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 component 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 first direction, the first tab comprises a plurality of sub-tabs, the sub-tabs are connected to one end of the first pole segments close to a wall part, the sub-tabs are bent towards the first direction, and parts of the plurality of sub-tabs are stacked along the thickness direction of the wall part. The first current collecting component comprises a terminal connecting part, a bending part and a tab connecting part connected in sequence, the terminal connecting part is welded with the first electrode terminal, the tab connecting part is stacked with the first tab and welded to form a first welding mark part, the first welding mark part passes through at least part of the sub-tabs, and only the first welding mark part is used to fixedly connect two adjacent sub-tabs, so that the damage of the sub-tabs is reduced, and the assembly difficulty of the first current collecting component and the first electrode terminal is reduced.

Description

Technical Field

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

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

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

[0004] This application provides a battery cell, a battery device, and an electrical device, which can effectively improve the stability and reliability 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 wall portion; the first electrode terminal is disposed in the wall portion; the electrode assembly is disposed within the casing, the electrode assembly including a main body portion and a first tab, the main body portion including a plurality of first electrode segments stacked along a first direction and having the same polarity, the first tab including a plurality of sub-tabs stacked, each of the sub-tabs of each first tab being connected to one end of a first electrode segment near the wall portion, the sub-tabs being bent toward the first direction, and portions of the plurality of sub-tabs being stacked along the thickness direction of the wall portion. The first direction is perpendicular to the thickness direction of the wall portion; the first current collector is located between the main body portion and the first electrode terminal, and 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 in the thickness direction of the wall portion and is welded to the first electrode terminal. The electrode tab connection portion and a portion of the first electrode tab are stacked and welded together along the thickness direction of the wall portion to form at least one first solder mark portion. Each first solder mark portion passes through at least a portion of the sub-electrode tab along the thickness direction of the wall portion, and two adjacent sub-electrode tabs are fixedly connected only through the first solder mark portion.

[0006] In the above technical solution, the first electrode ear includes multiple sub-electrodes stacked together. The sub-electrodes are bent toward a first direction, and portions of the multiple sub-electrodes are stacked along the thickness direction of the wall and welded to the electrode ear connection portion of the first current collector to form a first solder mark, thereby realizing the assembly connection between the first electrode ear and the first current collector. Each first solder mark is a structure that passes through at least a portion of the sub-electrodes along the thickness direction of the wall, and two adjacent sub-electrodes are fixedly connected only through the first solder mark. This ensures that after the first electrode ear is bent toward the first direction and before the first electrode ear and the electrode ear connection portion are stacked and welded, the multiple sub-electrodes of the first electrode ear are not fixedly connected or pre-welded, so as to facilitate the pre-assembly of the multiple sub-electrodes of the first electrode ear. After the first electrode tab is flattened and bent, the first electrode tab and the electrode tab connection part are welded and assembled. This allows multiple sub-electrodes to move and shift relative to each other during the flattening and bending process. This enables each sub-electrode tab to adapt to the length changes caused by the bending process, reducing local stress concentration or local bulging of the sub-electrodes during the flattening and bending process. This effectively improves the welding quality between the first electrode tab and the first current collector and effectively alleviates the phenomenon of cracking or breakage of the sub-electrodes during assembly or use. This reduces the risk of unstable connection and connection failure between the first electrode tab and the first current collector during use, which is conducive to improving the stability and reliability of the battery cell. Furthermore, because 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 electrode tab connection portion, the first current collector is configured to include a terminal connection portion, a bent 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 the thickness direction of the wall portion, so that the terminal connection portion, the bent portion, and the electrode tab connection portion are connected in sequence to form a U-shaped structure. The first current collector with this structure can first connect the unfolded first current collector with the first electrode tab and the first electrode tab. After all electrode terminals are welded, the first current collector is bent to form a bent section. Then, the electrode assembly and other components are assembled into the housing. This facilitates welding and assembling the terminal connection and the first electrode terminal from one side of the first current collector, which effectively reduces the welding difficulty between the first current collector and the first electrode terminal. It also allows the weld marks formed by the welding of the first electrode terminal and the terminal connection to be built into the housing, thereby reducing the risk of rust at the welded position of the first electrode terminal and the terminal connection during use, and reducing the risk of leakage of battery cells at the welded position of the first electrode terminal and the terminal connection.

[0007] In some embodiments, the first current collector is a single-layer foil structure, and the thickness of the bent portion is 0.5mm-2mm.

[0008] In the above technical solution, the first current collector is a single-layer foil structure. On the one hand, the thickness of the bent part of the first current collector is set to be greater than or equal to 0.5 mm to improve the structural strength of the bent part. This helps to alleviate the phenomenon of breakage or cracking of the bent part during the bending process or during use, thereby improving the stability and service life of the first current collector and reducing the risk of unstable connection or connection failure of the electrode assembly and the first electrode terminal during use. On the other hand, the thickness of the bent part of the first current collector is set to be less than or equal to 2 mm to reduce the deformation resistance of the bent part. This reduces the difficulty of bending the bent part of the first current collector, so that the unfolded first current collector is welded to the first tab and the first electrode terminal before bending the first current collector to form the bent part.

[0009] In some embodiments, the thickness of the tab connection portion is greater than or equal to the thickness of the bend portion; and / or, the thickness of the terminal connection portion is greater than or equal to the thickness of the bend portion.

[0010] In the above technical solution, by setting the thickness of the tab connection portion to be equal to the thickness of the bending portion, the tab connection portion and the bending portion are made to have the same thickness, thereby reducing the difficulty of stamping and cutting the substrate of the first current collector with a single-layer foil structure. By setting the thickness of the tab connection portion to be greater than the thickness of the bending portion, the thickness of the area of ​​the first current collector used for welding with the first tab can be increased while reducing the deformation resistance of the bending portion. This reduces the difficulty of bending the bending portion of the first current collector and increases the weld penetration of the tab connection portion, thereby improving the weld reliability between the tab connection portion and the first tab. Similarly, by setting the thickness of the terminal connection portion to be equal to the thickness of the bending portion, the terminal connection portion and the bending portion are made to have the same thickness, thereby reducing the difficulty of stamping and cutting the substrate of the first current collector with a single-layer foil structure. By setting the thickness of the terminal connection portion to be greater than that of the bending portion, the thickness of the area of ​​the first current collector used for welding with the first electrode terminal can be increased while reducing the deformation resistance of the bending portion. This reduces the difficulty of bending the bending portion of the first current collector and increases the welding penetration of the terminal connection portion, thereby improving the welding reliability between the terminal connection portion and the first electrode terminal.

[0011] In some embodiments, the first current collector includes a plurality of foils, which are stacked and connected together, and the thickness of the portion of each foil located at the bend is 0.05 mm to 0.1 mm.

[0012] In the above technical solution, the first current collector is a structure formed by stacking and connecting multiple foil sheets. This allows for meeting the welding penetration requirements of the first current collector while reducing the difficulty of bending the bent portion. Specifically, on one hand, the thickness of the foil sheet at the bent portion is set to be greater than or equal to 0.05 mm to improve the structural strength of this portion. This helps mitigate breakage or cracking of the foil sheet during bending or use, thereby improving the stability and service life of the first current collector and reducing the risk of unstable or failed connections between the electrode assembly and the first electrode terminal. On the other hand, the thickness of the foil sheet at the bent portion is set to be less than or equal to 0.1 mm to reduce the deformation resistance of a single foil sheet. This reduces the difficulty of bending the bent portion of the first current collector, allowing the unfolded first current collector to be welded to the first tab and the first electrode terminal before bending the first current collector to form the bent portion.

[0013] In some embodiments, the sum of the thicknesses of the portions of the plurality of foils located at the bend is 0.5 mm to 2 mm.

[0014] In the above technical solution, on the one hand, the sum of the thicknesses of the portions of the multiple foils located in the bending section is set to be greater than or equal to 0.5 mm to improve the overall structural strength of the bending section. This helps to alleviate phenomena such as breakage or cracking of the bending section during bending or use, thereby improving the stability and service life of the first current collector and reducing the risk of unstable connection or connection failure of the electrode assembly and the first electrode terminal during use. On the other hand, the sum of the thicknesses of the portions of the multiple foils located in the bending section is set to be less than or equal to 2 mm to reduce the overall deformation resistance of the bending section. This reduces the difficulty of bending the bending section of the first current collector, so that the first current collector can be bent to form the bending section after the first current collector is welded to the first tab and the first electrode terminal.

[0015] In some embodiments, the thickness of the foil portion located at the tab connection is greater than or equal to the thickness of the foil portion located at the bend; and / or, the thickness of the foil portion located at the terminal connection is greater than or equal to the thickness of the foil portion located at the bend.

[0016] In the above technical solution, by setting the thickness of the portion of the foil located at the tab connection to be equal to the thickness of the portion of the foil located at the bend, the portion of the foil located at the tab connection and the portion of the foil located at the bend are of equal thickness, thereby reducing the difficulty of stamping and cutting individual foils. By setting the thickness of the portion of the foil located at the tab connection to be greater than the thickness of the portion of the foil located at the bend, the deformation resistance of the portion of the foil located at the bend is reduced while the thickness of the area of ​​the foil used for welding with the first tab is increased. This reduces the difficulty of bending the bend of the first current collector and increases the weld penetration of the tab connection, thereby improving the weld reliability between the tab connection and the first tab. Similarly, by setting the thickness of the portion of the foil located at the terminal connection to be equal to the thickness of the portion of the foil located at the bend, the portion of the foil located at the terminal connection and the portion of the foil located at the bend are of equal thickness, thereby reducing the difficulty of stamping and cutting individual foils. By setting the thickness of the foil portion at the terminal connection to be greater than the thickness of the foil portion at the bend, the thickness of the area where the foil is used for welding with the first electrode terminal is increased while reducing the deformation resistance of the foil portion at the bend. This reduces the difficulty of bending the bend of the first current collector and increases the welding penetration of the terminal connection, thereby improving the welding reliability between the terminal connection and the first electrode terminal.

[0017] In some embodiments, the bent portion is provided with a through hole, which penetrates the bent portion along the thickness direction.

[0018] In the above technical solution, by providing through holes on the bent portion of the first current collector, the deformation resistance of the bent portion can be further reduced, thereby further reducing the difficulty of bending the bent portion of the first current collector. This makes it easier to first weld the unfolded first current collector to the first tab and the first electrode terminal before bending the first current collector to form the bent portion.

[0019] In some embodiments, the terminal connection portion is welded to the first electrode terminal to form a second solder mark portion; along the thickness direction of the wall portion, the terminal connection portion has a first surface facing away from the first electrode terminal, and at least a portion of the second solder mark portion extends from the first surface into the first electrode terminal.

[0020] In the above technical solution, by setting at least a portion of the second solder mark to extend from the first surface of the terminal connection portion into the first electrode terminal in the thickness direction of the wall portion, the welding assembly between the terminal connection portion and the first electrode terminal is such that the terminal connection portion and the first electrode terminal are welded from the side of the terminal connection portion away from the first electrode terminal. This enables 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. It also reduces the welding difficulty between the terminal connection portion and the first electrode terminal.

[0021] In some embodiments, in a projection plane perpendicular to the thickness direction of the wall portion, 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 first direction or the angle between the length direction of the orthographic projection of the first solder mark and the first direction is less than or equal to 30°.

[0022] In the above technical solution, since the multiple first electrode segments are stacked along the first direction and the sub-electrode tabs are bent towards the first 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 first direction. Before the bending, the multiple sub-electrode tabs of the first electrode tab are arranged along the first direction. After the multiple sub-electrode tabs are bent towards the first direction, by setting the orthographic projection of the first solder part in the projection plane perpendicular to the thickness direction of the wall part 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 thickness direction of the wall part is parallel to the first direction or the angle between the first solder part and the first direction is less than or equal to 30°, the first solder part can be connected to more sub-electrode tabs, thereby improving the current flow effect between the first electrode tab and the electrode tab connection part, and improving the connection stability between the first electrode tab and the electrode tab connection part.

[0023] In some embodiments, there are multiple first solder marks on the first tab, and the multiple first solder marks are arranged at intervals along the second direction, with the thickness direction of the wall portion, the first direction, and the second direction being perpendicular to each other.

[0024] 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 the second direction, the orthographic projection of the multiple first solder marks in the projection plane perpendicular to the thickness direction of the wall portion 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 tab connection portion, thereby further improving the current flow effect between the first tab and the tab connection portion, and further improving the connection stability between the first tab and the tab connection portion. 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 be connected to the tab connection portion through the remaining first solder marks, thereby improving the fault tolerance rate of the welding assembly between the sub-tab and the tab connection portion, and improving the electrical connection stability between the sub-tab and the tab connection portion, so as to reduce the risk of connection failure between the sub-tab and the tab connection portion.

[0025] In some embodiments, the plurality of sub-tabs include a plurality of first sub-tabs fixedly connected to the first solder pad, and each first sub-tab is fixedly connected to at least two of the first solder pads.

[0026] In the above technical solution, by fixing each first sub-electrode tab to at least two first solder marks, each sub-electrode tab that is welded to the electrode connection part is passed through by at least two first solder marks. On the one hand, this can increase the current flow area and current flow path between the first sub-electrode tab and the electrode connection part. On the other hand, it can still be electrically connected to the electrode connection part through other first solder marks even if the connection between the first sub-electrode tab and one or part of the first solder marks fails, which is beneficial to improving the electrical connection stability between the first sub-electrode tab and the electrode connection part.

[0027] In some embodiments, in a projection plane perpendicular to the thickness direction of the wall portion, the width of the orthographic projection of the first solder mark portion in the second direction is 0.5mm-5mm, and the thickness direction of the wall portion, the first direction, and the second direction are perpendicular to each other.

[0028] 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 thickness direction of the wall in the second 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 electrode connection part, and improving the connection stability between the first electrode and the electrode connection part. On the other hand, the width of the orthographic projection of the first solder mark in the projection plane perpendicular to the thickness direction of the wall in the second 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 welding the electrode connection part and the first electrode is too large, which helps to reduce the power required for welding and assembling the electrode connection part 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.

[0029] 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.

[0030] 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 its thickness direction, so as to increase the welding area between the individual sub-electrode and the electrode connection part, thereby improving the current flow effect between the individual sub-electrode and the electrode connection part, and also improving the connection stability between the individual sub-electrode and the electrode connection part. 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 its 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, which is beneficial to reducing the welding difficulty between the individual sub-electrode and the electrode connection part, and also beneficial to reducing the power required for welding and assembling the electrode connection part and the first electrode.

[0031] In some embodiments, the plurality of sub-tabs include a plurality of first sub-tabs fixedly connected to the first solder mark portion. Along the thickness direction of the wall portion, portions of the plurality of first sub-tabs connected to the first solder mark portion are stacked on the side of the tab connection portion away from the main body portion. The first tab has a second surface away from the tab connection portion, and at least a portion of the first solder mark portion extends from the second surface into the tab connection portion.

[0032] In the above technical solution, by stacking multiple first sub-tabs connected to the first solder mark on the side of the tab connection portion away from the main body, and at least a portion of the first solder mark is a structure extending from the second surface of the first tab into the tab connection portion, the first tab is partially located on the side of the tab connection portion away from the main body, and the first tab and the tab connection portion are welded and assembled from the side of the first tab away from the tab connection portion in the thickness direction of the wall portion. Using this structure, the battery cell can achieve the first smoothing of the multiple sub-tabs of the first tab. The structure of bending the first tab and then welding the tab connection part together 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 internal short circuit of the battery cell caused by the first sub-tab being inserted into the main body. On the other hand, it reduces the welding difficulty between the first tab and the tab connection part after smoothing and bending, and facilitates the smoothing and bending of multiple sub-tabs of the first tab based on the tab connection part, thereby reducing the bending difficulty of the sub-tabs.

[0033] In some embodiments, all of the sub-tabs in the first tab are fixedly connected to the first solder mark.

[0034] In the above technical solution, by fixing all the sub-tabs in the first electrode tab to the first solder part, each sub-tab in the first electrode tab is a structure that is welded to the electrode tab connection part, thereby further improving the current flow effect and connection stability between the first electrode tab and the electrode tab connection part, and reducing the risk of excessively long current flow path or connection failure of the first electrode segment due to the sub-tabs on some first electrode segments not being welded to the electrode tab connection part.

[0035] In some embodiments, along the thickness direction of the wall portion, the thickness of the portion of the first solder mark extending into the tab connection portion is T1, and the thickness of the tab connection portion is T2, satisfying 0.25≤T1 / T2≤0.75.

[0036] In the above technical solution, on the one hand, the thickness of the portion of the first solder mark extending into the tab connection portion is set to be greater than or equal to 0.25 times the thickness of the tab connection portion, so as to improve the welding penetration of the first solder mark in the tab connection portion, thereby improving the current flow effect between the first tab and the tab connection portion, and improving the connection stability between the first tab and the tab connection portion. On the other hand, the thickness of the portion of the first solder mark extending into the tab connection portion is set to be less than or equal to 0.75 times the thickness of the tab connection portion, so as to reduce the risk of the tab connection portion being burned through and damaging other components.

[0037] 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.

[0038] In the above technical solution, when multiple first sub-electrode tabs connected to the first solder mark are stacked on the side of the electrode tab connection portion away from the main body, on the one hand, the extension dimension of the sub-electrode 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-electrode tabs in the first direction and extending them to the side of the electrode tab connection portion away from the main body, and also reduces the difficulty of stacking and welding multiple sub-electrode tabs with the electrode tab connection portion after bending. It also helps to increase the area where the sub-electrode tabs can be stacked and welded with the electrode tab connection portion after bending. On the other hand, Since the multiple sub-tabs of the first electrode are not fixed to each other before being welded and assembled with the electrode connection part, the multiple sub-tabs can move and shift relative to each other during the process of smoothing and bending the first electrode. Therefore, by setting the extension dimension of the sub-tab from one end connected to the first electrode segment to the end away from the first electrode segment to less than or equal to 40mm, the phenomenon of redundancy or local bulging of the sub-tab after bending can be effectively alleviated. This is to optimize the space occupied by the first electrode in the thickness direction of the wall, which is conducive to improving the internal space utilization of the battery cell and thus improving the energy density of the battery cell.

[0039] In some embodiments, the thickness of the tab connection portion is 0.3mm-4mm along the thickness direction of the wall portion.

[0040] In the above technical solution, when multiple first sub-tabs are stacked on the side of the tab connection portion away from the main body, the thickness of the tab connection portion in the wall thickness direction is set to be greater than or equal to 0.3 mm to reduce the risk of burns or damage to the main body after the tab connection portion is welded through. It can also increase the molten pool depth of the first solder portion in the tab connection portion to improve the welding reliability between the first tab and the tab connection portion, and also improve the structural strength of the tab connection portion. On the other hand, the thickness of the tab connection portion in the wall thickness direction is set to be less than or equal to 4 mm to alleviate the phenomenon that the tab connection portion occupies too much space between the first tab and the main body. This is beneficial to optimize the space occupied by the first tab and the tab connection portion as a whole in the wall thickness direction, and also helps to reduce the difficulty of bending multiple sub-tabs toward the first direction and extending to the side of the tab connection portion away from the main body.

[0041] In some embodiments, the first sub-taper has a connecting end connected to the first pole segment. In a projection plane perpendicular to the thickness direction of the wall portion, at least a portion of the orthographic projection of the connecting end of the first sub-taper is located within the orthographic projection of the pole tab connecting portion, and the first sub-taper with the orthographic projection of the connecting end located within the orthographic projection of the pole tab connecting portion is bent around the pole tab connecting portion.

[0042] In the above technical solution, by setting the orthographic projection of at least a portion of the first sub-tab connection end in the projection plane perpendicular to the thickness direction of the wall portion to a structure located within the orthographic projection of the tab connection portion in the projection plane perpendicular to the thickness direction of the wall portion, the portion of the at least a portion of the first sub-tab welded to the tab connection portion is a structure located between the tab connection portion and the main body portion. This portion of the first sub-tab is a structure that starts from the side of the tab connection portion facing the main body portion, bends around the tab connection portion, and extends to the side of the tab connection portion away from the main body portion. The battery cell with this structure can, on the one hand, achieve the function of separating at least a portion of the first sub-tab portion between the tab connection portion and the main body portion, thereby reducing the risk of burns or damage to the main body portion after the tab connection portion is welded through. On the other hand, it can achieve the sharing of a portion of space between the tab connection portion and the first tab in the thickness direction of the wall portion, and also achieve the sharing of a portion of space between the tab connection portion and the first tab in the first direction. This is beneficial to optimize the space occupied by the tab connection portion and the first tab as a whole, thereby improving the internal space utilization rate of the battery cell and thus improving the energy density of the battery cell.

[0043] In some embodiments, along the thickness direction of the wall portion, the portion of the first sub-taper located between the taper connection portion and the main body portion gradually moves away from the main body portion from one end connected to the first pole segment to the end away from the first pole segment.

[0044] 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 tab is bent in the first direction and before the first electrode tab and the electrode tab connection part are stacked and welded, the multiple sub-tabs of the first electrode tab are a structure that can be smoothed and bent before being welded and assembled with the electrode tab connection part. Thus, the part of the first sub-tab located between the electrode tab connection part and the main body is set to gradually move away from the main body from one end connected to the first electrode segment to the end away from the first electrode segment. This reduces the phenomenon of local bulging or swelling of the part of the first sub-tab located between the electrode tab connection part and the main body due to stress. In this way, the risk of cracking or breaking of the part of the first sub-tab located between the electrode tab connection part and the main body during assembly or use can be reduced. It can also save the space occupied by the part of the multiple first sub-tabs located between the electrode tab connection part and the main body in the thickness direction of the wall, thereby improving the energy density of the battery cell.

[0045] In some embodiments, the first sub-taper has a connection end connected to the first pole segment, and in a projection plane perpendicular to the thickness direction of the wall portion, the orthographic projection of the pole tab connection portion does not overlap with the orthographic projection of the connection ends of all the first sub-tapers.

[0046] In the above technical solution, by setting the orthographic projection of all the connecting ends of the first sub-tabs in the projection plane perpendicular to the thickness direction of the wall to a structure that does not overlap with the orthographic projection of the tab connecting portion in the projection plane perpendicular to the thickness direction of the wall, the tab connecting portion is located between the first sub-tab and the main body, and the first sub-tab is a structure that starts from one side of the tab connecting portion in the first direction, bends around the tab connecting portion, and extends to the side of the tab connecting portion away from the main body. The battery cell with this structure can reduce the difficulty of smoothing and bending the first sub-tab, and reduce the difficulty of stacking and welding multiple sub-tabs of the first tab with the tab connecting portion. On the other hand, it can realize that the tab connecting portion and the first tab share part of the space in the thickness direction of the wall, and can further optimize the dimensions of the tab connecting portion and the main body in the thickness direction of the wall, thereby saving the space occupied by the first tab and the tab connecting portion as a whole in the thickness direction of the wall, improving the internal space utilization of the battery cell, and thus improving the energy density of the battery cell.

[0047] 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 tab connection portion and the main body portion in the thickness direction of the wall portion, and at least a portion of the orthographic projection of the first solder mark portion is located within the orthographic projection of the heat insulation component in a projection plane perpendicular to the thickness direction of the wall portion.

[0048] In the above technical solution, by setting at least a portion of the heat insulation component in the thickness direction of the wall portion as a structure located between the tab connection portion and the main body portion, and setting at least a portion of the orthographic projection of the first solder mark portion in the projection plane perpendicular to the thickness direction of the wall portion as a structure located within the orthographic projection of the heat insulation component in the projection plane perpendicular to the thickness direction of the wall portion, the first solder mark portion is located on the side of the heat insulation component away from the main body portion in the thickness direction of the wall portion, thereby enabling the heat insulation component to play a heat insulation role between the first solder mark portion and the main body portion, thereby reducing the phenomenon of burning the main body portion and other components during the welding connection of the tab connection portion and the first tab to form the first solder mark portion, and improving the assembly quality of the battery cell.

[0049] In some embodiments, in a projection plane perpendicular to the thickness direction of the wall portion, the orthographic projection of the first solder mark portion is entirely located within the orthographic projection of the heat insulation member.

[0050] In the above technical solution, by setting the entire orthographic projection of the first solder mark in the projection plane perpendicular to the thickness direction of the wall portion as a structure located within the orthographic projection of the heat insulation component in the projection plane perpendicular to the thickness direction of the wall portion, the heat insulation effect of the heat insulation component between the first solder mark and the main body portion is further improved. This further reduces the phenomenon of the electrode connection portion and the first electrode ear burning the main body portion and other components during the welding connection and formation of the first solder mark portion, thereby further improving the assembly quality of the battery cell.

[0051] In some embodiments, the heat insulation element is made of an insulating material.

[0052] 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 role between the tab connection part and the main body part, thereby reducing the risk of short circuit between the tab connection part and the main body part during use and improving the reliability of the battery cell.

[0053] In some embodiments, the heat insulation member is attached to the surface of the tab connection portion facing the main body portion.

[0054] In the above technical solution, by setting the heat insulation component as a structure connected to the surface of the electrode connecting part facing the main body, on the one hand, the heat insulation component can be assembled together with the electrode connecting part between the first electrode and the main body, which helps to reduce the difficulty of setting the heat insulation component between the electrode connecting part and the main body and optimizes the production cycle. On the other hand, it can improve the stability and reliability of the heat insulation component set between the electrode connecting part and the main body, which helps to reduce the risk of the heat insulation component falling off between the electrode connecting part and the main body during the welding process between the electrode connecting part and the first electrode.

[0055] In some embodiments, the battery cell further includes a support member; the support member is supported between the tab connection portion and the main body portion along the thickness direction of the wall portion, 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 thickness direction of the wall portion.

[0056] In the above technical solution, by providing a support member between the electrode tab connection and the main body, and at least a portion of the orthographic projection of the first solder mark in the projection plane perpendicular to the thickness direction of the wall is located within the orthographic projection of the support member in the projection plane perpendicular to the thickness direction of the wall, the support member can provide support and stability for the electrode tab connection, thereby reducing the welding gap between the first electrode tab and the electrode tab connection, and reducing the shaking phenomenon of the electrode tab connection during welding assembly, thus reducing the risk of incomplete welding between the first electrode tab and the electrode tab connection, and improving the welding quality of the first electrode tab and the electrode tab connection.

[0057] In some embodiments, the plurality of sub-tabs include a plurality of first sub-tabs fixedly connected to the first solder mark portion. Along the thickness direction of the wall portion, portions of the plurality of first sub-tabs connected to the first solder mark portion are stacked on the side of the tab connection portion facing the main body portion. The tab connection portion has a third surface facing away from the main body portion, and at least a portion of the first solder mark portion extends from the third surface into the first tab.

[0058] In the above technical solution, by stacking multiple first sub-tabs connected to the first solder mark on the side of the tab connection portion facing the main body, and at least a portion of the first solder mark is a structure that extends from the third surface of the tab connection portion into the first tab, the tab connection portion is at least partially located on the side of the first tab away from the main body and welded to the tab connection portion and the first tab in the thickness direction of the wall portion. With this structure, the battery cell can achieve the following when welding the tab connection portion and the first tab: the tooling fixture can be a structure that presses down multiple first sub-tabs through the tab connection portion and welds them. This ensures that the first sub-tabs are always pressed down by the tab connection portion during the welding assembly process, thereby reducing the risk of local warping or cracking of the first sub-tabs during the welding assembly process, and reducing the welding gap between multiple first sub-tabs to reduce the risk of incomplete welding, which is beneficial to improving the welding quality between the tab connection portion and the first tab. On the other hand, it can reduce the welding difficulty between the first tab and the tab connection portion after smoothing and bending.

[0059] In some embodiments, in the bending direction of the first sub-taper, at least one of the plurality of sub-tapers located on one side of the plurality of first sub-tapers bends around the tab connection and extends to the side of the tab connection opposite to the main body.

[0060] In the above technical solution, by setting at least one of the multiple sub-taps that is not connected to the first solder mark and is located on one side of the multiple first sub-taps in the bending direction of the first sub-taps as a structure that bends around the tab connection and extends to the side of the tab connection away from the main body, the overall regularity of the first tab is improved, which helps to alleviate the phenomenon that some sub-taps located in the edge area of ​​the multiple sub-taps are redundantly occupying space or are inserted upside down into the main body.

[0061] In some embodiments, all the sub-tabs in the first electrode tab are fixedly connected to the first solder mark portion, and all the sub-tabs in the first electrode tab are located on the side of the electrode tab connection portion facing the main body portion in the thickness direction of the wall portion.

[0062] In the above technical solution, by setting all the sub-taps in the first electrode tab on the side of the electrode tab connection portion facing the main body and welding them to the electrode tab connection portion, it is possible to reduce the waste of sub-taps in the first electrode tab and reduce manufacturing costs. On the other hand, it is possible to alleviate the problem of redundant space occupied by sub-taps due to not being welded to the electrode tab connection portion.

[0063] In some embodiments, within the same first electrode tab, a plurality of the sub-electrodes arranged sequentially from the first to the nth along the bending direction of the first sub-electrode tab are all first sub-electrodes, where n is greater than or equal to 2.

[0064] In the above technical solution, by setting multiple sub-electrodes arranged sequentially from the first to the nth along the bending direction of the first sub-electrode in the same first electrode tab as first sub-electrodes, and by welding multiple sub-electrodes arranged sequentially from the first one along the bending direction of the first sub-electrode to the electrode tab connection part, the welding range between the electrode tab connection part and the first electrode tab can be increased, and the first solder joint can be fixedly connected to more sub-electrodes, thereby improving the connection stability and overcurrent effect between the electrode tab connection part and the first electrode tab.

[0065] In some embodiments, the first sub-taper has a connection end connected to the first pole segment, and in a projection plane perpendicular to the thickness direction of the wall portion, at least a portion of the orthographic projection of the connection end of the first sub-taper is located within the orthographic projection of the pole segment connection portion.

[0066] In the above technical solution, by setting the orthographic projection of at least a portion of the first sub-tab connection end in the projection plane perpendicular to the thickness direction of the wall portion to a structure located within the orthographic projection of the tab connection portion in the projection plane perpendicular to the thickness direction of the wall portion, the first sub-tab portion has more or even the entire structure located between the tab connection portion and the main body portion. The battery cell with this structure can, on the one hand, improve the separation effect of the first tab between the tab connection portion and the main body portion, thereby reducing the risk of burning or damaging the main body portion during the welding and assembly process of the tab connection portion and the first tab portion. On the other hand, it can optimize the overall layout of the tab connection portion and the first tab portion, thereby improving the internal space utilization rate of the battery cell and helping to improve the energy density of the battery cell.

[0067] 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.

[0068] In the above technical solution, when multiple first sub-electrode tabs connected to the first solder joint are stacked on the side of the electrode tab connection portion facing the main body, on the one hand, the extension dimension of the sub-electrode 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, so as to reduce the difficulty of bending multiple sub-electrode tabs in the first direction, and can also reduce the difficulty of stacking and welding multiple sub-electrode tabs with the electrode tab connection portion after bending, and also helps to increase the area where the sub-electrode tabs can be stacked and welded with the electrode tab connection portion after bending. On the other hand, due to the first electrode tabs The multiple sub-tabs are not fixed to each other before being welded and assembled with the tab connection part. This allows the multiple sub-tabs to have the ability to move and shift relative to each other during the smoothing and bending process of the first tab. By setting the extension dimension of the sub-tab from one end connected to the first electrode segment to the end away from the first electrode segment to less than or equal to 40mm, the phenomenon of redundancy or local bulging of the sub-tab after bending can be effectively alleviated. This is to optimize the space occupied by the first tab in the thickness direction of the wall, which is conducive to improving the internal space utilization of the battery cell and thus improving the energy density of the battery cell.

[0069] In some embodiments, the thickness of the tab connection portion is 0.2mm-4mm along the thickness direction of the wall portion.

[0070] In the above technical solution, when multiple first sub-tabs are stacked on the side of the tab connection portion facing the main body, the thickness of the tab connection portion in the wall thickness direction is set to be greater than or equal to 0.2mm to improve the structural strength of the tab connection portion. This can alleviate the phenomenon of deformation or warping of the tab connection portion caused by the clamping or pressing of the tooling fixture during the welding assembly process, thereby reducing the welding gap between the tab connection portion and the first tab and between multiple first 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 tab connection portion in the wall thickness direction is set to be less than or equal to 4mm to alleviate the phenomenon of the tab connection portion occupying too much space in the wall thickness direction, which is beneficial to improving the internal space utilization of the battery cell and reducing the difficulty of the first soldering portion passing through the tab connection portion before connecting to the first tab, which is beneficial to reducing the welding difficulty between the tab connection portion and the first tab.

[0071] 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 wall and are spaced apart along the second direction. The plurality of first tabs are all welded to the tab connection portion to form the first solder mark portion. The thickness direction of the wall, the first direction and the second direction are perpendicular to each other.

[0072] In the above technical solution, by providing multiple first tabs of the same polarity arranged at intervals along the second direction at one end of the main body facing the wall, and by welding the multiple first tabs to the tab connection part 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 tab connection part, thereby improving the current flow effect between the main body and the tab connection part; on the other hand, when some of the first tabs have unstable connection or connection failure between them and the tab connection part, the remaining first tabs can still achieve electrical connection between the main body and the tab connection part, thereby effectively improving the stability and service life of the battery cell.

[0073] In some embodiments, the tab connection portion is connected to the bending portion in the region corresponding to the first electrode terminal in the thickness direction of the wall portion, and the bending portion is connected to one end of the tab connection portion in the first direction.

[0074] In the above technical solution, by connecting the bent portion to one end of the area corresponding to the tab connection portion and the first electrode terminal in the first direction, the interference between the bent portion and the multiple first tabs arranged in the second direction can be reduced. On the other hand, the forming difficulty of the tab connection portion, the bent portion and the terminal connection portion of the first current collector can be reduced, thereby reducing the manufacturing difficulty of the battery cell. Furthermore, the size of the bent portion from the end connected to the tab connection portion to the end connected to the terminal connection portion can be optimized, thereby saving the manufacturing materials and manufacturing cost of the first current collector.

[0075] In some embodiments, along the second direction, at least one of the plurality of first tabs is located on one side of the first electrode terminal, and at least one of the first tabs is located on the other side of the first electrode terminal.

[0076] In the above technical solution, a portion of the first tabs are located on one side of the first electrode terminal in the second direction, and another portion of the first tabs are located on the other side of the first electrode terminal in the second direction. This results in the first electrode terminal having first tabs on both sides in the second direction, and the first electrode terminal being located between two adjacent first tabs in the second direction. The battery cell with this structure can optimize the layout between the first electrode terminal and the multiple first tabs, and enable the first electrode terminal and the first tabs to share space in the thickness direction of the wall. On the other hand, it enables the multiple first tabs to be a structure that guides the flow from the two sides of the first electrode terminal in the second direction through the tab connection, thereby shortening the flow 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 required flow area of ​​the tab connection, thus optimizing the thickness of the tab connection.

[0077] In some embodiments, along the second direction, the minimum distance between the first tab located on one side of the first electrode terminal and the first tab located on the other side of the first electrode terminal is 20mm-50mm.

[0078] In the above technical solution, on the one hand, the minimum distance between the two first electrodes located on both sides of the first electrode terminal and adjacent to the first electrode terminal in the second direction is set to be greater than or equal to 20mm, so as to facilitate the placement of the first electrode terminal between the two adjacent first electrodes and reduce the interference between the first electrode terminal and the first electrodes. On the other hand, the minimum distance between the two first electrodes located on both sides of the first electrode terminal and adjacent to the first electrode terminal in the second direction is set to be less than or equal to 50mm, so as to save the space occupied by the two first electrodes adjacent to the first electrode terminal in the second direction, thereby optimizing the spatial layout of multiple first electrodes in the second direction.

[0079] In some embodiments, each of the plurality of sub-tabs of the first electrode tab includes a plurality of first sub-tabs fixedly connected to the first solder mark portion. Along the thickness direction of the wall portion, the portions of the plurality of first sub-tabs connected to the first solder mark portion are stacked on one side of the electrode tab connection portion. In the first direction, the bending direction of the first sub-tab of one first electrode tab is opposite to the bending direction of the first sub-tab of another first electrode tab.

[0080] In the above technical solution, by setting the bending direction of the first sub-taper of one first electrode tab in the first direction and the bending direction of the first sub-taper of another first electrode tab in the first direction to be opposite, the smoothing bending directions of at least two first electrodes tabs are opposite. The battery cell with this structure can achieve a structure in which the stacking order of the multiple first sub-tapers of at least two first electrodes tabs and the electrode tab connection parts are opposite. Since the multiple first electrodes tabs and the electrode tab connection parts are all welded and assembled on the same side, even if the first sub-taper of each first electrode tab near the welding side is damaged, the damaged first sub-taper of the two first electrodes tabs with opposite smoothing bending directions can be the first sub-taper connected to different first electrode segments. Thus, at least one first sub-taper of the multiple first sub-tapers connected to the first electrode segment is not damaged, and 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.

[0081] In some embodiments, the electrode assembly is a stacked structure, the main body includes a plurality of first electrode plates and a plurality of second electrode plates, the first electrode plates and the second electrode plates have opposite polarities, and the first electrode plates and the second electrode plates are alternately and stacked along the first direction; the first electrode plate is a first electrode segment, and each first electrode segment is connected to a first sub-electrode tab at one end near the wall in the thickness direction of the wall.

[0082] In the above technical solution, the electrode assembly has a stacked structure, so that the first electrode of the main body is a whole first electrode segment. Thus, by connecting at least one first sub-electrode to each first electrode segment, each first electrode of the main body can be electrically connected to the first current collector, thereby reducing the risk of failure of some first electrodes of the electrode assembly. In the structure where the flattening and bending directions of at least two first electrodes are opposite, it is convenient for the electrode connection part to be welded to different first electrodes, so that at least one sub-electrode on each first electrode segment can be welded to the first current collector, which helps to reduce the difficulty of setting a first sub-electrode on each first electrode segment.

[0083] Secondly, embodiments of this application also provide a battery device, including the aforementioned battery cell.

[0084] 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

[0085] 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.

[0086] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments; Figure 2 Exploded views of the structure of the battery device provided in some embodiments of this application; Figure 3 This is a schematic diagram of the structure of a battery cell provided in some embodiments of this application; Figure 4 Exploded views of the structure of a single battery cell provided in some embodiments of this application; Figure 5 Partial cross-sectional view of a battery cell provided in 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 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 8 Structural view of the first current collector of a battery cell provided in some embodiments of this application; Figure 9 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 thickness direction of the wall portion; Figure 10 A cross-sectional view of the main body of the electrode assembly of a battery cell provided in some embodiments of this application, perpendicular to the thickness direction of the wall portion in other embodiments; Figure 11 A partial cross-sectional view of the first current collector of a battery cell provided in some embodiments of this application, perpendicular to the second direction; Figure 12 A partial cross-sectional view of the bent portion of the first current collector of a battery cell provided in some embodiments of this application; Figure 13 A cross-sectional view of a battery cell after the first current collector and the first electrode terminal are assembled together, according to some embodiments of this application; Figure 14 A front view of the electrode assembly of a battery cell provided in some embodiments of this application after the first tab and the tab connection portion are welded and assembled in the thickness direction of the wall portion; Figure 15A partial cross-sectional view of the electrode assembly and the tab connection of the first current collector of a battery cell provided in some embodiments of this application after they are assembled together; Figure 16 A partial cross-sectional view of the electrode assembly and the tab connection of the first current collector of a battery cell provided in other embodiments of this application after they are assembled together; Figure 17 Exploded views of the battery cell structure are also provided in some embodiments of this application; Figure 18 This application also provides schematic diagrams of the electrode assembly structure of a battery cell in some embodiments; Figure 19 This application also provides a front view of the electrode assembly of a battery cell in a first direction according to some embodiments; Figure 20 This application also provides a schematic diagram of the structure of the first current collector of a battery cell in some embodiments.

[0087] Icons: 1000 - Vehicle; 100 - Battery assembly; 10 - Housing; 11 - First housing body; 12 - Second housing body; 20 - Battery cell; 21 - Casing; 211 - Wall; 212 - Housing; 2121 - Opening; 213 - End cap; 22 - First electrode terminal; 23 - First current collector; 23a - Foil; 231 - Terminal connection; 2311 - First surface; 232 - Bending portion; 2321 - Through hole; 233 - Electrode connection; 233a - Third surface; 2331 - First connection area; 2332 - Second connection area; 24 - Electrode assembly; 241 - Main body; 241a - Straight area; 241b - Bending area; 2411 - First electrode; 2411a - First electrode Segment; 2411b-First bending segment; 2412-Second electrode plate; 2412a-Second electrode segment; 2412b-Second bending segment; 2413-Isolator; 242-First electrode tab; 2421-Sub-electrode tab; 2421a-Soldering area; 24211-First sub-electrode tab; 24211a-Connecting end; 24212-Second sub-electrode tab; 2422-Second 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; 200-Controller; 300-Motor; X-Thickness direction of the wall; Y-First direction; Z-Second direction; R-Wounding direction. Detailed Implementation

[0088] 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.

[0089] 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.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] In this application, "multiple" means two or more (including two).

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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.).

[0101] 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.

[0102] 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.

[0103] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0104] 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.).

[0105] 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.

[0106] 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.

[0107] 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.

[0108] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0109] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] Among them, the gel electrolyte includes a polymer as the electrolyte backbone network, combined with an ionic liquid - lithium salt.

[0117] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0118] 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.

[0119] 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.

[0120] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0121] In some implementations, the electrode assembly has a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0122] In some implementations, the electrode assembly has a stacked structure.

[0123] As an example, multiple positive and negative electrodes can be set, and multiple positive and multiple negative electrodes can be stacked alternately.

[0124] 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.

[0125] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0126] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0127] As an example, the separators can be continuously arranged, either by folding or rolling between any adjacent positive or negative electrode plates.

[0128] 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.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] 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.

[0134] 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.

[0135] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0136] 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.

[0137] 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.

[0138] 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.

[0139] 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.

[0140] 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.

[0141] 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 housing and an end cap that are assembled together. The electrode assembly has tabs at the end facing the end cap, and each tab includes multiple sub-tabs stacked together with the same polarity. The end cap also has electrode terminals electrically connected to the tabs of the electrode assembly. The electrode terminals are connected to the tabs via the current collector to realize the input or output of electrical energy from the battery cell. In related technologies, to reduce the difficulty of forming the tabs and assembling the current collector and the tabs, especially in prismatic battery cells, multiple sub-tabs are usually pre-welded together before being welded to the current collector. Afterwards, the current collector is assembled... After the current collector and electrode terminals are welded together, the tabs are bent to facilitate the assembly of the end cap and the housing. However, in this type of battery cell, the multiple sub-tabs are pre-welded and assembled with the current collector before bending. Since the multiple sub-tabs are pre-welded and fixed before bending, they cannot adapt to the length changes caused by bending. This can lead to local stress concentration or local arching of the sub-tabs, making them prone to cracking or breakage during assembly or use. This can result in unstable connections or connection failures during battery cell use, which is detrimental to improving the stability and reliability of the battery cell.

[0142] Based on the above considerations, in order to solve the problem of low stability and reliability of battery cells, this application provides a battery cell including a casing, a first electrode terminal, a first current collector, and at least one electrode assembly. The casing has a wall portion. The first electrode terminal is disposed in the wall portion. The electrode assembly is disposed inside the casing and includes a main body portion and a first tab. The main body portion includes a plurality of first electrode segments stacked along a first 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 wall portion. The sub-tabs are bent toward the first direction, and portions of the plurality of sub-tabs are stacked along the thickness direction of the wall portion. The first direction is perpendicular to the thickness direction of the wall portion. The first current collector is located between the main body and the first electrode terminal. The first current collector includes a terminal connection part, a bending part and an electrode tab connection part connected in sequence. The terminal connection part is located on the side of the electrode tab connection part facing the first electrode terminal in the thickness direction of the wall and is welded to the first electrode terminal. The electrode tab connection part and the portion of the first electrode tab are stacked and welded together in the thickness direction of the wall to form at least one first solder mark. Each first solder mark passes through at least a portion of the sub-electrode tab in the thickness direction of the wall, and two adjacent sub-electrode tabs are fixedly connected only through the first solder mark.

[0143] In this type of battery cell, the first tab includes multiple sub-tabs stacked together. The sub-tabs are bent towards a first direction, and portions of the multiple sub-tabs are stacked along the thickness direction of the wall and welded to the tab connection portion of the first current collector to form a first solder mark. This achieves the assembly connection between the first tab and the first current collector. Each first solder mark is a structure that passes through at least a portion of the sub-tab along the thickness direction of the wall, and adjacent sub-tabs are fixedly connected only through the first solder mark. This ensures that the multiple sub-tabs of the first tab are not fixedly connected or pre-welded after the first tab is bent towards the first direction and before the first tab and the tab connection portion are stacked and welded, allowing for the prior assembly of the multiple sub-tabs of the first tab. After smoothing and bending, the first tab and the tab connection are welded together. This allows multiple sub-tabs to move and shift relative to each other during the smoothing and bending process. Each sub-tab can adapt to the length changes caused by bending, reducing local stress concentration or bulging. This effectively improves the welding quality between the first tab and the first current collector and mitigates cracking or breakage of the sub-tabs during assembly or use. It also reduces the risk of unstable connection and connection failure between the first tab and the first current collector during use, thus improving the stability and reliability of the battery cell. Furthermore, because the gap between the first current collector and the main body is too small after the first tab is smoothed, bent, and welded to the tab connection portion, the first current collector is configured to include a terminal connection portion, a bent portion, and a tab connection portion connected in sequence. The terminal connection portion is located on the side of the tab connection portion facing the first electrode terminal and is welded to the first electrode terminal. The tab connection portion and portions of the first tab are stacked and welded together along the thickness direction of the wall portion, forming a U-shaped structure where the terminal connection portion, bent portion, and tab connection portion are connected in sequence. The first current collector with this structure... The first current collector component can be welded to the first tab and the first electrode terminal before bending the first current collector component to form a bent part. Then, the electrode assembly and other components are assembled into the housing. This facilitates welding and assembling the terminal connection part and the first electrode terminal from one side of the first current collector component, thereby effectively reducing the welding difficulty between the first current collector component and the first electrode terminal. It also allows the second solder mark to be built into the housing, reducing the risk of rusting of the second solder mark during use and the risk of leakage of battery cells at the location of the second solder mark.

[0144] The battery cells disclosed in this application can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft. A power system for such an electrical device can be constructed using battery cells and battery devices disclosed in this application. This helps to alleviate the problem of unstable or failed connections that easily occur during the use of battery cells, thereby improving the stability and reliability of battery cell usage.

[0145] 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.

[0146] 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.

[0147] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of this application. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery device 100 is installed inside the vehicle 1000. The battery device 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to supply power to the vehicle 1000; for example, the battery device 100 can serve as the operating power source or general power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 controls the battery device 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during startup, navigation, and driving.

[0148] 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.

[0149] 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.

[0150] 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.

[0151] 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.

[0152] 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.

[0153] 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.

[0154] 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.

[0155] 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 and Figure 9 , 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. 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 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 8 This is a structural view of the first current collector 23 of the battery cell 20 provided in some embodiments of this application. Figure 9 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 thickness direction X of the wall portion. 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 wall portion 211. The first electrode terminal 22 is disposed on the wall portion 211. Electrode assembly 24 is disposed inside housing 21. Electrode assembly 24 includes main body 241 and first electrode tab 242. Main body 241 includes a plurality of first electrode segments 2411a stacked along the first direction Y and having the same polarity. First electrode tab 242 includes a plurality of sub-electrode tabs 2421 stacked. Each sub-electrode tab 2421 of each first electrode tab 242 is connected to one end of a first electrode segment 2411a near the wall 211. Sub-electrode tabs 2421 are bent toward the first direction Y and portions of the plurality of sub-electrode tabs 2421 are stacked along the thickness direction X of the wall. The first direction Y is perpendicular to the thickness direction X of the wall. The first current collector 23 is located between the main body 241 and the first electrode terminal 22. The first current collector 23 includes a terminal connection portion 231, a bending portion 232 and an electrode tab connection portion 233 connected in sequence. The terminal connection portion 231 is located on the side of the electrode tab connection portion 233 facing the first electrode terminal 22 in the thickness direction X of the wall and is welded to the first electrode terminal 22. The electrode tab connection portion 233 and a portion of the first electrode tab 242 are stacked and welded together in the thickness direction X of the wall to form at least one first solder mark portion 25. Each first solder mark portion 25 passes through at least a portion of the sub-electrode tab 2421 in the thickness direction X of the wall, and two adjacent sub-electrode tabs 2421 are fixedly connected only through the first solder mark portion 25.

[0156] 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.

[0157] 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.

[0158] Optionally, the housing 21 may include a housing 212 and an end cap 213. The housing 212 has an internal cavity for accommodating the electrode assembly 24 and has an opening 2121. That is, the housing 212 is a hollow structure with an opening 2121 at one end. The end cap 213 covers the opening 2121 of the housing 212 and forms a sealed connection to form a sealed space for accommodating the electrode assembly 24 and the electrolyte.

[0159] The housing 212 includes a bottom wall and a side wall. The bottom wall is disposed opposite to the end cap 213. 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 2121.

[0160] It should be noted that the wall portion 211 used to house the first electrode terminal 22 can be the end cap 213 of the housing 21, or it can be a wall of the housing 212 of the housing 21. For example, in... Figure 3 and Figure 4 In this embodiment, the wall portion 211 is the end cap 213. Of course, the structure of the battery cell 20 is not limited to this. In other embodiments, the wall portion 211 can also be the bottom wall of the housing 212 and the end cap 213 that are disposed opposite to each other, or the wall portion 211 can also be the side wall of the housing 212 and the end cap 213 that are adjacent to each other and connected to each other.

[0161] The housing 212 can be of various shapes, such as a cuboid or prism structure. The shape of the housing 212 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 212 has a cuboid structure, and correspondingly, the end cap 213 has a rectangular plate structure.

[0162] 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 212 and two end caps 213. The housing 212 is a hollow structure with openings 2121 formed on both opposite sides. One end cap 213 is fitted onto one opening 2121 of the housing 212 and forms a sealed connection to form a sealed space for accommodating the electrode assembly 24 and the electrolyte. That is, the housing 212 has openings 2121 formed on both opposite sides, and the two end caps 213 are fitted onto both sides of the housing 212 to close the corresponding openings 2121.

[0163] 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.

[0164] 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.

[0165] 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.

[0166] 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 thickness direction X of the wall. 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 thickness direction X of the wall.

[0167] For example, the first tab 242 is connected to one end of the first electrode 2411 facing the wall 211 in the thickness direction X of the wall portion, and the second tab 243 is connected to one end of the second electrode 2412 facing the wall 211 in the thickness direction X of the wall portion.

[0168] The first electrode tab 242 of the electrode assembly 24 is a multilayer metal foil structure connected to one end of the first electrode 2411 in the thickness direction X of the wall portion. That is, the first electrode tab 242 includes a plurality of sub-electrodes 2421 stacked together, and each layer of metal foil is a sub-electrodes 2421. Similarly, the second electrode tab 243 of the electrode assembly 24 is a multilayer metal foil structure connected to one end of the second electrode 2412 in the thickness direction X of the wall portion. It should be noted that the first tab 242 and the first electrode 2411 can be separate structures. For example, the first tab 242 and the first current collector of the first electrode 2411 can be welded together. Of course, the first tab 242 and the first electrode 2411 can also be integrally formed. For example, the first current collector of the first tab 242 and the first electrode 2411 can be formed by integrally cutting the same metal foil to form the first tab 242 and the first current collector. Similarly, the second tab 243 and the second electrode 2412 can be separate structures. For example, the second tab 243 and the second current collector of the second electrode 2412 can be welded together. Of course, the second tab 243 and the second electrode 2412 can also be integrally formed. For example, the second current collector of the second tab 243 and the second electrode 2412 can be formed by integrally cutting the same metal foil to form the second tab 243 and the second current collector.

[0169] 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 wall portion 211. That is, the first electrode tab 242 is disposed at the end of the main body portion 241 facing the wall portion 211 in the thickness direction X of the wall portion. The sub-electrodes 2421 in the first electrode tab 242 are connected to the end of the corresponding first electrode segment 2411a in the thickness direction X of the wall portion near the wall portion 211. 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 portion 241 are arranged at intervals along the first direction Y. 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 one end of the main body portion 241 facing the wall portion 211 in the thickness direction X of the wall portion, and the multiple first electrode tabs 242 are arranged at intervals along the second direction Z. 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.

[0170] Sub-electrode 2421 bends toward the first direction Y, and portions of multiple sub-electrode 2421 are stacked along the thickness direction X of the wall. That is, the sub-electrode 2421 is a structure in which the extension direction from one end connected to the first pole segment 2411a to the end away from the first pole segment 2411a changes from the thickness direction X of the wall to the first direction Y. It should be noted that the sub-electrode 2421 can be a structure that bends toward the first direction Y to only one side, so that the sub-electrode 2421 includes only one bending position. Of course, the sub-electrode 2421 can also be a structure that bends toward the first direction Y to one side first and then bends toward the first direction Y to the other side, so that the sub-electrode 2421 is a continuously bent structure and includes two bending positions.

[0171] 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 9 In this structure, electrode assembly 24 has a wound structure, and the central axis of the winding of electrode assembly 24 extends along the thickness direction X of the wall portion. Correspondingly, the main body portion 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 Z. The thickness direction X, the first direction Y, and the second direction Z of the wall portion are perpendicular to each other. Of course, if electrode assembly 24 has a stacked structure, refer to... Figure 10As shown, Figure 10 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 thickness direction X of the wall portion. In this view, 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.

[0172] 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 Y. It should be noted that if the electrode assembly 24 is a wound structure, see [reference needed]. Figure 9 As 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.

[0173] 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 Y. Correspondingly, the first electrode segment 2411a is the first electrode plate 2411 and the second electrode segment 2412a is the second electrode plate 2412.

[0174] 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.

[0175] 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 4 As 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 Y. It should be noted that if the electrode assembly 24 is a stacked structure, the number of electrode assemblies 24 disposed within the casing 21 is usually one.

[0176] 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.

[0177] The first electrode terminal 22 is inserted into the first electrode lead-out hole of the wall portion 211 and is insulated and installed on the wall portion 211. That is to say, there is no electrical connection between the first electrode terminal 22 and the wall portion 211 of the outer casing 21. It should be noted that the first electrode lead-out hole is a structure that penetrates the wall portion 211 along the thickness direction X of the wall portion.

[0178] 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.

[0179] The first current collector 23 is disposed between the main body 241 and the wall portion 211, meaning that the wall portion 211, the first current collector 23, and the main body 241 are arranged sequentially along the thickness direction X of the wall portion. Correspondingly, the terminal connection portion 231 is the part of the first current collector 23 located on the side of the first electrode terminal 22 facing the main body 241 and welded to the first electrode terminal 22. The electrode tab connection portion 233 is the part of the first current collector 23 and the first electrode tab 242 stacked and welded together along the thickness direction X of the wall portion to form the first solder mark portion 25. The terminal connection portion 231 and the electrode tab connection portion 233 are stacked along the thickness direction X of the wall portion, and the terminal connection portion 231 is located between the electrode tab connection portion 233 and the first electrode terminal 22 and welded to the first electrode terminal 22. The second solder mark 26 is formed. Correspondingly, the bending part 232 is the part of the first current collector 23 that is bent and connected to the tab connection part 233 and the terminal connection part 231. It should be noted that the first current collector 23 can be bent to form the bending part 232 after it has been welded and assembled with the first tab 242 and the first electrode terminal 22. That is, the terminal connection part 231, the bending part 232 and the tab connection part 233 are connected in sequence and integrally formed. The terminal connection part 231, the bending part 232 and the tab connection part 233 are formed by bending the same substrate.

[0180] It should be noted that in the embodiment where the first current collector 23 includes a terminal connection portion 231, a bending portion 232 and an electrode connection portion 233 connected in sequence, and the terminal connection portion 231 is located on the side of the electrode connection portion 233 facing the first electrode terminal 22 in the thickness direction X of the wall portion, 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 233 and the terminal connection portion 231, or it can be a structure stacked on the side of the electrode connection portion 233 facing the main body portion 241.

[0181] The electrode connecting portion 233 and the portion of the first electrode 242 are stacked and welded together along the thickness direction X of the wall to form at least one first solder mark portion 25. That is, the portion of the first electrode 242 and the electrode connecting portion 233 are stacked on each other in the thickness direction X of the wall, and the portion of the first electrode 242 and the electrode connecting portion 233 are connected by the first solder mark portion 25. Correspondingly, the first solder mark portion 25 is the area where the portion of the first electrode 242 and the electrode connecting portion 233 are welded together to form a fused area or a solder mark area.

[0182] Each first solder mark 25 passes through at least a portion of the sub-tabs 2421 along the thickness direction X of the wall portion. That is, the portion of the first solder mark 25 located in the tab connection portion 233 and the portion of the first solder mark 25 located in the first tab 242 are arranged and connected along the thickness direction X of the wall portion. Each first solder mark 25 is fixedly connected to at least a portion of the sub-tabs 2421. Correspondingly, the first solder mark 25 can be a structure in which some sub-tabs 2421 are sequentially connected and stacked in the thickness direction X of the wall portion, or it can be a structure in which all sub-tabs 2421 are sequentially connected and stacked in the thickness direction X of the wall portion.

[0183] 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 electrode connecting part 233 and the first electrode 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.

[0184] For example, in the embodiments of this application, the first solder mark 25 is a solder mark structure formed by laser welding of the tab connection 233 and the first tab 242.

[0185] For example, the material of the first current collector 23 can also be various, such as aluminum, aluminum alloy or copper.

[0186] In this embodiment of the application, the terminal connection portion 231 and the first electrode terminal 22 of the first current collector 23 are welded together, and the terminal connection portion 231 and the first electrode terminal 22 of the first current collector 23 are welded together to form a second solder mark portion 26. For example, the second solder mark portion 26 is a solder mark structure formed by laser welding of the terminal connection portion 231 and the first electrode terminal 22 of the first current collector 23.

[0187] 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.

[0188] For example, see Figure 4 and Figure 5As shown, the second electrode terminal 27 is also provided on the wall portion 211, and the second electrode terminal 27 is arranged at intervals with the first electrode terminal 22. Correspondingly, the wall portion 211 is provided with a second electrode lead-out hole, which penetrates the wall portion 211 along the thickness direction X. The second electrode terminal 27 passes through the second electrode lead-out hole of the wall portion 211 and is insulated and installed on the wall portion 211. That is to say, no electrical connection is formed between the second electrode terminal 27 and the wall portion 211 of the outer casing 21.

[0189] 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.

[0190] 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.

[0191] For example, the material of the second current collector 28 can also be various, such as aluminum, aluminum alloy or copper.

[0192] 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.

[0193] In some embodiments, see Figure 3 and Figure 4 As shown, the battery cell 20 may also include a pressure relief component 29, which is disposed on the housing 21 and is used to release the internal pressure of the battery cell 20 when the internal pressure or temperature of the battery cell 20 reaches a predetermined value.

[0194] For example, the pressure relief component 29 is disposed on the end cap 213 of the housing 21. Of course, in other embodiments, the pressure relief component 29 may also be disposed on the housing 212 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.

[0195] In this embodiment, the first electrode tab 242 includes a plurality of sub-electrode tabs 2421 stacked together. The sub-electrode tabs 2421 are bent toward the first direction Y, and portions of the plurality of sub-electrode tabs 2421 are stacked along the thickness direction X of the wall and welded to the electrode tab connection portion 233 of the first current collector 23 to form a first solder mark portion 25, so as to realize the assembly connection between the first electrode tab 242 and the first current collector 23. Each first solder mark portion 25 is a structure that passes through at least a portion of the sub-electrode tab 2421 along the thickness direction X of the wall, and two adjacent sub-electrode tabs 2421 are fixedly connected only through the first solder mark portion 25. This means that after the first electrode tab 242 is bent toward the first direction Y and before the first electrode tab 242 is stacked and welded to the electrode tab connection portion 233, the plurality of sub-electrode tabs 2421 of the first electrode tab 242 are not fixedly connected or pre-welded, so as to facilitate the assembly connection between the first electrode tab 242 and the first current collector 233. After smoothing and bending multiple sub-tabs 2421, the first tab 242 and the tab connection 233 are welded together. This allows the multiple sub-tabs 2421 to move and shift relative to each other during the smoothing and bending process of the first tab 2422. This enables each sub-tab 2421 to adapt to the length change caused by bending during the smoothing and bending process, thereby reducing the phenomenon of local stress concentration or local bulging of the sub-tabs 2421 during the smoothing and bending process. This effectively improves the welding quality between the first tab 242 and the first current collector 23, and effectively alleviates the phenomenon of cracking or breakage of the sub-tabs 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.Furthermore, because the gap between the first current collector 23 and the main body 241 is too small after the first tab 242 is smoothed, bent, and welded to the tab connection portion 233, the first current collector 23 is configured to include a terminal connection portion 231, a bent portion 232, and a tab connection portion 233 connected in sequence. The terminal connection portion 231 is located on the side of the tab connection portion 233 facing the first electrode terminal 22 and is welded to the first electrode terminal 22. The tab connection portion 233 and portions of the first tab 242 are stacked and welded together along the thickness direction X of the wall, so that the terminal connection portion 231, the bent portion 232, and the tab connection portion 233 are connected in sequence to form a U-shaped structure. The first current collector 23 with this structure can first connect the unfolded first current collector 23 to the first electrode terminal 22. After the tab 242 and the first electrode terminal 22 are welded together, the first current collector 23 is bent to form a bent portion 232. Then, the electrode assembly 24 and other components are assembled into the housing 21. This facilitates welding and assembling the terminal connection portion 231 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 weld marks formed by the welding of the first electrode terminal 22 and the terminal connection portion 231 to be built into the housing 21, thereby reducing the risk of rust at the welding position of the first electrode terminal 22 and the terminal connection portion 231 during use, and reducing the risk of leakage of the battery cell 20 at the welding position of the first electrode terminal 22 and the terminal connection portion 231.

[0196] According to some embodiments of this application, refer to Figure 5 and Figure 8 Please refer to further details. Figure 11 As shown, Figure 11 This is a partial cross-sectional view of the first current collector 23 of the battery cell 20 provided in some embodiments of this application, perpendicular to the second direction Z. The first current collector 23 is a single-layer foil structure, and the thickness of the bent portion 232 is 0.5mm-2mm.

[0197] 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.

[0198] exist Figure 11 In the first current collector 23, the thickness of the bent portion 232 is T3, i.e., 0.5mm ≤ T3 ≤ 2mm. For example, the thickness T3 of the bent portion 232 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.

[0199] In this embodiment, the first current collector 23 is a single-layer foil structure. On the one hand, the thickness of the bent portion 232 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 232. This helps to alleviate the phenomenon of breakage or cracking of the bent portion 232 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 232 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 232. This reduces the difficulty of bending the bent portion 232 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 232.

[0200] In some embodiments, see Figure 8 and Figure 11 As shown, the thickness of the tab connection portion 233 is greater than or equal to the thickness of the bent portion 232. And / or, the thickness of the terminal connection portion 231 is greater than or equal to the thickness of the bent portion 232.

[0201] As an example, in Figure 11 In the first current collector 23 shown, the thickness of the tab connection portion 233 is equal to the thickness of the bending portion 232. Of course, in other embodiments, the thickness of the tab connection portion 233 may also be greater than the thickness of the bending portion 232.

[0202] As an example, in Figure 11 In the first current collector 23 shown, the thickness of the terminal connection portion 231 is equal to the thickness of the bending portion 232. Of course, in other embodiments, the thickness of the terminal connection portion 231 may also be greater than the thickness of the bending portion 232.

[0203] In this embodiment, by setting the thickness of the tab connection portion 233 to be equal to the thickness of the bending portion 232, the tab connection portion 233 and the bending portion 232 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 233 to be greater than the thickness of the bending portion 232, 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 232. This reduces the difficulty of bending the bending portion 232 of the first current collector 23 and increases the welding penetration of the tab connection portion 233, thereby improving the welding reliability between the tab connection portion 233 and the first tab 242. Similarly, by setting the thickness of the terminal connection portion 231 to be equal to the thickness of the bending portion 232, so that the terminal connection portion 231 and the bending portion 232 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 231 to be greater than the thickness of the bending portion 232, 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 232. This reduces the difficulty of bending the bending portion 232 of the first current collector 23 and increases the welding penetration of the terminal connection portion 231, thereby improving the welding reliability between the terminal connection portion 231 and the first electrode terminal 22.

[0204] According to some embodiments of this application, refer to Figure 8 Please refer to further details. Figure 12 As shown, Figure 12 This is a partial cross-sectional view of the bent portion 232 of the first current collector 23 of the battery cell 20 provided in some embodiments of this application. The first current collector 23 includes a plurality of foils 23a, which are stacked and connected together, and the thickness of each foil 23a at the portion located in the bent portion 232 is 0.05mm-0.1mm.

[0205] The first current collector 23 includes multiple foils 23a, which are stacked and connected. In other words, the first current collector 23 is a structure formed by stacking and connecting multiple foils 23a and then bending them.

[0206] Optionally, the connection structure between the multiple foils 23a of the first current collector 23 can be various, such as abutment or adhesion. Of course, in some embodiments, the multiple foils 23a of the first current collector 23 can also be interlocked, for example, multiple foils 23a are stacked and then a groove is punched on one side of the multiple foils 23a, so that the foil 23a has a groove on one side and a protrusion on the other side corresponding to the groove. In two adjacent foils 23a, the protrusion of one foil 23a is interlocked with the groove of another foil 23a to realize the interlocking of multiple foils. Of course, in other embodiments, the multiple foils 23a of the first current collector 23 can also be welded to each other, such as by ultrasonic welding.

[0207] exist Figure 12 In this embodiment, the thickness of the portion of a single foil 23a located at the bend 232 is T4, i.e., 0.05mm ≤ T4 ≤ 0.1mm. For example, the thickness T4 of the portion of a single foil 23a located at the bend 232 can be any one of 0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.09mm, or 0.1mm, or a range between any two.

[0208] For example, the number of foils 23a stacked in the first current collector 23 can be two, three, four, five, six, seven, eight or more.

[0209] In this embodiment, the first current collector 23 is a structure formed by stacking and connecting multiple foil sheets 23a, which can reduce the difficulty of bending the bent portion 232 of the first current collector 23 while meeting the welding penetration requirements of the first current collector 23. On the one hand, the thickness of the portion of foil 23a located in the bending portion 232 is set to be greater than or equal to 0.05 mm to improve the structural strength of the portion of foil 23a located in the bending portion 232. This helps to alleviate phenomena such as breakage or cracking of foil 23a during the bending process of the bending portion 232 or during use, thereby improving the stability and service life of the first current collector 23 and reducing the risk of unstable connection or connection failure of electrode assembly 24 and first electrode terminal 22 during use. On the other hand, the thickness of the portion of foil 23a located in the bending portion 232 is set to be less than or equal to 0.1 mm to reduce the deformation resistance of a single foil 23a. This reduces the difficulty of bending the bending portion 232 of the first current collector 23, so that the unfolded first current collector 23 is welded to the first tab 242 and the first electrode terminal 22 before bending the first current collector 23 to form the bending portion 232.

[0210] In some embodiments, see Figure 12As shown, the sum of the thicknesses of the portions of the multiple foils 23a located at the bending portion 232 is 0.5mm-2mm.

[0211] The sum of the thicknesses of the portions of the multiple foils 23a located in the bending portion 232 is also the thickness of the bending portion 232 of the first current collector 23 minus the sum of the gaps between all two adjacent foils 23a within the bending portion 232. If all the foils 23a within the bending portion 232 are tightly fitted together, then the sum of the thicknesses of the portions of the multiple foils 23a located in the bending portion 232 is also the thickness of the bending portion 232 of the first current collector 23.

[0212] exist Figure 12 In this configuration, the sum of the thicknesses of the portions of the plurality of foils 23a located at the bend 232 is T5, i.e., 0.5mm ≤ T5 ≤ 2mm. Correspondingly, the first current collector 23 includes at least five foils 23a stacked together. For example, the sum of the thicknesses T5 of the portions of the plurality of foils 23a located at the bend 232 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.

[0213] In this embodiment, on the one hand, the sum of the thicknesses of the portions of the multiple foils 23a located in the bending portion 232 is set to be greater than or equal to 0.5 mm to improve the overall structural strength of the bending portion 232. This helps to alleviate phenomena such as breakage or cracking of the bending portion 232 during bending or use, thereby improving the stability and service life of the first current collector 23 and reducing the risk of unstable connection or connection failure of the electrode assembly 24 and the first electrode terminal 22 during use. On the other hand, the sum of the thicknesses of the portions of the multiple foils 23a located in the bending portion 232 is set to be less than or equal to 2 mm to reduce the overall deformation resistance of the bending portion 232. This reduces the difficulty of bending the bending portion 232 of the first current collector 23, so that the first current collector 23 can be bent to form the bending portion 232 after the first tab 242 and the first electrode terminal 22 are welded together.

[0214] In some embodiments, combined with Figure 8 and Figure 12 As shown, the thickness of the foil 23a located at the tab connection portion 233 is greater than or equal to the thickness of the foil 23a located at the bend portion 232. And / or, the thickness of the foil 23a located at the terminal connection portion 231 is greater than or equal to the thickness of the foil 23a located at the bend portion 232.

[0215] As an example, in this embodiment of the application, the thickness of the portion of foil 23a located at the tab connection portion 233 is equal to the thickness of the portion of foil 23a located at the bend portion 232. Of course, in other embodiments, the thickness of the portion of foil 23a located at the tab connection portion 233 may also be greater than the thickness of the portion of foil 23a located at the bend portion 232.

[0216] As an example, in this embodiment of the application, the thickness of the portion of foil 23a located at the terminal connection portion 231 is equal to the thickness of the portion of foil 23a located at the bending portion 232. Of course, in other embodiments, the thickness of the portion of foil 23a located at the terminal connection portion 231 may also be greater than the thickness of the portion of foil 23a located at the bending portion 232.

[0217] In this embodiment, by setting the thickness of the portion of foil 23a located at the tab connection 233 to be equal to the thickness of the portion of foil 23a located at the bend 232, the portions of foil 23a located at the tab connection 233 and the bend 232 are of equal thickness, thereby reducing the difficulty of stamping and cutting individual foils 23a. By setting the thickness of the portion of foil 23a located at the tab connection 233 to be greater than the thickness of the portion of foil 23a located at the bend 232, the thickness of the area of ​​foil 23a used for welding with the first tab 242 is increased while reducing the deformation resistance of the portion of foil 23a located at the bend 232. This reduces the difficulty of bending the bend 232 of the first current collector 23 and increases the welding penetration of the tab connection 233, thereby improving the welding reliability between the tab connection 233 and the first tab 242. Similarly, by setting the thickness of the portion of foil 23a located at the terminal connection portion 231 to be equal to the thickness of the portion of foil 23a located at the bending portion 232, the portion of foil 23a located at the terminal connection portion 231 and the portion of foil 23a located at the bending portion 232 are of equal thickness, thereby reducing the difficulty of stamping and cutting individual foils 23a. By setting the thickness of the portion of foil 23a located at the terminal connection portion 231 to be greater than the thickness of the portion of foil 23a located at the bending portion 232, the thickness of the area of ​​foil 23a used for welding with the first electrode terminal 22 can be increased while reducing the deformation resistance of the portion of foil 23a located at the bending portion 232. This reduces the difficulty of bending the bending portion 232 of the first current collector 23 and increases the welding penetration of the terminal connection portion 231, thereby improving the welding reliability between the terminal connection portion 231 and the first electrode terminal 22.

[0218] According to some embodiments of this application, see Figure 11As shown, the bent portion 232 is provided with a through hole 2321, which penetrates the bent portion 232 along the thickness direction of the bent portion 232.

[0219] The through hole 2321 is a structure that penetrates the surfaces of both sides of the bent portion 232 in the thickness direction. Correspondingly, the number of through holes 2321 provided on the bent portion 232 can be one or more. Similarly, the shape of the cross-section of the through hole 2321 provided on the bent portion 232 can also be various, such as circular, rectangular, elliptical or elongated.

[0220] In this embodiment, by providing a through hole 2321 on the bent portion 232 of the first current collector 23, the deformation resistance of the bent portion 232 can be further reduced, thereby further reducing the difficulty of bending the bent portion 232 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 232.

[0221] According to some embodiments of this application, refer to Figure 5 and Figure 8 Please refer to further details. Figure 13 As shown, Figure 13 This is a cross-sectional view of a battery cell 20 provided in some embodiments of this application after the first current collector 23 and the first electrode terminal 22 are assembled together. The terminal connection portion 231 is welded to the first electrode terminal 22 to form a second solder mark portion 26. Along the thickness direction X of the wall portion, the terminal connection portion 231 has a first surface 2311 facing away from the first electrode terminal 22, and at least a portion of the second solder mark portion 26 extends from the first surface 2311 into the first electrode terminal 22.

[0222] The first surface 2311 is the surface of the terminal connection portion 231 facing away from the first electrode terminal 22 in the thickness direction X of the wall portion, and is also the surface of the terminal connection portion 231 facing the tab connection portion 233 in the thickness direction X of the wall portion.

[0223] Along the thickness direction X of the wall portion, at least a portion of the second solder mark 26 extends from the first surface 2311 into the first electrode terminal 22. That is, in the thickness direction X of the wall portion, the second solder mark 26 is a structure in which at least a portion extends from the first surface 2311 on the side of the terminal connection portion 231 facing the tab connection portion 233 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 first surface 2311 on the outer surface of the first electrode terminal 22 away from it in the thickness direction X of the wall portion, and in the thickness direction perpendicular to the wall portion... In the projection plane to X, 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 231. That is, when welding and assembling the terminal connection portion 231 and the first electrode terminal 22, the welding equipment is a structure that welds and assembles the terminal connection portion 231 and the first electrode terminal 22 from the side of the terminal connection portion 231 away from the first electrode terminal 22 in the thickness direction X of the wall, so that the second solder mark 26 first passes through the terminal connection portion 231 and then extends into the first electrode terminal 22.

[0224] Optionally, the outer surface of the second solder mark 26 facing away from the first electrode terminal 22 in the thickness direction X of the wall can be flush with the first surface 2311, or it can be a structure in which part of the second solder mark 26 protrudes from the first surface 2311.

[0225] In this embodiment, by configuring at least a portion of the second solder mark 26 to extend from the first surface 2311 of the terminal connection portion 231 into the first electrode terminal 22 in the thickness direction X of the wall portion, the welding assembly between the terminal connection portion 231 and the first electrode terminal 22 is configured such that the terminal connection portion 231 and the first electrode terminal 22 are welded from the side of the terminal connection portion 231 away from the first electrode terminal 22. This enables 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 231 and the first electrode terminal 22.

[0226] According to some embodiments of this application, refer to Figure 6 Please refer to further details. Figure 14 As shown, Figure 14This is a front view of the electrode assembly 24 of the battery cell 20 provided in some embodiments of this application after the first tab 242 and the tab connection portion 233 are welded and assembled in the thickness direction X of the wall portion. In the projection plane perpendicular to the thickness direction X of the wall portion, 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 first direction Y, or the angle between the length direction of the orthographic projection of the first solder mark 25 and the first 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 thickness direction X of the wall portion is a long strip structure extending along the first direction Y or in a direction approximately extending along the first direction Y, and the length direction of the orthographic projection of the first solder mark 25 in the projection plane perpendicular to the thickness direction X of the wall portion 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 portion 241.

[0227] For example, in a projection plane perpendicular to the thickness direction X of the wall portion, if the length direction of the orthographic projection of the first solder mark 25 is parallel to the first direction Y, then the angle between the length direction of the orthographic projection of the first solder mark 25 and the first direction Y is 0°. If the angle between the length direction of the orthographic projection of the first solder mark 25 and the first 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 first direction Y can be 0.1°, 0.2°, or 0.3°. The values ​​can be 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 any range between two of these values.

[0228] Optionally, the first solder mark 25 formed by welding each first tab 242 to the tab connection portion 233 can be one or more.

[0229] It should be noted that in other embodiments, the orthographic projection of the first solder mark 25 in the projection plane perpendicular to the thickness direction X of the wall portion can also be a rectangular, circular, elliptical or other structure.

[0230] In this embodiment, since the multiple first electrode segments 2411a are stacked along the first direction Y, and the sub-electrode tabs 2421 are bent towards the first 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 first direction Y. This ensures that the multiple sub-electrode tabs 2421 of the first electrode tab 242 are arranged along the first direction Y before being smoothed and bent. Therefore, after the multiple sub-electrode tabs 2421 are bent towards the first direction Y, the first solder mark 25 is applied perpendicular to the wall... The orthographic projection of the first solder mark 25 in the projection plane perpendicular to the thickness direction X of the wall is set as a strip structure extending along a straight trajectory. The length direction of the orthographic projection of the first solder mark 25 in the projection plane perpendicular to the thickness direction X of the wall is parallel to the first direction Y or the angle between the first solder mark 25 and the first direction Y is less than or equal to 30°. This enables the first solder mark 25 to be interconnected with more sub-tabs 2421, thereby improving the current flow effect between the first tab 242 and the tab connection 233, and improving the connection stability between the first tab 242 and the tab connection 233.

[0231] In some embodiments, see Figure 14 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 second direction Z, and the thickness direction X, the first direction Y, and the second direction Z of the wall are perpendicular to each other. That is, in the projection plane perpendicular to the thickness direction X of the wall, the orthographic projections of the multiple first solder marks 25 are arranged at intervals along its width direction.

[0232] 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 second direction Z, the orthographic projection of the plurality of first solder marks 25 in the projection plane perpendicular to the thickness direction X of the wall portion 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 tab connection portion 233, thereby further improving the current flow effect between the first tab 242 and the tab connection portion 233, and further improving the first tab... The connection stability between the sub-electrode 2421 and the electrode connection 233 is improved. On the other hand, even if there is a connection failure between the sub-electrode 2421 and part of the first solder mark 25, the provision of multiple first solder marks 25 enables the sub-electrode 2421 to maintain connection with the electrode connection 233 through the remaining first solder marks 25. This improves the fault tolerance rate of the welding assembly between the sub-electrode 2421 and the electrode connection 233, and improves the electrical connection stability between the sub-electrode 2421 and the electrode connection 233, thereby reducing the risk of connection failure between the sub-electrode 2421 and the electrode connection 233.

[0233] In some embodiments, combined with Figure 6 and Figure 14 As shown, the plurality of sub-tabs 2421 include a plurality of first sub-tabs 24211 fixedly connected to the first solder pads 25, and each first sub-tab 24211 is fixedly connected to at least two first solder pads 25.

[0234] Each first sub-taper 24211 is fixedly connected to at least two first solder marks 25, meaning that the sub-taper 2421 welded to the taper connection portion 233 is penetrated by at least two first solder marks 25, resulting in at least two solder marks 2421a formed on the sub-taper 2421 welded to the taper connection portion 233 (e.g., Figure 7 (As shown).

[0235] In this embodiment, by fixing each first sub-taper 24211 to at least two first solder marks 25, each sub-taper 2421 that is welded to the electrode connection portion 233 is passed through by at least two first solder marks 25. On the one hand, this can increase the flow area and flow path between the first sub-taper 24211 and the electrode connection portion 233. On the other hand, it can still electrically connect the first sub-taper 24211 to the electrode connection portion 233 through other first solder marks 25 even if the connection between the first sub-taper 24211 and one or more first solder marks 25 fails. This is beneficial to improving the electrical connection stability between the first sub-taper 24211 and the electrode connection portion 233.

[0236] In some embodiments, please continue to see Figure 14 As shown, in the projection plane perpendicular to the thickness direction X of the wall portion, the width of the orthographic projection of the first solder mark 25 in the second direction Z is 0.5mm-5mm, and the thickness direction X, the first direction Y, and the second direction Z of the wall portion are perpendicular to each other.

[0237] Among them, Figure 14 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 thickness direction X of the wall portion in the second direction Z is W, that is, 0.5mm≤W≤5mm, and in some embodiments, 1mm≤W≤2mm.

[0238] For example, the width W of the orthographic projection of the first solder mark 25 in the projection plane perpendicular to the thickness direction X of the wall portion in the second 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.

[0239] 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 thickness direction X of the wall portion in the second 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-electrode 2421, thereby improving the current flow effect between the first electrode 242 and the electrode connection portion 233, and also improving the connection stability between the first electrode 242 and the electrode connection portion 233. On the other hand, the width of the orthographic projection of the first solder mark 25 in the projection plane perpendicular to the thickness direction X of the wall portion in the second 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 welding the electrode connection portion 233 and the first electrode 242 is too large, which helps to reduce the power required for welding and assembling the electrode connection portion 233 and the first electrode 242, and can reduce the area of ​​the sub-electrode 2421 that is passed through by the first solder mark 25, thereby reducing the risk of damage to the sub-electrode 2421.

[0240] According to some embodiments of this application, see Figure 7 As shown, the area through which the sub-electrode 2421 is penetrated by the first solder mark 25 forms a solder mark area 2421a. 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 2421a on the same sub-electrode 2421 is S2, satisfying 0.0075≤S2 / S1≤0.1.

[0241] Wherein, S1 is the area of ​​one side of the surface of a single sub-taper 2421 in its thickness direction after it is unfolded. The solder area 2421a is the area through which the sub-taper 2421 is passed by the corresponding first solder part 25, and is also the area where the sub-taper 2421 is connected to the corresponding first solder part 25. It is also the area where the sub-taper 2421 and the electrode connecting part 233 are welded together to form the first solder part 25. Correspondingly, if only one solder area 2421a is formed on the sub-taper 2421, then S2 is the area of ​​the solder area 2421a. If multiple solder areas 2421a are formed on the sub-taper 2421, then S2 is the sum of the areas of the multiple solder areas 2421a.

[0242] If the sub-tab 2421 is unfolded and the thickness direction of the sub-tab 2421 is set to be parallel to the first direction Y (e.g.) Figure 7 As shown), S1 is the area of ​​the orthographic projection of the sub-tab 2421 in the projection plane perpendicular to the first 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-tab 2421 in the projection plane perpendicular to the first 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-tab 2421 to the area of ​​the orthographic projection of the corresponding sub-tab 2421 in the projection plane perpendicular to the first direction Y.

[0243] 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.

[0244] In this embodiment, on the one hand, the sum of the areas of all solder areas 2421a 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 tab connection 233, thereby improving the current flow effect between the individual sub-tab 2421 and the tab connection 233, and also improving the connection stability between the individual sub-tab 2421 and the tab connection 233. On the other hand, the sum of the areas of all solder areas 2421a 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 traversed by the first solder part 25 is too large, which helps to reduce the welding difficulty between the individual sub-tab 2421 and the tab connection 233, and also helps to reduce the power required for welding and assembling the tab connection 233 and the first tab 242.

[0245] According to some embodiments of this application, refer to Figure 6 Please refer to further details. Figure 15 As shown, Figure 15This is a partial cross-sectional view of the electrode assembly 24 and the tab connection portion 233 of the first current collector 23 of the battery cell 20 provided in some embodiments of this application after being assembled together. A plurality of sub-tabs 2421 include a plurality of first sub-tabs 24211 fixedly connected to a first solder mark 25. Along the thickness direction X of the wall portion, portions of the plurality of first sub-tabs 24211 connected to the first solder mark 25 are stacked on the side of the tab connection portion 233 facing away from the main body 241. A first tab 242 has a second surface 2422 facing away from the tab connection portion 233, and at least a portion of the first solder mark 25 extends from the second surface 2422 into the tab connection portion 233.

[0246] Among them, the first sub-electrode 24211 is the sub-electrode 2421 among the multiple sub-electrode 2421 of the first electrode 242 that is welded to the electrode connection portion 233. That is, the first sub-electrode 24211 is the sub-electrode 2421 among the multiple sub-electrode 2421 of the first electrode 242 that is penetrated by the first solder mark portion 25. In other words, the sub-electrode 2421 among the multiple sub-electrode 2421 that has the solder mark area 2421a is the first sub-electrode 24211 (e.g., Figure 7 (As shown).

[0247] Optionally, among the plurality of sub-taps 2421 of the first electrode tab 242, all sub-taps 2421 may be the first sub-taps 24211, or only a portion of the sub-taps 2421 may be the first sub-taps 24211. That is, only a portion of the plurality of sub-taps 2421 of the first electrode tab 242 are welded to the electrode tab connection portion 233, so that only a portion of the plurality of sub-taps 2421 of the first electrode tab 242 are passed through by the first solder mark portion 25.

[0248] Along the thickness direction X of the wall portion, a plurality of first sub-taps 24211 are stacked on the side of the tab connection portion 233 away from the main body portion 241, where the portions of the plurality of first sub-taps 24211 are stacked and located between the tab connection portion 233 and the terminal connection portion 231. The portions of the plurality of first sub-taps 24211 located between the tab connection portion 233 and the terminal connection portion 231 are welded to the tab connection portion 233 to form the first solder mark portion 25, such that the portion of the first solder mark portion 25 connected to the first tab 242 is located on the side of the tab connection portion 233 away from the main body portion 241.

[0249] The first tab 242 has a second surface 2422 facing away from the main body 241, and at least a portion of the first solder mark 25 extends from the second surface 2422 into the tab connection portion 233. That is, in the thickness direction X of the wall portion, the first solder mark 25 is a structure in which at least a portion extends from the second surface 2422 on the side of the first tab 242 facing away from the main body 241 toward the main body 241 and into the tab connection portion 233, such that the outer surface of the first solder mark 25 facing away from the main body 241 in the thickness direction X of the wall portion is connected to the second surface 2422, and the projection of the first solder mark 25 in the thickness direction X perpendicular to the wall portion is flat. In the plane, the orthographic projection of the portion where the first solder mark 25 is connected to the tab connection portion 233 can be a structure located within the orthographic projection of the portion where the first solder mark 25 is connected to the first tab 242. That is, when welding and assembling the first tab 242 and the tab connection portion 233, the welding equipment is a structure that welds and assembles the first tab 242 and the tab connection portion 233 from the side of the first tab 242 away from the main body portion 241 in the thickness direction X of the wall portion, so that the first solder mark 25 is a structure that first passes through a plurality of first sub-tabs 24211 stacked on the side of the tab connection portion 233 away from the main body portion 241 and then extends into the tab connection portion 233.

[0250] Optionally, the outer surface of the first solder mark 25 facing away from the main body 241 in the thickness direction X of the wall portion can be a structure that is flush with the second surface 2422, or a structure in which part of the first solder mark 25 protrudes from the second surface 2422.

[0251] In this embodiment, by stacking multiple first sub-tabs 24211 connected to the first solder mark 25 on the side of the tab connection portion 233 away from the main body portion 241, and at least a portion of the first solder mark 25 extending from the second surface 2422 of the first tab 242 into the tab connection portion 233, the first tab 242 is partially located on the side of the tab connection portion 233 away from the main body portion 241, and the first tab 242 and the tab connection portion 233 are welded together in the thickness direction X of the wall from the side of the first tab 242 away from the tab connection portion 233. The battery cell 20 with this structure can achieve the following: firstly, the multiple sub-tabs 242 of the first tab 242 are first assembled together. The structure of smoothing and bending the first tab 242 and the tab connection 233 and then welding them together allows each sub-tab 2421 to adapt to the length change caused by bending during the smoothing and bending process, thereby reducing the phenomenon of local stress concentration or local bulging of the sub-tab 2421 during the smoothing and bending process. It can also reduce the risk of short circuit inside the battery cell 20 caused by the first sub-tab 2421 being inserted into the main body 241. On the other hand, it can reduce the welding difficulty between the first tab 242 and the tab connection 233 after smoothing and bending, and facilitate the smoothing and bending of multiple sub-tabs 2421 of the first tab 242 based on the tab connection 233, thereby reducing the bending difficulty of the sub-tabs 2421.

[0252] In some embodiments, see Figure 6 As shown, all the sub-tabs 2421 in the first electrode tab 242 are fixedly connected to the first solder mark portion 25. That is, all the sub-tabs 2421 in the first electrode tab 242 are first sub-tabs 24211. Correspondingly, all the sub-tabs 2421 in the first electrode tab 242 are passed through by at least one first solder mark portion 25. At least one solder mark area 2421a is formed on each sub-tab 2421 in the first electrode tab 242.

[0253] In this embodiment, by fixing all the sub-tabs 2421 in the first tab 242 to the first solder part 25, each sub-tab 2421 in the first tab 242 is welded to the tab connection part 233, thereby further improving the current flow effect and connection stability between the first tab 242 and the tab connection part 233, and reducing the risk of excessively long current path or connection failure of the first pole segment 2411a due to the sub-tabs 2421 on some pole segments 2411a not being welded to the tab connection part 233.

[0254] In some embodiments, see Figure 6As shown, along the thickness direction X of the wall portion, the thickness of the portion of the first solder mark 25 extending into the tab connection portion 233 is T1, and the thickness of the tab connection portion 233 is T2, satisfying 0.25≤T1 / T2≤0.75.

[0255] Wherein, T1 is the maximum dimension of the portion of the first solder mark 25 located within the tab connection portion 233 in the thickness direction X of the wall portion, and is also the maximum dimension of the portion of the first solder mark 25 connected to the tab connection portion 233 in the thickness direction X of the wall portion. Correspondingly, T2 is the thickness of the tab connection portion 233, and is also the sum of the minimum distance between the area of ​​the tab connection portion 233 facing the main body portion 241 in the thickness direction X of the wall portion 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 molten pool depth of the first solder mark 25 within the tab connection portion 233 to the thickness of the tab connection portion 233.

[0256] 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.

[0257] In this embodiment, on the one hand, the thickness of the portion of the first solder mark 25 extending into the tab connection portion 233 is set to be greater than or equal to 0.25 times the thickness of the tab connection portion 233, so as to increase the welding penetration of the first solder mark 25 in the tab connection portion 233, thereby improving the current flow effect between the first tab 242 and the tab connection portion 233, and also improving the connection stability between the first tab 242 and the tab connection portion 233. On the other hand, the thickness of the portion of the first solder mark 25 extending into the tab connection portion 233 is set to be less than or equal to 0.75 times the thickness of the tab connection portion 233, so as to reduce the risk of the tab connection portion 233 being burned through and damaging other components.

[0258] According to some embodiments of this application, in embodiments where multiple first sub-tabs 24211 connected to the first solder mark 25 are stacked on the side of the tab connection portion 233 facing away from the main body portion 241, combined with Figure 6 and Figure 7 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.

[0259] 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.

[0260] 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 first direction Y (e.g.) Figure 7 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 thickness direction X of the wall portion, 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.

[0261] 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.

[0262] In this embodiment, when multiple first sub-taps 24211 connected to the first solder mark 25 are stacked on the side of the tab connecting portion 233 away from the main body 241, the extension dimension of the sub-taps 2421 from one end connected to the first pole segment 2411a to the end away from the first pole segment 2411a is set to be greater than or equal to 5mm. This reduces the difficulty of bending the multiple sub-taps 2421 toward the first direction Y and extending them to the side of the tab connecting portion 233 away from the main body 241. It also reduces the difficulty of stacking and welding the multiple sub-taps 2421 with the tab connecting portion 233 after bending. Furthermore, it helps to increase the area where the sub-taps 2421 can be stacked and welded with the tab connecting portion 233 after bending. On the other hand, since the multiple sub-tabs 2421 of the first tab 242 are not fixed to each other before being welded and assembled with the tab connection part 233, the multiple sub-tabs 2421 can move and shift relative to each other during the process of smoothing and bending the first tab 242. Thus, by setting the extension dimension of the sub-tab 2421 from one end connected to the first electrode segment 2411a to the end away from the first electrode segment 2411a to less than or equal to 40mm, the phenomenon of redundancy or local bulging of the sub-tab 2421 after bending can be effectively alleviated. This is to optimize the space occupied by the first tab 242 as a whole in the thickness direction X of the wall, 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.

[0263] According to some embodiments of this application, in embodiments where multiple first sub-tabs 24211 connected to the first solder mark 25 are stacked on the side of the tab connection portion 233 facing away from the main body portion 241, combined with Figure 5 and Figure 6 As shown, the thickness of the tab connection portion 233 along the thickness direction X of the wall portion is 0.3mm-4mm. In some embodiments, the thickness of the tab connection portion 233 along the thickness direction X of the wall portion can be 1mm-3mm.

[0264] Among them, Figure 6 In the middle, the thickness of the tab connection portion 233 in the thickness direction X of the wall portion is T2. Correspondingly, the thickness of the area where the tab connection portion 233 is connected to the first solder mark portion 25 in the thickness direction X of the wall portion is the sum of the minimum distance between the area of ​​the tab connection portion 233 facing the main body portion 241 and corresponding to the first solder mark portion 25 in the thickness direction X of the wall portion and the portion of the first solder mark portion 25 extending into the tab connection portion 233 in the thickness direction X of the wall portion.

[0265] For example, the thickness T2 of the tab connection portion 233 in the thickness direction X of the wall portion 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.

[0266] In this embodiment, when multiple first sub-tabs 24211 connected to the first solder mark 25 are stacked on the side of the tab connection portion 233 away from the main body portion 241, the thickness of the tab connection portion 233 in the wall thickness direction X is set to be greater than or equal to 0.3 mm. This reduces the risk of the tab connection portion 233 being burned or damaged after being soldered through, and also increases the depth of the molten pool of the first solder mark 25 in the tab connection portion 233, thereby improving the welding reliability between the first tab 242 and the tab connection portion 233. This also improves the structural strength of the tab connection 233. On the other hand, setting the thickness of the tab connection 233 in the thickness direction X of the wall to be less than or equal to 4mm alleviates the problem of the tab connection 233 occupying too much space between the first tab 242 and the main body 241. This helps to optimize the space occupied by the first tab 242 and the tab connection 233 as a whole in the thickness direction X of the wall, and also helps to reduce the difficulty of bending multiple sub-tabs 2421 toward the first direction Y and extending them to the side of the tab connection 233 away from the main body 241.

[0267] According to some embodiments of this application, see Figure 6 As shown, the first sub-taper 24211 has a connecting end 24211a connected to the first pole segment 2411a. In the projection plane perpendicular to the thickness direction X of the wall, at least a portion of the orthographic projection of the connecting end 24211a of the first sub-taper 24211 is located within the orthographic projection of the pole connecting portion 233, and the first sub-taper 24211, whose orthographic projection of the connecting end 24211a is located within the orthographic projection of the pole connecting portion 233, is bent around the pole connecting portion 233.

[0268] Among them, the connection end 24211a of the first sub-pole ear 24211 is the end where the first sub-pole ear 24211 is connected to the corresponding first pole segment 2411a.

[0269] In the projection plane perpendicular to the thickness direction X of the wall portion, the orthographic projection of the connecting end 24211a of at least a portion of the first sub-taper 24211 is located within the orthographic projection of the tab connecting portion 233, and the first sub-taper 24211 whose orthographic projection of the connecting end 24211a is located within the orthographic projection of the tab connecting portion 233 is bent around the tab connecting portion 233. That is, at least a portion of the multiple first sub-taper 24211 is a structure that extends from between the tab connecting portion 233 and the main body portion 241 and bends around the tab connecting portion 233 on one side in the first direction Y before extending to the side of the tab connecting portion 233 away from the main body portion 241, such that a portion of at least a portion of the multiple first sub-taper 24211 is a structure located between the tab connecting portion 233 and the main body portion 241 in the thickness direction X of the wall portion.

[0270] Optionally, only some of the first sub-taps 24211 may have their connecting ends 24211a located between the tab connecting portion 233 and the main body portion 241; alternatively, all the connecting ends 24211a of the first sub-taps 24211 may be located between the tab connecting portion 233 and the main body portion 241. For example, in... Figure 6 In the middle, the connecting end 24211a of a portion of the first sub-taper 24211 is located between the tab connecting portion 233 and the main body portion 241, and the orthographic projection of the connecting end 24211a of another portion of the first sub-taper 24211 in the projection plane perpendicular to the thickness direction X of the wall portion does not overlap with the orthographic projection of the tab connecting portion 233 in the projection plane perpendicular to the thickness direction X of the wall portion.

[0271] In this embodiment, by setting the orthographic projection of at least a portion of the connecting end 24211a of the first sub-taper 24211 in a projection plane perpendicular to the thickness direction X of the wall portion to a structure located within the orthographic projection of the tab connecting portion 233 in a projection plane perpendicular to the thickness direction X of the wall portion, the portion of the at least a portion of the first sub-taper 24211 welded to the tab connecting portion 233 is a structure located between the tab connecting portion 233 and the main body portion 241, such that this portion of the first sub-taper 24211 is a structure that starts from the side of the tab connecting portion 233 facing the main body portion 241, bends around the tab connecting portion 233, and extends to the side of the tab connecting portion 233 away from the main body portion 241. With this structure, the battery cell 20 can, on the one hand, ensure that at least part of the first tab 24211 acts as a separator between the tab connection portion 233 and the main body portion 241, thereby reducing the risk of the tab connection portion 233 being burned or damaged by welding through to the main body portion 241. On the other hand, it can enable the tab connection portion 233 and the first tab 242 to share a portion of space in the thickness direction X of the wall portion, and also enable the tab connection portion 233 and the first tab 242 to share a portion of space in the first direction Y. This is beneficial to optimize the overall space occupied by the tab connection portion 233 and the first tab 242, thereby improving the internal space utilization rate of the battery cell 20 and thus improving the energy density of the battery cell 20.

[0272] In an embodiment where the orthographic projection of at least a portion of the connecting end 24211a of the first sub-taper 24211 in the projection plane perpendicular to the thickness direction X of the wall portion lies within the orthographic projection of the taper connecting portion 233, see [reference needed]. Figure 6 As shown, along the thickness direction X of the wall portion, the portion of the first sub-taper 24211 located between the taper connection portion 233 and the main body portion 241 gradually moves away from the main body portion 241 from the end connected to the first pole segment 2411a to the end away from the first pole segment 2411a. In other words, along the thickness direction X of the wall portion, the distance between the portion of the first sub-taper 24211 located between the taper connection portion 233 and the main body portion 241 and the main body portion 241 gradually increases from the end connected to the first pole segment 2411a to the end away from the first pole segment 2411a.

[0273] It should be noted that, along the thickness direction X of the wall portion, the portion of the first sub-electrode 24211 located between the electrode connecting portion 233 and the main body portion 241 gradually moves away from the main body portion 241 from the end connected to the first electrode segment 2411a to the end away from the first electrode segment 2411a. Correspondingly, the portion of the first sub-electrode 24211 located between the electrode connecting portion 233 and the main body portion 241 from the end connected to the first electrode segment 2411a to the end away from the first electrode segment 2411a can be a structure that is inclined and gradually moves away from the main body portion 241 as a whole (the extension direction is set at an acute angle to the thickness direction X of the wall portion), or it can be a structure that is partially inclined and gradually moves away from the main body portion 241 and partially extends along the thickness direction X of the wall portion, or it can be a structure that is partially inclined and gradually moves away from the main body portion 241 and partially extends along the first direction Y, or it can be a structure that is partially inclined and gradually moves away from the main body portion 241, partially extends along the first direction Y and partially extends along the thickness direction X of the wall portion.

[0274] In this embodiment, since the first electrode tab 242 is bent toward the first direction Y and the multiple sub-electrode 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 electrode tab connection portion 233, the multiple sub-electrode tabs 2421 of the first electrode tab 242 are structures that can be smoothed and bent before being welded and assembled with the electrode tab connection portion 233. Thus, the portion of the first sub-electrode tab 24211 located between the electrode tab connection portion 233 and the main body portion 241 is configured to extend from one end connected to the first electrode segment 2411a to the end away from the first electrode segment 2411a. The structure gradually moves away from the main body 241 to reduce the occurrence of local bulging or swelling of the first sub-tab 24211 located between the tab connection 233 and the main body 241 due to stress. This reduces the risk of cracking or breakage of the first sub-tab 24211 located between the tab connection 233 and the main body 241 during assembly or use. It also saves the space occupied by the portions of the first sub-tab 24211 located between the tab connection 233 and the main body 241 in the thickness direction X of the wall, thereby increasing the energy density of the battery cell 20.

[0275] Of course, the structure of the battery cell 20 is not limited to this; the battery cell 20 can also have other structures. See some embodiments of this application for details. Figure 15 As shown, the first sub-taper 24211 has a connecting end 24211a connected to the first pole segment 2411a. In the projection plane perpendicular to the thickness direction X of the wall, the orthographic projection of the pole connecting portion 233 does not overlap with the orthographic projection of the connecting ends 24211a of all the first sub-taper 24211.

[0276] In this case, all the first sub-taps 24211 in the first electrode tab 242 are not located between the electrode tab connecting portion 233 and the main body portion 241, so that the first sub-taps 24211 do not extend to the portion between the electrode tab connecting portion 233 and the main body portion 241, so that all the first sub-taps 24211 are structures that extend from one side of the electrode tab connecting portion 233 in the first direction Y and bend to the side of the electrode tab connecting portion 233 away from the main body portion 241.

[0277] It should be noted that in this embodiment, the tab connection 233 can be a structure that directly abuts against the main body 241, or it can be a structure that indirectly abuts against the main body 241 through other components, such as the heat insulation member 30 and / or the support member 31.

[0278] In this embodiment, by setting the orthographic projection of the connection ends 24211a of all the first sub-tabs 24211 in the projection plane perpendicular to the thickness direction X of the wall portion to a structure that does not overlap with the orthographic projection of the tab connection portion 233 in the projection plane perpendicular to the thickness direction X of the wall portion, the tab connection portion 233 is located between the first sub-tabs 24211 and the main body portion 241, and the first sub-tabs 24211 are arranged such that they start from one side of the tab connection portion 233 in the first direction Y, bend around the tab connection portion 233, and extend to the side of the tab connection portion 233 away from the main body portion 241. A battery cell 20 with this structure is described. On the one hand, it can reduce the difficulty of smoothing and bending the first sub-tab 24211, and reduce the difficulty of stacking and welding the multiple sub-tabs 2421 of the first tab 242 with the tab connection part 233. On the other hand, it can realize that the tab connection part 233 and the first tab 242 share part of the space in the thickness direction X of the wall, and can further optimize the size of the tab connection part 233 and the main body part 241 in the thickness direction X of the wall, thereby saving the space occupied by the first tab 242 and the tab connection part 233 in the thickness direction X of the wall, so as to improve the internal space utilization of the battery cell 20, and thus improve the energy density of the battery cell 20.

[0279] According to some embodiments of this application, see Figure 4 , Figure 5 , Figure 6 as well as Figure 15 As shown, the battery cell 20 may also include a heat insulation member 30. At least a portion of the heat insulation member 30 is disposed between the tab connection portion 233 and the main body portion 241 in the thickness direction X of the wall portion, and at least a portion of the orthographic projection of the first solder mark portion 25 is located within the orthographic projection of the heat insulation member 30 in the projection plane perpendicular to the thickness direction X of the wall portion.

[0280] The heat insulation component 30 is at least partially located between the tab connection portion 233 and the main body portion 241, such that the first weld mark portion 25 formed by welding the first tab 242 and the tab connection portion 233 is located on the side of the heat insulation component 30 away from the main body portion 241, so as to play a heat insulation role between the tab connection portion 233 and the main body portion 241, thereby reducing the risk of the first tab 242 and the first current collector 23 burning or damaging the main body portion 241 during welding assembly. The connection structure of the heat insulation component 30 between the tab connection portion 233 and the main body portion 241 can be various. The heat insulation component 30 can be a structure connected to the surface of the tab connection portion 233 facing the main body portion 241, or it can be a structure connected to the end face of the main body portion 241 facing the tab connection portion 233.

[0281] In the projection plane perpendicular to the thickness direction X of the wall portion, at least a portion of the orthographic projection of the first solder mark 25 is located within the orthographic projection of the heat insulation member 30. That is, the heat insulation member 30 is a structure that covers at least a portion of the first solder mark 25 in the thickness direction X of the wall portion. It can be that the heat insulation member 30 only covers a portion of the first solder mark 25, or it can be that the heat insulation member 30 covers the entire first solder mark 25.

[0282] 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.

[0283] As an example, the material of the insulation element 30 may include polyimide or polytetrafluoroethylene, etc.

[0284] In this embodiment, by setting at least a portion of the heat insulation member 30 in the thickness direction X of the wall portion to a structure located between the tab connection portion 233 and the main body portion 241, and setting at least a portion of the orthographic projection of the first solder mark portion 25 in a projection plane perpendicular to the thickness direction X of the wall portion to a structure located within the orthographic projection of the heat insulation member 30 in a projection plane perpendicular to the thickness direction X of the wall portion, the first solder mark portion 25 is located on the side of the heat insulation member 30 away from the main body portion 241 in the thickness direction X of the wall portion. This allows the heat insulation member 30 to play a heat insulation role between the first solder mark portion 25 and the main body portion 241, thereby reducing the phenomenon of the tab connection portion 233 and the first tab 242 burning the main body portion 241 and other components during the welding connection and formation of the first solder mark portion 25, thus improving the assembly quality of the battery cell 20.

[0285] In some embodiments, see Figure 6 as well as Figure 15As shown, in the projection plane perpendicular to the thickness direction X of the wall portion, 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 thickness direction X of the wall portion.

[0286] In this embodiment, by setting the entire orthographic projection of the first solder mark 25 in the projection plane perpendicular to the thickness direction X of the wall portion to be located within the orthographic projection of the heat insulation member 30 in the projection plane perpendicular to the thickness direction X of the wall portion, the heat insulation effect of the heat insulation member 30 between the first solder mark 25 and the main body portion 241 can be further improved. This can further reduce the phenomenon of the tab connection portion 233 and the first tab 242 burning the main body portion 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.

[0287] 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 tab connection portion 233 and the main body portion 241, but also provide insulation between the tab connection portion 233 and the main body portion 241.

[0288] In this embodiment, the orthographic projection of the tab connection 233 is located within the orthographic projection of the heat insulation member 30 in the projection plane perpendicular to the thickness direction X of the wall portion, so as to improve the insulation effect of the heat insulation member 30 in isolating the tab connection 233 and the main body portion 241. Of course, in other embodiments, the orthographic projection of the tab connection 233 may also be only partially located within the orthographic projection of the heat insulation member 30 in the projection plane perpendicular to the thickness direction X of the wall portion.

[0289] 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 tab connection portion 233 and the main body portion 241, thereby reducing the risk of short circuit between the tab connection portion 233 and the main body portion 241 during use and improving the reliability of the battery cell 20.

[0290] In some embodiments, see Figure 6 as well as Figure 15 As shown, the heat insulation member 30 is connected to the surface of the tab connection portion 233 facing the main body portion 241.

[0291] For example, the heat insulation member 30 is bonded to the surface of the tab connection portion 233 facing the main body portion 241. For instance, the heat insulation member 30 can be bonded to the surface of the tab connection portion 233 facing the main body portion 241 by adhesive or double-sided adhesive. Of course, in other embodiments, the heat insulation member 30 can also be a structure that is snapped onto the tab connection portion 233.

[0292] In this embodiment, by setting the heat insulation component 30 to be connected to the surface of the tab connection portion 233 facing the main body portion 241, on the one hand, the heat insulation component 30 can be assembled together with the tab connection portion 233 between the first tab 242 and the main body portion 241, which helps to reduce the difficulty of setting the heat insulation component 30 between the tab connection portion 233 and the main body portion 241 and optimizes the production cycle. On the other hand, it can improve the stability and reliability of the heat insulation component 30 between the tab connection portion 233 and the main body portion 241, which helps to reduce the risk of the heat insulation component 30 falling off between the tab connection portion 233 and the main body portion 241 during the welding process between the tab connection portion 233 and the first tab 242.

[0293] According to some embodiments of this application, please continue to refer to Figure 6 as well as Figure 15 As shown, the battery cell 20 may also include a support member 31, which is supported between the tab connection portion 233 and the main body portion 241 along the thickness direction X of the wall portion, and at least a portion of the orthographic projection of the first solder mark portion 25 is located within the orthographic projection of the support member 31 in the projection plane perpendicular to the thickness direction X of the wall portion.

[0294] The support member 31 serves to support the electrode connecting part 233 and the main body part 241, so that during the welding and assembly of the first electrode 242 and the electrode connecting part 233, the electrode connecting part 233 can act on the main body part 241 through the support member 31 to stabilize the electrode connecting part 233. Optionally, the support member 31 can be made of various materials, such as rubber, plastic or ceramic.

[0295] It should be noted that the support member 31 and the electrode tab connection portion 233 can be in direct contact or indirect contact through other components. In other words, the support member 31 can directly support the electrode tab connection portion 233 or indirectly support it through other components. Similarly, the support member 31 and the main body portion 241 can be in direct contact or indirect contact through other components.

[0296] For example, in Figure 6 In the illustrated embodiment, at least a portion of the connecting end 24211a of the first sub-taper 24211 is a structure located between the tab connecting portion 233 and the main body portion 241, such that at least a portion of the first sub-taper 24211 is located between the tab connecting portion 233 and the main body portion 241. Correspondingly, the support member 31 is a structure that abuts against the portion of the first sub-taper 24211 located between the tab connecting portion 233 and the main body portion 241. Figure 15In the illustrated embodiment, the connection ends 24211a of all the first sub-tabs 24211 are not located between the tab connection portion 233 and the main body portion 241. Correspondingly, the support member 31 is a structure that directly abuts against the main body portion 241.

[0297] 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 tab connection portion 233, such that the support member 31 is a structure that indirectly abuts against the tab connection portion 233 through the heat insulation element 30. It should be noted that in this embodiment, the heat insulation element 30 can be a structure connected to the tab connection portion 233 or a structure connected to the support member 31.

[0298] In this embodiment, by providing a support member 31 between the tab connection portion 233 and the main body portion 241, and at least a portion of the orthographic projection of the first solder mark portion 25 in the projection plane perpendicular to the thickness direction X of the wall portion is located within the orthographic projection of the support member 31 in the projection plane perpendicular to the thickness direction X of the wall portion, the support member 31 can provide support and stability for the tab connection portion 233, thereby reducing the welding gap between the first tab 242 and the tab connection portion 233, and reducing the shaking phenomenon of the tab connection portion 233 during the welding assembly process, thereby reducing the risk of incomplete welding between the first tab 242 and the tab connection portion 233, and improving the welding quality of the first tab 242 and the tab connection portion 233.

[0299] According to some embodiments of this application, please refer to Figure 16 As shown, Figure 16 This is a partial cross-sectional view of the electrode assembly 24 and the tab connection portion 233 of the first current collector 23 of the battery cell 20 provided in other embodiments of this application after being assembled together. A plurality of sub-tabs 2421 include a plurality of first sub-tabs 24211 fixedly connected to a first solder mark 25. Along the thickness direction X of the wall portion, portions of the plurality of first sub-tabs 24211 connected to the first solder mark 25 are stacked on the side of the tab connection portion 233 facing the main body portion 241. The tab connection portion 233 has a third surface 233a facing away from the main body portion 241, and at least a portion of the first solder mark 25 extends from the third surface 233a into the first tab 242.

[0300] Along the thickness direction X of the wall portion, a plurality of first sub-taps 24211 are stacked on the side of the tab connection portion 233 facing the main body portion 241, where the portions of the plurality of first sub-taps 24211 are stacked and located between the tab connection portion 233 and the main body portion 241. The portions of the plurality of first sub-taps 24211 located between the tab connection portion 233 and the main body portion 241 are welded to the tab connection portion 233 to form the first solder mark portion 25, such that the portion of the first solder mark portion 25 connected to the first tab 242 is located on the side of the tab connection portion 233 facing the main body portion 241.

[0301] The tab connection portion 233 has a third surface 233a facing away from the main body portion 241, and at least a portion of the first solder mark portion 25 extends from the third surface 233a into the first tab 242. That is, in the thickness direction X of the wall portion, the first solder mark portion 25 has a structure in which at least a portion extends from the third surface 233a of the tab connection portion 233 facing away from the main body portion 241 toward the main body portion 241 and into the first tab 242, such that the outer surface of the first solder mark portion 25 facing away from the main body portion 241 in the thickness direction X of the wall portion is connected to the third surface 233a, and such that in the vertical direction... In the projection plane of the wall thickness 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 tab connection portion 233. That is, when welding and assembling the tab connection portion 233 and the first tab 242, the welding equipment is a structure that welds and assembles the tab connection portion 233 and the first tab 242 from the side of the tab connection portion 233 away from the main body portion 241 in the wall thickness direction X, so that the first solder mark 25 is a structure that first passes through the entire tab connection portion 233 and then extends into the first tab 242.

[0302] Optionally, the outer surface of the first solder mark 25 facing away from the main body 241 in the thickness direction X of the wall portion can be a structure that is flush with the third surface 233a, or a structure in which part of the first solder mark 25 protrudes from the third surface 233a.

[0303] In this embodiment, by stacking multiple first sub-tabs 24211 connected to the first solder mark 25 on the side of the tab connection portion 233 facing the main body portion 241, and at least a portion of the first solder mark 25 extending from the third surface 233a of the tab connection portion 233 into the first tab 242, the tab connection portion 233 is at least partially located on the side of the first tab 242 away from the main body portion 241, and the tab connection portion 233 and the first tab 242 are welded together in the thickness direction X of the wall portion. The battery cell 20 with this structure can weld and assemble the tab connection portion 233 and the first tab 242 together. When the first electrode tab 242 is connected to the first electrode tab 242, the tooling fixture can be configured to press down on multiple first sub-electrodes 24211 and weld them together through the electrode tab connecting part 233. This ensures that the first sub-electrodes 24211 are always pressed down by the electrode tab connecting part 233 during the welding and assembly process. This reduces the risk of local warping or cracking of the first sub-electrodes 24211 during the welding and assembly process, and also reduces the welding gap between multiple first sub-electrodes 24211, thereby reducing the risk of incomplete welding. This is beneficial to improving the welding quality between the electrode tab connecting part 233 and the first electrode tab 242. On the other hand, it can reduce the welding difficulty between the first electrode tab 242 and the electrode tab connecting part 233 after the bend is smoothed.

[0304] In some embodiments, please continue to see Figure 16 As shown, in the bending direction of the first sub-taper 24211, at least one sub-taper 2421 located on one side of the plurality of first sub-taper 24211 bends around the tab connection portion 233 and extends to the side of the tab connection portion 233 away from the main body portion 241.

[0305] Wherein, the bending direction of the first sub-electrode 24211 is the extension direction of the part of the first sub-electrode 24211 that is fixedly connected to the first solder part 25 on the extension trajectory from the end of the first sub-electrode 24211 connected to the first pole segment 2411a to the extension trajectory away from the first pole segment 2411a, and the bending direction of the first sub-electrode 24211 is unidirectional in the first direction Y.

[0306] At least one of the multiple sub-taps 2421 located on one side of the multiple first sub-taps 24211 is bent around the tab connection portion 233 and extends to the side of the tab connection portion 233 away from the main body portion 241. That is, the sub-taps 2421 that are not fixedly connected to the first solder mark portion 25 are arranged in the first direction Y with the multiple first sub-taps 24211, and the sub-taps 2421 that are not fixedly connected to the first solder mark portion 25 are located on one side of the multiple first sub-taps 24211 in the bending direction of the first sub-taps 24211. In the description, the sub-taper 2421 that is not fixedly connected to the first solder mark portion 25 is the second sub-taper 24212. Correspondingly, all the second sub-taper 24212 are located on one side of the multiple first sub-taper 24211 in the bending direction of the first sub-taper 24211, and at least one second sub-taper 24212 is bent around the electrode connecting portion 233 on one side in the first direction Y and extends to the side of the electrode connecting portion 233 away from the main body portion 241, such that a portion of at least one second sub-taper 24212 is located on the side of the electrode connecting portion 233 away from the main body portion 241.

[0307] For example, in Figure 16 In the projection plane perpendicular to the thickness direction X of the wall portion, the orthographic projections of all the second sub-taperes 24212 are located within the orthographic projection of the main body portion 241, so as to reduce the phenomenon of interference between the second sub-taperes 24212 and other components after they protrude from the surface of the main body portion 241 on the side in the first direction Y.

[0308] In this embodiment, by setting at least one of the multiple sub-taps 2421 that is not connected to the first solder mark portion 25 and is located on one side of the multiple first sub-taps 24211 in the bending direction of the first sub-taps 24211 to a structure that bends around the tab connection portion 233 and extends to the side of the tab connection portion 233 away from the main body portion 241, the overall regularity of the first tab 242 is improved, which helps to alleviate the phenomenon that some sub-taps 2421 located in the edge area of ​​the multiple sub-taps 2421 are redundantly occupying space or are inserted upside down into the main body portion 241.

[0309] Of course, the structure of the battery cell 20 is not limited to this. In some embodiments, the battery cell 20 can also have other structures. For example, in an embodiment where multiple first sub-tabs 24211 connected to the first soldering portion 25 are stacked on the side of the tab connection portion 233 facing the main body portion 241, all the sub-tabs 2421 of the first tab 242 can be fixedly connected to the first soldering portion 25, and all the sub-tabs 2421 of the first tab 242 are located on the side of the tab connection portion 233 facing the main body portion 241 in the thickness direction X of the wall portion. In other words, among the multiple sub-tabs 2421, there is no second sub-tab 24212 that is not fixedly connected to the first solder mark 25. Correspondingly, in the same first tab 242, in the bending direction of the first sub-tab 24211, a portion of the first pole segments 2411a located on one side of the multiple first pole segments 2411a connected to the first sub-tab 24211 is a structure that is not connected to the sub-tab 2421.

[0310] In this embodiment, by providing all the sub-taps 2421 in the first electrode tab 242 on the side of the electrode tab connection portion 233 facing the main body portion 241 and welding them to the electrode tab connection portion 233, the waste of sub-taps 2421 in the first electrode tab 242 can be reduced, thereby reducing manufacturing costs. On the other hand, the redundant space occupied by the sub-taps 2421 due to not being welded to the electrode tab connection portion 233 can be alleviated.

[0311] In some embodiments, see Figure 16 As shown, within the same first electrode tab 242, multiple sub-electrodes 2421 arranged sequentially from the first to the nth along the bending direction of the first sub-electrode tab 24211 are all first sub-electrodes 24211, where n is greater than or equal to 2. That is, the first to the nth sub-electrodes 2421 arranged sequentially along the bending direction of the first sub-electrode tab 24211 within the same first electrode tab 242 are all welded to the electrode tab connecting part 233.

[0312] In this embodiment, by designating multiple sub-electrodes 2421 arranged sequentially from the first to the nth along the bending direction of the first sub-electrodes 24211 in the same first electrode tab 242 as first sub-electrodes 24211, and by welding multiple sub-electrodes 2421 arranged sequentially from the first in the bending direction of the first sub-electrodes 24211 to the electrode tab connection portion 233, the welding range between the electrode tab connection portion 233 and the first electrode tab 242 can be increased, and the first solder mark portion 25 can be fixedly connected to more sub-electrodes 2421, thereby improving the connection stability and overcurrent effect between the electrode tab connection portion 233 and the first electrode tab 242.

[0313] In some embodiments, please continue to see Figure 16 As shown, the first sub-taper 24211 has a connecting end 24211a connected to the first pole segment 2411a. In the projection plane perpendicular to the thickness direction X of the wall, at least a portion of the orthographic projection of the connecting end 24211a of the first sub-taper 24211 is located within the orthographic projection of the pole connecting portion 233.

[0314] In the projection plane perpendicular to the thickness direction X of the wall portion, the orthographic projection of at least a portion of the connecting end 24211a of the first sub-taper 24211 lies within the orthographic projection of the tab connecting portion 233. That is, at least a portion of the multiple first sub-tapers 24211 are structures that extend from between the tab connecting portion 233 and the main body 241, bend towards the first direction Y, and are at least partially located between the tab connecting portion 233 and the main body 241. It should be noted that after bending, the first sub-taper 24211 can be a structure extending beyond one side of the tab connecting portion 233 in the first direction Y, or it can be a structure that does not extend beyond both sides of the tab connecting portion 233 in the first direction Y.

[0315] Optionally, only some of the first sub-taps 24211 may have their connecting ends 24211a located between the tab connecting portion 233 and the main body portion 241; alternatively, all the connecting ends 24211a of the first sub-taps 24211 may be located between the tab connecting portion 233 and the main body portion 241. For example, in... Figure 16 In the middle, the connecting end 24211a of a portion of the first sub-taper 24211 is located between the tab connecting portion 233 and the main body portion 241, and the orthographic projection of the connecting end 24211a of another portion of the first sub-taper 24211 in the projection plane perpendicular to the thickness direction X of the wall portion does not overlap with the orthographic projection of the tab connecting portion 233 in the projection plane perpendicular to the thickness direction X of the wall portion.

[0316] In this embodiment, by setting the orthographic projection of at least a portion of the first sub-tab 24211a in the projection plane perpendicular to the thickness direction X of the wall portion into a structure located within the orthographic projection of the tab connection portion 233 in the projection plane perpendicular to the thickness direction X of the wall portion, the portion of the first sub-tab 24211 has more of its parts or even the whole structure located between the tab connection portion 233 and the main body portion 241. The battery cell 20 with this structure can, on the one hand, improve the separation effect of the first tab 242 between the tab connection portion 233 and the main body portion 241, thereby reducing the risk of the tab connection portion 233 and the first tab 242 burning or damaging the main body portion 241 during the welding and assembly process. On the other hand, it can optimize the overall layout of the tab connection portion 233 and the first tab 242, thereby improving the internal space utilization of the battery cell 20 and improving the energy density of the battery cell 20.

[0317] According to some embodiments of this application, in embodiments where multiple first sub-tabs 24211 connected to the first solder mark 25 are stacked on the side of the tab connection portion 233 facing the main body portion 241, combined with Figure 7 and Figure 16 As shown, 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 is 5mm-40mm.

[0318] 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.

[0319] 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 first direction Y (e.g.) Figure 7 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 thickness direction X of the wall portion, 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.

[0320] 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.

[0321] It should be noted that in embodiments where multiple first sub-tabs 24211 connected to the first solder mark 25 are stacked on the side of the tab connection portion 233 facing the main body portion 241, the extension dimension of the sub-tab 2421 from the end connected to the first pole segment 2411a to the end away from the first pole segment 2411a can be made smaller to save space. Therefore, in some embodiments, the extension dimension of the sub-tab 2421 from the end connected to the first pole segment 2411a to the end away from the first pole segment 2411a can be 15mm-20mm.

[0322] In this embodiment, when multiple first sub-taper 24211s connected to the first solder mark 25 are stacked on the side of the electrode connecting portion 233 facing the main body portion 241, on the one hand, the extension dimension of the sub-taper 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, so as to reduce the difficulty of bending multiple sub-taper 2421s toward the first direction Y, and to reduce the difficulty of stacking and welding multiple sub-taper 2421s with the electrode connecting portion 233 after bending, and also to increase the area where the sub-taper 2421s can be stacked and welded with the electrode connecting portion 233 after bending. On the other hand, since the first electrode 24211s are stacked on the side of the main body portion 241, the extension dimension of the sub-taper 2421s 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, so as to reduce the difficulty of bending multiple sub-taper 2421s to the electrode connecting portion 233 after bending, so as to reduce the difficulty of stacking and welding multiple sub-taper 2421s with .... The multiple sub-tabs 2421 of the first electrode 242 are not fixed to each other before welding and assembling with the electrode connection part 233. This allows the multiple sub-tabs 2421 to have the ability to move and shift relative to each other during the process of smoothing and bending the first electrode 242. By setting the extension dimension of the sub-tabs 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-tabs 2421 after bending can be effectively alleviated. This is to optimize the space occupied by the first electrode 242 as a whole in the thickness direction X of the wall, 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.

[0323] According to some embodiments of this application, in an embodiment where multiple first sub-tabs 24211 connected to the first solder mark 25 are stacked on the side of the tab connection portion 233 facing the main body portion 241, see [reference needed]. Figure 16 As shown, along the thickness direction X of the wall, the thickness of the tab connection 233 is 0.2mm-4mm.

[0324] Among them, Figure 16 In the process, the thickness of the tab connecting portion 233 in the thickness direction X of the wall portion is T2. For example, the thickness T2 of the tab connecting portion 233 in the thickness direction X of the wall portion can be any one of the following values ​​or a range between any two: 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, 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.

[0325] It should be noted that in embodiments where multiple first sub-tabs 24211 connected to the first solder mark 25 are stacked on the side of the tab connecting portion 233 facing the main body portion 241, since the first solder mark 25 needs to pass through the tab connecting portion 233 before connecting to the first tab 242, the thickness of the tab connecting portion 233 in the thickness direction X of the wall portion can be set to be smaller. In some embodiments, the thickness of the tab connecting portion 233 in the thickness direction X of the wall portion can be 0.3mm-1mm.

[0326] In this embodiment, when multiple first sub-tabs 24211 connected to the first solder mark 25 are stacked on the side of the tab connecting portion 233 facing the main body 241, the thickness of the tab connecting portion 233 in the wall thickness direction X is set to be greater than or equal to 0.2mm to improve the structural strength of the tab connecting portion 233. This can alleviate the deformation or warping of the tab connecting portion 233 caused by the clamping or pressing of the tooling fixture during the welding assembly process, thereby reducing the gap between the tab connecting portion 233 and the first tab 242 and multiple tabs 242. The welding gap generated between the first tabs 24211 during the welding assembly process helps to reduce the risk of incomplete welding. On the other hand, setting the thickness of the tab connection part 233 in the thickness direction X of the wall to less than or equal to 4mm can alleviate the phenomenon that the tab connection part 233 occupies too much space in the thickness direction X of the wall, which helps to improve the internal space utilization of the battery cell 20 and can reduce the difficulty of the first soldering part 25 passing through the tab connection part 233 and then connecting the first tab 242, which helps to reduce the welding difficulty between the tab connection part 233 and the first tab 242.

[0327] According to some embodiments of this application, refer to Figure 17 , Figure 18 and Figure 19 As shown, Figure 17 Exploded views of the structure of the battery cell 20 provided in some embodiments of this application are also included. Figure 18 This application also provides schematic diagrams of the structure of the electrode assembly 24 of the battery cell 20 in some embodiments. Figure 19 The present application also provides a front view of the electrode assembly 24 of the battery cell 20 in the first direction Y according to some embodiments. The electrode assembly 24 includes 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 portion 241 facing the wall portion 211 and are spaced apart along the second direction Z. The plurality of first tabs 242 are all welded to the tab connecting portion 233 to form a first solder mark portion 25. The thickness direction X of the wall portion, the first direction Y and the second direction Z are perpendicular to each other.

[0328] In this embodiment, multiple first tabs 242 are welded to tab connection portions 233 to form first solder marks 25. This can be a structure in which multiple first tabs 242 are welded to the tab connection portions 233 of the same first current collector 23, or a structure in which each first tab 242 is welded to the tab connection portion 233 of a 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 a 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.

[0329] As an example, in Figure 17 and Figure 18 In this configuration, multiple first tabs 242 are welded and assembled to the tab connection portion 233 of 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 tab connection portion 233 to form first solder marks 25. It should be noted that the multiple first tabs 242 are arranged at intervals along the second 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 second direction Z, or a structure where the first electrode terminal 22 has first tabs 242 on both sides in the second direction Z, or a structure where at least some of the multiple first tabs 242 and the first electrode terminal 22 are arranged in the thickness direction X of the wall.

[0330] In this embodiment, by providing a plurality of first tabs 242 arranged at intervals along the second direction Z and having the same polarity at one end of the main body 241 facing the wall 211, and by welding the plurality of first tabs 242 to the tab connection portion 233 to form a first solder mark portion 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 tab connection portion 233, thereby improving the current flow effect between the main body 241 and the tab connection portion 233; on the other hand, when some of the first tabs 242 have unstable connection or connection failure with the tab connection portion 233, the remaining first tabs 242 can still achieve electrical connection between the main body 241 and the tab connection portion 233, thereby effectively improving the stability and service life of the battery cell 20.

[0331] According to some embodiments of this application, refer to Figure 5 and Figure 8 as well as Figure 17Please refer to further details. Figure 20 , Figure 20 This application also provides a schematic diagram of the structure of the first current collector 23 of the battery cell 20 in some embodiments. The tab connection portion 233 has a bent portion 232 connected to the area corresponding to the first electrode terminal 22 in the thickness direction X of the wall portion, and the bent portion 232 is connected to one end of the tab connection portion 233 in the first direction Y.

[0332] In this embodiment, the tab connecting portion 233 has a bent portion 232 connected to the area corresponding to the first electrode terminal 22 in the thickness direction X of the wall portion. That is, part of the tab connecting portion 233 is located between the first electrode terminal 22 and the main body portion 241 in the thickness direction X of the wall portion, and the bent portion 232 is connected to the part of the tab connecting portion 233 located between the first electrode terminal 22 and the main body portion 241. In this embodiment, if the first electrode terminal 22 is provided with first tabs 242 on both sides in the second direction Z, the bent portion 232 and the terminal connecting portion 231 are located between the two first tabs 242 adjacent to the first electrode terminal 22 in the second direction Z.

[0333] The bending portion 232 is connected to one end of the tab connection portion 233 in the first direction Y. That is, the bending portion 232 is a structure that is connected to the edge of one end of the tab connection portion 233 in the first direction Y. Correspondingly, the bending portion 232 is also connected to one end of the terminal connection portion 231 in the first direction Y, so that the terminal connection portion 231 and the tab connection portion 233 are connected at the same end in the first direction Y through the bending portion 232.

[0334] It should be noted that, in Figure 5 and Figure 8 In the illustrated embodiment, the electrode assembly 24 is provided with only one first tab 242. Correspondingly, the bent portion 232 can be connected to one end of the tab connecting portion 233 in the first direction Y, or it can be connected to one end of the tab connecting portion 233 in the second direction Z. Figure 17 and Figure 18 In the illustrated embodiment, the electrode assembly 24 is provided with a plurality of first tabs 242 arranged at intervals along the second direction Z. The plurality of first tabs 242 are all welded to the tab connection portion 233 of the same first current collector 23. If the plurality of first tabs 242 are all located on the same side of the first electrode terminal 22 in the second direction Z, the bending portion 232 can be connected to one end of the tab connection portion 233 in the first direction Y, or it can be connected to one end of the tab connection portion 233 in the second direction Z. If the first electrode terminal 22 is provided with second tabs 243 on both sides in the second direction Z, the bending portion 232 is a structure connected to one end of the tab connection portion 233 in the first direction Y.

[0335] In this embodiment, by connecting the bent portion 232 to one end of the area where the tab connection portion 233 and the first electrode terminal 22 are respectively disposed in the first direction Y, the interference between the bent portion 232 and the multiple first tabs 242 arranged in the second direction Z can be reduced. On the other hand, the molding difficulty of the tab connection portion 233, the bent portion 232 and the terminal connection portion 231 of the first current collector 23 can be reduced, thereby reducing the manufacturing difficulty of the battery cell 20. Furthermore, the size of the bent portion 232 from one end connected to the tab connection portion 233 to one end connected to the terminal connection portion 231 can be optimized, thereby saving the manufacturing materials and manufacturing cost of the first current collector 23.

[0336] According to some embodiments of this application, see Figure 17 and Figure 18 As shown, along the second direction Z, at least one of the plurality of first tabs 242 is located on one side of the first electrode terminal 22, and at least one first tab 242 is located on the other side of the first electrode terminal 22. That is, the first tabs 242 and the first electrode terminal 22 are arranged along the second direction Z, and the first electrode terminal 22 is provided with first tabs 242 on both sides of the second direction Z.

[0337] Optionally, the number of first tabs 242 connected to the end of the main body 241 of the electrode assembly 24 facing the wall 211 can be two, three, four or more.

[0338] As an example, the electrode assembly 24 includes two first tabs 242. Along the second direction Z, the two first tabs 242 are respectively located on both sides of the first electrode terminal 22. Correspondingly, the first electrode terminal 22 is located between the two first tabs 242 in the second direction Z. See also... Figure 20 As shown, the tab connection portion 233 includes a first connection area 2331 and two second connection areas 2332 arranged along the second direction Z. The two second connection areas 2332 are respectively connected to the two ends of the first connection area 2331 in the second direction Z. The first connection area 2331 is located between the first electrode terminal 22 and the main body portion 241. The terminal connection portion 231 is connected to one end of the first connection area 2331 in the first direction Y through a bending portion 232. The two first tabs 242 are respectively welded to the two second connection areas 2332 to form a first solder mark portion 25. That is, the first solder mark portion 25 connects the first tab 242 and the second connection area 2332 of the tab connection portion 233.

[0339] In this embodiment, a portion of the first tabs 242 are located on one side of the first electrode terminal 22 in the second direction Z, and another portion of the first tabs 242 are located on the other side of the first electrode terminal 22 in the second direction Z. This results in the first electrode terminal 22 having first tabs 242 on both sides in the second direction Z, and the first electrode terminal 22 being positioned between two adjacent first tabs 242 in the second direction Z. This structure in the battery cell 20 optimizes both the first electrode terminal 22 and the multiple first tabs 242. The layout between them allows the first electrode terminal 22 and the first tab 242 to share space in the thickness direction X of the wall. On the other hand, it enables the multiple first tabs 242 to be structured so that the current flows from both sides of the first electrode terminal 22 in the second direction Z through the tab connection part 233. This shortens the current path between the multiple first tabs 242 as a whole and the first electrode terminal 22, which is beneficial to reducing the internal resistance of the battery cell 20 and reducing the current flow area requirement of the tab connection part 233, thereby optimizing the thickness of the tab connection part 233.

[0340] In some embodiments, see Figure 19 As shown, along the second direction Z, the minimum distance between the first tab 242 located on one side of the first electrode terminal 22 and the first tab 242 located on the other side of the first electrode terminal 22 is 20mm-50mm.

[0341] Among them, Figure 19 In the first electrode terminal 22, the minimum distance between two first electrode tabs 242 located on both sides of the first electrode terminal 22 and adjacent to the first electrode terminal 22 is D, i.e., 20mm≤D≤50mm. For example, the minimum distance D between two first electrode tabs 242 located on both sides of the first electrode terminal 22 and adjacent to the first electrode terminal 22 can be any one of the following values ​​or a range between any two: 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 26mm, 27mm, 28mm, 29mm, 30mm, 31mm, 32mm, 33mm, 34mm, 35mm, 36mm, 37mm, 38mm, 39mm, 40mm, 41mm, 42mm, 43mm, 44mm, 45mm, 46mm, 47mm, 48mm, 49mm, or 50mm.

[0342] As an example, the electrode assembly 24 includes two first tabs 242 along the second direction Z. The two first tabs 242 are located on both sides of the first electrode terminal 22. Correspondingly, the minimum distance between the two first tabs 242 in the second direction Z is 20mm-50mm.

[0343] In this embodiment, on the one hand, the minimum distance between two first tabs 242 located on both sides of the first electrode terminal 22 and adjacent to the first electrode terminal 22 in the second direction Z is set to be greater than or equal to 20mm, so as to facilitate the placement of the first electrode terminal 22 between two adjacent first tabs 242 and reduce the interference between the first electrode terminal 22 and the first tabs 242. On the other hand, the minimum distance between two first tabs 242 located on both sides of the first electrode terminal 22 and adjacent to the first electrode terminal 22 in the second direction Z is set to be less than or equal to 50mm, so as to save the space occupied by the two first tabs 242 adjacent to the first electrode terminal 22 in the second direction Z, thereby optimizing the spatial layout of multiple first tabs 242 in the second direction Z.

[0344] According to some embodiments of this application, in conjunction with Figure 6 and Figure 18 As shown, each first electrode tab 242 has multiple sub-electrode tabs 2421, each of which is fixedly connected to the first solder mark portion 25. Along the thickness direction X of the wall portion, the portions of the multiple first sub-electrode tabs 24211 connected to the first solder mark portion 25 are stacked on one side of the electrode tab connection portion 233. In the first direction Y, the bending direction of the first sub-electrode tab 24211 of one first electrode tab 242 is opposite to the bending direction of the first sub-electrode tab 24211 of another first electrode tab 242.

[0345] In the first direction Y, the bending direction of the first sub-taper 24211 of one first electrode 242 is opposite to the bending direction of the first sub-taper 24211 of the other first electrode 242. That is, in the first direction Y, the first sub-taper 24211 of one first electrode 242 bends toward one side of the main body 241, while the first sub-taper 24211 of the other first electrode 242 bends toward the other side of the main body 241, so that at least two of the multiple first electrodes 242 have opposite bending directions. In an embodiment where the portion of the first sub-taper 24211 fixedly connected to the first solder mark 25 is located on the side of the tab connection portion 233 facing away from the main body portion 241, then the first sub-taper 24211 of one first tab 242 has a structure that bends from one side of the tab connection portion 233 in the first direction Y and extends to the side of the tab connection portion 233 facing away from the main body portion 241, and the first sub-taper 24211 of the other first tab 242 has a structure that bends from the other side of the tab connection portion 233 in the first direction Y and extends to the side of the tab connection portion 233 facing away from the main body portion 241. The structure on one side of 41, that is, at least two first tabs 242, are respectively smoothed and bent from both sides of the tab connection portion 233 in the first direction Y to the side of the tab connection portion 233 away from the main body portion 241; if the part of the first sub-tab 24211 fixedly connected to the first solder part 25 is located on the side of the tab connection portion 233 facing the main body portion 241, then the first sub-tab 24211 of one first tab 242 and the first sub-tab 24211 of the other first tab 242 are bent in opposite directions in the first direction Y.

[0346] It should be noted that in embodiments where multiple first sub-taps 24211 connected to the first solder mark 25 are stacked on the side of the tab connection portion 233 away from the main body portion 241 (i.e., multiple first sub-taps 24211 connected to the first solder mark 25 are stacked between the tab connection portion 233 and the terminal connection portion 231), and the orthographic projection of the connection ends 24211a of all the first sub-taps 24211 in the projection plane perpendicular to the thickness direction X of the wall portion does not overlap with the orthographic projection of the tab connection portion 233 in the projection plane perpendicular to the thickness direction X of the wall portion, such as... Figure 15As shown, the multiple sub-tabs 2421 in the same first electrode tab 242 are connected only to a portion of the multiple first electrode segments 2411a. That is, each first sub-tab 24211 is only connected to a portion of the multiple first electrode segments 2411a. If the electrode assembly 24 is a wound structure, the first electrode segments 2411a not connected to the sub-tabs 2421 can be guided through the first bending section 2411b and other first electrode segments 2411a. Correspondingly, the first electrode tabs 242 connected to the main body 241 can be one or multiple, and can be a structure in which the smoothing and bending directions of the multiple first electrode tabs 242 are all the same, or... If the electrode assembly 24 has a stacked structure with at least two first electrode tabs 242 having opposite smoothing and bending directions, then the first electrode segment 2411a without connected sub-electrode tabs 2421 cannot conduct current, resulting in the failure of some first electrode segments 2411a. Therefore, the main body 241 has multiple first electrode tabs 242 connected to it, and at least two first electrode tabs 242 have opposite smoothing and bending directions. That is, in the first direction Y, the bending direction of the first sub-electrode tab 24211 of one first electrode tab 242 is opposite to the bending direction of the first sub-electrode tab 24211 of another first electrode tab 242. Correspondingly, each first electrode segment 2411a is connected to at least one first sub-electrode tab 24211.

[0347] It should be noted that in embodiments where multiple first sub-tabs 24211 connected to the first solder mark 25 are stacked on the side of the tab connection portion 233 facing the main body portion 241, such as... Figure 16As shown, among the multiple sub-taps 2421 of the same first electrode tab 242, at least one sub-taps 2421 located on one side of the multiple first sub-taps 24211 in the bending direction of the first sub-taps 24211 has a structure that is not connected to the first solder mark portion 25. In this structure, if the same first electrode tab 242 is connected to multiple first electrode segments 2411a, then the multiple sub-taps 2421 of the same first electrode tab 242 includes a second sub-taps 24212, that is, at least one sub-taps among the multiple sub-taps 2421 of the same first electrode tab 242. 2421 is not connected to the first solder mark 25. Conversely, if multiple sub-tabs 2421 of the same first electrode tab 242 are all connected to the first solder mark 25, then the portion of the multiple first electrode segments 2411a located on one side of the first sub-tab 24211 in the bending direction of the first sub-tab 24211 is not connected to the sub-tab 2421. That is to say, in both cases, at least one first electrode segment 2411a is not fixedly connected to the first solder mark 25 through the sub-tab 2421. Therefore, if the electrode assembly 24 is a wound structure... If the first electrode segment 2411a is not fixedly connected to the first solder joint 25 via the sub-electrode tab 2421, the current can be conducted through the first bent section 2411b and other first electrode segments 2411a. Correspondingly, the first electrode tab 242 connected to the main body 241 can be one or more, and can be a structure in which the smoothing and bending directions of multiple first electrode tabs 242 are all the same, or a structure in which the smoothing and bending directions of at least two first electrode tabs 242 are opposite. If the electrode assembly 24 is a stacked structure, the first electrode segment 2411a not fixedly connected to the first solder joint 25 via the sub-electrode tab 2421 can be conducted through the first bent section 2411b and other first electrode segments 2411a. The first pole segment 2411a of the fixed connection cannot conduct current, and there is a phenomenon of partial failure of the first pole segment 2411a. Therefore, there are multiple first pole ears 242 connected on the main body 241, and at least two first pole ears 242 have a structure with opposite smoothing and bending directions. That is, in the first direction Y, the bending direction of the first sub-pole ear 24211 of one first pole ear 242 is opposite to the bending direction of the first sub-pole ear 24211 of another first pole ear 242. Correspondingly, each first pole segment 2411a is connected to at least one first sub-pole ear 24211.

[0348] In this embodiment, by setting the bending direction of the first sub-taper 24211 of one first electrode tab 242 in the first direction Y and the bending direction of the first sub-taper 24211 of another first electrode tab 242 in the first direction Y to be opposite, the smoothing bending directions of at least two first electrodes tabs 242 are opposite. Using this structure, the battery cell 20 can achieve a structure where the stacking order of the multiple first sub-taper 24211s of at least two first electrodes tabs 242 welded to the electrode connection portion 233 is opposite. Since the multiple first electrodes tabs 242 and the electrode connection portion 233 are all welded and assembled on the same side, even if each first... When a portion of the first sub-taps 24211 near the welding side of the electrode tab 242 is damaged, the damaged first sub-taps 24211 in two first electrodes 242 with opposite bending directions can be smoothed out. These damaged first sub-taps 24211 are connected to different first electrode segments 2411a. This ensures that at least one of the multiple first sub-taps 24211 connected to the first electrode segment 2411a is not damaged, thus still satisfying the electrical connection between the corresponding first electrode segment 2411a and the first current collector 23. This is beneficial to improving the overall stability and service life of the battery cell 20.

[0349] According to some embodiments of this application, in conjunction with Figure 7 and Figure 10 As shown, in an embodiment where the electrode assembly 24 has a stacked structure, the main body 241 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 have opposite polarities, and the first electrode plates 2411 and the second electrode plates 2412 are alternately stacked along the first direction Y. Correspondingly, the first electrode plate 2411 is a first electrode segment 2411a, and each first electrode segment 2411a is connected to a first sub-electrode tab 24211 at one end near the wall portion 211 in the thickness direction X of the wall portion. That is, each first electrode segment 2411a in the stacked electrode assembly 24 is connected to at least one sub-electrode tab 2421 at one end near the wall portion 211 in the thickness direction X of the wall portion, and at least one sub-electrode tab 2421 on each first electrode segment 2411a is fixedly connected to the first solder mark portion 25.

[0350] In this embodiment, the electrode assembly 24 has a stacked structure, so that the first electrode 2411 of the main body 241 is a whole first electrode segment 2411a. Thus, by connecting at least one first sub-electrode tab 24211 to each first electrode segment 2411a, each first electrode 2411 of the main body 241 can be electrically connected to the first current collector 23, thereby reducing the risk of failure of some first electrode 2411 of the electrode assembly 24. In the structure where the flattening and bending directions of at least two first electrodes 242 are opposite, it is convenient for the electrode tab connection part 233 to be welded to different first electrodes 242, so that at least one sub-electrode tab 2421 on each first electrode segment 2411a can be welded to the first current collector 23. This helps to reduce the difficulty of providing a first sub-electrode tab 24211 on each first electrode segment 2411a.

[0351] According to some embodiments of this application, this application also provides a battery device 100, which includes a battery cell 20 of any of the above schemes.

[0352] Among them, see Figure 2 As shown, the battery device 100 may also include a housing 10, in which the battery cells 20 are housed.

[0353] In some embodiments, the housing 10 may include a first housing body 11 and a second housing body 12, the first housing body 11 and the second housing body 12 covering each other, the first housing body 11 and the second housing body 12 together defining an assembly space for accommodating the battery cell 20.

[0354] Optionally, the second box body 12 can be a hollow structure with one end open, and the first box body 11 can be a plate-like structure. The first box body 11 covers the open side of the second box body 12 so that the first box body 11 and the second box body 12 together define the assembly space; the first box body 11 and the second box body 12 can also be hollow structures with one side open, and the open side of the first box body 11 covers the open side of the second box body 12.

[0355] Of course, the box 10 formed by the first box body 11 and the second box body 12 can be of various shapes, such as a cylinder or a cuboid. For example, in... Figure 2 In the middle, box 10 has a rectangular structure.

[0356] Optionally, the battery cell 20 disposed within the housing 10 can be one or more. For example, in... Figure 2In the battery device 100, multiple battery cells 20 are arranged inside the housing 10. The multiple battery cells 20 can be connected in series, parallel, or in a mixed manner. A mixed connection means that the multiple battery cells 20 are connected in both series and parallel. The multiple battery cells 20 can be directly connected in series, parallel, or in a mixed manner, and then the whole assembly of the multiple battery cells 20 is housed in the housing 10. Of course, the battery device 100 can also be formed by first connecting multiple battery cells 20 in series, parallel, or in a mixed manner to form a battery module, and then connecting multiple battery modules in series, parallel, or in a mixed manner to form a whole assembly, which is also housed in the housing 10.

[0357] The battery device 100 may also include other structures. For example, the battery device 100 may also include a busbar component that connects multiple battery cells 20 to achieve electrical connection between the multiple battery cells 20.

[0358] It should be noted that in some embodiments, the battery device 100 may not have a housing 10. The battery device 100 includes multiple battery cells 20, and the battery device 100 composed of multiple battery cells 20 can be directly mounted onto the electrical device to provide power to the electrical device through the multiple battery cells 20. That is, the housing 10 can be part of the electrical device. Taking a vehicle 1000 as an example, the housing 10 can be part of the chassis structure of the vehicle 1000. For example, a portion of the housing 10 can be at least a part of the floor of the vehicle 1000, or a portion of the housing 10 can be at least a part of the crossbeams and longitudinal beams of the vehicle 1000.

[0359] According to some embodiments of this application, this application also provides an electrical device, which includes a battery cell 20 of any of the above schemes, and the battery cell 20 is used to provide electrical energy to the electrical device.

[0360] The electrical device can be any of the aforementioned devices or systems that utilize battery cells 20.

[0361] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0362] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A battery cell, characterized in that, include: The outer shell has walls; A first electrode terminal is disposed on the wall portion; At least one electrode assembly is disposed 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 first 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 wall. The sub-electrode tabs are bent toward the first direction, and portions of the plurality of sub-electrode tabs are stacked along the thickness direction of the wall. The first direction is perpendicular to the thickness direction of the wall. A first current collector is located between the main body and the first electrode terminal. 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 in the thickness direction of the wall portion and is welded to the first electrode terminal. The electrode tab connection portion and portions of the first electrode tab are stacked and welded together in the thickness direction of the wall portion to form at least one first solder mark portion. Each first solder mark portion passes through at least a portion of the sub-electrode tab in the thickness direction of the wall portion, and two adjacent sub-electrode tabs are fixedly connected only through the first solder mark portion.

2. The battery cell according to claim 1, characterized in that, The first current collector is a single-layer foil structure, and the thickness of the bent portion is 0.5mm-2mm.

3. The battery cell according to claim 2, characterized in that, The thickness of the tab connection portion is greater than or equal to the thickness of the bent portion; and / or The thickness of the terminal connection portion is greater than or equal to the thickness of the bent portion.

4. The battery cell according to claim 1, characterized in that, The first current collector includes multiple foils, which are stacked and connected together, and the thickness of the portion of each foil located at the bend is 0.05mm-0.1mm.

5. The battery cell according to claim 4, characterized in that, The sum of the thicknesses of the portions of the multiple foils located at the bend is 0.5mm-2mm.

6. The battery cell according to claim 4, characterized in that, The thickness of the foil at the tab connection portion is greater than or equal to the thickness of the foil at the bend portion; and / or The thickness of the foil portion located at the terminal connection is greater than or equal to the thickness of the foil portion located at the bend.

7. The battery cell according to claim 1, characterized in that, The bent portion is provided with a through hole, which penetrates the bent portion along the thickness direction.

8. The battery cell according to claim 1, characterized in that, The terminal connection portion is welded to the first electrode terminal to form a second solder mark portion; Along the thickness direction of the wall portion, the terminal connection portion has a first surface facing away from the first electrode terminal, and at least a portion of the second solder mark portion extends from the first surface into the first electrode terminal.

9. The battery cell according to claim 1, characterized in that, In a projection plane perpendicular to the thickness direction of the wall portion, 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 first direction or the angle between the length direction of the orthographic projection of the first solder mark and the first direction is less than or equal to 30°.

10. The battery cell according to claim 9, characterized in that, The first electrode tab has multiple first solder marks, which are arranged at intervals along the second direction. The thickness direction of the wall, the first direction, and the second direction are perpendicular to each other.

11. The battery cell according to claim 10, characterized in that, The plurality of said sub-tabs include a plurality of first sub-tabs fixedly connected to the first solder pad, and each first sub-tab is fixedly connected to at least two first solder pads.

12. The battery cell according to claim 9, characterized in that, In the projection plane perpendicular to the thickness direction of the wall portion, the width of the orthographic projection of the first solder mark portion in the second direction is 0.5mm-5mm, and the thickness direction of the wall portion, the first direction, and the second direction are perpendicular to each other.

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

1.

14. The battery cell according to any one of claims 1-13, characterized in that, The plurality of said sub-tabs include a plurality of first sub-tabs fixedly connected to the first solder mark portion. Along the thickness direction of the wall portion, the portions of the plurality of first sub-tabs connected to the first solder mark portion are stacked on the side of the tab connection portion away from the main body portion. The first tab has a second surface away from the tab connection portion, and at least a portion of the first solder mark portion extends from the second surface into the tab connection portion.

15. The battery cell according to claim 14, characterized in that, All of the sub-tabs in the first electrode tab are fixedly connected to the first solder mark.

16. The battery cell according to claim 14, characterized in that, Along the thickness direction of the wall portion, the thickness of the portion of the first solder mark extending into the tab connection portion is T1, and the thickness of the tab connection portion is T2, satisfying 0.25≤T1 / T2≤0.

75.

17. The battery cell according to claim 14, 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.

18. The battery cell according to claim 14, characterized in that, Along the thickness direction of the wall portion, the thickness of the electrode connecting portion is 0.3mm-4mm.

19. The battery cell according to claim 14, characterized in that, The first sub-electrode has a connecting end connected to the first pole segment. In a projection plane perpendicular to the thickness direction of the wall portion, at least a portion of the orthographic projection of the connecting end of the first sub-electrode is located within the orthographic projection of the pole connection portion, and the first sub-electrode, whose orthographic projection of the connecting end is located within the orthographic projection of the pole connection portion, bends around the pole connection portion.

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

21. The battery cell according to claim 14, characterized in that, The first sub-taper has a connecting end connected to the first pole segment. In a projection plane perpendicular to the thickness direction of the wall, the orthographic projection of the connecting portion of the pole piece does not overlap with the orthographic projection of the connecting ends of all the first sub-tapers.

22. The battery cell according to claim 14, characterized in that, The battery cell also includes: A heat insulation component is disposed at least partially between the tab connection portion and the main body portion in the thickness direction of the wall portion, and at least a portion of the orthographic projection of the first solder mark portion is located within the orthographic projection of the heat insulation component in a projection plane perpendicular to the thickness direction of the wall portion.

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

24. The battery cell according to claim 22, characterized in that, The heat insulation component is made of insulating material.

25. The battery cell according to claim 22, characterized in that, The heat insulation component is connected to the surface of the electrode connection portion facing the main body.

26. The battery cell according to claim 14, characterized in that, The battery cell also includes: The support member is supported between the tab connection portion and the main body portion along the thickness direction of the wall portion, 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 thickness direction of the wall portion.

27. The battery cell according to any one of claims 1-13, characterized in that, The plurality of said sub-tabs include a plurality of first sub-tabs fixedly connected to the first solder mark portion. Along the thickness direction of the wall portion, the portions of the plurality of first sub-tabs connected to the first solder mark portion are stacked on the side of the tab connection portion facing the main body portion. The tab connection portion has a third surface facing away from the main body portion, and at least a portion of the first solder mark portion extends from the third surface into the first tab.

28. The battery cell according to claim 27, characterized in that, In the bending direction of the first sub-taper, at least one of the multiple sub-tapers located on one side of the multiple first sub-tapers bends around the taper connection and extends to the side of the taper connection away from the main body.

29. The battery cell according to claim 27, characterized in that, All the sub-tabs in the first electrode tab are fixedly connected to the first solder mark portion, and all the sub-tabs in the first electrode tab are located on the side of the electrode tab connection portion facing the main body portion in the thickness direction of the wall portion.

30. The battery cell according to claim 27, characterized in that, In the same first electrode tab, multiple sub-electrodes arranged sequentially from the first to the nth along the bending direction of the first sub-electrode tab are all first sub-electrodes, where n is greater than or equal to 2.

31. The battery cell according to claim 27, characterized in that, The first sub-electrode has a connecting end connected to the first pole segment. In a projection plane perpendicular to the thickness direction of the wall portion, at least a portion of the orthographic projection of the connecting end of the first sub-electrode is located within the orthographic projection of the pole segment connection portion.

32. The battery cell according to claim 27, 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.

33. The battery cell according to claim 27, characterized in that, Along the thickness direction of the wall portion, the thickness of the tab connection portion is 0.2mm-4mm.

34. The battery cell according to any one of claims 1-13, characterized in that, The electrode assembly includes a plurality of first electrode tabs with the same polarity. The plurality of first electrode tabs are all connected to one end of the main body facing the wall and are spaced apart along the second direction. The plurality of first electrode tabs are all welded to the electrode tab connecting part to form the first solder mark. The thickness direction of the wall, the first direction and the second direction are perpendicular to each other.

35. The battery cell according to claim 34, characterized in that, The tab connection portion is connected to the bending portion in the region corresponding to the first electrode terminal in the thickness direction of the wall portion, and the bending portion is connected to one end of the tab connection portion in the first direction.

36. The battery cell according to claim 34, characterized in that, Along the second direction, at least one of the plurality of first tabs is located on one side of the first electrode terminal, and at least one of the first tabs is located on the other side of the first electrode terminal.

37. The battery cell according to claim 36, characterized in that, Along the second direction, the minimum distance between the first tab on one side of the first electrode terminal and the first tab on the other side of the first electrode terminal is 20mm-50mm.

38. The battery cell according to claim 34, characterized in that, Each of the multiple sub-tabs of the first electrode tab includes multiple first sub-tabs fixedly connected to the first soldering portion. Along the thickness direction of the wall portion, the portions of the multiple first sub-tabs connected to the first soldering portion are stacked on one side of the electrode tab connection portion. In the first direction, the bending direction of the first sub-taper of one first electrode is opposite to the bending direction of the first sub-taper of the other first electrode.

39. The battery cell according to claim 38, 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 first direction. The first electrode is the first electrode segment, and each first electrode segment is connected to the first sub-electrode tab at one end near the wall in the thickness direction of the wall.

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

41. An electrical appliance, characterized in that, Includes a battery cell as described in any one of claims 1-39, the battery cell being used to provide electrical energy.

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