458] Among them, when the tab winding portion 121 is provided with the above-mentioned transition connection portion 1212, the tab loop portion 122 is connected between the adjacent two transition connection portions 1212 in the winding direction W, and specifically, the tab loop portion 122 is connected between the winding intermediate segments 12122 of the adjacent two transition connection portions 1212 in the winding direction W.

[0459] In the first direction Z, the first slot bottom surface 103 can protrude beyond the second slot bottom surface 107 in a direction away from the pole piece body 11. Alternatively, in the first direction Z, the second slot bottom surface 107 can protrude beyond the first slot bottom surface 103 in a direction away from the pole piece body 11. Alternatively, in the first direction Z, the first slot bottom surface 103 and the second slot bottom surface 107 can be flush.

[0460] In the positive pole piece 1a, the tab loop portion 122 can be completely provided with the insulating layer 13. Alternatively, the tab loop portion 122 can be provided with the insulating layer 13 only in part.

[0461] In this way, the tab loop portion 122 can block the tab winding portion 121, and the problem of the tab winding portion 121 being bent and inserted into the body portion P can be improved, thereby reducing the risk of short circuit.

[0462] In some embodiments, please refer to Figure 11 and Figure 16 , and in combination with other drawings. The size of the tab loop portion 122 in the first direction Z is H4, and 0.1mm≤H4≤2mm.

[0463] In this way, the size of the tab loop portion 122 in the first direction Z is H4, and 0.1mm≤H4≤2mm.

[0464] In this way, the size of the tab loop portion 122 in the first direction Z is H4, and 0.1mm≤H4≤2mm.

[0465] In some embodiments, please refer to Figure 7 and Figure 8 , Figure 21 and Figure 22 , and in combination with other drawings. In this way, Figure 21 is a projection schematic view of the electrode assembly 10 and the current collecting member 30 of the cylindrical battery cell 100 provided in some embodiments of the present application, specifically, the front projection of the electrode assembly 10 and the front projection of the current collecting member 30 on a projection plane perpendicular to the first direction Z. Figure 21 In this way, the size of the tab loop portion 122 in the first direction Z is H4, and 0.1mm≤H4≤2mm. Figure 22The projection schematic view of the electrode assembly 10 and the current collecting member 30 of the cylindrical battery cell 100 provided for other embodiments of the present application is specifically the front projection of the electrode assembly 10 and the front projection of the current collecting member 30 on the projection plane perpendicular to the first direction Z. Figure 22 The structure shown by the section line is the second welding portion 60, and the first arc line M3 and the second arc line M4 are both dashed lines. The cylindrical battery cell 100 further includes the current collecting member 30, at least a part of which is arranged in the shell 20. The current collecting member 30 is welded to the tab winding portion 121 to form the first welding portion 40. The current collecting member 30 is not welded to the tab ring portion 122.

[0466] The current collecting member 30 refers to a component with a conductive property, which is mainly used for welding with the tab 12 to achieve the current collecting effect of the electrode assembly 10. The current collecting member 30 can be an adapter structure between the current transmission end of the cylindrical battery cell 100 and the electrode assembly 10. Specifically, the current collecting member 30 is welded to the tab 12 to achieve the electrical connection between the current collecting member 30 and the electrode assembly 10, and the current collecting member 30 can also be electrically connected with the current transmission end, thereby achieving the electrical connection between the current transmission end and the electrode assembly 10.

[0467] The current collecting member 30 can be but is not limited to a current collecting disc.

[0468] The current transmission end of the cylindrical battery cell 100 refers to a component for transmitting the current of the cylindrical battery cell 100, which can be specifically used for outputting or inputting the current. The current transmission end can include the electrode terminal 50 referred to below, and can also include the shell 20. The current transmission end includes a positive current transmission end and a negative current transmission end.

[0469] The current collecting member 30 is welded to the tab 12, specifically the current collecting member 30 is welded to the tab winding portion 121 of the tab 12, that is, the current collecting member 30 is welded to the tab layer of the tab winding portion 121. The current collecting member 30 is welded to the tab winding portion 121, so that the tab winding portion 121 can achieve a certain self-binding effect through welding, thereby achieving a strong binding effect on the whole tab 1, to a certain extent, to guarantee the structural integrity of the electrode assembly 10 and facilitate the guarantee of the charge-discharge performance of the electrode assembly 10. When the tab winding portion 121 includes the above-mentioned section 1211, the current collecting member 30 is welded to the tab winding portion 121, specifically the section 1211 of the tab winding portion 121.

[0470] Correspondingly, the current collecting member 30 is not welded with the tab ring portion 122, so that the current collecting member 30 substantially does not play a role in binding the tab ring portion 122, and the self-binding effect of the tab ring portion 122 is weak, and the self-binding effect of the tab ring portion 15 is also weakened. The tab ring portion 122 can be spaced apart from the current collecting member 30 along the first direction Z, as shown in Figure 4 、 Figure 7 and Figure 8 indicated; or the tab ring portion 122 is in contact with the current collecting member 30.

[0471] Specifically, the current collecting member 30 and the electrode 12 are arranged along the first direction Z. That is, the current collecting member 30 is arranged between at least one wall of the shell 20 along the first direction Z and the electrode assembly 10. As an example, as shown in Figure 4 , the electrode assembly 10 is formed with the electrode 12 at both ends along the first direction Z, and the electrode assembly 10 is provided with the current collecting member 30 at both ends along the first direction Z, and the current collecting member 30 at each end is welded to the tab winding portion 121 of the electrode 12 at each end. As another example, the electrode assembly 10 is provided with the current collecting member 30 at one end along the first direction Z. It can be understood that the current collecting member 30 can be strictly distributed along the first direction Z with the electrode 12, and at least part of the electrode 12 can also be arranged in the current collecting member 30.

[0472] As shown in Figure 4 , the electrode assembly 10 is provided with the electrode 12 at both ends along the first direction Z, and the electrode assembly 10 is provided with the current collecting member 30 at both ends along the first direction Z, and the current collecting member 30 at each end is welded to the tab winding portion 121 of the electrode 12 at each end. Or, the electrode assembly 10 is provided with the current collecting member 30 at one end along the first direction Z.

[0473] The first welding portion 40 refers to a welding mark formed by welding the current collecting member 30 and the tab winding portion 121.

[0474] As an example, as shown in Figure 21 , in a projection plane perpendicular to the first direction Z, the orthographic projection of the first welding portion 40 is substantially circular and is arranged around the outer periphery of the central hole 101. As another example, as shown in Figure 22 , the number of the first welding portion 40 is multiple, and in a projection plane perpendicular to the first direction Z, the orthographic projection of the multiple first welding portions 40 is arranged along the circumferential direction E, and the orthographic projection of the multiple first welding portions 40 is arranged around the outer periphery of the central hole 101.

[0475] The current collecting member 30 can be welded with the first tab winding portion 121a to form the first welding portion 40; the current collecting member 30 can also be welded with the second tab winding portion 121b to form the first welding portion 40. As an example, as shown in Figure 4 , Figure 7 and Figure 8 As shown in FIG. 1, in the positive electrode tab 12a, the first welding portion 40 is arranged on the second tab winding portion 121b. In the negative electrode tab 12b, the first welding portion 40 is arranged on the first tab winding portion 121a.

[0476] By welding the tab winding portion 121 of the electrode tab 12 by the current collecting member 30 and not welding the tab ring portion 122 of the electrode tab 12, the self-binding effect of the tab ring portion 122 is weakened, and the self-binding effect of the tab piece ring portion 15 is also weakened. In this way, the mutual binding effect of the two adjacent tab winding portions 121 is weakened, and the mutual binding effect of the two adjacent tab piece winding portions 14 is also weakened. Thus, when the pressure value inside the shell 20 reaches a threshold value, the tab piece 1 is facilitated to loosen and even be discharged to the outside of the shell 20 through the pressure relief portion 22111 under the action of the air pressure, which helps the cylindrical battery monomer 100 to achieve an efficient directional pressure relief effect.

[0477] In addition, by welding the tab winding portion 121 by the current collecting member 30 and not welding the tab ring portion 122, the first welding mark and the first cut-off groove 102 are arranged along the radial direction Y. In this way, the current collecting member 30 and the electrode tab 12 are facilitated to achieve stable welding.

[0478] It should be noted that the circumferential direction E refers to the circumferential direction, and the circumferential direction E is substantially perpendicular to the first direction Z.

[0479] In some embodiments, please refer to Figure 7 、 Figure 8 、 Figures 21 to 22 , and other drawings. In the 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 end point M1 and a second projection end point M2, respectively. The first projection end point M1 is closer to the winding axis L parallel to the first direction Z than the second projection end point M2. The area between the first circular arc line M3 passing through the first projection end point M1 and surrounding the winding axis L and the second circular arc line M4 passing through the second projection end point M2 and surrounding the winding axis L is a first span area M5. 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, and in the tab winding portion 121, a second cut-off groove 106 is arranged between any two adjacent segments 1211 along the winding direction W of the electrode assembly 10. At least part of the second cut-off groove 106 forms a first group of grooves, and in the first group of grooves, the orthographic projection of the second groove bottom surface 107 of all the second cut-off grooves 106 is located within the first span area M5. The current collecting member 30 is welded to the segment 1211 to form the above-mentioned first welding portion 40.

[0480] It can be understood that, in the projection plane perpendicular to the first direction Z, the first projection end point M1 and the second projection end point M2 are respectively located at two ends of the orthographic projection of the first welding portion 40 along the radial direction Y, the first circular arc line M3 passes through the first projection end point M1, the second circular arc line M4 passes through the second projection end point M2, the first circular arc line M3 and the second circular arc line M4 are both arranged around the outer periphery of the winding axis L, the first circular arc line M3 and the second circular arc line M4 are arranged in a spaced manner along the radial direction Y, and the second circular arc line M4 is arranged around the outer periphery of the first circular arc line M3, so that the first circular arc line M3 and the second circular arc line M4 form a first spanning area M5 in a spaced manner, and the first spanning area M5 is substantially annular. Wherein, the first circular arc line M3 and the second circular arc line M4 are both arranged around the outer periphery of the central hole 101.

[0481] Wherein, when the number of the first welding portion 40 is multiple, in the projection plane perpendicular to the first direction Z, the multiple first welding portions 40 all have the first projection end point M1 and the second projection end point M2, and the first circular arc line M3 passes through the multiple first projection end points M1, and the second circular arc line M4 passes through the multiple second projection end points M2.

[0482] Wherein, the first circular arc line M3 and the second circular arc line M4 are both in the shape of a circular arc. As an example, as shown in Figure 21 and Figure 22 , the first circular arc line M3 and the second circular arc line M4 are both circular.

[0483] In the first group of grooves, the orthographic projection of the second groove bottom surface 107 of all the second cut-off grooves 106 is located within the first spanning area M5, which means that in the projection plane perpendicular to the first direction Z, the orthographic projection of the second groove bottom surface 107 of each second cut-off groove 106 is substantially located within the first spanning area M5, and specifically, in the projection plane perpendicular to the first direction Z, all the second cut-off grooves 106 whose orthographic projection of the second groove bottom surface 107 is substantially located within the first spanning area M5 constitute the first group of grooves. It can be understood that the part of the tab winding portion 121 where the first welding portion 40 is formed is provided with the above-mentioned second cut-off groove 106.

[0484] It needs to be supplemented that, in the projection plane perpendicular to the first direction Z, when the orthographic projection of part of the second groove bottom surface 107 of a certain second cut-off groove 106 is located within the first spanning area M5, it can be defined that the second groove bottom surface 107 of the second cut-off groove 106 is substantially located within the first spanning area 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.

[0485] In the first group of slots, the number of turns of the single second truncated slot 106 is ≤ 3.

[0486] In some possible designs, reference can be made to Figure 17 and Figure 18 together with other drawings. In the first group of slots, the number of turns of the single second truncated slot 106 is ≤ 3.

[0487] The number of turns of the single second truncated slot 106 refers to the number of layers of the tab layer of the single second truncated slot 106; or refers to the number of turns of the second slot bottom surface 107 of the single second truncated slot 106 along the winding direction W.

[0488] The number of turns of the single second truncated slot 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.

[0489] As an example, as shown in Figure 18 , the number of turns of the second truncated slot 106 shown in Figure 18 is less than 1 turn.

[0490] In some possible designs, reference can be made to Figure 17 and Figure 18 together with other drawings. In the first group of slots, the number of second truncated slots 106 opposite and connected along the radial direction Y of the electrode assembly 10 is ≤ 3.

[0491] It can be understood that, in the projection plane perpendicular to the first direction Z, the number of second truncated slots 106 opposite and connected along the radial direction Y is ≤ 3. In the projection plane perpendicular to the first direction Z, the number of second truncated slots 106 opposite and connected along the radial direction Y can be 3 or 2; or, any two second truncated slots 106 are not opposite and connected along the radial direction Y.

[0492] As an example, as shown in Figure 18 , the number of second truncated slots 106 opposite and connected along the radial direction Y can be 2.

[0493] By adopting the technical scheme, the part of the tab winding portion 121 where the first welding portion 40 is formed is provided with the second cutting groove 106, so that the stacking layer formed by bending the part of the tab winding portion 121 where the first welding portion 40 is formed is not too weak due to the second cutting groove 106, so that the part of the tab winding portion 121 where the first welding portion 40 is formed can bear the welding penetration of the current collecting member 30 and the tab 12, and the problem of laser penetrating the tab 12 to burn the separator 2 during welding of the current collecting member 30 and the tab 12 can be improved, so that the problem of short circuit of the electrode assembly 10 caused by welding of the current collecting member 30 and the tab 12 can be improved, and the risk of short circuit is reduced.

[0494] In some embodiments, please refer to Figure 4 , Figure 8 and Figure 23 , and in combination with other drawings. Among them, Figure 23 is a projection schematic diagram of the electrode assembly 10, the current collecting member 30 and the electrode terminal 50 of the cylindrical battery cell 100 provided by some embodiments of the present application, specifically, the front projection of the electrode assembly 10, the front projection of the current collecting member 30 and the front projection of the electrode terminal 50 on the projection plane perpendicular to the first direction Z. Figure 23 In the figure, the areas shown by the section lines are the first transverse area M5 and the second transverse area N5, respectively, and the first circular arc line M3, the second circular arc line M4, the third circular arc line N3 and the third circular arc line N3 are all dashed lines. The cylindrical battery cell 100 further comprises an electrode terminal 50 fixed to the shell 20. The electrode terminal 50 is welded to the current collecting member 30 to form a second welding portion 60.

[0495] The electrode terminal 50 refers to a component with conductive performance, and the electrode terminal 50 serves as a current transmission end of the cylindrical battery cell 100 for transmitting current. Among them, the electrode terminal 50 can be but is not limited to a pole.

[0496] The electrode terminal 50 can be welded with the current collecting member 30 welded to the positive tab 12a, or can be welded with the current collecting member 30 welded to the negative tab 12b.

[0497] Among them, the number of electrode terminals 50 can be one. As an example, as shown in Figure 4 , the electrode terminal 50 is installed on the wall of one end of the shell 20 along the first direction Z, the current collecting member 30 is provided at the end of the electrode assembly 10 close to the electrode terminal 50 along the first direction Z, the current collecting member 30 and the tab 12 at the end are welded, and the current collecting member 30 and the electrode terminal 50 are welded.

[0498] Alternatively, the number of the electrode terminals 50 can be two, and the two electrode terminals 50 are a positive electrode terminal 50 and a negative electrode terminal 50, respectively. The positive electrode terminal 50 and the negative electrode terminal 50 can be arranged at one end of the housing 20, or can be arranged at two ends of the housing 20, respectively. As an example, the electrode terminals 50 are arranged on the walls of the two ends of the housing 20 along the first direction Z, and the electrode assembly 10 is provided with the tabs 12 and the current collecting members 30 at the two ends along the first direction Z. In the first direction Z, the tabs 12 and the corresponding current collecting members 30 at each end are welded, and the electrode terminals 50 and the corresponding current collecting members 30 are welded.

[0499] The electrode terminals 50 are fixed to the housing 20. Specifically, as shown in Figure 4 , the electrode terminals 50 can be arranged on the shell 21 of the housing 20. The electrode terminals 50 can also be arranged on the end cover 22 of the housing 20.

[0500] When the number of the electrode terminals 50 is two, the two electrode terminals 50 can be arranged on the shell 21 at the same time; or the two electrode terminals 50 can be arranged on the end cover 22 at the same time; or one of the two electrode terminals 50 is arranged on the shell 21, and the other is arranged on the end cover 22.

[0501] The electrode terminals 50 are welded to the current collecting members 30, and the current collecting members 30 are welded to the tab winding portions 121, so that the electrode terminals 50 can be electrically connected to the electrode assembly 10.

[0502] The second welding portion 60 refers to a welding mark formed by welding the electrode terminal 50 and the current collecting member 30. In the radial direction Y, the second welding portion 60 is arranged apart from the first cutout groove 102.

[0503] As an example, as shown in Figure 23 , in the projection plane perpendicular to the first direction Z, the orthographic projection of the second welding portion 60 is substantially circular and is arranged around the outer periphery of the central hole 101. As another example, the number of the second welding portions 60 is multiple, and in the projection plane perpendicular to the first direction Z, the orthographic projections of the multiple second welding portions 60 are arranged apart along the circumferential direction E, and the orthographic projections of the multiple second welding portions 60 are collectively arranged around the outer periphery of the central hole 101.

[0504] In this way, the electrical connection between the electrode terminals 50 and the electrode assembly 10 can be achieved.

[0505] In some embodiments, please refer to Figure 4 , Figure 8 and Figure 23, and in combination with other drawings. In the projection plane perpendicular to the first direction Z, two ends of the front projection of the second welding portion 60 have a third projection end point N1 and a fourth projection end point N2, respectively, the third projection end point N1 is closer to the winding axis L parallel to the first direction Z than the fourth projection end point N2, and the area between a third circular arc line N3 passing through the third projection end point N1 and arranged around the winding axis L and a fourth circular arc line N4 passing through the fourth projection end point N2 and arranged around the winding axis L is a second span area N5. 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, and in the tab winding portion 121, a second cutting groove 106 is arranged between any two adjacent segments 1211 along the winding direction W of the electrode assembly 10. At least part of the second cutting groove 106 forms a second group of grooves, in which the front projection of the second groove bottom surface 107 of all the second cutting grooves 106 is located within the second span area N5.

[0506] It can be understood that, in the projection plane perpendicular to the first direction Z, the third projection end point N1 and the fourth projection end point N2 are respectively arranged at the two ends of the front projection of the second welding portion 60 along the radial direction Y, the third circular arc line N3 passes through the third projection end point N1, the fourth circular arc line N4 passes through the fourth projection end point N2, the third circular arc line N3 and the fourth circular arc line N4 are both arranged around the outer periphery of the winding axis L, the third circular arc line N3 and the fourth circular arc line N4 are arranged in a spaced manner along the radial direction Y, the fourth circular arc line N4 is arranged around the outer periphery of the third circular arc line N3, so that the third circular arc line N3 and the fourth circular arc line N4 are spaced to form the second span area N5, and the second span area N5 is substantially annular. Wherein, the third circular arc line N3 and the fourth circular arc line N4 are both arranged around the outer periphery of the center hole 101.

[0507] Wherein, when the number of the second welding portion 60 is multiple, in the projection plane perpendicular to the first direction Z, the multiple second welding portions 60 all have the third projection end point N1 and the fourth projection end point N2, and the third circular arc line N3 passes through the multiple third projection end points N1, and the fourth circular arc line N4 passes through the multiple fourth projection end points N2.

[0508] Wherein, the third circular arc line N3 and the fourth circular arc line N4 are both in the shape of a circular arc. As an example, as shown in Figure 23 , the third circular arc line N3 and the fourth circular arc line N4 are both circular.

[0509] In the second group of grooves, the orthographic projection of the second groove bottom surface 107 of all the second truncated grooves 106 within the second span area N5 means that the orthographic projection of the second groove bottom surface 107 of each second truncated groove 106 is substantially within the second span area N5 in the projection plane perpendicular to the first direction Z. Specifically, all the second truncated grooves 106 whose orthographic projection of the second groove bottom surface 107 is substantially within the second span area N5 in the projection plane perpendicular to the first direction Z constitute the second group of grooves. Understandably, the portion of the tab winding portion 121 where the second welding portion 60 is formed is provided with the above-mentioned second truncated groove 106.

[0510] It needs to be added that, in the projection plane perpendicular to the first direction Z, when the orthographic projection of part of the second groove bottom surface 107 of a certain second truncated groove 106 is within the second span area N5, it can be defined that the second groove bottom surface 107 of the second truncated groove 106 is substantially within the second span area N5, and the second truncated groove 106 is defined as one of the second truncated grooves 106 in the second group of grooves.

[0511] Wherein, when the second welding portion 60 is formed on the first tab winding portion 121a, the second group of grooves is provided on the first tab winding portion 121a. Or, when the second welding portion 60 is formed on the second tab winding portion 121b, the second group of grooves is provided on the second tab winding portion 121b. When the first tab winding portion 121a and the second tab winding portion 121b are both provided with the second welding portion 60, the second group of grooves can be provided on the first tab winding portion 121a; can be provided on the second tab winding portion 121b; or part of them can be provided on the first tab winding portion 121a, and the other part can be provided on the second tab winding portion 121b.

[0512] As an example, as shown in Figure 4 , Figure 8 and Figure 23 , in the radial direction Y, the first welding portion 40 and the second welding portion 60 are arranged at intervals, and the first welding portion 40 is arranged on the outer side of the second welding portion 60. Based on this, in the radial direction Y, the first group of grooves is arranged on the outer side of the second group of grooves.

[0513] As an example, as shown in Figure 4 and Figure 8 , the second welding portion 60 is arranged on the first tab winding portion 121a, and the second group of grooves is arranged on the first tab winding portion 121a.

[0514] In some possible designs, please refer to Figure 4 , Figure 8 , Figure 17 , Figure 18 and Figure 23 , and combine with other drawings. In the second group of grooves, the number of turns of a single second truncated groove 106 is ≤3.

[0515] 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.

[0516] 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.

[0517] As an example, such as Figure 18 As shown, Figure 18 The second cut-off groove 106 shown has less than one turn.

[0518] Please refer to the following in some possible designs. Figure 4 , Figure 8 , Figure 17 , Figure 18 and Figure 23 And in conjunction with other accompanying drawings. In the second 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.

[0519] 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.

[0520] As an example, such as Figure 18 As shown, the number of second cut-off grooves 106 that are opposite and connected along the radial Y direction can be two.

[0521] 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.

[0522] In some embodiments, please refer to the following: Figure 4 , Figure 7 and Figure 8, and in conjunction with other drawings. In the radial direction Y of the electrode assembly 10, the first weld 40 is disposed outside the first notch groove 108.

[0523] By disposing the first weld 40 outside the first notch groove 108 in the radial direction Y of the electrode assembly 10, the accumulation layer formed by the bending of the portion of the tab winding portion 121 where the first weld 40 is formed will not be excessively weak due to the provision of the first notch groove 108, so that the portion of the tab winding portion 121 where the first weld 40 is formed can bear the weld penetration of the current collector member 30 and the tab 12, and the problem of the laser penetrating the tab 12 to burn the separator 2 during the welding of the current collector member 30 and the tab 12 can be improved.

[0524] In some embodiments, please refer to Figure 4 and Figure 8 , and in conjunction with other drawings. In the radial direction Y of the electrode assembly 10, the second weld 60 is disposed outside the first notch groove 108.

[0525] By disposing the second weld 60 outside the first notch groove 108 in the radial direction Y of the electrode assembly 10, the accumulation layer formed by the bending of the portion of the tab winding portion 121 where the second weld 60 is formed will not be excessively weak due to the provision of the first notch groove 108, so that the portion of the tab winding portion 121 where the second weld 60 is formed can bear the weld penetration of the current collector member 30 and the electrode terminal 50, and the problem of the laser penetrating the tab 12 to burn the separator 2 during the welding of the current collector member 30 and the electrode terminal 50 can be improved.

[0526] In the above, the problem of the laser penetrating the tab 12 to burn the separator 2 during the welding can be improved, so that the problem of the short circuit of the electrode assembly 10 can be improved, and the risk of short circuit can be reduced.

[0527] In some embodiments, please refer to Figure 4 , Figure 7 and Figure 8 , and in conjunction with other drawings. In the radial direction Y of the electrode assembly 10, the second notch groove 1010 is located outside the first weld 40.

[0528] By disposing the second notch groove 1010 outside the first weld 40 in the radial direction Y of the electrode assembly 10, the accumulation layer formed by the bending of the portion of the tab winding portion 121 where the first weld 40 is formed will not be excessively weak due to the provision of the second notch groove 1010, so that the portion of the tab winding portion 121 where the first weld 40 is formed can bear the weld penetration of the current collector member 30 and the tab 12, and the problem of the laser penetrating the tab 12 to burn the separator 2 during the welding of the current collector member 30 and the tab 12 can be improved.

[0529] In some embodiments, please refer to Figure 4 and Figure 8 , and in conjunction with other drawings. In the radial direction Y of the electrode assembly 10, the second notch groove 1010 is located outside the second welding portion 60.

[0530] By locating the second notch groove 1010 outside the second welding portion 60 in the radial direction Y of the electrode assembly 10, the portion of the tab winding portion 121 formed with the second welding portion 60 will not be too weak due to the bending of the portion of the tab winding portion 121 formed with the second welding portion 60, so that the portion of the tab winding portion 121 formed with the second welding portion 60 can bear the welding penetration of the current collector 30 and the electrode terminal 50, and the problem of the laser penetrating the tab 12 and burning the separator 2 during the welding of the current collector 30 and the electrode terminal 50 can be improved.

[0531] Therefore, the problem of the laser penetrating the tab 12 and burning the separator 2 during the welding can be improved, so that the short circuit problem of the electrode assembly 10 can be improved, and the risk of short circuit can be reduced.

[0532] In some embodiments, please refer to Figure 4 , Figure 7 and Figure 8 , and in conjunction with other drawings. Both of the two tabs 1 include a tab body 11 and a tab 12, wherein the tab 12 of one of the tabs 1 is a first tab, and the tab 12 of the other tab 1 is a second tab. The first tab and the second tab are respectively arranged at two ends of the electrode assembly 10 in the first direction Z. Both of the first tab and the second tab include the above-mentioned tab winding portion 121. In the first direction Z, both ends of the electrode assembly 10 are provided with a current collector 30, and the current collectors 30 located at both ends of the electrode assembly 10 are respectively a first current collector 30a and a second current collector 30b.

[0533] Among them, the first tab can be a positive tab 12a, and the second tab can be a negative tab 12b. The first tab can also be a negative tab 12b, and the second tab can be a positive tab 12a.

[0534] The first current collector 30a is welded to the tab winding portion 121 of the first tab to form the above-mentioned first welding portion 40. The second current collector 30b is welded to the tab winding portion 121 of the second tab to form the above-mentioned first welding portion 40. It can be understood that both of the first tab and the second tab are formed with the first welding portion 40.

[0535] It is to be noted that the current collecting members 30 located at the two ends of the electrode assembly 10 are respectively a first current collecting member 30a and a second current collecting member 30b, which means that the first current collecting member 30a and the second current collecting member 30b are located at the two ends of the electrode assembly 10 in the first direction Z, i.e. the first current collecting member 30a and the second current collecting member 30b are located at the two ends of the main part of the electrode assembly 10. The first current collecting member 30a and the second current collecting member 30b can be strictly arranged at the two ends of the electrode assembly 10 along the first direction Z, and the tab 12 of the electrode assembly 10 can also be partially arranged in the first current collecting member 30a and the second current collecting member 30b and welded to the first current collecting member 30a and the second current collecting member 30b, respectively.

[0536] In some embodiments, reference is made to Figure 4 , Figure 7 and Figure 8 together with other drawings. The shell 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 arranged at the two ends of the side wall 212 along the first direction Z, and the electrode terminal 50 is arranged on the second end wall 211. The first current collecting member 30a is welded to the tab winding part 121 of the first tab and is electrically connected to the electrode terminal 50. The second current collecting member 30b is welded to the tab winding part 121 of the second tab and is electrically connected to the side wall 212.

[0537] The solid wall of one end of the shell 20 along the first direction Z is the first end wall 221, and the solid wall of the other end of the shell 20 along the first direction Z is the second end wall 211. In the first direction Z, the side wall 212 is arranged 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.

[0538] The first end wall 221 can be a part of the shell 21; or, as shown in Figure 4 and Figure 7 , the first end wall 221 can be at least part of the end cover 22.

[0539] The second end wall 211 can be at least part of the end cover 22; or, as shown in Figure 4 and Figure 8 , the second end wall 211 can be a part of the shell 21.

[0540] As shown in Figure 4 , Figure 7 and Figure 8 , the side wall 212 is a part of the shell 21, and the side wall 212 has a conductive property.

[0541] The first end wall 221, the second end wall 211 and the side wall 212 define an internal environment of the cylindrical battery cell 100, and the electrode assembly 10, the first current collecting member 30a and the second current collecting member 30b are all arranged in the internal environment defined by the first end wall 221, the second end wall 211 and the side wall 212.

[0542] The first tab is electrically connected with the first current collecting member 30a, and the first current collecting member 30a is electrically connected with the electrode terminal 50, so that the first tab is electrically connected with the electrode terminal 50 through the first current collecting member 30a. In the first direction Z, the first current collecting member 30a can be arranged between the first tab and the second end wall 211.

[0543] The second tab is electrically connected with the second current collecting member 30b, and the second current collecting member 30b is electrically connected with the side wall 212, so that the second tab is electrically connected with the side wall 212 through the second current collecting member 30b. In the first direction Z, the second current collecting member 30b can be arranged between the second tab and the first end wall 221.

[0544] The first current collecting member 30a is welded with the tab winding part 121 of the first tab, so that the first current collecting member 30a and the first tab are electrically connected. The second current collecting member 30b is welded with the tab winding part 121 of the second tab, so that the second current collecting member 30b and the second tab are electrically connected.

[0545] The first current collecting member 30a can be but not limited to welded with the electrode terminal 50, so that the first current collecting member 30a and the electrode terminal 50 are electrically connected.

[0546] The second current collecting member 30b can be directly contacted with the side wall 212, so that the second current collecting member 30b and the side wall 212 are electrically connected. As an example, the second current collecting member 30b and the side wall 212 are welded. Alternatively, other intermediate components can be arranged between the second current collecting member 30b and the side wall 212, so that the second current collecting member 30b and the side wall 212 are electrically connected. As an example, the intermediate component is the first end wall 221, the first end wall 221 has a conductive property, the second current collecting member 30b is welded with the first end wall 221, and the first end wall 221 is welded with the side wall 212.

[0547] In some possible designs, the first end wall 221 can have a conductive property, and the side wall 212 can be electrically connected with the first end wall 221. For example, the side wall 212 is a part of the shell 21, and the first end wall 221 is at least part of the end cover 22. The first end wall 221 and the side wall 212 are welded, specifically, the first wall 2212 of the first end wall 221 and the side wall 212 are welded, so that the side wall 212 and the first end wall 221 are electrically connected.

[0548] In some possible designs, the second end wall 211 can have an electrically conductive property, and the side wall 212 can be electrically connected with the second end wall 211. For example, the second end wall 211 and the side wall 212 are two parts of the shell 21, and the second end wall 211 and the shell 21 are integrally formed to electrically connect the side wall 212 and the second end wall 211. In this case, the second end wall 211 is insulated from the electrode terminal 50, for example, an insulating member such as insulating glue or plastic is arranged between the second end wall 211 and the electrode terminal 50.

[0549] By adopting the technical solutions described above, at least one of the side wall 212, the first end wall 221, and the second end wall 211 can serve as one of the current transmission ends of the cylindrical battery cell 100, and the electrode terminal 50 serves as the other current transmission end of the cylindrical battery cell 100. That is, the electrode terminal 50 and the shell 20 can serve as the two current transmission ends of the cylindrical battery cell 100.

[0550] When the second end wall 211 and the electrode terminal 50 serve as the two current transmission ends of the cylindrical battery cell 100 respectively, the two current transmission ends of the cylindrical battery cell 100 can be located at the same end, which facilitates the assembly process of assembling the cylindrical battery cell 100 into a battery device 1000 and improves the efficiency of assembling a plurality of cylindrical battery cells 100 into a group.

[0551] In some embodiments, refer to Figure 4 and Figure 7 , and combine with other drawings. The second current collecting member 30b is welded to the first end wall 221, and the side wall 212 is electrically connected with the first end wall 221.

[0552] It can be understood that the first end wall 221 and the side wall 212 both have an electrically conductive property. The second current collecting member 30b can be but is not limited to welded to the first end wall 221, so that the second current collecting member 30b and the first end wall 221 are electrically connected. The side wall 212 and the first end wall 221 can be electrically connected by welding or other methods, so that the second current collecting member 30b and the side wall 212 are electrically connected.

[0553] In this way, the second current collecting member 30b and the side wall 212 are indirectly electrically connected through the first end wall 221.

[0554] In some embodiments, refer to Figure 25 , and combine with other drawings. Figure 25 A partial cross-sectional view of the cylindrical battery cell 100 provided in another embodiment of the present application is shown. In the radial direction Y of the electrode assembly 10, the side wall 212 protrudes inward to form a protruding portion 2121. The protruding portion 2121 and the electrode assembly 10 are distributed along the first direction Z. The second current collecting member 30b is welded to the side of the protruding portion 2121 close to the electrode assembly 10, as shown in FIG. 4. Figure 25 The second current collecting member 30b is welded to the side of the protrusion 2121 facing away from the electrode assembly 10.

[0555] It can be understood that the outer peripheral wall of the side wall 212 is provided with a rolling groove 202, and the rolling groove 202 is arranged such that the side wall 212 protrudes inward along the radial direction Y, so that the side wall 212 protrudes to form a protrusion 2121.

[0556] 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 collecting member 30b can be arranged between the electrode assembly 10 and the protrusion 2121, and welded to the side of the protrusion 2121 close to the electrode assembly 10; or in the first direction Z, the second current collecting member 30b can be arranged 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.

[0557] In this way, the second current collecting member 30b is directly electrically connected to the side wall 212.

[0558] In some embodiments, please refer to Figure 4 , Figure 7 and Figure 8 , and combine with other drawings. The first tab is a positive tab 12a, and the second tab is a negative tab 12b.

[0559] Based on this, the electrode terminal 50 is a positive electrode terminal 50, which is a positive current transmission end of the cylindrical battery cell 100; the positive electrode terminal 50 is electrically connected to the first current collecting member 30a, and the first current collecting member 30a is welded to the positive tab 12a. At least one of the first end wall 221, the second end wall 211 and the side wall 212 is a negative current transmission end of the cylindrical battery cell 100, and the second current collecting member 30b is welded to the negative tab 12b.

[0560] As an example, the materials of the side wall 212 and the first end wall 221 can both be steel.

[0561] 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 end of the cylindrical battery cell 100.

[0562] In some embodiments, please refer to Figure 4 and Figure 7 , and combine with other drawings. The first end wall 221 is provided with a pressure relief portion 22111.

[0563] It can be understood that the first end wall 221 comprises the first wall 2212 and the pressure relief mechanism 2211, the pressure relief mechanism 2211 is connected to the first wall 2212, and the pressure relief mechanism 2211 comprises a pressure relief part 22111. Wherein, the first wall 2212 and the pressure relief mechanism 2211 can be integrally formed; or, the first wall 2212 and the pressure relief mechanism 2211 can be separately arranged and connected.

[0564] By adopting the above technical scheme, the pressure relief part 22111 and the electrode terminal 50 are respectively arranged at two ends of the shell 20 along the first direction Z, so that the pressure relief part 22111 and the electrode terminal 50 are conveniently arranged, and the efficiency of assembling the plurality of cylindrical battery monomers 100 into a group is improved.

[0565] In some embodiments, please refer to Figure 4 、 Figure 7 and Figure 24 , and in combination with other drawings. Wherein, Figure 24 is a projection schematic view of the current collecting member 30 and the pressure relief part 22111 of the cylindrical battery monomer 100 provided by some embodiments of the present application, specifically, the front projection of the pressure relief part 22111 and the front projection of the current collecting member 30 on the projection plane perpendicular to the first direction Z. Figure 24 In the figure, the outer contour of the pressure relief part 22111 is a dashed line. The current collecting member 30 is provided with an exhaust through hole 301 extending along the first direction Z, and the exhaust through hole 301 is oppositely arranged with the pressure relief part 22111 along the first direction Z. The current collecting member 30 is provided with a plurality of guide parts 32, and the plurality of guide parts 32 are arranged around the outer periphery of the exhaust through hole 301.

[0566] The current collecting member 30 is provided with the exhaust through hole 301 extending along the first direction Z, which means that the exhaust through hole 301 penetrates the current collecting member 30 along the first direction Z.

[0567] The exhaust through hole 301 is oppositely arranged with the pressure relief part 22111 along the first direction Z, which means that at least part of the exhaust through hole 301 and the pressure relief part 22111 are oppositely arranged along the first direction Z. Based on this, when the pressure relief part 22111 opens to form an exhaust passage when the pressure value inside the shell 20 reaches the threshold value, the exhaust through hole 301 and the exhaust passage can be oppositely and continuously arranged along the first direction Z.

[0568] The guide part 32 refers to a structure on the current collecting member 30 for deforming and folding the position of the current collecting member 30 close to the exhaust through hole 301, so as to increase the exhaust through hole 301. Specifically, the current collecting member 30 can be cracked from the guide part 32 to expand the exhaust area of the exhaust through hole 301.

[0569] The plurality of guide parts 32 are circumferentially spaced apart and collectively surround the outer periphery of the exhaust through hole 301.

[0570] The first current collecting member 30a can be provided with the exhaust hole 301 and the guide portion 32. The second current collecting member 30b can also be provided with the exhaust hole 301 and the guide portion 32.

[0571] By adopting the above technical solutions, when the pressure value inside the shell 20 reaches the threshold value in the process of thermal runaway of the cylindrical battery cell 100, the pressure relief portion 22111 can be opened and an exhaust passage is formed under the action of the air pressure, and the guide portion 32 can also deform the part of the current collecting member 30 close to the exhaust hole 301 towards the pressure relief portion 22111 under the action of the air pressure, and the guide portion 32 is opened, so that the hole diameter of the exhaust hole 301 gradually increases. In this way, the jellyroll 14 is facilitated to move towards the pressure relief portion 22111 to be sequentially discharged to the outside of the shell 20 through the exhaust hole 301 and the exhaust passage. In this way, the directional pressure relief efficiency of the cylindrical battery cell 100 is improved.

[0572] In some embodiments, please refer to Figure 4 , Figure 6 and Figure 20 , and in combination with other drawings. In the projection plane perpendicular to the first direction Z, the front projection of the exhaust hole 301 is located within the front projection of the pressure relief portion 22111.

[0573] In some embodiments, please refer to Figure 4 , Figure 7 and Figure 24 , and in combination with other drawings. In the projection plane perpendicular to the first direction Z, along the radial direction Y of the electrode assembly 10, the front projection of the end of the guide portion 32 away from the exhaust hole 301 is located outside the outer contour of the front projection of the pressure relief portion 22111. Alternatively, in the projection plane perpendicular to the first direction Z, along the radial direction Y of the electrode assembly 10, the front projection of the end of the guide portion 32 away from the exhaust hole 301 coincides with the outer contour of the front projection of the pressure relief portion 22111.

[0574] The pressure relief mechanism 2211 includes the pressure relief portion 22111, and is provided with a first groove 201 surrounding the outer periphery of the pressure relief portion 22111. In the projection plane perpendicular to the first direction Z, the outer contour of the front projection of the pressure relief portion 22111 refers to the inner contour of the front projection of the first groove 201, that is, the joint position of the front projection of the pressure relief portion 22111 and the front projection of the first groove 201.

[0575] It can be understood that the guide portion 32 is arranged to extend substantially along the radial direction Y. Specifically, in the radial direction Y, the guide portion 32 extends from the exhaust hole 301 to a direction away from the exhaust hole 301. Wherein, in the radial direction Y, the end of the guide portion 32 away from the exhaust hole 301 is the first edge 321. Wherein, as Figure 24As shown, the orthographic projection of the first edge 321 is located outside the outer contour of the orthographic projection of the pressure relief portion 22111 in the projection plane perpendicular to the first direction Z; or, the orthographic projection of the first edge 321 coincides with the outer contour of the orthographic projection of the pressure relief portion 22111 in the projection plane perpendicular to the first direction Z.

[0576] By adopting the above technical solution, the guide portion 32 can be disconnected under the action of air pressure, so that the current collecting member 30 can be deformed and turned open toward the pressure relief portion 22111, and the hole diameter of the exhaust passage hole 301 can be enlarged to a large extent. In this way, when the pole piece winding portion 14 is opened to form an exhaust passage to discharge to the outside of the shell 20 through the pressure relief portion 22111 during the thermal runaway process of the cylindrical battery cell 100, the current collecting member 30 can reduce the hindering effect on the pole piece 1, which helps to improve the efficiency of the pole piece 1 through the exhaust passage, so as to improve the directional pressure relief efficiency of the cylindrical battery cell 100.

[0577] In some embodiments, the guide portion 32 includes a through hole penetrating through the current collecting member 30 along the first direction Z.

[0578] In some embodiments, the guide portion 32 includes a second groove not penetrating through the current collecting member 30 along the first direction Z.

[0579] As can be understood, the current collecting member 30 includes the current collecting body 31 and the above-mentioned guide portion 32, the current collecting body 31 is provided with the exhaust passage hole 301, and the plurality of guide portions 32 are arranged on the current collecting body 31 in the circumferential direction E.

[0580] The current collecting body 31 can be welded with the tab winding portion 121 of the tab 12 to form a first welding portion 40.

[0581] The current collecting body 31 can be welded with the electrode terminal 50 to form a second welding portion 60.

[0582] Specifically, the current collecting body 31 and the guide portion 32 surround to form the second groove, so that the guide portion 32 is a relatively weak part of the current collecting member 30, and the structural strength of the guide portion 32 is lower than that of other positions of the current collecting member 30. The guide portion 32 can be provided with a notch, and the groove formed by the notch is the second groove.

[0583] By adopting the above technical solution, the guide portion 32 can guide the part of the current collecting member 30 close to the exhaust passage hole 301 to deform and turn open toward the pressure relief portion 22111 during thermal runaway, thereby facilitating to improve the directional pressure relief effect of the cylindrical battery cell 100.

[0584] In some embodiments, please refer to Figure 4 , Figure 7 and Figure 24, and in combination with other drawings. The guide portion 32 extends to the exhaust through hole 301. Understandably, the guide portion 32 and the hole wall of the exhaust through hole 301 are connected.

[0585] In other embodiments, the guide portion 32 is spaced apart from the hole wall of the exhaust through hole 301, and the minimum distance between the guide portion 32 and the hole wall of the exhaust through hole 301 is ≤10mm.

[0586] Wherein, the minimum distance between the guide portion 32 and the hole wall of the exhaust through hole 301 can be 0.1mm, 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, etc.

[0587] In this way, the guide portion 32 deforms and opens the part of the current collecting member 30 close to the exhaust through hole 301 towards the pressure relief portion 22111 when pressure relief, thereby increasing the exhaust through hole 301, to achieve efficient directional pressure relief effect.

[0588] In some embodiments, please refer to Figure 4 , Figure 7 and Figure 24 , and in combination with other drawings. The electrode assembly 10 is provided with a central hole 101 extending in the first direction Z, and the tab winding portion 121 is arranged around the outer periphery of the central hole 101. In the projection plane perpendicular to the first direction Z, the central hole 101 is located in the projection of the pressure relief portion 22111. The exhaust through hole 301 is opposite to the central hole 101 in the first direction Z and is in communication.

[0589] In this way, when the pressure value inside the shell 20 reaches the threshold value, at least part of the pressure relief portion 22111 opens to form an exhaust passage, the central hole 101, the exhaust through hole 301 and the exhaust passage are in communication in the first direction Z in turn, which facilitates exhaust and helps to improve the efficiency of directional pressure relief.

[0590] Please refer to Figure 2 , and in combination with other drawings. The battery device 1000 provided by the embodiments of the application includes a cylindrical battery cell 100. Wherein, the cylindrical battery cell 100 in the embodiments is the same as the cylindrical battery cell 100 in the above embodiments, please refer to the related description of the cylindrical battery cell 100 in the above embodiments.

[0591] The battery device 1000 provided by the embodiments of the application can achieve efficient directional pressure relief effect by adopting the cylindrical battery cell 100 related by the above embodiments, thereby helping to improve the reliability and performance of the battery device 1000.

[0592] Please refer to Figure 1, and in conjunction with other drawings. The power consumption device provided by the embodiments of the present application includes a cylindrical battery cell 100 or a battery device 1000. In the embodiments, the cylindrical battery cell 100 and the battery device 1000 are the same as those in the above embodiments, and details are described in the above embodiments, which will not be repeated here.

[0593] The power consumption device provided by the embodiments of the present application, by using the cylindrical battery cell 100 or the battery device 1000, can help improve the reliability and performance of the power consumption device.

[0594] As one of the embodiments of the present application, as shown in Figures 4 to 11As shown, the cylindrical battery cell 100 includes a housing 20 and an electrode assembly 10 disposed within the housing 20. The housing 20 is provided with a pressure relief portion 22111 at one end thereof along a first direction Z. The electrode assembly 10 is of a jelly-roll structure, and the electrode assembly 10 is provided with a central hole 101 extending along the first direction Z. The electrode assembly 10 includes a positive electrode tab 1a and a negative electrode tab 1b, each of which includes a tab body 11 and a tab lug 12 arranged along the first direction Z, and the tab lug 12 and the tab body 11 are both disposed around the outer periphery of the central hole 101. The tab lug 12 of the positive electrode tab 1a and the tab lug 12 of the negative electrode tab 1b are respectively disposed at both ends of the tab body 11 along the first direction Z. The tab body 11 is coated with an active material layer 111, and the tab lug 12 is not coated with the active material layer 111. The tab lug 12 includes a first tab lug winding portion 121a, a second tab lug winding portion 121b, and a tab lug loop portion 122, and each of the first tab lug winding portion 121a, the second tab lug winding portion 121b, and the tab lug loop portion 122 is disposed around the outer periphery of the central hole 101. The tab lug loop portion 122 is disposed around the outer periphery of the first tab lug winding portion 121a and is connected to the first tab lug winding portion 121a. The second tab lug winding portion 121b is disposed around the outer periphery of the tab lug loop portion 122 and is connected to the tab lug loop portion 122. The tab lug loop portion 122, the first tab lug winding portion 121a, and the second tab lug winding portion 121b form a first cut-off groove 102. In a projection plane perpendicular to the first direction Z, the orthographic projection of the root position of the first tab 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 tab 1 includes a first tab winding portion 14a, a second tab winding portion 14b, and a tab loop portion 15, the first tab lug winding portion 121a is formed at one end of the first tab winding portion 14a along the first direction Z, the second tab lug winding portion 121b is formed at one end of the second tab winding portion 14b along the first direction Z, and the tab lug loop portion 122 is formed at one end of the tab loop portion 15 along the first direction Z. The tab loop portion 15 is disposed around the outer periphery of the first tab winding portion 14a and is connected to the first tab winding portion 14a. The second tab winding portion 14b is disposed around the outer periphery of the tab loop portion 15 and is connected to the tab loop portion 15. The pressure relief portion 22111 is configured to at least partially open and form an exhaust passage when pressure relief occurs, and at least part of the tab 1 is discharged to the outside of the housing 20 through the exhaust passage.

[0595] The above merely describes optional embodiments of the present application and is not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of the claims of the present application.

Claims

1. A cylindrical battery cell, characterized by, The application relates to a battery, comprising: a shell, at least one end of which is provided with a pressure relief portion configured to be at least partially opened when pressure relief occurs; an electrode assembly at least partially arranged in the shell, the electrode assembly being in a winding structure and comprising two pole pieces with opposite polarities; at least one of the pole pieces comprises a pole piece main body and a tab arranged along the first direction, the pole piece main body being coated with an active material layer, and at least part of the tab being free of the active material layer; in a projection plane perpendicular to the first direction, at least part of the tab is projected within the projection of the pressure relief portion; the tab comprises a plurality of tab winding portions distributed along the winding direction of the electrode assembly, and a first cutting groove is arranged between two adjacent tab winding portions, the first cutting groove penetrates the end surface of the tab away from the pole piece main body, and 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, characterized in that, In the plurality of tab winding portions, the innermost tab winding portion is a first tab winding portion along the winding direction of the electrode assembly, and in the projection plane perpendicular to the first direction, at least part of the first tab winding portion is projected within the projection of the pressure relief portion.

3. The cylindrical battery cell of claim 2, wherein, In the projection plane perpendicular to the first direction, the projection of the first tab winding portion is within the projection of the pressure relief portion.

4. The cylindrical battery cell of claim 2, wherein, The tab comprises a plurality of the first cutting grooves, and in the projection plane perpendicular to the first direction, at least part of the first groove bottom surface of the innermost first cutting groove is projected within the projection of the pressure relief portion. Alternatively, the tab comprises one first cutting groove, and in the projection plane perpendicular to the first direction, at least part of the first groove bottom surface of the first cutting groove is projected within the projection of the pressure relief portion.

5. The cylindrical battery cell of claim 2, wherein, The pole piece comprises a first pole piece winding portion, the first tab winding portion is formed at one end of the first pole piece winding portion along the first direction, the pressure relief portion is configured to be at least partially opened and form an exhaust passage when pressure relief occurs, and at least part of the first pole piece winding portion is discharged to the outside of the shell through the exhaust passage.

6. The cylindrical battery cell of claim 5, wherein, At least one of the pole pieces has a winding starting end and a winding ending end at two ends along the winding direction of the electrode assembly, the winding starting end is formed in the first pole piece winding portion, and in the projection plane perpendicular to the first direction, the projection of the winding starting end is within the projection of the pressure relief portion.

7. The cylindrical battery cell of claim 2, wherein, The tab is provided with a central hole extending along the first direction, each tab winding portion is arranged around the outer periphery of the central hole, and in the projection plane perpendicular to the first direction, the projection of the central hole is within the projection of the pressure relief portion.

8. The cylindrical battery cell of claim 7, wherein, The outer diameter of the electrode assembly is D1, the diameter of the central hole is D2, and D2 / D1 is within the range of 5% to 25%.

9. The cylindrical battery cell according to any one of claims 1 to 8, characterized in that The number of turns of the first cutting groove along the winding direction of the electrode assembly is within the range of 2 to 4.

10. The cylindrical battery cell according to any one of claims 1 to 8, characterized in that Both of the pole pieces comprise the pole piece main body and the tab, the tabs of the two pole pieces are arranged at two ends of the electrode assembly along the first direction, and the tab of each pole piece comprises a plurality of tab winding portions.

11. The cylindrical battery cell according to any one of claims 1 to 8, characterized in that The two electrode tabs include a positive electrode tab and a negative electrode tab, and the tab ear of the positive electrode tab and / or the tab ear of the negative electrode tab is not coated with the active material layer.

12. The cylindrical battery cell according to any one of claims 1 to 8, characterized in that The electrode assembly has a winding axis parallel to the first direction, and at least one of the tab winding portions is provided with a bending section at one end in the first direction; The bending section includes a first bending portion bent in a direction close to the winding axis relative to the electrode tab body, and / or the bending section includes a second bending portion bent in a direction away from the winding axis relative to the electrode tab body.

13. The cylindrical battery cell of claim 12, wherein, Each of the tab winding portions is provided with the bending section at one end in the first direction.

14. The cylindrical battery cell according to any one of claims 1 to 8, characterized in that At least one of the electrode tabs has a winding start end and a winding end at two ends in the winding direction of the electrode assembly; Among the plurality of tab winding portions, the innermost tab winding portion is provided with a first notch groove, the first notch groove penetrates the winding start end and the end face of the tab winding portion away from the electrode tab body in the winding direction of the electrode assembly; In a projection plane perpendicular to the first direction, the orthographic projection of the third groove bottom surface of the first notch groove is located within the orthographic projection of the pressure relief portion.

15. The cylindrical battery cell of claim 14, wherein, The cylindrical battery cell further includes a current collecting member, at least part of the current collecting member is arranged in the shell; The tab winding portion has a winding start segment at one end of the first notch groove close to the electrode tab body, the third groove bottom surface is the end face of the winding start segment away from the electrode tab body, and the current collecting member is welded to the part of the tab winding portion beyond the third groove bottom surface in the direction away from the electrode tab body, and is not welded to the winding start segment.

16. The cylindrical battery cell of any one of claims 1-8, wherein, At least one of the electrode tabs has a winding start end and a winding end at two ends in the winding direction of the electrode assembly; Among the plurality of tab winding portions, the outermost tab winding portion is provided with a second notch groove, the second notch groove penetrates the winding end and the end face of the tab winding portion away from the electrode tab body in the winding direction of the electrode assembly.

17. The cylindrical battery cell of claim 16, wherein, The cylindrical battery cell further includes a current collecting member, at least part of the current collecting member is arranged in the shell; The tab winding portion has a winding end segment at one end of the second notch groove close to the electrode tab body, the fourth groove bottom surface of the second notch groove is the end face of the winding end segment away from the electrode tab body, and the current collecting member is welded to the part of the tab winding portion beyond the fourth groove bottom surface in the direction away from the electrode tab body, and is not welded to the winding end segment.

18. The cylindrical battery cell of any one of claims 1-8, wherein, At least one of the tab winding portions includes a plurality of sections distributed in the winding direction of the electrode assembly, and a second cutting groove is arranged between any two adjacent sections in the winding direction of the electrode assembly. In a projection plane perpendicular to the first direction, the orthographic projection of the second groove bottom surface of at least one of the second cutting grooves is located within the orthographic projection of the pressure relief portion.

19. The cylindrical battery cell of claim 18, wherein, The plurality of tab winding portions include adjacent first and second tab winding portions, and the second tab winding portion is arranged outside the first tab 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 of claim 18, wherein, 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; 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 of 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 of claim 18, 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 of claim 19, 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 of 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 of claim 23, wherein, The dimension of the transition connection in the first direction is H3, where 0.1mm ≤ H3 ≤ 2mm.

26. The cylindrical battery cell of claim 18, 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 of claim 18, wherein, At least one of the electrode winding portions is provided with a plurality of second cutting grooves, and in the electrode winding portion, each of the second cutting grooves and each of the cutting pieces are arranged alternately along the winding direction of the electrode assembly.

28. The cylindrical battery cell of claim 18, 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 of claim 18, 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 comprises a first bending part arranged to bend towards the direction close to the winding axis relative to the pole piece body, and / or the bending section comprises a second bending part arranged to bend away from the winding axis relative to the pole piece body.

30. The cylindrical battery cell of claim 29, wherein, Each of the segments is provided with the bending section at one end in the first direction.

31. The cylindrical battery cell of claim 12, wherein, The first bending part is arranged to bend in the radial direction of the electrode assembly; and / or the second bending part is arranged to bend in the radial direction of the electrode assembly.

32. The cylindrical battery cell of claim 12, wherein, The bending section comprises at least one first bending part and at least one second bending part, and the first bending part and the second bending part are arranged alternately in the first direction.

33. The cylindrical battery cell of any one of claims 1-8, wherein, The tab further comprises a tab loop part connected between two adjacent tab winding parts in the winding direction of the electrode assembly, and the tab loop part and the two adjacent tab winding parts in the winding direction of the electrode assembly surround to form the first cutting groove.

34. The cylindrical battery cell of claim 33, wherein, The cylindrical battery cell further comprises a current collecting member, at least part of the current collecting member is arranged in the shell, the current collecting member is welded to the tab winding part to form a first welding part, and the current collecting member is not welded to the tab loop part.

35. The cylindrical battery cell of claim 34, wherein, In the projection plane perpendicular to the first direction, the two ends of the orthogonal projection of the first welding part have a first projection end point and a second projection end point respectively, the first projection end point is closer to the winding axis parallel to the first direction than the second projection end point, and the area between the first circular arc line passing through the first projection end point and surrounding the winding axis and the second circular arc line passing through the second projection end point and surrounding the winding axis is a first cross area; At least one of the tab winding parts comprises a plurality of segments distributed in the winding direction of the electrode assembly, and between any two adjacent segments in the winding direction of the electrode assembly, a second cutting groove is arranged, at least part of the second cutting groove forms a first group of grooves, and in the first group of grooves, the orthogonal projection of the second groove bottom surface of all the second cutting grooves is located within the first cross area; The current collecting member is welded to the segment to form the first welding part; In the first group of grooves, the number of turns of a single second cutting groove is ≤3; and / or in the first group of grooves, the number of second cutting grooves opposite and connected in the radial direction of the electrode assembly is ≤3.

36. The cylindrical battery cell of claim 34, wherein, The cylindrical battery cell further comprises an electrode terminal fixed to the shell, and the electrode terminal is welded to the current collecting member to form a second welding part.

37. The cylindrical battery cell of claim 36, wherein, In the projection plane perpendicular to the first direction, the two ends of the orthogonal projection of the second welding part have a third projection end point and a fourth projection end point respectively, the third projection end point is closer to the winding axis parallel to the first direction than the fourth projection end point, and the area between the third circular arc line passing through the third projection end point and surrounding the winding axis and the fourth circular arc line passing through the fourth projection end point and surrounding the winding axis is a second cross area; At least one of the tab winding portions includes a plurality of segments distributed along the winding direction of the electrode assembly, and in the tab winding portion, a second cut groove is arranged between any two adjacent segments along the winding direction of the electrode assembly, and at least part of the second cut groove forms a second group of grooves, in which the orthographic projection of the second groove bottom surface of all the second cut grooves is located within the second transverse area; In the second group of grooves, the number of turns of a single second cut groove is ≤3; and / or in the second group of grooves, the number of second cut grooves that are opposite and connected along the radial direction of the electrode assembly is ≤3.

38. The cylindrical battery cell of claim 36, wherein, At least one of the tabs has a winding start end and a winding end at both ends along the winding direction of the electrode assembly; In the plurality of tab winding portions, the innermost tab winding portion along the winding direction of the electrode assembly 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 surface of the tab away from the tab body; In the projection plane perpendicular to the first direction, the orthographic projection of the third groove bottom surface of the first notch groove is located within the orthographic projection of the pressure relief portion; In the radial direction of the electrode assembly, the first welding portion is located outside the first notch groove; and / or in the radial direction of the electrode assembly, the second welding portion is located outside the first notch groove.

39. The cylindrical battery cell of claim 36, wherein, At least one of the tabs has a winding start end and a winding end at both ends along the winding direction of the electrode assembly; In the plurality of tab winding portions, the outermost tab winding portion along the winding direction of the electrode assembly is provided with a second notch groove, the second notch groove penetrates the winding end along the winding direction of the electrode assembly, and penetrates the end surface of the tab away from the tab body; In the radial direction of the electrode assembly, the second notch groove is located outside the first welding portion; and / or in the radial direction of the electrode assembly, the second notch groove is located outside the second welding portion.

40. The cylindrical battery cell of claim 34, wherein, Both of the tabs include the tab body and the tab, the tab of one of the tabs is a first tab, the tab of the other of the tabs is a second tab, the first tab and the second tab are respectively arranged at both ends of the electrode assembly along the first direction, and both of the first tab and the second tab include a plurality of tab winding portions; In the first direction, both ends of the electrode assembly are provided with the current collecting members, and the current collecting members located at both ends of the electrode assembly are respectively a first current collecting member and a second current collecting member; The shell includes a second end wall, a first end wall, and a side wall, the second end wall and the first end wall are respectively arranged at both ends of the side wall along the first direction, and the second end wall is provided with an electrode terminal; The first current collecting member is welded to the tab winding portion of the first tab and electrically connected with the electrode terminal; and the second current collecting member is welded to the tab winding portion of the second tab and electrically connected with the side wall.

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

42. The cylindrical battery cell of claim 40, wherein, In the radial direction of the electrode assembly, the side wall is inwardly convexly formed with a protrusion, the protrusion and the electrode assembly are distributed along the first direction, and the second current collecting member is welded to one side of the protrusion close to or away from the electrode assembly.

43. The cylindrical battery cell of claim 40, wherein, The first tab is a positive electrode tab, and the second tab is a negative electrode tab.

44. The cylindrical battery cell of claim 40, wherein, The first end wall is provided with the pressure relief portion.

45. The cylindrical battery cell of claim 34, wherein, The current collecting member is provided with an exhaust through hole extending along the first direction, the exhaust through hole is oppositely arranged with the pressure relief portion along the first direction; the current collecting member is provided with a plurality of guide portions, and the plurality of guide portions are arranged at intervals around the outer periphery of the exhaust through hole.

46. The cylindrical battery cell of claim 45, wherein, The guide portion extends to the exhaust through hole; or, the guide portion is arranged at an interval with 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 of claim 45, wherein, In the projection plane perpendicular to the first direction, along the radial direction of the electrode assembly, the orthographic projection of one end of the guide portion away from the exhaust through hole 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 of claim 45, wherein, The guide portion includes a through hole penetrating the current collecting member along the first direction; and / or, the guide portion includes a second groove not penetrating the current collecting member along the first direction.

49. The cylindrical battery cell of claim 45, wherein, The electrode assembly is provided with a center hole extending along the first direction, the tab winding portion is arranged around the outer periphery of the center hole, the exhaust through hole is oppositely arranged with the center hole along the first direction and is in communication with the center hole; In the projection plane perpendicular to the first direction, the orthographic projection of the center hole is located within the orthographic projection of the pressure relief portion.

50. The cylindrical battery cell of any one of claims 1-8, wherein, The shell further comprises a first end wall opposite to the electrode assembly along the first direction, the first end wall is provided with a first groove and the pressure relief portion located in the area surrounded by the first groove, the bottom of the first groove is provided with a weak portion, the pressure relief portion is connected to the weak portion, and at least part of the weak portion is configured to be broken to open the pressure relief portion when pressure relief.

51. The cylindrical battery cell of any one of claims 1-8, wherein, The shell further comprises a first wall and a pressure relief mechanism, the first wall is arranged opposite to the electrode assembly along the first direction; the first wall is fixedly connected to the pressure relief mechanism, the pressure relief mechanism is provided with a first groove and the pressure relief portion located in the area surrounded by the first groove, the bottom of the first groove is provided with a weak portion, the pressure relief portion is connected to the weak portion, and at least part of the weak portion is configured to be broken to open the pressure relief portion when pressure relief.

52. The cylindrical battery cell of any one of claims 1-8, wherein, In the projection plane perpendicular to the first direction, the outer contour of the orthographic projection of the pressure relief portion is circular.

53. A battery device, comprising: The cylindrical battery cell according to any one of claims 1-52.

54. An electrical device, comprising: The cylindrical battery cell according to any one of claims 1-52; or, the battery device according to claim 53.

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