Battery cell, battery device, and electric device

Abstract

The application provides a battery monomer, a battery device and a power utilization device, and belongs to the technical field of batteries. The battery monomer comprises a shell, a first electrode terminal, a first current collecting member and an electrode assembly. A main body part of the electrode assembly comprises a plurality of first pole segments stacked along a second direction, and a first tab of the electrode assembly comprises a plurality of sub-tabs, each of which is connected to one end of a first pole segment close to a first wall and is bent towards the second direction. The first current collecting member is at least partially arranged between the main body part and the first wall and is connected to the first electrode terminal. The connection areas of the plurality of sub-tabs are stacked on a side of the first current collecting member away from the main body part and are welded with the first current collecting member to form a first welding part. Adjacent two connection areas are fixedly connected only through the first welding part, and the connection area farthest from the main body part is larger than the connection area closest to the main body part in the second direction, so as to reduce the damage of the sub-tab and improve the overcurrent reliability of the first tab and the first current collecting member.

Description

Technical Field

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

[0002] In recent years, new energy vehicles have experienced rapid development. In the field of electric vehicles, power batteries, as the power source, play an irreplaceable and crucial role. With the vigorous promotion of new energy vehicles, the demand for power battery products is also increasing day by day.

[0003] In battery technology, a battery device includes a housing and multiple battery cells housed within the housing. Each battery cell includes a casing and electrode assemblies and current collectors housed within the casing. Correspondingly, the casing is also provided with electrode terminals that are electrically connected to the tabs of the electrode assemblies. The electrode terminals are connected to the tabs through the current collectors to realize the input or output of electrical energy of the battery cell. However, existing battery cells are prone to connection failures and other risks during use, which is not conducive to improving the stability and reliability of the battery cells. Utility Model Content

[0004] This application provides a battery cell, a battery device, and an electrical device, which can effectively improve the energy density of the battery cell.

[0005] In a first aspect, embodiments of this application provide a battery cell, including a casing, a first electrode terminal, a first current collector, and at least one electrode assembly; the casing has a first wall, the thickness direction of the first wall being parallel to a first direction; the first electrode terminal is disposed in the casing; the electrode assembly is housed within the casing, the electrode assembly including a main body and a first tab, the main body including a plurality of first electrode segments stacked along a second direction and having the same polarity, the first tab including a plurality of sub-tabs stacked, each of the sub-tabs of each first tab being connected to one end of a first electrode segment near the first wall, and the sub-tabs being bent toward the second direction, the second direction being perpendicular to the first direction; at least a portion of the first current collector is disposed in the main body and the first electrode terminal. Between the walls, and the first current collector is connected to the first electrode terminal; along the first direction, the sub-tab has a connection area located on the side of the first current collector away from the main body, the connection areas of the plurality of sub-tabs of each first electrode are stacked and welded to the first current collector to form at least one first solder mark, the first electrode has a first surface away from the main body, at least a portion of each first solder mark extends from the first surface through at least a portion of the connection area and into the first current collector, two adjacent connection areas are fixedly connected only by the first solder mark, and among the plurality of connection areas, the dimension of the connection area furthest from the main body in the second direction is greater than the dimension of the connection area closest to the main body in the second direction.

[0006] In the above technical solution, multiple sub-tabs of the first electrode tab are bent toward the second direction. The connection areas of the multiple sub-tabs are stacked along the first direction on the side of the first current collector component away from the main body and welded to the first current collector component to form a first solder mark. At least part of the first solder mark is a structure that extends from the first surface of the first electrode tab into the first current collector component. This makes the connection area of ​​the first electrode tab located on the side of the first current collector component away from the main body and welded to the first electrode tab and the first current collector component in the first direction, so as to realize the assembly connection between the first electrode tab and the first current collector component. Two adjacent sub-tabs are fixedly connected only through the first solder mark. The battery cell with this structure can realize that after the first electrode tab is bent toward the second direction and before the connection area of ​​the first electrode tab is stacked and welded to the first current collector component, the multiple sub-tabs of the first electrode tab are not fixedly connected or pre-welded, so as to facilitate the first electrode tab to be assembled first. After the multiple sub-tabs of the first electrode are smoothed and bent, the first electrode and the first current collector are welded together. This allows the multiple sub-tabs to move and shift relative to each other during the smoothing and bending process, enabling each sub-tab to adapt to the length changes caused by bending. This reduces local stress concentration or bulging of the sub-tabs during the smoothing and bending process, effectively improving the welding quality between the first electrode and the first current collector. It also effectively mitigates cracking or breakage of the sub-tabs during assembly or use, reducing the risk of unstable connection and connection failure between the first electrode and the first current collector during use. This is beneficial to improving the stability and reliability of the battery cell. On the other hand, it reduces the welding difficulty between the smoothed and bent first electrode and the first current collector, and facilitates the smoothing and bending of the multiple sub-tabs of the first electrode based on the first current collector, thus reducing the bending difficulty of the sub-tabs. Furthermore, since the sub-tab closest to the first surface in the first electrode tab is easily damaged during welding, the size of the connection area furthest from the main body in the second direction among the multiple stacked connection areas is set to be larger than the size of the connection area closest to the main body in the second direction. This makes the area of ​​the connection area furthest from the main body relatively larger, thereby increasing the weldable area between the sub-tab closest to the first surface in the first electrode tab and the first current collector. This helps to mitigate the phenomenon of reduced effective connection area or connection failure between the sub-tab closest to the first surface in the first electrode tab and the first current collector due to damage during welding, and is beneficial to improving the overcurrent reliability between the sub-tab closest to the first surface in the first electrode tab and the first current collector.

[0007] In some embodiments, the connection region furthest from the main body among the plurality of connection regions has the largest size in the second direction.

[0008] In the above technical solution, by setting the connection area furthest from the main body among multiple connection areas as the structure with the largest size in the second direction, the connection area furthest from the main body can be welded to the first current collector with the largest area. This further alleviates the phenomenon that the sub-tab closest to the first surface in the first electrode tab is damaged during the welding process, resulting in a reduction in the effective connection area or connection failure between it and the first current collector. This is beneficial to further improve the overcurrent reliability between the sub-tab closest to the first surface in the first electrode tab and the first current collector.

[0009] In some embodiments, in at least two partially adjacent connection regions, the dimension of the connection region farther from the main body in the second direction is greater than the dimension of the connection region closer to the main body in the second direction.

[0010] In the above technical solution, by setting the size of the connection area farther from the main body in the second direction of at least two partially adjacent connection areas to be larger than the size of the connection area closer to the main body in the second direction, the size of the multiple stacked connection areas in the second direction gradually decreases from the connection area farthest from the main body to the connection area closest to the main body. The battery cell with this structure can improve the regularity of the multiple sub-tabs after they are smoothed, bent and stacked on the side of the first current collector away from the main body, and facilitate the welding connection of multiple connection areas to the first current collector. On the other hand, it is easy to realize that the connection area of ​​each sub-tab can be welded to the first current collector, so as to reduce the phenomenon that the connection area of ​​some sub-tabs is not welded to the first current collector.

[0011] In some embodiments, the plurality of sub-tabs includes a first sub-tab, the connection region of the first sub-tab being the connection region closest to the main body among the plurality of connection regions; the dimension of the connection region of the first sub-tab in the second direction is greater than or equal to 5 mm.

[0012] In the above technical solution, by setting the smallest connecting area in the second direction among multiple connecting areas to a size greater than or equal to 5mm in the second direction, the structure of all connecting areas having a size of at least greater than or equal to 5mm in the second direction can be improved, thereby increasing the connectable area between the connecting area and the first solder mark in the second direction, which is beneficial to further improve the connection stability and flow area between the sub-electrode and the first current collector.

[0013] In some embodiments, the plurality of sub-tabs include a first sub-tab, the connection region of the first sub-tab being the connection region closest to the main body among the plurality of connection regions; at least one of the first solder marks extends beyond the first sub-tab at an end away from the first electrode segment in the second direction.

[0014] In the above technical solution, by setting at least one first solder mark in the second direction to extend beyond the end of the first sub-tab that is far from the first pole segment, the size of the first solder mark in the second direction is not limited by the connection area with the shortest size in the second direction, thereby increasing the connection area between the first pole and the first solder mark, and thus further improving the connection stability and flow area between the first pole and the first current collector.

[0015] In some embodiments, the area through which the sub-tab is traversed by the first solder mark forms a solder mark area; in at least two partially adjacent connection areas, the solder mark area on the connection area farther from the main body has a larger size in the second direction than the solder mark area on the connection area closer to the main body has a larger size in the second direction.

[0016] In the above technical solution, by setting the size of the solder area in the second direction on the connection area farther from the main body in at least two partially adjacent connection areas to be larger than the size of the solder area in the second direction on the connection area closer to the main body, the size of the solder area in the second direction on the multiple stacked connection areas gradually decreases from the connection area farthest from the main body to the connection area closest to the main body. This is because, for the sub-tabs farther from the first current collector, the current path between them is longer and the internal resistance is greater, resulting in relatively poor current stability. Therefore, a battery cell with this structure can achieve a situation where the sub-tabs farther from the first current collector have a longer current path and greater internal resistance, leading to relatively poor current stability. The larger the welding area between them, the better to balance the internal resistance between each sub-tab and the first current collector, thus balancing the current flow effect between each sub-tab and the first current collector. On the other hand, since the sub-tabs closer to the first surface are more susceptible to welding damage during the welding process, this battery cell structure can achieve a larger welding area between the sub-tabs closer to the first surface and the first current collector. This alleviates the problem of sub-tabs closer to the first surface being easily damaged during the welding process, resulting in a reduction in the effective connection area or connection failure between them and the first current collector, thereby improving the connection stability and current flow effect between the first tab and the first current collector.

[0017] In some embodiments, the plurality of sub-tabs include a second sub-tab, and the connection area of ​​the second sub-tab is the connection area furthest from the main body among the plurality of connection areas; in a projection plane perpendicular to the first direction, the orthographic projections of all the first solder marks in the same first tab are located within the orthographic projection of the second sub-tab.

[0018] In the above technical solution, by setting the orthographic projection of all the first solder marks in the same first electrode ear in the projection plane perpendicular to the first direction to be located in the orthographic projection of the second sub-electrode ear in the projection plane perpendicular to the first direction, each first solder mark in the same first electrode ear is a structure that first passes through the second sub-electrode ear and then connects with other sub-electrode ears and the first current collector, thereby maximizing the welding area of ​​the second sub-electrode ear. This further alleviates the phenomenon that the second sub-electrode ear closest to the first surface in the first electrode ear is damaged during the welding process, resulting in a reduction in the effective connection area or connection failure between it and the first current collector, which is beneficial to further improve the overcurrent reliability between the second sub-electrode ear closest to the first surface in the first electrode ear and the first current collector.

[0019] In some embodiments, along the first direction, at least one of the first solder marks passes through the connection area of ​​all the sub-tabs in the first tab.

[0020] In the above technical solution, by setting at least one first solder mark as the connection area passing through all the sub-tabs in the corresponding first electrode tab, all the connection areas of the sub-tabs in the first electrode tab are fixedly connected to at least the first solder mark, and each sub-tab in the first electrode tab is welded to the first current collector, thereby further improving the current flow effect and connection stability between the first electrode tab and the first current collector, and reducing the risk of excessively long current flow paths or connection failures in the first electrode segment caused by the sub-tabs on some first electrode segments not being welded to the first current collector.

[0021] In some embodiments, along the first direction, the thickness of the portion of the first solder mark extending into the first current collector is T1, and the thickness of the region of the first current collector connected to the first solder mark is T2, satisfying 0.25≤T1 / T2≤0.75.

[0022] In the above technical solution, on the one hand, the thickness of the portion of the first solder mark extending into the first current collector is set to be greater than or equal to 0.25 times the thickness of the area where the first current collector is connected to the first solder mark, so as to improve the welding penetration of the first solder mark in the first current collector, thereby improving the current flow effect between the first tab and the first current collector, and also improving the connection stability between the first tab and the first current collector. On the other hand, the thickness of the portion of the first solder mark extending into the first current collector is set to be less than or equal to 0.75 times the thickness of the area where the first current collector is connected to the first solder mark, so as to reduce the risk of the first current collector being burned through and damaging other components.

[0023] In some embodiments, along the first direction, the thickness of the area where the first current collector is connected to the first solder mark is 0.3 mm to 4 mm.

[0024] In the above technical solution, on the one hand, the thickness of the area where the first current collector is connected to the first solder mark is set to be greater than or equal to 0.3 mm, so as to reduce the risk of the first current collector being burned or damaged after being soldered through, and to increase the depth of the molten pool of the first solder mark in the first current collector, thereby improving the welding reliability between the first electrode and the first current collector, and also improving the structural strength of the first current collector. On the other hand, the thickness of the area where the first current collector is connected to the first solder mark is set to be less than or equal to 4 mm, so as to alleviate the phenomenon that the first current collector occupies too much space between the first electrode and the main body, which is conducive to optimizing the space occupied by the first electrode and the first current collector as a whole in the first direction, and also conducive to reducing the difficulty of bending multiple sub-electrodes toward the second direction and extending to the side of the first current collector away from the main body.

[0025] In some embodiments, the extension dimension of the sub-electrode from one end connected to the first electrode segment to the end away from the first electrode segment is 5mm-40mm.

[0026] In the above technical solution, on the one hand, the extension dimension of the sub-electrode from one end connected to the first electrode segment to the end away from the first electrode segment is set to be greater than or equal to 5mm. This reduces the difficulty of bending multiple sub-electrodes in the second direction and extending them to the side of the first current collector component away from the main body. It also reduces the difficulty of stacking and welding the multiple connection areas formed by the multiple sub-electrodes after bending with the first current collector component. Furthermore, it helps to increase the area of ​​the connection areas formed by the sub-electrodes after bending, thereby increasing the area where the sub-electrodes can be stacked and welded with the first current collector component. On the other hand, because the first electrode... The multiple sub-tabs of the first electrode are not fixed to each other before being welded and assembled with the first current collector. This allows the multiple sub-tabs to move and shift relative to each other during the process of smoothing and bending the first electrode. By setting the extension dimension of the sub-tab from one end connected to the first electrode segment to the end away from the first electrode segment to less than or equal to 40mm, the phenomenon of redundancy or local bulging of the sub-tab after bending can be effectively alleviated. This is to optimize the space occupied by the first electrode in the first direction, which is conducive to improving the internal space utilization of the battery cell and thus improving the energy density of the battery cell.

[0027] In some embodiments, in a projection plane perpendicular to the first direction, the orthographic projection of the first solder mark is a strip structure extending along a straight trajectory, and the length direction of the orthographic projection of the first solder mark is parallel to the second direction or the angle between the length direction of the orthographic projection of the first solder mark and the second direction is less than or equal to 30°.

[0028] In the above technical solution, since the multiple first electrode segments are stacked along the second direction and the sub-electrode tabs are bent towards the second direction, the connection positions of the multiple sub-electrode tabs of the first electrode tab and the corresponding first electrode segments are arranged along the second direction. Before the bending, the multiple sub-electrode tabs of the first electrode tab are arranged along the second direction. After the multiple sub-electrode tabs are bent towards the second direction, by setting the orthographic projection of the first solder part in the projection plane perpendicular to the first direction as a strip structure extending along a straight trajectory, and the length direction of the orthographic projection of the first solder part in the projection plane perpendicular to the first direction is parallel to the second direction or the angle between the first solder part and the second direction is less than or equal to 30°, it is possible to further realize the interconnection of the first solder part with more sub-electrode tabs, thereby further improving the current flow effect between the first electrode tab and the first current collector, and further improving the connection stability between the first electrode tab and the first current collector.

[0029] In some embodiments, there are multiple first solder marks on the first tab, and the multiple first solder marks are arranged at intervals along a third direction, with the first direction, the second direction and the third direction being perpendicular to each other.

[0030] In the above technical solution, by setting multiple first solder marks on the first tab, and the multiple first solder marks being arranged at intervals along a third direction, the orthographic projection of the multiple first solder marks in the projection plane perpendicular to the first direction is a structure arranged at intervals along its width direction. The battery cell with this structure can, on the one hand, further improve the welding reliability and welding area between the first tab and the first current collector, thereby further improving the current flow effect between the first tab and the first current collector, and further improving the connection stability between the first tab and the first current collector. On the other hand, even if there is a connection failure between the sub-tab and some of the first solder marks, the multiple first solder marks can ensure that the sub-tab can still maintain connection with the first current collector through the remaining first solder marks, thereby improving the fault tolerance rate of the welding assembly between the sub-tab and the first current collector, and improving the electrical connection stability between the sub-tab and the first current collector, so as to reduce the risk of connection failure between the sub-tab and the first current collector.

[0031] In some embodiments, along the third direction, the minimum distance between two adjacent first solder pads is 1mm-10mm.

[0032] In the above technical solution, on the one hand, the minimum spacing between two adjacent first solder marks in the third direction is set to be greater than or equal to 1mm, which can reduce the forming difficulty of multiple first solder marks arranged at intervals along the third direction, thereby reducing the welding difficulty between the first electrode and the first current collector, and can reduce the influence of the molten pool between two adjacent first solder marks, which is conducive to improving the connection quality between each first solder mark and the first electrode. On the other hand, the minimum spacing between two adjacent first solder marks in the third direction is set to be less than or equal to 10mm, so as to alleviate the phenomenon that the number of first solder marks set on the first electrode is limited due to the excessive spacing between two adjacent first solder marks, thereby facilitating the welding of more first solder marks between the first electrode and the first current collector, which is conducive to improving the connection stability and current flow effect between the first electrode and the first current collector.

[0033] In some embodiments, each of the sub-tabs is fixedly connected to at least two of the first solder pads.

[0034] In the above technical solution, by fixing each sub-tab to at least two first solder marks, each sub-tab is a structure through which at least two first solder marks pass. On the one hand, this can increase the current-passing area and current-passing path between each sub-tab and the first current collector. On the other hand, it can still be electrically connected to the first current collector through other first solder marks even if the sub-tab fails to connect with one or some of the first solder marks, which is beneficial to improving the electrical connection stability between the sub-tab and the first current collector.

[0035] In some embodiments, in a projection plane perpendicular to the first direction, the width of the orthographic projection of the first solder mark in a third direction is 0.5mm-5mm, and the first direction, the second direction, and the third direction are perpendicular to each other.

[0036] In the above technical solution, on the one hand, the width of the orthographic projection of the first solder mark in the projection plane perpendicular to the first direction in the third direction is set to be greater than or equal to 0.5 mm, so as to increase the connection area between the first solder mark and the sub-electrode, thereby improving the current flow effect between the first electrode and the first current collector, and also improving the connection stability between the first electrode and the first current collector. On the other hand, the width of the orthographic projection of the first solder mark in the projection plane perpendicular to the first direction in the third direction is set to be less than or equal to 5 mm, so as to alleviate the phenomenon that the weld pool width of the first solder mark formed by the welding of the first current collector and the first electrode is too large, which is conducive to reducing the power required for welding and assembling the first current collector and the first electrode, and can reduce the area of ​​the sub-electrode passed through by the first solder mark, thereby reducing the risk of damage to the sub-electrode.

[0037] In some embodiments, the area through which the sub-electrode is passed by the first solder mark forms a solder mark area, the surface area of ​​the sub-electrode on one side in its thickness direction is S1, and the sum of the areas of all the solder marks on the same sub-electrode is S2, satisfying 0.0075≤S2 / S1≤0.1.

[0038] In the above technical solution, on the one hand, the sum of the areas of all solder areas is set to be greater than or equal to 0.0075 times the surface area of ​​the corresponding sub-electrode on one side in the thickness direction, so as to increase the welding area between the single sub-electrode and the first current collector, thereby improving the current flow effect between the single sub-electrode and the first current collector, and also improving the connection stability between the single sub-electrode and the first current collector. On the other hand, the sum of the areas of all solder areas is set to be less than or equal to 0.1 times the surface area of ​​the corresponding sub-electrode on one side in the thickness direction, so as to alleviate the phenomenon that the area through which the sub-electrode is passed by the first solder part is too large, thereby reducing the welding difficulty between the single sub-electrode and the first current collector, and also reducing the power required for welding and assembling the first current collector and the first electrode.

[0039] In some embodiments, the sub-taper has a connection end connected to the first pole segment, and in a projection plane perpendicular to the first direction, at least a portion of the orthographic projection of the connection end of the sub-taper lies within the orthographic projection of the first current collector, and the sub-taper whose orthographic projection of the connection end lies within the orthographic projection of the first current collector bends around the first current collector.

[0040] In the above technical solution, by setting the orthographic projection of at least some of the sub-tabs in a projection plane perpendicular to the first direction as a structure located within the orthographic projection of the first current collector in a projection plane perpendicular to the first direction, at least some of the sub-tabs are located between the first current collector and the main body. This makes the sub-tabs extend from the side of the first current collector facing the main body, bends around the first current collector, and extends to the side of the first current collector away from the main body. With this structure, the battery cell can, on the one hand, achieve the function of separating at least some of the sub-tabs between the first current collector and the main body, thereby reducing the risk of the main body being burned or damaged after the first current collector is soldered through. On the other hand, it can achieve the sharing of a portion of space between the first current collector and the first tab in the first direction, and also achieve the sharing of a portion of space between the first current collector and the first tab in the second direction. This is beneficial to optimize the overall space occupied by the first current collector and the first tab, thereby improving the internal space utilization of the battery cell and thus improving the energy density of the battery cell.

[0041] In some embodiments, along the first direction, the portion of the sub-electrode located between the first current collector and the main body gradually moves away from the main body from one end connected to the first pole segment to the end away from the first pole segment.

[0042] In the above technical solution, since the multiple sub-tabs of the first electrode are not fixedly connected or pre-welded after the first electrode is bent toward the second direction and before the first electrode is stacked and welded with the first current collector, the multiple sub-tabs of the first electrode are a structure that can be smoothed and bent before being welded and assembled with the first current collector. Thus, the part of the sub-tab located between the first current collector and the main body is set to gradually move away from the main body from one end connected to the first electrode segment to the end away from the first electrode segment. This reduces the phenomenon of local bulging or swelling of the part of the sub-tab located between the first current collector and the main body due to stress. In this way, the risk of cracking or breaking of the part of the sub-tab located between the first current collector and the main body during assembly or use can be reduced, and the space occupied by the part of the multiple sub-tabs located between the first current collector and the main body in the first direction can be saved to improve the energy density of the battery cell.

[0043] In some embodiments, the sub-taper has a connection end connected to the first pole segment, and in a projection plane perpendicular to the first direction, the orthographic projection of the first current collector does not overlap with the orthographic projection of the connection end of all the sub-tapers.

[0044] In the above technical solution, by setting the orthographic projection of all the connecting ends of the sub-tabs in the projection plane perpendicular to the first direction to a structure that does not overlap with the orthographic projection of the first current collector in the projection plane perpendicular to the first direction, the first current collector is located between the sub-tabs and the main body, and the sub-tabs are designed to start from one side of the first current collector in the second direction, bend around the first current collector, and extend to the side of the first current collector away from the main body. The battery cell with this structure can reduce the difficulty of smoothing and bending the sub-tabs, and reduce the difficulty of stacking and welding multiple sub-tabs of the first tab with the first current collector. On the other hand, it can realize that the first current collector and the first tab share part of the space in the first direction, and can further optimize the size of the first current collector and the main body in the first direction, thereby saving the space occupied by the first tab and the first current collector as a whole in the first direction, improving the internal space utilization of the battery cell, and thus improving the energy density of the battery cell.

[0045] In some embodiments, the battery cell further includes a heat insulation component; at least a portion of the heat insulation component is disposed between the first current collector and the main body in the first direction, and at least a portion of the orthographic projection of the first solder mark is located within the orthographic projection of the heat insulation component in a projection plane perpendicular to the first direction.

[0046] In the above technical solution, by setting at least a portion of the heat insulation component in the first direction as a structure located between the first current collector and the main body, and setting at least a portion of the orthogonal projection of the first solder mark in a projection plane perpendicular to the first direction as a structure located within the orthogonal projection of the heat insulation component in a projection plane perpendicular to the first direction, the first solder mark is located on the side of the heat insulation component away from the main body in the first direction, thereby enabling the heat insulation component to play a heat insulation role between the first solder mark and the main body, thereby reducing the phenomenon of the first current collector and the first electrode being burned by the main body and other components during the welding connection and formation of the first solder mark, so as to improve the assembly quality of the battery cell.

[0047] In some embodiments, in a projection plane perpendicular to the first direction, the orthographic projection of the first solder mark is entirely located within the orthographic projection of the heat insulation component.

[0048] In the above technical solution, by setting the entire orthographic projection of the first solder mark in the projection plane perpendicular to the first direction as a structure located within the orthographic projection of the heat insulation component in the projection plane perpendicular to the first direction, the heat insulation effect of the heat insulation component between the first solder mark and the main body can be further improved. This can further reduce the phenomenon of the first current collector and the first electrode being burned by the main body and other components during the welding connection and formation of the first solder mark, thereby further improving the assembly quality of the battery cell.

[0049] In some embodiments, the heat insulation element is made of an insulating material.

[0050] In the above technical solution, by setting the material of the heat insulation component to an insulating material, the heat insulation component can also play an insulating isolation role between the first current collector and the main body, thereby reducing the risk of short circuit between the first current collector and the main body during use and improving the reliability of the battery cell.

[0051] In some embodiments, the heat insulation element is attached to the surface of the first manifold facing the main body.

[0052] In the above technical solution, by setting the heat insulation component as a structure connected to the surface of the first current collector facing the main body, on the one hand, the heat insulation component can be assembled together with the first current collector between the first electrode and the main body, which helps to reduce the difficulty of setting the heat insulation component between the first current collector and the main body and optimize the production cycle. On the other hand, it can improve the stability and reliability of the heat insulation component set between the first current collector and the main body, which helps to reduce the risk of the heat insulation component falling off between the first current collector and the main body during the welding process between the first current collector and the first electrode.

[0053] In some embodiments, the battery cell further includes a support member; the support member is supported between the first current collector and the main body portion along the first direction, and at least a portion of the orthographic projection of the first solder mark portion is located within the orthographic projection of the support member in a projection plane perpendicular to the first direction.

[0054] In the above technical solution, by providing a support member between the first current collector and the main body, and at least a portion of the orthographic projection of the first solder mark in a projection plane perpendicular to the first direction is located within the orthographic projection of the support member in a projection plane perpendicular to the first direction, the support member can provide support and stability for the area of ​​the first current collector used for welding with the first tab, thereby reducing the welding gap between the first tab and the first current collector, and reducing the shaking phenomenon of the first current collector during welding assembly, thereby reducing the risk of incomplete welding between the first tab and the first current collector, and improving the welding quality of the first tab and the first current collector.

[0055] In some embodiments, the first electrode terminal is disposed on the first wall, the first current collector is disposed between the main body and the first wall in the first direction, and the first current collector and the first electrode terminal are welded together to form a second solder mark.

[0056] In the above technical solution, by setting the first electrode terminal on the first wall, the first tab, the first current collector and the first electrode terminal are all located on the side of the main body facing the first wall in the first direction, which helps to reduce the welding and assembly difficulty between the first current collector and the first tab and between the first current collector and the first electrode terminal.

[0057] In some embodiments, along the first direction, the outer surface of the first electrode terminal opposite to the body portion includes a second surface, and at least a portion of the second solder mark extends from the second surface into the first current collector.

[0058] In the above technical solution, by setting at least a portion of the second solder mark formed by welding the first current collector and the first electrode terminal together as a structure extending from the second surface of the first electrode terminal away from the main body into the first current collector, the welding assembly between the first current collector and the first electrode terminal is a structure in which the first current collector and the first electrode terminal are welded from the side of the first electrode terminal away from the main body in the first direction. Thus, on the one hand, since the gap between the first current collector and the main body is too small after the first electrode tab is flattened, bent and welded to the first current collector, this assembly structure can reduce the welding difficulty between the first current collector and the first electrode terminal. On the other hand, it can reduce the phenomenon of welding slag and other particles generated by welding the first current collector and the first electrode terminal falling into the casing, thereby reducing the risk of internal short circuits in the battery cell during use.

[0059] In some embodiments, the first electrode terminal includes a first connecting portion located within the housing, the first connecting portion having a first side surface and a third surface facing the main body in the first direction, the first side surface surrounding and connected to the third surface; the first current collector includes an interconnected tab connecting portion and a terminal connecting portion, wherein, along the first direction, the connecting areas of a plurality of sub-tabs of each first tab are stacked on the side of the tab connecting portion away from the main body and welded to the tab connecting portion to form the first solder mark portion, and the terminal connecting portion extends in a direction away from the main body and is welded to the first side surface to form the second solder mark portion.

[0060] In the above technical solution, the electrode connection part and the first electrode part are stacked and welded together along the first direction, and the terminal connection part is a structure that extends away from the main body in the first direction and is welded to the first side. This makes the electrode connection part and the terminal connection part interconnected to form an L-shaped or T-shaped structure and welded to the first connection part of the first electrode and the first electrode terminal respectively. This achieves electrical connection between the first electrode and the first electrode terminal, and also allows the terminal connection part and the first connection part to share a space in the first direction. In addition, since the gap between the first current collector and the main body is too small after the first electrode is flattened, bent and welded to the electrode connection part, the battery cell with this structure can also achieve welding assembly of the terminal connection part and the first side from one side of the first current collector, thereby effectively reducing the welding difficulty between the first current collector and the first electrode terminal. It also allows the second solder mark to be built into the shell, reducing the risk of rusting of the second solder mark during use and the risk of leakage of the battery cell at the location of the second solder mark.

[0061] In some embodiments, the first current collector is located between the main body and the first electrode terminal, and the first current collector includes a tab connection portion, a bending portion and a terminal connection portion connected in sequence; along the first direction, the connection areas of a plurality of sub-tabs of each first tab are stacked on the side of the tab connection portion away from the main body and welded to the tab connection portion to form the first solder mark portion, and the terminal connection portion is located on the side of the tab connection portion facing the first electrode terminal and welded to the first electrode terminal to form the second solder mark portion.

[0062] In the above technical solution, the first current collector includes a terminal connection portion, a bending portion, and an electrode tab connection portion connected in sequence. The terminal connection portion is located on the side of the electrode tab connection portion facing the first electrode terminal and is welded to the first electrode terminal. The electrode tab connection portion and the portion of the first electrode tab are stacked and welded together along a first direction, so that the terminal connection portion, the bending portion, and the electrode tab connection portion are connected in sequence to form a U-shaped structure. Furthermore, the terminal connection portion and the electrode tab connection portion are arranged along the first direction and welded to the first electrode terminal and the first electrode tab respectively, thereby achieving an electrical connection between the first electrode tab and the first electrode terminal. In addition, because the first electrode tab, after being smoothed, bent, and welded to the electrode tab connection portion... The gap between the first current collector and the main body is too small. Therefore, the battery cell with this structure can first weld the unfolded first current collector to the first tab and the first electrode terminal, and then bend the first current collector to form a bent part. After that, the electrode assembly and other components are assembled into the housing. This is conducive to welding and assembling the terminal connection part and the first electrode terminal from one side of the first current collector, thereby effectively reducing the welding difficulty between the first current collector and the first electrode terminal. It also allows the second solder mark to be built into the housing, thereby reducing the risk of rusting of the second solder mark during use and the risk of leakage of the battery cell at the location of the second solder mark.

[0063] In some embodiments, the electrode assembly includes a plurality of first tabs with the same polarity. The plurality of first tabs are all connected to one end of the main body facing the first wall and are spaced apart along a third direction. The plurality of first tabs are all welded to the first current collector to form the first solder mark. The first direction, the second direction and the third direction are perpendicular to each other. Along the third direction, a portion of the plurality of first tabs are located on one side of the first electrode terminal and another portion of the first tabs are located on the other side of the first electrode terminal.

[0064] In the above technical solution, by setting a portion of the first tabs in the third direction to be located on one side of the first electrode terminal and another portion of the first tabs in the third direction to be located on the other side of the first electrode terminal in the third direction, the first electrode terminal is provided with first tabs on both sides in the third direction, and the first electrode terminal is located between two adjacent first tabs in the third direction. The battery cell with this structure can optimize the layout between the first electrode terminal and the multiple first tabs, and can realize that the first electrode terminal and the first tabs can share space in the first direction. On the other hand, it can realize that the multiple first tabs are a structure that guides the current from the two sides of the first electrode terminal in the third direction through the first current collector, thereby shortening the current path between the multiple first tabs and the first electrode terminal, which is beneficial to reducing the internal resistance of the battery cell and reducing the current area requirement of the first current collector, so as to optimize the thickness of the first current collector.

[0065] In some embodiments, the housing has a first wall and a second wall connected to each other, the first electrode terminal is disposed on the second wall, the thickness direction of the second wall is parallel to a third direction, and the first direction, the second direction and the third direction are perpendicular to each other; the first current collector includes an electrode tab connection portion and a terminal connection portion connected to each other, the electrode tab connection portion is disposed between the main body portion and the first wall in the first direction, and the connection areas of a plurality of sub-electrodes of each first electrode tab are stacked on the side of the electrode tab connection portion away from the main body portion and are welded to the electrode tab connection portion to form a first solder mark portion, and the terminal connection portion is disposed between the main body portion and the second wall in the third direction and is welded to the first electrode terminal to form a second solder mark portion.

[0066] In the above technical solution, the first electrode terminal is disposed on the second wall. By setting the tab connection part of the first current collector to be located between the main body and the first wall in a first direction and welded to the first tab, and setting the terminal connection part of the first current collector to be located between the main body and the second wall in a third direction and welded to the first electrode terminal, the first tab and the first electrode terminal are respectively located on different sides of the main body, so that the first solder mark part and the second solder mark part are also respectively located on different sides of the main body. This enables the welding positions of the first current collector and the first tab and the welding positions of the first current collector and the first electrode terminal to be located on different sides of the main body, thereby reducing the interference between the welding assembly of the first current collector and the first tab and the welding assembly of the first current collector and the first electrode terminal.

[0067] In some embodiments, the tab connection portion and the terminal connection portion are integrally formed; or, the tab connection portion and the terminal connection portion are separately disposed and connected.

[0068] In the above technical solution, by making the tab connection and the terminal connection an integrally formed structure, the current-carrying effect between the tab connection and the terminal connection can be improved, and the connection reliability between the tab connection and the terminal connection can be enhanced, thereby reducing the risk of connection failure during use. By making the tab connection and the terminal connection a separate structure, it is possible to first weld and assemble the tab connection and the first tab, and the terminal connection and the first electrode terminal, before connecting the tab connection and the terminal connection. This optimizes the production process and production cycle, and reduces the welding difficulty between the tab connection and the first tab, and between the terminal connection and the first electrode terminal.

[0069] In some embodiments, the tab connection portion is provided with at least one clearance notch on at least one side in the second direction, and the clearance notch penetrates the tab connection portion along the first direction; the clearance notch corresponds one-to-one with the first tab, and along the first direction, at least a portion of the sub-tab of each first tab passes through one of the clearance notches and extends to the side of the tab connection portion away from the main body.

[0070] In the above technical solution, by providing a clearance notch along the first direction through the tab connection part on one side of the tab connection part along the second direction, and the clearance notch is used for at least part of the sub-tabs of the first tab to pass through, on the one hand, it is convenient for the first tab to bend towards the second direction to the side of the tab connection part away from the main body after passing through the clearance notch, and it can shorten the path length of each sub-tab bending around the tab connection part, which is beneficial to reducing the difficulty of smoothing the bending of the first tab. On the other hand, it can realize that the tab connection part and the first tab share the space in the second direction, which is beneficial to improve the internal space utilization of the battery cell, and it is beneficial to reduce the assembly difficulty of the tab connection part being located between the first wall and the main body.

[0071] In some embodiments, the terminal connection portion is provided with a mounting hole, which penetrates the terminal connection portion along the third direction; the first electrode terminal has a plug portion, at least a portion of which is inserted into the mounting hole along the third direction and welded to the terminal connection portion to form the second solder mark portion.

[0072] In the above technical solution, by providing an assembly hole that penetrates the terminal connection part in a third direction on the terminal connection part, and inserting the insertion part of the first electrode terminal into the assembly hole and welding it to the terminal connection part, the welding assembly between the first electrode terminal and the terminal connection part is realized. The battery cell with this structure can realize the positioning and limiting function between the first electrode terminal and the terminal connection part through the assembly structure of the assembly hole and the insertion part, so as to reduce the risk of displacement or shaking of the first electrode terminal and the terminal connection part during the welding assembly process, which is conducive to improving the welding quality between the first electrode terminal and the terminal connection part, and is also conducive to further improving the connection reliability between the first electrode terminal and the terminal connection part.

[0073] In some embodiments, along the third direction, the first electrode terminal has an abutting surface facing the terminal connection portion, the insertion portion protrudes from the abutting surface, and the abutting surface abuts against the terminal connection portion.

[0074] In the above technical solution, by abutting the abutting surface of the first electrode terminal with the insertion part against the terminal connection part, the positioning and limiting effect between the first electrode terminal and the terminal connection part can be further improved, thereby further reducing the risk of displacement or shaking of the first electrode terminal and the terminal connection part during the welding assembly process, which is conducive to further improving the welding quality between the first electrode terminal and the terminal connection part, and also conducive to further improving the connection reliability between the first electrode terminal and the terminal connection part.

[0075] In some embodiments, the second solder mark is disposed around the connector.

[0076] In the above technical solution, by setting the second solder mark to a structure surrounding the plug-in part, the plug-in part is inserted into the assembly hole and welded to the hole wall to form a ring-shaped second solder mark. The battery cell with this structure can increase the welding area between the first electrode terminal and the terminal connection part, which is beneficial to further improve the connection stability and overcurrent effect between the first electrode terminal and the terminal connection part.

[0077] In some embodiments, the housing further has a third wall, which is disposed opposite to the first wall in the first direction and connected to the second wall. The electrode assembly further includes a second tab, which has opposite polarity to the first tab and is connected to one end of the main body facing the third wall in the first direction. The battery cell further includes a second electrode terminal and a second current collector, the second electrode terminal being disposed in the second wall and the second current collector being disposed within the housing. A portion of the second current collector is located between the main body and the third wall and connected to the second tab, and a portion of the second current collector is located between the main body and the second wall and connected to the second electrode terminal.

[0078] In the above technical solution, the outer casing also has a third wall disposed opposite to the first wall in the first direction, and the second electrode of the electrode assembly is connected to the end of the main body facing the third wall, so as to realize that the electrode assembly has a structure with the first electrode and the second electrode having opposite polarities at both ends in the first direction, thereby reducing the risk of short circuit and interference between the first electrode and the second electrode, and reducing the risk of short circuit and interference between the first current collector and the second current collector, thereby reducing the assembly difficulty of the battery cell while improving the reliability of the battery cell.

[0079] In some embodiments, the electrode assembly includes a plurality of first tabs with the same polarity. The plurality of first tabs are all connected to one end of the main body facing the first wall and are spaced apart along a third direction. The plurality of first tabs are all welded to the first current collector to form the first solder mark. The first direction, the second direction and the third direction are perpendicular to each other.

[0080] In the above technical solution, by setting multiple first tabs with the same polarity and spaced apart along a third direction at one end of the main body facing the first wall, and welding the multiple first tabs to the first current collector to form a first solder mark, the battery cell with this structure can, on the one hand, increase the current flow area and current flow path between the main body and the first current collector to improve the current flow effect between the main body and the first current collector. On the other hand, when some of the first tabs have unstable connection or connection failure with the first current collector, the remaining first tabs can still achieve electrical connection between the main body and the first current collector, thereby effectively improving the stability and service life of the battery cell.

[0081] In some embodiments, in the second direction, the bending direction of the sub-taper of one first electrode is opposite to the bending direction of the sub-taper of the other first electrode.

[0082] In the above technical solution, by setting the bending direction of the sub-taper of one first electrode tab in the second direction to be opposite to that of the bending direction of the sub-taper of another first electrode tab in the second direction, the smoothing bending directions of at least two first electrodes tabs are opposite. The battery cell with this structure can achieve a reverse stacking order of the connection areas of multiple sub-tapers in at least two first electrodes tabs. Since multiple first electrodes tabs and the first current collector are all welded and assembled on the same side, even if the connection area of ​​the sub-tapers near the welding side in the connection area of ​​multiple sub-tapers of each first electrode tab is damaged, the damaged sub-tapers in the two first electrodes tabs with opposite smoothing bending directions can be achieved as sub-tapers connected to different first electrode segments. This ensures that at least one sub-taper among the multiple sub-tapers connected to the first electrode segment is not damaged, and thus the electrical connection between the corresponding first electrode segment and the first current collector can still be satisfied, which is beneficial to improving the overall stability and service life of the battery cell.

[0083] In some embodiments, the electrode assembly is a stacked structure, the main body includes a plurality of first electrode plates and a plurality of second electrode plates, the first electrode plates and the second electrode plates have opposite polarities, and the first electrode plates and the second electrode plates are alternately and stacked along the second direction; the first electrode plate is a first electrode segment, each first electrode segment is connected to a sub-electrode tab at one end near the first wall in the first direction, and each sub-electrode tab is fixedly connected to the first solder mark portion.

[0084] In the above technical solution, the electrode assembly has a stacked structure, so that the first electrode of the main body is a whole first electrode segment. Thus, by connecting at least one sub-electrode to each first electrode segment, each first electrode of the main body can be electrically connected to the first current collector, thereby reducing the risk of failure of some first electrodes of the electrode assembly. In addition, in the structure where the smoothing and bending directions of at least two first electrodes are opposite, it is convenient for the first current collector to weld at least one sub-electrode on each first electrode segment to the first current collector by welding it to different first electrodes.

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

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

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

[0088] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments; Figure 2 Exploded views of the structure of the battery device provided in some embodiments of this application; Figure 3 This is a schematic diagram of the structure of a battery cell provided in some embodiments of this application; Figure 4 Exploded views of the structure of a single battery cell provided in some embodiments of this application; Figure 5 A partial cross-sectional view of a battery cell perpendicular to the second direction, provided for some embodiments of this application; Figure 6 A partial assembly diagram of the electrode assembly and the first current collector of a battery cell provided in some embodiments of this application; Figure 7 This is a partial structural schematic diagram of the electrode assembly of a battery cell provided in some embodiments of this application; Figure 8 A partial cross-sectional view of the electrode assembly of a battery cell provided in some embodiments of this application, perpendicular to a third direction; Figure 9 A schematic diagram showing the connection of the first electrode segment and the sub-electrode of the electrode assembly of a battery cell provided in some embodiments of this application after being unfolded; Figure 10 A cross-sectional view of the main body of the electrode assembly of a battery cell provided in some embodiments of this application, perpendicular to a first direction; Figure 11 A cross-sectional view of the main body of the electrode assembly of a battery cell provided in some embodiments of this application, perpendicular to the first direction, in other embodiments; Figure 12 A front view in a first direction of the electrode assembly of a battery cell provided in some embodiments of this application after the first tab and the first current collector are welded and assembled; Figure 13 A partial cross-sectional view of the electrode assembly and the first current collector of a battery cell provided in some embodiments of this application after being assembled together; Figure 14 A cross-sectional view of a battery cell after its first electrode terminal and first current collector are assembled together, according to some embodiments of this application; Figure 15 Exploded views of the battery cell structure provided in some embodiments of this application; Figure 16 A partial cross-sectional view of a battery cell perpendicular to a third direction, provided for some embodiments of this application; Figure 17 Exploded views of the battery cell structure provided in other embodiments of this application; Figure 18 A partial cross-sectional view of a battery cell perpendicular to a third direction, provided for other embodiments of this application; Figure 19 A partial cross-sectional view of the electrode assembly and the first current collector of a battery cell provided in other embodiments of this application after being assembled together; Figure 20 This is a schematic diagram of the structure of the first current collector of a battery cell provided in some other embodiments of this application; Figure 21 A cross-sectional view of the first current collector of a battery cell provided in some other embodiments of this application; Figure 22 Exploded views of the battery cell structure are also provided in some embodiments of this application; Figure 23 This application also provides partial cross-sectional views of a battery cell perpendicular to a third direction in some embodiments; Figure 24 This application also provides partial cross-sectional views of the electrode assembly and the first current collector of a battery cell after they are assembled together in some embodiments; Figure 25 This application also provides a schematic diagram of the structure of the first current collector of a battery cell in some embodiments; Figure 26 A partial cross-sectional view of the first current collector of a battery cell in a third direction, provided in some embodiments of this application; Figure 27 Partial cross-sectional view of the bent portion of the first current collector of the battery cell provided in some embodiments of this application in other embodiments; Figure 28 This application also provides cross-sectional views of the first current collector and the first electrode terminal of a battery cell after they are assembled together in some embodiments; Figure 29 Exploded views of the battery cell provided in some embodiments of this application in other embodiments; Figure 30 This is a schematic diagram of the structure of a battery cell provided in some other embodiments of this application; Figure 31 Exploded views of the battery cell structure provided in other embodiments of this application; Figure 32A cross-sectional view of a battery cell perpendicular to the second direction, provided for other embodiments of this application; Figure 33 A partial structural schematic diagram of a battery cell provided for other embodiments of this application; Figure 34 This is a schematic diagram of the structure of the first current collector of a battery cell provided in some other embodiments of this application; Figure 35 This is a cross-sectional view of the first current collector and the first electrode terminal of a battery cell provided in other embodiments of this application after being assembled together.

[0089] Icons: 1000 - Vehicle; 100 - Battery assembly; 10 - Housing; 11 - First housing body; 12 - Second housing body; 20 - Battery cell; 21 - Housing; 21a - First wall; 21b - Second wall; 21c - Third wall; 211 - Housing; 2111 - Opening; 212 - End cap; 22 - First electrode terminal; 221 - Second surface; 222 - Groove; 223 - Fourth surface; 224 - First connecting part; 2241 - First side surface; 2242-Third surface; 2243-Fifth surface; 225-Second connecting part; 226-Third connecting part; 227-Plug-in part; 228-Abutting surface; 23-First current collector; 23a-Foil sheet; 231-Electrode connecting part; 2311-Allowing notch; 232-Terminal connecting part; 2321-Sixth surface; 2322-Seventh surface; 2323-Assembly hole; 233-Bending part; 2331-Through hole; 24 -Electrode assembly; 241-Main body; 241a-Straight region; 241b-Bending region; 2411-First electrode; 2411a-First electrode segment; 2411b-First bending segment; 2412-Second electrode; 2412a-Second electrode segment; 2412b-Second bending segment; 2413-Isolator; 242-First electrode tab; 2421-Sub-electrode tab; 2421a-First sub-electrode tab; 2421b-Second sub-electrode tab; 2421 1-Connection area; 24212-Solder stamp area; 24213-Connection end; 2422-First surface; 243-Second electrode tab; 25-First solder stamp part; 26-Second solder stamp part; 27-Second electrode terminal; 28-Second current collector; 29-Pressure relief component; 30-Heat insulation component; 31-Support component; 32-Sealing component; 200-Controller; 300-Motor; X-First direction; Y-Second direction; Z-Third direction; R-Wounding direction. Detailed Implementation

[0090] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0091] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0092] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0093] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0094] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0095] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0096] In this application, "multiple" means two or more (including two).

[0097] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0098] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0099] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, serves to prevent short circuits to some extent while allowing active ions to pass through.

[0100] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0101] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0102] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, or titanium, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0103] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxides include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM) 622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 At least one of O2 and its modified compounds.

[0104] In some embodiments, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloys, etc. When foamed metal is used as the positive electrode, the surface of the foamed metal may or may not contain a positive electrode active material. As an example, lithium source material, potassium metal, or sodium metal can also be filled and / or deposited within the foamed metal, where the lithium source material is lithium metal and / or a lithium-rich material.

[0105] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0106] As an example, the negative electrode current collector can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, it can be silver-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrodes, or titanium, etc. Foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloys, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0107] As an example, the negative electrode sheet may include a negative electrode current collector and a negative electrode active material disposed on at least one surface of the negative electrode current collector.

[0108] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0109] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as battery negative electrode active materials may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0110] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0111] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0112] In some embodiments, the separator is a separator membrane. The separator membrane can be of various types, and any known porous separator membrane with good chemical and mechanical stability can be selected.

[0113] As an example, the material of the separator may include at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different. The separator may be a separate component located between the positive and negative electrodes, or it may be attached to the surfaces of the positive and negative electrodes.

[0114] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0115] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel-like, or solid. Liquid electrolytes include electrolyte salts and solvents.

[0116] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0117] In some embodiments, the solvent may include at least one selected from ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more selected from ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0118] Among them, the gel electrolyte includes a polymer as the electrolyte backbone network, combined with an ionic liquid - lithium salt.

[0119] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0120] As an example, polymer solid electrolytes can be polyethers (polyoxyethylene), polysiloxanes, polycarbonates, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids-lithium salts, cellulose, etc.

[0121] As an example, inorganic solid electrolytes may include one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphate sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0122] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0123] In some implementations, the electrode assembly has a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0124] In some implementations, the electrode assembly has a stacked structure.

[0125] As an example, multiple positive and negative electrodes can be set, and multiple positive and multiple negative electrodes can be stacked alternately.

[0126] As an example, multiple positive electrode plates can be provided, and negative electrode plates can be folded to form multiple stacked folded segments, with a positive electrode plate sandwiched between adjacent folded segments.

[0127] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0128] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0129] As an example, the separators can be continuously arranged, either by folding or rolling between any adjacent positive or negative electrode plates.

[0130] In some embodiments, the electrode assembly has tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0131] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0132] As an example, the battery cell can be a pouch battery cell or a battery cell of other shapes. Prismatic battery cells include, but are not limited to, square battery cells, blade-shaped battery cells, and multi-prism batteries, such as hexagonal prism batteries.

[0133] The battery device mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells, which are connected in series, parallel, or mixed connections via a busbar.

[0134] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells; as an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells into a single module. As an example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0135] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cell assemblies housed within the housing.

[0136] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0137] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0138] As an example, the enclosure may include a first enclosure body and a second enclosure body. The first enclosure body and the second enclosure body are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, which can be either sealed or unsealed. The first enclosure body may be a top cover or a bottom plate.

[0139] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0140] As an example, the housing can be part of the vehicle's chassis structure. For instance, the housing's roof can be at least part of the vehicle's floor, or the housing's frame can be at least part of the vehicle's crossbeams and longitudinal beams.

[0141] In some embodiments, the battery device refers to an energy storage device, which includes a housing with a door on at least one side. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0142] Battery devices possess outstanding advantages such as high energy density, low environmental pollution, high power density, long service life, wide applicability, and low self-discharge coefficient, making them an important component of today's new energy development. The development of battery technology must simultaneously consider multiple design factors, such as performance parameters like energy density, cycle life, discharge capacity, and charge / discharge rate. Furthermore, the reliability of the battery device must also be taken into account.

[0143] For a typical battery cell, the battery cell includes a casing and an electrode assembly and a current collector housed within the casing. Correspondingly, the casing includes a shell and an end cap that are assembled together. The electrode assembly has tabs formed on the end facing the end cap. Each tab includes multiple sub-tabs stacked together and of the same polarity. The end cap also has electrode terminals electrically connected to the tabs of the electrode assembly. The electrode terminals are connected to the tabs via the current collector to realize the input or output of electrical energy from the battery cell. In related technologies, to reduce the difficulty of forming the tabs and assembling the current collector and the tabs, especially in prismatic battery cells, multiple sub-tabs are usually pre-welded together before being welded to the current collector. Then, the current collector is welded to the electrode terminals, and finally... The tabs are bent to facilitate the assembly of the end caps and the casing. However, in this type of battery cell, the multiple sub-tabs are pre-welded and assembled with the current collector before bending. Because the multiple sub-tabs are pre-welded and fixed before bending, they cannot adapt to the length changes caused by bending. This can lead to local stress concentration or local bulging of the sub-tabs, making them prone to cracking or breakage during assembly or use. Furthermore, the outermost sub-tab after bending is particularly susceptible to warping and cracking or insufficient welding area during welding, which can result in unstable connections or connection failures during battery cell use, thus hindering the improvement of battery cell stability and reliability.

[0144] Based on the above considerations, in order to solve the problem of low stability and reliability of battery cells, this application provides a battery cell including a casing, a first electrode terminal, a first current collector, and at least one electrode assembly. The casing has a first wall, the thickness direction of which is parallel to a first direction. The first electrode terminal is disposed in the casing. The electrode assembly is housed within the casing and includes a main body and a first tab. The main body includes a plurality of first electrode segments stacked along a second direction and having the same polarity. The first tab includes a plurality of sub-tabs stacked together. Each sub-tab of each first tab is connected to one end of a first electrode segment near the first wall, and the sub-tabs are bent toward the second direction, which is perpendicular to the first direction. At least a portion of the first current collector is disposed between the main body and the first wall, and the first current collector is connected to the first electrode terminal. Along the first direction, the sub-tab has a connection area located on the side of the first current collector opposite to the main body. The connection areas of multiple sub-tabs of each first tab are stacked and welded to the first current collector to form at least one first solder mark. The first tab has a first surface opposite to the main body. At least a portion of each first solder mark extends from the first surface through at least a portion of the connection area and into the first current collector. Two adjacent connection areas are fixedly connected only by the first solder mark. Among the multiple connection areas, the dimension of the connection area furthest from the main body in the second direction is greater than the dimension of the connection area closest to the main body in the second direction.

[0145] In this type of battery cell, multiple sub-tabs of the first electrode tab are bent toward the second direction. The connection areas of the multiple sub-tabs are stacked along the first direction on the side of the first current collector component away from the main body and welded to the first current collector component to form a first solder mark. At least part of the first solder mark extends from the first surface of the first electrode tab into the first current collector component. This makes the connection area of ​​the first electrode tab located on the side of the first current collector component away from the main body and welded to the first electrode tab and the first current collector component in the first direction, thereby achieving the assembly connection between the first electrode tab and the first current collector component. Two adjacent sub-tabs are fixedly connected only through the first solder mark. This battery cell structure allows for the elimination of the need for fixed connection or pre-welding of the multiple sub-tabs of the first electrode tab after the first electrode tab is bent toward the second direction and before the connection area of ​​the first electrode tab is stacked and welded to the first current collector component. This facilitates the initial assembly of the first electrode tab and the first current collector component. After the multiple sub-tabs of the first electrode are smoothed and bent, the first electrode and the first current collector are welded together. This allows the multiple sub-tabs to move and shift relative to each other during the smoothing and bending process of the first electrode. This enables each sub-tab to adapt to the length changes caused by bending, reducing local stress concentration or bulging of the sub-tabs during the smoothing and bending process. This effectively improves the welding quality between the first electrode and the first current collector and effectively mitigates the phenomenon of cracking or breakage of the sub-tabs during assembly or use. This reduces the risk of unstable connection and connection failure between the first electrode and the first current collector during use, which is beneficial to improving the stability and reliability of the battery cell. On the other hand, it reduces the welding difficulty between the smoothed and bent first electrode and the first current collector and facilitates the smoothing and bending of the multiple sub-tabs of the first electrode based on the first current collector, thus reducing the bending difficulty of the sub-tabs. Furthermore, since the sub-tab closest to the first surface in the first electrode tab is easily damaged during welding, the size of the connection area furthest from the main body in the second direction among the multiple stacked connection areas is set to be larger than the size of the connection area closest to the main body in the second direction. This makes the area of ​​the connection area furthest from the main body relatively larger, thereby increasing the weldable area between the sub-tab closest to the first surface in the first electrode tab and the first current collector. This helps to mitigate the phenomenon of reduced effective connection area or connection failure between the sub-tab closest to the first surface in the first electrode tab and the first current collector due to damage during welding, and is beneficial to improving the overcurrent reliability between the sub-tab closest to the first surface in the first electrode tab and the first current collector.

[0146] The battery cells disclosed in this application can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft. A power system for such an electrical device can be constructed using battery cells and battery devices disclosed in this application. This helps to alleviate the problem of unstable or failed connections that easily occur during the use of battery cells, thereby improving the stability and reliability of battery cell usage.

[0147] This application provides an electrical device that uses a single battery cell or battery assembly as a power source. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0148] For ease of explanation, the following embodiments will be described using a vehicle as an example of an electrical device according to an embodiment of this application.

[0149] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of this application. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery device 100 is installed inside the vehicle 1000. The battery device 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to supply power to the vehicle 1000; for example, the battery device 100 can serve as the operating power source or general power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 controls the battery device 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during startup, navigation, and driving.

[0150] In some embodiments of this application, the battery device 100 can not only serve as the operating power or power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0151] Please refer to Figure 2 and Figure 3 , Figure 2 This is an exploded view of the structure of the battery device 100 provided in some embodiments of this application. Figure 3 This is a schematic diagram of the structure of a battery cell 20 provided in some embodiments of this application. The battery device 100 includes a housing 10 and battery cells 20, which are housed within the housing 10.

[0152] The housing 10 provides assembly space for the battery cell 20, and can adopt various structures. In some embodiments, the housing 10 may include a first housing body 11 and a second housing body 12, which overlap each other, and together define an assembly space for accommodating the battery cell 20. The second housing body 12 may be a hollow structure open at one end, and the first housing body 11 may be a plate-like structure, with the first housing body 11 covering the open side of the second housing body 12 so that the first housing body 11 and the second housing body 12 together define the assembly space; alternatively, the first housing body 11 and the second housing body 12 may both be hollow structures open on one side, with the open side of the first housing body 11 covering the open side of the second housing body 12.

[0153] Of course, the box 10 formed by the first box body 11 and the second box body 12 can be of various shapes, such as a cylinder, a cuboid, or a cube. For example, in... Figure 2 In the middle, the shape of box 10 is a cuboid.

[0154] In the battery device 100, there can be one or more battery cells 20 disposed within the housing 10. When there are multiple battery cells 20 disposed within the housing 10, they can be connected in series, in parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells 20 are connected in both series and parallel configurations. Multiple battery cells 20 can be directly connected in series, in parallel, or in a mixed configuration, and then the entire assembly of the multiple battery cells 20 is housed within the housing 10. Alternatively, the battery device 100 can also consist of multiple battery cells 20 first connected in series, in parallel, or in a mixed configuration to form battery modules, and then multiple battery modules are connected in series, in parallel, or in a mixed configuration to form a whole, which is then housed within the housing 10.

[0155] In some embodiments, the battery device 100 may also include other structures. For example, the battery device 100 may also include a busbar for connecting multiple battery cells 20 to achieve electrical connection between the multiple battery cells 20.

[0156] Each battery cell 20 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited to these. The battery cell 20 can be in the form of a cuboid, a prism, or other shapes. For example, in... Figure 3 In the middle, the battery cell 20 has a cuboid structure.

[0157] According to some embodiments of this application, refer to Figure 3 Please refer to further details. Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Figure 9 and Figure 10 , Figure 4 This is an exploded view of the structure of a battery cell 20 provided in some embodiments of this application. Figure 5 This is a partial cross-sectional view of a battery cell 20 provided in some embodiments of this application, perpendicular to the second direction Y. Figure 6 This is a partial assembly diagram of the electrode assembly 24 and the first current collector 23 of the battery cell 20 provided in some embodiments of this application. Figure 7 This is a partial structural diagram of the electrode assembly 24 of the battery cell 20 provided in some embodiments of this application. Figure 8 This is a partial cross-sectional view of the electrode assembly 24 of the battery cell 20 provided in some embodiments of this application, perpendicular to a third direction Z. Figure 9 This is a schematic diagram showing the unfolded connection of the first electrode segment 2411a and the sub-electrode tab 2421 of the electrode assembly 24 of the battery cell 20 provided in some embodiments of this application. Figure 10This is a cross-sectional view of the main body 241 of the electrode assembly 24 of a battery cell 20 provided in some embodiments of this application, perpendicular to the first direction X. This application provides a battery cell 20, which includes a housing 21, a first electrode terminal 22, a first current collector 23, and at least one electrode assembly 24. The housing 21 has a first wall 21a, the thickness direction of which is parallel to the first direction X. The first electrode terminal 22 is disposed in the housing 21. The electrode assembly 24 is housed within the housing 21 and includes a main body 241 and a first tab 242. The main body 241 includes a plurality of first electrode segments 2411a stacked along a second direction Y and having the same polarity. The first tab 242 includes a plurality of sub-tabs 2421 stacked together. Each sub-tab 2421 of each first tab 242 is connected to one end of a first electrode segment 2411a near the first wall 21a, and the sub-tab 2421 is bent toward the second direction Y, which is perpendicular to the first direction X. At least a portion of the first current collector 23 is disposed between the main body 241 and the first wall 21a, and the first current collector 23 is connected to the first electrode terminal 22. Along the first direction X, the sub-tab 2421 has a connection area 24211 located on the side of the first current collector 23 away from the main body 241. The connection areas 24211 of the plurality of sub-tabs 2421 of each first tab 242 are stacked and welded to the first current collector 23 to form at least one first solder mark 25. The first tab 242 has a first surface 2422 away from the main body 241. At least a portion of each first solder mark 25 extends from the first surface 2422 through at least a portion of the connection area 24211 and into the first current collector 23. Two adjacent connection areas 24211 are fixedly connected only by the first solder mark 25. Among the plurality of connection areas 24211, the dimension of the connection area 24211 furthest from the main body 241 in the second direction Y is greater than the dimension of the connection area 24211 closest to the main body 241 in the second direction Y.

[0158] The outer shell 21 can also be used to contain electrolytes, such as electrolyte solution. The outer shell 21 can have various structural forms, such as a cuboid. Similarly, the outer shell 21 can be made of various materials, such as copper, iron, aluminum, steel, or aluminum alloy.

[0159] In some embodiments, the housing 21 can be a sealed structure or a non-sealed structure. As an example, when the housing 21 is a sealed structure, it can protect the electrode assembly 24 and prevent, to some extent, electrolyte leakage. When the housing 21 is a non-sealed structure, it can still protect the electrode assembly 24, and a sealing bag may be included between the housing 21 and the electrode assembly 24 to encapsulate the electrode assembly 24 and the electrolyte.

[0160] Optionally, the housing 21 may include a housing 211 and an end cap 212. The housing 211 has an internal cavity for accommodating the electrode assembly 24 and has an opening 2111. That is, the housing 211 is a hollow structure with an opening 2111 at one end. The end cap 212 covers the opening 2111 of the housing 211 and forms a sealed connection to form a sealed space for accommodating the electrode assembly 24 and the electrolyte.

[0161] The housing 211 includes a bottom wall and a side wall. The bottom wall is disposed opposite to the end cap 212. The side wall surrounds the bottom wall, and one end of the side wall is connected to the bottom wall, while the other end forms an opening 2111.

[0162] It should be noted that the first wall 21a of the outer casing 21 can be the end cap 212 of the outer casing 21, or it can be a wall of the housing 211 of the outer casing 21. As an example, in Figure 3 and Figure 4 In this embodiment, the first wall 21a is the end cap 212. Of course, the structure of the battery cell 20 is not limited to this. In other embodiments, the first wall 21a can also be the bottom wall of the housing 211 and the end cap 212 that are disposed opposite to each other, or the first wall 21a can also be the side wall of the housing 211 and the end cap 212 that are adjacent to each other and connected to each other.

[0163] The housing 211 can have various shapes, such as a cuboid or prism structure. The shape of the housing 211 can be determined according to the specific shape of the electrode assembly 24. For example, in... Figure 3 and Figure 4 In the middle, the shell 211 has a cuboid structure, and correspondingly, the end cap 212 has a rectangular plate structure.

[0164] Of course, it is understandable that the outer casing 21 is not limited to the structure described above. The outer casing 21 can also be other structures. For example, the outer casing 21 can include a housing 211 and two end caps 212. The housing 211 is a hollow structure with openings 2111 formed on both opposite sides. One end cap 212 is fitted onto one opening 2111 of the housing 211 and forms a sealed connection to form a sealed space for accommodating the electrode assembly 24 and the electrolyte. That is, the housing 211 has openings 2111 on both opposite sides, and the two end caps 212 are fitted onto both sides of the housing 211 to close the corresponding openings 2111.

[0165] In this embodiment of the application, the electrode assembly 24 includes a main body 241, a first tab 242, and a second tab 243. The main body 241 is the main component of the electrode assembly 24 for chemical reactions to occur inside the battery cell 20. The first tab 242 and the second tab 243 have opposite polarities. The first tab 242 and the second tab 243 are both connected to the main body 241 and are spaced apart.

[0166] The main body 241 of the electrode assembly 24 includes a first electrode 2411, a second electrode 2412, and a separator 2413. The first electrode 2411 and the second electrode 2412 have opposite polarities, i.e., the first electrode 2411 and the second electrode 2412 are the positive electrode and the negative electrode of the electrode assembly 24, respectively. Correspondingly, a first tab 242 is connected to the first electrode 2411, and a second tab 243 is connected to the second electrode 2412. Optionally, the main body 241 of the electrode assembly 24... The structure can be varied. The main body 241 of the electrode assembly 24 can be a wound structure formed by winding the first electrode 2411, the second electrode 2412 and the separator 2413, or a stacked structure formed by alternately stacking the first electrode 2411, the second electrode 2412 and the separator 2413. The separator 2413 is disposed between the first electrode 2411 and the second electrode 2412 to insulate and isolate the first electrode 2411 and the second electrode 2412.

[0167] For example, the separator 2413 is a separator membrane, and the main material of the separator membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.

[0168] Optionally, in Figure 4 and Figure 5 In this embodiment, the first electrode 242 and the second electrode 243 are both connected to the same end of the main body 241 in the first direction X. Of course, in other embodiments, the first electrode 242 and the second electrode 243 may also be structures that are respectively connected to the two ends of the main body 241 in the first direction X.

[0169] For example, the first electrode tab 242 is connected to the end of the first electrode plate 2411 facing the first wall 21a in the first direction X, and the second electrode tab 243 is connected to the end of the second electrode plate 2412 facing the first wall 21a in the first direction X.

[0170] The first tab 242 of the electrode assembly 24 is a multilayer metal foil structure connected to one end of the first electrode 2411 in the first direction X. That is, the first tab 242 includes a plurality of sub-tabs 2421 stacked together, and each layer of metal foil is a sub-tab 2421. Similarly, the second tab 243 of the electrode assembly 24 is a multilayer metal foil structure connected to one end of the second electrode 2412 in the first direction X. It should be noted that the first tab 242 and the first electrode 2411 can be separate structures. For example, the first tab 242 and the first current collector of the first electrode 2411 can be welded together. Of course, the first tab 242 and the first electrode 2411 can also be integrally formed. For example, the first current collector of the first tab 242 and the first electrode 2411 can be formed by integrally cutting the same metal foil to form the first tab 242 and the first current collector. Similarly, the second tab 243 and the second electrode 2412 can be separate structures. For example, the second tab 243 and the second current collector of the second electrode 2412 can be welded together. Of course, the second tab 243 and the second electrode 2412 can also be integrally formed. For example, the second current collector of the second tab 243 and the second electrode 2412 can be formed by integrally cutting the same metal foil to form the second tab 243 and the second current collector.

[0171] The first electrode tab 242 includes a plurality of sub-electrodes 2421 stacked together. Each sub-electrode 2421 of each first electrode tab 242 is connected to the end of a first electrode segment 2411a near the first wall 21a. That is, the first electrode tab 242 is disposed at the end of the main body 241 facing the first wall 21a in the first direction X. The sub-electrodes 2421 in the first electrode tab 242 are connected to the end of the corresponding first electrode segment 2411a near the first wall 21a in the first direction X. And one sub-electrode 2421 in each first electrode tab 242 is connected to one first electrode segment 2411a, so that the positions where the plurality of sub-electrodes 2421 of each first electrode tab 242 are connected to the main body 241 are arranged at intervals along the second direction Y. It should be noted that in embodiments where there are multiple first electrodes 242, each of the multiple first electrodes 242 is disposed at the end of the main body 241 facing the first wall 21a in the first direction X, and the multiple first electrodes 242 are arranged at intervals along the third direction Z. Correspondingly, it can be a structure in which the first electrode segment 2411a is connected to only one sub-electrode 2421 of one first electrode 242, or it can be a structure in which the first electrode segment 2411a is connected to one sub-electrode 2421 of some first electrodes 242, or it can be a structure in which the first electrode segment 2411a is connected to one sub-electrode 2421 of each first electrode 242.

[0172] Sub-electrode 2421 bends toward the second direction Y, and portions of multiple sub-electrode 2421 are stacked along the first direction X. That is, the sub-electrode 2421 is a structure in which the extension direction from one end connected to the first pole segment 2411a to the end away from the first pole segment 2411a changes from extending along the first direction X to extending along the second direction Y. It should be noted that the sub-electrode 2421 can be a structure that bends toward the second direction Y to only one side, so that the sub-electrode 2421 includes only one bending position. Of course, the sub-electrode 2421 can also be a structure that first bends toward the second direction Y to one side and then bends toward the second direction Y to the other side, so that the sub-electrode 2421 is a continuously bent structure and includes two bending positions.

[0173] In this embodiment, the main body 241 of the electrode assembly 24 has a flat region 241a, that is, the flat region 241a is the flat portion of the main body 241 of the electrode assembly 24. For example, in Figure 10 In this configuration, the electrode assembly 24 has a wound structure, and the central axis of the winding of the electrode assembly 24 extends along the first direction X. Correspondingly, the main body 241 also has two bending regions 241b, which are respectively connected to the two opposite ends of the straight region 241a in the third direction Z. The first direction X, the second direction Y, and the third direction Z are perpendicular to each other. Of course, if the electrode assembly 24 has a stacked structure, refer to... Figure 11 As shown, Figure 11 In other embodiments, the main body 241 of the electrode assembly 24 of the battery cell 20 provided in some embodiments of this application is a cross-sectional view perpendicular to the first direction X. In this case, the main body 241 of the electrode assembly 24 is entirely a flat region 241a, that is, the main body 241 of the electrode assembly 24 only includes the flat region 241a.

[0174] The first electrode 2411 includes a first electrode segment 2411a located in the flat region 241a, and the second electrode 2412 includes a second electrode segment 2412a located in the flat region 241a. Correspondingly, the flat region 241a of the electrode assembly 24 includes multiple first electrode segments 2411a and multiple second electrode segments 2412a, and the first electrode segments 2411a and the second electrode segments 2412a are stacked and alternately arranged along the second direction Y. It should be noted that if the electrode assembly 24 is a wound structure, see [reference needed]. Figure 11As shown, the first pole segment 2411a is the straight portion of the first pole piece 2411 located in the straight region 241a, and the second pole segment 2412a is the straight portion of the second pole piece 2412 located in the straight region 241a. Correspondingly, the first electrode 2411 includes a plurality of first electrode segments 2411a located in the flat region 241a, and the second electrode 2412 includes a plurality of second electrode segments 2412a located in the flat region 241a. The first electrode 2411 also includes a plurality of first bent segments 2411b located in the bent region 241b, and the second electrode 2412 also includes a plurality of second bent segments 2412b located in the bent region 241b. In the winding direction R of the electrode assembly 24, the first bent segments 2411b connect two adjacent first electrode segments 2411a, and the first bent segments 2411b and the first electrode segments 2411a are alternately arranged. Similarly, in the winding direction R of the electrode assembly 24, the second bent segments 2412b connect two adjacent second electrode segments 2412a, and the second bent segments 2412b and the second electrode segments 2412a are alternately arranged.

[0175] It should be noted that if the electrode assembly 24 is a stacked structure, the electrode assembly 24 includes a plurality of first electrode plates 2411 and a plurality of second electrode plates 2412. The first electrode plates 2411 and the second electrode plates 2412 are alternately stacked along the second direction Y. Correspondingly, the first electrode segment 2411a is the first electrode plate 2411 and the second electrode segment 2412a is the second electrode plate 2412.

[0176] It should be noted that if the electrode assembly 24 is a wound structure, each of the multiple first electrode segments 2411a in the main body 241 may be connected to a sub-electrode tab 2421, or only some of the first electrode segments 2411a may be connected to a sub-electrode tab 2421; if the electrode assembly 24 is a stacked structure, each of the first electrode segments 2411a may be connected to a sub-electrode tab 2421.

[0177] The battery cell 20 includes at least one electrode assembly 24, meaning that the number of electrode assemblies 24 housed within the housing 21 can be one or more. For example, in... Figure 4 In this structure, the electrode assembly 24 has a wound structure. Correspondingly, there can be one or more electrode assemblies 24 housed within the outer casing 21. After the first electrode 2411 and the second electrode 2412 of the main body portion 241 of each electrode assembly 24 are wound and formed, the tail end of the separator 2413 of the main body portion 241 of each electrode assembly 24 will continue to be wound and correspondingly cover the outside of the first electrode 2411 and the second electrode 2412 to form a single main body portion 241 of the electrode assembly 24. See [link to relevant documentation]. Figure 4As shown, only one electrode assembly 24 is disposed within the casing 21 of the battery cell 20. Of course, in other embodiments, the electrode assembly 24 disposed within the casing 21 can be two, three, four, five, six, seven, eight or more, and multiple electrode assemblies 24 are stacked along the second direction Y. It should be noted that if the electrode assembly 24 is a stacked structure, the number of electrode assemblies 24 disposed within the casing 21 is usually one.

[0178] In this embodiment, the first electrode terminal 22 serves as the first tab 242 of the electrode assembly 24, acting as the output or input electrode of the battery cell 20, thereby enabling the output or input of electrical energy from the battery cell 20.

[0179] The structure in which the first electrode terminal 22 is disposed on the housing 21 can also be varied, for example, see Figure 3 and Figure 4 As shown, the first electrode terminal 22 may be disposed on the first wall 21a, such that the first electrode terminal 22 and the first tab 242 are both located on the same side of the main body 241 in the first direction X. Of course, in some embodiments, the first electrode terminal 22 may also be disposed on other walls of the housing 21 besides the first wall 21a, that is, the first electrode terminal 22 and the first tab 242 are respectively located on different sides of the main body 241.

[0180] As an example, the first electrode terminal 22 is inserted into the first electrode lead-out hole of the housing 21 and is insulated and installed on the housing 21. That is to say, there is no electrical connection between the first electrode terminal 22 and the housing 21. It should be noted that the first electrode lead-out hole is a structure that penetrates one wall of the housing 21 and connects the inner and outer sides of the housing 21.

[0181] In this embodiment, the first current collector 23 serves to connect the first electrode terminal 22 and the first tab 242 to achieve electrical connection between the first electrode terminal 22 and the electrode assembly 24, thereby reducing the difficulty of connecting the first electrode terminal 22 and the first tab 242.

[0182] In this embodiment, at least a portion of the first current collector 23 is disposed between the main body 241 and the first wall 21a. That is, the first current collector 23 can be partially disposed between the main body 241 and the first wall 21a, or it can be entirely disposed between the main body 241 and the first wall 21a. In an embodiment where the first electrode terminal 22 is disposed on the first wall 21a, such that the first electrode terminal 22 and the first tab 242 are both located on the same side of the main body 241 in the first direction X, the first current collector 23 can be partially disposed between the main body 241 and the first wall 21a, or it can be entirely disposed between the main body 241 and the first wall 21a. In an embodiment where the first electrode terminal 22 can also be disposed on one of the multiple walls of the housing 21 other than the first wall 21a, such that the first electrode terminal 22 and the first tab 242 are located on different sides of the main body 241, the first current collector 23 can only be partially disposed between the main body 241 and the first wall 21a.

[0183] The first current collector 23 is connected to the electrode terminal so that the first electrode terminal 22 is electrically connected to the first tab 242 of the electrode assembly 24 through the first current collector 23. Optionally, the connection structure between the first current collector 23 and the first electrode terminal 22 can be various, such as welding connection, abutment or snap-fit ​​connection, etc.

[0184] Along the first direction X, the sub-taper 2421 has a connection area 24211 located on the side of the first current collector 23 away from the main body 241. That is, the connection area 24211 of the sub-taper 2421 is the part where the orthographic projection of the sub-taper 2421 on the side of the first current collector 23 away from the main body 241 in the first direction X overlaps with the orthographic projection of the first current collector 23 in the projection plane perpendicular to the first direction X.

[0185] The connection areas 24211 of the plurality of sub-taps 2421 of each first electrode tab 242 are stacked and welded to the first current collector 23 to form at least one first solder mark 25. That is, in the same first electrode tab 242, the portions of the plurality of sub-taps 2421 located on the side of the first current collector 23 away from the main body 241 are stacked together along the first direction X and are all welded to the first current collector 23 to form the first solder mark 25, so that the first electrode tab 242 has a portion located on the side of the first current collector 23 away from the main body 241, and this portion of the first electrode tab 242 and the first current collector 23 are connected by the first solder mark 25. Correspondingly, the first solder mark 25 is the area where the portion of the first electrode tab 242 and the first current collector 23 are welded together to form a fused area or a solder mark area.

[0186] The first tab 242 has a first surface 2422 facing away from the main body 241. At least a portion of each first solder mark 25 extends from the first surface 2422 through at least a portion of the connection area 24211 and into the first current collector 23. That is, in the first direction X, the first solder mark 25 is a structure that extends at least a portion from the first surface 2422 of the first tab 242 facing away from the main body 241 toward the main body 241 and into the first current collector 23, such that the outer surface of the first solder mark 25 facing away from the main body 241 in the first direction X is connected to the first surface 2422, and such that in the projection plane perpendicular to the first direction X, the orthographic projection of the portion of the first solder mark 25 connected to the first current collector 23 can be a structure located within the orthographic projection of the portion of the first solder mark 25 connected to the first tab 242, i.e., when welding and assembling the first tab 242 and the first current collector... When component 23 is used, the welding equipment is a structure that welds and assembles the first electrode 242 and the first current collector 23 from the side of the first electrode 242 away from the main body 241 in the first direction X. The first solder mark 25 is a structure that first passes through the connection area 24211 of multiple sub-electrodes 2421 and then extends into the first current collector 23. The portion of the first solder mark 25 located in the first electrode 242 and the portion of the first solder mark 25 located in the first current collector 23 are arranged and connected along the first direction X. Each first solder mark 25 is fixedly connected to the connection area 24211 of at least a portion of the sub-electrodes 2421. Correspondingly, the first solder mark 25 can be a structure that sequentially connects the connection areas 24211 of some sub-electrodes 2421 in the first direction X, or it can be a structure that sequentially connects the connection areas 24211 of all sub-electrodes 2421 in the first direction X.

[0187] Optionally, the outer surface of the first solder mark 25 that is away from the main body 241 in the first direction X can be a structure that is flush with the first surface 2422, or a structure in which part of the first solder mark 25 protrudes from the first surface 2422.

[0188] The two adjacent sub-tabs 2421 are fixedly connected only through the first solder mark 25. That is, the two adjacent sub-tabs 2421 are stacked and fixedly connected only through the first solder mark 25, without any other fixing structure. Before the first current collector 23 and the first tab 242 are welded to form the first solder mark 25, the two adjacent sub-tabs 2421 are unfixed to each other and can move and separate relative to each other.

[0189] Among the multiple connection regions 24211, the dimension of the connection region 24211 furthest from the main body 241 in the second direction Y is greater than the dimension of the connection region 24211 closest to the main body 241 in the second direction Y. That is, among the multiple connection regions 24211 stacked on the side of the first current collector 23 away from the main body 241 in the first direction X, the length dimension of the outermost connection region 24211 in the second direction Y is larger than the length dimension of the connection region 24211 directly abutting the first current collector 23 in the second direction Y. This makes the connection region 24211 furthest from the main body 241 have a structure that extends beyond the end of the connection region 24211 closest to the main body 241 in the second direction Y, away from the end of the first pole segment 2411a in its extension direction. For ease of description, the plurality of sub-taps 2421 of the first electrode 242 include a first sub-taps 2421a and a second sub-taps 2421b. The connection region 24211 of the first sub-taps 2421a is the connection region 24211 closest to the main body 241 in the first direction X among the plurality of connection regions 24211. The connection region 24211 of the second sub-taps 2421b is the connection region 24211 furthest from the main body 2411 in the first direction X among the plurality of connection regions 24211. Correspondingly, the second sub-taps 2421b extends from the end of the first sub-taps 2421a away from the first electrode segment 2411a in the second direction Y.

[0190] For example, in the embodiments of this application, the first solder mark 25 is a solder mark structure formed by laser welding of the first current collector 23 and the first electrode tab 242.

[0191] For example, the material of the first current collector 23 can be various, such as copper, iron, aluminum, steel or aluminum alloy.

[0192] In this embodiment, the first current collector 23 and the first electrode terminal 22 are welded together, and the first current collector 23 and the first electrode terminal 22 are welded together to form a second solder mark 26. For example, the second solder mark 26 is a solder mark structure formed by laser welding of the first current collector 23 and the first electrode terminal 22.

[0193] In some embodiments, the battery cell 20 may further include a second electrode terminal 27 electrically connected to the second tab 243 of the electrode assembly 24, such that the second electrode terminal 27 and the first electrode terminal 22 can cooperate to input or output electrical energy of the battery cell 20.

[0194] The second electrode terminal 27 is also disposed on the housing 21. Correspondingly, the housing 21 is provided with a second electrode lead-out hole, which penetrates one wall of the housing 21. The second electrode terminal 27 is disposed in the second electrode lead-out hole and is insulatedly mounted on the housing 21. In other words, the second electrode terminal 27 and the housing 21 are not electrically connected.

[0195] As an example, see Figure 4 and Figure 5 As shown, the second electrode terminal 27 is also disposed on the first wall 21a, and the second electrode terminal 27 and the first electrode terminal 22 are arranged at intervals.

[0196] In some embodiments, see Figure 5 As shown, the battery cell 20 may also include a second current collector 28, which serves to connect the second electrode terminal 27 and the second tab 243 to realize the electrical connection between the second electrode terminal 27 and the electrode assembly 24, thereby reducing the difficulty of connecting the second electrode terminal 27 and the second tab 243.

[0197] The connection structure between the second current collector 28 and the second electrode terminal 27, as well as between the second current collector 28 and the second electrode tab 243, can be various, such as welding connection or abutment connection.

[0198] For example, the material of the second current collector 28 can be various, such as copper, iron, aluminum, steel or aluminum alloy.

[0199] It should be noted that the second tab 243 can have the same structure as the first tab 242. Similarly, the assembly structure between the second current collector 28 and the second electrode terminal 27, as well as between the second current collector 28 and the second tab 243, can be the same as the assembly structure between the first current collector 23 and the first electrode terminal 22, as well as between the first current collector 23 and the first tab 242.

[0200] In some embodiments, see Figure 3 and Figure 4 As shown, the battery cell 20 may also include a pressure relief component 29, which is disposed on the housing 21 and is used to release the internal pressure of the battery cell 20 when the internal pressure or temperature of the battery cell 20 reaches a predetermined value.

[0201] For example, the pressure relief component 29 is disposed on the end cap 212 of the housing 21. Of course, in other embodiments, the pressure relief component 29 may also be disposed on the housing 211 of the housing 21. Similarly, the pressure relief component 29 and the housing 21 may be integrally formed or separate. If the pressure relief component 29 and the housing 21 are separate, the pressure relief component 29 may be connected to the housing 21 by welding or other means. Correspondingly, the pressure relief component 29 may be a component such as an explosion-proof valve, explosion-proof disc, gas valve, pressure relief valve, or safety valve. If the pressure relief component 29 and the housing 21 are integrally formed, the pressure relief component 29 is a region on the housing 21 with a weak structure, such as a region on the housing 21 with a groove.

[0202] In this embodiment, a plurality of sub-tabs 2421 of the first tab 242 are bent toward the second direction Y. The connection areas 24211 of the plurality of sub-tabs 2421 are stacked along the first direction X on the side of the first current collector 23 away from the main body 241 and welded together with the first current collector 23 to form a first solder mark 25. At least a portion of the first solder mark 25 is a structure that extends from the first surface 2422 of the first tab 242 into the first current collector 23, such that the connection area 24211 of the first tab 242 is located on the side of the first current collector 23 away from the main body 241 and in the first direction X. The first electrode 242 and the first current collector 23 are welded together on the side of the first electrode 242 away from the first current collector 23 in the X direction, so as to realize the assembly connection between the first electrode 242 and the first current collector 23. Two adjacent sub-electrodes 2421 are fixedly connected only through the first solder mark 25. The battery cell 20 with this structure can realize that after the first electrode 242 is bent towards the second direction Y and before the connection area 24211 of the first electrode 242 is stacked and welded with the first current collector 23, the multiple sub-electrodes 2421 of the first electrode 242 are not welded together. Fixed connections or pre-welding are used to facilitate the smoothing and bending of multiple sub-tips 2421 of the first electrode lug 242 before welding and assembling the first electrode lug 242 and the first current collector 23. This allows the multiple sub-tips 2421 to have relative movement and lateral movement capabilities during the smoothing and bending process of the first electrode lug 2422. This enables each sub-tips 2421 to adapt to the length changes caused by bending during the smoothing and bending process, reducing local stress concentration or local bulging of the sub-tips 2421. This effectively improves the performance of the first electrode lug 242 and the first current collector 23. The welding quality between the first electrode 242 and the first current collector 23 is improved, which can effectively alleviate the phenomenon of cracking or breakage of the sub-tab 2421 during assembly or use, thereby reducing the risk of unstable connection and connection failure between the first electrode 242 and the first current collector 23 during use. This is beneficial to improving the stability and reliability of the battery cell 20. On the other hand, it can reduce the welding difficulty between the first electrode 242 and the first current collector 23 after smoothing and bending, and facilitate the smoothing and bending of multiple sub-tabs 2421 of the first electrode 242 based on the first current collector 23, thereby reducing the bending difficulty of the sub-tabs 2421.Furthermore, since the sub-taper 2421 closest to the first surface 2422 in the first tab 242 is easily damaged during welding, the size of the connection area 24211 furthest from the main body 241 in the second direction Y is set to be larger than the size of the connection area 24211 closest to the main body 241 in the second direction Y. This makes the area of ​​the connection area 24211 furthest from the main body 241 relatively larger, thereby increasing the weldable area between the sub-taper 2421 closest to the first surface 2422 in the first tab 242 and the first current collector 23. This helps to alleviate the phenomenon of reduced effective connection area or connection failure between the sub-taper 2421 closest to the first surface 2422 in the first tab 242 and the first current collector 23 due to damage during welding. This is beneficial to improving the overcurrent reliability between the sub-taper 2421 closest to the first surface 2422 in the first tab 242 and the first current collector 23.

[0203] According to some embodiments of this application, see Figure 6 , Figure 7 and Figure 8 As shown, the connection region 24211 that is furthest from the main body 241 among the multiple connection regions 24211 has the largest size in the second direction Y.

[0204] Among them, the connection region 24211 of the second sub-electrode 2421b is the connection region 24211 that is furthest from the main body 241 in the first direction X among the multiple connection regions 24211. The connection region 24211 that is furthest from the main body 241 among the multiple connection regions 24211 has the largest size in the second direction Y. That is, the size of the connection region 24211 of the second sub-electrode 2421b in the second direction Y is greater than the size of the connection region 24211 of all other sub-electrodes 2421 in the second direction Y, so that the second sub-electrode 2421b extends in the second direction Y beyond the end of all other sub-electrodes 2421 that is furthest from the first pole segment 2411a.

[0205] In this embodiment, by setting the connection area 24211 furthest from the main body 241 among the multiple connection areas 24211 to be the largest in size in the second direction Y, the connection area 24211 furthest from the main body 241 can be welded to the first current collector 23 with the largest area. This further alleviates the phenomenon that the sub-taper 2421 closest to the first surface 2422 in the first tab 242 is damaged during the welding process, resulting in a reduction in the effective connection area or connection failure between it and the first current collector 23. This is beneficial to further improve the overcurrent reliability between the sub-taper 2421 closest to the first surface 2422 in the first tab 242 and the first current collector 23.

[0206] According to some embodiments of this application, please continue to refer to Figure 6 , Figure 7 and Figure 8 As shown, in at least two partially adjacent connection regions 24211, the dimension of the connection region 24211 farther from the main body 241 in the second direction Y is larger than the dimension of the connection region 24211 closer to the main body 241 in the second direction Y. That is, in at least some connection regions 24211, the closer the connection region 24211 is to the first current collector 23 in the first direction X, the smaller its dimension in the second direction Y, so that in the plurality of sub-tabs 2421, the dimensions of the multiple connection regions 24211 stacked in the plurality of sub-tabs 2421 gradually decrease from the connection region 24211 furthest from the main body 241 to the connection region closest to the main body 241.

[0207] For example, in the embodiments of this application, all two adjacent connection areas 24211 have a structure in which the size of the connection area 24211 away from the main body 241 in the second direction Y is greater than the size of the connection area 24211 near the main body 241 in the second direction Y. Of course, in other embodiments, it is also possible that in some two adjacent connection areas 24211, the size of the connection area 24211 away from the main body 241 in the second direction Y is greater than the size of the connection area 24211 near the main body 241 in the second direction Y, and correspondingly, the size of another part of the two adjacent connection areas 24211 in the second direction Y is equal.

[0208] In this embodiment, by setting the size of the connection area 24211 farther from the main body 241 in the second direction Y of at least two partially adjacent connection areas 24211 to be larger than the size of the connection area 24211 closer to the main body 241 in the second direction Y, the size of the multiple stacked connection areas 24211 in the second direction Y gradually decreases from the connection area 24211 furthest from the main body 241 to the connection area closest to the main body 241. The battery cell 20 with this structure can improve the regularity of the multiple sub-tabs 2421 after they are smoothed and stacked on the side of the first current collector 23 away from the main body 241, and facilitate the welding connection of the multiple connection areas 24211 to the first current collector 23. On the other hand, it is easier to realize that the connection area 24211 of each sub-tab 2421 can be welded to the first current collector 23, so as to reduce the phenomenon that the connection area 24211 of some sub-tabs 2421 is not welded to the first current collector 23.

[0209] According to some embodiments of this application, see Figure 8As shown, the plurality of sub-tabs 2421 include a first sub-tab 2421a. The connection region 24211 of the first sub-tab 2421a is the connection region 24211 closest to the main body 241 among the plurality of connection regions 24211. The dimension of the connection region 24211 of the first sub-tab 2421a in the second direction Y is greater than or equal to 5 mm.

[0210] Among them, the connection area 24211 of the first sub-taper 2421a is the connection area 24211 closest to the main body 241 among the multiple connection areas 24211, so that the connection area 24211 of the first sub-taper 2421a is also the connection area 24211 that directly abuts the first current collector 23 among the multiple connection areas 24211. Correspondingly, the size of the connection area 24211 of the first sub-taper 2421a in the second direction Y is greater than or equal to 5mm, that is, the size of the connection area 24211 closest to the first current collector 23 in the first direction X among the multiple connection areas 24211 is greater than or equal to 5mm in the second direction Y.

[0211] exist Figure 8 In the first sub-tab 2421a, the dimension of the connection area 24211 in the second direction Y is L1, that is, L1≥5mm. For example, the dimension L1 of the connection area 24211 in the second direction Y of the first sub-tab 2421a can be 5mm, 5.1mm, 5.2mm, 5.3mm, 5.4mm, 5.5mm, 5.6mm, 5.7mm, 5.8mm, 5.9mm, 6mm, 6.1mm, 6.2mm, 6.3mm, 6.4mm, 6.5mm, 6.6mm, 6.7mm, 6.8mm, 6.9mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm or 11mm, etc.

[0212] In this embodiment, by setting the smallest connection area 24211 in the second direction Y to have a size greater than or equal to 5 mm in the second direction Y, the structure is such that the size of all connection areas 24211 in the second direction Y is at least greater than or equal to 5 mm. This can improve the connectable area of ​​the connection area 24211 with the first solder mark 25 in the second direction Y, which is beneficial to further improve the connection stability and flow area between the sub-electrode tab 2421 and the first current collector 23.

[0213] According to some embodiments of this application, in conjunction with Figure 6 and Figure 8As shown, the plurality of sub-tabs 2421 include a first sub-tab 2421a, the connection region 24211 of the first sub-tab 2421a is the connection region 24211 closest to the main body 241 among the plurality of connection regions 24211, and at least one first solder mark 25 extends beyond the first sub-tab 2421a and away from the first pole segment 2411a in the second direction Y.

[0214] In this embodiment, at least one first solder mark 25 extends beyond the end of the first sub-taper 2421a away from the first pole segment 2411a in the second direction Y. That is, in the projection plane perpendicular to the first direction X, the orthographic projection of at least one first solder mark 25 protrudes beyond the orthographic projection of the end face of the first sub-taper 2421a away from the first pole segment 2411a in the second direction Y. It should be noted that in embodiments where multiple first solder marks 25 are connected to the first pole segment 242, only one first solder mark 25 may extend beyond the end of the first sub-taper 2421a away from the first pole segment 2411a in the second direction Y, or a portion of the first solder marks 25 may extend beyond the end of the first sub-taper 2421a away from the first pole segment 2411a in the second direction Y, or all of the first solder marks 25 may extend beyond the end of the first sub-taper 2421a away from the first pole segment 2411a in the second direction Y.

[0215] In this embodiment, by setting at least one first solder mark 25 in the second direction Y to extend beyond the end of the first sub-tab 2421a that is far from the first pole segment 2411a, the size of the first solder mark 25 in the second direction Y is not limited by the connection area 24211 with the shortest size in the second direction Y, thereby increasing the connection area between the first pole 242 as a whole and the first solder mark 25, and thus further improving the connection stability and flow area between the first pole 242 and the first current collector 23.

[0216] According to some embodiments of this application, in conjunction with Figure 6 , Figure 8 and Figure 9 As shown, the area through which the sub-taper 2421 is traversed by the first solder mark 25 forms a solder mark area 24212. In at least two partially adjacent connection areas 24211, the solder mark area 24212 on the connection area 24211 away from the main body 241 has a larger dimension in the second direction Y than the solder mark area 24212 on the connection area 24211 close to the main body 241 in the second direction Y.

[0217] Among them, the soldering area 24212 is the area through which the sub-electrode 2421 is passed by the corresponding first soldering part 25, and is also the area where the sub-electrode 2421 is connected to the corresponding first soldering part 25, and is also the area where the sub-electrode 2421 and the first current collector 23 are welded together to form the first soldering part 25.

[0218] In two adjacent connection areas 24211, the solder area 24212 on the connection area 24211 farther from the main body 241 has a larger size in the second direction Y than the solder area 24212 on the connection area 24211 closer to the main body 241. That is, in at least some connection areas 24211, the solder area 24212 formed on the connection area 24211 closer to the first current collector 23 in the first direction X has a smaller size in the second direction Y. Correspondingly, in the plurality of sub-tabs 2421, the size of the solder area 24212 formed on the stacked connection areas 24211 in the second direction Y is a structure that gradually decreases from the connection area 24211 farthest from the main body 241 to the connection area closest to the main body 241.

[0219] For example, in the embodiments of this application, in all two adjacent connection areas 24211, the size of the solder area 24212 on the connection area 24211 away from the main body 241 in the second direction Y is greater than the size of the solder area 24212 on the connection area 24211 near the main body 241 in the second direction Y. Of course, in other embodiments, it is also possible that in some two adjacent connection areas 24211, the size of the solder area 24212 on the connection area 24211 away from the main body 241 in the second direction Y is greater than the size of the solder area 24212 on the connection area 24211 near the main body 241 in the second direction Y. Correspondingly, the size of the solder area 24212 on another part of the two adjacent connection areas 24211 is equal in the second direction Y.

[0220] In this embodiment, by setting the size of the solder area 24212 on the connection area 24211 farther from the main body 241 in at least two partially adjacent connection areas 24211 in the second direction Y to be larger than the size of the solder area 24212 on the connection area 24211 closer to the main body 241 in the second direction Y, the size of the solder area 24212 on the stacked connection areas 24211 in the second direction Y gradually decreases from the connection area 24211 farthest from the main body 241 to the connection area closest to the main body 241. On the one hand, since the sub-tabs 2421 farther from the first current collector 23 have a longer current path and greater internal resistance, resulting in relatively poor current stability, the battery cell 20 with this structure can achieve the following: the sub-tabs 2421 farther from the first current collector 23 have a longer current path and greater internal resistance. The larger the welding area between the first current collector 23 and the first current collector 23, the better the internal resistance between each sub-tab 2421 and the first current collector 23 can be balanced, thus balancing the current flow effect between each sub-tab 2421 and the first current collector 23. On the other hand, since the sub-tabs 2421 that are closer to the first surface 2422 are more susceptible to welding damage during the welding process, the battery cell 20 with this structure can achieve a larger welding area between the sub-tabs 2421 that are closer to the first surface 2422 and the first current collector 23. This alleviates the problem that the sub-tabs 2421 that are closer to the first surface 2422 are more susceptible to damage during the welding process, resulting in a reduction in the effective connection area or connection failure between them and the first current collector 23. This improves the connection stability and current flow effect between the first tab 242 and the first current collector 23.

[0221] According to some embodiments of this application, in conjunction with Figure 6 and Figure 8 As shown, the plurality of sub-tabs 2421 include a second sub-tab 2421b, and the connection area 24211 of the second sub-tab 2421b is the connection area 24211 furthest from the main body 241 among the plurality of connection areas 24211. In a projection plane perpendicular to the first direction X, the orthographic projections of all the first solder marks 25 in the same first tab 242 are located within the orthographic projection of the second sub-tab 2421b.

[0222] Among them, the connection area 24211 of the second sub-electrode 2421b is the connection area 24211 furthest from the main body 241 among the multiple connection areas 24211, so that the connection area 24211 of the second sub-electrode 2421b is also the connection area 24211 with the largest distance from the first current collector 23 among the multiple connection areas 24211. Correspondingly, in the projection plane perpendicular to the first direction X, the orthographic projection of all the first solder parts 25 of the same first electrode 242 is located in the orthographic projection of the second sub-electrode 2421b. That is to say, each first solder part 25 on the same first electrode 242 has a structure that first passes through the second sub-electrode 2421b and then passes through other sub-electrode 2421.

[0223] In this embodiment, by setting the orthographic projection of all the first solder marks 25 in the same first tab 242 onto a projection plane perpendicular to the first direction X, all of them are located within the orthographic projection of the second sub-tab 2421b onto a projection plane perpendicular to the first direction X, each first solder mark 25 in the same first tab 242 is designed to first pass through the second sub-tab 2421b before connecting to other sub-tabs 2421 and the first current collector 23. This maximizes the welding area of ​​the second sub-tab 2421b, further mitigating the phenomenon that the second sub-tab 2421b closest to the first surface 2422 in the first tab 242 may be damaged during welding, resulting in a reduction in the effective connection area or connection failure between it and the first current collector 23. This is beneficial for further improving the overcurrent reliability between the second sub-tab 2421b closest to the first surface 2422 in the first tab 242 and the first current collector 23.

[0224] According to some embodiments of this application, see Figure 6 As shown, along the first direction X, at least one first solder mark 25 passes through the connection area 24211 of all the sub-tabs 2421 in the first electrode tab 242. That is, all the sub-tabs 2421 in the first electrode tab 242 are fixedly connected to at least one first solder mark 25. Correspondingly, at least one solder mark area 24212 is formed on each sub-tab 2421 in the first electrode tab 242 (in conjunction with...). Figure 9 (As shown).

[0225] In this embodiment, by setting at least one first solder mark 25 to pass through the connection area 24211 of all sub-taps 2421 in the corresponding first electrode tab 242, the connection area 24211 of all sub-taps 2421 in the first electrode tab 242 is fixedly connected to at least the first solder mark 25, and each sub-taps 2421 in the first electrode tab 242 is welded to the first current collector 23. This can further improve the current flow effect and connection stability between the first electrode tab 242 and the first current collector 23, and reduce the risk of excessively long current flow path or connection failure of the first electrode segment 2411a due to the sub-taps 2421 on some first electrode segments 2411a not being welded to the first current collector 23.

[0226] In some embodiments, see Figure 6 As shown, along the first direction X, the thickness of the portion of the first solder mark 25 extending into the first current collector 23 is T1, and the thickness of the area where the first current collector 23 is connected to the first solder mark 25 is T2, satisfying 0.25≤T1 / T2≤0.75.

[0227] Wherein, T1 is the maximum dimension of the portion of the first solder mark 25 located within the first current collector 23 in the first direction X, and is also the maximum dimension of the portion of the first solder mark 25 connected to the first current collector 23 in the first direction X. Correspondingly, T2 is the thickness of the area where the first current collector 23 is connected to the first solder mark 25, and is also the sum of the minimum distance between the surface of the first current collector 23 facing the main body 241 in the first direction X and the area corresponding to the first solder mark 25 and the first solder mark 25 and T1. Correspondingly, T1 / T2 is the ratio of the depth of the molten pool of the first solder mark 25 within the first current collector 23 to the thickness of the first current collector 23.

[0228] For example, T1 / T2 can be any one of the following point values ​​or a range of values ​​between any two: 0.25, 0.26, 0.27, 0.28, 0.29, 0.3, 0.32, 0.35, 0.38, 0.4, 0.42, 0.45, 0.48, 0.5, 0.52, 0.55, 0.58, 0.6, 0.62, 0.65, 0.68, 0.7, 0.72, or 0.75.

[0229] In this embodiment, on the one hand, the thickness of the portion of the first solder mark 25 extending into the first current collector 23 is set to be greater than or equal to 0.25 times the thickness of the area where the first current collector 23 is connected to the first solder mark 25, so as to increase the welding penetration of the first solder mark 25 in the first current collector 23, thereby improving the current flow effect between the first tab 242 and the first current collector 23, and also improving the connection stability between the first tab 242 and the first current collector 23. On the other hand, the thickness of the portion of the first solder mark 25 extending into the first current collector 23 is set to be less than or equal to 0.75 times the thickness of the area where the first current collector 23 is connected to the first solder mark 25, so as to reduce the risk of the first current collector 23 being burned through and damaging other components.

[0230] According to some embodiments of this application, in conjunction with Figure 5 and Figure 6 As shown, along the first direction X, the thickness of the area where the first current collector 23 is connected to the first solder mark 25 is 0.3mm-4mm. In some embodiments, the thickness of the area where the first current collector 23 is connected to the first solder mark 25 along the first direction X can be 1mm-3mm.

[0231] Among them, Figure 6 In the first current collector 23, the thickness of the area where the first current collector 23 is connected to the first solder mark 25 is T2. Correspondingly, the thickness of the area where the first current collector 23 is connected to the first solder mark 25 in the first direction X is the sum of the minimum distance between the area of ​​the first current collector 23 facing the main body 241 in the first direction X and the area corresponding to the first solder mark 25 and the thickness of the portion of the first solder mark 25 extending into the first current collector 23 in the first direction X.

[0232] For example, the thickness T2 of the area where the first current collector 23 is connected to the first solder mark 25 can be any one of the following values ​​or a range between any two: 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, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3mm, 3.1mm, 3.2mm, 3.3mm, 3.4mm, 3.5mm, 3.6mm, 3.7mm, 3.8mm, 3.9mm, 4mm.

[0233] In this embodiment, on the one hand, the thickness of the area where the first current collector 23 is connected to the first solder mark 25 is set to be greater than or equal to 0.3 mm, so as to reduce the risk of the first current collector 23 being burned or damaged after being soldered through, and to increase the depth of the molten pool of the first solder mark 25 in the first current collector 23, thereby improving the welding reliability between the first tab 242 and the first current collector 23, and also improving the structural strength of the first current collector 23. On the other hand, the thickness of the area where the first current collector 23 is connected to the first solder mark 25 is set to be less than or equal to 4 mm, so as to alleviate the phenomenon that the first current collector 23 occupies too much space between the first tab 242 and the main body 241, which is conducive to optimizing the space occupied by the first tab 242 and the first current collector 23 as a whole in the first direction X, and is conducive to reducing the difficulty of bending multiple sub-tabs 2421 toward the second direction Y and extending to the side of the first current collector 23 away from the main body 241.

[0234] According to some embodiments of this application, in conjunction with Figure 6 , Figure 8 and Figure 9 As shown, the extension dimension of the sub-electrode 2421 from one end connected to the first electrode segment 2411a to the end away from the first electrode segment 2411a is 5mm-40mm. In some embodiments, the extension dimension of the sub-electrode 2421 from one end connected to the first electrode segment 2411a to the end away from the first electrode segment 2411a can be 15mm-30mm.

[0235] The extension dimension of the sub-electrode 2421 from one end connected to the first pole segment 2411a to the end away from the first pole segment 2411a is the length dimension of the sub-electrode 2421 along its extension trajectory from one end connected to the first pole segment 2411a to the end away from the first pole segment 2411a.

[0236] It should be noted that if the sub-tab 2421 is unfolded and the thickness direction of the sub-tab 2421 is set to be parallel to the second direction Y (e.g.) Figure 9 As shown), the extension dimension of the sub-electrode 2421 from one end connected to the first pole segment 2411a to the end away from the first pole segment 2411a is the length dimension of the sub-electrode 2421 in the first direction X, that is, the extension dimension of the sub-electrode 2421 from one end connected to the first pole segment 2411a to the end away from the first pole segment 2411a is L2, which satisfies 5mm≤L2≤40mm.

[0237] For example, the extension dimension of the sub-pole tab 2421 from one end connected to the first pole segment 2411a to the end away from the first pole segment 2411a can be any one of the following values ​​or a range between any two: 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 26mm, 27mm, 28mm, 29mm, 30mm, 31mm, 32mm, 33mm, 34mm, 35mm, 36mm, 37mm, 38mm, 39mm, 40mm.

[0238] In this embodiment, on the one hand, the extension dimension of the sub-electrode 2421 from one end connected to the first electrode segment 2411a to the end away from the first electrode segment 2411a is set to be greater than or equal to 5mm. This reduces the difficulty of bending multiple sub-electrode 2421s toward the second direction Y and extending them to the side of the first current collector 23 away from the main body 241. It also reduces the difficulty of stacking and welding multiple connection areas 24211 formed by multiple sub-electrode 2421s after bending with the first current collector 23. Furthermore, it helps to increase the area of ​​the connection areas 24211 formed by the sub-electrode 2421s after bending, thereby increasing the area where the sub-electrode 2421s can be stacked and welded with the first current collector 23. On the other hand, because The multiple sub-tabs 2421 of the first tab 242 are not fixed to each other before being welded and assembled with the first current collector 23. This allows the multiple sub-tabs 2421 to have the ability to move and shift relative to each other during the process of smoothing and bending the first tab 242. By setting the extension dimension of the sub-tab 2421 from one end connected to the first electrode segment 2411a to the end away from the first electrode segment 2411a to less than or equal to 40mm, the phenomenon of redundancy or local bulging of the sub-tab 2421 after bending can be effectively alleviated. This is to optimize the space occupied by the first tab 242 as a whole in the first direction X, which is conducive to improving the internal space utilization of the battery cell 20 and thus improving the energy density of the battery cell 20.

[0239] According to some embodiments of this application, refer to Figure 6 Please refer to further details. Figure 12 As shown, Figure 12This is a front view of the first tab 242 of the electrode assembly 24 of the battery cell 20 provided in some embodiments of this application after being welded and assembled with the first current collector 23, in the first direction X. In the projection plane perpendicular to the first direction X, the orthographic projection of the first solder mark 25 is a strip structure extending along a straight trajectory, and the length direction of the orthographic projection of the first solder mark 25 is parallel to the second direction Y, or the angle between the length direction of the orthographic projection of the first solder mark 25 and the second direction Y is less than or equal to 30°. That is, the orthographic projection of the first solder mark 25 in the projection plane perpendicular to the first direction X is a long strip structure extending along the second direction Y or in a direction approximately in the second direction Y, and the length direction of the orthographic projection of the first solder mark 25 in the projection plane perpendicular to the first direction X is parallel or approximately parallel to the stacking direction of the plurality of first electrode segments 2411a and the arrangement direction of the connection positions of the plurality of sub-tabs 2421 and the main body 241.

[0240] For example, in a projection plane perpendicular to the first direction X, if the length direction of the orthographic projection of the first solder mark 25 is parallel to the second direction Y, then the angle between the length direction of the orthographic projection of the first solder mark 25 and the second direction Y is 0°. If the angle between the length direction of the orthographic projection of the first solder mark 25 and the second direction Y is less than or equal to 30°, then the angle between the length direction of the orthographic projection of the first solder mark 25 and the second direction Y can be 0.1°, 0.2°, 0.3°, etc. The value of any one of the following: 0.4°, 0.5°, 1°, 1.5°, 2°, 2.5°, 3°, 3.5°, 4°, 4.5°, 5°, 6°, 7°, 8°, 9°, 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24°, 25°, 26°, 27°, 28°, 29°, 30°, or a range between any two.

[0241] Optionally, the first weld mark 25 formed by welding each first tab 242 to the first current collector 23 can be one or more.

[0242] It should be noted that in other embodiments, the orthographic projection of the first solder mark 25 in the projection plane perpendicular to the first direction X can also be a rectangular, circular, elliptical or other structure.

[0243] In this embodiment, since the multiple first electrode segments 2411a are stacked along the second direction Y, and the sub-electrode tabs 2421 are bent towards the second direction Y, the connection positions of the multiple sub-electrode tabs 2421 of the first electrode tab 242 and the corresponding first electrode segments 2411a are arranged along the second direction Y. This ensures that the multiple sub-electrode tabs 2421 of the first electrode tab 242 are arranged along the second direction Y before being smoothed and bent. Therefore, after the multiple sub-electrode tabs 2421 are bent towards the second direction Y, the first solder mark 25 is placed perpendicular to the first direction Y. The orthographic projection of the first solder mark 25 into the projection plane of X is set as a strip structure extending along a straight trajectory. The length direction of the orthographic projection of the first solder mark 25 into the projection plane perpendicular to the first direction X is parallel to the second direction Y or the angle between the first solder mark 25 and the second direction Y is less than or equal to 30°. This enables the first solder mark 25 to be connected to more sub-tabs 2421, thereby further improving the current flow effect between the first tab 242 and the first current collector 23, and further improving the connection stability between the first tab 242 and the first current collector 23.

[0244] In some embodiments, see Figure 12 As shown, there are multiple first solder marks 25 on the first tab 242. These multiple first solder marks 25 are arranged at intervals along the third direction Z, and the first direction X, the second direction Y, and the third direction Z are perpendicular to each other. That is, in the projection plane perpendicular to the first direction X, the orthographic projections of the multiple first solder marks 25 are spaced apart along their width direction.

[0245] In this embodiment, by providing a plurality of first solder marks 25 on the first tab 242, and the plurality of first solder marks 25 being arranged at intervals along the third direction Z, the orthographic projection of the plurality of first solder marks 25 in the projection plane perpendicular to the first direction X is a structure arranged at intervals along its width direction. The battery cell 20 with this structure can further improve the welding reliability and welding area between the first tab 242 and the first current collector 23, thereby further improving the current flow effect between the first tab 242 and the first current collector 23, and further improving the first tab 242. 2. The connection stability between the sub-tab 2421 and the first current collector 23 is improved. On the other hand, even if there is a poor connection between the sub-tab 2421 and some of the first solder marks 25, the provision of multiple first solder marks 25 enables the sub-tab 2421 to maintain connection with the first current collector 23 through the remaining first solder marks 25. This improves the fault tolerance rate of the welding assembly between the sub-tab 2421 and the first current collector 23 and improves the electrical connection stability between the sub-tab 2421 and the first current collector 23, thereby reducing the risk of connection failure between the sub-tab 2421 and the first current collector 23.

[0246] In some embodiments, please continue to see Figure 12 As shown, along the third direction Z, the minimum distance between two adjacent first solder marks 25 is 1mm-10mm. In some embodiments, the minimum distance between two adjacent first solder marks 25 along the third direction Z can be 3mm-5mm.

[0247] Among them, Figure 12 In the middle, along the third direction Z, the minimum distance between two adjacent first solder marks 25 is D. That is, the minimum width dimension of the gap between two adjacent first solder marks 25 in the third direction Z is D, i.e., 1mm≤D≤10mm.

[0248] For example, along the third direction Z, the minimum distance D between two adjacent first solder marks 25 can be any one of the following values ​​or a range between any two: 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm, etc.

[0249] In this embodiment, on the one hand, the minimum spacing between two adjacent first solder marks 25 in the third direction Z is set to be greater than or equal to 1 mm. This reduces the forming difficulty of multiple first solder marks 25 arranged at intervals along the third direction Z, thereby reducing the welding difficulty between the first tab 242 and the first current collector 23. It also reduces the influence of the molten pool between two adjacent first solder marks 25, which is beneficial to improving the connection quality between each first solder mark 25 and the first tab 242. On the other hand, the minimum spacing between two adjacent first solder marks 25 in the third direction Z is set to be less than or equal to 10 mm. This alleviates the phenomenon that the number of first solder marks 25 provided on the first tab 242 is limited due to the excessive spacing between two adjacent first solder marks 25. This facilitates the welding of more first solder marks 25 between the first tab 242 and the first current collector 23, which is beneficial to improving the connection stability and current flow effect between the first tab 242 and the first current collector 23.

[0250] In some embodiments, combined with Figure 9 and Figure 12 As shown, each sub-pole tab 2421 is fixedly connected to at least two first solder pads 25.

[0251] Each sub-tab 2421 is fixedly connected to at least two first solder pads 25, that is, each sub-tab 2421 is passed through by at least two first solder pads 25, so that at least two solder pad areas 24212 are formed on each sub-tab 2421.

[0252] In this embodiment, by fixing each sub-tab 2421 to at least two first solder marks 25, each sub-tab 2421 is a structure through which at least two first solder marks 25 pass. On the one hand, this can increase the flow area and flow path between each sub-tab 2421 and the first current collector 23. On the other hand, it can ensure that even if the sub-tab 2421 fails to connect with one or some of the first solder marks 25, it can still be electrically connected to the first current collector 23 through other first solder marks 25, which is beneficial to improving the electrical connection stability between the sub-tab 2421 and the first current collector 23.

[0253] In some embodiments, see Figure 12 As shown, in the projection plane perpendicular to the first direction X, the width of the orthographic projection of the first solder mark 25 on the third direction Z is 0.5mm-5mm, and the first direction X, the second direction Y and the third direction Z are perpendicular to each other.

[0254] Among them, Figure 12 In the first solder mark 25, the width of the orthographic projection of the first solder mark 25 in the projection plane perpendicular to the first direction X onto the third direction Z is W, that is, 0.5mm≤W≤5mm, and in some embodiments, 1mm≤W≤2mm.

[0255] For example, the width W of the orthographic projection of the first solder mark 25 in the projection plane perpendicular to the first direction X onto the third direction Z can be any one of the following values ​​or a range between any two: 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, 2.2mm, 2.5mm, 2.8mm, 3mm, 3.2mm, 3.5mm, 3.8mm, 4mm, 4.2mm, 4.5mm, 4.8mm, 5mm.

[0256] In this embodiment, on the one hand, the width of the orthographic projection of the first solder mark 25 in the projection plane perpendicular to the first direction X onto the third direction Z is set to be greater than or equal to 0.5 mm, so as to increase the connection area between the first solder mark 25 and the sub-tab 2421, thereby improving the current flow effect between the first tab 242 and the first current collector 23, and also improving the connection stability between the first tab 242 and the first current collector 23. On the other hand, the width of the orthographic projection of the first solder mark 25 in the projection plane perpendicular to the first direction X onto the third direction Z is set to be less than or equal to 5 mm, so as to alleviate the phenomenon that the weld pool width of the first solder mark 25 formed by the welding of the first current collector 23 and the first tab 242 is too large, which helps to reduce the power required for welding and assembling the first current collector 23 and the first tab 242, and can reduce the area of ​​the sub-tab 2421 that is passed through by the first solder mark 25, thereby reducing the risk of damage to the sub-tab 2421.

[0257] According to some embodiments of this application, see Figure 9 As shown, the area through which the sub-electrode 2421 is penetrated by the first solder mark 25 forms a solder mark area 24212. The surface area of ​​the sub-electrode 2421 on one side in its thickness direction is S1, and the sum of the areas of all solder marks 24212 on the same sub-electrode 2421 is S2, satisfying 0.0075≤S2 / S1≤0.1.

[0258] Wherein, S1 is the area of ​​one side of the surface of a single sub-electrode 2421 in its thickness direction after it is unfolded, and the solder area 24212 is the area through which the sub-electrode 2421 is passed by the corresponding first solder part 25, and is also the area where the sub-electrode 2421 is connected to the corresponding first solder part 25, and is also the area where the sub-electrode 2421 and the first current collector 23 are welded together to form the first solder part 25. Correspondingly, if only one solder area 24212 is formed on the sub-electrode 2421, then S2 is the area of ​​the solder area 24212. If multiple solder areas 24212 are formed on the sub-electrode 2421, then S2 is the sum of the areas of the multiple solder areas 24212.

[0259] If the sub-tie 2421 is unfolded and the thickness direction of the sub-tie 2421 is set to be parallel to the second direction Y (e.g.) Figure 9 As shown), S1 is the area of ​​the orthographic projection of the sub-taper 2421 in the projection plane perpendicular to the second direction Y, and S2 is the sum of the areas of the orthographic projections of all the portions of the first solder marks 25 located on the sub-taper 2421 in the projection plane perpendicular to the second direction Y. Correspondingly, S2 / S1 refers to the ratio of the area of ​​the orthographic projection of all the portions of the first solder marks 25 located on the sub-taper 2421 to the area of ​​the orthographic projection of the corresponding sub-taper 2421 in the projection plane perpendicular to the second direction Y.

[0260] For example, S2 / S1 can be any one of the following point values ​​or a range of values ​​between any two: 0.0075, 0.008, 0.0085, 0.009, 0.0095, 0.01, 0.011, 0.012, 0.013, 0.014, 0.015, 0.016, 0.017, 0.018, 0.019, 0.02, 0.025, 0.03, 0.035, 0.04, 0.045, 0.05, 0.055, 0.06, 0.065, 0.07, 0.075, 0.08, 0.085, 0.09, 0.095, 0.1.

[0261] In this embodiment, on the one hand, the sum of the areas of all solder areas 24212 is set to be greater than or equal to 0.0075 times the surface area of ​​the corresponding sub-tab 2421 on one side in the thickness direction, so as to increase the welding area between the individual sub-tab 2421 and the first current collector 23, thereby improving the current flow effect between the individual sub-tab 2421 and the first current collector 23, and also improving the connection stability between the individual sub-tab 2421 and the first current collector 23. On the other hand, the sum of the areas of all solder areas 24212 is set to be less than or equal to 0.1 times the surface area of ​​the corresponding sub-tab 2421 on one side in the thickness direction, so as to alleviate the phenomenon that the area of ​​the sub-tab 2421 passed by the first solder part 25 is too large, which helps to reduce the welding difficulty between the individual sub-tab 2421 and the first current collector 23, and also helps to reduce the power required for welding and assembling the first current collector 23 and the first tab 242.

[0262] According to some embodiments of this application, in conjunction with Figure 6 , Figure 7 and Figure 8 As shown, the sub-electrode 2421 has a connection end 24213 connected to the first pole segment 2411a. In the projection plane perpendicular to the first direction X, at least a portion of the orthographic projection of the connection end 24213 of the sub-electrode 2421 is located within the orthographic projection of the first current collector 23, and the sub-electrode 2421 with the orthographic projection of the connection end 24213 located within the orthographic projection of the first current collector 23 is bent around the first current collector 23.

[0263] Among them, the connection end 24213 of the sub-electrode 2421 is the end where the sub-electrode 2421 is connected to the corresponding first pole segment 2411a.

[0264] In a projection plane perpendicular to the first direction X, the orthographic projection of the connection end 24213 of at least a portion of the sub-taper 2421 is located within the orthographic projection of the first current collector 23, and the sub-taper 2421 whose orthographic projection of the connection end 24213 is located within the orthographic projection of the first current collector 23 is bent around the first current collector 23. That is, at least a portion of the multiple sub-taper 2421 is a structure that extends from between the first current collector 23 and the main body 241 and bends around the first current collector 23 on one side in the second direction Y before extending to the side of the first current collector 23 away from the main body 241, such that at least a portion of the multiple sub-taper 2421 is a structure located between the first current collector 23 and the main body 241 in the first direction X.

[0265] Optionally, only some of the sub-tabs 2421 may have their connection ends 24213 located between the first current collector 23 and the main body 241, or all of the sub-tabs 2421 may have their connection ends 24213 located between the first current collector 23 and the main body 241. For example, in... Figure 6 In the middle, the connection end 24213 of a portion of the sub-taper 2421 is located between the first current collector 23 and the main body 241, and the orthographic projection of the connection end 24213 of another portion of the sub-taper 2421 in the projection plane perpendicular to the first direction X does not overlap with the orthographic projection of the first current collector 23 in the projection plane perpendicular to the first direction X.

[0266] In this embodiment, by setting the orthographic projection of at least a portion of the connecting end 24213 of the sub-tab 2421 in a projection plane perpendicular to the first direction X to a structure located within the orthographic projection of the first current collector 23 in a projection plane perpendicular to the first direction X, a portion of the sub-tab 2421 is positioned between the first current collector 23 and the main body 241. This makes the sub-tab 2421 a structure that starts from the side of the first current collector 23 facing the main body 241, bends around the first current collector 23, and extends to the side of the first current collector 23 away from the main body 241. A battery cell 20 employing this structure... On the one hand, it can achieve the function of separating at least part of the tab 2421 between the first current collector 23 and the main body 241, so as to reduce the risk of the main body 241 being burned or damaged after the first current collector 23 is welded through. On the other hand, it can achieve the sharing of part of the space between the first current collector 23 and the first tab 242 in the first direction X, and also achieve the sharing of part of the space between the first current collector 23 and the first tab 242 in the second direction Y, thereby optimizing the overall space occupied by the first current collector 23 and the first tab 242, improving the internal space utilization rate of the battery cell 20, and thus improving the energy density of the battery cell 20.

[0267] In an embodiment where at least a portion of the connection end 24213 of the sub-electrode 2421 is projected onto a projection plane perpendicular to the first direction X within the projection of the first current collector 23, combined with Figure 6 and Figure 8 As shown, along the first direction X, the portion of the sub-electrode 2421 located between the first current collector 23 and the main body 241 gradually moves away from the main body 241 from the end connected to the first pole segment 2411a to the end away from the first pole segment 2411a. In other words, along the first direction X, the distance between the portion of the sub-electrode 2421 located between the first current collector 23 and the main body 241 and the main body 241 gradually increases from the end connected to the first pole segment 2411a to the end away from the first pole segment 2411a.

[0268] It should be noted that, along the first direction X, the portion of the sub-electrode 2421 located between the first current collector 23 and the main body 241 gradually moves away from the main body 241 from the end connected to the first pole segment 2411a to the end away from the first pole segment 2411a. Correspondingly, the portion of the sub-electrode 2421 located between the first current collector 23 and the main body 241 from the end connected to the first pole segment 2411a to the end away from the first pole segment 2411a can be a structure that is inclined and gradually moves away from the main body 241 as a whole (the extension direction is set at an acute angle to the first direction X), or it can be a structure that is partially inclined and gradually moves away from the main body 241 and partially extends along the first direction X, or it can be a structure that is partially inclined and gradually moves away from the main body 241 and partially extends along the second direction Y, or it can be a structure that is partially inclined and gradually moves away from the main body 241, partially extends along the second direction Y and partially extends along the first direction X.

[0269] In this embodiment, since the first electrode tab 242 is bent toward the second direction Y and the multiple sub-electrode tabs 2421 of the first electrode tab 242 are not fixedly connected or pre-welded before being stacked and welded to the first current collector 23, the multiple sub-electrode tabs 2421 of the first electrode tab 242 are structures that can be smoothed and bent before being welded and assembled with the first current collector 23. Thus, the portion of the sub-electrode tab 2421 located between the first current collector 23 and the main body 241 is configured to extend from one end connected to the first electrode segment 2411a to the end away from the first electrode segment 2411a. One end of 11a gradually moves away from the structure of the main body 241 to reduce the occurrence of local bulging or swelling of the part of the sub-tab 2421 located between the first current collector 23 and the main body 241 due to stress. This reduces the risk of cracking or breakage of the part of the sub-tab 2421 located between the first current collector 23 and the main body 241 during assembly or use. It also saves the space occupied by the parts of multiple sub-tabs 2421 located between the first current collector 23 and the main body 241 in the first direction X, thereby increasing the energy density of the battery cell 20.

[0270] Of course, the structure of the battery cell 20 is not limited to this; the battery cell 20 can also have other structures. Please refer to some embodiments of this application. Figure 13 As shown, Figure 13 This is a partial cross-sectional view of the electrode assembly 24 and the first current collector 23 of the battery cell 20 provided in some embodiments of this application after being assembled together. The sub-tab 2421 has a connection end 24213 connected to the first electrode segment 2411a. In the projection plane perpendicular to the first direction X, the orthographic projection of the first current collector 23 does not overlap with the orthographic projection of the connection ends 24213 of all sub-tabs 2421. That is, the projection of the connection ends 24213 of the sub-tabs 2421 in the first direction X does not fall into the first current collector 23.

[0271] In this configuration, all the sub-taps 2421 in the first electrode tab 242 are not located between the first current collector 23 and the main body 241, so that the sub-taps 2421 do not extend to the portion between the first current collector 23 and the main body 241, so that all the sub-taps 2421 are structures that extend from one side of the first current collector 23 in the second direction Y and bend to the side of the first current collector 23 away from the main body 241.

[0272] It should be noted that in this embodiment, the first current collection member 23 can be a structure that directly abuts against the main body 241, or it can be a structure that indirectly abuts against the main body 241 through other components, such as the heat insulation member 30 and / or the support member 31.

[0273] In this embodiment, by setting the orthographic projection of the connection ends 24213 of all the sub-tabs 2421 in a projection plane perpendicular to the first direction X to a structure that does not overlap with the orthographic projection of the first current collector 23 in a projection plane perpendicular to the first direction X, the first current collector 23 is positioned between the sub-tabs 2421 and the main body 241, and the sub-tabs 2421 are designed to start from one side of the first current collector 23 in the second direction Y, bend around the first current collector 23, and extend to the side of the first current collector 23 away from the main body 241. A battery cell 20 with this structure... The surface can reduce the difficulty of smoothing and bending the sub-tab 2421, and can reduce the difficulty of stacking and welding the multiple sub-tabs 2421 of the first tab 242 with the first current collector 23. On the other hand, it can realize that the first current collector 23 and the first tab 242 share part of the space in the first direction X, and can further optimize the size of the first current collector 23 and the main body 241 in the first direction X, thereby saving the space occupied by the first tab 242 and the first current collector 23 as a whole in the first direction X, so as to improve the internal space utilization of the battery cell 20, and thus improve the energy density of the battery cell 20.

[0274] According to some embodiments of this application, see Figure 4 , Figure 5 and Figure 6 as well as Figure 13 As shown, the battery cell 20 may also include a heat insulation member 30, at least a portion of which is disposed between the first current collector 23 and the main body 241 in the first direction X, and at least a portion of the orthographic projection of the first solder mark 25 is located within the orthographic projection of the heat insulation member 30 in a projection plane perpendicular to the first direction X.

[0275] The heat insulation component 30 is at least partially located between the first current collector 23 and the main body 241, such that the first weld mark 25 formed by welding the first tab 242 and the first current collector 23 is located on the side of the heat insulation component 30 away from the main body 241, so as to play a heat insulation role between the first current collector 23 and the main body 241, thereby reducing the risk of the first tab 242 and the first current collector 23 burning or damaging the main body 241 during welding assembly. The connection structure of the heat insulation component 30 between the first current collector 23 and the main body 241 can be various. The heat insulation component 30 can be a structure connected to the surface of the first current collector 23 facing the main body 241, or it can be a structure connected to the end face of the main body 241 facing the first current collector 23.

[0276] In the projection plane perpendicular to the first direction X, at least a portion of the orthographic projection of the first solder mark 25 is located within the orthographic projection of the heat insulation member 30. That is, the heat insulation member 30 is a structure that covers at least a portion of the first solder mark 25 in the first direction X. It can be that the heat insulation member 30 only covers a portion of the first solder mark 25, or it can be that the heat insulation member 30 covers the entire first solder mark 25.

[0277] In some embodiments, the thermal conductivity of the material of the heat insulation component 30 is 0.01 W / m·K - 1 W / m·K, and the melting point of the material of the heat insulation component 30 is greater than or equal to 250°C.

[0278] As an example, the material of the insulation element 30 may include polyimide or polytetrafluoroethylene, etc.

[0279] In this embodiment, by setting at least a portion of the heat insulation member 30 in the first direction X as a structure located between the first current collector 23 and the main body 241, and setting at least a portion of the orthographic projection of the first solder mark 25 in a projection plane perpendicular to the first direction X as a structure located within the orthographic projection of the heat insulation member 30 in a projection plane perpendicular to the first direction X, the first solder mark 25 is located on the side of the heat insulation member 30 away from the main body 241 in the first direction X. This allows the heat insulation member 30 to play a heat insulation role between the first solder mark 25 and the main body 241, thereby reducing the phenomenon of the first current collector 23 and the first tab 242 burning the main body 241 and other components during the welding connection and formation of the first solder mark 25, thus improving the assembly quality of the battery cell 20.

[0280] In some embodiments, see Figure 6 and Figure 13 As shown, in the projection plane perpendicular to the first direction X, the orthographic projection of the first solder mark 25 is entirely located within the orthographic projection of the heat insulation member 30. In other words, the heat insulation member 30 covers the entire first solder mark 25 in the first direction X.

[0281] In this embodiment, by setting the entire orthographic projection of the first solder mark 25 in the projection plane perpendicular to the first direction X to be located within the orthographic projection of the heat insulation member 30 in the projection plane perpendicular to the first direction X, the heat insulation effect of the heat insulation member 30 between the first solder mark 25 and the main body 241 is further improved. This further reduces the phenomenon of the first current collector 23 and the first tab 242 burning the main body 241 and other components during the welding connection and formation of the first solder mark 25, thereby further improving the assembly quality of the battery cell 20.

[0282] In some embodiments, the heat insulation member 30 is made of an insulating material. That is, the heat insulation member 30 can not only provide heat insulation between the first current collector 23 and the main body 241, but also provide insulation between the first current collector 23 and the main body 241.

[0283] In this embodiment, the orthographic projection of the first current collector 23 is located within the orthographic projection of the heat insulation member 30 in the projection plane perpendicular to the first direction X, so as to improve the insulation effect of the heat insulation member 30 in isolating the first current collector 23 and the main body 241. Of course, in other embodiments, the orthographic projection of the first current collector 23 may also be located only partially within the orthographic projection of the heat insulation member 30 in the projection plane perpendicular to the first direction X.

[0284] In this embodiment, by setting the material of the heat insulation component 30 to an insulating material, the heat insulation component 30 can also play an insulating role between the first current collector 23 and the main body 241, thereby reducing the risk of short circuit between the first current collector 23 and the main body 241 during use and improving the reliability of the battery cell 20.

[0285] In some embodiments, see Figure 6 as well as Figure 13 As shown, the heat insulation member 30 is connected to the surface of the first current collector 23 facing the main body 241.

[0286] For example, the heat insulation member 30 is bonded to the surface of the first current collector 23 facing the main body 241. For instance, the heat insulation member 30 can be bonded to the surface of the first current collector 23 facing the main body 241 by adhesive or double-sided adhesive. Of course, in other embodiments, the heat insulation member 30 can also be a structure that is snapped onto the first current collector 23.

[0287] In this embodiment, by setting the heat insulation component 30 as a structure connected to the surface of the first current collector 23 facing the main body 241, on the one hand, the heat insulation component 30 can be assembled together with the first current collector 23 between the first electrode 242 and the main body 241, which helps to reduce the difficulty of setting the heat insulation component 30 between the first current collector 23 and the main body 241 and optimizes the production cycle. On the other hand, it can improve the stability and reliability of the heat insulation component 30 between the first current collector 23 and the main body 241, which helps to reduce the risk of the heat insulation component 30 falling off between the first current collector 23 and the main body 241 during the welding process between the first current collector 23 and the first electrode 242.

[0288] According to some embodiments of this application, please continue to refer to Figure 6 as well as Figure 13As shown, the battery cell 20 may also include a support member 31, which is supported between the first current collector 23 and the main body 241 along the first direction X, and at least a portion of the orthographic projection of the first solder mark 25 is located within the orthographic projection of the support member 31 in a projection plane perpendicular to the first direction X.

[0289] The support member 31 serves to support the first current collector 23 and the main body 241, so that during the welding and assembly of the first electrode 242 and the first current collector 23, the first current collector 23 can act on the main body 241 through the support member 31 to stabilize the first current collector 23. Optionally, the support member 31 can be made of various materials, such as rubber, plastic or ceramic.

[0290] It should be noted that the support member 31 and the first current collecting member 23 can be in direct contact or indirectly contacted through other components. In other words, the support member 31 can directly support the first current collecting member 23 or indirectly support it through other components. Similarly, the support member 31 and the main body 241 can be in direct contact or indirectly contacted through other components.

[0291] For example, in Figure 6 In the illustrated embodiment, at least a portion of the sub-taper 2421's connection end 24213 is located between the first current collector 23 and the main body 241, such that at least a portion of the sub-taper 2421 is located between the first current collector 23 and the main body 241. Correspondingly, the support member 31 is a structure that abuts against the portion of the sub-taper 2421 located between the first current collector 23 and the main body 241. Figure 13 In the illustrated embodiment, the connection ends 24213 of all the sub-tabs 2421 are not located between the first current collector 23 and the main body 241. Correspondingly, the support member 31 is a structure that directly abuts against the main body 241.

[0292] As an example, in an embodiment where the battery cell 20 also includes a heat insulation element 30, at least a portion of the heat insulation element 30 is disposed between the support member 31 and the first current collector 23, such that the support member 31 is a structure that indirectly abuts against the first current collector 23 through the heat insulation element 30. It should be noted that in this embodiment, the heat insulation element 30 can be a structure connected to the first current collector 23 or a structure connected to the support member 31.

[0293] In this embodiment, by providing a support member 31 between the first current collector 23 and the main body 241, and by ensuring that at least a portion of the orthographic projection of the first solder mark 25 in a projection plane perpendicular to the first direction X is located within the orthographic projection of the support member 31 in a projection plane perpendicular to the first direction X, the support member 31 can provide support and stability to the area of ​​the first current collector 23 used for welding with the first tab 242. This reduces the welding gap between the first tab 242 and the first current collector 23 and reduces the shaking phenomenon of the first current collector 23 during welding assembly, thereby reducing the risk of incomplete welding between the first tab 242 and the first current collector 23 and improving the welding quality of the first tab 242 and the first current collector 23.

[0294] According to some embodiments of this application, see Figure 3 , Figure 4 and Figure 5 As shown, the first electrode terminal 22 is disposed on the first wall 21a, and the first current collector 23 is disposed between the main body 241 and the first wall 21a in the first direction X. The first current collector 23 and the first electrode terminal 22 are welded together to form the second solder mark 26.

[0295] The first electrode terminal 22 is disposed on the first wall 21a, that is, the first electrode terminal 22 is disposed on the wall of the outer casing 21 on the side of the main body 241 where the first electrode tab 242 is disposed along the first direction X, so that the first electrode tab 242 and the first electrode terminal 22 are both located on the same side of the main body 241 in the first direction X.

[0296] The first current-collecting member 23 is disposed between the main body 241 and the first wall 21a in the first direction X. That is, the first wall 21a, the first current-collecting member 23 and the main body 241 are arranged in sequence in the first direction X.

[0297] As an example, the second solder mark 26 is a solder mark structure formed by laser welding of the first current collector 23 and the first electrode terminal 22.

[0298] It should be noted that in the embodiment where the first electrode terminal 22 is disposed on the first wall 21a, the welding structure between the first electrode terminal 22 and the first current collector 23 can be various. It can be a structure in which the first electrode terminal 22 and the first current collector 23 are welded together from the side of the first electrode terminal 22 away from the first current collector 23, or it can be a structure in which the first electrode terminal 22 and the first current collector 23 are welded together from the side of the first current collector 23 away from the first electrode terminal 22.

[0299] In this embodiment, by setting the first electrode terminal 22 on the first wall 21a, the first tab 242, the first current collector 23 and the first electrode terminal 22 are all located on the side of the main body 241 facing the first wall 21a in the first direction X. This helps to reduce the difficulty of welding and assembly between the first current collector 23 and the first tab 242 and between the first current collector 23 and the first electrode terminal 22.

[0300] According to some embodiments of this application, refer to Figure 5 Please refer to further details. Figure 14 As shown, Figure 14 This is a cross-sectional view of the battery cell 20 provided in some embodiments of this application after the first electrode terminal 22 and the first current collector 23 are assembled together. Along the first direction X, the outer surface of the first electrode terminal 22 away from the main body 241 includes a second surface 221, and at least a portion of the second solder mark 26 extends from the second surface 221 into the first current collector 23.

[0301] The second surface 221 is a part of the outer surface of the first electrode terminal 22 that is away from the main body 241, so that the second surface 221 is also a part of the outer surface of the first electrode terminal 22 facing the outer side of the housing 21.

[0302] At least a portion of the second solder mark 26 extends from the second surface 221 into the first current collector 23. That is, in the first direction X, the second solder mark 26 is a structure in which at least a portion extends from the second surface 221 of the outer surface of the first electrode terminal 22 toward the main body 241 and into the first current collector 23, such that the second solder mark 26 is connected to the second surface 221 away from the outer surface of the main body 241 in the first direction X, and such that in the projection plane perpendicular to the first direction X, the orthographic projection of the portion of the second solder mark 26 connected to the first current collector 23 can be located within the orthographic projection of the portion of the second solder mark 26 connected to the first electrode terminal 22. That is, when welding and assembling the first electrode terminal 22 and the first current collector 23, the welding equipment is a structure in which the first electrode terminal 22 and the first current collector 23 are welded and assembled from the outside of the housing 21 in the first direction X, such that the second solder mark 26 first passes through the area where the second surface 221 of the first electrode terminal 22 is located and then extends into the first current collector 23.

[0303] As an example, the first electrode terminal 22 has a groove 222 on the side facing away from the main body 241 in the first direction X. The entire groove wall of the groove 222 is a part of the outer surface of the first electrode terminal 22 facing away from the main body 241, and the bottom surface of the groove 222 is the second surface 221. Correspondingly, at least a portion of the second solder mark 26 extends from the bottom surface of the groove 222 through the bottom wall of the groove 222 and then into the first current collector 23. Of course, in other embodiments, the first electrode terminal 22 may also be a structure without the groove 222. Correspondingly, the surface of the first electrode terminal 22 facing away from the main body 241 is the second surface 221, and the second solder mark 26 extends through the entire first electrode terminal 22.

[0304] Optionally, the outer surface of the second solder mark 26 that is away from the main body 241 in the first direction X can be flush with the second surface 221, or it can be a structure in which part of the second solder mark 26 protrudes from the second surface 221.

[0305] In this embodiment, at least a portion of the second solder mark 26 formed by welding the first current collector 23 and the first electrode terminal 22 is configured to extend from the second surface 221 of the first electrode terminal 22 away from the main body 241 into the first current collector 23. This makes the welding assembly between the first current collector 23 and the first electrode terminal 22 a structure in which the first current collector 23 and the first electrode terminal 22 are welded from the side of the first electrode terminal 22 away from the main body 241 in the first direction X. This reduces the welding difficulty between the first current collector 23 and the first electrode terminal 22 because the gap between the first current collector 23 and the main body 241 is too small after the first tab 242 is smoothed and bent and welded to the first current collector 23. This assembly structure also reduces the phenomenon of welding slag and other particles generated by welding the first current collector 23 and the first electrode terminal 22 falling into the casing 21, thereby reducing the risk of internal short circuit in the battery cell 20 during use.

[0306] In some embodiments, see Figure 5 As shown, in the projection plane perpendicular to the first direction X, the orthographic projection of the second solder mark 26 does not overlap with the orthographic projection of the first tab 242. In other words, in the projection plane perpendicular to the first direction X, the orthographic projections of the second solder mark 26 and the first tab 242 do not have any overlapping portions.

[0307] It should be noted that in embodiments where the orthographic projection of the second solder mark 26 in a projection plane perpendicular to the first direction X does not overlap with the orthographic projection of the first tab 242 in a projection plane perpendicular to the first direction X, and the battery cell 20 also includes a heat insulation member 30, the heat insulation member 30 may also be partially disposed between the portion of the first current collector 23 connected to the second solder mark 26 and the main body 241, and at least a portion of the orthographic projection of the second solder mark 26 is located within the orthographic projection of the heat insulation member 30 in the projection plane perpendicular to the first direction X. Correspondingly, a support member 31 may also be disposed between the portion of the first current collector 23 connected to the second solder mark 26 and the main body 241. The support member 31 supports the portion of the first current collector 23 connected to the second solder mark 26 and the main body 241 in the first direction X, and at least a portion of the orthographic projection of the second solder mark 26 is located within the orthographic projection of the support member 31 in the projection plane perpendicular to the first direction X.

[0308] In this embodiment, by setting the orthographic projection of the second solder mark 26 formed by welding the first current collector 23 and the first electrode terminal 22 in a projection plane perpendicular to the first direction X to a structure that does not overlap with the orthographic projection of the first tab 242 in a projection plane perpendicular to the first direction X, the first tab 242 and the second solder mark 26 are staggered in the first direction X, thereby reducing the risk of the second solder mark 26 burning or damaging the first tab 242, and improving the production quality of the battery cell 20.

[0309] In some embodiments, combined with Figure 5 and Figure 14 As shown, the first electrode terminal 22 has a fourth surface 223 facing the main body portion 241 in the first direction X. The fourth surface 223 is disposed opposite to the second surface 221, and the second solder mark portion 26 passes through the fourth surface 223. In the projection plane perpendicular to the first direction X, the orthographic projection of the fourth surface 223 does not overlap with the orthographic projection of the first electrode tab 242.

[0310] The fourth surface 223 is the surface of the first electrode terminal 22 facing the main body 241 in the first direction X and abutting against the first current collector 23. Correspondingly, the fourth surface 223 is disposed opposite to the second surface 221, and the second solder mark 26 passes through the fourth surface 223. That is, the portion of the first electrode terminal 22 located between the second surface 221 and the fourth surface 223 is welded to the first current collector 23 to form at least a portion of the second solder mark 26, and at least a portion of the fourth surface 223 is also welded to the first current collector 23 to form a portion of the second solder mark 26, so that the second solder mark 26 has a structure that passes through the second surface 221 and the fourth surface 223 in the first direction X.

[0311] In the projection plane perpendicular to the first direction X, the orthographic projection of the fourth surface 223 and the orthographic projection of the first tab 242 do not overlap. That is to say, in the projection plane perpendicular to the first direction X, the orthographic projection of the fourth surface 223 and the orthographic projection of the first tab 242 do not have overlapping parts, so that the fourth surface 223 and the first tab 242 are not correspondingly set in the first direction X, and the two are misaligned structures.

[0312] Optionally, in an embodiment where the orthographic projection of the fourth surface 223 in a projection plane perpendicular to the first direction X does not overlap with the orthographic projection of the first electrode tab 242 in a projection plane perpendicular to the first direction X, the first electrode terminal 22 may have a first electrode tab 242 provided on at least one side in the second direction Y, or the first electrode terminal 22 may have a first electrode tab 242 provided on at least one side in the third direction Z.

[0313] It should be noted that in an embodiment where the orthographic projection of the fourth surface 223 in a projection plane perpendicular to the first direction X does not overlap with the orthographic projection of the first tab 242 in a projection plane perpendicular to the first direction X, the thickness of the portion of the second solder mark 26 extending into the first current collector 23 in the first direction X can be 0.25-0.75 of the thickness of the first current collector 23.

[0314] In this embodiment, by setting the orthographic projection of the fourth surface 223 of the first electrode terminal 22 in a projection plane perpendicular to the first direction X to a structure that does not overlap with the orthographic projection of the first tab 242 in a projection plane perpendicular to the first direction X, the interference effect of the first electrode terminal 22 on the first tab 242 can be reduced while realizing the staggered arrangement of the first tab 242 and the second soldering part 26 in the first direction X. This facilitates the layout of the first tab 242, the first current collector 23 and the first electrode terminal 22, and reduces the risk of the first electrode terminal 22 pressing down on the first tab 242 and causing the first tab 242 to be inserted upside down into the main body part 241.

[0315] In some embodiments, see Figure 5 As shown, the first electrode tab 242 is located on at least one side of the first electrode terminal 22 in the third direction Z, and the first direction X, the second direction Y and the third direction Z are perpendicular to each other.

[0316] The first tab 242 is located on at least one side of the first electrode terminal 22 in the third direction Z. That is, the first tab 242 and the first electrode terminal 22 are arranged along the third direction Z. The first tab 242 can be provided on only one side of the first electrode terminal 22 in the third direction Z, or the first tab 242 can be provided on both sides of the first electrode terminal 22 in the third direction Z.

[0317] As an example, in Figure 5 In this embodiment, the main body 241 facing the first wall 21a has only one first electrode tab 242. Correspondingly, the first electrode tab 242 is located on one side of the first electrode terminal 22 in the third direction Z. Of course, in other embodiments, if the main body 241 facing the first wall 21a has multiple first electrode tabs 242, correspondingly, all the first electrode tabs 242 can be located on the same side of the first electrode terminal 22 in the third direction Z, or the first electrode terminal 22 can be provided with first electrode tabs 242 on both sides in the third direction Z.

[0318] In this embodiment, by providing a first tab 242 on at least one side of the first electrode terminal 22 along the third direction Z, the first tab 242 and the first electrode terminal 22 are arranged in a structure along the third direction Z. This enables the arrangement direction of the first tab 242 and the first electrode terminal 22 to be perpendicular to the stacking direction of the plurality of first electrode segments 2411a of the main body 241, which helps to reduce the difficulty of internal layout and assembly of the battery cell 20.

[0319] In some embodiments, refer to Figure 15 and Figure 16 As shown, Figure 15 This is an exploded view of the structure of a battery cell 20 provided in some embodiments of this application. Figure 16 This is a partial cross-sectional view of a battery cell 20 provided in some embodiments of this application, perpendicular to a third direction Z. In a projection plane perpendicular to a first direction X, at least a portion of the orthographic projection of the second solder mark 26 lies within the orthographic projection of the first tab 242, and the first solder mark 25 and the second solder mark 26 are of the same structure.

[0320] Specifically, in the projection plane perpendicular to the first direction X, at least a portion of the orthographic projection of the second solder mark 26 is located within the orthographic projection of the first tab 242. That is, in the projection plane perpendicular to the first direction X, at least a portion of the orthographic projection of the second solder mark 26 overlaps with at least a portion of the first tab 242. Correspondingly, at least a portion of the first tab 242 is disposed in the first direction X corresponding to the second solder mark 26.

[0321] It should be noted that, since the connection areas 24211 of the plurality of sub-tabs 2421 of the first electrode tab 242 are stacked on the side of the first current collector 23 away from the main body 241 and welded to the first current collector 23, if at least a portion of the orthographic projection of the second solder mark 26 formed by the welding connection of the first current collector 23 and the first electrode terminal 22 is located within the orthographic projection of the first electrode tab 242 in a projection plane perpendicular to the first direction X, then the connection areas 24211 of the plurality of sub-tabs 2421 of the first electrode tab 242 are stacked on the first current collector 23 and the first electrode terminal. The structure between the fourth surface 223 of 22, thus, the first solder mark 25 and the second solder mark 26 are the same structure, that is, the first solder mark 25 and the second solder mark 26 are interconnected and form the same solder mark, so that the overall structure formed by the interconnection of the first solder mark 25 and the second solder mark 26 is a structure that passes through the first electrode terminal 22 and the first tab 242 in the first direction X and extends into the first current collector 23. Correspondingly, during the assembly process, it is a structure in which the first electrode terminal 22, the first current collector 23 and the first tab 242 are welded at the same time.

[0322] In this embodiment, at least a portion of the orthographic projection of the second solder mark 26 formed by welding the first current collector 23 and the first electrode terminal 22 into a projection plane perpendicular to the first direction X is configured to be located within the orthographic projection of the first tab 242 into a projection plane perpendicular to the first direction X. This allows the first electrode terminal 22 and the first tab 242 to share a portion of the space in the direction perpendicular to the first direction X, which is beneficial for improving the internal space utilization of the battery cell 20. Furthermore, by setting the first solder mark 25 and the second solder mark 26 to the same structure, such that the first solder mark 25 is the second solder mark 26, and at least a portion of the second solder mark 26 extends from the second surface 221 of the first electrode terminal 22 away from the main body 241 through the first electrode terminal 22 and multiple connection areas 24211 into the first current collector 23, it is possible to achieve a structure in which the first electrode terminal 22, the first current collector 23, and the first tab 242 are simultaneously soldered together. Using this structure, the battery cell 20 can optimize the manufacturing process, improve production efficiency, and reduce the size of the first current collector 23. The range of the heat-affected zone formed by the high temperature of welding can shorten the current path between the first electrode terminal 22 and the first tab 242, thereby improving the current flow effect between the first electrode terminal 22 and the first tab 242. In the process of welding and assembling the first electrode terminal 22, the first current collector 23 and the first tab 242, the first electrode terminal 22 and the first current collector 23 can cooperate to clamp the connection area 24211 of multiple sub-tabs 2421, which helps to reduce the gap between multiple connection areas 24211, thereby reducing the risk of poor welding and improving the welding quality between the first tab 242 and the first current collector 23.

[0323] In some embodiments, see Figure 5 , Figure 14 and Figure 16 As shown, along the first direction X, a groove 222 is provided on the side of the first electrode terminal 22 away from the main body 241. The groove wall surface of the groove 222 is a part of the outer surface of the first electrode terminal 22 away from the main body 241, and the bottom surface of the groove 222 is the second surface 221.

[0324] The groove 222 is a structure that is recessed in the first direction X from the side of the first electrode terminal 22 away from the main body 241 toward the main body 241. Correspondingly, the groove wall surface of the groove 222 is connected to the end face of the first electrode terminal 22 that is furthest from the main body 241 in the first direction X, and both the groove wall surface of the groove 222 and the end face of the first electrode terminal 22 that is furthest from the main body 241 in the first direction X are part of the outer surface of the first electrode terminal 22 that is furthest from the main body 241.

[0325] The bottom surface of the groove 222 is the second surface 221, that is, at least part of the second solder mark 26 is a structure that extends from the bottom surface of the groove 222 toward the main body 241 through the first electrode terminal 22 and into the first current collector 23.

[0326] In this embodiment, by providing a groove 222 on the side of the first electrode terminal 22 away from the main body 241, and the bottom surface of the groove 222 being the second surface 221, the bottom wall of the groove 222 in the first electrode terminal 22 is welded to the first current collector 23 to form a structure of the second solder mark 26. The battery cell 20 with this structure can reduce the thickness of the area of ​​the first electrode terminal 22 used for welding with the first current collector 23, thereby reducing the power required for welding and assembling the first electrode terminal 22 and the first current collector 23, which is beneficial to reducing the welding difficulty between the first electrode terminal 22 and the first current collector 23. On the other hand, it is not necessary to set the first electrode terminal 22 as an overall thinned structure, which is beneficial to reduce the assembly difficulty between the first electrode terminal 22 and the first wall 21a while satisfying the structural strength of the first electrode terminal 22.

[0327] In some embodiments, please continue to see Figure 5 , Figure 14 and Figure 16 As shown, the battery cell 20 may also include a sealing member 32, which is connected to the side of the first electrode terminal 22 away from the main body 241, and the sealing member 32 seals the groove 222.

[0328] The sealing member 32 is connected to the side of the first electrode terminal 22 facing away from the main body 241. That is, the sealing member 32 is a structure connected to the outer surface of the side of the first electrode terminal 22 facing away from the main body 241, so that the sealing member 32 can seal the groove 222, and the second surface 221 is located on the side of the sealing member 32 facing the main body 241 in the first direction X. Correspondingly, the sealing member 32 can be a structure connected to the side surface of the groove 222, or it can be a structure connected to the end face of the first electrode terminal 22 furthest from the main body 241 in the first direction X.

[0329] As an example, see Figure 14 As shown, the sealing member 32 is connected to the side of the groove 222. Part of the sealing member 32 is located inside the groove 222, and the sealing member 32 extends beyond the end face of the first electrode terminal 22 in the first direction X, which is furthest from the main body 241 in the first direction X. Of course, in other embodiments, the sealing member 32 may also be a structure in which the entire sealing member is located inside the groove 222, that is, the sealing member 32 does not extend beyond the end face of the first electrode terminal 22 in the first direction X, which is furthest from the main body 241 in the first direction X.

[0330] Optionally, if the sealing element 32 is made of metal, it can be connected to the first electrode terminal 22 by means of welding, bonding or snap-fitting. If the sealing element 32 is made of non-metallic material, it can be connected to the first electrode terminal 22 by means of bonding or snap-fitting.

[0331] In this embodiment, by connecting a sealing member 32 to the first electrode terminal 22, and the sealing member 32 having a sealing groove 222 structure, the phenomenon of impurities or liquids entering the groove 222 can be reduced during the use of the battery cell 20. Thus, the sealing member 32 can also provide a certain degree of protection for the second solder mark 26, thereby reducing the risk of the second solder mark 26 being worn or corroded and rusted during use.

[0332] According to some embodiments of this application, please refer to Figure 17 , Figure 18 , Figure 19 , Figure 20 and Figure 21 , Figure 17 This is an exploded view of the structure of a battery cell 20 provided in other embodiments of this application. Figure 18 This is a partial cross-sectional view of the battery cell 20 perpendicular to a third direction Z, provided in some other embodiments of this application. Figure 19 This is a partial cross-sectional view of the electrode assembly 24 and the first current collector 23 of the battery cell 20 after they are assembled together, according to some other embodiments of this application. Figure 20 This is a schematic diagram of the structure of the first current collector 23 of the battery cell 20 provided in other embodiments of this application. Figure 21 This is a cross-sectional view of the first current collector 23 of a battery cell 20 provided in other embodiments of this application. The first electrode terminal 22 includes a first connecting portion 224 located within the housing 21. The first connecting portion 224 has a first side surface 2241 and a third surface 2242 facing the main body portion 241 in a first direction X. The first side surface 2241 surrounds and connects to the third surface 2242. The first current collector 23 may include interconnected tab connecting portions 231 and terminal connecting portions 232. Along the first direction X, the connection areas 24211 of multiple sub-tabs 2421 of each first tab 242 are stacked on the side of the tab connecting portion 231 facing away from the main body portion 241 and welded to the tab connecting portion 231 to form a first solder mark 25. The terminal connecting portion 232 extends in the direction facing away from the main body portion 241 and is welded to the first side surface 2241 to form a second solder mark 26.

[0333] The first connecting portion 224 is the part of the first electrode terminal 22 extending into the interior of the housing 21. Correspondingly, the first connecting portion 224 is located on the side of the first wall 21a facing the electrode assembly 24. The first electrode terminal 22 also includes a second connecting portion 225 and a third connecting portion 226. The second connecting portion 225 passes through the first electrode lead-out hole of the first wall 21a along the first direction X, and the third connecting portion 226 is located on the side of the first wall 21a away from the electrode assembly 24, so that the first connecting portion 224 and the third connecting portion 226 are respectively located on both sides of the first wall 21a, and the second connecting portion 225 connects the first connecting portion 224 and the third connecting portion 226. Exemplarily, the first connecting portion 224 and the second connecting portion 225 are integrally formed, and the second connecting portion 225 and the third connecting portion 226 are riveted together. The third connecting portion 226 is used to connect to the busbar component.

[0334] In this embodiment of the application, the first side surface 2241 is the outer peripheral surface of the first connecting portion 224, and the first side surface 2241 is an annular structure extending circumferentially along the first connecting portion 224. The third surface 2242 is the surface of the first connecting portion 224 on the side away from the first wall 21a in the first direction X. Correspondingly, the first side surface 2241 is a structure that surrounds the third surface 2242, and the end of the first side surface 2241 near the main body portion 241 in the first direction X is connected to the third surface 2242.

[0335] The tab connection portion 231 is the portion of the first current collector 23 that is stacked and welded to the first tab 242 in the first direction X, while the terminal connection portion 232 is the portion of the first current collector 23 that is welded to the first electrode terminal 22.

[0336] The terminal connection portion 232 extends away from the main body portion 241 in the first direction X and is welded to the first side surface 2241. That is, in the first direction X, the terminal connection portion 232 is a structure that extends away from the main body portion 241 from one end connected to the tab connection portion 231. Correspondingly, the terminal connection portion 232 extends beyond the surface of the tab connection portion 231 facing the first wall 21a and the third surface 2242 in sequence along the direction of the main body portion 241 pointing to the first wall 21a. A portion of the terminal connection portion 232 is located on the outer periphery of the first connection portion 224 and is welded to the first side surface 2241, such that the thickness direction of the tab connection portion 231 and the thickness direction of the terminal connection portion 232 are perpendicular or approximately perpendicular.

[0337] For example, the terminal connection portion 232 and the tab connection portion 231 are integrally formed. As an example, the terminal connection portion 232 and the tab connection portion 231 can be the same plate formed by bending into an "L" shape. Of course, in other embodiments, the terminal connection portion 232 and the tab connection portion 231 can also be separate structures. Correspondingly, the terminal connection portion 232 can be connected to the tab connection portion 231 by welding or other structures. In this embodiment, the terminal connection portion 232 can be connected to the surface of the tab connection portion 231 facing the first wall 21a, or it can be connected to one end of the tab connection portion 231 in the direction perpendicular to the first direction X.

[0338] In this embodiment, portions of the tab connection 231 and the first tab 242 are stacked and welded together along the first direction X. The terminal connection 232 extends in the first direction X away from the main body 241 and is welded to the first side surface 2241. This allows the tab connection 231 and the terminal connection 232 to be interconnected to form an "L" or "T" shape, and are respectively welded to the first tab 242 and the first connection portion 224 of the first electrode terminal 22. This achieves electrical connection between the first tab 242 and the first electrode terminal 22, while also enabling the terminal connection 232 and the first connection portion 224 to share a common path along the first direction X. Using some space, and because the gap between the first current collector 23 and the main body 241 is too small after the first tab 242 is smoothed and bent and welded to the tab connection 231, the battery cell 20 with this structure can also realize the welding assembly of the terminal connection 232 and the first side 2241 from one side of the first current collector 23, thereby effectively reducing the welding difficulty between the first current collector 23 and the first electrode terminal 22, and can realize the second solder mark 26 is built into the housing 21, so as to reduce the risk of rusting of the second solder mark 26 during use and the risk of leakage of the battery cell 20 at the location of the second solder mark 26.

[0339] In some embodiments, combined with Figure 18 and Figure 21 As shown, the first connecting portion 224 has a fifth surface 2243 facing the first wall 21a in the first direction X. A first side surface 2241 surrounds the fifth surface 2243, and the two ends of the first side surface 2241 in the first direction X are respectively connected to the third surface 2242 and the fifth surface 2243. In the first direction X, the terminal connecting portion 232 does not extend beyond the fifth surface 2243 in the direction from the main body portion 241 toward the first wall 21a.

[0340] The fifth surface 2243 is the surface of the first connecting part 224 facing the first wall 21a. Correspondingly, the first side surface 2241 is arranged around the fifth surface 2243, and the two ends of the first side surface 2241 in the first direction X are respectively connected to the third surface 2242 and the fifth surface 2243.

[0341] In the first direction X, the terminal connection portion 232 does not extend beyond the fifth surface 2243 in the direction from the main body portion 241 to the first wall 21a. That is, in the first direction X, the end of the terminal connection portion 232 away from the main body portion 241 is closer to the main body portion 241 than the fifth surface 2243.

[0342] In this embodiment, by setting the terminal connection portion 232 to a structure in which the direction of the main body portion 241 pointing towards the first wall 21a does not extend beyond the fifth surface 2243 of the first connection portion 224, it is possible to realize that the terminal connection portion 232 and the first connection portion 224 share a portion of space in the first direction X, while also reducing the interference effect of the terminal connection portion 232 on the first wall 21a or other components, thereby reducing the assembly difficulty of the battery cell 20.

[0343] In some embodiments, see Figure 18 , Figure 20 and Figure 21 As shown, the terminal connection portion 232 has a sixth surface 2321 facing away from the first side surface 2241, and at least a portion of the second solder mark portion 26 extends from the sixth surface 2321 into the first connection portion 224.

[0344] The sixth surface 2321 is the surface of the terminal connection portion 232 that is away from the first connection portion 224 in the thickness direction.

[0345] At least a portion of the second solder mark 26 extends from the sixth surface 2321 into the first connecting portion 224. That is, in the thickness direction of the terminal connecting portion 232, the second solder mark 26 is a structure in which at least a portion extends from the sixth surface 2321 on the side of the terminal connecting portion 232 away from the first connecting portion 224 towards and into the first connecting portion 224. This structure ensures that the outer surface of the second solder mark 26 away from the first connecting portion 224 in the thickness direction of the terminal connecting portion 232 is connected to the sixth surface 2321, and that in a projection plane perpendicular to the thickness direction of the terminal connecting portion 232, the second solder mark 26 and the first connecting portion 224 are connected. The orthographic projection of the portion connected to the first connection portion 224 can be a structure located within the orthographic projection of the portion connected to the second solder mark portion 26 and the terminal connection portion 232. That is, when welding and assembling the terminal connection portion 232 and the first connection portion 224, the welding equipment is a structure that welds and assembles the terminal connection portion 232 and the first connection portion 224 from the side of the terminal connection portion 232 away from the first connection portion 224 in the thickness direction of the terminal connection portion 232, so that the second solder mark portion 26 is a structure that first passes through the terminal connection portion 232 and then passes through the first side surface 2241 and extends into the first connection portion 224. That is, the terminal connection portion 232 and the first connection portion 224 are through-welded structures.

[0346] Optionally, the outer surface of the second solder mark 26 that is away from the first connection portion 224 in the thickness direction of the terminal connection portion 232 may be flush with the sixth surface 2321, or it may be that part of the second solder mark 26 protrudes from the sixth surface 2321.

[0347] It should be noted that the structure in which the first connecting portion 224 and the terminal connecting portion 232 are welded together is not limited to this. In other embodiments, the structure in which the first connecting portion 224 and the terminal connecting portion 232 are welded together can also be other structures. For example, the first side surface 2241 can also include a first base surface, on which a protrusion is provided. The outer surface of the protrusion is connected to the first base surface, and the outer surface of the protrusion is a part of the first side surface 2241. The terminal connecting portion 232 and the protrusion are arranged along the first direction X, and the end face of the terminal connecting portion 232 away from the main body portion 241 is welded to the surface of the outer surface of the protrusion facing the terminal connecting portion 232 to form a second solder mark portion 26.

[0348] In this embodiment, by configuring at least a portion of the second solder mark 26 to extend from the sixth surface 2321 of the terminal connection portion 232 into the first connection portion 224, the welding assembly between the terminal connection portion 232 and the first connection portion 224 of the first electrode terminal 22 is configured such that the terminal connection portion 232 and the first connection portion 224 are welded from the side of the terminal connection portion 232 away from the first side surface 2241. On the one hand, this allows the second solder mark 26 to be built into the housing 21, thereby reducing the risk of rusting of the second solder mark 26 during use and the risk of leakage of the battery cell 20 at the location of the second solder mark 26. On the other hand, when welding the terminal connection portion 232 and the first connection portion 224, welding can be performed from any position on the sixth surface 2321, which helps to reduce the welding difficulty between the terminal connection portion 232 and the first connection portion 224 and increases the welding area between the terminal connection portion 232 and the first connection portion 224.

[0349] According to some embodiments of this application, please refer to Figure 22 , Figure 23 , Figure 24 and Figure 25 , Figure 22 Exploded views of the structure of the battery cell 20 provided in some embodiments of this application are also included. Figure 23 This application also provides partial cross-sectional views of the battery cell 20 perpendicular to a third direction Z in some embodiments. Figure 24 This application also provides partial cross-sectional views of the electrode assembly 24 and the first current collector 23 of the battery cell 20 after mutual assembly in some embodiments. Figure 25 This application also provides a schematic diagram of the structure of the first current collector 23 of the battery cell 20 according to some embodiments. The first current collector 23 is located between the main body 241 and the first electrode terminal 22, and the first current collector 23 includes a tab connection portion 231, a bending portion 233, and a terminal connection portion 232 connected in sequence. Along the first direction X, the connection areas 24211 of a plurality of sub-tabs 2421 of each first tab 242 are stacked on the side of the tab connection portion 231 away from the main body 241 and are welded to the tab connection portion 231 to form a first solder mark portion 25, and the terminal connection portion 232 is located on the side of the tab connection portion 231 facing the first electrode terminal 22 and is welded to the first electrode terminal 22 to form a second solder mark portion 26.

[0350] The terminal connection portion 232 is the part of the first current collector 23 located on the side of the first electrode terminal 22 facing the main body portion 241 and welded to the first electrode terminal 22. The tab connection portion 231 is the part of the first current collector 23 and the connection areas 24211 of the plurality of sub-tabs 2421 stacked and welded together along the first direction X to form the first solder mark portion 25. The terminal connection portion 232 and the tab connection portion 231 are stacked along the first direction X. The terminal connection portion 232 is located between the tab connection portion 231 and the first electrode terminal 22. Accordingly, the bending portion 233 is the part of the first current collector 23 that is bent and connects the tab connection portion 231 and the terminal connection portion 232. It should be noted that the first current collector 23 can be bent to form the bending portion 233 after it has been welded and assembled with the first tab 242 and the first electrode terminal 22. That is, the terminal connection portion 232, the bending portion 233 and the tab connection portion 231 are connected in sequence and integrally formed. The terminal connection portion 232, the bending portion 233 and the tab connection portion 231 are formed by bending the same base material.

[0351] It should be noted that, since the connection areas 24211 of the multiple sub-tabs 2421 are stacked on the side of the first current collector 23 away from the main body 241, correspondingly, in the embodiment where the first current collector 23 includes a terminal connection portion 232, a bending portion 233 and a tab connection portion 231 connected in sequence, the connection areas 24211 of the multiple sub-tabs 2421 are stacked between the tab connection portion 231 and the terminal connection portion 232.

[0352] In this embodiment, the first current collector 23 includes a terminal connection portion 232, a bending portion 233, and a tab connection portion 231 connected in sequence. The terminal connection portion 232 is located on the side of the tab connection portion 231 facing the first electrode terminal 22 and is welded to the first electrode terminal 22. The tab connection portion 231 and the first tab 242 are partially stacked and welded together along the first direction X, so that the terminal connection portion 232, the bending portion 233, and the tab connection portion 231 are connected in sequence to form a U-shaped structure. The terminal connection portion 232 and the tab connection portion 231 are arranged along the first direction X and welded to the first electrode terminal 22 and the first tab 242 respectively to realize the electrical connection between the first tab 242 and the first electrode terminal 22. In addition, since the first tab 242 is flattened and bent and connected to the tab connection portion The welding of 231 results in an excessively small gap between the first current collector 23 and the main body 241. Therefore, the battery cell 20 with this structure can first weld the unfolded first current collector 23 to the first tab 242 and the first electrode terminal 22, and then bend the first current collector 23 to form a bent portion 233. After that, the electrode assembly 24 and other components are assembled into the housing 21. This facilitates welding and assembling the terminal connection portion 232 and the first electrode terminal 22 from one side of the first current collector 23, thereby effectively reducing the welding difficulty between the first current collector 23 and the first electrode terminal 22. It also allows the second solder mark portion 26 to be built into the housing 21, reducing the risk of rusting of the second solder mark portion 26 during use and the risk of leakage of the battery cell 20 at the location of the second solder mark portion 26.

[0353] In some embodiments, refer to Figure 24 and Figure 25 Please refer to further details. Figure 26 As shown, Figure 26 The first current collector 23 of the battery cell 20 provided in some embodiments of this application is shown in a partial cross-sectional view perpendicular to the third direction Z. The first current collector 23 is a single-layer foil 23a structure, and the thickness of the bent portion 233 is 0.5mm-2mm.

[0354] Among them, the first current collector 23 is a single-layer foil 23a structure, that is, the first current collector 23 is a structure formed by bending a single layer of metal sheet.

[0355] exist Figure 26In the first current collector 23, the thickness of the bent portion 233 is T3, i.e., 0.5mm ≤ T3 ≤ 2mm. For example, the thickness T3 of the bent portion 233 of the first current collector 23 can be any one of the following values, or a range between any two: 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, or 2mm.

[0356] For example, the material of the first current collector 23 may be aluminum, aluminum alloy or copper, etc.

[0357] In this embodiment, the first current collector 23 is a single-layer foil 23a structure. On the one hand, the thickness of the bent portion 233 of the first current collector 23 is set to be greater than or equal to 0.5 mm to improve the structural strength of the bent portion 233. This helps to alleviate the phenomenon of breakage or cracking of the bent portion 233 during bending or use, thereby improving the stability and service life of the first current collector 23 and reducing the risk of unstable connection or connection failure of the electrode assembly 24 and the first electrode terminal 22 during use. On the other hand, the thickness of the bent portion 233 of the first current collector 23 is set to be less than or equal to 2 mm to reduce the deformation resistance of the bent portion 233. This reduces the difficulty of bending the bent portion 233 of the first current collector 23, so that the first current collector 23 can be bent to form the bent portion 233 after the first tab 242 and the first electrode terminal 22 are welded together.

[0358] In some embodiments, see Figure 25 and Figure 26 As shown, the thickness of the tab connection portion 231 is greater than or equal to the thickness of the bent portion 233. And / or, the thickness of the terminal connection portion 232 is greater than or equal to the thickness of the bent portion 233.

[0359] As an example, in Figure 26 In the first current collector 23 shown, the thickness of the tab connection portion 231 is equal to the thickness of the bending portion 233. Of course, in other embodiments, the thickness of the tab connection portion 231 may also be greater than the thickness of the bending portion 233.

[0360] As an example, in Figure 26 In the first current collector 23 shown, the thickness of the terminal connection portion 232 is equal to the thickness of the bending portion 233. Of course, in other embodiments, the thickness of the terminal connection portion 232 may also be greater than the thickness of the bending portion 233.

[0361] In this embodiment, by setting the thickness of the tab connection portion 231 to be equal to the thickness of the bending portion 233, the tab connection portion 231 and the bending portion 233 are of equal thickness, thereby reducing the difficulty of stamping and cutting the substrate of the first current collector 23 of the single-layer foil 23a structure. By setting the thickness of the tab connection portion 231 to be greater than the thickness of the bending portion 233, the thickness of the area of ​​the first current collector 23 used for welding with the first tab 242 can be increased while reducing the deformation resistance of the bending portion 233. This reduces the difficulty of bending the bending portion 233 of the first current collector 23 and increases the welding penetration of the tab connection portion 231, thereby improving the welding reliability between the tab connection portion 231 and the first tab 242. Similarly, by setting the thickness of the terminal connection portion 232 to be equal to the thickness of the bending portion 233, making the terminal connection portion 232 and the bending portion 233 of equal thickness, the difficulty of stamping and cutting the substrate of the first current collector 23 of the single-layer foil 23a structure can be reduced. By setting the thickness of the terminal connection portion 232 to be greater than the thickness of the bending portion 233, the thickness of the area of ​​the first current collector 23 used for welding with the first electrode terminal 22 can be increased while reducing the deformation resistance of the bending portion 233. This reduces the difficulty of bending the bending portion 233 of the first current collector 23 and increases the welding penetration of the terminal connection portion 232, thereby improving the welding reliability between the terminal connection portion 232 and the first electrode terminal 22.

[0362] Of course, in embodiments where the first current collector 23 includes a tab connection portion 231, a bending portion 233, and a terminal connection portion 232 connected in sequence, the structure of the first current collector 23 is not limited to this. In some embodiments, the first current collector 23 can also have other structures, for example, referring to... Figure 25 Please refer to further details. Figure 27 As shown, Figure 27 The following is a partial cross-sectional view of the bent portion 233 of the first current collector 23 of the battery cell 20 provided in some embodiments of this application in other embodiments. The first current collector 23 may include a plurality of foils 23a, which are stacked and connected, and the thickness of the portion of each foil 23a located at the bent portion 233 is 0.05mm-0.1mm.

[0363] The first current collector 23 includes multiple foils 23a, which are stacked and connected. In other words, the first current collector 23 is a structure formed by stacking and connecting multiple foils 23a and then bending them.

[0364] Optionally, the connection structure between the multiple foils 23a of the first current collector 23 can be various, such as abutment or adhesion. Of course, in some embodiments, the multiple foils 23a of the first current collector 23 can also be interlocked, for example, multiple foils 23a are stacked and then a groove is punched on one side of the multiple foils 23a, so that the foil 23a has a groove on one side and a protrusion on the other side corresponding to the groove. In two adjacent foils 23a, the protrusion of one foil 23a is interlocked with the groove of another foil 23a to realize the interlocking of multiple foils. Of course, in other embodiments, the multiple foils 23a of the first current collector 23 can also be welded to each other, such as by ultrasonic welding.

[0365] exist Figure 27 In this embodiment, the thickness of the portion of a single foil 23a located at the bend 233 is T4, i.e., 0.05mm ≤ T4 ≤ 0.1mm. For example, the thickness T4 of the portion of a single foil 23a located at the bend 233 can be any one of 0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.09mm, or 0.1mm, or a range between any two.

[0366] For example, the number of foils 23a stacked in the first current collector 23 can be two, three, four, five, six, seven, eight or more.

[0367] In this embodiment, the first current collector 23 is a structure formed by stacking and connecting multiple foil sheets 23a, which can reduce the difficulty of bending the bent portion 233 of the first current collector 23 while meeting the welding penetration requirements of the first current collector 23. On the one hand, the thickness of the portion of foil 23a located in the bending portion 233 is set to be greater than or equal to 0.05 mm to improve the structural strength of the portion of foil 23a located in the bending portion 233. This helps to alleviate phenomena such as breakage or cracking of foil 23a during the bending process of the bending portion 233 or during use, thereby improving the stability and service life of the first current collector 23 and reducing the risk of unstable connection or connection failure of electrode assembly 24 and first electrode terminal 22 during use. On the other hand, the thickness of the portion of foil 23a located in the bending portion 233 is set to be less than or equal to 0.1 mm to reduce the deformation resistance of a single foil 23a. This reduces the difficulty of bending the bending portion 233 of the first current collector 23, so that the unfolded first current collector 23 is welded to the first tab 242 and the first electrode terminal 22 before bending the first current collector 23 to form the bending portion 233.

[0368] In some embodiments, see Figure 27As shown, the sum of the thicknesses of the portions of the multiple foils 23a located at the bending portion 233 is 0.5mm-2mm.

[0369] The sum of the thicknesses of the portions of the multiple foils 23a located in the bending portion 233 is also the thickness of the bending portion 233 of the first current collector 23 minus the sum of the gaps between all two adjacent foils 23a within the bending portion 233. If all the foils 23a within the bending portion 233 are tightly fitted together, then the sum of the thicknesses of the portions of the multiple foils 23a located in the bending portion 233 is also the thickness of the bending portion 233 of the first current collector 23.

[0370] exist Figure 27 In this configuration, the sum of the thicknesses of the portions of the plurality of foils 23a located at the bend 233 is T5, i.e., 0.5mm ≤ T5 ≤ 2mm. Correspondingly, the first current collector 23 includes at least five foils 23a stacked together. For example, the sum of the thicknesses T5 of the portions of the plurality of foils 23a located at the bend 233 can be any one of 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, or 2mm, or a range between any two.

[0371] In this embodiment, on the one hand, the sum of the thicknesses of the portions of the multiple foils 23a located in the bending portion 233 is set to be greater than or equal to 0.5 mm to improve the overall structural strength of the bending portion 233. This helps to alleviate phenomena such as breakage or cracking of the bending portion 233 during bending or use, thereby improving the stability and service life of the first current collector 23 and reducing the risk of unstable connection or connection failure of the electrode assembly 24 and the first electrode terminal 22 during use. On the other hand, the sum of the thicknesses of the portions of the multiple foils 23a located in the bending portion 233 is set to be less than or equal to 2 mm to reduce the overall deformation resistance of the bending portion 233. This reduces the difficulty of bending the bending portion 233 of the first current collector 23, so that the first current collector 23 can be bent to form the bending portion 233 after the first tab 242 and the first electrode terminal 22 are welded together.

[0372] In some embodiments, combined with Figure 25 and Figure 27 As shown, the thickness of the portion of foil 23a located at the tab connection portion 231 is greater than or equal to the thickness of the portion of foil 23a located at the bend portion 233. And / or, the thickness of the portion of foil 23a located at the terminal connection portion 232 is greater than or equal to the thickness of the portion of foil 23a located at the bend portion 233.

[0373] As an example, in this embodiment of the application, the thickness of the portion of foil 23a located at the tab connection portion 231 is equal to the thickness of the portion of foil 23a located at the bend portion 233. Of course, in other embodiments, the thickness of the portion of foil 23a located at the tab connection portion 231 may also be greater than the thickness of the portion of foil 23a located at the bend portion 233.

[0374] As an example, in this embodiment of the application, the thickness of the portion of foil 23a located at the terminal connection portion 232 is equal to the thickness of the portion of foil 23a located at the bending portion 233. Of course, in other embodiments, the thickness of the portion of foil 23a located at the terminal connection portion 232 may also be greater than the thickness of the portion of foil 23a located at the bending portion 233.

[0375] In this embodiment, by setting the thickness of the portion of foil 23a located at the tab connection 231 to be equal to the thickness of the portion of foil 23a located at the bend 233, the portions of foil 23a located at the tab connection 231 and the bend 233 are of equal thickness, thereby reducing the difficulty of stamping and cutting individual foils 23a. By setting the thickness of the portion of foil 23a located at the tab connection 231 to be greater than the thickness of the portion of foil 23a located at the bend 233, the deformation resistance of the portion of foil 23a located at the bend 233 is reduced while the thickness of the area of ​​foil 23a used for welding with the first tab 242 is increased. This reduces the difficulty of bending the bend 233 of the first current collector 23 and increases the welding penetration of the tab connection 231, thereby improving the welding reliability between the tab connection 231 and the first tab 242. Similarly, by setting the thickness of the portion of foil 23a located at the terminal connection portion 232 to be equal to the thickness of the portion of foil 23a located at the bending portion 233, the portion of foil 23a located at the terminal connection portion 232 and the portion of foil 23a located at the bending portion 233 are of equal thickness, thereby reducing the difficulty of stamping and cutting individual foils 23a. By setting the thickness of the portion of foil 23a located at the terminal connection portion 232 to be greater than the thickness of the portion of foil 23a located at the bending portion 233, the thickness of the area of ​​foil 23a used for welding with the first electrode terminal 22 can be increased while reducing the deformation resistance of the portion of foil 23a located at the bending portion 233. This reduces the difficulty of bending the bending portion 233 of the first current collector 23 and increases the welding penetration of the terminal connection portion 232, thereby improving the welding reliability between the terminal connection portion 232 and the first electrode terminal 22.

[0376] In some embodiments, see Figure 26As shown, the bent portion 233 is provided with a through hole 2331, which penetrates the bent portion 233 along the thickness direction of the bent portion 233.

[0377] The through hole 2331 is a structure that penetrates the surfaces of both sides of the bent portion 233 in the thickness direction of the bent portion 233. Correspondingly, the number of through holes 2331 provided on the bent portion 233 can be one or more. Similarly, the shape of the cross-section of the through hole 2331 provided on the bent portion 233 can also be various, such as circular, rectangular, elliptical or elongated.

[0378] In this embodiment, by providing a through hole 2331 on the bent portion 233 of the first current collector 23, the deformation resistance of the bent portion 233 can be further reduced, thereby further reducing the difficulty of bending the bent portion 233 of the first current collector 23. This makes it easier to first weld the unfolded first current collector 23 to the first tab 242 and the first electrode terminal 22 before bending the first current collector 23 to form the bent portion 233.

[0379] In some embodiments, refer to Figure 23 and Figure 25 Please refer to further details. Figure 28 , Figure 28 This application also provides a cross-sectional view of the battery cell 20 after the first current collector 23 and the first electrode terminal 22 are assembled together according to some embodiments. Along the first direction X, the terminal connection portion 232 has a seventh surface 2322 facing away from the first electrode terminal 22, and at least a portion of the second solder mark portion 26 extends from the seventh surface 2322 into the first electrode terminal 22.

[0380] The seventh surface 2322 is the surface of the terminal connection portion 232 facing away from the first electrode terminal 22 in the first direction X, and is also the surface of the terminal connection portion 232 facing the tab connection portion 231 in the first direction X.

[0381] Along the first direction X, at least a portion of the second solder mark 26 extends from the seventh surface 2322 into the first electrode terminal 22. That is, in the first direction X, the second solder mark 26 is a structure in which at least a portion of the seventh surface 2322 on the side of the terminal connection portion 232 facing the tab connection portion 231 extends towards and into the first electrode terminal 22, such that the second solder mark 26, in the first direction X, is connected to the seventh surface 2322 away from the outer surface of the first electrode terminal 22, and such that in a direction perpendicular to the first direction X... In the shadow plane, the orthographic projection of the portion where the second solder mark 26 is connected to the first electrode terminal 22 can be a structure located within the orthographic projection of the portion where the second solder mark 26 is connected to the terminal connection portion 232. That is, when welding and assembling the terminal connection portion 232 and the first electrode terminal 22, the welding equipment is a structure that welds and assembles the terminal connection portion 232 and the first electrode terminal 22 from the side of the terminal connection portion 232 away from the first electrode terminal 22 in the first direction X, so that the second solder mark 26 is a structure that first passes through the terminal connection portion 232 and then extends into the first electrode terminal 22.

[0382] Optionally, the outer surface of the second solder mark 26 that is away from the first electrode terminal 22 in the first direction X can be a structure that is flush with the seventh surface 2322, or a structure in which part of the second solder mark 26 protrudes from the seventh surface 2322.

[0383] In this embodiment, by setting at least a portion of the second solder mark 26 to extend from the seventh surface 2322 of the terminal connection portion 232 into the first electrode terminal 22 in the first direction X, the welding assembly between the terminal connection portion 232 and the first electrode terminal 22 is such that the terminal connection portion 232 and the first electrode terminal 22 are welded from the side of the terminal connection portion 232 away from the first electrode terminal 22. This allows the second solder mark 26 to be built into the housing 21, thereby reducing the risk of rusting of the second solder mark 26 during use and the risk of leakage of the battery cell 20 at the location of the second solder mark 26. It also reduces the welding difficulty between the terminal connection portion 232 and the first electrode terminal 22.

[0384] In the embodiment where the first electrode terminal 22 is disposed on the first wall 21a, the battery cell 20 can also have other structures, for example, please refer to Figure 29 As shown, Figure 29The image shows an exploded view of the battery cell 20 provided in some embodiments of this application in other embodiments. The electrode assembly 24 may include a plurality of first tabs 242 of the same polarity. Each of the first tabs 242 is connected to the end of the main body 241 facing the first wall 21a and is spaced apart along the third direction Z. Each of the first tabs 242 is welded to the first current collector 23 to form a first solder mark 25. The first direction X, the second direction Y, and the third direction Z are perpendicular to each other. Along the third direction Z, a portion of the first tabs 242 are located on one side of the first electrode terminal 22, and another portion are located on the other side of the first electrode terminal 22.

[0385] In this embodiment, multiple first tabs 242 are welded to the first current collector 23 to form a first solder mark 25. This can be a structure in which multiple first tabs 242 are welded to the same first current collector 23, or a structure in which each first tab 242 is welded to one first current collector 23. That is, the battery cell 20 is provided with multiple first current collectors 23, and the first current collectors 23 are arranged in a one-to-one correspondence with the first tabs 242. Of course, in embodiments where there are multiple first current collectors 23, it can be a structure in which multiple first current collectors 23 are connected to the same first electrode terminal 22, or a structure in which each first current collector 23 is connected to one first electrode terminal 22. That is, the battery cell 20 is provided with multiple first electrode terminals 22, and the first current collectors 23 are arranged in a one-to-one correspondence with the first electrode terminals 22.

[0386] As an example, in Figure 29 In this structure, multiple first tabs 242 are all welded and assembled with the same first current collector 23 to form multiple first solder marks 25, and the multiple first tabs 242 are welded and connected to different positions of the first current collector 23 to form first solder marks 25.

[0387] Along the third direction Z, a portion of the first tabs 242 are located on one side of the first electrode terminal 22, and another portion of the first tabs 242 are located on the other side of the first electrode terminal 22. That is to say, the first tabs 242 and the first electrode terminal 22 are arranged along the third direction Z, and the first electrode terminal 22 is provided with first tabs 242 on both sides of the third direction Z.

[0388] It should be noted that in other embodiments, the plurality of first tabs 242 are arranged at intervals along the third direction Z, or the plurality of first tabs 242 are all located on the same side of the first electrode terminal 22 in the third direction Z, or at least some of the plurality of first tabs 242 are arranged with the first electrode terminal 22 in the first direction X.

[0389] Optionally, the number of first tabs 242 connected to the end of the main body 241 of the electrode assembly 24 facing the first wall 21a can be two, three, four or more.

[0390] As an example, the electrode assembly 24 includes two first tabs 242 along the third direction Z, with the two first tabs 242 located on both sides of the first electrode terminal 22, and correspondingly, the first electrode terminal 22 is located between the two first tabs 242 in the third direction Z.

[0391] In this embodiment, by setting a portion of the first tabs 242 on one side of the first electrode terminal 22 in the third direction Z, and setting another portion of the first tabs 242 on the other side of the first electrode terminal 22 in the third direction Z, the first electrode terminal 22 is provided with first tabs 242 on both sides in the third direction Z, and the first electrode terminal 22 is positioned between two adjacent first tabs 242 in the third direction Z. The battery cell 20 with this structure can optimize the relationship between the first electrode terminal 22 and the multiple first tabs 242. The arrangement of the tabs 242 allows the first electrode terminal 22 and the first tabs 242 to share space in the first direction X. On the other hand, it enables the multiple first tabs 242 to be structured so that the current is guided from the first electrode terminal 22 on both sides in the third direction Z through the first current collector 23. This shortens the current path between the multiple first tabs 242 and the first electrode terminal 22, which is beneficial to reducing the internal resistance of the battery cell 20 and reducing the current area requirement of the first current collector 23, thereby optimizing the thickness of the first current collector 23.

[0392] According to some embodiments of this application, in conjunction with Figure 6 and Figure 8 And please combine further Figure 30 , Figure 31 , Figure 32 , Figure 33 and Figure 34 As shown, Figure 30 This is a schematic diagram of the structure of a battery cell 20 provided in some other embodiments of this application. Figure 31 This is an exploded view of the structure of a battery cell 20 provided in some other embodiments of this application. Figure 32 This is a cross-sectional view of the battery cell 20 provided in some other embodiments of this application, perpendicular to the second direction Y. Figure 33 This is a partial structural diagram of the battery cell 20 provided in some other embodiments of this application. Figure 34This is a schematic diagram of the structure of the first current collector 23 of the battery cell 20 provided in some other embodiments of this application. The outer casing 21 has a first wall 21a and a second wall 21b that are connected to each other. The first electrode terminal 22 is disposed on the second wall 21b. The thickness direction of the second wall 21b is parallel to the third direction Z. The first direction X, the second direction Y, and the third direction Z are perpendicular to each other. The first current collector 23 may include an electrode tab connection portion 231 and a terminal connection portion 232 that are connected to each other. The electrode tab connection portion 231 is disposed between the main body portion 241 and the first wall 21a in the first direction X. The connection areas 24211 of multiple sub-electrodes 2421 of each first electrode tab 242 are stacked on the side of the electrode tab connection portion 231 away from the main body portion 241 and are welded to the electrode tab connection portion 231 to form a first solder mark portion 25. The terminal connection portion 232 is disposed between the main body portion 241 and the second wall 21b in the third direction Z and is welded to the first electrode terminal 22 to form a second solder mark portion 26.

[0393] The first wall 21a and the second wall 21b are adjacent and connected walls in the outer casing 21. Correspondingly, the thickness directions of the first wall 21a and the second wall 21b are perpendicular to each other. The first electrode terminal 22 is disposed on the second wall 21b, and the first electrode tab 242 is connected to the end of the main body 241 facing the first wall 21a in the first direction X. Correspondingly, the first electrode tab 242 is located on one side of the main body 241 in the first direction X, and the first electrode terminal 22 is located on one side of the main body 241 in the third direction Z.

[0394] The first current collector 23 may include an electrode connection portion 231 and a terminal connection portion 232 connected to each other. The electrode connection portion 231 is the part of the first current collector 23 located between the first wall 21a and the main body portion 241 in the first direction X and welded to the connection area 24211 of the multiple sub-electrodes 2421 of the first electrode 242 to form a first solder mark portion 25. The terminal connection portion 232 is the part located between the second wall 21b and the main body portion 241 in the third direction Z and welded to the first electrode terminal 22 to form a second solder mark portion 26, so that the first current collector 23 formed by the interconnection of the electrode connection portion 231 and the terminal connection portion 232 has an "L" shaped structure.

[0395] Optionally, the tab connection portion 231 and the terminal connection portion 232 of the first current collector 23 can be integrally formed or can be separately arranged and connected. If the tab connection portion 231 and the terminal connection portion 232 of the first current collector 23 are separately arranged and connected, the connection structure between the tab connection portion 231 and the terminal connection portion 232 can also be various, such as welding connection, snap-fit ​​connection, etc.

[0396] In this embodiment, the first electrode terminal 22 is disposed on the second wall 21b. By setting the tab connection portion 231 of the first current collector 23 to be located between the main body portion 241 and the first wall 21a in the first direction X and welded to the first tab 242, and setting the terminal connection portion 232 of the first current collector 23 to be located between the main body portion 241 and the second wall 21b in the third direction Z and welded to the first electrode terminal 22, the first tab 242 and the first electrode terminal 22 are respectively located on different sides of the main body portion 241, so that the first solder mark portion 25 and the second solder mark portion 26 are also respectively located on different sides of the main body portion 241. This enables the welding positions of the first current collector 23 and the first tab 242 and the welding positions of the first current collector 23 and the first electrode terminal 22 to be located on different sides of the main body portion 241, thereby reducing the interference between the welding assembly of the first current collector 23 and the first tab 242 and the welding assembly of the first current collector 23 and the first electrode terminal 22.

[0397] In some embodiments, see Figure 34 As shown, the tab connection portion 231 and the terminal connection portion 232 are integrally formed, that is, the tab connection portion 231 and the terminal connection portion 232 of the first current collector 23 are structures formed by an integral molding process.

[0398] For example, the tab connection portion 231 and the terminal connection portion 232 of the first current collector 23 are structures formed by bending the same metal piece.

[0399] In this embodiment, by setting the tab connection 231 and the terminal connection 232 as an integrally formed structure, the current flow effect between the tab connection 231 and the terminal connection 232 can be improved, and the connection reliability between the tab connection 231 and the terminal connection 232 can be improved, thereby reducing the risk of connection failure during use.

[0400] Of course, the structure of the first current collector 23 is not limited to this. In other embodiments, the tab connection 231 and the terminal connection 232 can also be separate and connected, such as by welding or snap-fit.

[0401] In this embodiment, by setting the tab connection portion 231 and the terminal connection portion 232 as separate components, it is possible to first weld and assemble the tab connection portion 231 and the first tab 242, as well as the terminal connection portion 232 and the first electrode terminal 22, and then connect the tab connection portion 231 and the terminal connection portion 232. This is beneficial for optimizing the production process and production cycle, and can reduce the welding difficulty between the tab connection portion 231 and the first tab 242, and between the terminal connection portion 232 and the first electrode terminal 22.

[0402] According to some embodiments of this application, see Figure 33 and Figure 34 As shown, at least one clearance notch 2311 is provided on at least one side of the tab connection portion 231 in the second direction Y, and the clearance notch 2311 penetrates the tab connection portion 231 along the first direction X. The clearance notch 2311 corresponds one-to-one with the first tabs 242. Along the first direction X, at least a portion of the tabs 2421 of each first tab 242 passes through a clearance notch 2311 and extends to the side of the tab connection portion 231 opposite to the main body portion 241.

[0403] The clearance notch 2311 on the tab connection portion 231 is a structure that is provided on one side of the tab connection portion 231 in the second direction Y and extends through the entire tab connection portion 231 in the first direction X, such that at least a portion of the tabs 2421 of each first tab 242 is a structure that passes through a clearance notch 2311 in the first direction X and then bends around the tab connection portion 231.

[0404] It should be noted that in an embodiment where a plurality of first electrode tabs 242 are connected to one end of the main body 241 facing the first wall 21a along the first direction X, and the plurality of first electrode tabs 242 are arranged at intervals along the third direction Z, a plurality of clearance notches 2311 are provided on the electrode tab connecting part 231, and the plurality of clearance notches 2311 are arranged at intervals along the second direction Y, with each clearance notch 2311 allowing one first electrode tab 242 to pass through. In an embodiment where the smoothing and bending directions of the plurality of first electrode tabs 242 in the second direction Y are the same, that is, in which the sub-electrode tabs 2421 of the plurality of first electrode tabs 242 are all bent toward one side of the main body 241 in the second direction Y, the electrode tabs 2421 of the plurality of first electrode tabs 242 are all bent toward one side of the main body 241 in the second direction Y. In the folded embodiment, multiple clearance notches 2311 are all provided on the same side of the tab connection portion 231 in the second direction Y. In the embodiment where at least two of the multiple first tabs 242 have opposite flattening and bending directions in the second direction Y, that is, in the embodiment where the sub-tab 2421 of one of the multiple first tabs 242 bends toward the side of the main body portion 241 in the second direction Y, and the sub-tab 2421 of the other first tab 242 bends toward the other side of the main body portion 241 in the second direction Y, clearance notches 2311 are provided on both sides of the tab connection portion 231 in the second direction Y.

[0405] For example, in Figure 33 and Figure 34 In the middle, the main body 241 has two first pole ears 242 connected to one end facing the first wall 21a in the first direction X. The two first pole ears 242 are arranged at intervals along the third direction Z. The sub-pole ear 2421 of one first pole ear 242 is bent towards one side of the main body 241 in the second direction Y, and the sub-pole ear 2421 of the other first pole ear 242 is bent towards the other side of the main body 241 in the second direction Y. Correspondingly, the pole ear connecting part 231 is provided with a clearance notch 2311 on both sides in the second direction Y. The two first pole ears 242 pass through the corresponding clearance notch 2311 and then bend towards each other in the second direction Y.

[0406] It should be noted that in the embodiment where the first electrode terminal 22 is disposed on the first wall 21a and multiple first electrode tabs 242 are welded to the same first current collector 23 to form a first solder mark 25, at least one side of the first current collector 23 in the second direction Y can also be provided with an avoidance notch 2311.

[0407] In this embodiment, by providing a clearance notch 2311 along the first direction X through the tab connection portion 231 on one side of the tab connection portion 231 along the second direction Y, and the clearance notch 2311 is used for at least a portion of the sub-tabs 2421 of the first tab 242 to pass through, on the one hand, it is convenient for the first tab 242 to bend towards the second direction Y after passing through the clearance notch 2311 to the side of the tab connection portion 231 away from the main body portion 241, and it can shorten the path length of each sub-tab 2421 bending around the tab connection portion 231, which is beneficial to reducing the difficulty of smoothing the bending of the first tab 242. On the other hand, it can realize that the tab connection portion 231 and the first tab 242 share space in the second direction Y, which is beneficial to improve the internal space utilization of the battery cell 20, and also beneficial to reduce the assembly difficulty of the tab connection portion 231 between the first wall 21a and the main body portion 241.

[0408] According to some embodiments of this application, refer to Figure 34 Please refer to further details. Figure 35 As shown, Figure 35 This is a cross-sectional view of the battery cell 20 provided in other embodiments of this application after the first current collector 23 and the first electrode terminal 22 are assembled together. The terminal connection portion 232 is provided with a mounting hole 2323, which penetrates the terminal connection portion 232 along the third direction Z. The first electrode terminal 22 has an insertion portion 227, at least a portion of which is inserted into the mounting hole 2323 along the third direction Z and welded to the terminal connection portion 232 to form a second solder mark portion 26.

[0409] The first electrode terminal 22 has a protruding insertion part 227 on the side facing the main body 241 in the third direction Z. The insertion part 227 is a structure that is inserted into the assembly hole 2323 along the third direction Z and then welded to the hole wall of the assembly hole 2323.

[0410] As an example, the mounting hole 2323 is a circular hole, and correspondingly, the insertion part 227 is cylindrical.

[0411] In this embodiment, by providing an assembly hole 2323 that penetrates the terminal connection portion 232 along a third direction Z, and inserting the insertion portion 227 of the first electrode terminal 22 into the assembly hole 2323 and welding it to the terminal connection portion 232, the welding assembly between the first electrode terminal 22 and the terminal connection portion 232 is achieved. The battery cell 20 with this structure can achieve the positioning and limiting function between the first electrode terminal 22 and the terminal connection portion 232 through the assembly structure of the assembly hole 2323 and the insertion portion 227, thereby reducing the risk of displacement or shaking of the first electrode terminal 22 and the terminal connection portion 232 during the welding assembly process. This is beneficial to improving the welding quality between the first electrode terminal 22 and the terminal connection portion 232, and further improving the connection reliability between the first electrode terminal 22 and the terminal connection portion 232.

[0412] In some embodiments, see Figure 35 As shown, along the third direction Z, the first electrode terminal 22 has a contact surface 228 facing the terminal connection portion 232, the insertion portion 227 protrudes from the contact surface 228, and the contact surface 228 abuts against the terminal connection portion 232.

[0413] The abutting surface 228 is the surface of the first electrode terminal 22 facing the main body 241 in the third direction Z and abutting against the terminal connection portion 232. Correspondingly, the insertion portion 227 is connected to the abutting surface 228.

[0414] In this embodiment, by abutting the first electrode terminal 22 with the protruding insertion portion 227 abutting the abutting surface 228 on the terminal connection portion 232, the positioning and limiting effects between the first electrode terminal 22 and the terminal connection portion 232 are further improved. This further reduces the risk of displacement or shaking of the first electrode terminal 22 and the terminal connection portion 232 during the welding assembly process, which is beneficial to further improve the welding quality between the first electrode terminal 22 and the terminal connection portion 232, and also beneficial to further improve the connection reliability between the first electrode terminal 22 and the terminal connection portion 232.

[0415] In some embodiments, please continue to see Figure 35As shown, the second solder mark 26 is provided around the insertion part 227, that is, the second solder mark 26 is an annular structure that extends circumferentially along the wall surface of the assembly hole 2323.

[0416] Of course, in other embodiments, the second solder mark 26 may also be other structures, such as the insertion part 227 and the hole wall of the assembly hole 2323 being welded together to form a plurality of second solder marks 26, and the plurality of second solder marks 26 being arranged circumferentially at intervals along the hole wall of the assembly hole 2323.

[0417] In this embodiment, by setting the second solder mark 26 to surround the insertion part 227, the insertion part 227 is inserted into the assembly hole 2323 and welded to the hole wall of the assembly hole 2323 to form a ring structure of the second solder mark 26. The battery cell 20 with this structure can increase the welding area between the first electrode terminal 22 and the terminal connection part 232, which is beneficial to further improve the connection stability and overcurrent effect between the first electrode terminal 22 and the terminal connection part 232.

[0418] According to some embodiments of this application, see Figure 31 , Figure 32 and Figure 33 As shown, the outer casing 21 also has a third wall 21c, which is disposed opposite to the first wall 21a in the first direction X, and the third wall 21c is connected to the second wall 21b. The electrode assembly 24 also includes a second tab 243, which has opposite polarity to the first tab 242, and is connected to the end of the main body 241 facing the third wall 21c in the first direction X. The battery cell 20 also includes a second electrode terminal 27 and a second current collector 28. The second electrode terminal 27 is disposed in the second wall 21b, and the second current collector 28 is disposed inside the outer casing 21. A portion of the second current collector 28 is located between the main body 241 and the third wall 21c and is connected to the second tab 243, and a portion of the second current collector 28 is located between the main body 241 and the second wall 21b and is connected to the second electrode terminal 27.

[0419] The third wall 21c is disposed opposite to the first wall 21a in the first direction X, and the second electrode tab 243 is connected to the end of the main body 241 facing the third wall 21c in the first direction X. That is to say, the first electrode tab 242 and the second electrode tab 243 with opposite polarities in the electrode assembly 24 are respectively connected to the two ends of the main body 241 in the first direction X, so that the electrode assembly 24 has an electrode tab structure at both ends in the first direction X.

[0420] For example, the first electrode terminal 22 and the second electrode terminal 27 are both disposed on the second wall 21b, and the first electrode terminal 22 and the second electrode terminal 27 are arranged at intervals along the first direction X.

[0421] It should be noted that the second electrode tab 243 connected to the end of the main body 241 facing the third wall 21c in the first direction X can be one or more. Similarly, the connection structure between the second current collector 28 and the second electrode tab 243 can be the same as the connection structure between the first current collector 23 and the first electrode tab 242. Of course, the connection structure between the second current collector 28 and the second electrode terminal 27 can also be the same as the connection structure between the first current collector 23 and the first electrode terminal 22.

[0422] In this embodiment, the outer casing 21 also has a third wall 21c disposed opposite to the first wall 21a in the first direction X, and the second tab 243 of the electrode assembly 24 is connected to the end of the main body 241 facing the third wall 21c, so that the electrode assembly 24 has a structure with the first tab 242 and the second tab 243 with opposite polarities at both ends in the first direction X, thereby reducing the risk of short circuit and interference between the first tab 242 and the second tab 243, and reducing the risk of short circuit and interference between the first current collector 23 and the second current collector 28, thereby improving the reliability of the battery cell 20 while reducing the assembly difficulty of the battery cell 20.

[0423] According to some embodiments of this application, see Figure 29 as well as Figure 31 and Figure 33 As shown, the electrode assembly 24 may include a plurality of first tabs 242 with the same polarity. The plurality of first tabs 242 are all connected to the end of the main body 241 facing the first wall 21a and are spaced apart along the third direction Z. The plurality of first tabs 242 are all welded to the first current collector 23 to form a first solder mark 25. The first direction X, the second direction Y and the third direction Z are perpendicular to each other.

[0424] In this embodiment, multiple first tabs 242 are welded to the first current collector 23 to form a first solder mark 25. This can be a structure in which multiple first tabs 242 are welded to the same first current collector 23, or a structure in which each first tab 242 is welded to one first current collector 23. That is, the battery cell 20 is provided with multiple first current collectors 23, and the first current collectors 23 are arranged in a one-to-one correspondence with the first tabs 242. Of course, in embodiments where there are multiple first current collectors 23, it can be a structure in which multiple first current collectors 23 are connected to the same first electrode terminal 22, or a structure in which each first current collector 23 is connected to one first electrode terminal 22. That is, the battery cell 20 is provided with multiple first electrode terminals 22, and the first current collectors 23 are arranged in a one-to-one correspondence with the first electrode terminals 22.

[0425] As an example, in Figure 29 and Figure 31 In this configuration, multiple first tabs 242 are all welded and assembled to the same first current collector 23 to form multiple first solder marks 25. Furthermore, the multiple first tabs 242 are welded and connected to different positions of the first current collector 23 to form first solder marks 25. It should be noted that the multiple first tabs 242 are arranged at intervals along a third direction Z. This can be a structure where all the multiple first tabs 242 are located on the same side of the first electrode terminal 22 in the third direction Z, or a structure where first tabs 242 are provided on both sides of the first electrode terminal 22 in the third direction Z, or a structure where at least some of the multiple first tabs 242 are arranged in the first direction X along with the first electrode terminal 22.

[0426] In this embodiment, by providing a plurality of first tabs 242 arranged at intervals along the third direction Z and having the same polarity at one end of the main body 241 facing the first wall 21a, and by welding the plurality of first tabs 242 to the first current collector 23 to form a first solder mark 25, the battery cell 20 with this structure can, on the one hand, increase the current flow area and current flow path between the main body 241 and the first current collector 23 to improve the current flow effect between the main body 241 and the first current collector 23. On the other hand, when some of the first tabs 242 have unstable connection or connection failure with the first current collector 23, the remaining first tabs 242 can still achieve electrical connection between the main body 241 and the first current collector 23, thereby effectively improving the stability and service life of the battery cell 20.

[0427] In some embodiments, see Figure 29 as well as Figure 33 As shown, in the second direction Y, the bending direction of the sub-taper 2421 of one first electrode 242 is opposite to the bending direction of the sub-taper 2421 of the other first electrode 242.

[0428] In the second direction Y, the bending direction of the sub-taper 2421 of one first electrode 242 is opposite to the bending direction of the sub-taper 2421 of the other first electrode 242. That is, in the second direction Y, the sub-taper 2421 of one first electrode 242 bends toward one side of the main body 241, while the sub-taper 2421 of the other first electrode 242 bends toward the other side of the main body 241, so that at least two of the multiple first electrodes 242 have opposite smoothing bending directions. Correspondingly, in the embodiments of this application, the connection areas 24211 of a plurality of sub-taper 2421 are stacked on the side of the first current collector 23 away from the main body 241. Then, the sub-taper 2421 of one first current collector 242 is a structure that bends from one side of the first current collector 23 in the second direction Y and extends to the side of the first current collector 23 away from the main body 241, and the sub-taper 2421 of another first current collector 242 is a structure that bends from the other side of the first current collector 23 in the second direction Y and extends to the side of the first current collector 23 away from the main body 241. That is, at least two first current collectors 242 are respectively flattened and bent from both sides of the first current collector 23 in the second direction Y to the side of the first current collector 23 away from the main body 241.

[0429] It should be noted that, in the embodiments of this application, the connection areas 24211 of the plurality of sub-tabs 2421 are stacked on the side of the first current collector 23 away from the main body 241. In embodiments where the orthographic projections of the connection ends 24213 of all sub-tabs 2421 in the projection plane perpendicular to the first direction X do not overlap with the orthographic projections of the first current collector 23 in the projection plane perpendicular to the first direction X, such as... Figure 13As shown, the multiple sub-tabs 2421 in the same first electrode tab 242 are connected only to a portion of the multiple first electrode segments 2411a, that is, each sub-tab 2421 is only connected to a portion of the multiple first electrode segments 2411a. If the electrode assembly 24 is a wound structure, the first electrode segments 2411a not connected to the sub-tabs 2421 can be guided through the first bending section 2411b and other first electrode segments 2411a. Correspondingly, the first electrode tabs 242 connected to the main body 241 can be one or multiple, and can be a structure in which the smoothing and bending directions of multiple first electrode tabs 242 are all the same. It can be a structure with at least two first electrode tabs 242 having opposite smoothing and bending directions. If the electrode assembly 24 is a stacked structure, the first electrode segment 2411a that is not connected to the sub-electrode tab 2421 cannot conduct current, and there is a phenomenon of partial failure of the first electrode segment 2411a. Therefore, there are multiple first electrode tabs 242 connected to the main body 241, and at least two first electrode tabs 242 have opposite smoothing and bending directions. That is, in the second direction Y, the bending direction of the sub-electrode tab 2421 of one first electrode tab 242 is opposite to the bending direction of the sub-electrode tab 2421 of another first electrode tab 242. Correspondingly, each first electrode segment 2411a is connected to at least one sub-electrode tab 2421.

[0430] In this embodiment, by setting the bending direction of the sub-taper 2421 of one first electrode 242 in the second direction Y to be opposite to that of the sub-taper 2421 of another first electrode 242 in the second direction Y, the smoothing bending directions of at least two first electrodes 242 are opposite. Using this structure, the battery cell 20 can achieve a reversed stacking order of the connection areas 24211 of multiple sub-taper 2421 in at least two first ...

Claims

1. A battery cell, characterized in that, include: The outer shell has a first wall, the thickness direction of which is parallel to a first direction; A first electrode terminal is disposed on the housing; At least one electrode assembly is housed within the housing. The electrode assembly includes a main body and a first electrode tab. The main body includes a plurality of first electrode segments stacked along a second direction and having the same polarity. The first electrode tab includes a plurality of sub-electrode tabs stacked together. Each sub-electrode tab of each first electrode tab is connected to one end of a first electrode segment near the first wall, and the sub-electrode tab is bent toward the second direction, which is perpendicular to the first direction. as well as A first current collector is at least partially disposed between the main body and the first wall, and the first current collector is connected to the first electrode terminal; Along the first direction, the sub-tab has a connection area located on the side of the first current collector opposite to the main body. The connection areas of multiple sub-tabs of each first tab are stacked and welded to the first current collector to form at least one first solder mark. The first tab has a first surface opposite to the main body. At least a portion of each first solder mark extends from the first surface through at least a portion of the connection area and into the first current collector. Two adjacent connection areas are fixedly connected only by the first solder mark. Among the multiple connection areas, the dimension of the connection area furthest from the main body in the second direction is greater than the dimension of the connection area closest to the main body in the second direction.

2. The battery cell according to claim 1, characterized in that, The connection region furthest from the main body among the plurality of connection regions has the largest size in the second direction.

3. The battery cell according to claim 1, characterized in that, In at least two adjacent connection regions, the dimension of the connection region farther from the main body in the second direction is greater than the dimension of the connection region closer to the main body in the second direction.

4. The battery cell according to claim 3, characterized in that, The plurality of sub-tabs include a first sub-tab, wherein the connection region of the first sub-tab is the connection region closest to the main body among the plurality of connection regions; The dimension of the connection area of ​​the first sub-taper in the second direction is greater than or equal to 5 mm.

5. The battery cell according to claim 3, characterized in that, The plurality of sub-tabs include a first sub-tab, wherein the connection region of the first sub-tab is the connection region closest to the main body among the plurality of connection regions; At least one of the first solder marks extends beyond the first sub-electrode tab in the second direction from one end away from the first electrode segment.

6. The battery cell according to claim 3, characterized in that, The area through which the first solder mark passes by the sub-electrode forms a solder mark area; In at least two adjacent connection areas, the solder area on the connection area farther from the main body has a larger size in the second direction than the solder area on the connection area closer to the main body has a larger size in the second direction.

7. The battery cell according to claim 1, characterized in that, The plurality of sub-taps includes a second sub-tap, wherein the connection region of the second sub-tap is the connection region furthest from the main body among the plurality of connection regions; In a projection plane perpendicular to the first direction, the orthographic projection of all the first solder marks in the same first tab is located within the orthographic projection of the second sub-tab.

8. The battery cell according to claim 1, characterized in that, Along the first direction, at least one of the first solder marks passes through the connection area of ​​all the sub-tabs in the first tab.

9. The battery cell according to claim 1, characterized in that, Along the first direction, the thickness of the portion of the first solder mark extending into the first current collector is T1, and the thickness of the region where the first current collector is connected to the first solder mark is T2, satisfying 0.25≤T1 / T2≤0.

75.

10. The battery cell according to claim 1, characterized in that, Along the first direction, the thickness of the area where the first current collector is connected to the first solder mark is 0.3mm-4mm.

11. The battery cell according to claim 1, characterized in that, The extension dimension of the sub-electrode from one end connected to the first electrode segment to the end away from the first electrode segment is 5mm-40mm.

12. The battery cell according to claim 1, characterized in that, In the projection plane perpendicular to the first direction, the orthographic projection of the first solder mark is a strip structure extending along a straight trajectory, and the length direction of the orthographic projection of the first solder mark is parallel to the second direction or the angle between the length direction of the orthographic projection of the first solder mark and the second direction is less than or equal to 30°.

13. The battery cell according to claim 12, characterized in that, The first electrode tab has multiple first solder marks, which are arranged at intervals along a third direction, with the first direction, the second direction, and the third direction being perpendicular to each other.

14. The battery cell according to claim 13, characterized in that, Along the third direction, the minimum distance between two adjacent first solder marks is 1mm-10mm.

15. The battery cell according to claim 13, characterized in that, Each of the said sub-tabs is fixedly connected to at least two of the first solder pads.

16. The battery cell according to claim 12, characterized in that, In a projection plane perpendicular to the first direction, the width of the orthographic projection of the first solder mark in the third direction is 0.5mm-5mm, and the first direction, the second direction, and the third direction are perpendicular to each other.

17. The battery cell according to claim 1, characterized in that, The area through which the first solder mark passes through the sub-electrode tab forms a solder mark area. The surface area of ​​one side of the sub-electrode tab in its thickness direction is S1, and the sum of the areas of all the solder marks on the same sub-electrode tab is S2, satisfying that 0.0075≤S2 / S1≤0.

1.

18. The battery cell according to claim 1, characterized in that, The sub-electrode has a connection end connected to the first pole segment. In a projection plane perpendicular to the first direction, at least a portion of the orthographic projection of the connection end of the sub-electrode is located within the orthographic projection of the first current collector, and the sub-electrode whose orthographic projection of the connection end is located within the orthographic projection of the first current collector is bent around the first current collector.

19. The battery cell according to claim 18, characterized in that, Along the first direction, the portion of the sub-electrode located between the first current collector and the main body gradually moves away from the main body from one end connected to the first pole segment to the end away from the first pole segment.

20. The battery cell according to claim 1, characterized in that, The sub-electrode has a connection end connected to the first pole segment, and in a projection plane perpendicular to the first direction, the orthographic projection of the first current collector does not overlap with the orthographic projection of the connection end of all the sub-electrodes.

21. The battery cell according to claim 1, characterized in that, The battery cell also includes: A heat insulation component is disposed at least partially between the first current collector and the main body in the first direction, and at least a portion of the orthographic projection of the first solder mark is located within the orthographic projection of the heat insulation component in a projection plane perpendicular to the first direction.

22. The battery cell according to claim 21, characterized in that, In a projection plane perpendicular to the first direction, the orthographic projection of the first solder mark is entirely located within the orthographic projection of the heat insulation component.

23. The battery cell according to claim 21, characterized in that, The heat insulation component is made of insulating material.

24. The battery cell according to claim 21, characterized in that, The heat insulation element is connected to the surface of the first current collector facing the main body.

25. The battery cell according to claim 1, characterized in that, The battery cell also includes: The support member is supported between the first current collector and the main body along the first direction, and at least a portion of the orthographic projection of the first solder mark is located within the orthographic projection of the support member in a projection plane perpendicular to the first direction.

26. The battery cell according to any one of claims 1-25, characterized in that, The first electrode terminal is disposed on the first wall, the first current collector is disposed between the main body and the first wall in the first direction, and the first current collector and the first electrode terminal are welded together to form a second solder mark.

27. The battery cell according to claim 26, characterized in that, Along the first direction, the outer surface of the first electrode terminal opposite to the main body includes a second surface, and at least a portion of the second solder mark extends from the second surface into the first current collector.

28. The battery cell according to claim 26, characterized in that, The first electrode terminal includes a first connecting portion located within the housing, the first connecting portion having a first side surface and a third surface facing the main body in the first direction, the first side surface surrounding the third surface and being connected to the third surface; The first current collector includes an interconnected tab connection portion and a terminal connection portion. Along the first direction, the connection areas of a plurality of sub-tabs of each first tab are stacked on the side of the tab connection portion away from the main body and welded to the tab connection portion to form the first solder mark portion. The terminal connection portion extends in the direction away from the main body and is welded to the first side to form the second solder mark portion.

29. The battery cell according to claim 26, characterized in that, The first current collector is located between the main body and the first electrode terminal, and the first current collector includes a tab connection portion, a bending portion and a terminal connection portion connected in sequence; Along the first direction, the connection areas of the plurality of sub-tabs of each first tab are stacked on the side of the tab connection portion away from the main body portion and are welded to the tab connection portion to form the first solder mark portion, and the terminal connection portion is located on the side of the tab connection portion facing the first electrode terminal and is welded to the first electrode terminal to form the second solder mark portion.

30. The battery cell according to claim 26, characterized in that, The electrode assembly includes a plurality of first electrode tabs with the same polarity. The plurality of first electrode tabs are all connected to the end of the main body facing the first wall and are spaced apart along a third direction. The plurality of first electrode tabs are all welded to the first current collector to form the first solder mark. The first direction, the second direction and the third direction are perpendicular to each other. Along the third direction, a portion of the first tabs are located on one side of the first electrode terminal, and another portion of the first tabs are located on the other side of the first electrode terminal.

31. The battery cell according to any one of claims 1-25, characterized in that, The outer casing has a first wall and a second wall that are connected to each other. The first electrode terminal is disposed on the second wall. The thickness direction of the second wall is parallel to a third direction. The first direction, the second direction and the third direction are perpendicular to each other. The first current collector includes an interconnected tab connection portion and a terminal connection portion. The tab connection portion is disposed between the main body and the first wall in the first direction, and the connection areas of multiple sub-tabs of each first tab are stacked on the side of the tab connection portion away from the main body and welded to the tab connection portion to form the first solder mark portion. The terminal connection portion is disposed between the main body and the second wall in the third direction and welded to the first electrode terminal to form the second solder mark portion.

32. The battery cell according to claim 31, characterized in that, The electrode connecting part and the terminal connecting part are integrally formed; or The tab connection part and the terminal connection part are integrally disposed and connected.

33. The battery cell according to claim 31, characterized in that, The electrode connecting portion has at least one clearance notch on at least one side in the second direction, and the clearance notch penetrates the electrode connecting portion along the first direction; The clearance notch corresponds one-to-one with the first electrode tab. Along the first direction, at least a portion of the sub-electrode tab of each first electrode tab passes through one of the clearance notches and extends to the side of the electrode tab connection portion away from the main body portion.

34. The battery cell according to claim 31, characterized in that, The terminal connection portion is provided with an assembly hole, which penetrates the terminal connection portion along the third direction; The first electrode terminal has a plug portion, at least a portion of which is inserted into the mounting hole along the third direction and welded to the terminal connection portion to form the second solder mark portion.

35. The battery cell according to claim 34, characterized in that, Along the third direction, the first electrode terminal has an abutting surface facing the terminal connection portion, the insertion portion protrudes from the abutting surface, and the abutting surface abuts against the terminal connection portion.

36. The battery cell according to claim 34, characterized in that, The second solder mark is arranged around the plug portion.

37. The battery cell according to claim 31, characterized in that, The outer casing also has a third wall, which is disposed opposite to the first wall in the first direction and is connected to the second wall. The electrode assembly further includes a second electrode tab, which has the opposite polarity to the first electrode tab and is connected to the end of the main body facing the third wall in the first direction. The battery cell further includes a second electrode terminal and a second current collector. The second electrode terminal is disposed on the second wall, and the second current collector is disposed inside the housing. A portion of the second current collector is located between the main body and the third wall and is connected to the second electrode tab.

38. The battery cell according to any one of claims 1-25, characterized in that, The electrode assembly includes a plurality of first electrodes with the same polarity. The plurality of first electrodes are all connected to the end of the main body facing the first wall and are spaced apart along a third direction. The plurality of first electrodes are all welded to the first current collector to form the first solder mark. The first direction, the second direction and the third direction are perpendicular to each other.

39. The battery cell according to claim 38, characterized in that, In the second direction, the bending direction of the sub-taper of one first electrode is opposite to the bending direction of the sub-taper of the other first electrode.

40. The battery cell according to claim 39, characterized in that, The electrode assembly has a stacked structure. The main body includes a plurality of first electrode plates and a plurality of second electrode plates. The first electrode plates and the second electrode plates have opposite polarities. The first electrode plates and the second electrode plates are alternately stacked along the second direction. The first electrode is the first electrode segment, and each first electrode segment is connected to the sub-electrode tab at one end near the first wall in the first direction, and each sub-electrode tab is fixedly connected to the first solder mark.

41. A battery device, characterized in that, Includes the battery cell as described in any one of claims 1-40.

42. An electrical appliance, characterized in that, Includes a battery cell as described in any one of claims 1-40, the battery cell being used to provide electrical energy.

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