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. The electrode assembly comprises a main body part and a first tab, the main body part comprises a plurality of first pole segments stacked along a second direction, and the first tab comprises a plurality of sub-tabs connected to one end of the first pole segment close to a first wall. At least part of the first current collecting member is arranged between the main body part and the first wall and connected to the first electrode terminal. The plurality of sub-tabs are bent towards the second direction and partially stacked on one side of the first current collecting member in a first direction and welded to the first current collecting member. The sub-tab has a connecting end connected to the first pole segment. In a projection plane perpendicular to the first direction, the orthographic projection of the first current collecting member and the orthographic projection of the connecting end of all the sub-tabs do not overlap, so as to reduce the bending difficulty of the sub-tab and improve the energy density of the battery monomer.

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, the internal space utilization rate of existing battery cells is low, which is not conducive to improving the energy density 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 which is 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 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, each of the sub-tabs of each first tab being connected to one end of a first electrode segment near the first wall, the second direction being 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; the plurality of sub-tabs are bent toward the second direction, and portions of the plurality of sub-tabs are stacked on one side of the first current collector in the first direction and welded to the first current collector, the sub-tabs having a connection end connected to the first electrode 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-tabs.

[0006] In the above technical solution, the first electrode ear includes a plurality of sub-electrodes stacked together. The plurality of sub-electrodes of the first electrode ear are bent toward the second direction, and portions of the plurality of sub-electrodes are stacked on one side of the first current collector in the first direction and welded to the first current collector to achieve assembly connection between the first electrode ear and the first current collector. Specifically, by setting the orthographic projections of the connection ends of all sub-electrodes in a projection plane perpendicular to the first direction to a structure that does not overlap with the orthographic projections of the first current collector in a projection plane perpendicular to the first direction, the sub-electrodes are such that they start from one side of the first current collector in the second direction and bend around the first current collector. The structure extending to one side of the first current collector in the first direction allows the battery cell to reduce the difficulty of smoothing and bending the sub-tabs towards the second direction, and also reduces the difficulty of stacking and welding multiple sub-tabs of the first current collector to the first current collector. Furthermore, it enables the first current collector and the first current collector to share some space in the first direction, and further optimizes the dimensions of the first current collector and the main body in the first direction. This saves the space occupied by the first current collector and the first current collector as a whole in the first direction, thereby improving the internal space utilization of the battery cell and ultimately increasing the energy density of the battery cell.

[0007] In some embodiments, the sub-electrode includes a root region and a connection region located on one side of the first current collector in the first direction. The root region connects the first electrode segment and the connection region, and the connection region is welded to the first current collector. The root region is located on one side of the first current collector in the first direction, and in a projection plane perpendicular to the first direction, a portion of the orthographic projection of the root region is located within the orthographic projection of the first current collector.

[0008] In the above technical solution, the root region of the sub-tab used to connect the connection area and the first electrode segment is set to be located on one side of the first current collector in the first direction. This facilitates the smoothing and bending of the sub-tab towards the second direction, reduces the difficulty of smoothing and bending the sub-tab towards the second direction, and reduces the interference between the root region and the first current collector. In addition, by setting the portion of the root region's orthographic projection in the projection plane perpendicular to the first direction as a structure located within the orthographic projection of the first current collector in the projection plane perpendicular to the first direction, the area where the sub-tab connects to the first electrode segment or the area where the sub-tab is bent can share some space with the first current collector in the first direction. This saves the space occupied by the first electrode and the first current collector as a whole in the first direction, thereby improving the internal space utilization of the battery cell and increasing the energy density of the battery cell.

[0009] In some embodiments, the first pole segment includes a first current collector and a coating layer disposed on at least one side of the first current collector, the root region being connected to one end of the first current collector near the first wall along the first direction, and a portion of the coating layer extending onto the root region; in a projection plane perpendicular to the first direction, at least a portion of the orthographic projection of the region of the root region where the coating layer is disposed is located within the orthographic projection of the first current collector.

[0010] In the above technical solution, by setting the coating layer on the first electrode segment as a structure extending to the root region of the sub-electrode, the forming difficulty of the sub-electrode is reduced when cutting and forming the sub-electrode on the first electrode segment. The coating layer can also enhance the structural strength of the area where the sub-electrode is connected to the first electrode segment, thereby reducing the risk of cracking or breakage at the end where the sub-electrode is connected to the first electrode segment. Since the area where the coating layer is set at the root is more difficult to bend, at least a portion of the orthographic projection of the area where the coating layer is set at the root in the projection plane perpendicular to the first direction is set as a structure located within the orthographic projection of the first current collector in the projection plane perpendicular to the first direction. This can increase the structural strength of the area where the sub-electrode is connected to the first electrode segment, thereby reducing the risk of breakage at the end where the sub-electrode is connected to the first electrode segment during use. It can also realize that the area where the coating layer is set at the root and the first current collector share part of the space in the first direction. Thus, it can reduce the risk of connection failure between the sub-electrode and the first electrode segment during use and effectively improve the internal space utilization of the battery cell, thereby improving the reliability and energy density of the battery cell.

[0011] In some embodiments, a plurality of the sub-electrodes are welded to the first current collector to form at least one first solder mark, each of the first solder marks passing through at least a portion of the sub-electrodes along the first direction, and two adjacent sub-electrodes are fixedly connected only through the first solder mark.

[0012] In the above technical solution, multiple sub-tabs are partially stacked on one side of the first current collector in the first direction and welded to the first current collector to form at least one first solder mark. Adjacent sub-tabs are fixedly connected only through the first solder mark. This battery cell structure allows for the multiple sub-tabs of the first electrode not to be fixedly connected or pre-welded after the first electrode is bent in the second direction and before being stacked and welded to the first current collector. This facilitates the smoothing and bending of the multiple sub-tabs of the first electrode before welding and assembling the first electrode and the first current collector. This allows the multiple sub-tabs to have relative movement and lateral movement during the smoothing and bending process, enabling each sub-tab to... The smoothing and bending process can adapt to the length changes caused by bending, thereby reducing the phenomenon of local stress concentration or local bulging of the sub-tabs during the smoothing and bending process. This can effectively improve the welding quality between the first tab and the first current collector, and effectively alleviate 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 tab and the first current collector during use, which is conducive to improving the stability and reliability of the battery cell. On the other hand, it can reduce the welding difficulty between the first tab and the first current collector after smoothing and bending, and facilitate the smoothing and bending of multiple sub-tabs of the first tab based on the first current collector, thereby reducing the bending difficulty of the sub-tabs.

[0013] In some embodiments, along the first direction, at least one of the first solder marks passes through all of the sub-tabs in the first tab.

[0014] In the above technical solution, by setting at least one first solder mark to pass through all the sub-tips in the corresponding first electrode tab, all the sub-tips in the first electrode tab are fixedly connected to at least the first solder mark, and each sub-tips 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 due to the sub-tips on some first electrode segments not being welded to the first current collector.

[0015] 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°.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] In some embodiments, along the third direction, the minimum distance between two adjacent first solder pads is 1mm-10mm.

[0020] 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.

[0021] In some embodiments, each of the sub-tabs is fixedly connected to at least two of the first solder pads.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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 solder mark and the main body in the first direction.

[0028] 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 solder mark and the main body, the first solder mark is a structure located on the side of the heat insulation component away from the main body in the first direction, and at least a portion of the orthogonal projection of the first solder mark in the projection plane perpendicular to the first direction is a structure located within the orthogonal projection of the heat insulation component in the projection plane perpendicular to the first direction, so that the heat insulation component can 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.

[0029] 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.

[0030] 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.

[0031] In some embodiments, the heat insulation element is made of an insulating material.

[0032] 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.

[0033] In some embodiments, the battery cell further includes a support member; the support member is supported between the first solder mark 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.

[0034] In the above technical solution, by providing a support member between the first solder mark 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 where the first current collector and the first tab are welded together. This reduces the welding gap between the first tab and the first current collector and reduces the shaking phenomenon of the first current collector during the welding assembly process. In turn, it reduces the risk of incomplete welding between the first tab and the first current collector, thereby improving the welding quality of the first tab and the first current collector.

[0035] In some embodiments, along the first direction, a plurality of the sub-tabs are partially welded to the first current collector and stacked on the side of the first current collector away from the main body. The first tab has a first surface away from the main body, and at least a portion of the first solder mark extends from the first surface into the first current collector.

[0036] In the above technical solution, by stacking multiple sub-tabs welded to the first current collector on the side of the first current collector away from the main body, and with at least a portion of the first solder mark extending from the first surface of the first tab into the first current collector, the first tab is partially located on the side of the first current collector away from the main body, and the first tab and the first current collector are welded and assembled in a first direction from the side of the first tab away from the first current collector. This battery cell structure facilitates the smoothing and bending of the multiple sub-tabs of the first tab beforehand. The structure of welding and assembling the first tab and the first current collector after bending allows each sub-tab to adapt to the length change caused by bending during the smoothing and bending process. This reduces the phenomenon of local stress concentration or local bulging of the sub-tab during the smoothing and bending process, and also reduces the risk of short circuit inside the battery cell caused by the sub-tab being inserted into the main body. On the other hand, it reduces the welding difficulty between the first tab and the first current collector after smoothing and bending, and facilitates the smoothing and bending of multiple sub-tabs of the first tab based on the first current collector, thereby reducing the bending difficulty of the sub-tab.

[0037] In some embodiments, along the first direction, the sub-electrode gradually moves away from the main body from one end connected to the first electrode segment to the position connected to the first solder mark.

[0038] 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 sub-tabs are set to gradually move away from the main body from one end connected to the first electrode segment to the position connected to the first solder mark. This reduces the phenomenon of local bulging or swelling of the sub-tabs due to stress, thereby reducing the risk of cracking or breaking of the sub-tabs during assembly or use. It also saves the space occupied by the first electrode in the first direction, thereby improving the energy density of the battery cell.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] In the above technical solution, when the portions of multiple sub-electrodes welded to the first current collector are stacked on the side of the first current collector away from the main body, 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 welded through, and can increase the molten pool depth 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 can also improve 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 helps to reduce the difficulty of multiple sub-electrodes bending towards the second direction and extending to the side of the first current collector away from the main body.

[0043] In some embodiments, along the first direction, a plurality of the sub-tabs are partially welded to the first current collector and are stacked between the first current collector and the main body, the first current collector having a second surface facing away from the main body, and at least a portion of the first solder mark extending from the second surface into the plurality of sub-tabs.

[0044] In the above technical solution, by stacking multiple sub-tabs and the first current collector in a layered manner on the side of the first current collector facing the main body, and with at least a portion of the first solder mark extending from the second surface of the first current collector into the first tab, the first current collector is partially located on the side of the first tab away from the main body and is welded and assembled with the first current collector and the first tab in a first direction from the side of the first current collector away from the first tab. The battery cell with this structure can, on the one hand, realize that the tooling fixture can be a structure that presses down on multiple sub-tabs and welds them by the first current collector when welding and assembling the first current collector and the first tab, so that the sub-tabs can always be pressed down by the first current collector during the welding and assembly process, thereby reducing the risk of local warping or cracking of the sub-tabs during the welding and assembly process, and reducing the welding gap between multiple sub-tabs to reduce the risk of false welding, which is conducive to improving the welding quality between the first current collector and the first tab. On the other hand, it can reduce the welding difficulty between the first tab and the first current collector after smoothing and bending.

[0045] 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 0.2 mm to 4 mm.

[0046] In the above technical solution, when the portions of multiple sub-tabs welded to the first current collector are stacked on the side of the first current collector facing the main body, 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 0.2 mm to improve the structural strength of the first current collector. This can alleviate the phenomenon of deformation or warping of the first current collector caused by the clamping or pressing of the tooling fixture during the welding assembly process, thereby reducing the welding gap between the first current collector and the first electrode and between multiple sub-tabs during the welding assembly process, which is beneficial to reducing the risk of false welding. 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 to alleviate the phenomenon of the first current collector occupying too much space in the first direction. This is beneficial to improving the internal space utilization of the battery cell and can reduce the difficulty of the first solder mark passing through the first current collector before connecting to the first electrode, which is beneficial to reducing the welding difficulty between the first current collector and the first electrode.

[0047] 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.

[0048] In the above technical solution, on the one hand, 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 is set to be greater than or equal to 5mm. This reduces the difficulty of bending multiple sub-tabs towards the second direction and extending them to one side of the first current collector in the first direction. It also reduces the difficulty of stacking and welding multiple sub-tabs with the first current collector after bending. Furthermore, it helps to increase the area where the sub-tabs can be stacked and welded with the first current collector after bending. On the other hand, since the multiple sub-tabs of the first electrode segment are not fixed to each other before welding and assembling with the first current collector, the multiple sub-tabs can have relative movement and swaying capabilities during the smoothing and bending process of the first electrode segment. Thus, 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 be less than or equal to 40mm, the phenomenon of redundancy or local bulging of the sub-tabs after bending can be effectively alleviated. This helps to optimize the space occupied by the first electrode segment as a whole 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.

[0049] 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.

[0050] 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.

[0051] In some embodiments, along the first direction, the outer surface of the first electrode terminal opposite to the body portion includes a third surface, and at least a portion of the second solder portion extends from the third surface into the first current collector.

[0052] 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 third 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 smoothed, 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.

[0053] 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 fourth surface facing the main body in the first direction, the first side surface surrounding and connected to the fourth surface; the first current collector includes an interconnected tab connecting portion and a terminal connecting portion, along the first direction, portions of a plurality of sub-tabs of the first tab are stacked on one side of the tab connecting portion and welded to the tab connecting 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 a second solder mark portion.

[0054] 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.

[0055] 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, portions of a plurality of the sub-tabs of the first tab are stacked on one side of the tab connection portion and welded to the tab connection 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.

[0056] 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.

[0057] 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. 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.

[0058] 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.

[0059] 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 portions of a plurality of sub-electrodes of the first electrode tab are stacked on one side of the electrode tab connection portion and welded to the electrode tab connection portion, the terminal connection portion is disposed between the main body portion and the second wall in the third direction and welded to the first electrode terminal to form a second solder mark portion.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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, a plurality of the sub-tabs of each first tab are inserted into one clearance notch and extend to one side of the tab connection portion.

[0064] In the above technical solution, by providing a clearance notch that extends through the electrode connection part in the first direction along one side of the electrode connection part in the second direction, and the clearance notch is used for inserting at least part of the sub-electrodes of the first electrode, it is possible to facilitate the insertion of the bent part of the first electrode into the clearance notch or for the first electrode to bend in the second direction to one side of the electrode connection part in the first direction after passing through the clearance notch. It can also shorten the path length of each sub-electrode bending around the electrode connection part, which is beneficial to reducing the difficulty of smoothing the bending of the first electrode. On the other hand, it can realize that the electrode connection part and the first electrode share space in the second direction, which is beneficial to improve the internal space utilization of the battery cell and reduce the assembly difficulty of the electrode connection part being located between the first wall and the main body.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] In some embodiments, the second solder mark is disposed around the connector.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] In some embodiments, the electrode assembly includes a plurality of first tabs with the same polarity, the plurality of first tabs being connected to one end of the main body facing the first wall and spaced apart along a third direction, and the plurality of first tabs being welded to the first current collector, wherein the first direction, the second direction and the third direction are perpendicular to each other.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] In some embodiments, the electrode assembly is a wound structure, the electrode assembly has a flat region, and the electrode assembly includes a first electrode and a second electrode with opposite polarities. The first electrode includes a plurality of first electrode segments located within the flat region and stacked along the second direction. The electrode assembly includes only one first electrode tab. Alternatively, 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. The first direction, the second direction, and the third direction are perpendicular to each other.

[0078] In the above technical solution, since the orthographic projections of the connection ends of all the sub-electrodes in the projection plane perpendicular to the first direction do not overlap with the orthographic projections of the first current collector in the projection plane perpendicular to the first direction, the areas of the multiple first electrode segments corresponding to the first current collector in the first direction are structures without sub-electrodes. The electrode assembly is a wound structure, so that the multiple first electrode segments of the main body are all part of the first electrode sheet, and the multiple first electrode segments are interconnected, so that a first electrode segment can guide current not only through the sub-electrodes but also through other first electrode segments. Therefore, when the electrode assembly is a wound structure, the electrode assembly can be provided with only one first electrode to reduce manufacturing costs and assembly difficulty, or it can be provided with multiple first electrodes to increase the flow area and flow path.

[0079] 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, the first electrode plates and the second electrode plates are alternately stacked along the second direction, and the first electrode plate is a first electrode segment; 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 the third direction, the plurality of first electrode tabs are all welded to the first current collector, in the second direction, the bending direction of the sub-electrode tab of one first electrode tab is opposite to the bending direction of the sub-electrode tab of another first electrode tab, and each first electrode segment is connected to the sub-electrode tab at the end near the first wall in the first direction, the first direction, the second direction and the third direction are perpendicular to each other.

[0080] In the above technical solution, since the orthographic projections of the connection ends of all the sub-electrodes in the projection plane perpendicular to the first direction do not overlap with the orthographic projections of the first current collector in the projection plane perpendicular to the first direction, the areas of multiple first electrode segments corresponding to the first current collector in the first direction are structures without sub-electrodes. Since the electrode assembly is a stacked structure, the first electrode piece of the main body is a single first electrode segment. Each first electrode segment can only conduct current through its corresponding sub-electrodes. Therefore, when the electrode assembly is a stacked structure, multiple first electrodes need to be connected to the main body, and at least two first electrodes have opposite flattening and bending directions. Thus, by connecting at least one sub-electrode to each first electrode segment, each first electrode piece of the main body can be electrically connected to the first current collector, thereby reducing the risk of partial failure of the first electrodes of the electrode assembly.

[0081] Secondly, embodiments of this application also provide a battery device, including the aforementioned battery cell.

[0082] 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

[0083] 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.

[0084] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments; Figure 2Exploded 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 first electrode segment and the sub-electrode of the electrode assembly of a battery cell provided in some embodiments of this application, when unfolded and perpendicular to a third 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 a first direction; Figure 12 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 13 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 14 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 15 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 16 Exploded views of the battery cell structure provided in some embodiments of this application; Figure 17 A partial cross-sectional view of a battery cell perpendicular to a third direction, provided for some embodiments of this application; Figure 18A partial cross-sectional view of a battery cell provided in some embodiments of this application, perpendicular to the second direction, in other embodiments; Figure 19 Exploded views of the battery cell structure provided in other embodiments of this application; Figure 20 A partial cross-sectional view of a battery cell perpendicular to a third direction, provided for other embodiments of this application; Figure 21 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 22 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 23 A cross-sectional view of the first current collector of a battery cell provided in some other embodiments of this application; Figure 24 Exploded views of the battery cell structure are also provided in some embodiments of this application; Figure 25 This application also provides partial cross-sectional views of a battery cell perpendicular to a third direction in some embodiments; Figure 26 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 27 This application also provides a schematic diagram of the structure of the first current collector of a battery cell in some embodiments; Figure 28 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 29 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 30 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 31 Exploded views of the battery cell provided in some embodiments of this application in other embodiments; Figure 32 This is a schematic diagram of the structure of a battery cell provided in some other embodiments of this application; Figure 33 Exploded views of the battery cell structure provided in other embodiments of this application; Figure 34 A cross-sectional view of a battery cell perpendicular to the second direction, provided for other embodiments of this application; Figure 35A partial structural schematic diagram of a battery cell provided for other embodiments of this application; Figure 36 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 37 This is a cross-sectional view of the first current collector and the first electrode terminal of a battery cell after they are assembled together, according to some other embodiments of this application.

[0085] 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 - Third surface; 222 - Groove; 223 - Fifth surface; 224 - First connecting part; 2241 - First side; 2242 - Fourth surface; 2243 - Sixth surface; 225 - Second connecting part; 226 - Third connecting part; 227 - Insertion part; 228 - Abutting surface; 23 - First current collector; 23a - Second surface; 23b - Foil; 231 - Electrode connecting part; 2311 - Clearance notch; 232 - Terminal connecting part; 2321 - Seventh surface; 2322 - Eighth 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; 2411aa-First current collector; 2411ab-Coating layer; 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-Connecting end ; 2421b - Soldering area; 24211 - Root area; 24212 - Connection area; 2422 - First surface; 243 - Second electrode tab; 25 - First soldering part; 26 - Second soldering 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 - Winding direction. Detailed Implementation

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] In this application, "multiple" means two or more (including two).

[0093] 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.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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.).

[0099] 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.

[0100] 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.

[0101] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0102] 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.).

[0103] 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.

[0104] 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.

[0105] 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.

[0106] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0107] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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.

[0114] Among them, the gel electrolyte includes a polymer as the electrolyte backbone network, combined with an ionic liquid - lithium salt.

[0115] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0116] 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.

[0117] 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.

[0118] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0119] In some implementations, the electrode assembly has a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0120] In some implementations, the electrode assembly has a stacked structure.

[0121] As an example, multiple positive and negative electrodes can be set, and multiple positive and multiple negative electrodes can be stacked alternately.

[0122] 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.

[0123] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0124] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0125] As an example, the separators can be continuously arranged, either by folding or rolling between any adjacent positive or negative electrode plates.

[0126] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0127] 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.

[0128] 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.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0134] 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.

[0135] 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.

[0136] 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.

[0137] 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.

[0138] 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.

[0139] 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 end of the electrode assembly facing the end cap has a tab, which includes multiple sub-tabs stacked together and having the same polarity. The end cap also has electrode terminals that are electrically connected to the tabs of the electrode assembly. The electrode terminals are connected to the tabs through the current collector to realize the input or output of electrical energy of the battery cell. In related technologies, in order to reduce the difficulty of forming the tabs and the assembly difficulty between the current collector and the tabs, especially in prismatic battery cells, the multiple sub-tabs of the tab are usually pre-welded together, and then the tabs and current collectors are welded together and assembled. Finally, the tabs are bent to facilitate the assembly of the end cap and the shell. However, in this structure of battery cells, because the multiple sub-tabs of the tab are pre-welded together and then bent, the tabs occupy too much space in the thickness direction of the end cap, resulting in low internal space utilization of the battery cell and is not conducive to improving the energy density of the battery cell.

[0140] Based on the above considerations, in order to solve the problem of low energy density 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. The second direction 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. The plurality of sub-tabs are bent toward the second direction, and portions of the plurality of sub-tabs are stacked on one side of the first current collector in the first direction and welded to the first current collector. The sub-tabs have a connection end connected to the first electrode segment. 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 ends of all sub-tabs.

[0141] In this type of battery cell, the first electrode includes multiple sub-electrodes stacked together. These sub-electrodes are bent towards a second direction, and portions of the sub-electrodes are stacked on one side of the first current collector in the first direction and welded to it, thus achieving assembly connection between the first electrode and the first current collector. Specifically, by setting the orthographic projections of all the connection ends of the sub-electrodes in a projection plane perpendicular to the first direction to be non-overlapping with the orthographic projections of the first current collector in the same plane, the sub-electrodes are designed to start from one side of the first current collector in the second direction and bend around it. The structure extends to one side of the first current collector in the first direction. The battery cell with this structure can reduce the difficulty of smoothing and bending the sub-tabs towards the second direction, and can also 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, so as to improve the internal space utilization of the battery cell and thus improve the energy density of the battery cell.

[0142] 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 alleviate the problem of low space utilization within the battery cells, thereby increasing the energy density of the battery cells.

[0143] 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.

[0144] 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.

[0145] Please refer to Figure 1 , Figure 1This 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.

[0146] 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.

[0147] 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.

[0148] 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.

[0149] 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.

[0150] 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.

[0151] 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.

[0152] 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.

[0153] 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 , Figure 10 and Figure 11 , 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 24 of the electrode assembly 24 of the battery cell 20 provided in some embodiments of this application. Figure 10A cross-sectional view 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, when unfolded and perpendicular to the third direction Z. Figure 11 This 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. The second direction Y 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. A plurality of sub-electrode tabs 2421 are bent toward the second direction Y, and portions of the plurality of sub-electrode tabs 2421 are stacked on one side of the first current collector 23 in the first direction X and welded to the first current collector 23. The sub-electrode tabs 2421 have a connection end 2421a 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 end 2421a of all the sub-electrode tabs 2421.

[0154] 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.

[0155] 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.

[0156] 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.

[0157] 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.

[0158] It should be noted that the first wall 21a used to set the first electrode terminal 22 can be the end cap 212 of the housing 21, or it can be a wall of the housing 211 of the housing 21. For 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.

[0159] 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.

[0160] 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.

[0161] 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.

[0162] 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.

[0163] 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.

[0164] 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.

[0165] As an 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.

[0166] 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 2411aa 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 2411aa of the first tab 242 and the first current collector 2411aa can be formed by integrally cutting the same metal foil to form the first tab 242 and the first current collector 2411aa. 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 current collector of 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.

[0167] 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 first direction X. It should be noted that in embodiments where there are multiple first electrode tabs 242, each of the multiple first electrode tabs 242 is disposed at the end of the main body portion 241 facing the first wall 21a in the first direction X, and the multiple first electrode tabs 242 are arranged at intervals along the second direction Y. Correspondingly, it can be a structure in which the first electrode segment 2411a is connected to only one sub-electrode tab 2421 of one first electrode tab 242, or it can be a structure in which the first electrode segment 2411a is connected to one sub-electrode tab 2421 of a portion of the first electrode tabs 242, or it can be a structure in which the first electrode segment 2411a is connected to one sub-electrode tab 2421 of each first electrode tab 242.

[0168] The sub-taper 2421 bends towards the first direction X, and portions of multiple sub-taper 2421 are stacked along the first direction X. That is, the sub-taper 2421 has a structure where its 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 first direction X. It should be noted that the sub-taper 2421 can be a structure that bends only to one side towards the first direction X, so that the sub-taper 2421 includes only one bending position. Alternatively, the sub-taper 2421 can be a structure that first bends to one side towards the first direction X and then bends to the other side towards the first direction X, making the sub-taper 2421 a continuously bent structure including two bending positions. Similarly, the portions of multiple sub-taper 2421 that bend towards the first direction X and are stacked can be a structure located on the side of the first current collector 23 facing the main body 241, or a structure located on the side of the first current collector 23 away from the main body 241.

[0169] 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 11 In this structure, electrode assembly 24 has a wound structure, and the central axis of the wound electrode assembly 24 extends along the first direction X. Correspondingly, the main body 241 also has two bending regions 241b, and the two bending regions 241b are respectively connected to the two opposite ends of the straight region 241a in the second direction Y. The first direction X and the second direction Y are perpendicular to each other. Of course, if electrode assembly 24 has a stacked structure, refer to... Figure 12 As shown, Figure 12 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.

[0170] 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 second electrode segments 2412a are stacked and alternately arranged along the first direction X. 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.

[0171] 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 first direction X. Correspondingly, the first electrode segment 2411a is the first electrode plate 2411 and the second electrode segment 2412a is the second electrode plate 2412.

[0172] 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.

[0173] 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 first direction X. 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.

[0174] 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.

[0175] 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.

[0176] 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.

[0177] 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.

[0178] 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.

[0179] 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.

[0180] Multiple sub-taperes 2421 are partially stacked on one side of the first current collector 23 in the first direction X and welded to the first current collector 23. That is, in the same first electrode 242, the portions of multiple sub-taperes 2421 and the first current collector 23 are stacked together along the first direction X, such that each of the multiple sub-taperes 2421 has a portion located on the side of the first current collector 23 away from the main body 241 or facing the main body 241. This portion of the multiple sub-taperes 2421 is welded to the first current collector 23 to form a first solder mark 25. That is, the portion of the multiple sub-taperes 2421 that is fixedly connected to the first solder mark 25 is a structure in the first direction X stacked on the side of the first current collector 23 away from the main body 241 or facing the main body 241. Correspondingly, the first solder mark 25 is a region formed by welding multiple sub-taperes 2421 and the first current collector 23 to form a fused region or a region formed by welding to form a solder mark.

[0181] The sub-electrode 2421 has a connection end 2421a connected to the first pole segment 2411a, that is, the connection end 2421a of the sub-electrode 2421 is the end of the sub-electrode 2421 connected to the corresponding first pole segment 2411a.

[0182] 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 end 2421a of all the sub-taper 2421. That is, the projection of the connection end 2421a of the sub-taper 2421 in the first direction X does not fall into the first current collector 23.

[0183] In this embodiment, if the portions of the multiple sub-tabs 2421 fixedly connected to the first solder mark portion 25 are stacked in the first direction X on the side of the first current collector 23 facing away from the main body portion 241, then all the sub-tabs 2421 in the first tab 242 are not located between the first current collector 23 and the main body portion 241, so that the sub-tabs 2421 do not extend into the portion between the first current collector 23 and the main body portion 241. This ensures that all sub-tabs 2421 extend from one side of the first current collector 23 in the second direction Y, bend, and then extend to the side of the first current collector 23 facing away from the main body portion 241. It should be noted that in this embodiment, the first current collector 23 can be a structure that directly abuts against the main body portion 241, or it can be a structure that indirectly abuts against the main body portion 241 through other components, such as the heat insulation member 30 and / or the support member 31.

[0184] If the portions of multiple sub-tabs 2421 fixedly connected to the first solder mark 25 are stacked in the first direction X on the side of the first current collector 23 facing the main body 241, then the portions of the sub-tabs 2421 connected to the first electrode segment 2411a are not located between the first current collector 23 and the main body 241 in the first direction X, while the portions of the sub-tabs 2421 fixedly connected to the first solder mark 25 are located between the first current collector 23 and the main body 241 in the first direction X. This results in all sub-tabs 2421 extending from one side of the first current collector 23 in the second direction Y, bending, and then extending to the space between the first current collector 23 and the main body 241. It should be noted that in this embodiment, the first current collector 23 and the main body 241 are indirectly abutting, and at least a portion of multiple sub-tabs 2421 is provided between the first current collector 23 and the main body 241.

[0185] 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.

[0186] For example, the material of the first current collector 23 can be various, such as copper, iron, aluminum, steel or aluminum alloy.

[0187] 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.

[0188] 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.

[0189] For 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. Correspondingly, the first wall 21a is provided with a second electrode lead-out hole, which penetrates the first wall 21a along the first direction X. The second electrode terminal 27 passes through the second electrode lead-out hole of the first wall 21a and is insulated and installed on the first wall 21a. That is to say, no electrical connection is formed between the second electrode terminal 27 and the first wall 21a of the outer casing 21.

[0190] 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.

[0191] 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.

[0192] For example, the material of the second current collector 28 can be various, such as copper, iron, aluminum, steel or aluminum alloy.

[0193] 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.

[0194] In some embodiments, see Figure 3 and Figure 4As 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.

[0195] 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.

[0196] In this embodiment, the first electrode tab 242 includes a plurality of sub-electrodes 2421 stacked together. The plurality of sub-electrodes 2421 of the first electrode tab 242 are bent toward the second direction Y, and portions of the plurality of sub-electrodes 2421 are stacked on one side of the first current collector 23 in the first direction X and welded to the first current collector 23 to achieve assembly connection between the first electrode tab 242 and the first current collector 23. Specifically, by setting the orthographic projection of the connection ends 2421a of all sub-electrodes 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 sub-electrodes 2421 start from one side of the first current collector 23 in the second direction Y and wrap around the first current collector 23. The structure of the battery cell 20 extending to one side of the first current collector 23 after bending 3 in the first direction X has the following advantages: Firstly, it reduces the difficulty of smoothing and bending the sub-tabs 2421 towards the second direction Y, and also reduces the difficulty of stacking and welding the multiple sub-tabs 2421 of the first tab 242 with the first current collector 23. Secondly, it enables the first current collector 23 and the first tab 242 to share some space in the first direction X, and further optimizes 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 in the first direction X, improving the internal space utilization of the battery cell 20, and thus improving the energy density of the battery cell 20.

[0197] According to some embodiments of this application, see the attached diagram. Figure 6 , Figure 7 and Figure 8As shown, the sub-electrode 2421 includes a root region 24211 and a connecting region 24212 located on one side of the first current collector 23 in the first direction X. The root region 24211 connects the first electrode segment 2411a and the connecting region 24212, and the connecting region 24212 is welded to the first current collector 23. The root region 24211 is located on one side of the first current collector 23 in the first direction X, and in the projection plane perpendicular to the first direction X, the orthographic projection of the root region 24211 is located within the orthographic projection of the first current collector 23.

[0198] The sub-taper 2421 includes a root region 24211 and a connecting region 24212 that are interconnected. The connecting region 24212 of the sub-taper 2421 is the portion where the orthographic projection of the sub-taper 2421 on one side of the first current collector 23 in the first direction X overlaps with the orthographic projection of the first current collector 23 on the same projection plane. Correspondingly, the connecting regions 24212 of the multiple sub-tapers 2421 of each first current collector 242 are stacked on one side of the first current collector 23 in the first direction X and welded to the first current collector 23. At least one first solder mark 25 is formed, and the root region 24211 is the part of the sub-electrode 2421 that connects the first pole segment 2411a and the connecting region 24212, such that the first pole segment 2411a, the root region 24211 and the connecting region 24212 are connected in sequence, and in the projection plane perpendicular to the first direction X, the root region 24211 is the part where the orthographic projection of the sub-electrode 2421 and the orthographic projection of the first current collector 23 do not overlap, that is, in the projection plane perpendicular to the first direction X, the orthographic projection of the root region 24211 and the orthographic projection of the first current collector 23 do not have an overlapping area.

[0199] The root region 24211 is located on one side of the first current collector 23 in the first direction X, that is, the root region 24211 of the sub-electrode 2421 and the first current collector 23 are arranged along the first direction X.

[0200] In the projection plane perpendicular to the first direction X, a portion of the orthographic projection of the root region 24211 lies within the orthographic projection of the first current collector 23. That is, in the projection plane perpendicular to the first direction X, at least a portion of the orthographic projection of the root region 24211 and at least a portion of the orthographic projection of the first current collector 23 overlap each other.

[0201] In this embodiment, the root region 24211 of the sub-electrode 2421, which connects the connecting region 24212 and the first pole segment 2411a, is positioned on one side of the first current collector 23 in the first direction X. This facilitates the smoothing and bending of the sub-electrode 2421 towards the second direction Y, reducing the difficulty of smoothing and bending the sub-electrode 2421 towards the second direction Y, and also reducing the interference between the root region 24211 and the first current collector 23. Furthermore, by projecting the root region 24211 onto a plane perpendicular to the first direction X... The portion of the orthographic projection in the plane is configured as a structure located within the orthographic projection of the first current collector 23 in the projection plane perpendicular to the first direction X, so that the area where the sub-tab 2421 is connected to the first pole segment 2411a or the area where the sub-tab 2421 is bent can share part of the space with the first current collector 23 in the first direction X, thereby saving the space occupied by the first pole 242 and the first current collector 23 as a whole in the first direction X, thereby improving the internal space utilization rate of the battery cell 20 and increasing the energy density of the battery cell 20.

[0202] In some embodiments, combined with Figure 6 , Figure 8 , Figure 9 and Figure 10 As shown, the first pole segment 2411a includes a first current collector 2411aa and a coating layer 2411ab disposed on at least one side of the first current collector 2411aa. Along the first direction X, a root region 24211 is connected to one end of the first current collector 2411aa near the first wall 21a, and a portion of the coating layer 2411ab extends onto the root region 24211. In a projection plane perpendicular to the first direction X, at least a portion of the orthographic projection of the region of the root region 24211 where the coating layer 2411ab is disposed lies within the orthographic projection of the first current collector 23.

[0203] The first current collector 2411aa is a component in the first electrode segment 2411a that is connected to the root region 24211 of the sub-electrode 2421. Both the first current collector 2411aa and the sub-electrode 2421 serve to transmit current. For example, the first current collector 2411aa and the sub-electrode 2421 are integrally formed, that is, the first current collector 2411aa and the sub-electrode 2421 are formed by cutting the same metal foil.

[0204] The coating layer 2411ab is a component disposed on at least one side of the first current collector 2411aa in its thickness direction within the first electrode segment 2411a and undergoing an electrochemical reaction in the battery cell 20. If the first electrode segment 2411a is at least a portion of the positive electrode sheet, the coating layer 2411ab includes a positive electrode active material layer and an insulating protective layer disposed on the edge of the positive electrode active material layer near the end of the sub-electrode tab 2421 in the first direction X. The positive electrode active material layer includes a positive electrode active material. If the first electrode segment 2411a is at least a portion of the negative electrode sheet, the coating layer 2411ab is a negative electrode active material layer disposed on the first current collector 2411aa. The negative electrode active material layer includes a negative electrode active material. The specific structures of the positive electrode active material layer, the insulating protective layer, and the negative electrode active material layer can be found in related technologies and will not be described in detail here.

[0205] It should be noted that since the first current collector 2411aa and the sub-electrode 2421 are structures cut from the same metal foil, in order to reduce manufacturing difficulty, the coating layer 2411ab is usually applied to the same metal foil before the metal foil is cut. Furthermore, to improve the cutting quality of the first electrode segment 2411a, the first current collector 2411aa is usually cut in the area of ​​the metal foil where the coating layer 2411ab is located. With the sub-tab 2421, the coating layer 2411ab extends to the root region 24211 of the sub-tab 2421. It should be noted that if the first electrode segment 2411a is at least a part of the positive electrode, then the part of the insulating protective layer extends to the root region 24211 of the sub-tab 2421; if the first electrode segment 2411a is at least a part of the negative electrode, then the part of the negative electrode active material layer extends to the root region 24211 of the sub-tab 2421.

[0206] It should be noted that in the region where the coating layer 2411ab is provided in the root region 24211 of the sub-electrode 2421, the coating layer 2411ab strengthens the structural strength of this region, making the deformation and bending resistance of the region where the coating layer 2411ab is provided relatively strong. Therefore, during the process of the sub-electrode 2421 being smoothed and bent in the second direction Y, the region where the coating layer 2411ab is provided in the root region 24211 usually does not bend, making the region where the coating layer 2411ab is provided in the root region 24211 a structure extending along the first direction X, that is, the thickness direction of the region where the coating layer 2411ab is provided in the root region 24211 is parallel to the second direction Y. This helps to reduce the risk of cracking at the position where the sub-electrode 2421 is connected to the first electrode segment 2411a during bending in the second direction Y.

[0207] In a projection plane perpendicular to the first direction X, at least a portion of the orthographic projection of the region of the root region 24211 where the coating layer 2411ab is provided lies within the orthographic projection of the first current collector 23. That is, in a projection plane perpendicular to the first direction X, at least a portion of the orthographic projection of the region of the root region 24211 where the coating layer 2411ab is provided overlaps with at least a portion of the orthographic projection of the first current collector 23, so that at least a portion of the orthographic projection of the first current collector 23 and at least a portion of the orthographic projection of the coating layer 2411ab extending to the root region 24211 overlap.

[0208] In this embodiment, by setting the coating layer 2411ab on the first pole segment 2411a to extend to the root region 24211 of the sub-pole tab 2421, the forming difficulty of the sub-pole tab 2421 is reduced when cutting and forming the sub-pole tab 2421 on the first pole segment 2411a. Furthermore, the coating layer 2411ab can enhance the structural strength of the area where the sub-pole tab 2421 is connected to the first pole segment 2411a, thereby reducing the risk of cracking or breakage at the end where the sub-pole tab 2421 is connected to the first pole segment 2411a. Since the area of ​​the root region 24211 with the coating layer 2411ab is more difficult to bend, the area of ​​the root region 24211 with the coating layer 2411ab is projected onto a plane perpendicular to the first direction X. At least a portion of the shadow is configured as a structure located within the orthographic projection of the first current collector 23 in a projection plane perpendicular to the first direction X. This structure can increase the structural strength of the area where the sub-tab 2421 is connected to the first electrode segment 2411a, thereby reducing the risk of breakage at the end connected to the sub-tab 2421 and the first electrode segment 2411a during use. It can also allow the area where the coating layer 2411ab is provided in the root region 24211 to share part of the space with the first current collector 23 in the first direction X. This can reduce the risk of connection failure between the sub-tab 2421 and the first electrode segment 2411a during use and effectively improve the internal space utilization of the battery cell 20, thereby balancing the improvement of the reliability and energy density of the battery cell 20.

[0209] According to some embodiments of this application, in conjunction with Figure 6 , Figure 7 and Figure 8 As shown, a plurality of sub-tabs 2421 are welded to the first current collector 23 to form at least one first solder mark 25. Each first solder mark 25 passes through at least part of the sub-tab 2421 along the first direction X, and two adjacent sub-tabs 2421 are fixedly connected only through the first solder mark 25.

[0210] Each first solder mark 25 passes through at least a portion of the sub-electrode tabs 2421 along the first direction X. That is, the portion of the first solder mark 25 located within the first current collector 23 and the portion of the first solder mark 25 located within the first electrode tab 242 are arranged and connected along the first direction X. Each first solder mark 25 is fixedly connected to at least a portion of the sub-electrode tabs 2421. Correspondingly, the first solder mark 25 can be a structure in which some sub-electrode tabs 2421 are sequentially connected and stacked in the first direction X, or it can be a structure in which all sub-electrode tabs 2421 are sequentially connected and stacked in the first direction X.

[0211] In the sub-tab 2421, there is a connection area 24212 located on one side of the first current collector 23 in the first direction X. The first solder mark 25 is a structure that passes through the connection area 24212 of the multiple sub-tabs 2421 along the first direction X.

[0212] 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.

[0213] In this embodiment, a plurality of sub-tabs 2421 are partially stacked on one side of the first current collector 23 in the first direction X and welded to the first current collector 23 to form at least one first solder mark 25. Adjacent sub-tabs 2421 are fixedly connected only through the first solder mark 25. This battery cell 20, with this structure, allows for the pre-welding or fixed connection of the plurality of sub-tabs 2421 of the first electrode 242 before the first electrode 242 is bent toward the second direction Y and stacked and welded to the first current collector 23. This facilitates the smoothing and bending of the plurality of sub-tabs 2421 of the first electrode 242 before welding the first electrode 242 and the first current collector 23 together. This allows the plurality of sub-tabs 2421 to have relative movement and lateral movement capabilities during the smoothing and bending process of the first electrode 242, enabling each sub-tab to... During the smoothing and bending process, the tab 2421 can adapt to the length changes caused by bending, thereby reducing the phenomenon of local stress concentration or local bulging of the sub-tab 2421 during the smoothing and bending process. This can effectively improve the welding quality between the first tab 242 and the first current collector 23, and effectively alleviate the phenomenon of cracking or breakage of the sub-tab 2421 during assembly or use. This reduces the risk of unstable connection and connection failure between the first tab 242 and the first current collector 23 during use, which is conducive to improving the stability and reliability of the battery cell 20. On the other hand, it can reduce the welding difficulty between the first tab 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 tab 242 based on the first current collector 23, thereby reducing the bending difficulty of the sub-tab 2421.

[0214] In some embodiments, see Figure 6 As shown, along the first direction X, at least one first solder mark 25 passes through all the sub-tabs 2421 of the first electrode tab 242. That is, all the sub-tabs 2421 of the first electrode tab 242 are fixedly connected to at least one first solder mark 25. Correspondingly, at least one solder mark area 2421b is formed on each sub-tab 2421 of the first electrode tab 242 (in conjunction with...). Figure 9 (As shown).

[0215] In this embodiment, by setting at least one first solder mark 25 to pass through all the sub-taps 2421 in the corresponding first electrode tab 242, all the sub-taps 2421 in the first electrode tab 242 are 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 paths or connection failures in 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.

[0216] According to some embodiments of this application, refer to Figure 6 Please refer to further details. Figure 13 As shown, Figure 13 This 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.

[0217] 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.

[0218] Optionally, the first weld mark 25 formed by welding each first tab 242 to the first current collector 23 can be one or more.

[0219] 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.

[0220] 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.

[0221] In some embodiments, see Figure 13 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.

[0222] 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.

[0223] In some embodiments, please continue to see Figure 13 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.

[0224] Among them, Figure 13 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.

[0225] 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.

[0226] 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.

[0227] In some embodiments, combined with Figure 9 and Figure 13 As shown, each sub-pole tab 2421 is fixedly connected to at least two first solder pads 25.

[0228] Each sub-tab 2421 is fixedly connected to at least two first solder marks 25, that is, each sub-tab 2421 is passed through by at least two first solder marks 25, so that at least two solder marks 2421b are formed on each sub-tab 2421.

[0229] 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.

[0230] In some embodiments, see Figure 13 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.

[0231] Among them, Figure 13 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.

[0232] 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.

[0233] 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.

[0234] 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 2421b. 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 2421b on the same sub-electrode 2421 is S2, satisfying 0.0075≤S2 / S1≤0.1.

[0235] 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 2421b 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 2421b is formed on the sub-electrode 2421, then S2 is the area of ​​the solder area 2421b. If multiple solder areas 2421b are formed on the sub-electrode 2421, then S2 is the sum of the areas of the multiple solder areas 2421b.

[0236] 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.

[0237] 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.

[0238] In this embodiment, on the one hand, the sum of the areas of all solder areas 2421b 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 2421b 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.

[0239] According to some embodiments of this application, refer to Figure 4 , Figure 5 and Figure 6 Please refer to further details. Figure 14 , Figure 14 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 battery cell 20 may also include a heat insulation member 30, at least a portion of which is disposed between the first solder portion 25 and the main body portion 241 in the first direction X.

[0240] The heat insulation component 30 is at least partially located between the first solder mark 25 and the main body 241 in the first direction X, such that the first solder 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 solder mark 25 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. That is, the first solder mark 25 and the main body 241 are respectively located on both sides of the heat insulation component 30 in the first direction X, and at least part of the orthographic projection of the first solder mark 25 is located in the orthographic projection of the heat insulation component 30 in the projection plane perpendicular to the first direction X. That is, the heat insulation component 30 is a structure that covers at least part of the first solder mark 25 in the first direction X. It can be that the heat insulation component 30 only covers part of the first solder mark 25, or it can be that the heat insulation component 30 covers the entire first solder mark 25.

[0241] As an example, in Figure 6In the illustrated embodiment, the portions of the multiple sub-tabs 2421 welded to the first current collector 23 are stacked on the side of the first current collector 23 facing away from the main body 241. Correspondingly, the heat insulation member 30 is a structure disposed between the first current collector 23 and the main body 241 in the first direction X. Optionally, the connection structure of the heat insulation member 30 between the first current collector 23 and the main body 241 can be various. The heat insulation member 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. Similarly, the connection method between the heat insulation member 30 and the first current collector 23 or the main body 241 can also be various. For example, the heat insulation member 30 can be bonded to the first current collector 23 or the main body 241 by adhesive or double-sided adhesive.

[0242] As an example, in Figure 14 In the illustrated embodiment, the portions of multiple sub-tabs 2421 welded to the first current collector 23 are stacked on the side of the first current collector 23 facing the main body 241. Correspondingly, the heat insulation member 30 is a structure disposed in the first direction X between the portion of the first tab 242 welded to the first current collector 23 and the main body 241. Optionally, the connection structure of the heat insulation member 30 between the portion of the first tab 242 welded to the first current collector 23 and the main body 241 can be various. The heat insulation member 30 can be a structure connected to the surface of the portion of the first tab 242 welded to 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. Similarly, the connection method between the heat insulation member 30 and the first tab 242 or the main body 241 can also be various. For example, the heat insulation member 30 can be bonded to the first tab 242 or the main body 241 by adhesive or double-sided adhesive.

[0243] 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.

[0244] As an example, the material of the insulation element 30 may include polyimide or polytetrafluoroethylene, etc.

[0245] 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 solder mark 25 and the main body 241, the first solder mark 25 is a structure located on the side of the heat insulation member 30 facing away from the main body 241 in the first direction X, and 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 a structure located within the orthographic projection of the heat insulation member 30 in a projection plane perpendicular to the first direction X, so that the heat insulation member 30 can 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 electrode 242 burning the main body 241 and other components during the welding connection and formation of the first solder mark 25, thereby improving the assembly quality of the battery cell 20.

[0246] In some embodiments, see Figure 6 and Figure 14 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.

[0247] 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.

[0248] 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 solder joint 25 and the main body 241, but also provide insulation between the first current collector 23 and the main body 241 or between the portion of the first electrode tab 242 welded to the first current collector 23 and the main body 241.

[0249] 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.

[0250] 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.

[0251] According to some embodiments of this application, please refer to Figure 6 as well as Figure 14 As shown, the battery cell 20 may also include a support member 31, which is supported between the first solder portion 25 and the main body portion 241 along the first direction X, and at least a portion of the orthographic projection of the first solder portion 25 is located within the orthographic projection of the support member 31 in a projection plane perpendicular to the first direction X.

[0252] 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.

[0253] 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.

[0254] For example, in Figure 6 In the illustrated embodiment, the portions of the multiple sub-tabs 2421 welded to the first current collector 23 are stacked on the side of the first current collector 23 facing away from the main body 241. Correspondingly, the support member 31 can be a structure that directly abuts against the main body 241. Figure 14 In the illustrated embodiment, a plurality of sub-tabs 2421 are partially welded to the first current collector 23 and stacked on the side of the first current collector 23 facing the main body 241, so that a portion of the sub-tabs 2421 is located between the first current collector 23 and the main body 241 in the first direction X. Correspondingly, the support member 31 is a structure that abuts against the portion of the sub-tabs 2421 located between the first current collector 23 and the main body 241.

[0255] 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 solder joint 25, such that the support member 31 is a structure that indirectly abuts against the first current collector 23 via the heat insulation element 30 or the first tab 242 being welded to the first current collector 23. It should be noted that in this embodiment, the heat insulation element 30 may also be a structure connected to the support member 31.

[0256] In this embodiment, by providing a support member 31 between the first solder mark portion 25 and the main body portion 241, and at least a portion of the orthographic projection of the first solder mark portion 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 where the first current collector 23 and the first tab 242 are welded together. 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. In turn, it reduces the risk of poor welding between the first tab 242 and the first current collector 23, thereby improving the welding quality of the first tab 242 and the first current collector 23.

[0257] According to some embodiments of this application, see Figure 6 As shown, along the first direction X, a plurality of sub-tabs 2421 are partially stacked with the first current collector 23 on the side of the first current collector 23 away from the main body 241. The first tab 242 has a first surface 2422 away from the main body 241, and at least a portion of the first solder mark 25 extends from the first surface 2422 into the first current collector 23.

[0258] Along the first direction X, the portions of multiple sub-taps 2421 welded to the first current collector 23 are stacked on the side of the first current collector 23 away from the main body 241. That is, the portions of multiple sub-taps 2421 connected to the first solder mark 25 are stacked on the side of the first current collector 23 away from the main body 241. In other words, the portions of multiple sub-taps 2421 are stacked and located on the side of the first current collector 23 away from the main body 241, and the portions of multiple sub-taps 2421 located on the side of the first current collector 23 away from the main body 241 are welded to the first current collector 23 to form the first solder mark 25, such that the portion of the first solder mark 25 connected to the first tab 242 is located on the side of the first current collector 23 away from the main body 241.

[0259] The first tab 242 has a first surface 2422 facing away from the main body 241, and at least a portion of the first solder mark 25 extends from the first surface 2422 into the first current collector 23. That is, in the first direction X, the first solder mark 25 is a structure in which at least a portion extends 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. That is, when welding and assembling the first tab 242 and the first current collector 23, the welding equipment is a structure that welds and assembles the first tab 242 and the first current collector 23 from the side of the first tab 242 away from the main body 241 in the first direction X, so that the first solder mark 25 is a structure that first passes through a plurality of sub-tabs 2421 and is stacked on the side of the first current collector 23 away from the main body 241 and then extends into the first current collector 23.

[0260] 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.

[0261] In this embodiment, by stacking the portions of the multiple sub-tabs 2421 that are welded to the first current collector 23 on the side of the first current collector 23 away from the main body 241, and by having at least a portion of the first solder mark 25 extending from the first surface 2422 of the first tab 242 into the first current collector 23, the first tab 242 is partially located on the side of the first current collector 23 away from the main body 241, and is welded and assembled to the first current collector 23 from the side of the first tab 242 away from the first current collector 23 in the first direction X. This structure of the battery cell 20 facilitates the initial assembly of the multiple sub-tabs 2421 of the first tab 242. The structure of smoothing and bending the first tab 242 and the first current collector 23 before welding and assembling allows each sub-tab 2421 to adapt to the length change caused by bending during the smoothing and bending process. This reduces the phenomenon of local stress concentration or local bulging of the sub-tab 2421 during the smoothing and bending process, and also reduces the risk of short circuit inside the battery cell 20 caused by the sub-tab 2421 being inserted into the main body 241. On the other hand, it reduces the welding difficulty between the first tab 242 and the first current collector 23 after smoothing and bending, and facilitates the smoothing and bending of multiple sub-tabs 2421 of the first tab 242 based on the first current collector 23, thereby reducing the bending difficulty of the sub-tab 2421.

[0262] According to some embodiments of this application, in embodiments where multiple sub-tabs 2421 are partially stacked on the side of the first current collector 23 opposite to the main body 241, see [reference needed]. Figure 6 and Figure 8 As shown, along the first direction X, the sub-tab 2421 gradually moves away from the main body 241 from the end connected to the first electrode segment 2411a to the position connected to the first solder mark 25. In other words, in the first direction X, the distance between the sub-tab 2421 and the main body 241 gradually increases from the end connected to the first electrode segment 2411a to the position connected to the first solder mark 25.

[0263] It should be noted that since the sub-electrode 2421 has a portion located on the side of the first current collector 23 away from the main body 241 in the first direction X and is stacked with the first current collector 23, the sub-electrode 2421 gradually moves away from the main body 241 from one end connected to the first electrode segment 2411a to the position connected to the first solder mark 25 along the first direction X. Correspondingly, the sub-electrode 2421 can be partially inclined and gradually moves away from the main body 241 and partially extends along the second direction Y, or it can be 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. In an embodiment where the sub-electrode 2421 includes a root region 24211 and a connecting region 24212, the connecting region 24212 is a structure extending along the second direction Y, while the root region 24211 is a structure that gradually moves away from the main body 241 from one end connected to the first pole segment 2411a to one end connected to the connecting region 24212. The portion of the root region 24211 connected to the first pole segment 2411a is a structure extending along the first direction X, while the portion of the root region 24211 connected to the connecting region 24212 is a curved structure.

[0264] In this embodiment, since the first electrode tab 242 is bent toward the second direction Y and the multiple sub-tabs 2421 of the first electrode tab 242 are not fixedly connected or pre-welded before the first electrode tab 242 is stacked and welded with the first current collector 23, the multiple sub-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 sub-tabs 2421 are set to gradually move away from the main body 241 from one end connected to the first electrode segment 2411a to the position connected to the first solder mark 25. This reduces the phenomenon of local bulging or swelling of the sub-tabs 2421 due to stress, thereby reducing the risk of cracking or breaking of the sub-tabs 2421 during assembly or use, and saving the space occupied by the first electrode tab 242 in the first direction X, thereby improving the energy density of the battery cell 20.

[0265] According to some embodiments of this application, in embodiments where multiple sub-tabs 2421 are partially stacked on the side of the first current collector 23 opposite to the main body 241, see [reference needed]. 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.

[0266] 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.

[0267] 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.

[0268] 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 improve 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.

[0269] According to some embodiments of this application, in embodiments where multiple sub-tabs 2421 are partially stacked on the side of the first current collector 23 opposite to the main body 241, please refer to... 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.

[0270] Among them, Figure 6In 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.

[0271] 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.

[0272] In this embodiment, when the portions of the multiple sub-tabs 2421 welded to the first current collector 23 are stacked on the side of the first current collector 23 away from the main body 241, 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. This reduces the risk of the first current collector 23 being burned or damaged after being soldered through, and also increases the depth of the molten pool of the first solder mark 25 within the first current collector 23, thereby improving the weld reliability between the first tab 242 and the first current collector 23. This also improves 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 part 25 is set to be less than or equal to 4mm, so as to alleviate the phenomenon that the first current collector 23 occupies too much space between the first electrode 242 and the main body 241. This is beneficial to optimize the space occupied by the first electrode 242 and the first current collector 23 as a whole in the first direction X, and also helps to reduce the difficulty of bending multiple sub-electrodes 2421 toward the second direction Y and extending them to the side of the first current collector 23 away from the main body 241.

[0273] According to some embodiments of this application, see Figure 14As shown, along the first direction X, a plurality of sub-tabs 2421 are partially stacked with the first current collector 23 and the main body 241, and the first current collector 23 has a second surface 23a facing away from the main body 241, and at least a portion of the first solder mark 25 extends from the second surface 23a into the plurality of sub-tabs 2421.

[0274] In this configuration, along the first direction X, a plurality of sub-taps 2421 connected to the first solder mark 25 are stacked on the side of the first current collector 23 facing the main body 241. That is, a plurality of sub-taps 2421 are stacked and located between the first current collector 23 and the main body 241, and the portion of the plurality of sub-taps 2421 located between the first current collector 23 and the main body 241 is welded to the first current collector 23 to form the first solder mark 25. The portion of the first solder mark 25 connected to the first tab 242 is located on the side of the first current collector 23 facing the main body 241. Correspondingly, all the sub-taps 2421 of the first tab 242 are structured to extend from one side of the first current collector 23 in the second direction Y, first along the first direction X and then bend, and then extend along the second direction Y to the space between the first current collector 23 and the main body 241.

[0275] It should be noted that in the embodiment where the sub-taper 2421 includes a root region 24211 and a connecting region 24212, the root region 24211 is located on one side of the first current collector 23 in the second direction Y, and in the first direction X, the root region 24211 extends beyond the surface of the first current collector 23 facing the main body 241 in the direction pointing from the main body 241 to the first tap 242. That is, in the projection plane perpendicular to the second direction Y, at least a portion of the orthographic projection of the root region 24211 is located within the orthographic projection of the first current collector 23, so that the root region 24211 and the first current collector 23 can share a portion of the space in the first direction X, and can alleviate the phenomenon that the root region 24211 is too bent and is easily damaged or cracked during use.

[0276] The first current collector 23 has a second surface 23a facing away from the main body 241, and at least a portion of the first solder mark 25 extends from the second surface 23a into the first electrode tab 242. That is, in the first direction X, the first solder mark 25 is a structure in which at least a portion extends from the second surface 23a of the first current collector 23 facing away from the main body 241 toward the main body 241 and into the first electrode tab 242, 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 second surface 23a, and 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 second surface 23a, and 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 second surface 23a. In the projection plane of direction X, the orthographic projection of the portion where the first solder mark 25 is connected to the first tab 242 can be the structure located in the orthographic projection of the portion where the first solder mark 25 is connected to the first current collector 23. That is, when welding and assembling the first current collector 23 and the first tab 242, the welding equipment is a structure that welds and assembles the first current collector 23 and the first tab 242 from the side of the first current collector 23 away from the main body 241 in the first direction X, so that the first solder mark 25 is a structure that first passes through the entire first current collector 23 and then extends into the first tab 242.

[0277] 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 second surface 23a, or a structure in which part of the first solder mark 25 protrudes from the second surface 23a.

[0278] In this embodiment, by stacking multiple sub-tabs 2421 and the portion welded to the first current collector 23 on the side of the first current collector 23 facing the main body 241, and by having at least a portion of the first solder mark 25 extending from the second surface 23a of the first current collector 23 into the first tab 242, the first current collector 23 is partially located on the side of the first tab 242 away from the main body 241, and the first current collector 23 and the first tab 242 are welded and assembled in the first direction X from the side of the first current collector 23 away from the first tab 242. The battery cell 20 with this structure, on the one hand, welds and assembles the first current collector... When component 23 and the first electrode tab 242 are connected, the tooling fixture can be configured such that multiple sub-electrode tabs 2421 are pressed down and welded by the first current collector component 23. This ensures that the sub-electrode tabs 2421 are always pressed down by the first current collector component 23 during the welding and assembly process. This reduces the risk of local warping or cracking of the sub-electrode tabs 2421 during the welding and assembly process, and also reduces the welding gap between multiple sub-electrode tabs 2421 to reduce the risk of incomplete welding. This is beneficial to improving the welding quality between the first current collector component 23 and the first electrode tab 242. On the other hand, it can reduce the welding difficulty between the first electrode tab 242 and the first current collector component 23 after the bending is smoothed.

[0279] According to some embodiments of this application, in embodiments where multiple sub-tabs 2421 are welded to the first current collector 23 and are stacked between the first current collector 23 and the main body 241, see [link to embodiment]. Figure 14 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 0.2mm-4mm.

[0280] Among them, Figure 14 In this configuration, the thickness of the area where the first current collector 23 is connected to the first solder joint 25 is T2. For example, the thickness T2 of the area where the first current collector 23 is connected to the first solder joint 25 can be 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, etc. The values ​​are any one of the following: mm, 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, or any range between two of these values.

[0281] It should be noted that in embodiments where multiple sub-tabs 2421 are partially stacked between the first current collector 23 and the main body 241, since the first solder mark 25 needs to pass through the first current collector 23 before connecting to the first tab 242, the thickness of the area where the first current collector 23 and the first solder mark 25 are connected can be set to be smaller. In some embodiments, the thickness of the area where the first current collector 23 and the first solder mark 25 are connected can be 0.3mm-1mm.

[0282] In this embodiment, when the portions of the multiple sub-tabs 2421 welded to the first current collector 23 are stacked on the side of the first current collector 23 facing the main body 241, 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 0.2 mm to improve the structural strength of the first current collector 23. This can alleviate the deformation or warping of the first current collector 23 caused by the clamping or pressing of the tooling fixture during the welding and assembly process, thereby reducing the gap between the first current collector 23 and the first tab 242. The welding gaps generated between multiple sub-tabs 2421 during the welding assembly process help reduce the risk of incomplete welding. On the other hand, setting the thickness of the area where the first current collector 23 is connected to the first solder mark 25 to less than or equal to 4mm helps alleviate the phenomenon that the first current collector 23 occupies too much space in the first direction X, which helps improve the internal space utilization of the battery cell 20 and reduces the difficulty of the first solder mark 25 passing through the first current collector 23 and then connecting to the first tab 242, which helps reduce the welding difficulty between the first current collector 23 and the first tab 242.

[0283] According to some embodiments of this application, in conjunction with Figure 8 and Figure 9 As shown or in combination Figure 9 and Figure 14 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.

[0284] 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.

[0285] 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 L, which satisfies 5mm≤L≤40mm.

[0286] 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.

[0287] 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 2421 towards the second direction Y and extending them to one side of the first current collector 23 in the first direction X. It also reduces the difficulty of stacking and welding multiple sub-electrode 2421 with the first current collector 23 after bending. Furthermore, it helps to increase the area where the sub-electrode 2421 can be stacked and welded with the first current collector 23 after bending. On the other hand, since the multiple sub-electrode 2421 of the first electrode segment 242 are connected to the first electrode segment 2411a, the extension dimension of the sub-electrode 2421 is greater than or equal to 5mm. Before welding and assembling, the current collector components 23 are not fixed to each other, which allows multiple sub-tabs 2421 to have relative movement and lateral movement during the smoothing and bending process of 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, so as 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.

[0288] 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.

[0289] 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.

[0290] 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.

[0291] 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.

[0292] 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.

[0293] 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.

[0294] According to some embodiments of this application, refer to Figure 5 Please refer to further details. Figure 15 As shown, Figure 15 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 third surface 221, and at least a portion of the second solder mark 26 extends from the third surface 221 into the first current collector 23.

[0295] The third surface 221 is a part of the outer surface of the first electrode terminal 22 facing away from the main body 241, so that the third surface 221 is also a part of the outer surface of the first electrode terminal 22 facing the outer side of the outer shell 21.

[0296] At least a portion of the second solder mark 26 extends from the third 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 third 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 third 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 third surface 221 of the first electrode terminal 22 is located and then extends into the first current collector 23.

[0297] 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 third 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 third surface 221, and the second solder mark 26 extends through the entire first electrode terminal 22.

[0298] 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 third surface 221, or it can be that part of the second solder mark 26 protrudes from the third surface 221.

[0299] 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 third 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 flattened, 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.

[0300] 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.

[0301] 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.

[0302] 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.

[0303] In some embodiments, combined with Figure 5 and Figure 15 As shown, the first electrode terminal 22 has a fifth surface 223 facing the main body portion 241 in the first direction X. The fifth surface 223 is disposed opposite to the third surface 221, and the second solder mark portion 26 passes through the fifth surface 223. In the projection plane perpendicular to the first direction X, the orthographic projection of the fifth surface 223 does not overlap with the orthographic projection of the first electrode tab 242.

[0304] The fifth 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 fifth surface 223 is disposed opposite to the third surface 221, and the second solder mark 26 passes through the fifth surface 223. That is, the portion of the first electrode terminal 22 located between the third surface 221 and the fifth 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 fifth 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 third surface 221 and the fifth surface 223 in the first direction X.

[0305] In the projection plane perpendicular to the first direction X, the orthographic projection of the fifth 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 fifth surface 223 and the orthographic projection of the first tab 242 do not have overlapping parts, so that the fifth surface 223 and the first tab 242 are not correspondingly set in the first direction X, and the two are misaligned structures.

[0306] Optionally, in an embodiment where the orthographic projection of the fifth 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.

[0307] It should be noted that in an embodiment where the orthographic projection of the fifth 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.

[0308] In this embodiment, by setting the orthographic projection of the fifth 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.

[0309] 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.

[0310] 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.

[0311] 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.

[0312] 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.

[0313] In some embodiments, refer to Figure 16 , Figure 17 as well as Figure 18 As shown, Figure 16 This is an exploded view of the structure of a battery cell 20 provided in some embodiments of this application. Figure 17 This is a partial cross-sectional view of the battery cell 20 in some embodiments of the present application, perpendicular to a third direction Z. Figure 18 The battery cell 20 provided in some embodiments of this application is shown in a partial cross-sectional view perpendicular to the second direction Y in other embodiments. In a projection plane perpendicular to the 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. That is, in a 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, and correspondingly, at least a portion of the first tab 242 is disposed corresponding to the second solder mark 26 in the first direction X.

[0314] It should be noted that in embodiments where at least a portion of the orthographic projection of the second solder mark 26 in the projection plane perpendicular to the first direction X is located within the orthographic projection of the first tab 242 in the projection plane perpendicular to the first direction X, the first solder mark 25 and the second solder mark 26 can be interconnected or spaced apart.

[0315] 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.

[0316] In some embodiments, see Figure 17 As shown, the first solder mark 25 and the second solder mark 26 have the same structure, that is, the first solder mark 25 is the second solder mark 26. In other words, the first solder mark 25 and the second solder mark 26 are interconnected and form the same solder mark.

[0317] In embodiments where the portions of the plurality of sub-tabs 2421 of the first electrode tab 242 welded to the first current collector 23 are located between the first current collector 23 and the first electrode terminal 22 (e.g.) Figure 17 As shown), the overall structure formed by the interconnection of the first solder mark 25 and the second solder mark 26 is a structure that passes sequentially through the first electrode terminal 22 and the first tab 242 in the first direction X and extends into the first current collector 23; if the portion of the plurality of sub-tabs 2421 of the first tab 242 that are soldered to the first current collector 23 is located between the first current collector 23 and the main body 241 (e.g.) Figure 14 As shown), 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 current collector 23 in the first direction X and extends into the first tab 242.

[0318] It should be noted that in embodiments where the first solder mark 25 and the second solder mark 26 are of the same structure, the structure is such that the first electrode terminal 22, the first current collector 23 and the first tab 242 are soldered simultaneously.

[0319] In this embodiment, 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 third surface 221 of the first electrode terminal 22 away from the main body 241 into the first current collector 23 and the first tab 242, 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 welded together. Using this structure, the battery cell 20 can optimize the manufacturing process, improve production efficiency, and reduce the welding cost of the first current collector 23. On the one hand, it can reduce the range of the heat-affected zone formed by the high temperature, and on the other hand, it can shorten the current path between the first electrode terminal 22 and the first tab 242 to improve the current flow effect between the first electrode terminal 22 and the first tab 242. Furthermore, during the welding and assembly of 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 simultaneously press down or cooperate to squeeze the first tab 242, which helps to reduce the internal gap of the first tab 242, thereby reducing the risk of poor welding and improving the welding quality between the first tab 242 and the first current collector 23.

[0320] In some embodiments, combined with Figure 14 and Figure 18 As shown, along the first direction X, a plurality of sub-tabs 2421 connected to the first solder mark 25 are stacked on the side of the first current collector 23 facing the main body 241, and the first solder mark 25 and the second solder mark 26 are spaced apart.

[0321] The first current collector 23 is a structure disposed between the first electrode terminal 22 and the first tab 242 in the first direction X. Correspondingly, the first solder mark 25 and the second solder mark 26 can be disposed at intervals, that is, the first solder mark 25 and the second solder mark 26 are arranged at intervals without contacting each other. In other words, the portion of the first solder mark 25 located in the first current collector 23 and the portion of the second solder mark 26 located in the first current collector 23 are disposed at intervals. It should be noted that in an embodiment where the portions of multiple sub-tabs 2421 connected to the first solder mark 25 are stacked on the side of the first current collector 23 away from the main body 241, and at least a portion of the orthographic projection of the second solder mark 26 in a projection plane perpendicular to the first direction X is located within the orthographic projection of the first tab 242 in a projection plane perpendicular to the first direction X, then the second solder mark 26 can only first pass through the portion of the multiple sub-tabs 2421 stacked between the first current collector 23 and the first electrode terminal 22 before extending into the first current collector 23. Correspondingly, in this embodiment, the first solder mark 25 and the second solder mark 26 can only be of the same structure.

[0322] As an example, in a projection plane perpendicular to the first direction X, the orthographic projections of the first solder mark 25 and the second solder mark 26 are spaced apart.

[0323] It should be noted that in the embodiment where the first solder mark 25 and the second solder mark 26 are spaced apart, in the first direction X, the thickness of the portion of the second solder mark 26 extending into the first current collector 23 can be 0.25-0.75 of the thickness of the first current collector 23.

[0324] In this embodiment, the portions of multiple sub-tabs 2421 connected to the first solder mark 25 are stacked between the first current collector 23 and the main body 241. By setting the first solder mark 25 and the second solder mark 26 in a spaced-apart configuration, the welding assembly between the first tab 242 and the first current collector 23 and the welding assembly between the first current collector 23 and the first electrode terminal 22 can be performed separately. This reduces the welding power required during the forming process of the first solder mark 25 and the second solder mark 26, thereby reducing the forming difficulty of the first solder mark 25 and the second solder mark 26. It also reduces the influence of the molten pool between the first solder mark 25 and the second solder mark 26, which is beneficial to improving the welding quality between the first tab 242 and the first current collector 23, and also beneficial to improving the welding quality between the first current collector 23 and the first electrode terminal 22.

[0325] In some embodiments, see Figure 5 , Figure 15 , Figure 17 and Figure 18As 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 third surface 221.

[0326] 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.

[0327] The bottom surface of the groove 222 is the third 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.

[0328] 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 third 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.

[0329] In some embodiments, please continue to see Figure 5 , Figure 15 , Figure 17 and Figure 18 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.

[0330] 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 third 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.

[0331] As an example, see Figure 15 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.

[0332] 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.

[0333] 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.

[0334] According to some embodiments of this application, please refer to Figure 19 , Figure 20 , Figure 21 , Figure 22 and Figure 23 As shown, Figure 19 This is an exploded view of the structure of a battery cell 20 provided in other embodiments of this application. Figure 20 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 21 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 22This 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 23 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 fourth surface 2242 facing the main body portion 241 in a first direction X. The first side surface 2241 surrounds and connects to the fourth surface 2242. The first current collector 23 includes an interconnected tab connecting portion 231 and a terminal connecting portion 232. Along the first direction X, portions of a plurality of sub-tabs 2421 of the first tab 242 are partially stacked on one side of the tab connecting portion 231 and welded to the tab connecting portion 231. The terminal connecting portion 232 extends in a direction away from the main body portion 241 and is welded to the first side surface 2241 to form a second solder mark 26.

[0335] 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.

[0336] 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 fourth 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 fourth 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 fourth surface 2242.

[0337] 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.

[0338] 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 fourth 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.

[0339] 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.

[0340] 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.

[0341] In some embodiments, combined with Figure 20 and Figure 23 As shown, the first connecting portion 224 has a sixth surface 2243 facing the first wall 21a in the first direction X. A first side surface 2241 surrounds the sixth surface 2243, and the two ends of the first side surface 2241 in the first direction X are respectively connected to the fourth surface 2242 and the sixth surface 2243. In the first direction X, the terminal connecting portion 232 does not extend beyond the sixth surface 2243 in the direction from the main body portion 241 toward the first wall 21a.

[0342] The sixth 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 sixth surface 2243, and the two ends of the first side surface 2241 in the first direction X are respectively connected to the fourth surface 2242 and the sixth surface 2243.

[0343] In the first direction X, the terminal connection portion 232 does not extend beyond the sixth 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 sixth surface 2243.

[0344] 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 sixth 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.

[0345] In some embodiments, see Figure 20 , Figure 22 and Figure 23 As shown, the terminal connection portion 232 is welded to the first side surface 2241 to form a second solder mark portion 26. The terminal connection portion 232 has a seventh 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 seventh surface 2321 into the first connection portion 224.

[0346] The seventh surface 2321 is the surface of the terminal connection portion 232 that is away from the first connection portion 224 in the thickness direction.

[0347] At least a portion of the second solder mark 26 extends from the seventh 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 extends at least partially from the seventh surface 2321 of the terminal connecting portion 232 away from the first connecting portion 224 towards the first connecting portion 224 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 seventh 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.

[0348] 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 seventh surface 2321, or it may be that part of the second solder mark 26 protrudes from the seventh surface 2321.

[0349] 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.

[0350] In this embodiment, by configuring at least a portion of the second solder mark 26 to extend from the seventh 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 seventh 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.

[0351] According to some embodiments of this application, please refer to Figure 24 , Figure 25 , Figure 26 and Figure 27 , Figure 24 Exploded views of the structure of the battery cell 20 provided in some embodiments of this application are also included. Figure 25 This application also provides partial cross-sectional views of the battery cell 20 perpendicular to a third direction Z in some embodiments. Figure 26 This application also provides partial cross-sectional views of the battery cell 20 after the electrode assembly 24 and the first current collector 23 are assembled together, according to some embodiments. Figure 27 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, a plurality of sub-tabs 2421 of the first tab 242 are partially stacked on one side of the tab connection portion 231 and welded to the tab connection portion 231, 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.

[0352] 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 first tab 242 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. Correspondingly, the bend... The fold 233 is the part of the first current collector 23 that is bent and connects the tab connection part 231 and the terminal connection part 232. It should be noted that the first current collector 23 can be bent to form the fold 233 structure after the first tab 242 and the first electrode terminal 22 are welded and assembled. That is, the terminal connection part 232, the fold 233 and the tab connection part 231 are connected in sequence and integrally formed. The terminal connection part 232, the fold 233 and the tab connection part 231 are formed by bending the same base material.

[0353] It should be noted that in the embodiment where the first current collector 23 includes a terminal connection portion 232, a bending portion 233, and an electrode connection portion 231 connected in sequence, and the terminal connection portion 232 is located on the side of the electrode connection portion 231 facing the first electrode terminal 22 in the first direction X, the portion of the plurality of sub-electrodes 2421 connected to the first soldering portion 25 can be a structure stacked between the electrode connection portion 231 and the terminal connection portion 232, or it can be a structure stacked on the side of the electrode connection portion 231 facing the main body portion 241.

[0354] 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.

[0355] In some embodiments, refer to Figure 26 and Figure 27 Please refer to further details. Figure 28 As shown, Figure 28 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 structure, and the thickness of the bent portion 233 is 0.5mm-2mm.

[0356] The first current collector 23 is a single-layer foil structure, that is, the first current collector 23 is a structure formed by bending a single layer of metal sheet.

[0357] exist Figure 28In 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.

[0358] For example, the material of the first current collector 23 may be aluminum, aluminum alloy or copper, etc.

[0359] In this embodiment, the first current collector 23 is a single-layer foil 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 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 bent portion 233.

[0360] In some embodiments, see Figure 27 and Figure 28 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.

[0361] As an example, in Figure 28 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.

[0362] As an example, in Figure 28 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.

[0363] 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 with a single-layer foil 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, so that the terminal connection portion 232 and the bending portion 233 are of equal thickness, the difficulty of stamping and cutting the substrate of the first current collector 23 with a single-layer foil 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.

[0364] In some embodiments, the first current collector 23 may also be other structures, such as those described above. Figure 27 Please refer to further details. Figure 29 As shown, Figure 29 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 includes a plurality of foils 23b, which are stacked and connected, and the thickness of each foil 23b at the portion located in the bent portion 233 is 0.05mm-0.1mm.

[0365] The first current collector 23 includes multiple foils 23b, which are stacked and connected. In other words, the first current collector 23 is a structure formed by stacking and connecting multiple foils 23b and then bending them.

[0366] Optionally, the connection structure between the multiple foils 23b of the first current collector 23 can be various, such as abutment or adhesion. Of course, in some embodiments, the multiple foils 23b of the first current collector 23 can also be interlocked, for example, multiple foils 23b are stacked and then a groove is punched on one side of each foil 23b, so that the foil 23b has a groove on one side and a protrusion on the other side corresponding to the groove. In two adjacent foils 23b, the protrusion of one foil 23b is interlocked with the groove of another foil 23b to achieve interlocking of multiple foils. Of course, in other embodiments, the multiple foils 23b of the first current collector 23 can also be welded together, such as by ultrasonic welding.

[0367] exist Figure 29 In this embodiment, the thickness of the portion of a single foil 23b 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 23b 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.

[0368] For example, the number of foils 23b stacked in the first current collector 23 can be two, three, four, five, six, seven, eight or more.

[0369] In this embodiment, the first current collector 23 is a structure formed by stacking and connecting multiple foil sheets 23b, 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 23b located in the bending section 233 is set to be greater than or equal to 0.05 mm to improve the structural strength of the portion of foil 23b located in the bending section 233. This helps to alleviate phenomena such as breakage or cracking of foil 23b during the bending process of the bending section 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 23b located in the bending section 233 is set to be less than or equal to 0.1 mm to reduce the deformation resistance of a single foil 23b. This reduces the difficulty of bending the bending section 233 of the first current collector 23, so that the first current collector 23 can be bent to form the bending section 233 after the first tab 242 and the first electrode terminal 22 are welded together.

[0370] In some embodiments, see Figure 29As shown, the sum of the thicknesses of the portions of the multiple foils 23b located at the bending portion 233 is 0.5mm-2mm.

[0371] The sum of the thicknesses of the portions of the multiple foils 23b 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 23b within the bending portion 233. If all the foils 23b within the bending portion 233 are tightly bonded together, then the sum of the thicknesses of the portions of the multiple foils 23b located in the bending portion 233 is also the thickness of the bending portion 233 of the first current collector 23.

[0372] exist Figure 29 In this configuration, the sum of the thicknesses of the portions of the plurality of foils 23b located at the bend 233 is T5, i.e., 0.5mm ≤ T5 ≤ 2mm. Correspondingly, the first current collector 23 includes at least five foils 23b stacked together. For example, the sum of the thicknesses T5 of the portions of the plurality of foils 23b located at the bend 233 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.

[0373] In this embodiment, on the one hand, the sum of the thicknesses of the portions of the multiple foils 23b 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 23b 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.

[0374] In some embodiments, combined with Figure 27 and Figure 29 As shown, the thickness of the foil 23b at the tab connection portion 231 is greater than or equal to the thickness of the foil 23b at the bend portion 233. And / or, the thickness of the foil 23b at the terminal connection portion 232 is greater than or equal to the thickness of the foil 23b at the bend portion 233.

[0375] As an example, in this embodiment of the application, the thickness of the portion of foil 23b located at the tab connection portion 231 is equal to the thickness of the portion of foil 23b located at the bend portion 233. Of course, in other embodiments, the thickness of the portion of foil 23b located at the tab connection portion 231 may also be greater than the thickness of the portion of foil 23b located at the bend portion 233.

[0376] As an example, in this embodiment of the application, the thickness of the portion of foil 23b located at the terminal connection portion 232 is equal to the thickness of the portion of foil 23b located at the bending portion 233. Of course, in other embodiments, the thickness of the portion of foil 23b located at the terminal connection portion 232 may also be greater than the thickness of the portion of foil 23b located at the bending portion 233.

[0377] In this embodiment, by setting the thickness of the portion of foil 23b located at the tab connection 231 to be equal to the thickness of the portion of foil 23b located at the bend 233, the portions of foil 23b located at the tab connection 231 and the bend 233 are of equal thickness, thereby reducing the difficulty of stamping and cutting individual foils 23b. By setting the thickness of the portion of foil 23b located at the tab connection 231 to be greater than the thickness of the portion of foil 23b located at the bend 233, the thickness of the area of ​​foil 23b used for welding with the first tab 242 is increased while reducing the deformation resistance of the portion of foil 23b located at the bend 233. 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 23b located at the terminal connection portion 232 to be equal to the thickness of the portion of foil 23b located at the bending portion 233, the portion of foil 23b located at the terminal connection portion 232 and the portion of foil 23b located at the bending portion 233 are of equal thickness, thereby reducing the difficulty of stamping and cutting individual foils 23b. By setting the thickness of the portion of foil 23b located at the terminal connection portion 232 to be greater than the thickness of the portion of foil 23b located at the bending portion 233, the thickness of the area of ​​foil 23b used for welding with the first electrode terminal 22 can be increased while reducing the deformation resistance of the portion of foil 23b 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.

[0378] In some embodiments, see Figure 28As 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.

[0379] 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.

[0380] 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.

[0381] In some embodiments, refer to Figure 25 and Figure 27 Please refer to further details. Figure 30 , Figure 30 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. The terminal connection portion 232 is welded to the first electrode terminal 22 to form a second solder mark portion 26. Along the first direction X, the terminal connection portion 232 has an eighth 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 eighth surface 2322 into the first electrode terminal 22.

[0382] The eighth 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.

[0383] Along the first direction X, at least a portion of the second solder mark 26 extends from the eighth 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 extends from the eighth surface 2322 on the side of the terminal connection portion 232 facing the tab connection portion 231 towards the first electrode terminal 22 and into the first electrode terminal 22. This results in the second solder mark 26 being connected to the eighth surface 2322 on the outer surface of the first electrode terminal 22 away from it in the first direction X, and 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.

[0384] 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 eighth surface 2322, or a structure in which part of the second solder mark 26 protrudes from the eighth surface 2322.

[0385] In this embodiment, by setting at least a portion of the second solder mark 26 to extend from the eighth 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.

[0386] According to some embodiments of this application, in embodiments where the first electrode terminal 22 is disposed on the first wall 21a, the battery cell 20 may also have other structures, for example, please refer to Figure 31 As shown, Figure 31The image shows an exploded view of the battery cell 20 provided in some embodiments of this application in other embodiments. The electrode assembly 24 includes 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. The first direction X, the second direction Y, and the third direction Z are mutually perpendicular. 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.

[0387] 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.

[0388] As an example, in Figure 31 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.

[0389] 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.

[0390] 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.

[0391] 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.

[0392] 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.

[0393] 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.

[0394] According to some embodiments of this application, in conjunction with Figure 6 and Figure 8 And please combine further Figure 32 , Figure 33 , Figure 34 , Figure 35 and Figure 36 As shown, Figure 32 This is a schematic diagram of the structure of a battery cell 20 provided in some other embodiments of this application. Figure 33 This is an exploded view of the structure of a battery cell 20 provided in some other embodiments of this application. Figure 34 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 35 This is a partial structural diagram of the battery cell 20 provided in some other embodiments of this application. Figure 36This 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, and the first direction X, the second direction Y, and the third direction Z are perpendicular to each other. The first current collector 23 includes 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. A plurality of sub-electrodes 2421 of the first electrode tab 242 are partially stacked on one side of the electrode tab connection portion 231 and welded to the electrode tab connection portion 231. 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.

[0395] 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.

[0396] 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 a plurality of 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, such 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.

[0397] 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.

[0398] 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.

[0399] In some embodiments, see Figure 36 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.

[0400] 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.

[0401] 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.

[0402] 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.

[0403] 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.

[0404] According to some embodiments of this application, see Figure 35 and Figure 36 As shown, the tab connection portion 231 has at least one clearance notch 2311 on at least one side 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 tab 242, and along the first direction X, a plurality of sub-tabs 2421 of each first tab 242 pass through a clearance notch 2311 and extend to one side of the tab connection portion 231.

[0405] In this embodiment, the clearance notch 2311 on the tab connection portion 231 is located 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. In an embodiment where multiple sub-tabs 2421 are partially stacked on the side of the first current collector 23 away from the main body 241, at least a portion of the sub-tabs 2421 of each first tab 242 passes through a clearance notch 2311 in the first direction X and then bends around the tab connection portion 231. That is, in an embodiment where the sub-tab 2421 includes a root region 24211 and a connecting region 24212, the root region 24211 passes through the clearance notch 2311 in the first direction X. In an embodiment where the portion welded to the first current collector 23 is stacked on the side of the first current collector 23 facing the main body 241, at least a portion of the sub-taper 2421 of each first electrode 242 is inserted into the clearance notch 2311 along the first direction X, then bent and extended along the first direction X to the space between the first current collector 23 and the main body 241. That is, in an embodiment where the sub-taper 2421 includes a root region 24211 and a connecting region 24212, the root region 24211 is inserted into the clearance notch 2311 along the first direction X.

[0406] 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.

[0407] For example, in Figure 35 and Figure 36 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.

[0408] 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.

[0409] 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 inserting at least a portion of the sub-tabs 2421 of the first tab 242, on the one hand, it is convenient for the bent portion of the first tab 242 to be inserted into the clearance notch 2311 or for the first tab 242 to bend towards the second direction Y to one side of the tab connection portion 231 in the first direction X after passing through the clearance notch 2311, 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 bend 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.

[0410] According to some embodiments of this application, refer to Figure 36 Please refer to further details. Figure 37 As shown, Figure 37 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.

[0411] 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.

[0412] As an example, the mounting hole 2323 is a circular hole, and correspondingly, the insertion part 227 is cylindrical.

[0413] 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.

[0414] In some embodiments, see Figure 37 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.

[0415] 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.

[0416] 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.

[0417] In some embodiments, please continue to see Figure 37 As 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.

[0418] 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.

[0419] 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.

[0420] According to some embodiments of this application, see Figure 33 , Figure 34 and Figure 35 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.

[0421] 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.

[0422] 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.

[0423] 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.

[0424] 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.

[0425] According to some embodiments of this application, see Figure 31 as well as Figure 33 and Figure 35 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. The first direction X, the second direction Y and the third direction Z are perpendicular to each other.

[0426] 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.

[0427] As an example, in Figure 31 and Figure 33In 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.

[0428] 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.

[0429] In some embodiments, see Figure 31 as well as Figure 35 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.

[0430] 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 ...

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. The second direction 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; Multiple sub-electrode tabs are bent toward the second direction, and portions of the multiple sub-electrode tabs are stacked on one side of the first current collector in the first direction and welded to the first current collector. Each sub-electrode tab has a connection end connected to the first pole segment. 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-electrode tabs.

2. The battery cell according to claim 1, characterized in that, The sub-electrode includes a root region and a connection region located on one side of the first current collector in the first direction. The root region connects the first electrode segment and the connection region, and the connection region is welded to the first current collector. The root region is located on one side of the first collector in the first direction, and in a projection plane perpendicular to the first direction, a portion of the orthographic projection of the root region is located within the orthographic projection of the first collector.

3. The battery cell according to claim 2, characterized in that, The first electrode segment includes a first current collector and a coating layer disposed on at least one side of the first current collector. Along the first direction, the root region is connected to one end of the first current collector near the first wall, and a portion of the coating layer extends onto the root region. In a projection plane perpendicular to the first direction, at least a portion of the orthographic projection of the region where the coating layer is disposed in the root region lies within the orthographic projection of the first current collector.

4. The battery cell according to claim 1, characterized in that, The plurality of said sub-electrode tabs are welded to the first current collector to form at least one first solder mark, each of the first solder marks passing through at least part of the sub-electrode tab along the first direction, and two adjacent sub-electrode tabs are fixedly connected only through the first solder mark.

5. The battery cell according to claim 4, characterized in that, Along the first direction, at least one of the first solder marks passes through all of the sub-tabs in the first tab.

6. The battery cell according to claim 4, 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°.

7. The battery cell according to claim 6, 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.

8. The battery cell according to claim 7, characterized in that, Along the third direction, the minimum distance between two adjacent first solder marks is 1mm-10mm.

9. The battery cell according to claim 7, characterized in that, Each of the said sub-tabs is fixedly connected to at least two of the first solder pads.

10. The battery cell according to claim 6, 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.

11. The battery cell according to claim 4, 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.

12. The battery cell according to claim 4, characterized in that, The battery cell also includes: A heat insulation element is disposed, at least partially, between the first solder mark portion and the main body portion in the first direction.

13. The battery cell according to claim 12, 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.

14. The battery cell according to claim 12, characterized in that, The heat insulation component is made of insulating material.

15. The battery cell according to claim 4, characterized in that, The battery cell also includes: A support member is supported between the first solder mark portion 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.

16. The battery cell according to claim 4, characterized in that, Along the first direction, a plurality of the sub-tabs are partially welded to the first current collector and stacked on the side of the first current collector away from the main body. The first tab has a first surface away from the main body, and at least a portion of the first solder mark extends from the first surface into the first current collector.

17. The battery cell according to claim 16, characterized in that, Along the first direction, the sub-electrode gradually moves away from the main body from one end connected to the first electrode segment to the position connected to the first solder mark.

18. The battery cell according to claim 16, 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.

19. The battery cell according to claim 16, 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.

20. The battery cell according to claim 4, characterized in that, Along the first direction, a plurality of the sub-tabs are partially welded to the first current collector and are stacked between the first current collector and the main body. The first current collector has a second surface facing away from the main body, and at least a portion of the first solder mark extends from the second surface into the plurality of sub-tabs.

21. The battery cell according to claim 20, 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 0.2mm-4mm.

22. 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.

23. The battery cell according to any one of claims 1-22, 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.

24. The battery cell according to claim 23, characterized in that, Along the first direction, the outer surface of the first electrode terminal opposite to the main body includes a third surface, and at least a portion of the second solder mark extends from the third surface into the first current collector.

25. The battery cell according to claim 23, 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 fourth surface facing the main body in the first direction, the first side surface surrounding the fourth surface and being connected to the fourth surface; The first current collector includes an interconnected tab connection portion and a terminal connection portion. Along the first direction, portions of a plurality of the sub-tabs of the first tab are stacked on one side of the tab connection portion and welded to the tab connection portion. The terminal connection portion extends in a direction away from the main body portion and is welded to the first side to form the second solder mark portion.

26. The battery cell according to claim 23, 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, portions of a plurality of the sub-tabs of the first electrode tab are stacked on one side of the electrode tab connection portion and welded to the electrode tab connection portion, and the terminal connection portion is located on the side of the electrode tab connection portion facing the first electrode terminal and welded to the first electrode terminal to form the second solder mark portion.

27. The battery cell according to claim 23, 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. 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.

28. The battery cell according to any one of claims 1-22, 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 portion and the first wall in the first direction, and portions of a plurality of the sub-tabs of the first tab are stacked on one side of the tab connection portion and welded to the tab connection portion. The terminal connection portion is disposed between the main body portion and the second wall in the third direction and welded to the first electrode terminal to form a second solder mark portion.

29. The battery cell according to claim 28, 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.

30. The battery cell according to claim 28, characterized in that, The tab connection portion has 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 electrode tab. Along the first direction, multiple sub-electrodes of each first electrode tab pass through one of the clearance notches and extend to one side of the electrode tab connection portion.

31. The battery cell according to claim 28, 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.

32. The battery cell according to claim 31, 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.

33. The battery cell according to claim 31, characterized in that, The second solder mark is arranged around the plug portion.

34. The battery cell according to claim 28, 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.

35. The battery cell according to any one of claims 1-22, 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. The first direction, the second direction and the third direction are perpendicular to each other.

36. The battery cell according to claim 35, 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.

37. The battery cell according to any one of claims 1-22, characterized in that, The electrode assembly has a wound structure, has a flat region, and includes a first electrode and a second electrode with opposite polarities. The first electrode includes a plurality of first electrode segments located in the flat region and stacked along the second direction. The electrode assembly includes only one first electrode tab; or 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. The first direction, the second direction and the third direction are perpendicular to each other.

38. The battery cell according to any one of claims 1-22, 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 plate is a first electrode segment. 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. In the second direction, the bending direction of the sub-electrode of one first electrode is opposite to the bending direction of the sub-electrode of another first electrode. Each first electrode segment is connected to the sub-electrode at the end near the first wall in the first direction. The first direction, the second direction and the third direction are perpendicular to each other.

39. A battery device, characterized in that, Includes the battery cell as described in any one of claims 1-38.

40. An electrical device, characterized in that, Includes a battery cell as described in any one of claims 1-38, the battery cell being used to provide electrical energy.

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