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 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, each sub-tab is connected to one end of a first pole segment close to a wall part, the sub-tabs are bent towards the first direction, and parts of the plurality of sub-tabs are stacked between the main body part and the first electrode terminal along the thickness direction of the wall part. The first electrode terminal and the first tab are welded to form a welding mark part, the welding mark part passes through at least part of the sub-tabs, and two adjacent sub-tabs are fixedly connected only through the welding mark part. The outer surface of the first electrode terminal away from the main body part comprises a first surface, and at least part of the welding mark part extends from the first surface into the first tab, so as to reduce the damage of the sub-tabs and the assembly difficulty of the first tab and the first electrode terminal.

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 housing, a first electrode terminal, and at least one electrode assembly; the housing has a wall portion; the first electrode terminal is disposed on the wall portion; the electrode assembly is housed within the housing, the electrode assembly includes a main body portion and a first electrode tab, the main body portion 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 being connected to one end of a first electrode segment near the wall portion, the sub-electrode tabs being bent toward the first direction, and portions of the plurality of sub-electrode tabs being stacked between the main body portion and the first electrode terminal along the thickness direction of the wall portion, the first direction being perpendicular to the wall portion. In the thickness direction; the first electrode terminal and the first electrode tab are welded together to form at least one solder mark, each solder mark passing through at least a portion of the sub-electrode tab along the thickness direction of the wall portion, two adjacent sub-electrode tabs being fixedly connected only through the solder mark, each first electrode tab having a plurality of sub-electrode tabs fixedly connected to the solder mark, in the first direction, the bending direction of the plurality of first sub-electrode tabs of the same first electrode tab is the same, along the thickness direction of the wall portion, the outer surface of the first electrode terminal away from the main body portion includes a first surface, at least a portion of the solder mark extends from the first surface into the first electrode tab, and the orthographic projection of the solder mark in a projection plane perpendicular to the thickness direction of the wall portion is strip-shaped.

[0006] In the above technical solution, the first electrode tab 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 first electrode terminal to form a solder mark, thereby realizing the assembly connection between the first electrode tab and the first electrode terminal. Each 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 solder mark. This ensures that after the first electrode tab is bent toward the first direction and before the first electrode tab is stacked and welded to the first electrode terminal, the multiple sub-electrodes of the first electrode tab are not fixedly connected or pre-welded, so that the multiple sub-electrodes of the first electrode tab can be smoothed and bent before the first electrode terminal is assembled. The first tab and the first electrode terminal are welded together, allowing multiple sub-tabs to move and shift relative to each other during the smoothing and bending process of the first tab. This enables each sub-tab to adapt to the length changes caused by bending, reducing local stress concentration or bulging during the smoothing and bending process. This effectively improves the welding quality between the first tab and the first electrode terminal 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 electrode terminal during use, thus improving the stability and reliability of the battery cell. Furthermore, by configuring at least a portion of the weld mark formed by welding the first tab and the first electrode terminal together as extending from the first surface of the first electrode terminal away from the main body into the first tab, the welding assembly between the first tab and the first electrode terminal is configured as a structure in which the first electrode terminal and the first tab are directly welded in the thickness direction of the wall from the side of the first electrode terminal away from the main body. This enables a direct current flow structure between the first tab and the first electrode terminal, which is beneficial to improving the current flow effect between the first electrode terminal and the electrode assembly, thereby reducing the internal resistance of the battery cell. It also helps to optimize the internal layout of the battery cell and improve the internal space utilization of the battery cell, thereby increasing the energy density of the battery cell. On the other hand, since the gap between the first tab and the main body is too small after the first tab is flattened and bent, this assembly structure can reduce the welding difficulty between the first tab and the first electrode terminal and reduce the phenomenon of welding slag and other particles generated by welding the first tab and the first electrode terminal falling into the casing, thereby reducing the risk of internal short circuits in the battery cell during use. In addition, by setting multiple first sub-tabs of the same first electrode tab to a structure in which the bending direction is the same in the first direction, the soldering part can be fixedly connected to multiple first sub-tabs. Furthermore, by setting the orthographic projection of the soldering part in the projection plane perpendicular to the thickness direction of the wall to a strip-shaped structure, the soldering part can be connected to more sub-tabs to improve the overcurrent effect between the first electrode tab and the first electrode terminal.

[0007] In some embodiments, in a projection plane perpendicular to the thickness direction of the wall portion, the orthographic projection of the solder mark is a strip structure extending along a straight trajectory, and the length direction of the orthographic projection of the solder mark is parallel to the first direction or the angle between the length direction of the orthographic projection of the solder mark and the first direction is less than or equal to 30°.

[0008] 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 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 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 solder part and the first direction is less than or equal to 30°, it is possible to further connect the solder part with more sub-electrode tabs, thereby further improving the overcurrent effect between the first electrode tab and the first electrode terminal, and further improving the connection stability between the first electrode tab and the first electrode terminal.

[0009] In some embodiments, there are multiple solder marks on the first tab, and the multiple 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.

[0010] In the above technical solution, by setting multiple solder marks on the first tab, and the multiple solder marks being arranged at intervals along the second direction, so that the orthographic projection of the multiple 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 first electrode terminal, thereby further improving the overcurrent effect between the first tab and the first electrode terminal, and further improving the connection stability between the first tab and the first electrode terminal. On the other hand, even if there is a connection failure between the sub-tab and some solder marks, the multiple solder marks can ensure that the sub-tab can still maintain the connection with the first electrode terminal through the remaining solder marks, thereby improving the fault tolerance rate of the welding assembly between the sub-tab and the first electrode terminal, and improving the electrical connection stability between the sub-tab and the first electrode terminal, so as to reduce the risk of connection failure between the sub-tab and the first electrode terminal.

[0011] In some embodiments, each of the first sub-tabs is fixedly connected to at least two of the solder pads.

[0012] In the above technical solution, by fixing each first sub-tab to at least two solder marks, each first sub-tab that is welded to the first electrode terminal is passed through by at least two solder marks. On the one hand, this can increase the current flow area and current flow path between the first sub-tab and the first electrode terminal. On the other hand, it can still be electrically connected to the first electrode terminal through other solder marks even if the connection between the first sub-tab and one or more solder marks fails, which is beneficial to improving the electrical connection stability between the first sub-tab and the first electrode terminal.

[0013] In some embodiments, in a projection plane perpendicular to the thickness direction of the wall portion, the width of the orthographic projection of the solder mark 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.

[0014] In the above technical solution, on the one hand, the width of the orthogonal projection of the 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 solder mark and the first sub-electrode, thereby improving the overcurrent effect between the first sub-electrode and the first electrode terminal, and improving the connection stability between the first sub-electrode and the first electrode terminal. On the other hand, the width of the orthogonal projection of the 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 solder mark formed by the welding of the first electrode terminal and the first sub-electrode is too large, which helps to reduce the power required for welding and assembling the first electrode terminal and the first sub-electrode, and can reduce the area of ​​the first sub-electrode passed through by the solder mark, thereby reducing the risk of damage to the first sub-electrode.

[0015] In some embodiments, the area through which the first sub-tab is pierced by the solder mark forms a solder mark area, the surface area of ​​the first sub-tab on one side in its thickness direction is S1, and the sum of the areas of all the solder marks on the same first sub-tab is S2, satisfying 0.0075≤S2 / S1≤0.1.

[0016] 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 first sub-tab on one side in the thickness direction, so as to increase the welding area between the single first sub-tab and the first electrode terminal, thereby improving the overcurrent effect between the single first sub-tab and the first electrode terminal, and improving the connection stability between the single first sub-tab and the first electrode terminal. 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 first sub-tab on one side in the thickness direction, so as to alleviate the phenomenon that the area through which the first sub-tab is penetrated by the solder part is too large, thereby reducing the welding difficulty between the single first sub-tab and the first electrode terminal, and reducing the power required for welding and assembling the first electrode terminal and the first tab.

[0017] 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.

[0018] In the above technical solution, on the one hand, the extension dimension of the sub-tab from one end connected to the first electrode segment to the end away from the first electrode segment is set to be greater than or equal to 5mm, so as to reduce the difficulty of bending multiple sub-tabs in the first direction, and also reduce the difficulty of stacking and welding multiple sub-tabs with the first electrode terminal after bending. It is also beneficial to increase the area where the sub-tabs can be stacked and welded with the first electrode terminal after bending. On the other hand, since the multiple sub-tabs of the first electrode segment are not fixed to each other before welding and assembling with the first electrode terminal, the multiple sub-tabs can have the ability to move and shift relative to each other during the process of smoothing and bending the first electrode segment. Thus, by setting the extension dimension of the sub-tab from one end connected to the first electrode segment to the end away from the first electrode segment to be less than or equal to 40mm, the phenomenon of redundancy or local bulging of the sub-tabs after bending can be effectively alleviated, so as to optimize the space occupied by the first electrode segment in the thickness direction of the wall, which is beneficial to improve the internal space utilization of the battery cell, and thus improve the energy density of the battery cell.

[0019] In some embodiments, the first sub-tab 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-tab lies within the orthographic projection of the solder mark portion.

[0020] In the above technical solution, by setting the orthographic projection of at least a portion of the first sub-tab's 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 solder portion in the projection plane perpendicular to the thickness direction of the wall portion, the first sub-tab has a structure in which more or even the entire portion is located between the solder 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 first electrode terminal and the main body portion, thereby reducing the risk of the first electrode terminal and the first tab being burned or damaged during the welding and assembly process. On the other hand, it can realize the connection of more portions of the solder portion and the first sub-tab, which is beneficial to improving the connection stability and current flow area between the first sub-tab and the first electrode terminal.

[0021] 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.

[0022] 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 first electrode terminal, the welding range between the first electrode terminal and the first electrode tab can be increased, and the soldering part can be fixedly connected to more sub-electrodes, thereby improving the connection stability and overcurrent effect between the first electrode terminal and the first electrode tab.

[0023] In some embodiments, the plurality of sub-tabs further include at least one second sub-tab that is not fixedly connected to the solder mark, all the second sub-tabs being located on one side of the plurality of first sub-tabs in the bending direction of the first sub-tabs, and at least one second sub-tab being partially bent and located on one side of the first electrode terminal in the first direction.

[0024] In the above technical solution, by setting at least one second sub-electrode that is not connected to the soldering part and is located on one side of the multiple first sub-electrode in the bending direction of the first sub-electrode as a structure that bends and extends to one side of the first electrode terminal in the first direction, the overall regularity of the first electrode is improved, which helps to alleviate the phenomenon of the second sub-electrode occupying space or being inserted upside down into the main body.

[0025] In some embodiments, in a projection plane perpendicular to the thickness direction of the wall portion, the orthographic projection of all the second sub-taperes lies within the orthographic projection of the main body portion.

[0026] In the above technical solution, by setting the orthographic projection of all the second sub-electrodes in the projection plane perpendicular to the thickness direction of the wall portion to a structure located in the orthographic projection of the main body portion in the projection plane perpendicular to the thickness direction of the wall portion, the phenomenon of the second sub-electrodes protruding from one side of the main body portion in the first direction can be alleviated, thereby optimizing the space occupied by the electrode assembly in the first direction and reducing the interference between the first electrode and other components.

[0027] In some embodiments, all of the sub-tabs in the first tab are fixedly connected to the solder mark portion.

[0028] In the above technical solution, by fixing all the sub-tabs in the first electrode tab to the soldering part, each sub-tab in the first electrode tab is a structure that is soldered to the first electrode terminal, thereby further improving the overcurrent effect and connection stability between the first electrode tab and the first electrode terminal, and reducing the risk of the overcurrent path of the first electrode segment being too long or the connection failing due to the sub-tabs on some parts of the first electrode segment not being soldered to the first electrode terminal.

[0029] In some embodiments, along the thickness direction of the wall portion, a groove is provided on the side of the first electrode terminal away from the main body portion, the groove wall surface is a part of the outer surface of the first electrode terminal away from the main body portion, and the groove bottom surface is the first surface.

[0030] In the above technical solution, by providing a groove on the side of the first electrode terminal away from the main body, and the bottom surface of the groove being the first surface, the bottom wall of the groove in the first electrode terminal is welded to the first tab to form a welded part. The battery cell with this structure can reduce the thickness of the area of ​​the first electrode terminal used for welding with the first tab, thereby reducing the power required for welding and assembling the first electrode terminal and the first tab, which is beneficial to reducing the welding difficulty between the first electrode terminal and the first tab. On the other hand, it is not necessary to set the first electrode terminal as an overall thinned structure, which is beneficial to reduce the assembly difficulty between the first electrode terminal and the wall while meeting the structural strength of the first electrode terminal.

[0031] In some embodiments, the battery cell further includes a sealing member; the sealing member is connected to the side of the first electrode terminal opposite to the main body portion, and the sealing member seals the groove.

[0032] In the above technical solution, by connecting a sealing component to the first electrode terminal, and the sealing component having a sealing groove structure, the phenomenon of impurities or liquids entering the groove can be reduced during the use of the battery cell. Thus, the sealing component can also provide a certain degree of protection for the soldering part, thereby reducing the risk of the soldering part being worn or corroded and rusted during use.

[0033] In some embodiments, the electrode assembly includes a plurality of first tabs with the same polarity, each of the plurality of first tabs being connected to one end of the main body facing the wall portion, the plurality of first tabs being spaced apart along a second direction, and each of the plurality of first tabs being welded to the first electrode terminal and forming the solder mark portion, wherein the thickness direction of the wall portion, the first direction, and the second direction are perpendicular to each other.

[0034] In the above technical solution, by providing a plurality of first tabs arranged at intervals along the second direction and having the same polarity at one end of the main body facing the wall, and by welding the plurality of first tabs to the first electrode terminal to form a solder mark, the battery cell with this structure can, on the one hand, increase the current flow area and current flow path between the main body and the first electrode terminal, thereby improving the current flow effect between the main body and the first electrode terminal; on the other hand, when some of the first tabs have unstable connection or connection failure between them and the first electrode terminal, the remaining first tabs can still achieve electrical connection between the main body and the first electrode terminal, thereby effectively improving the stability and service life of the battery cell.

[0035] In some embodiments, in the first direction, the bending direction of the first sub-taper of one first electrode tab is opposite to the bending direction of the first sub-taper of the other first electrode tab.

[0036] In the above technical solution, by setting the bending direction of the first sub-taper of one first electrode tab in the first direction to be opposite to that of the first sub-taper of another first electrode tab in the first direction, 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 welding parts of the first electrode terminal are opposite. Since the multiple first electrodes tabs and the first electrode terminal are all welded and assembled on the outside of the first electrode terminal away from the main body, 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 electrode terminal can still be satisfied, which is beneficial to improving the overall stability and service life of the battery cell.

[0037] 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.

[0038] In the above technical solution, the electrode assembly has a stacked structure, so that the first electrode piece of the main body is a whole first electrode segment. Thus, by connecting at least one first sub-electrode tab to each first electrode segment, each first electrode piece of the main body can be electrically connected to the first electrode terminal, thereby reducing the risk of failure of some first electrode pieces of the electrode assembly. In addition, in the structure where the flattening and bending directions of at least two first electrode tabs are opposite, it is convenient for the first electrode terminal to be welded to different first electrode tabs, so that at least one sub-electrode tab on each first electrode segment can be welded to the first electrode terminal, which helps to reduce the difficulty of setting a first sub-electrode tab on each first electrode segment.

[0039] In some embodiments, there are multiple first electrode terminals, and each first electrode terminal is welded to at least one first electrode tab and has the solder mark formed thereon.

[0040] In the above technical solution, by setting multiple first electrode terminals on the wall and welding each first electrode terminal to at least one first electrode tab, the multiple first electrode tabs are respectively welded and assembled to the multiple first electrode terminals. This reduces the difficulty of welding and assembling each first electrode tab to the first electrode terminal, and also reduces the manufacturing and assembly difficulty of the first electrode terminals, thereby reducing the manufacturing difficulty of the battery cell. On the other hand, it also reduces the interference between the multiple first electrode tabs.

[0041] In some embodiments, there are two first electrode terminals and two first tabs, each first electrode terminal is welded to one first tab to form the solder mark; in the first direction, the bending direction of the first sub-tab of one first tab is opposite to the bending direction of the first sub-tab of the other first tab.

[0042] In the above technical solution, by setting two first electrode terminals and two first tabs, with each first tab welded to one first electrode terminal, the flow path and flow stability between the main body and the first electrode terminals are improved, while also achieving a one-to-one correspondence and welding assembly structure between the first electrode terminals and the first tabs. This further reduces the difficulty of welding each first tab to the first electrode terminal, as well as the manufacturing and assembly difficulty of the first electrode terminals, thereby reducing the manufacturing difficulty of the battery cell and further reducing the interference between multiple first tabs. Furthermore, by setting the bending directions of the first sub-tabs of the two first tabs to opposite directions, multiple first sub-tabs within the two first tabs can be achieved. The stacking order of the parts where the ear is welded to the first electrode terminal is reversed. Since the multiple first electrode ears and the first electrode terminal are all welded and assembled on the outside of the first electrode terminal away from the main body, even if the first sub-electrode ear near the welding side of the multiple first sub-electrode ears of each first electrode ear is damaged, the damaged first sub-electrode ear in the two first electrode ears with opposite bending directions can be smoothed out. The damaged first sub-electrode ear is connected to a different first electrode segment. Thus, at least one of the multiple first sub-electrode ears connected to the first electrode segment is not damaged, and the electrical connection between the corresponding first electrode segment and the first electrode terminal can still be satisfied, which is beneficial to improving the overall stability and service life of the battery cell.

[0043] In some embodiments, the battery cell further includes a first busbar; the first busbar is located on the side of the wall opposite to the electrode assembly, and the first busbar is electrically connected to a plurality of the first electrode terminals.

[0044] In the above technical solution, by setting a first busbar on the side of the wall away from the electrode assembly, and the first busbar being electrically connected to multiple first electrode terminals, the first busbar can realize the input or output of electrical energy of the battery cell after electrically connecting multiple first electrode terminals into an integral structure. This facilitates the electrical connection of the battery cell with other components in the subsequent assembly process, which helps to reduce the difficulty of inputting or outputting electrical energy of the battery cell and the difficulty of subsequent assembly.

[0045] In some embodiments, the first busbar is connected to the surface of the first electrode terminal on the side of the wall portion facing away from the main body portion in the thickness direction.

[0046] In the above technical solution, by setting the first busbar to be connected to the surface of the first electrode terminal on the side away from the main body in the thickness direction of the wall, the first busbar and the first electrode terminal are arranged in the thickness direction of the wall, thereby reducing the assembly difficulty between the first busbar and the first electrode terminal and reducing the interference between the first busbar and the wall or other components.

[0047] In some embodiments, the first busbar is provided with a plurality of limiting holes, the limiting holes penetrating the first busbar along the thickness direction of the wall portion; along the thickness direction of the wall portion, a groove is provided on the side of the first electrode terminal opposite to the main body portion, the bottom surface of the groove is the first surface, the battery cell further includes a sealing member, the sealing member is connected to the side of the first electrode terminal opposite to the main body portion and seals the groove, at least a portion of the sealing member is inserted into the limiting holes.

[0048] In the above technical solution, by providing a limiting hole that penetrates the first busbar along the thickness direction of the wall on the first busbar, and by configuring at least a portion of the sealing member to be inserted into the limiting hole, the sealing member can play a certain positioning and limiting role for the first busbar, thereby reducing the shaking or displacement of the first busbar during assembly or use with the first electrode terminal. This improves the assembly accuracy between the first busbar and the first electrode terminal and reduces the assembly difficulty between the first busbar and the first electrode terminal. It also improves the assembly stability between the first busbar and the first electrode terminal, thereby enhancing the reliability of the battery cell.

[0049] In some embodiments, along the thickness direction of the wall portion, the sealing member has a second surface facing away from the first electrode tab, and the second surface is the surface of the sealing member furthest from the first electrode tab; the first manifold has a third surface facing away from the wall portion; the limiting hole penetrates the third surface; and the third surface is coplanar with the second surface.

[0050] In the above technical solution, by setting the second surface of the sealing component away from the first tab and the third surface of the first busbar away from the wall as a flat and coplanar structure, it can reduce the phenomenon of bumping or scratching of the sealing component during use, and reduce the interference between the sealing component and other components, so that the first busbar can be electrically connected or assembled with other components during the subsequent assembly of the battery cells, which helps to reduce the difficulty of subsequent assembly of the battery cells.

[0051] In some embodiments, along the thickness direction of the wall portion, a groove is provided on the side of the first electrode terminal away from the main body portion, the bottom surface of the groove is the first surface, and the battery cell further includes a sealing member, the sealing member is connected to the side of the first electrode terminal away from the main body portion and seals the groove; the sealing member is made of metal, and the first busbar is connected to the surface of the sealing member on the side of the wall portion away from the main body portion in the thickness direction.

[0052] In the above technical solution, by connecting the first busbar to the surface of the sealing member on the side away from the main body in the thickness direction of the wall, the first busbar is electrically connected to the first electrode terminal through the sealing member. This reduces the difficulty of the mutual electrical connection between the first busbar and the first electrode terminal and reduces the interference between the first busbar and the wall or other components. On the other hand, it increases the connection area between the first busbar and the sealing member, which is beneficial to improving the assembly stability and reliability of the first busbar.

[0053] Secondly, embodiments of this application also provide a battery device, including the aforementioned battery cell.

[0054] 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

[0055] 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.

[0056] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments; Figure 2 Exploded views of the structure of the battery device provided in some embodiments of this application; Figure 3 This is a schematic diagram of the structure of a battery cell provided in some embodiments of this application; Figure 4 Exploded views of the structure of a single battery cell provided in some embodiments of this application; Figure 5 A partial cross-sectional view of a battery cell perpendicular to the second direction, provided for some embodiments of this application; Figure 6 A partial cross-sectional view of the electrode assembly and first electrode terminal of a battery cell provided in some embodiments of this application after being assembled together; 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 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 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 in other embodiments; Figure 10 A front view of the wall thickness direction of the electrode assembly of a battery cell provided in some embodiments of this application after the first tab and the first electrode terminal are welded and assembled. Figure 11 A cross-sectional view of the first electrode terminal and the sealing member of a battery cell after being assembled together, according to some embodiments of this application; Figure 12 This is a schematic diagram of the structure of a battery cell provided in some embodiments of this application; Figure 13 Exploded views of the battery cell structure provided in some embodiments of this application; Figure 14 A schematic diagram of the electrode assembly of a battery cell provided in some embodiments of this application; Figure 15 A cross-sectional view of the first electrode terminal and the first busbar of a battery cell after being assembled together, as provided in some embodiments of this application; Figure 16 A cross-sectional view of a battery cell after its first electrode terminal and first busbar are assembled together, according to some embodiments of this application; Figure 17 A cross-sectional view of the first electrode terminal and the first busbar of a battery cell provided in other embodiments of this application after being assembled together.

[0057] 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; 221 - First surface; 222 - Groove; 23 - Electrode assembly; 231 - Main body; 231a - Straight area; 231b - Bending area; 2311 - First electrode; 2311a - First electrode segment; 2311b - First bending segment; 2312 - Second electrode; 2312a - Second electrode segment; 2312b - Second bending section; 2313 - Isolator; 232 - First electrode tab; 2321 - Sub-electrode tab; 2321a - Soldering area; 23211 - First sub-electrode tab; 23211a - Connecting end; 23212 - Second sub-electrode tab; 233 - Second electrode tab; 24 - Soldering part; 25 - Second electrode terminal; 26 - Pressure relief component; 27 - Sealing component; 271 - Second surface; 28 - First busbar; 281 - Limiting hole; 282 - Third surface; 29 - Second busbar; 200 - Controller; 300 - Motor; X - Thickness direction of the wall; Y - First direction; Z - Second direction; R - Winding direction. Detailed Implementation

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] In this application, "multiple" means two or more (including two).

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.).

[0071] 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.

[0072] 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.

[0073] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0074] 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.).

[0075] 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.

[0076] 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.

[0077] 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.

[0078] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0079] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] Among them, the gel electrolyte includes a polymer as the electrolyte backbone network, combined with an ionic liquid - lithium salt.

[0087] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0088] 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.

[0089] 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.

[0090] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0091] In some implementations, the electrode assembly has a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0092] In some implementations, the electrode assembly has a stacked structure.

[0093] As an example, multiple positive and negative electrodes can be set, and multiple positive and multiple negative electrodes can be stacked alternately.

[0094] 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.

[0095] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0096] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0097] As an example, the separators can be continuously arranged, either by folding or rolling between any adjacent positive or negative electrode plates.

[0098] In some implementations, the electrode assembly may be flat or polygonal in shape.

[0099] 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.

[0100] 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.

[0101] As an example, a battery cell can be a prismatic battery cell, 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-prismatic batteries, such as hexagonal prismatic batteries.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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, 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 housed within 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 between the main body portion and the first electrode terminal along the thickness direction of the wall portion. The first direction is perpendicular to the thickness direction of the wall portion. The first electrode terminal and the first electrode tab are welded together to form at least one solder mark. Each solder mark passes through at least a portion of the sub-electrode tab along the thickness direction of the wall portion. Two adjacent sub-electrode tabs are fixedly connected only through the solder mark. Each first electrode tab has multiple sub-electrode tabs fixedly connected to the solder mark. In a first direction, the bending directions of the multiple first sub-electrode tabs of the same first electrode tab are the same. Along the thickness direction of the wall portion, the first electrode terminal has a first surface away from the outer surface of the main body portion. At least a portion of the solder mark extends from the first surface into the first electrode tab. The orthographic projection of the solder mark in a projection plane perpendicular to the thickness direction of the wall portion is strip-shaped.

[0114] In this type of battery cell, the first electrode tab includes multiple sub-electrodes stacked together. The sub-electrodes are bent towards a first direction, and portions of the multiple sub-electrodes are stacked along the thickness direction of the wall and then welded to the first electrode terminal to form a solder mark, thereby achieving the assembly connection between the first electrode tab and the first electrode terminal. Each solder mark is a structure that passes through at least a portion of the sub-electrodes along the thickness direction of the wall, and adjacent sub-electrodes are fixedly connected only through the solder mark. This ensures that after the first electrode tab is bent towards the first direction and before it is stacked and welded to the first electrode terminal, the multiple sub-electrodes of the first electrode tab are not fixedly connected or pre-welded, allowing for the smoothing and bending of the multiple sub-electrodes of the first electrode tab before... By welding the first tab and the first electrode terminal together, multiple sub-tabs can move and shift relative to each other during the smoothing and bending process of the first tab. This allows each sub-tab to adapt to the length changes caused by bending, reducing local stress concentration or bulging of the sub-tabs during the smoothing and bending process. This effectively improves the welding quality between the first tab and the first electrode terminal 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 electrode terminal during use, thus improving the stability and reliability of the battery cell. Furthermore, by configuring at least a portion of the weld mark formed by welding the first tab and the first electrode terminal together as extending from the first surface of the first electrode terminal away from the main body into the first tab, the welding assembly between the first tab and the first electrode terminal is configured as a structure in which the first electrode terminal and the first tab are directly welded in the thickness direction of the wall from the side of the first electrode terminal away from the main body. This enables a direct current flow structure between the first tab and the first electrode terminal, which is beneficial to improving the current flow effect between the first electrode terminal and the electrode assembly, thereby reducing the internal resistance of the battery cell. It also helps to optimize the internal layout of the battery cell and improve the internal space utilization of the battery cell, thereby increasing the energy density of the battery cell. On the other hand, since the gap between the first tab and the main body is too small after the first tab is flattened and bent, this assembly structure can reduce the welding difficulty between the first tab and the first electrode terminal and reduce the phenomenon of welding slag and other particles generated by welding the first tab and the first electrode terminal falling into the casing, thereby reducing the risk of internal short circuits in the battery cell during use. In addition, by setting multiple first sub-tabs of the same first electrode tab to a structure in which the bending direction is the same in the first direction, the soldering part can be fixedly connected to multiple first sub-tabs. Furthermore, by setting the orthographic projection of the soldering part in the projection plane perpendicular to the thickness direction of the wall to a strip-shaped structure, the soldering part can be connected to more sub-tabs to improve the overcurrent effect between the first electrode tab and the first electrode terminal.

[0115] 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.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] 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.

[0123] 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.

[0124] 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.

[0125] 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.

[0126] According to some embodiments of this application, refer to Figure 3 Please refer to further details. Figure 4 , Figure 5 , Figure 6 , Figure 7 and Figure 8 , Figure 4 This is an exploded view of the structure of a battery cell 20 provided in some embodiments of this application. Figure 5 This is a partial cross-sectional view of a battery cell 20 provided in some embodiments of this application, perpendicular to the second direction Z. Figure 6 This is a partial cross-sectional view of the electrode assembly 23 and the first electrode terminal 22 of the battery cell 20 after they are assembled together, according to some embodiments of this application. Figure 7 This is a schematic diagram showing the connection of the first electrode segment 2311a and the sub-electrode tab 2321 of the electrode assembly 23 of the battery cell 20 after unfolding, according to some embodiments of this application. Figure 8 This is a cross-sectional view of the main body 231 of the electrode assembly 23 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, and at least one electrode assembly 23. The housing 21 has a wall portion 211. The first electrode terminal 22 is disposed on the wall portion 211. The electrode assembly 23 is housed within the housing 21. The electrode assembly 23 includes a main body 231 and a first electrode tab 232. The main body 231 includes a plurality of first electrode segments 2311a stacked along the first direction Y and having the same polarity. The first electrode tab 232 includes a plurality of sub-electrode tabs 2321 stacked together. Each sub-electrode tab 2321 of each first electrode tab 232 is connected to one end of a first electrode segment 2311a near the wall 211. The sub-electrode tabs 2321 are bent toward the first direction Y, and portions of the plurality of sub-electrode tabs 2321 are stacked between the main body 231 and the first electrode terminal 22 along the thickness direction X of the wall. The first direction Y is perpendicular to the thickness direction X of the wall. The first electrode terminal 22 and the first electrode tab 232 are welded together to form at least one solder mark 24. Each solder mark 24 passes through at least a portion of the sub-electrode tab 2321 along the thickness direction X of the wall portion. Two adjacent sub-electrode tabs 2321 are fixedly connected only through the solder mark 24. Each first electrode tab 232 has a plurality of sub-electrode tabs 23211 fixedly connected to the solder mark 24. In the first direction Y, the bending direction of the plurality of first sub-electrode tabs 23211 of the same first electrode tab 232 is the same. Along the thickness direction X of the wall portion, the outer surface of the first electrode terminal 22 away from the main body portion 231 includes a first surface 221. At least a portion of the solder mark 24 extends from the first surface 221 into the first electrode tab 232. The orthographic projection of the solder mark 24 in the projection plane perpendicular to the thickness direction X of the wall portion is strip-shaped.

[0127] 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.

[0128] 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 23 and prevent, to some extent, electrolyte leakage. When the housing 21 is a non-sealed structure, it can still protect the electrode assembly 23, and a sealing bag may be included between the housing 21 and the electrode assembly 23 to encapsulate the electrode assembly 23 and the electrolyte.

[0129] 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 23 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 23 and the electrolyte.

[0130] 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.

[0131] 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.

[0132] The housing 212 can have 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 23. 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.

[0133] 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 23 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.

[0134] In this embodiment of the application, the electrode assembly 23 includes a main body 231, a first tab 232 and a second tab 233. The main body 231 is the main component of the electrode assembly 23 for chemical reactions to occur inside the battery cell 20. The first tab 232 and the second tab 233 have opposite polarities. The first tab 232 and the second tab 233 are both connected to the main body 231 and are spaced apart.

[0135] The main body 231 of the electrode assembly 23 includes a first electrode 2311, a second electrode 2312, and a separator 2313. The first electrode 2311 and the second electrode 2312 have opposite polarities, i.e., the first electrode 2311 and the second electrode 2312 are the positive electrode and the negative electrode of the electrode assembly 23, respectively. Correspondingly, a first tab 232 is connected to the first electrode 2311, and a second tab 233 is connected to the second electrode 2312. Optionally, the main body 231 of the electrode assembly 23... The structure can be varied. The main body 231 of the electrode assembly 23 can be a wound structure formed by winding the first electrode 2311, the second electrode 2312 and the separator 2313, or a stacked structure formed by alternatingly stacking the first electrode 2311, the second electrode 2312 and the separator 2313. The separator 2313 is disposed between the first electrode 2311 and the second electrode 2312 to insulate and isolate the first electrode 2311 and the second electrode 2312.

[0136] For example, the separator 2313 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.

[0137] Optionally, in Figure 4 and Figure 5 In this embodiment, the first electrode 232 and the second electrode 233 are both connected to the same end of the main body 231 in the thickness direction X of the wall. Of course, in other embodiments, the first electrode 232 and the second electrode 233 may also be structures that are respectively connected to the two ends of the main body 231 in the thickness direction X of the wall.

[0138] For example, the first tab 232 is connected to the end of the first electrode 2311 facing the wall 211 in the thickness direction X of the wall portion, and the second tab 233 is connected to the end of the second electrode 2312 facing the wall 211 in the thickness direction X of the wall portion.

[0139] The first electrode tab 232 of the electrode assembly 23 is a multilayer metal foil structure connected to one end of the first electrode 2311 in the thickness direction X of the wall portion. That is, the first electrode tab 232 includes a plurality of sub-electrodes 2321 stacked together, and each layer of metal foil is a sub-electrodes 2321. Similarly, the second electrode tab 233 of the electrode assembly 23 is a multilayer metal foil structure connected to one end of the second electrode 2312 in the thickness direction X of the wall portion. It should be noted that the first tab 232 and the first electrode 2311 can be separate structures. For example, the first tab 232 and the first current collector of the first electrode 2311 can be welded together. Of course, the first tab 232 and the first electrode 2311 can also be integrally formed. For example, the first current collector of the first tab 232 and the first electrode 2311 can be formed by integrally cutting the same metal foil to form the first tab 232 and the first current collector. Similarly, the second tab 233 and the second electrode 2312 can be separate structures. For example, the second tab 233 and the second current collector of the second electrode 2312 can be welded together. Of course, the second tab 233 and the second electrode 2312 can also be integrally formed. For example, the second current collector of the second tab 233 and the second electrode 2312 can be formed by integrally cutting the same metal foil to form the second tab 233 and the second current collector.

[0140] The first electrode tab 232 includes a plurality of sub-electrodes 2321 stacked together. Each sub-electrode 2321 of each first electrode tab 232 is connected to the end of a first electrode segment 2311a near the wall portion 211. That is, the first electrode tab 232 is disposed at the end of the main body portion 231 facing the wall portion 211 in the thickness direction X of the wall portion. The sub-electrodes 2321 in the first electrode tab 232 are connected to the end of the corresponding first electrode segment 2311a near the wall portion 211 in the thickness direction X of the wall portion. And one sub-electrode 2321 in each first electrode tab 232 is connected to one first electrode segment 2311a, so that the positions where the plurality of sub-electrodes 2321 of each first electrode tab 232 are connected to the main body portion 231 are arranged at intervals along the first direction Y. It should be noted that in embodiments where there are multiple first electrode tabs 232, each of the multiple first electrode tabs 232 is disposed at one end of the main body portion 231 facing the wall portion 211 in the thickness direction X of the wall portion, and the multiple first electrode tabs 232 are arranged at intervals along the second direction Z. Correspondingly, it can be a structure in which the first electrode segment 2311a is connected to only one sub-electrode tab 2321 of one first electrode tab 232, or it can be a structure in which the first electrode segment 2311a is connected to one sub-electrode tab 2321 of a portion of the first electrode tabs 232, or it can be a structure in which the first electrode segment 2311a is connected to one sub-electrode tab 2321 of each first electrode tab 232.

[0141] Sub-electrode tabs 2321 are bent toward the first direction Y, and portions of multiple sub-electrode tabs 2321 are stacked along the thickness direction X of the wall between the main body 231 and the first electrode terminal 22. That is, the sub-electrode tabs 2321 have a structure in which the extension direction from one end connected to the first electrode segment 2311a to away from the first electrode segment 2311a changes from extending along the thickness direction X of the wall to extending along the first direction Y. The portions of multiple sub-electrode tabs 2321 extending along the first direction Y are stacked and at least partially located between the main body 231 and the first electrode terminal 22, such that at least a portion of the first electrode tab 232 is located between the main body 231 and the first electrode terminal 22 in the thickness direction X of the wall, so that the first electrode terminal 22, at least a portion of the first electrode tab 232, and the main body 231 are arranged sequentially along the thickness direction X of the wall. It should be noted that the sub-electrode 2321 can be a structure that bends to one side only in the first direction Y, so that the sub-electrode 2321 includes only one bending position. Of course, the sub-electrode 2321 can also be a structure that bends to one side in the first direction Y first and then bends to the other side in the first direction Y, so that the sub-electrode 2321 is a continuously bent structure and includes two bending positions.

[0142] In this embodiment, the main body 231 of the electrode assembly 23 has a flat region 231a, that is, the flat region 231a is the flat portion of the main body 231 of the electrode assembly 23. For example, in... Figure 8 In this structure, electrode assembly 23 has a wound structure, and the central axis of the winding of electrode assembly 23 extends along the thickness direction X of the wall portion. Correspondingly, the main body portion 231 also has two bending regions 231b, and the two bending regions 231b are respectively connected to the two opposite ends of the straight region 231a 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 23 has a stacked structure, refer to... Figure 9 As shown, Figure 9 In some embodiments of this application, the main body 231 of the electrode assembly 23 of the battery cell 20 is shown in a cross-sectional view perpendicular to the thickness direction X of the wall in other embodiments. In this view, the main body 231 of the electrode assembly 23 is entirely a flat region 231a, that is, the main body 231 of the electrode assembly 23 only includes the flat region 231a.

[0143] The first electrode 2311 includes a first electrode segment 2311a located in the flat region 231a, and the second electrode 2312 includes a second electrode segment 2312a located in the flat region 231a. Correspondingly, the flat region 231a of the electrode assembly 23 includes multiple first electrode segments 2311a and multiple second electrode segments 2312a, and the first electrode segments 2311a and second electrode segments 2312a are stacked and alternately arranged along the first direction Y. It should be noted that if the electrode assembly 23 is a wound structure, see [reference needed]. Figure 8 As shown, the first pole segment 2311a is the straight portion of the first pole 2311 located in the straight region 231a, and the second pole segment 2312a is the straight portion of the second pole 2312 located in the straight region 231a. Correspondingly, the first electrode 2311 includes a plurality of first electrode segments 2311a located in the flat region 231a, and the second electrode 2312 includes a plurality of second electrode segments 2312a located in the flat region 231a. The first electrode 2311 also includes a plurality of first bent segments 2311b located in the bent region 231b, and the second electrode 2312 also includes a plurality of second bent segments 2312b located in the bent region 231b. In the winding direction R of the electrode assembly 23, the first bent segments 2311b connect two adjacent first electrode segments 2311a, and the first bent segments 2311b and the first electrode segments 2311a are alternately arranged. Similarly, in the winding direction R of the electrode assembly 23, the second bent segments 2312b connect two adjacent second electrode segments 2312a, and the second bent segments 2312b and the second electrode segments 2312a are alternately arranged.

[0144] It should be noted that if the electrode assembly 23 is a stacked structure, the electrode assembly 23 includes a plurality of first electrode plates 2311 and a plurality of second electrode plates 2312. The first electrode plates 2311 and the second electrode plates 2312 are alternately stacked along the first direction Y. Correspondingly, the first electrode segment 2311a is the first electrode plate 2311 and the second electrode segment 2312a is the second electrode plate 2312.

[0145] It should be noted that if the electrode assembly 23 is a wound structure, each of the multiple first electrode segments 2311a in the main body 231 may be connected to a sub-electrode tab 2321, or only some of the first electrode segments 2311a may be connected to a sub-electrode tab 2321; if the electrode assembly 23 is a stacked structure, each of the first electrode segments 2311a may be connected to a sub-electrode tab 2321.

[0146] The battery cell 20 includes at least one electrode assembly 23, meaning that the number of electrode assemblies 23 housed within the housing 21 can be one or more. For example, in... Figure 4 In this structure, the electrode assembly 23 has a wound structure. Correspondingly, there can be one or more electrode assemblies 23 housed in the outer casing 21. After the first electrode plate 2311 and the second electrode plate 2312 of the main body portion 231 of each electrode assembly 23 are wound and formed, the tail end of the separator 2313 of the main body portion 231 of each electrode assembly 23 will continue to be wound and correspondingly cover the outside of the first electrode plate 2311 and the second electrode plate 2312 to form the main body portion 231 of a single electrode assembly 23. See [link to relevant documentation]. Figure 4 As shown, only one electrode assembly 23 is disposed within the casing 21 of the battery cell 20. Of course, in other embodiments, the electrode assembly 23 disposed within the casing 21 can be two, three, four, five, six, seven, eight or more, and multiple electrode assemblies 23 are stacked along the first direction Y. It should be noted that if the electrode assembly 23 has a stacked structure, the number of electrode assemblies 23 disposed within the casing 21 is usually one.

[0147] In this embodiment, the first electrode terminal 22 is connected to the first tab 232 of the electrode assembly 23 to serve 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.

[0148] 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.

[0149] The first electrode terminal 22 and the first electrode tab 232 are welded together to form at least one solder mark 24. That is, a portion of the first electrode tab 232 and the first electrode terminal 22 are stacked on each other in the thickness direction X of the wall, and this portion of the first electrode tab 232 and the first electrode terminal 22 are connected through the solder mark 24. In other words, the first electrode terminal 22 and the first electrode tab 232 are directly welded together to form the solder mark 24, so that no current collector or other components for connecting the first electrode terminal 22 and the first electrode tab 232 are provided inside the battery cell 20. Correspondingly, the solder mark 24 is a region where the portion of the first electrode tab 232 and the first electrode terminal 22 are welded together to form a region that is fused together or a region where a solder mark is formed.

[0150] Each solder mark 24 passes through at least a portion of the sub-electrode tabs 2321 along the thickness direction X of the wall portion. That is, the portion of the solder mark 24 located within the first electrode terminal 22 and the portion of the solder mark 24 located within the first electrode tab 232 are arranged and connected along the thickness direction X of the wall portion. Each solder mark 24 is fixedly connected to at least a portion of the sub-electrode tabs 2321. Correspondingly, the solder mark 24 can be a structure in which some sub-electrode tabs 2321 are sequentially connected and stacked in the thickness direction X of the wall portion, or it can be a structure in which all sub-electrode tabs 2321 are sequentially connected and stacked in the thickness direction X of the wall portion.

[0151] The two adjacent sub-tabs 2321 are fixedly connected only by the solder mark 24. That is, the two adjacent sub-tabs 2321 are stacked and fixedly connected only by the solder mark 24, without any other fixing structure. Before the solder mark 24 is formed by welding the first electrode terminal 22 and the first electrode 232, the two adjacent sub-tabs 2321 are unfixed to each other and can move and separate relative to each other.

[0152] For example, in the embodiments of this application, the solder mark 24 is a solder mark structure formed by laser welding of the first electrode terminal 22 and the first electrode tab 232.

[0153] In this embodiment, the first sub-taper 23211 is the sub-taper 2321 that is welded to the first electrode terminal 22 among a plurality of sub-tapers 2321, that is, the first sub-taper 23211 is the sub-taper 2321 that is fixedly connected to the soldering portion 24 among a plurality of sub-tapers 2321. Correspondingly, the first sub-taper 23211 is the sub-taper 2321 that is passed through by the soldering portion 24 and has a soldering area 2321a formed thereon (see...). Figure 6 and Figure 7 (As shown).

[0154] See Figure 6As shown, the bending directions of the multiple first sub-taps 23211 of the same first electrode tab 232 are the same. It should be noted that the bending direction of the first sub-taps 23211 is the extension direction of the part of the first sub-taps 23211 that is fixedly connected to the solder mark 24 on the extension trajectory from the end of the first sub-taps 23211 connected to the first electrode segment 2311a to the extension trajectory away from the first electrode segment 2311a. The bending direction of the first sub-taps 23211 is unidirectional in the first direction Y. Correspondingly, in the same first electrode tab 232, the sub-taps 2321 that are soldered to the first electrode terminal 22 and have solder mark 24 are bent toward the same side in the first direction Y. That is to say, the sub-taps 2321 that have solder mark area 2321a in the same first electrode tab 232 are bent toward the same side in the first direction Y.

[0155] Along the thickness direction X of the wall portion, the outer surface of the first electrode terminal 22 away from the main body portion 231 includes a first surface 221. That is, the first surface 221 is a part of the outer surface of the first electrode terminal 22 away from the main body portion 231, such that the first surface 221 is also a part of the outer surface of the first electrode terminal 22 facing the outer side of the outer shell 21.

[0156] At least a portion of the solder mark 24 extends from the first surface 221 into the first tab 232. That is, in the thickness direction X of the wall portion, the solder mark 24 has a structure in which at least a portion extends from the first surface 221 of the outer surface of the first electrode terminal 22 towards the main body 231 and into the first tab 232. This is such that the solder mark 24, in the thickness direction X of the wall portion, is connected to the first surface 221 away from the outer surface of the main body 231, and that in a projection plane perpendicular to the thickness direction X of the wall portion, the solder mark... The orthographic projection of the portion 24 connected to the first tab 232 can be a structure located within the orthographic projection of the portion 24 connected to the first electrode terminal 22. That is, when welding and assembling the first electrode terminal 22 and the first tab 232, the welding equipment is a structure that welds and assembles the first electrode terminal 22 and the first tab 232 from the outside of the housing 21 in the thickness direction X of the wall portion, so that the welding portion 24 is a structure that first passes through the area where the first surface 221 of the first electrode terminal 22 is located and then extends into the first tab 232.

[0157] As an example, the first electrode terminal 22 has a groove 222 on the side of its wall facing away from the main body 231 in the thickness direction X. The entire groove wall of the groove 222 is a part of the outer surface of the first electrode terminal 22 facing away from the main body 231, and the bottom surface of the groove 222 is the first surface 221. Correspondingly, at least a portion of the soldering portion 24 extends from the bottom surface of the groove 222 through the bottom wall of the groove 222 and then into the first electrode tab 232. Of course, in other embodiments, the first electrode terminal 22 may also be a structure without the groove 222. Correspondingly, the surface of the first electrode terminal 22 facing away from the main body 231 is the first surface 221, and the soldering portion 24 extends through the entire first electrode terminal 22.

[0158] Optionally, the outer surface of the solder stamp 24 facing away from the main body 231 in the thickness direction X of the wall portion can be a structure that is flush with the first surface 221, or a structure in which part of the solder stamp 24 protrudes from the first surface 221.

[0159] For example, the material of the first electrode terminal 22 can be various, such as copper, iron, aluminum, steel or aluminum alloy.

[0160] In this embodiment, the orthographic projection of the solder mark 24 in the projection plane perpendicular to the thickness direction X of the wall is strip-shaped. That is, in the projection plane perpendicular to the thickness direction X of the wall, the orthographic projection of the solder mark 24 is a long strip-shaped structure extending along a straight line trajectory or an arc trajectory.

[0161] In some embodiments, the battery cell 20 may further include a second electrode terminal 25, which is electrically connected to the second tab 233 of the electrode assembly 23, so that the second electrode terminal 25 and the first electrode terminal 22 can cooperate to input or output electrical energy of the battery cell 20.

[0162] For example, see Figure 4 and Figure 5 As shown, the second electrode terminal 25 is also disposed on the wall portion 211, and the second electrode terminal 25 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 25 passes through the second electrode lead-out hole of the wall portion 211 and is insulatedly mounted on the wall portion 211. That is to say, no electrical connection is formed between the second electrode terminal 25 and the wall portion 211 of the outer casing 21.

[0163] For example, the material of the second electrode terminal 25 can also be various, such as copper, iron, aluminum, steel or aluminum alloy.

[0164] It should be noted that the second electrode 233 can have the same structure as the first electrode 232. Similarly, the assembly structure between the second electrode terminal 25 and the second electrode 233 can be the same as the assembly structure between the first electrode terminal 22 and the first electrode 232.

[0165] In some embodiments, see Figure 3 and Figure 4 As shown, the battery cell 20 may also include a pressure relief component 26, 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.

[0166] For example, the pressure relief component 26 is disposed on the end cap 213 of the housing 21. Of course, in other embodiments, the pressure relief component 26 may also be disposed on the housing 212 of the housing 21. Similarly, the pressure relief component 26 and the housing 21 may be integrally formed or separately disposed. If the pressure relief component 26 and the housing 21 are separately disposed, the pressure relief component 26 may be connected to the housing 21 by welding or other means. Correspondingly, the pressure relief component 26 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 26 and the housing 21 are integrally formed, the pressure relief component 26 is a region on the housing 21 with a weak structure, such as a region on the housing 21 with a groove.

[0167] In this embodiment, the first electrode tab 232 includes a plurality of sub-electrode tabs 2321 stacked together. The sub-electrode tabs 2321 are bent toward the first direction Y, and portions of the plurality of sub-electrode tabs 2321 are stacked along the thickness direction X of the wall and then welded to the first electrode terminal 22 to form a solder mark 24, thereby realizing the assembly connection between the first electrode tab 232 and the first electrode terminal 22. Each solder mark 24 has a structure that passes through at least a portion of the sub-electrode tab 2321 along the thickness direction X of the wall, and two adjacent sub-electrode tabs 2321 are fixedly connected only through the solder mark 24. This means that after the first electrode tab 232 is bent toward the first direction Y and before the first electrode tab 232 is stacked and welded to the first electrode terminal 22, the plurality of sub-electrode tabs 2321 of the first electrode tab 232 are not fixedly connected or pre-welded, so as to facilitate the assembly connection of the plurality of sub-electrode tabs 2321 of the first electrode tab 232. After the first tab 232 and the first electrode terminal 22 are smoothed and bent, they are then welded together. This allows multiple sub-tabs 2321 to move and shift relative to each other during the smoothing and bending process. This enables each sub-tab 2321 to adapt to the length changes caused by the bending, reducing local stress concentration or bulging during the smoothing and bending process. This effectively improves the welding quality between the first tab 232 and the first electrode terminal 22 and mitigates cracking or breakage of the sub-tabs 2321 during assembly or use. This reduces the risk of unstable connection and connection failure between the first tab 232 and the first electrode terminal 22 during use, thus improving the stability and reliability of the battery cell 20. Furthermore, by configuring at least a portion of the solder mark 24 formed by welding the first electrode tab 232 and the first electrode terminal 22 to extend from the first surface 221 of the first electrode terminal 22 away from the main body 231 into the first electrode tab 232, the welding assembly between the first electrode tab 232 and the first electrode terminal 22 is a structure in which the first electrode terminal 22 and the first electrode terminal 232 are directly welded in the thickness direction X of the wall from the side of the first electrode terminal 22 away from the main body 231. This enables a direct current flow structure between the first electrode tab 232 and the first electrode terminal 22, which is beneficial for improving the first electrode terminal 22 and the electrode assembly. The current flow between components 23 is reduced to decrease the internal resistance of the battery cell 20. This also helps to optimize the internal layout of the battery cell 20 and improve the internal space utilization of the battery cell 20, thereby increasing the energy density of the battery cell 20. On the other hand, since the gap between the first tab 232 and the main body 231 is too small after the first tab 232 is flattened and bent, this assembly structure can reduce the welding difficulty between the first tab 232 and the first electrode terminal 22, and can reduce the phenomenon of welding slag and other particles generated by welding the first tab 232 and the first electrode terminal 22 falling into the outer casing 21, thereby reducing the risk of internal short circuit in the battery cell 20 during use.In addition, by setting multiple first sub-tabs 23211 of the same first tab 232 to have the same bending direction in the first direction Y, the soldering part 24 can be fixedly connected to multiple first sub-tabs 23211. Furthermore, by setting the orthographic projection of the soldering part 24 in the projection plane perpendicular to the thickness direction X of the wall to a strip-shaped structure, the soldering part 24 can be interconnected with more sub-tabs 2321, thereby improving the overcurrent effect between the first tab 232 and the first electrode terminal 22.

[0168] According to some embodiments of this application, refer to Figure 6 and Figure 7 Please refer to further details. Figure 10 As shown, Figure 10 This is a front view of the electrode assembly 23 of the battery cell 20 provided in some embodiments of this application after the first tab 232 and the first electrode terminal 22 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 solder mark 24 is a strip structure extending along a straight trajectory, and the length direction of the orthographic projection of the solder mark 24 is parallel to the first direction Y, or the angle between the length direction of the orthographic projection of the solder mark 24 and the first direction Y is less than or equal to 30°. In other words, the orthographic projection of the solder mark 24 in the projection plane perpendicular to the thickness direction X of the wall is a long strip structure extending along the first direction Y or in a direction approximately equal to the first direction Y. The length direction of the orthographic projection of the solder mark 24 in the projection plane perpendicular to the thickness direction X of the wall is parallel or approximately parallel to the stacking direction of the plurality of first pole segments 2311a and the arrangement direction of the connection positions of the plurality of sub-pole tabs 2321 and the main body 231. Correspondingly, the length direction of the solder mark area 2321a formed on the sub-pole tab 2321 is also parallel to the first direction Y or the angle between the length direction of the orthographic projection of the solder mark 24 and the first direction Y is less than or equal to 30°.

[0169] For example, in the projection plane perpendicular to the thickness direction X of the wall portion, if the length direction of the orthographic projection of the solder mark 24 is parallel to the first direction Y, then the angle between the length direction of the orthographic projection of the solder mark 24 and the first direction Y is 0°. If the angle between the length direction of the orthographic projection of the solder mark 24 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 solder mark 24 and the first direction Y can be 0.1°, 0.2°, 0.3°, or 0°. The value of any one of the following: 4°, 0.5°, 1°, 1.5°, 2°, 2.5°, 3°, 3.5°, 4°, 4.5°, 5°, 6°, 7°, 8°, 9°, 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24°, 25°, 26°, 27°, 28°, 29°, 30°, or a range between any two.

[0170] Optionally, the solder mark 24 formed by welding each first tab 232 to the first electrode terminal 22 can be one or more.

[0171] In this embodiment, since the multiple first electrode segments 2311a are stacked along the first direction Y, and the sub-electrode tabs 2321 are bent towards the first direction Y, the connection positions of the multiple sub-electrode tabs 2321 of the first electrode tab 232 and the corresponding first electrode segments 2311a are arranged along the first direction Y. This ensures that the multiple sub-electrode tabs 2321 of the first electrode tab 232 are arranged along the first direction Y before being smoothed and bent. Therefore, after the multiple sub-electrode tabs 2321 are bent towards the first direction Y, the soldering portion 24 is positioned at a thickness perpendicular to the wall portion. The orthographic projection in the projection plane of direction X is set as a strip structure extending along a straight trajectory, and the length direction of the orthographic projection of the solder part 24 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 solder part 24 and the first direction Y is less than or equal to 30°, thereby enabling the solder part 24 to be connected to more sub-tabs 2321, thereby further improving the overcurrent effect between the first tab 232 and the first electrode terminal 22, and further improving the connection stability between the first tab 232 and the first electrode terminal 22.

[0172] In some embodiments, see Figure 10 As shown, there are multiple solder marks 24 on the first tab 232, and these solder marks 24 are arranged at intervals along the second direction Z. The thickness direction X of the wall, the first direction Y, and the second direction Z 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 solder marks 24 are arranged at intervals along their width direction.

[0173] In this embodiment, by providing multiple solder marks 24 on the first tab 232, and arranging the multiple solder marks 24 at intervals along the second direction Z, the orthographic projection of the multiple solder marks 24 in the projection plane perpendicular to the thickness direction X of the wall portion is a structure arranged at intervals along its width direction. This structure of the battery cell 20 can further improve the welding reliability and welding area between the first tab 232 and the first electrode terminal 22, thereby further improving the current flow effect between the first tab 232 and the first electrode terminal 22, and further improving the performance of the first tab. The connection stability between the sub-tab 232 and the first electrode terminal 22 is improved. On the other hand, even if there is a poor connection between the sub-tab 2321 and some of the solder marks 24, the sub-tab 2321 can still maintain the connection with the first electrode terminal 22 through the remaining solder marks 24. This improves the fault tolerance rate of the welding assembly between the sub-tab 2321 and the first electrode terminal 22, and improves the electrical connection stability between the sub-tab 2321 and the first electrode terminal 22, thereby reducing the risk of connection failure between the sub-tab 2321 and the first electrode terminal 22.

[0174] In some embodiments, combined with Figure 6 and Figure 10 As shown, each first sub-pole tab 23211 is fixedly connected to at least two solder pads 24.

[0175] Each first sub-electrode tab 23211 is fixedly connected to at least two solder pads 24. That is, the sub-electrode tab 2321 that is soldered to the first electrode terminal 22 is penetrated by at least two solder pads 24, resulting in at least two solder pad areas 2321a (e.g., first sub-electrode tabs 2321) being formed on the sub-electrode tab 2321 that is soldered to the first electrode terminal 22. Figure 7 (As shown).

[0176] In this embodiment, by fixing each first sub-tab 23211 to at least two solder marks 24, each first sub-tab 23211 that is soldered to the first electrode terminal 22 is passed through by at least two solder marks 24. On the one hand, this can increase the current flow area and current flow path between the first sub-tab 23211 and the first electrode terminal 22. On the other hand, it can still be electrically connected to the first electrode terminal 22 through other solder marks 24 even if the connection between the first sub-tab 23211 and one or more solder marks 24 fails, which is beneficial to improving the electrical connection stability between the first sub-tab 23211 and the first electrode terminal 22.

[0177] In some embodiments, see Figure 10As shown, in the projection plane perpendicular to the thickness direction X of the wall portion, the width of the orthographic projection of the solder mark 24 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.

[0178] Among them, Figure 10 In the process, the width of the orthographic projection of the solder mark 24 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.

[0179] For example, the width W of the orthographic projection of the solder mark 24 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.

[0180] In this embodiment, on the one hand, the width of the orthographic projection of the solder mark 24 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 solder mark 24 and the first sub-tab 23211, thereby improving the overcurrent effect between the first tab 232 and the first electrode terminal 22, and also improving the connection stability between the first tab 232 and the first electrode terminal 22. On the other hand, the width of the orthographic projection of the solder mark 24 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 solder mark 24 formed by the welding of the first electrode terminal 22 and the first tab 232 is too large, which helps to reduce the power required for welding and assembling the first electrode terminal 22 and the first tab 232, and can reduce the area of ​​the first sub-tab 23211 that is passed through by the solder mark 24, thereby reducing the risk of damage to the first sub-tab 23211.

[0181] According to some embodiments of this application, in conjunction with Figure 6 and Figure 7 As shown, the area through which the first sub-taper 23211 is pierced by the soldering part 24 forms a soldering area 2321a. The surface area of ​​the first sub-taper 23211 on one side in its thickness direction is S1, and the sum of the areas of all soldering areas 2321a on the same first sub-taper 23211 is S2, satisfying 0.0075≤S2 / S1≤0.1.

[0182] Wherein, S1 is the area of ​​one side of the surface of a single first sub-taper 23211 in its thickness direction after unfolding. The solder area 2321a is the area through which the first sub-taper 23211 is passed by the corresponding solder part 24, and is also the area where the first sub-taper 23211 is connected to the corresponding solder part 24. It is also the area where the first sub-taper 23211 and the first electrode terminal 22 are welded together to form the solder part 24. Correspondingly, if only one solder area 2321a is formed on the first sub-taper 23211, then S2 is the area of ​​the solder area 2321a. If multiple solder areas 2321a are formed on the first sub-taper 23211, then S2 is the sum of the areas of the multiple solder areas 2321a.

[0183] If the first sub-taper 23211 is unfolded and the thickness direction of the first sub-taper 23211 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 first sub-taper 23211 in the projection plane perpendicular to the first direction Y, and S2 is the sum of the areas of the orthographic projections of all solder parts 24 located on the first sub-taper 23211 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 solder parts 24 located on the first sub-taper 23211 to the area of ​​the orthographic projection of the corresponding first sub-taper 23211 in the projection plane perpendicular to the first direction Y.

[0184] 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.

[0185] In this embodiment, on the one hand, the sum of the areas of all solder areas 2321a is set to be greater than or equal to 0.0075 times the surface area of ​​the corresponding first sub-tab 23211 on one side in its thickness direction, so as to increase the welding area between a single first sub-tab 23211 and the first electrode terminal 22, thereby improving the overcurrent effect between the single first sub-tab 23211 and the first electrode terminal 22, and also improving the connection stability between the single first sub-tab 23211 and the first electrode terminal 22. On the other hand, the sum of the areas of all solder areas 2321a is set to be less than or equal to 0.1 times the surface area of ​​the corresponding first sub-tab 23211 on one side in its thickness direction, so as to alleviate the phenomenon that the area through which the first sub-tab 23211 is traversed by the solder part 24 is too large, thereby reducing the welding difficulty between the single first sub-tab 23211 and the first electrode terminal 22, and also reducing the power required for welding and assembling the first electrode terminal 22 and the first tab 232.

[0186] According to some embodiments of this application, in conjunction with Figure 6 and Figure 7 As shown, the extension dimension of the sub-pole tab 2321 from one end connected to the first pole segment 2311a to the end away from the first pole segment 2311a is 5mm-40mm.

[0187] The extension dimension of the sub-electrode 2321 from one end connected to the first pole segment 2311a to the end away from the first pole segment 2311a is the length dimension of the sub-electrode 2321 along its extension trajectory from one end connected to the first pole segment 2311a to the end away from the first pole segment 2311a.

[0188] It should be noted that if the sub-tab 2321 is unfolded and the thickness direction of the sub-tab 2321 is set to be parallel to the first direction Y (e.g.) Figure 7 As shown), the extension dimension of the sub-electrode 2321 from one end connected to the first pole segment 2311a to the end away from the first pole segment 2311a is the length dimension of the sub-electrode 2321 in the thickness direction X of the wall portion, that is, the extension dimension of the sub-electrode 2321 from one end connected to the first pole segment 2311a to the end away from the first pole segment 2311a is L, which satisfies 5mm≤L≤40mm.

[0189] For example, the extension dimension of the sub-pole tab 2321 from one end connected to the first pole segment 2311a to the end away from the first pole segment 2311a 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.

[0190] It should be noted that the first electrode tab 232 and the first electrode terminal 22 are directly welded together, and the portions of the multiple sub-electrode tabs 2321 connected to the solder mark portion 24 are stacked between the first electrode terminal 22 and the main body portion 231. Therefore, the extension dimension of the sub-electrode tab 2321 from one end connected to the first electrode segment 2311a to the end away from the first electrode segment 2311a can be made smaller to save space. In some embodiments, the extension dimension of the sub-electrode tab 2321 from one end connected to the first electrode segment 2311a to the end away from the first electrode segment 2311a can be 15mm-20mm.

[0191] In this embodiment, on the one hand, the extension dimension of the sub-tab 2321 from one end connected to the first electrode segment 2311a to the end away from the first electrode segment 2311a is set to be greater than or equal to 5mm, so as to reduce the difficulty of bending multiple sub-tabs 2321 towards the first direction Y, and to reduce the difficulty of stacking and welding multiple sub-tabs 2321 with the first electrode terminal 22 after bending. It also helps to increase the area where the sub-tabs 2321 can be stacked and welded with the first electrode terminal 22 after bending. On the other hand, before the multiple sub-tabs 2321 of the first electrode 232 are welded and assembled with the first electrode terminal 22, The fact that they are not fixed to each other allows multiple sub-tabs 2321 to move and shift relative to each other during the process of smoothing and bending the first tab 232. By setting the extension dimension of the sub-tab 2321 from one end connected to the first electrode segment 2311a to the end away from the first electrode segment 2311a to less than or equal to 40mm, the phenomenon of redundancy or local bulging of the sub-tab 2321 after bending can be effectively alleviated. This is to optimize the space occupied by the first tab 232 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.

[0192] According to some embodiments of this application, see Figure 6As shown, the first sub-taper 23211 has a connection end 23211a connected to the first pole segment 2311a. In the projection plane perpendicular to the thickness direction X of the wall portion, at least a portion of the orthographic projection of the connection end 23211a of the first sub-taper 23211 is located within the orthographic projection of the solder mark portion 24.

[0193] 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 23211a of the first sub-taper 23211 lies within the orthographic projection of the solder portion 24. That is, at least a portion of the multiple first sub-tapers 23211 are structures that extend from between the main body portions 231 of the solder portion 24, bend towards the first direction Y, and are at least partially located between the solder portion 24 and the main body portion 231. It should be noted that the first sub-taper 23211, after bending, can be a structure extending beyond one side of the solder portion 24 in the first direction Y, or it can be a structure that does not extend beyond both sides of the solder portion 24 in the first direction Y.

[0194] Optionally, only some of the first sub-tabs 23211 may have their connecting ends 23211a located between the solder pad 24 and the main body 231, or all of the first sub-tabs 23211 may have their connecting ends 23211a located between the solder pad 24 and the main body 231. For example, in... Figure 6 In the middle, the connection end 23211a of a portion of the first sub-taper 23211 is located between the soldering part 24 and the main body part 231, and the orthographic projection of the connection end 23211a of another portion of the first sub-taper 23211 in the projection plane perpendicular to the thickness direction X of the wall portion does not overlap with the orthographic projection of the soldering part 24 in the projection plane perpendicular to the thickness direction X of the wall portion.

[0195] In this embodiment, by setting the orthographic projection of at least a portion of the first sub-tab 23211a in the projection plane perpendicular to the thickness direction X of the wall portion to a structure located within the orthographic projection of the soldering portion 24 in the projection plane perpendicular to the thickness direction X of the wall portion, the portion of the first sub-tab 23211 has a structure in which more or even the entire portion is located between the soldering portion 24 and the main body portion 231. The battery cell 20 with this structure can, on the one hand, improve the separation effect of the first tab 232 between the first electrode terminal 22 and the main body portion 231, thereby reducing the risk of the first electrode terminal 22 and the first tab 232 burning or damaging the main body portion 231 during the welding assembly process. On the other hand, it can realize the connection of more portions of the soldering portion 24 and the first sub-tab 23211, which is beneficial to improve the connection stability and current flow area between the first sub-tab 23211 and the first electrode terminal 22.

[0196] According to some embodiments of this application, please continue to refer to Figure 6 As shown, within the same first electrode tab 232, multiple sub-electrodes 2321 arranged sequentially from the first to the nth along the bending direction of the first sub-electrode tab 23211 are all first sub-electrodes 23211, where n is greater than or equal to 2. That is, the first to the nth sub-electrodes 2321 arranged sequentially along the bending direction of the first sub-electrode tab 2321 within the same first electrode tab 232 are all welded to the first electrode terminal 22.

[0197] In this embodiment, by setting multiple sub-tabs 2321 arranged sequentially from the first to the nth in the bending direction of the first sub-tab 2321 in the same first tab 232 as first sub-tabs 23211, the multiple sub-tabs 2321 arranged sequentially from the first in the bending direction of the first sub-tab 23211 are all welded to the first electrode terminal 22. This structure can improve the welding range between the first electrode terminal 22 and the first tab 232, and can realize the fixed connection between the solder stamp 24 and more sub-tabs 2321, thereby improving the connection stability and overcurrent effect between the first electrode terminal 22 and the first tab 232.

[0198] According to some embodiments of this application, please continue to refer to Figure 6 As shown, the plurality of sub-tabs 2321 also include at least one second sub-tab 23212 that is not fixedly connected to the soldering portion 24. All the second sub-tabs 23212 are located on one side of the plurality of first sub-tabs 23211 in the bending direction of the first sub-tabs 23211, and at least one second sub-tab 23212 is partially bent and located on one side of the first electrode terminal 22 in the first direction Y.

[0199] The second sub-electrode 23212 is the sub-electrode 2321 among the multiple sub-electrode 2321 that is not welded to the first electrode terminal 22 and is located on one side of the multiple first sub-electrode 23211 in the bending direction of the first sub-electrode 23211. That is, the second sub-electrode 23212 is not penetrated by the soldering part 24 and has a soldering area 2321a. Correspondingly, the second sub-electrode 23212 among the multiple sub-electrode 2321 that is not fixedly connected to the soldering part 24 is a structure that is arranged with the multiple first sub-electrode 23211 in the first direction Y.

[0200] At least one second sub-taper 23212 is partially bent and located on one side of the first electrode terminal 22 in the first direction Y. That is, at least one second sub-taper 23212 is a structure that extends along the thickness direction X of the wall to one side of the first electrode terminal 22 in the first direction Y, or at least one second sub-taper 23212 is partially bent in the opposite direction to the bending direction of the first sub-taper 23211 and located on one side of the first electrode terminal 22 in the first direction Y.

[0201] As an example, in Figure 6 In the first electrode terminal 22, the second sub-electrode 23212 is bent in the opposite direction to the bending direction of the first sub-electrode 23211 and is located on one side of the first electrode terminal 22 in the first direction Y.

[0202] In this embodiment, by setting at least one second sub-taper 23212, which is not connected to the soldering portion 24 and is located on one side of the plurality of first sub-tapers 23211 in the bending direction of the first sub-taper 23211, to a structure that bends and extends to one side of the first electrode terminal 22 in the first direction Y, the overall regularity of the first electrode 232 is improved, which helps to alleviate the phenomenon of the second sub-taper 23212 occupying redundant space or being inserted upside down into the main body portion 231.

[0203] In some embodiments, see Figure 6 As shown, in the projection plane perpendicular to the thickness direction X of the wall portion, the orthographic projections of all the second sub-taperes 23212 are located within the orthographic projection of the main body portion 231. That is, in the first direction Y, the second sub-taperes 23212 do not extend beyond the sides of the main body portion 231.

[0204] In this embodiment, by setting the orthographic projection of all the second sub-tabs 23212 in the projection plane perpendicular to the thickness direction X of the wall portion to a structure located within the orthographic projection of the main body portion 231 in the projection plane perpendicular to the thickness direction X of the wall portion, the phenomenon of the second sub-tabs 23212 protruding from the side of the main body portion 231 in the first direction Y can be alleviated, thereby optimizing the space occupied by the electrode assembly 23 in the first direction Y and reducing the interference between the first tab 232 and other components.

[0205] 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, all the sub-tabs 2321 in the first tab 232 are fixedly connected to the soldering portion 24. That is, all the sub-tabs 2321 in the first tab 232 are first sub-tabs 23211, that is, all the sub-tabs 2321 in the first tab 232 are soldered to the first electrode terminal 22. Correspondingly, each sub-tab 2321 in the first tab 232 is penetrated by the soldering portion 24 and a soldering area 2321a is formed.

[0206] It should be noted that, to fix all the sub-tabs 2321 in the first electrode tab 232 to the soldering part 24, the size of the first electrode terminal 22 can be increased. This would allow sub-tabs 2321 to be connected to multiple first electrode segments 2311a in the main body 231, and each sub-tab 2321 in the first electrode tab 232 can be soldered to the first electrode terminal 22 after being smoothed and bent. Alternatively, the size of the first electrode terminal 22 can remain unchanged, and only the portion of the first electrode segment 2311a located on the side of the first electrode segment 2311a connected to the first sub-tab 23211 in the bending direction of the first sub-tab 23211 can be left unconnected to the sub-tab 2321. That is, some of the first electrode segments 2311a are not provided with sub-tabs 2321. For example, in Figure 6 In this embodiment, all the second sub-electrode tabs 23212 can be removed. However, in order to ensure that each first electrode segment 2311a still has the function of electrochemical reaction, the electrode assembly 23 is a wound structure.

[0207] In this embodiment, by fixing all the sub-tabs 2321 in the first tab 232 to the soldering part 24, each sub-tab 2321 in the first tab 232 is welded to the first electrode terminal 22, thereby further improving the overcurrent effect and connection stability between the first tab 232 and the first electrode terminal 22, and reducing the risk of the overcurrent path of the first electrode segment 2311a being too long or the connection failing due to the sub-tabs 2321 on some first electrode segments 2311a not being welded to the first electrode terminal 22.

[0208] According to some embodiments of this application, refer to Figure 5 and Figure 6 Please refer to further details. Figure 11 As shown, Figure 11This is a cross-sectional view of the battery cell 20 provided in some embodiments of this application after the first electrode terminal 22 and the sealing member 27 are assembled together. Along the thickness direction X of the wall portion, a groove 222 is provided on the side of the first electrode terminal 22 away from the main body portion 231. The groove wall surface of the groove 222 is a part of the outer surface of the first electrode terminal 22 away from the main body portion 231, and the bottom surface of the groove 222 is the first surface 221.

[0209] The groove 222 is a structure that is recessed in the thickness direction X of the wall portion from the side of the first electrode terminal 22 away from the main body portion 231 towards the main body portion 231. Correspondingly, the groove wall surface of the groove 222 is connected to the end face of the first electrode terminal 22 in the thickness direction X of the wall portion that is furthest from the main body portion 231. Both the groove wall surface of the groove 222 and the end face of the first electrode terminal 22 in the thickness direction X of the wall portion that is furthest from the main body portion 231 are part of the outer surface of the first electrode terminal 22 that is furthest from the main body portion 231.

[0210] The bottom surface of the groove 222 is the first surface 221, that is, at least part of the soldering part 24 is a structure that extends from the bottom surface of the groove 222 toward the main body 231 through the first electrode terminal 22 and into the first electrode tab 232.

[0211] In this embodiment, by providing a groove 222 on the side of the first electrode terminal 22 away from the main body 231, and the bottom surface of the groove 222 being the first surface 221, the bottom wall of the groove 222 in the first electrode terminal 22 is welded to the first tab 232 to form a weld mark 24. The battery cell 20 with this structure can reduce the thickness of the area of ​​the first electrode terminal 22 used for welding with the first tab 232, thereby reducing the power required for welding and assembling the first electrode terminal 22 and the first tab 232, which is beneficial to reducing the welding difficulty between the first electrode terminal 22 and the first tab 232. On the other hand, it is not necessary to set the first electrode terminal 22 as an overall thinning structure, which is beneficial to reduce the assembly difficulty between the first electrode terminal 22 and the wall 211 while satisfying the structural strength of the first electrode terminal 22.

[0212] In some embodiments, please continue to see Figure 5 , Figure 6 and Figure 11 As shown, the battery cell 20 may also include a sealing member 27, which is connected to the side of the first electrode terminal 22 away from the main body 231, and the sealing member 27 seals the groove 222.

[0213] The sealing member 27 is connected to the side of the first electrode terminal 22 facing away from the main body 231. Specifically, the sealing member 27 is a structure connected to the outer surface of the side of the first electrode terminal 22 facing away from the main body 231, so that the sealing member 27 can seal the groove 222, and the first surface 221 is located on the side of the sealing member 27 facing the main body 231 in the thickness direction X of the wall portion. Correspondingly, the sealing member 27 can be a structure connected to the side surface of the groove 222, or it can be a structure connected to the end face of the first electrode terminal 22 furthest from the main body 231 in the thickness direction X of the wall portion.

[0214] As an example, see Figure 11 As shown, the sealing member 27 is connected to the side of the groove 222. Part of the sealing member 27 is located inside the groove 222, and the sealing member 27 extends beyond the end face of the first electrode terminal 22 in the thickness direction X of the wall portion, which is furthest from the main body portion 231 in the thickness direction X of the wall portion. Of course, in other embodiments, the sealing member 27 may also be a structure in which the entire sealing member 27 is located inside the groove 222, that is, the sealing member 27 does not extend beyond the end face of the first electrode terminal 22 in the thickness direction X of the wall portion, which is furthest from the main body portion 231 in the thickness direction X of the wall portion.

[0215] Optionally, if the sealing element 27 is made of metal, it can be connected to the first electrode terminal 22 by welding, bonding or snap-fitting. If the sealing element 27 is made of non-metallic material, it can be connected to the first electrode terminal 22 by bonding or snap-fitting.

[0216] In this embodiment, by connecting a sealing member 27 to the first electrode terminal 22, and the sealing member 27 having a sealing groove 222 structure, the phenomenon of impurities or liquids entering the groove 222 can be reduced during the use of the battery cell 20. Thus, the sealing member 27 can also provide a certain degree of protection for the soldering part 24, thereby reducing the risk of the soldering part 24 being worn or corroded and rusted during use.

[0217] According to some embodiments of this application, refer to Figure 12 , Figure 13 and Figure 14 As shown, Figure 12 This is a schematic diagram of the structure of a battery cell 20 provided in some embodiments of this application. Figure 13 This is an exploded view of the structure of a battery cell 20 provided in some embodiments of this application. Figure 14This is a schematic diagram of the structure of the electrode assembly 23 of the battery cell 20 provided in some embodiments of this application. The electrode assembly 23 may include a plurality of first tabs 232 with the same polarity. The plurality of first tabs 232 are all connected to one end of the main body portion 231 facing the wall portion 211. The plurality of first tabs 232 are spaced apart along the second direction Z, and the plurality of first tabs 232 are welded to the first electrode terminal 22 and form a solder mark portion 24. The thickness direction X of the wall portion, the first direction Y, and the second direction Z are perpendicular to each other.

[0218] In this configuration, multiple first tabs 232 are welded to the first electrode terminal 22 to form a solder mark 24. This configuration can be either a structure in which multiple first tabs 232 are welded to the same first electrode terminal 22, or a structure in which each first tab 232 is welded to one first electrode terminal 22. In other words, the battery cell 20 is provided with multiple first electrode terminals 22, and the first electrode terminals 22 and the first tabs 232 correspond one-to-one and are welded together.

[0219] For example, in Figure 13 and Figure 14 In this embodiment, there are two first electrode tabs 232 connected to the main body 231. Of course, in other embodiments, the number of first electrode tabs 232 connected to the main body 231 can also be three, four, five or more.

[0220] In this embodiment, by providing a plurality of first tabs 232 arranged at intervals along the second direction Z and having the same polarity at one end of the main body 231 facing the wall 211, and by welding the plurality of first tabs 232 to the first electrode terminal 22 to form a solder mark 24, 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 231 and the first electrode terminal 22, thereby improving the current flow effect between the main body 231 and the first electrode terminal 22. On the other hand, when some of the first tabs 232 have unstable connection or connection failure with the first electrode terminal 22, the remaining first tabs 232 can still achieve electrical connection between the main body 231 and the first electrode terminal 22, thereby effectively improving the stability and service life of the battery cell 20.

[0221] According to some embodiments of this application, in conjunction with Figure 6 and Figure 14 As shown, each first electrode tab 232 has multiple sub-electrodes 2321, each of which is fixedly connected to the solder pad 24. In the first direction Y, the bending direction of the first sub-electrodes 23211 of one first electrode tab 232 is opposite to the bending direction of the first sub-electrodes 23211 of another first electrode tab 232.

[0222] In the first direction Y, the bending direction of the first sub-taper 23211 of one first electrode 232 is opposite to the bending direction of the first sub-taper 23211 of the other first electrode 232. That is, in the first direction Y, the first sub-taper 23211 of one first electrode 232 bends toward one side of the main body 231, while the first sub-taper 23211 of the other first electrode 232 bends toward the other side of the main body 231, so that the first sub-taper 23211 of one first electrode 232 and the first sub-taper 23211 of the other first electrode 232 are structures that bend in opposite directions in the first direction Y. Correspondingly, at least two of the multiple first electrodes 232 have flattening bending directions that are opposite.

[0223] It should be noted that among the multiple sub-taps 2321 of the same first electrode tab 232, at least one sub-taps 2321 located on one side of the multiple first sub-taps 23211 in the bending direction of the first sub-taps 23211 has a structure that is not connected to the solder mark portion 24. In this structure, if the same first electrode tab 232 is connected to multiple first electrode segments 2311a, then the multiple sub-taps 2321 of the same first electrode tab 232 includes a second sub-taps 23212, that is, at least one of the multiple sub-taps 2321 of the same first electrode tab 2322. If the tab 2321 is not connected to the soldering part 24, then if multiple sub-tabs 2321 of the same first tab 232 are all connected to the soldering part 24, then the portion of the multiple first electrode segments 2311a located on one side of the first sub-tab 23211 in the bending direction of the first sub-tab 23211 is not connected to the sub-tab 2321. That is to say, in both cases, at least one first electrode segment 2311a is not fixedly connected to the soldering part 24 through the sub-tab 2321. Therefore, if the electrode assembly 23 is a wound structure, The first electrode segment 2311a, which is not fixedly connected to the soldering part 24 via the sub-electrode tab 2321, can be guided by the first bending segment 2311b and other first electrode segments 2311a. Correspondingly, the first electrode tab 232 connected to the main body 231 can be one or more, and can be a structure in which the smoothing and bending directions of multiple first electrode tabs 232 are all the same, or a structure in which the smoothing and bending directions of at least two first electrode tabs 232 are opposite. If the electrode assembly 23 is a stacked structure, the first electrode segment 2311a, which is not fixedly connected to the soldering part 24 via the sub-electrode tab 2321, can be guided by the first bending segment 2311b and other first electrode segments 2311a. The first electrode segment 2311a cannot conduct current, and there is a phenomenon of partial failure of the first electrode segment 2311a. Therefore, there are multiple first electrode ears 232 connected to the main body 231, and at least two first electrode ears 232 have opposite flattening and bending directions. That is, in the first direction Y, the bending direction of the first sub-electrode ear 23211 of one first electrode ear 232 is opposite to the bending direction of the first sub-electrode ear 23211 of another first electrode ear 232. Correspondingly, each first electrode segment 2311a is connected to at least one first sub-electrode ear 23211.

[0224] In this embodiment, by setting the bending direction of the first sub-taper 23211 of one first electrode tab 232 in the first direction Y to be opposite to that of the first sub-taper 23211 of the other first electrode tab 232 in the first direction Y, the smoothing bending directions of at least two first electrodes tabs 232 are opposite. Using this structure, the battery cell 20 can achieve a reversed stacking order of the portions where multiple first sub-tapers 23211 of at least two first electrodes tabs 232 are welded to the first electrode terminal 22. Since the multiple first electrodes tabs 232 and the first electrode terminal 22 are all welded and assembled on the outside of the first electrode terminal 22 away from the main body 231, Therefore, even if the portion of the first sub-taper 23211 near the welding side among the multiple first sub-taper 23211 of each first tab 232 is damaged, the damaged first sub-taper 23211 in the two first tabs 232 with opposite bending directions can be smoothed out. The damaged first sub-taper 23211 is connected to different first electrode segments 2311a. This ensures that at least one of the multiple first sub-taper 23211 connected to the first electrode segment 2311a is not damaged, and thus the electrical connection between the corresponding first electrode segment 2311a and the first electrode terminal 22 can still be satisfied, which is beneficial to improving the overall stability and service life of the battery cell 20.

[0225] According to some embodiments of this application, in conjunction with Figure 7 and Figure 9 As shown, in an embodiment where the electrode assembly 23 has a stacked structure, the main body 231 includes a plurality of first electrode plates 2311 and a plurality of second electrode plates 2312. The first electrode plates 2311 and the second electrode plates 2312 have opposite polarities, and the first electrode plates 2311 and the second electrode plates 2312 are alternately stacked along the first direction Y. Correspondingly, the first electrode plate 2311 is a first electrode segment 2311a, and each first electrode segment 2311a has a first sub-electrode tab 23211 connected to one end of the wall portion near the wall portion 211 in the thickness direction X of the wall portion. That is, each first electrode segment 2311a in the stacked electrode assembly 23 has at least one sub-electrode tab 2321 connected to one end of the wall portion near the wall portion 211 in the thickness direction X of the wall portion, and at least one sub-electrode tab 2321 on each first electrode segment 2311a is fixedly connected to the soldering portion 24.

[0226] In this embodiment, the electrode assembly 23 has a stacked structure, so that the first electrode piece 2311 of the main body 231 is a whole first electrode segment 2311a. Thus, by connecting at least one first sub-electrode tab 23211 to each first electrode segment 2311a, each first electrode piece 2311 of the main body 231 can be electrically connected to the first electrode terminal 22, thereby reducing the risk of failure of some first electrode pieces 2311 of the electrode assembly 23. In the structure where the flattening and bending directions of at least two first electrode tabs 232 are opposite, it is convenient for the first electrode terminal 22 to be welded to different first electrode tabs 232, so that at least one sub-electrode tab 2321 on each first electrode segment 2311a can be welded to the first electrode terminal 22, which helps to reduce the difficulty of providing a first sub-electrode tab 23211 on each first electrode segment 2311a.

[0227] In some embodiments, see Figure 12 and Figure 13 As shown, there are multiple first electrode terminals 22, and each first electrode terminal 22 is welded to at least one first electrode tab 232 and has a solder mark 24.

[0228] The plurality of first electrode terminals 22 are also arranged at intervals along the second direction Z. Each first electrode terminal 22 is welded to at least one first electrode tab 232 and forms a solder mark 24. That is, it can be a structure in which each first electrode terminal 22 is welded to one first electrode tab 232, or a structure in which each first electrode terminal 22 is welded to a plurality of first electrode tabs 232, or a structure in which a portion of the first electrode terminals 22 are welded to one first electrode tab 232 and another portion of the first electrode terminals 22 are welded to a plurality of first electrode tabs 232.

[0229] As an example, in the embodiments of this application, the first electrode terminal 22 and the first electrode tab 232 are in a one-to-one correspondence structure, and each first electrode terminal 22 and a corresponding first electrode tab 232 are arranged and welded together in the thickness direction X of the wall to form at least one solder mark 24.

[0230] Of course, in other embodiments, the battery cell 20 may also have only one first electrode terminal 22, and all the first tabs 232 are welded and assembled to the same first electrode terminal 22 to form a structure of multiple solder marks 24, and the multiple first tabs 232 are respectively welded and connected to different positions of the first electrode terminal 22 to form solder marks 24.

[0231] In this embodiment, by providing a plurality of first electrode terminals 22 on the wall portion 211, and welding each first electrode terminal 22 to at least one first tab 232, the plurality of first tabs 232 are respectively welded and assembled to the plurality of first electrode terminals 22. This reduces the difficulty of welding and assembling each first tab 232 to the first electrode terminal 22, and also reduces the manufacturing and assembly difficulty of the first electrode terminals 22, thereby reducing the manufacturing difficulty of the battery cell 20. On the other hand, it also reduces the interference between the plurality of first tabs 232.

[0232] In some embodiments, see Figure 12 , Figure 13 and Figure 14 As shown, there are two first electrode terminals 22 and two first electrode tabs 232. Each first electrode terminal 22 is welded to one first electrode tab 232 to form a solder mark 24. In the first direction Y, the bending direction of the first sub-electrode tab 23211 of one first electrode tab 232 is opposite to the bending direction of the first sub-electrode tab 23211 of the other first electrode tab 232. That is, the two first electrode terminals 22 are welded to the two first electrode tabs 232 respectively, and the first sub-electrode tab 23211 of the two first electrode tabs 232 is bent towards different sides of the main body 231 in the first direction Y.

[0233] In this embodiment, by setting two first electrode terminals 22 and two first tabs 232, with each first tab 232 welded to one first electrode terminal 22, the flow path and flow stability between the main body 231 and the first electrode terminal 22 are improved, while also achieving a one-to-one correspondence and welding assembly structure between the first electrode terminals 22 and the first tabs 232. This further reduces the difficulty of welding each first tab 232 to the first electrode terminal 22, as well as the manufacturing and assembly difficulty of the first electrode terminal 22, thereby reducing the manufacturing difficulty of the battery cell 20 and further reducing the interference between multiple first tabs 232. Simultaneously, the bending directions of the first sub-tabs 23211 of the two first tabs 232 are set to opposite directions, so that multiple first sub-tabs 23211 of the two first tabs 232 are connected to the first electrode terminal 22. The stacking order of the welded parts is reversed. Since the multiple first tabs 232 and the first electrode terminals 22 are all welded and assembled on the outside of the first electrode terminals 22 away from the main body 231, even if the first sub-tabs 23211 near the welding side of the multiple first sub-tabs 23211 of each first tab 232 are damaged, the damaged first sub-tabs 23211 in the two first tabs 232 with opposite bending directions can be smoothed out. The damaged first sub-tabs 23211 are connected to different first electrode segments 2311a. Thus, at least one first sub-tab 23211 among the multiple first sub-tabs 23211 connected to the first electrode segment 2311a is not damaged, and the electrical connection between the corresponding first electrode segment 2311a and the first electrode terminal 22 can still be satisfied, which is beneficial to improving the overall stability and service life of the battery cell 20.

[0234] According to some embodiments of this application, refer to Figure 12 and Figure 13 Please refer to further details. Figure 15 As shown, Figure 15 This is a cross-sectional view of the battery cell 20 after the first electrode terminal 22 and the first busbar 28 are assembled together, according to some embodiments of this application. The battery cell 20 may also include the first busbar 28, which is located on the side of the wall portion 211 opposite to the electrode assembly 23, and the first busbar 28 is electrically connected to a plurality of first electrode terminals 22.

[0235] The first busbar 28 is located on the outside of the housing 21 and serves to electrically connect multiple first electrode terminals 22. Optionally, the electrical connection structure between the first busbar 28 and the multiple first electrode terminals 22 can be various. The first busbar 28 can be a structure that is directly connected to the first electrode terminals 22, such as by welding or snap-fit. Of course, in an embodiment where a sealing member 27 is also connected to the first electrode terminal 22 and the sealing member 27 is made of metal, the first busbar 28 can also be a structure that is electrically connected to the first electrode terminal 22 through the sealing member 27. Correspondingly, the material of the sealing member 27 can be various, such as copper, iron, aluminum, steel or aluminum alloy.

[0236] In this embodiment, by providing a first busbar 28 on the side of the wall portion 211 away from the electrode assembly 23, and by electrically connecting the first busbar 28 to a plurality of first electrode terminals 22, the first busbar 28 can realize the input or output of electrical energy to the battery cell 20 after electrically connecting the plurality of first electrode terminals 22 into an integral structure. This facilitates the electrical connection of the battery cell 20 with other components during the subsequent assembly process, which helps to reduce the difficulty of inputting or outputting electrical energy to the battery cell 20 and the difficulty of subsequent assembly.

[0237] According to some embodiments of this application, see Figure 15 As shown, the first busbar 28 is connected to the surface of the first electrode terminal 22 on the side of the wall portion facing away from the main body portion 231 in the thickness direction X. That is, the first busbar 28 is a structure located on the side of the first electrode terminal 22 facing away from the main body portion 231 in the thickness direction X of the wall portion and is directly connected to the first electrode terminal 22 to electrically connect the first busbar 28 and the first electrode terminal 22.

[0238] As an example, the first busbar 28 is welded to the first electrode terminal 22. Of course, in other embodiments, the first busbar 28 and the first electrode terminal 22 may also be connected to each other by a snap-fit ​​structure.

[0239] In this embodiment, by configuring the first busbar 28 to be connected to the surface of the first electrode terminal 22 on the side of the wall portion away from the main body portion 231 in the thickness direction X, the first busbar 28 and the first electrode terminal 22 are arranged in the thickness direction X of the wall portion, thereby reducing the assembly difficulty between the first busbar 28 and the first electrode terminal 22, and reducing the interference between the first busbar 28 and the wall portion 211 or other components.

[0240] In some embodiments, see Figure 12 , Figure 13 and Figure 15As shown, the first busbar 28 is provided with a plurality of limiting holes 281, which penetrate the first busbar 28 along the thickness direction X of the wall portion. Along the thickness direction X of the wall portion, the first electrode terminal 22 is provided with a groove 222 on the side opposite to the main body portion 231, and the bottom surface of the groove 222 is the first surface 221. The battery cell 20 also includes a sealing member 27, which is connected to the side of the first electrode terminal 22 opposite to the main body portion 231 and seals the groove 222. At least a portion of the sealing member 27 is inserted into the limiting hole 281.

[0241] In this embodiment, the limiting holes 281 on the first busbar 28 correspond one-to-one with the first electrode terminals 22. Each first electrode terminal 22 is connected to a sealing member 27 inserted into a limiting hole 281. Correspondingly, the sealing member 27 may be partially located within the groove 222, and the sealing member 27 may extend beyond the end face of the first electrode terminal 22 in the thickness direction X of the wall portion, at the end furthest from the main body portion 231 in the thickness direction X of the wall portion. Alternatively, in other embodiments, the sealing member 27 may be connected to the end face of the first electrode terminal 22 in the thickness direction X of the wall portion, at the end furthest from the main body portion 231.

[0242] For example, in the embodiments of this application, there are two first tabs 232, corresponding to two first electrode terminals 22, and two limiting holes 281 are provided on the first busbar 28.

[0243] It should be noted that in embodiments where the first busbar 28 is connected to the surface of the first electrode terminal 22 on the side opposite to the main body 231 in the thickness direction X of the wall portion, the first busbar 28 may not have a limiting hole 281. (Refer to...) Figure 16 As shown, Figure 16 This is a cross-sectional view of the battery cell 20 after the first electrode terminal 22 and the first busbar 28 are assembled together according to some embodiments of this application. The sealing member 27 is located on the side of the first busbar 28 facing the first electrode terminal 22 in the thickness direction X of the wall. Correspondingly, the sealing member 27 is a structure in which the entire structure is located in the groove 222, that is, the sealing member 27 does not extend beyond the end face of the first electrode terminal 22 in the thickness direction X of the wall that is furthest from the main body 231.

[0244] It should be noted that in embodiments where there are multiple second electrode terminals 25, see [reference needed]. Figure 12 and Figure 13 As shown, a second busbar 29 can also be provided to electrically connect multiple second electrode terminals 25. The structure of the second busbar 29 can be the same as that of the first busbar 28, and the connection structure between the second busbar 29 and the second electrode terminals 25 can also be the same as the connection structure between the first busbar 28 and the first electrode terminal 22.

[0245] In this embodiment, by providing a limiting hole 281 that penetrates the first busbar 28 along the thickness direction X of the wall portion, and by configuring at least a portion of the sealing member 27 to be inserted into the limiting hole 281, the sealing member 27 can play a certain positioning and limiting role for the first busbar 28, thereby reducing the shaking or displacement of the first busbar 28 during assembly or use with the first electrode terminal 22. This improves the assembly accuracy between the first busbar 28 and the first electrode terminal 22 and reduces the assembly difficulty between them. It also improves the assembly stability between the first busbar 28 and the first electrode terminal 22, thereby enhancing the reliability of the battery cell 20.

[0246] In some embodiments, see Figure 15 As shown, along the thickness direction X of the wall portion, the sealing member 27 has a second surface 271 that is away from the first electrode tab 232, and the second surface 271 is the surface of the sealing member 27 that is furthest from the first electrode tab 232. The first busbar 28 has a third surface 282 that is away from the wall portion 211. The limiting hole 281 penetrates the third surface 282, and the third surface 282 is coplanar with the second surface 271.

[0247] In this embodiment, by setting the second surface 271 of the sealing member 27 away from the first tab 232 and the third surface 282 of the first busbar 28 away from the wall portion 211 as flush and coplanar, the sealing member 27 can be reduced from bumping or scratching during use, and the interference between the sealing member 27 and other components can be reduced. This facilitates the electrical connection or assembly of the first busbar 28 with other components during the subsequent assembly of the battery cell 20, which helps to reduce the difficulty of subsequent assembly of the battery cell 20.

[0248] According to some embodiments of this application, refer to Figure 17 As shown, Figure 17 This is a cross-sectional view of the battery cell 20 after the first electrode terminal 22 and the first busbar 28 are assembled together, according to some embodiments of this application. Along the thickness direction X of the wall portion, a groove 222 is provided on the side of the first electrode terminal 22 facing away from the main body 231. The bottom surface of the groove 222 is a first surface 221. The battery cell 20 also includes a sealing member 27, which is connected to the side of the first electrode terminal 22 facing away from the main body 231 and seals the groove 222. The sealing member 27 is made of metal, and the first busbar 28 is connected to the surface of the sealing member 27 on the side of the wall portion facing away from the main body 231 along the thickness direction X.

[0249] The first busbar 28 is connected to the surface of the sealing member 27 on the side away from the main body 231 in the thickness direction X of the wall portion. That is, the second surface 271 of the sealing member 27 away from the first electrode tab 232 is connected to the first busbar 28. In other words, the first busbar 28 is a structure located on the side of the sealing member 27 away from the main body 231 in the thickness direction X of the wall portion and connected to the sealing member 27. This makes the first busbar 28 an indirect connection between the sealing member 27 and the first electrode terminal 22, so as to electrically connect the first busbar 28 and the first electrode terminal 22. Correspondingly, the sealing member 27 is made of metal.

[0250] As an example, the first busbar 28 is welded to the sealing member 27. Of course, in other embodiments, the first busbar 28 and the sealing member 27 may also be interlocked or have other structures.

[0251] It should be noted that in this embodiment, the sealing member 27 may be partially located within the groove 222, and the sealing member 27 may extend beyond the end face of the first electrode terminal 22 in the thickness direction X of the wall portion, which is furthest from the main body portion 231 in the thickness direction X of the wall portion. Of course, in other embodiments, the sealing member 27 may also be entirely located within the groove 222, and the second surface 271 of the sealing member 27 facing away from the first electrode tab 232 may be flush with and coplanar with the end face of the first electrode terminal 22 in the thickness direction X of the wall portion, which is furthest from the main body portion 231 in the thickness direction X of the wall portion.

[0252] In this embodiment, by connecting the first busbar 28 to the surface of the sealing member 27 on the side away from the main body 231 in the thickness direction X of the wall portion, the first busbar 28 is electrically connected to the first electrode terminal 22 through the sealing member 27. This reduces the difficulty of the mutual electrical connection between the first busbar 28 and the first electrode terminal 22, and reduces the interference between the first busbar 28 and the wall portion 211 or other components. On the other hand, it increases the connection area between the first busbar 28 and the sealing member 27, which is beneficial to improving the assembly stability and reliability of the first busbar 28.

[0253] 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.

[0254] 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.

[0255] 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.

[0256] 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.

[0257] 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.

[0258] Optionally, the battery cell 20 disposed within the housing 10 can be one or more. For example, in... Figure 2 In 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.

[0259] 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.

[0260] 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.

[0261] 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.

[0262] The electrical device can be any of the aforementioned devices or systems that utilize battery cells 20.

[0263] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0264] 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; as well as At least one electrode assembly is housed within the housing. The electrode assembly includes a main body and a first electrode tab. The main body includes a plurality of first electrode segments stacked along a 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 between the main body and the first electrode terminal. The first direction is perpendicular to the thickness direction of the wall. The first electrode terminal and the first electrode tab are welded together to form at least one solder mark. Each solder mark passes through at least a portion of the sub-electrode tab along the thickness direction of the wall portion. Two adjacent sub-electrode tabs are fixedly connected only through the solder mark. Each first electrode tab has a plurality of sub-electrode tabs fixedly connected to the solder mark. In the first direction, the bending direction of the plurality of first sub-electrode tabs of the same first electrode tab is the same. Along the thickness direction of the wall portion, the outer surface of the first electrode terminal away from the main body portion includes a first surface. At least a portion of the solder mark extends from the first surface into the first electrode tab, and the orthographic projection of the solder mark in a projection plane perpendicular to the thickness direction of the wall portion is strip-shaped.

2. 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 solder mark is a strip structure extending along a straight trajectory, and the length direction of the orthographic projection of the solder mark is parallel to the first direction or the angle between the length direction of the orthographic projection of the solder mark and the first direction is less than or equal to 30°.

3. The battery cell according to claim 2, characterized in that, The first electrode tab has multiple solder marks, which are spaced apart along the second direction. The thickness direction of the wall portion is perpendicular to the first direction and the second direction.

4. The battery cell according to claim 3, characterized in that, Each of the first sub-tabs is fixedly connected to at least two of the solder pads.

5. The battery cell according to claim 2, characterized in that, In the projection plane perpendicular to the thickness direction of the wall portion, the width of the orthographic projection of the 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.

6. The battery cell according to claim 1, characterized in that, The area through which the first sub-electrode is pierced by the solder mark forms a solder mark area. The surface area of ​​the first 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 first sub-electrode is S2, satisfying 0.0075≤S2 / S1≤0.

1.

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

8. The battery cell according to claim 1, characterized in that, The first sub-taper has a connection 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 connection end of the first sub-taper is located within the orthographic projection of the solder mark portion.

9. The battery cell according to claim 1, 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.

10. The battery cell according to claim 1, characterized in that, The plurality of said sub-tabs also include at least one second sub-tab that is not fixedly connected to the soldered portion, all of the second sub-tabs being located on one side of the plurality of first sub-tabs in the bending direction of the first sub-tabs, and at least one second sub-tab being partially bent and located on one side of the first electrode terminal in the first direction.

11. The battery cell according to claim 10, characterized in that, In the projection plane perpendicular to the thickness direction of the wall portion, the orthographic projections of all the second sub-taperes lie within the orthographic projection of the main body portion.

12. The battery cell according to claim 1, characterized in that, All of the sub-tabs in the first electrode tab are fixedly connected to the solder mark portion.

13. The battery cell according to claim 1, characterized in that, Along the thickness direction of the wall portion, a groove is provided on the side of the first electrode terminal away from the main body portion, the groove wall surface is a part of the outer surface of the first electrode terminal away from the main body portion, and the groove bottom surface is the first surface.

14. The battery cell according to claim 13, characterized in that, The battery cell also includes: A sealing element is connected to the side of the first electrode terminal away from the main body, and the sealing element seals the groove.

15. The battery cell according to any one of claims 1-14, 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 portion. The plurality of first electrode tabs are spaced apart along the second direction, and the plurality of first electrode tabs are welded to the first electrode terminal to form the solder mark portion. The thickness direction of the wall portion, the first direction and the second direction are perpendicular to each other.

16. The battery cell according to claim 15, characterized in that, 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.

17. The battery cell according to claim 16, 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.

18. The battery cell according to claim 15, characterized in that, There are multiple first electrode terminals, and each first electrode terminal is welded to at least one first electrode tab and forms the solder mark portion.

19. The battery cell according to claim 18, characterized in that, There are two first electrode terminals and two first electrode tabs. Each first electrode terminal is welded to one first electrode tab to form the solder mark 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.

20. The battery cell according to claim 18, characterized in that, The battery cell also includes: A first busbar is located on the side of the wall opposite to the electrode assembly, and the first busbar is connected to a plurality of the first electrode terminals.

21. The battery cell according to claim 20, characterized in that, The first busbar is connected to the surface of the first electrode terminal on the side of the wall portion facing away from the main body portion in the thickness direction.

22. The battery cell according to claim 21, characterized in that, The first manifold is provided with a plurality of limiting holes, which penetrate the first manifold along the thickness direction of the wall portion; Along the thickness direction of the wall portion, a groove is provided on the side of the first electrode terminal away from the main body portion, the bottom surface of the groove is the first surface, the battery cell also includes a sealing member, the sealing member is connected to the side of the first electrode terminal away from the main body portion and seals the groove, at least a portion of the sealing member is inserted into the limiting hole.

23. The battery cell according to claim 22, characterized in that, Along the thickness direction of the wall portion, the sealing member has a second surface opposite to the first electrode tab, and the second surface is the surface of the sealing member furthest from the first electrode tab. The first manifold has a third surface opposite to the wall portion, the limiting hole penetrates the third surface, and the third surface is coplanar with the second surface.

24. The battery cell according to claim 20, characterized in that, Along the thickness direction of the wall portion, a groove is provided on the side of the first electrode terminal away from the main body portion, the bottom surface of the groove is the first surface, and the battery cell also includes a sealing member, which is connected to the side of the first electrode terminal away from the main body portion and seals the groove. The sealing member is made of metal, and the first busbar is connected to the surface of the sealing member on the side of the wall portion away from the main body portion in the thickness direction.

25. A battery device, characterized in that, Includes the battery cell as described in any one of claims 1-24.

26. An electrical appliance, characterized in that, Includes a battery cell as described in any one of claims 1-24, the battery cell being used to provide electrical energy.

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