Battery monomer, battery device and electric device

Abstract

The invention 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 lead-out piece and an electrode assembly, the first electrode lead-out piece is arranged on the shell. The electrode assembly is arranged in the shell and comprises a main body part and a first tab; the first tab comprises a root area and a welding and printing area which are connected, the root area is connected with the main body part, the welding and printing area comprises a first area and a second area, the first area is connected with the root area through the second area, and a plurality of welding and printing grooves are formed in the welding and printing area; the sum of the areas of all the welding printing grooves in the unit area of the first area is larger than the sum of the areas of all the welding printing grooves in the unit area of the second area, the welding printing area and the first electrode leading-out piece are welded to form a first welding printing part, and the first area is connected with and surrounds the outer side of the first welding printing part. Therefore, the phenomenon of local stress concentration at the edge of the first area or the first welding printing part is reduced, and the risk of cracking or fracture of the first tab in the use process is reduced.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery cell, a battery device, and an electrical device. Background Art

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

[0003] In battery technology, a battery device includes a case and a battery cell accommodated in the case. The battery cell includes an outer shell and an electrode assembly accommodated in the outer shell. Correspondingly, an electrode terminal is also provided on the outer shell. The electrode terminal is electrically connected to the tab of the electrode assembly to realize the input or output of electrical energy of the battery cell through the electrode terminal. However, the tab of the existing battery cell is prone to cracking or even breaking during use, resulting in the risk of unstable connection or connection failure between the electrode terminal and the electrode assembly during use, which is not conducive to improving the stability and service life of the battery cell. Summary of the Invention

[0004] The embodiments of the present application provide a battery cell, a battery device, and an electrical device, which can effectively improve the stability and service life of the battery cell.

[0005] In a first aspect, an embodiment of the present application provides a battery cell, comprising a shell, a first electrode lead-out member, and at least one electrode assembly; the shell has a wall portion; the first electrode lead-out member is arranged in the shell; the electrode assembly is arranged in the shell, the electrode assembly comprising a main body portion and a first electrode tab, the first electrode tab being connected to one end of the main body portion facing the wall portion; wherein the first electrode tab comprises a root area and a weld print area connected to each other, the root area being connected to the main body portion, the weld print area comprising a first area and a second area, the first area being connected to the root area through the second area, the weld print area having a plurality of weld print grooves formed on a surface on one side in a thickness direction of the wall portion, the sum of the areas of all the weld print grooves per unit area in the first area being greater than the sum of the areas of all the weld print grooves per unit area in the second area, the weld print area being welded to the first electrode lead-out member to form a first weld print portion, and the first area being connected to and surrounding the outer side of the first weld print portion.

[0006] In the above technical solution, a plurality of weld imprint grooves are formed on the surface of one side of the weld imprint area of ​​the first pole tab in the thickness direction of the wall portion, and the first area of ​​the weld imprint area is a structure interconnected with the root area of ​​the first pole tab through the second area, wherein the sum of the areas of all weld imprint grooves within a unit area of ​​the first area is set to be greater than the sum of the areas of all weld imprint grooves within a unit area of ​​the second area, and the first area of ​​the weld imprint area is set to be connected to and surround the first weld imprint portion, so that the density of the weld imprint grooves increases from the root area to the first area of ​​the weld imprint area of ​​the first pole tab, so as to realize a structure in which the overall hardness and compaction density of the root area, the second area and the first area of ​​the first pole tab increase in sequence, and the first electrode lead-out is welded to the part of the weld imprint area located inside the first area to form a first weld imprint portion. The battery cell adopting this structure enables the second area to form a buffer area between the first area connected to the first weld imprint portion and the root area to alleviate the first pole tab from being connected to the main body. The phenomenon of excessive span in hardness and compaction density between the position of the first electrode lead-out and the position where the first electrode lead-out is welded and connected is reduced, thereby reducing the phenomenon of local stress concentration at the edge of the first area or the first weld print due to the pulling of the main body or the first electrode lead-out during use of the first electrode ear, which is beneficial to reducing the risk of local cracking or breakage of the first electrode ear during use. On the other hand, the structure of the first electrode ear being welded and assembled with the first electrode lead-out in an area with relatively large overall hardness and compaction density can be realized, thereby reducing the assembly gap inside the first electrode ear and between the first electrode ear and the first electrode lead-out, so as to reduce the phenomenon of cold welding or incomplete welding between the first electrode ear and the first electrode lead-out, which is beneficial to improving the welding quality and overcurrent effect between the first electrode ear and the first electrode lead-out, and thus effectively reducing the risk of unstable connection or connection failure between the first electrode lead-out and the electrode assembly during use, so as to improve the stability and service life of the battery cell.

[0007] In some embodiments, a thickness of a portion of the first region where the weld mark groove is not provided is equal to a thickness of a portion of the second region where the weld mark groove is not provided.

[0008] In the above technical solution, by setting the thickness of the first area and the second area of ​​the weld mark area in the area where the weld mark groove is not provided to be the same structure, the first area and the second area of ​​the weld mark area are made into a smooth transition structure, which is beneficial to improving the overall flatness of the weld mark area of ​​the first electrode tab. On the one hand, it can reduce the difficulty of welding and assembling the weld mark area and the first electrode lead-out member, and is beneficial to improving the welding quality between the weld mark area and the first electrode lead-out member. On the other hand, it can alleviate the stress concentration phenomenon between the first area and the second area caused by the different thicknesses of the first area and the second area in the area where the weld mark groove is not provided, which is beneficial to reducing the risk of breakage of the first electrode tab during use, thereby improving the stability and service life of the battery cell.

[0009] In some embodiments, the first zone accounts for 50%-80% of the total area of ​​all the weld impression grooves within a unit area.

[0010] In the above technical solution, on the one hand, the proportion of the sum of the areas of all weld mark grooves within the unit area in the first zone of the weld mark area is set to be greater than or equal to 50%, which is beneficial to increasing the density of the weld mark grooves in the first zone of the weld mark area, so as to improve the overall hardness and compaction density of the first zone, thereby facilitating the welding and assembly of the weld mark area and the first electrode lead-out member, and can reduce the phenomenon of cold welding or inadequate welding between the weld mark area and the first electrode lead-out member, thereby improving the welding quality and overcurrent effect between the weld mark area and the first electrode lead-out member. On the other hand, the proportion of the sum of the areas of all weld mark grooves within the unit area in the first zone of the weld mark area is set to be less than or equal to 80%, which is beneficial to reducing the difficulty of forming weld mark grooves in the first zone, and can reduce the stress concentration at the edge of the first zone during use caused by the excessive density of the weld mark grooves in the first zone, so as to reduce the risk of cracking or breaking of the first tab at the edge of the first zone.

[0011] In some embodiments, the second zone accounts for 20%-60% of the sum of the areas of all the weld impression grooves within a unit area.

[0012] In the above technical solution, on the one hand, the proportion of the second zone of the weld mark area to the sum of the areas of all weld mark grooves within a unit area is set to be greater than or equal to 20%, so that the second zone can play a better buffering role between the root zone where no weld mark groove is provided and the first zone with a larger density of weld mark grooves, so as to further reduce the first electrode ear during use due to the pulling of the main body or the first electrode lead-out piece. The phenomenon of local stress concentration occurs at the edge of the first zone, which is beneficial to further reduce the risk of local cracking or fracture of the first electrode during use. On the other hand, the proportion of the second zone of the weld mark area to the sum of the areas of all weld mark grooves within a unit area is set to be less than or equal to 60%, so that the root zone and the second zone can be better connected and transitioned, which is beneficial to alleviate the stress concentration between the second zone and the root zone caused by the excessive density of the weld mark grooves in the second zone, so as to reduce the risk of cracking or fracture at the connection position between the second zone and the root zone during use.

[0013] In some embodiments, the second region surrounds the first region.

[0014] In the above technical solution, the second area is set as a structure arranged around the first area, so that the area with a lower density of weld grooves can better protect the area with a higher density of weld grooves. On the one hand, it is convenient for the first area to be connected to the root area through the second area, which is beneficial to reducing the difficulty of forming the weld area of ​​the first electrode. On the other hand, the second area can better play a role in buffering stress between the root area and the first area, which is beneficial to further reduce the risk of cracking or breaking of the first electrode due to local stress concentration during use.

[0015] In some embodiments, the weld print area has a first surface and a second surface opposite to each other in the thickness direction of the wall portion, the first surface is formed with a plurality of the weld print grooves, the second surface is arranged to face and abut against the first electrode lead-out piece along the thickness direction of the wall portion, and the first weld print portion passes through the second surface.

[0016] In the above technical solution, the weld mark groove of the weld mark area is provided on the first surface of the weld mark area, the second surface of the weld mark area is arranged to face and abut the first electrode lead-out member, and the first weld mark portion formed by the weld mark area and the first electrode lead-out member being welded to each other is a structure passing through the second surface, so that the weld mark area is a structure in which the surface on the side not provided with the weld mark groove is welded to the first electrode lead-out member, thereby reducing the influence of the weld mark groove on the weld connection between the weld mark area and the first electrode lead-out member, which is beneficial to reducing the phenomenon of cold welding between the weld mark area and the first electrode lead-out member, thereby improving the welding quality between the weld mark area and the first electrode lead-out member.

[0017] In some embodiments, the second surface is planar.

[0018] In the above technical solution, by setting the second surface of the weld mark area facing the first electrode lead-out member to a flat plane, it is beneficial to further reduce the welding gap between the weld mark area and the first electrode lead-out member, thereby further reducing the phenomenon of cold welding between the weld mark area and the first electrode lead-out member, and further improving the welding quality between the weld mark area and the first electrode lead-out member.

[0019] In some embodiments, the weld print area further includes at least one third area, and the first area and the second area are connected through the third area; wherein the sum of the areas of all the weld print grooves per unit area of ​​the third area is greater than the sum of the areas of all the weld print grooves per unit area of ​​the second area, and the sum of the areas of all the weld print grooves per unit area of ​​the third area is less than the sum of the areas of all the weld print grooves per unit area of ​​the first area.

[0020] In the above technical solution, a third area is further connected between the first area and the second area of ​​the weld mark area, and the sum of the areas of all weld mark grooves within a unit area of ​​the third area is greater than the sum of the areas of all weld mark grooves within a unit area of ​​the second area, and the sum of the areas of all weld mark grooves within a unit area of ​​the third area is less than the sum of the areas of all weld mark grooves within a unit area of ​​the first area, so that the root area, the second area, the third area and the first area of ​​the first electrode ear are structures with increasing overall hardness and compaction density in sequence, which is conducive to further improving the buffering effect between the root area and the first area, so as to further alleviate the phenomenon that the hardness and compaction density of the first electrode ear are too large between the position where it is connected to the main body and the position where it is welded to the first electrode lead-out piece, thereby further reducing the phenomenon of local stress concentration at the edge of the first area due to the pulling of the main body or the first electrode lead-out piece during use of the first electrode ear, which is conducive to further reducing the risk of local cracking or breakage of the first electrode ear during use.

[0021] In some embodiments, the weld mark area includes a plurality of third areas, and along the direction pointing from the first area to the second area, the plurality of third areas are sequentially connected between the first area and the second area; wherein, in each adjacent two third areas, the sum of the areas of all the weld mark grooves per unit area of ​​the third area close to the first area is greater than the sum of the areas of all the weld mark grooves per unit area of ​​the third area close to the second area.

[0022] In the above technical solution, a plurality of third zones connected in sequence are arranged between the first zone and the second zone, and in each two adjacent third zones, the sum of the areas of all weld grooves within a unit area of ​​the third zone close to the first zone is greater than the sum of the areas of all weld grooves within a unit area of ​​the third zone close to the second zone, so as to realize that the area between the second zone and the first zone is a structure in which the overall hardness and compaction density increase in sequence through a plurality of third zones, thereby further enhancing the buffering effect between the second zone and the first zone, and helping to further reduce the phenomenon of local stress concentration at the edge of the first zone due to the pulling of the main body or the first electrode lead during use of the first pole ear, thereby further reducing the risk of local cracking or breakage of the first pole ear during use.

[0023] In some embodiments, the third region surrounds the outside of the first region, and the second region surrounds the outside of the third region.

[0024] In the above technical solution, by setting the third zone as a structure arranged around the first zone, and setting the second zone as a structure arranged around the third zone, the second zone, the third zone and the first zone are structures arranged around in sequence, so that the area with a lower density of weld grooves can better protect the area with a higher density of weld grooves, so that the second zone and the third zone can better play a role in buffering stress between the first zone and the root zone, which is conducive to further reducing the risk of cracking or breaking of the first pole ear due to local stress concentration during use.

[0025] In some embodiments, the root region and the weld print region are arranged and connected along an extension direction of the first tab.

[0026] In the above technical solution, by setting the root area and the weld print area as a structure arranged along the extension direction of the first pole ear, when the main body or the first electrode lead-out piece pulls the first pole ear during use, the second area can play a better buffering role on the root area and the first area in the stress transfer path, thereby further reducing the phenomenon of local stress concentration at the edge of the first area or the first weld print part due to the pulling of the main body or the first electrode lead-out piece during use of the first pole ear, which is beneficial to further reduce the risk of local cracking or breakage of the first pole ear during use.

[0027] In some embodiments, the main body has a straight area, and the straight area includes a plurality of first pole segments stacked along a first direction, the first pole ear is connected to one end of the first pole segment close to the wall portion in the thickness direction of the wall portion, and the first pole ear has two opposite first edges in the second direction, and the thickness direction of the wall portion, the first direction and the second direction are perpendicular to each other; wherein, the second area is adjacent to the root area, and the plurality of weld printing grooves adjacent to the root area in the second area are arranged along a preset trajectory line, and the preset trajectory line includes a straight line segment and two arc segments, and the straight line segment transitions to the two first edges respectively through the two arc segments.

[0028] In the above technical solution, the multiple welding grooves adjacent to the root area in the second zone are arranged along a preset trajectory line, and the preset trajectory line includes a straight line segment and two arc segments. By setting the straight line segment of the preset trajectory line to transition to the two first edges of the first pole ear opposite to each other in the second direction through two arc segments respectively, it is possible to achieve a structure in which the edge of the second zone and the two first edges of the first pole ear opposite to each other in the second direction are both arc transition structures, so as to reduce the stress concentration phenomenon at the connection position between the edge of the second zone and the first edge during use, and further alleviate the tearing phenomenon of the first pole ear at the connection position between the edge of the second zone and the first edge, so as to further reduce the risk of unstable connection or connection failure of the first electrode lead-out member and the electrode assembly during use, so as to further improve the stability and service life of the battery cell.

[0029] In some embodiments, the first electrode lead-out member is an electrode terminal disposed on the wall portion, and the electrode terminal is welded to the weld print area to form the first weld print portion.

[0030] In the above technical solution, the first electrode lead-out piece is provided as a structure of an electrode terminal mounted on the wall portion, and the electrode terminal is directly welded to the weld print area to achieve electrical connection between the electrode assembly and the first electrode lead-out piece. A battery cell adopting such a structure does not need to further provide a current collecting member or other structure for connecting the electrode terminal to the weld print area in the outer shell. On the one hand, it can improve the internal space utilization rate of the battery cell and optimize the weight of the battery cell to improve the energy density of the battery cell. On the other hand, it can shorten the flow path between the electrode assembly and the first electrode lead-out piece to reduce the internal resistance between the electrode assembly and the first electrode lead-out piece, thereby improving the flow effect between the electrode assembly and the first electrode lead-out piece and improving the performance of the battery cell.

[0031] In some embodiments, the weld print area and the first electrode lead-out member are arranged along the thickness direction of the wall portion; wherein, along the thickness direction of the wall portion, at least a portion of the first weld print portion extends from a surface of the weld print area on a side away from the first electrode lead-out member into the first electrode lead-out member.

[0032] In the above technical solution, the first weld mark portion is a structure that at least partially extends from the surface of the weld mark area on the side away from the first electrode lead-out member in the thickness direction of the wall portion to the inside of the first electrode lead-out member, so that the welding assembly between the weld mark area and the first electrode lead-out member is a structure in which welding is performed from the side of the weld mark area away from the first electrode lead-out member. A battery cell adopting such a structure can, on the one hand, reduce the difficulty of assembling the first electrode lead-out member and the first electrode tab, and can improve the welding quality between the first electrode lead-out member and the weld mark portion. On the other hand, it is convenient to realize the structure in which the first weld mark portion is a weld mark area that penetrates the entire first electrode tab in the thickness direction of the wall portion, thereby increasing the flow area between the first electrode tab and the first electrode lead-out member, thereby improving the flow effect between the first electrode tab and the first electrode lead-out member, and can alleviate the phenomenon of local incomplete welding of the first electrode tab in the thickness direction of the wall portion, thereby reducing the risk of unstable connection between the first electrode tab and the first electrode lead-out member.

[0033] In some embodiments, the first electrode lead-out member is disposed on the wall portion, and the first electrode lead-out member has a connection surface facing the weld print area in the thickness direction of the wall portion, and the connection surface abuts against the weld print area and is welded to the weld print area; wherein, in the thickness direction of the wall portion, the root area extends beyond the connection surface along the direction from the main body portion to the wall portion.

[0034] In the above technical solution, the first electrode lead-out member is arranged on the wall portion of the shell, and the connection surface of the first electrode lead-out member facing the weld print area in the thickness direction of the wall portion abuts against and is welded to the weld print area, which is conducive to reducing the assembly difficulty between the first electrode lead-out member and the weld print area, and is conducive to improving the welding quality between the first electrode lead-out member and the weld print area. Specifically, by setting the root area of ​​the first electrode lead to a structure in which the main body points to the direction of the wall portion and extends beyond the connection surface, the root area of ​​the first electrode lead can also share space with the first electrode lead-out member in the thickness direction of the wall portion, thereby improving the internal space utilization of the battery cell and thereby improving the energy density of the battery cell.

[0035] In some embodiments, the electrode assembly is a laminated structure, comprising a plurality of first pole pieces and a plurality of second pole pieces, the polarities of the first pole pieces and the second pole pieces are opposite, the first pole pieces and the second pole pieces are stacked and alternately arranged along a first direction, and the first pole ear is connected to the plurality of first pole pieces, and the first direction is perpendicular to the thickness direction of the wall portion.

[0036] In the above technical solution, the electrode assembly is a laminated structure formed by alternating and stacking multiple first pole pieces along a first direction. The electrode assembly using this structure can improve the volume energy density of the electrode assembly, so as to improve the energy density of the battery cell. The first pole ear is arranged to be a structure with increased density of the weld groove from the root area to the weld area for connecting with the first weld portion, so as to alleviate the phenomenon of the first pole ear breaking or cracking due to local stress concentration during use, thereby effectively alleviating the phenomenon of failure of part of the first pole piece or part of the second pole piece caused by the breaking or cracking of the first pole ear during use, thereby reducing the risk of a sudden drop in the voltage or energy density of the battery cell during use, so as to improve the performance and stability of the battery cell.

[0037] In some embodiments, the first electrode tab includes a plurality of electrode tab sheets arranged in a stacked manner, the plurality of electrode tab sheets are welded to form a plurality of weld imprint grooves and a second weld imprint portion is formed at a position corresponding to the weld imprint groove, the second weld imprint portion corresponds to the weld imprint groove one-to-one and is located at the bottom of the weld imprint groove, and the second weld imprint portion only connects the plurality of electrode tab sheets.

[0038] In the above technical solution, the multiple pole tabs of the first pole tab are welded and connected to form multiple welding grooves and second welding portions are formed at positions corresponding to the welding grooves, and the second welding portions are only connected to the multiple pole tabs, so that the welding grooves on the first pole tab are a structure formed by welding the multiple pole tabs stacked on the first pole tab, and the second welding portion corresponding to the bottom of each welding groove is a structure formed by pre-welding the multiple pole tabs. The battery cell adopting this structure can realize pre-welding and fixing the multiple pole tabs of the first pole tab before assembling the first pole tab and the first electrode lead-out piece. On the one hand, it can reduce the phenomenon of movement or displacement of the multiple pole tabs of the first pole tab during the process of mutual welding and assembly with the first electrode lead-out piece, thereby reducing the occurrence of misalignment between the first pole tab and the first electrode lead-out piece. The phenomenon of cold welding or partial welding of the pole tab is solved to improve the assembly quality and overcurrent effect between the first pole tab and the first electrode lead-out piece. On the other hand, since the sum of the areas of all the weld imprint grooves per unit area of ​​the first zone is set to be greater than the sum of the areas of all the weld imprint grooves per unit area of ​​the second zone, and the first zone is connected to and arranged around the first weld imprint, the second zone can also play a role in buffering stress during the mutual welding and assembly of the weld imprint zone and the first electrode lead-out piece, so as to reduce the risk of stress concentration at the edge of the first zone causing cracking or breaking of some pole tabs, thereby further reducing the risk of unstable connection or connection failure between the first electrode lead-out piece and the electrode assembly during use, so as to further improve the stability and service life of the battery cell.

[0039] In a second aspect, an embodiment of the present application further provides a battery device comprising the above-mentioned battery cell.

[0040] In a third aspect, an embodiment of the present application further provides an electrical device, comprising the above-mentioned battery cell, wherein the battery cell is used to provide electrical energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0042] Figure 1 A schematic structural diagram of a vehicle provided in some embodiments of the present application; Figure 2 An exploded view of the structure of a battery device provided in some embodiments of the present application; Figure 3 A schematic structural diagram of a battery cell provided in some embodiments of the present application; Figure 4 An exploded view of the structure of a battery cell provided in some embodiments of the present application; Figure 5 A partial cross-sectional view of a battery cell provided in some embodiments of the present application; Figure 6 A schematic diagram of the assembly of the electrode lead-out member and the first electrode tab provided in some embodiments of the present application; Figure 7 A partial cross-sectional view of the assembled electrode lead-out member and the first electrode tab provided in some embodiments of the present application; Figure 8 for Figure 7 A partial enlarged view of the first tab at point A shown; Figure 9 A cross-sectional view of the main body of the electrode assembly provided in some embodiments of the present application, taken perpendicularly to the thickness direction of the wall; Figure 10 A cross-sectional view of the main body of an electrode assembly provided in some further embodiments of the present application, taken in a direction perpendicular to the thickness of the wall.

[0043] Icons: 1000-vehicle; 100-battery device; 10-housing; 11-first housing; 12-second housing; 20-battery cell; 21-housing; 211-wall; 2111-first electrode lead-out hole; 212-housing; 2121-opening; 213-end cap; 22-first electrode lead-out member; 221-electrode terminal; 2211-connecting surface; 23-electrode assembly; 23a-straight area; 23b-bending area; 231-main body; 2311-first pole piece; 2311a-first pole segment; 2311b-first bending segment; 2312-second pole piece; 2312a-second pole segment; 2312b-second bending segment; 2313-isolator; 232- First electrode tab; 232a-electrode tab sheet; 2321-root area; 2322-weld stamp area; 23221-first area; 23222-second area; 23223-third area; 23224-weld stamp groove; 23224a-slot; 23225-first surface; 23226-second surface; 23227-preset trajectory line; 23227a-straight line segment; 23227b-arc segment; 2323-second weld stamp portion; 2324-first edge; 233-second electrode tab; 24-first weld stamp portion; 25-second electrode lead-out member; 26-pressure relief component; 200-controller; 300-motor; X-thickness direction of the wall; Y-first direction; Z-second direction; R-winding direction. DETAILED DESCRIPTION

[0044] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0045] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0046] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments.

[0047] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0048] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0049] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.

[0050] The term "plurality" used in this application refers to two or more (including two).

[0051] In the embodiment of the present application, the battery cell may be a secondary battery. A secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0052] The battery cells can be lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-hydrogen batteries, nickel-cadmium batteries, lead-acid batteries, etc., which are not limited in the embodiments of the present application.

[0053] A battery cell typically includes an electrode assembly. This assembly consists of a positive electrode, a negative electrode, and a separator. During the charge and discharge process, active ions (such as lithium ions) move back and forth between the positive and negative electrodes. The separator, placed between the positive and negative electrodes, prevents short circuits to a certain extent while allowing the active ions to pass through.

[0054] 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.

[0055] As an example, the positive electrode current collector has two surfaces facing each other in its thickness direction, and the positive electrode active material is provided on either or both of the two facing surfaces of the positive electrode current collector.

[0056] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, the metal foil may include silver-plated aluminum, silver-plated stainless steel, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, or titanium. A composite current collector may include a polymer base layer and a metal layer. The composite current collector can be formed by forming a metal material (such as aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy) on a polymer substrate (such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0057] As an example, the positive electrode active material may include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides, and their respective modified compounds. However, the present application is not limited to these materials, and other traditional 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-containing phosphates may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon. Examples of lithium transition metal oxides may 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, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also referred to as NCM 333 )、LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM 523 )、LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 )、LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM622 )、LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 )), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O2) and its modified compounds, etc.

[0058] In some embodiments, a positive electrode may utilize a metal foam. The metal foam may include nickel foam, copper foam, aluminum foam, alloy foam, or the like. When a metal foam is used as the positive electrode, the surface of the metal foam may or may not include a positive electrode active material. For example, a lithium source material, potassium metal, or sodium metal may be filled or / and deposited within the metal foam, where the lithium source material is lithium metal and / or a lithium-rich material.

[0059] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0060] As examples, the negative electrode current collector can be a metal foil, metal foam, or composite current collector. For example, the metal foil can be silver-treated aluminum or stainless steel, copper, aluminum, nickel, carbon electrode, or titanium. The metal foam can be nickel foam, copper foam, aluminum foam, or alloy foam. The composite current collector can include a polymer base layer and a metal layer. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, or silver alloy) onto a polymer substrate (such as polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, or polyethylene).

[0061] 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.

[0062] As an example, the negative electrode current collector has two surfaces facing each other in its thickness direction, and the negative electrode active material is provided on either or both of the two facing surfaces of the negative electrode current collector.

[0063] As an example, the negative electrode active material may adopt the negative electrode active material for battery cells that is well known in the art. 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, lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0064] In some embodiments, the material of the positive electrode current collector may be aluminum, and the material of the negative electrode current collector may be copper.

[0065] In some embodiments, the electrode assembly further includes a separator disposed between the positive electrode and the negative electrode.

[0066] In some embodiments, the separator is a separator membrane. There are many types of separator membranes, and any known separator membrane with a porous structure having good chemical stability and mechanical stability can be selected.

[0067] As an example, the separator can be made of at least one of fiberglass, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film. In the case of a multi-layer composite film, the materials of each layer can be the same or different. The separator can be a separate component positioned between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes.

[0068] In some embodiments, the separator is a solid electrolyte, which is disposed between the positive electrode and the negative electrode and serves to transport ions and isolate the positive and negative electrodes.

[0069] In some embodiments, the battery cell further includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel, or solid. Liquid electrolytes include an electrolyte salt and a solvent.

[0070] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium bisoxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.

[0071] In some embodiments, the solvent may include at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, cyclopentane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone. The solvent may also be an ether solvent. The ether solvent may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether and crown ether.

[0072] Among them, the gel electrolyte includes a skeleton network with a polymer as the electrolyte, combined with an ionic liquid-lithium salt.

[0073] Among them, solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0074] As an example, the polymer solid electrolyte can be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, a single ion polymer, polyionic liquid-lithium salt, cellulose, etc.

[0075] As an example, the inorganic solid electrolyte may include an oxide solid electrolyte (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON film), a sulfide solid electrolyte (crystalline lithium superion conductor (lithium germanium phosphosulfide, silver germanium sulfide), amorphous sulfide) and one or more of a halide solid electrolyte, a nitride solid electrolyte and a hydride solid electrolyte.

[0076] As an example, a composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to a polymer solid electrolyte.

[0077] In some embodiments, the electrode assembly is a wound structure, wherein the positive electrode sheet and the negative electrode sheet are wound into the wound structure.

[0078] In some embodiments, the electrode assembly is a laminated structure.

[0079] As an example, multiple positive electrode sheets and multiple negative electrode sheets can be provided respectively, and the multiple positive electrode sheets and the multiple negative electrode sheets can be alternately stacked.

[0080] As an example, a plurality of positive electrode sheets may be provided, and the negative electrode sheet may be folded to form a plurality of stacked folded segments, with a positive electrode sheet being sandwiched between adjacent folded segments.

[0081] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form a plurality of folded segments that are stacked.

[0082] As an example, a plurality of separators may be provided, each of which is disposed between any adjacent positive electrode sheets or negative electrode sheets.

[0083] As an example, the separator may be provided continuously, and may be provided between any adjacent positive electrode sheets or negative electrode sheets by folding or winding.

[0084] In some embodiments, the shape of the electrode assembly can be flat or polygonal.

[0085] In some embodiments, the electrode assembly is provided with tabs that can conduct current from the electrode assembly. The tabs include a positive tab and a negative tab.

[0086] In some embodiments, a battery cell may include a housing. The housing is used to encapsulate components such as the electrode assembly and electrolyte. The housing may be a steel housing, an aluminum housing, a plastic housing (e.g., polypropylene), a composite metal housing (e.g., a copper-aluminum composite housing), or an aluminum-plastic film.

[0087] As an example, the battery cell may be a prismatic battery cell, a soft-pack battery cell, or a battery cell of another shape. Prismatic battery cells include but are not limited to square-shell battery cells, blade-shaped battery cells, and polygonal prismatic batteries, such as hexagonal prismatic batteries.

[0088] The battery device mentioned in the embodiments of the present application may include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly may include multiple battery cells, which are connected in series, parallel, or hybrid via a busbar.

[0089] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells. For example, the battery cell assembly may be a battery module, which is formed by arranging and securing multiple battery cells to form a single module. For example, a battery module may be formed by bundling multiple battery cells using cable ties.

[0090] In some embodiments, the battery device may be a battery pack, which includes a case and one or more battery cell assemblies, wherein the battery cell assemblies are housed in the case.

[0091] As an example, the battery cell assembly may be a battery module, and the battery cell assembly may be accommodated in the box by fixing the battery module in the box.

[0092] As an example, the battery cell assembly may also be housed in the box by directly fixing the plurality of battery cells to the box.

[0093] As an example, the housing may include a first housing body and a second housing body. The first and second housing bodies engage to form an enclosed space within the housing to house the battery cell assembly. Enclosed here means covered or closed, and can be either sealed or unsealed. The first housing body may be a top cover or a bottom plate.

[0094] As an example, the box may include a top cover, a frame, and a bottom plate, wherein the top cover and the bottom plate are respectively connected to the frame to form a closed space inside the box to accommodate the battery cell assembly.

[0095] As an example, the box body can be used as a part of the chassis structure of the vehicle. For example, the top cover of the box body can become at least a part of the floor of the vehicle, or the frame of the box body can become at least a part of the crossbeam and longitudinal beam of the vehicle.

[0096] In some embodiments, the battery device refers to an energy storage device, which includes a box with a door on at least one side. The energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0097] Batteries, with their outstanding advantages such as high energy density, low environmental pollution, high power density, long service life, wide adaptability, and low self-discharge coefficient, are a crucial component of today's new energy development. The development of battery technology requires simultaneous consideration of multiple design factors, including performance parameters such as energy density, cycle life, discharge capacity, and charge / discharge rate. Furthermore, battery device reliability must be considered.

[0098] For a general battery cell, the battery cell includes a shell and an electrode assembly housed in the shell. Correspondingly, the shell is also provided with electrode terminals, and a current collecting component is provided in the shell. The current collecting component is welded to the electrode terminal, and the current collecting component is welded to the pole ear to achieve electrical connection between the electrode assembly and the electrode terminal, so that the input or output of electrical energy of the battery cell can be achieved through the electrode terminal. In the related art, since the pole ear of the electrode assembly is a structure formed by stacking and folding a plurality of pole ear sheets with the same polarity, in order to improve the welding quality between the pole ear and the current collecting component, the plurality of pole ear sheets of the pole ear are usually first folded and ultrasonically pre-welded to form a plurality of pole ear sheets of the pole ear. After the whole is assembled, it is welded to the current collecting component, so as to reduce the phenomenon of misalignment and movement of the multiple pole tabs of the pole tab during the welding process with the current collecting component, so as to reduce the risk of cold welding between the pole tab and the current collecting component. However, the battery cell with this structure will cause the strength and hardness of some areas of the pole tab to be greater after the multiple pole tabs of the pole tab are gathered and ultrasonically pre-welded, so that the edge of the pole tab through the ultrasonic pre-welded area is prone to local stress concentration during use, which can easily cause the pole tab to crack or even break during use, resulting in the risk of unstable connection or connection failure between the electrode terminal and the electrode assembly during use, which is not conducive to improving the stability and service life of the battery cell.

[0099] Based on the above considerations, in order to solve the problem of low stability and short service life of battery cells, an embodiment of the present application provides a battery cell, which includes a housing, a first electrode lead-out member, and at least one electrode assembly. The housing has a wall portion. The first electrode lead-out member is disposed in the housing. The electrode assembly is disposed in the housing, and the electrode assembly includes a main body and a first tab, the first tab being connected to one end of the main body facing the wall portion. The first tab includes a root region and a weld mark region that are interconnected, the root region being connected to the main body, the weld mark region including a first region and a second region, the first region being connected to the root region via the second region, the weld mark region having a plurality of weld mark grooves formed on a surface on one side in the thickness direction of the wall portion, the sum of the areas of all weld mark grooves per unit area in the first region being greater than the sum of the areas of all weld mark grooves per unit area in the second region, the weld mark region being welded to the first electrode lead-out member to form a first weld mark portion, and the first region being connected to and surrounding the outer side of the first weld mark portion.

[0100] In a battery cell of this structure, a plurality of weld grooves are formed on the surface of one side of the weld mark area of ​​the first pole tab in the thickness direction of the wall portion, and the first area of ​​the weld mark area is a structure interconnected with the root area of ​​the first pole tab through the second area, wherein the sum of the areas of all weld grooves within a unit area of ​​the first area is set to be greater than the sum of the areas of all weld grooves within a unit area of ​​the second area, and the first area of ​​the weld mark area is set to be connected to and surround the first weld mark portion, so that the density of the weld grooves increases from the root area to the first area of ​​the weld mark area of ​​the first pole tab, so as to realize a structure in which the overall hardness and compaction density of the root area, the second area and the first area of ​​the first pole tab increase in sequence, and the first electrode lead-out is welded to the part of the weld mark area located inside the first area to form a first weld mark portion. On the one hand, a battery cell with this structure enables the second area to form a buffer area between the first area connected to the first weld mark portion and the root area to alleviate the first pole tab from contacting the main body. The phenomenon of excessive span in hardness and compaction density between the connection position and the position where the first electrode lead is welded to the first electrode lead-out piece can reduce the phenomenon of local stress concentration at the edge of the first area or the first weld print due to the pulling of the main body or the first electrode lead-out piece during use of the first electrode ear, which is beneficial to reducing the risk of local cracking or breakage of the first electrode ear during use. On the other hand, the structure of the first electrode ear being welded and assembled with the first electrode lead-out piece in an area with relatively large overall hardness and compaction density can be realized, thereby reducing the assembly gap inside the first electrode ear and between the first electrode ear and the first electrode lead-out piece, so as to reduce the phenomenon of cold welding or incomplete welding between the first electrode ear and the first electrode lead-out piece, which is beneficial to improving the welding quality and overcurrent effect between the first electrode ear and the first electrode lead-out piece, and thus can effectively reduce the risk of unstable connection or connection failure between the first electrode lead-out piece and the electrode assembly during use, so as to improve the stability and service life of the battery cell.

[0101] The battery cells disclosed in the embodiments of this application can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft. A power supply system comprising the battery cells and battery devices disclosed in this application can be used to construct such electrical devices. This helps alleviate issues with unstable or failed connections of the battery cells during use, thereby improving the stability and service life of the battery cells.

[0102] The embodiments of the present application provide an electrical device that uses a battery cell or battery device as a power source. The electrical device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery-powered vehicle, an electric car, a ship, a spacecraft, etc. The electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc. The spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0103] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device according to an embodiment of the present application.

[0104] Please refer to Figure 1 , Figure 1 A schematic structural diagram of a vehicle 1000 provided for some embodiments of the present application. The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery device 100 is provided inside the vehicle 1000. The battery device 100 may be provided at the bottom of the vehicle 1000, or at the head of the vehicle 1000, or at the tail of the vehicle 1000. The battery device 100 may be used to power the vehicle 1000. For example, the battery device 100 may serve as an operating power source or a power source for the vehicle 1000. The vehicle 1000 may further include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to power the motor 300, for example, to meet the power requirements for starting, navigating and driving the vehicle 1000.

[0105] In some embodiments of the present application, the battery device 100 can not only serve as the operating power source or usage power source of the vehicle 1000, but also serve as the driving power source of the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0106] 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 the present application. Figure 3 The battery device 100 includes a housing 10 and a battery cell 20 , wherein the battery cell 20 is accommodated in the housing 10 .

[0107] The housing 10 is used to provide assembly space for the battery cells 20 and can adopt a variety of structures. In some embodiments, the housing 10 can include a first housing body 11 and a second housing body 12. The first housing body 11 and the second housing body 12 cover each other, and the first housing body 11 and the second housing body 12 jointly define an assembly space for accommodating the battery cells 20. The second housing body 12 can be a hollow structure with one end open, and the first housing body 11 can be a plate-like structure. The first housing body 11 covers the open side of the second housing body 12, so that the first housing body 11 and the second housing body 12 jointly define the assembly space. The first housing body 11 and the second housing body 12 can also be hollow structures with one end open, and the open side of the first housing body 11 covers the open side of the second housing body 12.

[0108] Of course, the box body 10 formed by the first box body 11 and the second box body 12 can be in various shapes, such as a cylinder, a cuboid or a cube. Figure 2 In the embodiment, the box body 10 is in the shape of a cuboid.

[0109] 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, the multiple battery cells 20 can be connected in series, in parallel, or in a hybrid configuration. A hybrid configuration refers to a combination of series and parallel configurations within the multiple battery cells 20. The multiple battery cells 20 can be directly connected in series, in parallel, or in a hybrid configuration, and then the entire assembly formed by the multiple battery cells 20 is housed within the housing 10. Alternatively, the battery device 100 can be constructed by first connecting multiple battery cells 20 in series, in parallel, or in a hybrid configuration to form a battery module, which is then further connected in series, in parallel, or in a hybrid configuration to form a single assembly, which is then housed within the housing 10.

[0110] In some embodiments, the battery device 100 may further include other structures. For example, the battery device 100 may further include a busbar component, which is used to connect the multiple battery cells 20 to achieve electrical connection between the multiple battery cells 20 .

[0111] Each battery cell 20 may be a secondary battery or a primary battery; it may also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 20 may be in the shape of a cuboid, a prism, or other shapes. For example, Figure 3 In the figure, the battery cell 20 is a rectangular parallelepiped structure.

[0112] According to some embodiments of the present application, referring to Figure 3 , and please refer to Figure 4 、 Figure 5 、 Figure 6 、 Figure 7 and Figure 8 , Figure 4 This is an exploded view of the structure of the battery cell 20 provided in some embodiments of the present application. Figure 5 A partial cross-sectional view of a battery cell 20 provided in some embodiments of the present application is shown. Figure 6 This is a schematic diagram of the assembly of the electrode lead-out member and the first electrode tab 232 provided in some embodiments of the present application. Figure 7 This is a partial cross-sectional view of the electrode lead-out member and the first electrode tab 232 after assembly provided in some embodiments of the present application. Figure 8 for Figure 7A partial enlarged view of point A of the first electrode tab 232 is shown. The present application provides a battery cell 20, comprising a housing 21, a first electrode lead 22, and at least one electrode assembly 23. The housing 21 has a wall 211. The first electrode lead 22 is disposed within the housing 21. The electrode assembly 23 is disposed within the housing 21 and comprises a main body 231 and a first electrode tab 232. The first electrode tab 232 is connected to one end of the main body 231 facing the wall 211. The first electrode tab 232 includes a root area 2321 and a weld print area 2322 that are connected to each other. The root area 2321 is connected to the main body 231. The weld print area 2322 includes a first area 23221 and a second area 23222. The first area 23221 is connected to the root area 2321 through the second area 23222. The weld print area 2322 is formed with a plurality of weld print grooves 23224 on the surface of one side in the thickness direction X of the wall portion. The sum of the areas of all weld print grooves 23224 per unit area of ​​the first area 23221 is greater than the sum of the areas of all weld print grooves 23224 per unit area of ​​the second area 23222. The weld print area 2322 is welded to the first electrode lead-out member 22 to form a first weld print portion 24, and the first area 23221 is connected to and surrounds the outer side of the first weld print portion 24.

[0113] The housing 21 can also be used to contain an electrolyte, such as an electrolyte solution. The housing 21 can have various structural forms, such as a rectangular parallelepiped. Similarly, the housing 21 can be made of various materials, such as copper, iron, aluminum, steel, or aluminum alloy.

[0114] In some embodiments, the housing 21 may be a sealed structure or a non-sealed structure. For example, when the housing 21 is a sealed structure, the housing 21 may protect the electrode assembly 23 and, to a certain extent, prevent electrolyte leakage. When the housing 21 is a non-sealed structure, the housing 21 may protect the electrode assembly 23. A sealing bag may be provided between the housing 21 and the electrode assembly 23 to encapsulate the electrode assembly 23 and the electrolyte.

[0115] Optionally, the outer shell 21 may include a shell 212 and an end cover 213, wherein a accommodating cavity is formed inside the shell 212, and the accommodating cavity is used to accommodate the electrode assembly 23, and the accommodating cavity has an opening 2121, that is, the shell 212 is a hollow structure with an opening 2121 formed at one end, and the end cover 213 covers the opening 2121 of the shell 212 and forms a sealed connection to form a sealed space for accommodating the electrode assembly 23 and the electrolyte.

[0116] The housing 212 includes a bottom wall and a side wall. The bottom wall is arranged opposite to the end cover 213 . The side wall is arranged around the bottom wall. One end of the side wall is connected to the bottom wall, and the other end is enclosed to form an opening 2121 .

[0117] It should be noted that the wall portion 211 of the housing 21 may be the end cover 213 of the housing 21 or a wall of the shell 212 of the housing 21. Figure 3 and Figure 4 In the embodiment, the wall portion 211 is the end cap 213. Of course, the structure of the battery cell 20 is not limited thereto. In other embodiments, the wall portion 211 may be a bottom wall of the housing 212 and the end cap 213, or a side wall of the housing 212 and the end cap 213 that are adjacent to and connected to each other.

[0118] The shell 212 can be in various shapes, such as a rectangular parallelepiped or a prismatic structure. The shape of the shell 212 can be determined according to the specific shape of the electrode assembly 23. For example, if the electrode assembly 23 is a rectangular parallelepiped structure, a shell 212 with a rectangular parallelepiped structure can be selected. Of course, the structure of the end cap 213 can also be various, such as a plate-like structure or a hollow structure with one end open. For example, in Figure 3 and Figure 4 In the embodiment, the shell 212 is a rectangular parallelepiped structure, and correspondingly, the end cover 213 is a rectangular plate-shaped structure.

[0119] Of course, it is understandable that the shell 21 is not limited to the above structure. The shell 21 may also be other structures. For example, the shell 21 may include a shell body 212 and two end covers 213. The shell body 212 is a hollow structure with openings 2121 formed on two opposite sides. One end cover 213 corresponds to an opening 2121 of the shell body 212 and forms a sealed connection to form a sealed space for accommodating the electrode assembly 23 and the electrolyte. That is, the shell body 212 has openings 2121 formed on two opposite sides, and the two end covers 213 are respectively covered on both sides of the shell body 212 to close the corresponding openings 2121.

[0120] In the examples of this application, see Figure 4 and Figure 5 As shown, the electrode assembly 23 includes a main body 231, a first pole ear 232 and a second pole ear 233. The main body 231 is the main component of the electrode assembly 23 for generating chemical reactions inside the battery cell 20. The polarities of the first pole ear 232 and the second pole ear 233 are opposite, that is, the first pole ear 232 and the second pole ear 233 are respectively the positive pole ear and the negative pole ear of the electrode assembly 23, and the first pole ear 232 and the second pole ear 233 are both connected to the main body 231 and are arranged at intervals.

[0121] The main body 231 of the electrode assembly 23 includes a first electrode piece 2311, a second electrode piece 2312 and a separator 2313. The polarities of the first electrode piece 2311 and the second electrode piece 2312 are opposite, that is, the first electrode piece 2311 and the second electrode piece 2312 are respectively the positive electrode piece and the negative electrode piece of the electrode assembly 23. Correspondingly, the first electrode ear 232 is connected to the first electrode piece 2311, and the second electrode ear 233 is connected to the second electrode piece 2312. Optionally, the main body 231 of the electrode assembly 23 The structure can be of various types. The main body 231 of the electrode assembly 23 can be a wound structure formed by winding the first electrode piece 2311, the second electrode piece 2312 and the isolation piece 2313, or it can be a laminated structure formed by alternatingly stacking the first electrode piece 2311, the second electrode piece 2312 and the isolation piece 2313. The isolation piece 2313 is arranged between the first electrode piece 2311 and the second electrode piece 2312 to insulate and isolate the first electrode piece 2311 and the second electrode piece 2312.

[0122] Illustratively, the isolation member 2313 is an isolation membrane, and a main material of the isolation membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride.

[0123] Optionally, in Figure 4 and Figure 5 In the embodiment, the first pole tab 232 and the second pole tab 233 are 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 pole tab 232 and the second pole tab 233 can also be a structure that is respectively connected to the two ends of the main body 231 in the thickness direction X of the wall.

[0124] Exemplarily, the first tab 232 is connected to one end of the first pole piece 2311 close to the wall 211 in the thickness direction X of the wall, and the second tab 233 is connected to one end of the second pole piece 2312 close to the wall 211 in the thickness direction X of the wall.

[0125] Among them, combined Figure 6 、 Figure 7 and Figure 8As shown, the first pole tab 232 of the electrode assembly 23 is a multi-layer metal foil structure connected to one end of the first pole piece 2311 in the thickness direction X of the wall, that is, the first pole tab 232 includes a plurality of pole tab sheets 232a arranged in a stacked manner. Correspondingly, the second pole tab 233 of the electrode assembly 23 is also a multi-layer metal foil structure connected to one end of the second pole piece 2312 in the thickness direction X of the wall. It should be noted that the first pole tab 232 and the first pole piece 2311 can be structures that are separately arranged, for example, the first pole tab 232 is welded to the first current collector of the first pole piece 2311. Of course, the first pole tab 232 and the first pole piece 2311 can also be an integrally formed structure, for example, the first pole tab 232 and the first current collector of the first pole piece 2311 are structures formed by integrally cutting the same metal foil to form the first pole tab 232 and the first current collector; similarly, the second pole tab 233 and the second pole piece 2312 can be structures that are separately arranged, for example, the second pole tab 233 is welded to the second current collector of the second pole piece 2312. Of course, the second pole tab 233 and the second pole piece 2312 can also be an integrally formed structure, for example, the second current collector of the second pole tab 233 and the second pole piece 2312 are structures formed by integrally cutting the same metal foil to form the second pole tab 233 and the second current collector.

[0126] Optionally, the number of electrode assemblies 23 contained in the housing 21 may be one or more. Figure 4 and Figure 5 In the embodiment, the outer shell 21 of the battery cell 20 contains two electrode assemblies 23, and the two electrode assemblies 23 are stacked along the first direction Y. Of course, in other embodiments, the number of electrode assemblies 23 contained in the outer shell 21 of the battery cell 20 can be three, four, five or six, etc.

[0127] In the embodiment of the present application, the electrode assembly 23 has a straight area 23a, that is, the straight area 23a is the straight portion of the main body 231 of the electrode assembly 23. For example, referring to Figure 9 As shown, Figure 9 This is a cross-sectional view of the main body 231 of the electrode assembly 23 provided in some embodiments of the present application, perpendicular to the thickness direction X of the wall. If the electrode assembly 23 is a laminated structure, the main body 231 of the electrode assembly 23 is a straight area 23a as a whole, that is, the main body 231 of the electrode assembly 23 only includes the straight area 23a. Of course, if the electrode assembly 23 is a wound structure, refer to Figure 10 As shown, Figure 10A cross-sectional view of the main body 231 of the electrode assembly 23 provided in some further embodiments of the present application is perpendicular to the thickness direction X of the wall, and the winding center axis of the electrode assembly 23 extends along the thickness direction X of the wall. Correspondingly, the main body 231 also has two bending areas 23b, and the two bending areas 23b are respectively connected to the opposite ends of the straight area 23a in the second direction Z, and the thickness direction X of the wall, the first direction Y and the second direction Z are perpendicular to each other.

[0128] The first pole piece 2311 includes a first pole segment 2311a located in the straight area 23a, and the second pole piece 2312 includes a second pole segment 2312a located in the straight area 23a. The first pole segment 2311a and the second pole segment 2312a are stacked and alternately arranged along the first direction Y. Correspondingly, each pole ear piece 232a is connected to an end of the first pole segment 2311a facing the wall portion 211 in the thickness direction X of the wall portion.

[0129] It should be noted that, see Figure 9 As shown, if the electrode assembly 23 is a laminated structure, the electrode assembly 23 includes a plurality of first pole pieces 2311 and a plurality of second pole pieces 2312, and the first pole pieces 2311 and the second pole pieces 2312 are alternately and stacked along the first direction Y. Correspondingly, the first pole segment 2311a is the first pole piece 2311, and each first pole segment 2311a is connected to a pole ear piece 232a at one end facing the wall portion 211 in the thickness direction X of the wall portion, and the second pole segment 2312a is the second pole piece 2312; if the electrode assembly 23 is a wound structure, see Figure 10 As shown, the first electrode segment 2311a is the straight portion of the first electrode piece 2311 located within the straight region 23a, and the second electrode segment 2312a is the straight portion of the second electrode piece 2312 located within the straight region 23a. Correspondingly, the first electrode piece 2311 also includes a first bent section 2311b located within the bent region 23b, and the second electrode piece 2312 also includes a second bent section 2312b located within the bent region 23b. In the winding direction R of the electrode assembly 23, the first bent section 2311b connects two adjacent first electrode segments 2311a, and the first bent sections 2311b and the first electrode segments 2311a are alternately arranged. Similarly, in the winding direction R of the electrode assembly 23, the second bent section 2312b connects two adjacent second electrode segments 2312a, and the second bent sections 2312b and the second electrode segments 2312a are alternately arranged.

[0130] The first pole ear 232 includes a root area 2321 and a weld print area 2322 that are interconnected. The root area 2321 is connected to the main body 231. That is, the first pole ear 232 is divided into two areas, namely the root area 2321 and the weld print area 2322 that are interconnected. The weld print area 2322 is a structure that is interconnected with the main body 231 of the electrode assembly 23 through the root area 2321, that is, the first pole ear 232 is a structure in which the root area 2321 and the first pole piece 2311 are interconnected.

[0131] The weld imprint area 2322 includes a first area 23221 and a second area 23222. The first area 23221 is connected to the root area 2321 through the second area 23222. In other words, the second area 23222 is adjacent to the root area 2321, that is, the second area 23222 is adjacent to and directly connected to the root area 2321, and the second area 23222 is connected between the first area 23221 and the root area 2321. It should be noted that the first area 23221 and the second area 23222 can be a directly connected structure or an indirectly connected structure. For example, see Figure 6 As shown, a third area 23223 is further formed on the weld print area 2322 , and the first area 23221 and the second area 23222 are interconnected via the third area 23223 .

[0132] See also Figure 7 and Figure 8 As shown, a plurality of weld grooves 23224 are formed on the surface of the weld area 2322 on one side in the thickness direction X of the wall portion. That is, the plurality of pole tab sheets 232a of the first pole tab 232 are welded to each other in the weld area 2322, and the plurality of pole tab sheets 232a are welded to form a plurality of weld grooves 23224 arranged at intervals on the surface of the weld area 2322 along the thickness direction X of the wall portion.

[0133] In the examples of this application, please continue to refer to Figure 7 and Figure 8As shown, the weld area 2322 has a first surface 23225 and a second surface 23226 opposite to each other in the thickness direction X of the wall portion, and a plurality of tabs 232a are welded and connected to form a plurality of weld grooves 23224 on the weld area 2322. The weld grooves 23224 are located between the first surface 23225 and the second surface 23226, and the weld grooves 23224 pass through the first surface 23225 and form notches 23224a on the first surface 23225. The weld grooves 23224 are groove structures formed on the first surface 23225 by welding a plurality of tabs 232a, such as ultrasonic welding. Accordingly, multiple pole tabs 232a are welded and connected to form multiple second weld prints 2323, and the second weld prints 2323 connect the multiple pole tabs 232a. The second weld prints 2323 are arranged in a one-to-one correspondence with the weld print grooves 23224. A second weld print 2323 is formed at the bottom of each weld print groove 23224, that is, the bottom wall of each weld print groove 23224 is at least a part of a second weld print 2323, so as to form a second weld print 2323 at the bottom of each weld print groove 23224, that is, in the thickness direction X of the wall, a second weld print 2323 is formed at the position corresponding to each weld print groove 23224.

[0134] It should be noted that the parts of the multiple pole tabs 232a of the first pole tab 232 in the root area 2321 are a structure in which they are stacked on each other and are not fixedly connected, and the part of the pole tab 232a located in the root area 2321 is connected to the first pole piece 2311 at one end away from the weld print area 2322, while the parts of the multiple pole tabs 232a of the first pole tab 232 in the weld print area 2322 are a structure in which they are fixedly connected to each other through the second weld print portion 2323.

[0135] It should be noted that the second weld mark portion 2323 is a region where the plurality of tabs 232 a are welded together to form a mutual fusion or a region where a weld mark is formed by welding.

[0136] The sum of the areas of all weld mark grooves 23224 within a unit area of ​​the first zone 23221 is greater than the sum of the areas of all weld mark grooves 23224 within a unit area of ​​the second zone 23222. That is, in the projection plane perpendicular to the thickness direction X of the wall portion, the sum of the areas of the orthographic projections of the groove wall surfaces of all weld mark grooves 23224 within a unit area of ​​the first zone 23221 is greater than the sum of the areas of the orthographic projections of the groove wall surfaces of all weld mark grooves 23224 within a unit area of ​​the second zone 23222. That is, the proportion of the sum of the areas of the orthographic projections of the groove wall surfaces of all weld mark grooves 23224 within a unit area of ​​the first zone 23221 is greater than the proportion of the orthographic projections of the groove wall surfaces of all weld mark grooves 23224 within a unit area of ​​the second zone 23222. Similarly, the sum of the areas of the notches 23224a of all the weld grooves 23224 in the first zone 23221 per unit area is greater than the sum of the areas of the notches 23224a of all the weld grooves 23224 in the second zone 23222 per unit area, that is, the sum of the areas of the notches 23224a of all the weld grooves 23224 in the first zone 23221 per unit area is greater than the sum of the areas of the notches 23224a of all the weld grooves 23224 in the second zone 23222 per unit area. It should be noted that when comparing the sum of the areas of the weld grooves 23224 in the first zone 23221 and the second zone 23222 per unit area, the unit of unit area is the same.

[0137] The weld print area 2322 is welded to the first electrode lead-out member 22 to form a first weld print portion 24, and the first area 23221 is connected to and surrounds the outside of the first weld print portion 24. That is, the first electrode tab 232 is a structure in which the weld print area 2322 and the first electrode lead-out member 22 are welded to each other, and the first weld print portion 24 is formed accordingly, so that part of the first weld print portion 24 is embedded in the weld print area 2322, and part of the first weld print portion 24 is embedded in the first electrode lead-out member 22. Correspondingly, the first area 23221 with a relatively large density of weld print grooves 23224 in the weld print area 2322 of the first electrode tab 232 is a structure that is arranged around the first weld print portion 24 and is directly connected to the first weld print portion 24, so that the part of the first weld print portion 24 located in the weld print area 2322 is a structure connected to other parts of the first electrode tab 232 through the first area 23221. It should be noted that the second weld portion 2323 and the weld groove 23224 in the weld area 2322 are structures formed by pre-welding the multiple electrode tabs 232a of the first electrode tab 232 before the first electrode tab 232 and the first electrode lead-out member 22 are welded and assembled, and a plurality of weld grooves 23224 are also formed in the area where the weld area 2322 is welded to the first electrode lead-out member 22, and the area of ​​all weld grooves 23224 in the unit area of ​​the weld area 2322 and the first electrode lead-out member 22 is equal to the sum of the areas of all weld grooves 23224 in the unit area of ​​the first area 23221, that is, the weld area 2322 and the first electrode lead-out member 2 The density of the weld grooves 23224 in the welded area is similar to the density of the weld grooves 23224 in the first area 23221. After the weld zone 2322 is welded to the first electrode lead-out member 22 to form the first weld portion 24, the weld grooves 23224 in the welded area of ​​the weld zone 2322 and the first electrode lead-out member 22 are covered and filled by the first weld portion 24. Moreover, the second weld portion 2323 in the welded area of ​​the weld zone 2322 and the first electrode lead-out member 22 are fused with the first weld portion 24 to form an integral structure. That is, the second weld portion 2323 in the welded area of ​​the weld zone 2322 and the first electrode lead-out member 22 is embedded in the first weld portion 24.

[0138] It should be noted that the first weld mark portion 24 is a region where the weld mark area 2322 and the first electrode lead-out member 22 are welded to form a mutual fusion or a region where a weld mark is formed by welding.

[0139] In the embodiment of the present application, the first electrode lead-out member 22 serves to electrically connect the first electrode tab 232 of the electrode assembly 23 , serving as an output pole or input pole of the battery cell 20 , thereby being able to output or input electrical energy of the battery cell 20 .

[0140] Among them, the first electrode lead-out member 22 is insulated and installed on the outer shell 21, that is, no electrical connection is formed between the first electrode lead-out member 22 and the outer shell 21. Optionally, the first electrode lead-out member 22 can be arranged on the wall 211 of the outer shell 21, that is, the first electrode lead-out member 22 and the first electrode tab 232 are located at the same end of the main body 231 in the thickness direction X of the wall. Of course, the first electrode lead-out member 22 can also be arranged on other walls of the outer shell 21.

[0141] The first electrode lead-out hole 2111 is provided in the wall portion 211 and is insulated and installed on the wall portion 211. That is, no electrical connection is formed between the first electrode lead-out piece 22 and the wall portion 211 of the outer shell 21. It should be noted that the first electrode lead-out hole 2111 is a structure that penetrates the wall portion 211 along the thickness direction X of the wall portion.

[0142] For example, in the embodiment of the present application, the first electrode lead-out member 22 is an electrode terminal 221 disposed on the wall portion 211. The wall portion 211 is provided with a first electrode lead-out hole 2111. The first electrode lead-out hole 2111 is a structure that penetrates the wall portion 211 along the thickness direction X of the wall portion, and the electrode terminal 221 is disposed within the first electrode lead-out hole 2111 of the wall portion 211 along the thickness direction X of the wall portion. Correspondingly, the electrode terminal 221 is welded to the welded area 2322 to form the first welded portion 24. Of course, in other embodiments, the first electrode lead-out member 22 may also include an electrode terminal 221 and a current collecting member, wherein the electrode terminal 221 is disposed on the housing 21, the current collecting member is welded to the electrode terminal 221, and the current collecting member is welded to the first area 23221 to form the first welded portion 24.

[0143] In some embodiments, see Figure 3 and Figure 4 As shown, the battery cell 20 may further include a second electrode lead-out member 25, which is disposed on the outer shell 21 and is electrically connected to the second electrode tab 233 of the electrode assembly 23, so that the second electrode lead-out member 25 and the first electrode lead-out member 22 can cooperate to input or output electrical energy of the battery cell 20.

[0144] For example, see Figure 4 As shown, the second electrode lead-out member 25 is also arranged on the wall portion 211, and the second electrode lead-out member 25 and the first electrode lead-out member 22 are arranged at intervals. Correspondingly, a second electrode lead-out hole is provided on the wall portion 211, and the second electrode lead-out hole passes through the wall portion 211 along the thickness direction X of the wall portion. The second electrode lead-out member 25 is passed through the second electrode lead-out hole of the wall portion 211 and is insulated and installed on the wall portion 211. That is, no electrical connection is formed between the second electrode lead-out member 25 and the wall portion 211 of the outer shell 21.

[0145] It should be noted that the second pole tab 233 can be a structure identical to that of the first pole tab 232. Similarly, the assembly structure between the second electrode lead-in 25 and the second pole tab 233 can be the same as the assembly structure between the first electrode lead-in 22 and the first pole tab 232. That is, the second pole tab 233 can also be formed with corresponding structures such as a root area 2321 and a weld print area 2322 and a weld print groove 23224 provided on the weld print area 2322. It can also be a structure in which the weld print area 2322 of the second pole tab 233 is located on the inner side of the first area 23221 and is welded to the second electrode lead-in 25.

[0146] In some embodiments, see Figure 3 and Figure 4 As shown, the battery cell 20 may further include a pressure relief component 26 , which is disposed on the housing 21 and is used to release the pressure inside the battery cell 20 when the internal pressure or temperature of the battery cell 20 reaches a predetermined value.

[0147] Exemplarily, the pressure relief component 26 is provided on the end cover 213 of the housing 21. Of course, in other embodiments, the pressure relief component 26 may also be provided on the shell 212 of the housing 21. Similarly, the pressure relief component 26 and the housing 21 may be an integrally formed structure or a separately provided structure. If the pressure relief component 26 and the housing 21 are separately provided structures, the pressure relief component 26 may be connected to the housing 21 by welding or the like. Correspondingly, the pressure relief component 26 may be a component such as an explosion-proof valve, an explosion-proof disk, an air valve, a pressure relief valve, or a safety valve. If the pressure relief component 26 and the housing 21 are an integrally formed structure, the pressure relief component 26 is an area on the housing 21 where a weak structure is formed, for example, an area on the housing 21 where a notch groove is provided.

[0148] In this embodiment, a plurality of weld imprint grooves 23224 are formed on the surface of the weld imprint area 2322 of the first electrode tab 232 in the thickness direction X of the wall portion, and the first area 23221 of the weld imprint area 2322 is a structure interconnected with the root area 2321 of the first electrode tab 232 through the second area 23222, wherein the sum of the areas of all weld imprint grooves 23224 within a unit area of ​​the first area 23221 is set to be greater than the sum of the areas of all weld imprint grooves 23224 within a unit area of ​​the second area 23222, and the first area 23221 of the weld imprint area 2322 is set to connect and surround the first weld imprint portion 23221. 4, so that the first area 23221 of the first electrode tab 232 from the root area 2321 to the weld area 2322 is a structure with an increased density of the weld groove 23224, so that the root area 2321, the second area 23222 and the first area 23221 of the first electrode tab 232 are structures with an increased overall hardness and compaction density, and the first electrode lead-out member 22 is welded to the portion of the weld area 2322 located inside the first area 23221 to form a first weld portion 24. The battery cell 20 with this structure enables the second area 23222 to be connected to the first weld portion 24. A buffer area is formed between the first area 23221 and the root area 2321 to alleviate the phenomenon that the hardness and compaction density of the first pole ear 232 are too large between the position where the first pole ear 232 is connected to the main body 231 and the position where the first electrode lead-out piece 22 is welded. This can reduce the phenomenon that the first pole ear 232 is pulled by the main body 231 or the first electrode lead-out piece 22 during use and the local stress concentration at the edge of the first area 23221 or the first welding portion 24 is reduced, which is beneficial to reducing the risk of local cracking or breaking of the first pole ear 232 during use. On the other hand, it can achieve the first pole ear 232 as the overall hardness and compaction density. The structure in which the area with relatively large solid density is welded and assembled with the first electrode lead-out member 22 can reduce the assembly gap inside the first pole tab 232 and between the first pole tab 232 and the first electrode lead-out member 22, so as to reduce the phenomenon of cold welding or incomplete welding between the first pole tab 232 and the first electrode lead-out member 22, which is beneficial to improving the welding quality and overcurrent effect between the first pole tab 232 and the first electrode lead-out member 22, and thus can effectively reduce the risk of unstable connection or connection failure between the first electrode lead-out member 22 and the electrode assembly 23 during use, so as to improve the stability and service life of the battery cell 20.

[0149] According to some embodiments of the present application, see Figure 7 and Figure 8As shown, the thickness of the portion of the first area 23221 not provided with the weld mark groove 23224 is equal to the thickness of the portion of the second area 23222 not provided with the weld mark groove 23224. In other words, the surface of the first area 23221 provided with the weld mark groove 23224 and the surface of the second area 23222 provided with the weld mark groove 23224 are coplanar, and the surface of the first area 23221 facing away from the weld mark groove 23224 and the surface of the second area 23222 facing away from the weld mark groove 23224 are also coplanar.

[0150] In this embodiment, by setting the thickness of the first area 23221 and the second area 23222 of the weld mark area 2322 in the area where the weld mark groove 23224 is not provided to be the same, the first area 23221 and the second area 23222 of the weld mark area 2322 have a smooth transition structure, which is conducive to improving the overall flatness of the weld mark area 2322 of the first electrode lead 232. On the one hand, it can reduce the difficulty of welding and assembling the weld mark area 2322 and the first electrode lead-out member 22, and is conducive to improving the welding quality between the weld mark area 2322 and the first electrode lead-out member 22. On the other hand, it can alleviate the stress concentration between the first area 23221 and the second area 23222 caused by the different thicknesses of the first area 23221 and the second area 23222 in the area where the weld mark groove 23224 is not provided, which is conducive to reducing the risk of breakage of the first electrode lead 232 during use, thereby improving the stability and service life of the battery cell 20.

[0151] According to some embodiments of the present application, see Figure 6 、 Figure 7 and Figure 8 As shown, the first zone 23221 accounts for 50%-80% of the total area of ​​all welding grooves 23224 within a unit area.

[0152] Among them, the sum of the areas of all welding grooves 23224 within the unit area of ​​the first zone 23221 accounts for 50%-80%, that is, the ratio of the sum of the areas of the notches 23224a of all welding grooves 23224 within the unit area of ​​the first zone 23221 to the unit area is 0.5-0.8.

[0153] Exemplarily, the first zone 23221 may account for 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79% or 80% of the total area of ​​all weld impression grooves 23224 within a unit area.

[0154] In this embodiment, on the one hand, the proportion of the sum of the areas of all the weld grooves 23224 in the first area 23221 of the weld area 2322 is set to be greater than or equal to 50%, which is conducive to increasing the density of the weld grooves 23224 in the first area 23221 of the weld area 2322, so as to improve the overall hardness and compaction density of the first area 23221, thereby facilitating the welding assembly of the weld area 2322 and the first electrode lead-out member 22, and can reduce the phenomenon of false welding or inadequate welding between the weld area 2322 and the first electrode lead-out member 22, thereby improving the weld area 2322 and the first electrode lead-out member 22. The welding quality and overcurrent effect between the first electrode lead-out pieces 22, on the other hand, the proportion of the sum of the areas of all the weld grooves 23224 within the unit area of ​​the first zone 23221 of the weld zone 2322 is set to be less than or equal to 80%, which is conducive to reducing the difficulty of forming the weld grooves 23224 in the first zone 23221, and can reduce the stress concentration phenomenon at the edge of the first zone 23221 during use due to the excessive density of the weld grooves 23224 in the first zone 23221, so as to reduce the risk of cracking or breaking of the first pole ear 232 at the edge of the first zone 23221.

[0155] According to some embodiments of this application, please continue to refer to Figure 6 、 Figure 7 and Figure 8 As shown, the second zone 23222 accounts for 20%-60% of the sum of the areas of all the welding grooves 23224 within the unit area.

[0156] Among them, the sum of the areas of all welding grooves 23224 within the unit area of ​​the second zone 23222 accounts for 20%-60%, that is, the ratio of the sum of the areas of the notches 23224a of all welding grooves 23224 within the unit area of ​​the second zone 23222 to the unit area is 0.2-0.6.

[0157] Exemplarily, the proportion of the sum of the areas of all weld stamps 23224 within a unit area of ​​the second zone 23222 can be 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59% or 60%, etc.

[0158] In this embodiment, on the one hand, the proportion of the second area 23222 of the weld mark area 2322 to the sum of the areas of all the weld mark grooves 23224 within the unit area is set to be greater than or equal to 20%, so that the second area 23222 can play a better buffering role between the root area 2321 where no weld mark grooves 23224 are provided and the first area 23221 with a larger density of weld mark grooves 23224, so as to further reduce the phenomenon of local stress concentration at the edge of the first area 23221 due to the pulling of the main body 231 or the first electrode lead 22 during use of the first electrode ear 232, which is conducive to further reducing the first electrode ear 232 In order to avoid the risk of local cracking or breaking during use, on the other hand, the proportion of the second zone 23222 of the weld zone 2322 to the sum of the areas of all weld grooves 23224 within a unit area is set to be less than or equal to 60%, so that the root zone 2321 and the second zone 23222 can be better connected and transitioned, which is conducive to alleviating the stress concentration between the second zone 23222 and the root zone 2321 caused by the excessive density of the weld grooves 23224 in the second zone 23222, so as to reduce the risk of cracking or breaking at the connection position between the second zone 23222 and the root zone 2321 during use.

[0159] According to some embodiments of the present application, see Figure 6 As shown, the second area 23222 surrounds the outside of the first area 23221. In other words, the second area 23222 is an annular structure disposed around the first area 23221, and the first area 23221 is located inside the second area 23222.

[0160] In this embodiment, the second zone 23222 is set as a structure arranged around the first zone 23221, so that the area with a lower density of the weld mark groove 23224 can better protect the area with a higher density of the weld mark groove 23224. On the one hand, it is convenient for the first zone 23221 to be interconnected with the root zone 2321 through the second zone 23222, which is beneficial to reducing the difficulty of forming the weld mark area 2322 of the first pole ear 232. On the other hand, the second zone 23222 can better play a role in buffering stress between the root zone 2321 and the first zone 23221, which is beneficial to further reduce the risk of cracking or breaking of the first pole ear 232 due to local stress concentration during use.

[0161] According to some embodiments of the present application, Figure 5 、 Figure 6 and Figure 7As shown, the weld print area 2322 is welded to the first electrode lead-out member 22 to form a first weld print portion 24. The weld print area 2322 has a first surface 23225 and a second surface 23226 relative to each other in the thickness direction X of the wall portion. The first surface 23225 is formed with a plurality of weld print grooves 23224. Along the thickness direction X of the wall portion, the second surface 23226 is arranged to face and abut the first electrode lead-out member 22, and the first weld print portion 24 passes through the second surface 23226.

[0162] Among them, the first surface 23225 and the second surface 23226 are the surfaces on both sides of the weld print area 2322 in the thickness direction X of the wall portion. Correspondingly, the first surface 23225 is the surface of the weld print area 2322 provided with the weld print groove 23224, and the second surface 23226 is the surface of the weld print area 2322 in the thickness direction X of the wall portion facing and abutting against the first electrode lead-out member 22.

[0163] The weld print area 2322 is welded to the first electrode lead-out member 22 to form a first weld print portion 24. It should be noted that the first weld print portion 24 is a weld print structure in which the weld print area 2322 is welded to the first electrode lead-out member 22. Part of the first weld print portion 24 is located within the weld print area 2322, and part of the first weld print portion 24 is located within the first electrode lead-out member 22, so that the first weld print portion 24 can connect the weld print area 2322 and the first electrode lead-out member 22. The portion of the first weld print portion 24 located within the weld print area 2322 is directly connected to the first area 23221 and surrounded by the first area 23221. Correspondingly, the first weld print portion 24 passes through the second surface 23226, that is, the second surface 23226 is also welded to the electrode lead-out member. It should be noted that the first weld print portion 24 can be a structure that only passes through the second surface 23226. Of course, the first weld print portion 24 can also be a structure that passes through both the second surface 23226 and the first surface 23225.

[0164] For example, see Figure 5 and Figure 7 As shown, the weld print area 2322 and the first electrode lead-out member 22 are structures in which the weld print area 2322 and the first electrode lead-out member 22 are welded together from a side of the weld print area 2322 facing away from the first electrode lead-out member 22, so that the first weld print portion 24 is a structure that at least partially extends from the first surface 23225 to the inside of the first electrode lead-out member 22, and the first weld print portion 24 is a structure that at least partially extends from the first surface 23225 through the second surface 23226 in the thickness direction X of the wall portion and extends to the inside of the first electrode lead-out member 22.

[0165] Exemplarily, the weld mark area 2322 and the first electrode lead-out member 22 are structures welded by laser.

[0166] In this embodiment, the weld groove 23224 of the weld print area 2322 is provided on the first surface 23225 of the weld print area 2322, the second surface 23226 of the weld print area 2322 is arranged to face and abut the first electrode lead-out member 22, and the first weld portion 24 formed by the weld print area 2322 and the first electrode lead-out member 22 being welded to each other is a structure passing through the second surface 23226, so that the weld print area 2322 is a structure in which the surface on the side where the weld groove 23224 is not provided is welded to the first electrode lead-out member 22, thereby reducing the influence of the weld groove 23224 on the weld connection between the weld print area 2322 and the first electrode lead-out member 22, which is beneficial to reducing the phenomenon of cold welding between the weld print area 2322 and the first electrode lead-out member 22, thereby improving the welding quality between the weld print area 2322 and the first electrode lead-out member 22.

[0167] In some embodiments, see Figure 5 、 Figure 7 and Figure 8 As shown, the second surface 23226 is a plane. In other words, the second surface 23226 of the weld mark area 2322 facing the first electrode lead-out member 22 is a flat and smooth planar structure without obvious pits or protrusions.

[0168] In this embodiment, by setting the second surface 23226 of the weld mark area 2322 facing the first electrode lead-out member 22 to be a flat plane, it is helpful to further reduce the welding gap between the weld mark area 2322 and the first electrode lead-out member 22, thereby further reducing the phenomenon of cold welding between the weld mark area 2322 and the first electrode lead-out member 22, and further improving the welding quality between the weld mark area 2322 and the first electrode lead-out member 22.

[0169] According to some embodiments of the present application, see Figure 6 and Figure 7 As shown, the weld mark area 2322 may further include at least one third area 23223, and the first area 23221 and the second area 23222 are connected via the third area 23223. The sum of the areas of all weld mark grooves 23224 per unit area in the third area 23223 is greater than the sum of the areas of all weld mark grooves 23224 per unit area in the second area 23222, and the sum of the areas of all weld mark grooves 23224 per unit area in the third area 23223 is less than the sum of the areas of all weld mark grooves 23224 per unit area in the first area 23221.

[0170] The third region 23223 is a structure connected between the first region 23221 and the second region 23222 , so that the first region 23221 and the second region 23222 are indirectly connected through the third region 23223 .

[0171] The sum of the areas of all the weld mark grooves 23224 within the unit area of ​​the third zone 23223 is greater than the sum of the areas of all the weld mark grooves 23224 within the unit area of ​​the second zone 23222. That is, in the projection plane perpendicular to the thickness direction X of the wall portion, the sum of the areas of the orthographic projections of the groove wall surfaces of all the weld mark grooves 23224 within the unit area of ​​the third zone 23223 is greater than the sum of the areas of the orthographic projections of the groove wall surfaces of all the weld mark grooves 23224 within the unit area of ​​the second zone 23222. That is, the proportion of the sum of the areas of the orthographic projections of the groove wall surfaces of all the weld mark grooves 23224 within the unit area of ​​the third zone 23223 is greater than that of the second zone 23222. The proportion of the sum of the areas of the orthographic projections of the groove walls of all the weld grooves 23224 in the unit area of ​​zone 23222. Similarly, the sum of the areas of the notches 23224a of all the weld grooves 23224 in the unit area of ​​the third zone 23223 is greater than the sum of the areas of the notches 23224a of all the weld grooves 23224 in the unit area of ​​the second zone 23222, that is, the proportion of the sum of the areas of the notches 23224a of all the weld grooves 23224 in the unit area of ​​the third zone 23223 is greater than the proportion of the sum of the areas of the notches 23224a of all the weld grooves 23224 in the unit area of ​​the second zone 23222.

[0172] The sum of the areas of all the weld grooves 23224 in the third zone 23223 per unit area is smaller than the sum of the areas of all the weld grooves 23224 in the first zone 23221 per unit area. That is to say, in the projection plane perpendicular to the thickness direction X of the wall portion, the sum of the areas of the orthographic projections of the groove wall surfaces of all the weld grooves 23224 in the third zone 23223 per unit area is smaller than the sum of the areas of the orthographic projections of the groove wall surfaces of all the weld grooves 23224 in the first zone 23221 per unit area. That is, the proportion of the sum of the areas of the orthographic projections of the groove wall surfaces of all the weld grooves 23224 in the third zone 23223 per unit area is smaller than that of the first zone 23221. The proportion of the sum of the areas of the orthographic projections of the groove walls of all the weld grooves 23224 in the unit area of ​​zone 23221. Similarly, the sum of the areas of the groove openings 23224a of all the weld grooves 23224 in the unit area of ​​the third zone 23223 is smaller than the sum of the areas of the groove openings 23224a of all the weld grooves 23224 in the unit area of ​​the first zone 23221, that is, the proportion of the sum of the areas of the groove openings 23224a of all the weld grooves 23224 in the unit area of ​​the third zone 23223 is smaller than the proportion of the sum of the areas of the groove openings 23224a of all the weld grooves 23224 in the unit area of ​​the first zone 23221.

[0173] It should be noted that when comparing the sum of the areas of the weld impression grooves 23224 within a unit area of ​​the first area 23221 , the second area 23222 , and the third area 23223 , the units of the unit area are the same.

[0174] In this embodiment, a third area 23223 is further connected between the first area 23221 and the second area 23222 of the weld mark area 2322, and the sum of the areas of all weld mark grooves 23224 per unit area of ​​the third area 23223 is greater than the sum of the areas of all weld mark grooves 23224 per unit area of ​​the second area 23222, and the sum of the areas of all weld mark grooves 23224 per unit area of ​​the third area 23223 is less than the sum of the areas of all weld mark grooves 23224 per unit area of ​​the first area 23221, so that the root area 2321, the second area 23222, the third area 23223 and the first area 232 21 is a structure in which the overall hardness and compaction density increase successively, which is beneficial to further enhance the buffering effect between the root area 2321 and the first area 23221, so as to further alleviate the phenomenon that the hardness and compaction density of the first pole ear 232 are too large between the position where it is connected to the main body 231 and the position where it is welded to the first electrode lead-out piece 22, thereby further reducing the phenomenon that the first pole ear 232 has local stress concentration at the edge of the first area 23221 due to the pulling of the main body 231 or the first electrode lead-out piece 22 during use, which is beneficial to further reduce the risk of local cracking or breakage of the first pole ear 232 during use.

[0175] For example, in Figure 6 In the embodiment, only one third area 23223 is connected between the first area 23221 and the second area 23222. Of course, in some embodiments, the battery cell 20 may also have other structures. For example, the weld mark area 23222 may include multiple third areas 23223. Along the direction from the first area 23221 to the second area 23222, the multiple third areas 23223 are sequentially connected between the first area 23221 and the second area 23222. In each adjacent two third areas 23223, the sum of the areas of all weld mark grooves 23224 per unit area of ​​the third area 23223 close to the first area 23221 is greater than the sum of the areas of all weld mark grooves 23224 per unit area of ​​the third area 23223 close to the second area 23222.

[0176] Among them, along the direction from the first area 23221 to the second area 23222, multiple third areas 23223 are connected in sequence between the first area 23221 and the second area 23222, that is, multiple third areas 23223 are connected between the first area 23221 and the second area 23222, and the multiple third areas 23223 are arranged and connected in sequence between the first area 23221 and the second area 23222 along the direction from the first area 23221 to the second area 23222.

[0177] In each of two adjacent third areas 23223, the sum of the areas of all the weld grooves 23224 per unit area of ​​the third area 23223 close to the first area 23221 is greater than the sum of the areas of all the weld grooves 23224 per unit area of ​​the third area 23223 close to the second area 23222. That is, in each of two adjacent third areas 23223, and in the projection plane perpendicular to the thickness direction X of the wall, the third area 23223 close to the first area 23221 has a unit area of The sum of the areas of the orthographic projections of the groove walls of all the weld imprint grooves 23224 in the third area 23223 far away from the first area 23221 is greater than the sum of the areas of the orthographic projections of the groove walls of all the weld imprint grooves 23224 in the unit area of ​​the third area 23223 far away from the first area 23221, that is, the proportion of the sum of the areas of the orthographic projections of the groove walls of all the weld imprint grooves 23224 in the unit area of ​​the third area 23223 close to the first area 23221 is greater than the proportion of the sum of the areas of the orthographic projections of the groove walls of all the weld imprint grooves 23224 in the unit area of ​​the third area 23223 far away from the first area 23221 4, similarly, the sum of the areas of the notches 23224a of all the weld grooves 23224 within a unit area in the third area 23223 close to the first area 23221 is greater than the sum of the areas of the notches 23224a of all the weld grooves 23224 within a unit area in the third area 23223 far from the first area 23221, that is, the notches 23224a of all the weld grooves 23224 within a unit area in the third area 23223 close to the first area 23221 is greater than the sum of the areas of the notches 23224a of all the weld grooves 23224 within a unit area in the third area 23223 far from the first area 23221. The proportion of the sum of the areas of the notches 23224a is greater than the proportion of the sum of the areas of the notches 23224a of all the weld grooves 23224 within the unit area of ​​the third zone 23223 away from the first zone 23221. Correspondingly, the density of the weld grooves 23224 in the multiple third zones 23223 connected between the first zone 23221 and the second zone 23222 is a structure that decreases successively from the third zone 23223 close to the first zone 23221 to the third zone 23223 close to the second zone 23222.

[0178] In this embodiment, a plurality of third areas 23223 connected in sequence are provided between the first area 23221 and the second area 23222, and in each adjacent two third areas 23223, the sum of the areas of all weld grooves 23224 per unit area of ​​the third area 23223 close to the first area 23221 is greater than the sum of the areas of all weld grooves 23224 per unit area of ​​the third area 23223 close to the second area 23222, so as to realize that the area between the second area 23222 and the first area 23221 is a structure in which the overall hardness and compaction density increase in sequence through the plurality of third areas 23223, thereby further enhancing the buffering effect between the second area 23222 and the first area 23221, and further reducing the phenomenon of local stress concentration at the edge of the first area 23221 of the first electrode tab 232 due to the pulling of the main body 231 or the first electrode lead-out member 22 during use, thereby further reducing the risk of local cracking or breakage of the first electrode tab 232 during use.

[0179] In some embodiments, see Figure 6 As shown, the third area 23223 surrounds the outside of the first area 23221, and the second area 23222 surrounds the outside of the third area 23223. In other words, the second area 23222 and the third area 23223 are both annular structures arranged around the first area 23221, and the first area 23221 is located inside the third area 23223, and the third area 23223 is located inside the second area 23222, making the third area 23223 the outermost annular structure.

[0180] Among them, Figure 6 In the embodiment, the weld imprint area 2322 is provided with only one third area 23223. Correspondingly, the third area 23223 and the second area 23222 are structures that surround the outer side of the first area 23221 in sequence from the inside to the outside. Of course, it should be noted that, in the embodiment where the weld imprint area 2322 includes multiple third areas 23223, the multiple third areas 23223 located between the first area 23221 and the second area 23222 are also structures that surround the outer side of the first area 23221 in sequence from the inside to the outside, and the second area 23222 surrounds the outer sides of the multiple third areas 23223.

[0181] In this embodiment, by setting the third zone 23223 as a structure arranged around the first zone 23221, and setting the second zone 23222 as a structure arranged around the third zone 23223, the second zone 23222, the third zone 23223 and the first zone 23221 are structures arranged around in sequence, so that the area with a lower density of the weld groove 23224 can better protect the area with a higher density of the weld groove 23224, so that the second zone 23222 and the third zone 23223 can better play a role in buffering stress between the first zone 23221 and the root zone 2321, which is beneficial to further reduce the risk of cracking or breaking of the first pole ear 232 due to local stress concentration during use.

[0182] According to some embodiments of the present application, Figure 5 and Figure 6 As shown, the root area 2321 and the weld print area 2322 are arranged along the extension direction of the first electrode tab 232 and are connected.

[0183] Among them, the extension direction of the first pole tab 232 is the direction of the first pole tab 232 extending from one end of the first pole tab 232 connected to the main body 231 to the end away from the main body 231, or from one end of the first pole tab 232 away from the main body 231 to the end connected to the main body 231 along the trajectory of the first pole tab 232 itself.

[0184] The root area 2321 and the weld print area 2322 are arranged and connected along the extension direction of the first electrode tab 232. That is, in the extension direction of the first electrode tab 232, the weld print area 2322 and the main body 231 are arranged at intervals and are not connected, so that the weld print area 2322 is a structure connected to the main body 231 through the root area 2321.

[0185] In this embodiment, by setting the root area 2321 and the weld print area 2322 as a structure arranged along the extension direction of the first pole ear 232, when the main body 231 or the first electrode lead-out part 22 causes pulling on the first pole ear 232 during use, the second area 23222 can play a better buffering role on the root area 2321 and the first area 23221 in the stress transfer path, thereby further reducing the phenomenon of local stress concentration at the edge of the first area 23221 or the first weld print part 24 due to the pulling of the main body 231 or the first electrode lead-out part 22 during use of the first pole ear 232, which is beneficial to further reduce the risk of local cracking or breakage of the first pole ear 232 during use.

[0186] According to some embodiments of the present application, Figure 6 、 Figure 8 and Figure 9As shown, the main body 231 has a straight region 23a, which includes a plurality of first electrode segments 2311a stacked along a first direction Y. A first electrode tab 232 is connected to one end of the first electrode segment 2311a in the wall thickness direction X, which is close to the wall 211. The first electrode tab 232 has two opposing first edges 2324 in the second direction Z. The wall thickness direction X, the first direction Y, and the second direction Z are perpendicular to each other. A second region 23222 is adjacent to the root region 2321, and a plurality of weld marks 23224 in the second region 23222, adjacent to the root region 2321, are arranged along a predetermined trajectory 23227. The predetermined trajectory 23227 includes a straight segment 23227a and two arc segments 23227b. The straight segment 23227a transitions to the two first edges 2324 through the two arc segments 23227b.

[0187] Among them, the straight area 23a also includes a plurality of second pole segments 2312a, the second pole segments 2312a have opposite polarity to the first pole segments 2311a, the first pole segments 2311a and the second pole segments 2312a are alternately and stacked in the first direction Y, and each pole ear piece 232a of the first pole ear 232 is connected to an end of a first pole segment 2311a close to the wall portion 211 in the thickness direction X of the wall portion.

[0188] The first pole tab 232 has two opposite first edges 2324 in the second direction Z, wherein the second direction Z is also the width direction of the first pole tab 232 and also the width direction of each pole tab piece 232a. Correspondingly, the first edge 2324 is also the edge of one side of the second pole tab 233 in its width direction.

[0189] The second area 23222 is adjacent to the root area 2321, and the multiple weld imprint grooves 23224 adjacent to the root area 2321 in the second area 23222 are arranged along the preset trajectory line 23227. That is, the preset trajectory line 23227 is a trajectory line structure formed by sequentially connecting the multiple weld imprint grooves 23224 closest to the root area 2321 among the multiple weld imprint grooves 23224 in the second area 23225 of the first surface 23225 of the weld imprint area 23222.

[0190] The preset trajectory line 23227 includes a straight line segment 23227a and two arc segments 23227b. The straight line segment 23227a transitions to the two first edges 2324 respectively through the two arc segments 23227b. That is, the edge area on one side of the surface of the first pole ear 232 on which the weld groove 23224 is provided is connected to the straight line segment 23227a of the preset trajectory line 23227 through the arc segment 23227b, so that the preset trajectory line 23227 is a structure in which a circular arc transitions to the first edge 2324.

[0191] In the examples of this application, see Figure 6 As shown, the end of the arc segment 23227b connected to the straight segment 23227a is farther away from the main body 231 in the extension direction of the first electrode 232 than the end of the arc segment 23227b connected to the first edge 2324, so that the arc segment 23227b is a structure that bends toward the second area 23222 in the extension direction of the first electrode 232.

[0192] In this embodiment, the plurality of welding grooves 23224 adjacent to the root area 2321 in the second area 23222 are arranged along a preset trajectory line 23227, and the preset trajectory line 23227 includes a straight segment 23227a and two arc segments 23227b. By setting the straight segment 23227a of the preset trajectory line 23227 to be a structure that transitions to the two first edges 2324 of the first tab 232 opposite to each other in the second direction Z through the two arc segments 23227b, the edge of the second area 23222 and the first tab 232 can be realized. The two first edges 2324 that are opposite to each other in the second direction Z are both of an arc transition structure, so as to reduce stress concentration at the connection position between the edge of the second region 23222 and the first edge 2324 during use, thereby alleviating the possibility of tearing of the first tab 232 at the connection position between the edge of the second region 23222 and the first edge 2324, thereby further reducing the risk of unstable connection or connection failure between the first electrode lead-out member 22 and the electrode assembly 23 during use, and further improving the stability and service life of the battery cell 20.

[0193] According to some embodiments of the present application, see Figure 4 、 Figure 5 and Figure 6 As shown, the first electrode lead-out member 22 is an electrode terminal 221 provided on the wall portion 211 , and the electrode terminal 221 is welded to the weld print area 2322 to form a first weld print portion 24 .

[0194] Among them, the first electrode lead-out member 22 is an electrode terminal 221 arranged on the wall portion 211 and passed through the wall portion 211, that is, the first electrode tab 232 and the electrode terminal 221 of the battery cell 20 are directly welded and connected, that is, the first electrode lead-out member 22 only includes the electrode terminal 221, so that the first electrode tab 232 and the electrode terminal 221 are not connected through other components such as the current collecting member. Correspondingly, the battery cell 20 is a structure without an adapter sheet.

[0195] Of course, in other embodiments, the first electrode lead-out member 22 may also be a structure including an electrode terminal 221 and a current collecting member, and the weld print area 2322 of the first electrode tab 232 is welded to the current collecting member, and the current collecting member and the electrode terminal 221 are welded to each other.

[0196] In this embodiment, the first electrode lead-out member 22 is provided with a structure of an electrode terminal 221 mounted on the wall portion 211, and the electrode terminal 221 is directly welded to the weld print area 2322 to achieve electrical connection between the electrode assembly 23 and the first electrode lead-out member 22. The battery cell 20 adopting this structure does not need to further provide a current collecting member or the like in the outer shell 21 for connecting the electrode terminal 221 and the weld print area 2322. On the one hand, the internal space utilization rate of the battery cell 20 can be improved, and the weight of the battery cell 20 can be optimized to increase the energy density of the battery cell 20. On the other hand, the flow path between the electrode assembly 23 and the first electrode lead-out member 22 can be shortened to reduce the internal resistance between the electrode assembly 23 and the first electrode lead-out member 22, thereby improving the flow effect between the electrode assembly 23 and the first electrode lead-out member 22 and improving the performance of the battery cell 20.

[0197] In some embodiments, see Figure 5 and Figure 6 As shown, the weld mark area 2322 and the first electrode lead member 22 are arranged along the thickness direction X of the wall portion, and the weld mark area 2322 is welded to the first electrode lead member 22 to form a first weld mark portion 24. Along the thickness direction X of the wall portion, at least a portion of the first weld mark portion 24 extends from the surface of the weld mark area 2322 on the side facing away from the first electrode lead member 22 into the first electrode lead member 22.

[0198] The weld mark area 2322 and the first electrode lead-out member 22 are arranged along the thickness direction X of the wall portion, and the weld mark area 2322 is located between the first electrode lead-out member 22 and the main body 231 in the thickness direction X of the wall portion.

[0199] Along the thickness direction X of the wall portion, at least a portion of the first weld print portion 24 extends from the surface of the weld print area 2322 on the side facing away from the first electrode lead-out member 22 to the inside of the first electrode lead-out member 22. That is, the welding assembly between the weld print area 2322 and the first electrode lead-out member 22 is a structure in which the weld print area 2322 and the first electrode lead-out member 22 are welded from the side of the weld print area 2322 facing away from the first electrode lead-out member 22, so that the first weld print portion 24 is a structure that at least partially extends from the first surface 23225 to the inside of the weld print area 2322, then passes through the second surface 23226 and extends to the inside of the first electrode lead-out member 22, so that the first weld print portion 24 is connected to both the first surface 23225 and the second surface 23226, and so that in a projection plane perpendicular to the thickness direction X of the wall portion, the orthographic projection of the portion of the first weld print portion 24 located in the electrode lead-out member is located within the orthographic projection of the portion of the first weld print portion 24 located in the weld print area 2322.

[0200] It should be noted that the first weld mark 24 may be a structure that starts from the first surface 23225 and extends into the first electrode lead-out member 22 . Of course, the first weld mark 24 may also be a structure that partially protrudes from the first surface 23225 .

[0201] In this embodiment, the first weld mark portion 24 is a structure that at least partially extends from the surface of the weld mark area 2322 on the side away from the first electrode lead-out member 22 in the thickness direction X of the wall portion to the inside of the first electrode lead-out member 22, so that the welding assembly between the weld mark area 2322 and the first electrode lead-out member 22 is a structure in which welding is performed from the side of the weld mark area 2322 away from the first electrode lead-out member 22. The battery cell 20 with such a structure can reduce the difficulty of assembling the first electrode lead-out member 22 and the first tab 232, and can improve the first electrode lead-out member 22 and the weld mark. The welding quality between the printed areas 2322, on the other hand, facilitates the realization of the structure of the first weld print portion 24 as the weld print area 2322 that welds through the entire first pole tab 232 in the thickness direction X of the wall portion, thereby increasing the flow area between the first pole tab 232 and the first electrode lead-out member 22, so as to improve the flow effect between the first pole tab 232 and the first electrode lead-out member 22, and can alleviate the phenomenon of local welding failure of the first pole tab 232 in the thickness direction X of the wall portion, so as to reduce the risk of unstable connection between the first pole tab 232 and the first electrode lead-out member 22.

[0202] According to some embodiments of the present application, see Figure 4 and Figure 5 As shown, the first electrode lead-out member 22 is disposed on the wall portion 211. The first electrode lead-out member 22 has a connection surface 2211 facing the weld print area 2322 in the wall thickness direction X. The connection surface 2211 abuts against the weld print area 2322 and is welded to the weld print area 2322. In the wall thickness direction X, the root area 2321 extends beyond the connection surface 2211 along the direction from the main body portion 231 to the wall portion 211.

[0203] The connection surface 2211 of the first electrode lead-out member 22 is a surface that is disposed in the thickness direction X of the wall portion and is in contact with the weld print area 2322 of the first electrode tab 232. Correspondingly, the first weld print portion 24 is a structure that partially passes through the connection surface 2211 and extends into the first electrode lead-out member 22. It should be noted that in an embodiment in which at least a portion of the first weld print portion 24 extends from the surface of the weld print area 2322 on a side facing away from the first electrode lead-out member 22 into the first electrode lead-out member 22, the first weld print portion 24 is a structure that at least partially extends from the first surface 23225 into the weld print area 2322, then sequentially passes through the second surface 23226 and the connection surface 2211, and extends into the first electrode lead-out member 22.

[0204] Exemplarily, the weld print area 2322 of the first electrode lead-out member 22 and the first electrode tab 232 is arranged along the thickness direction X of the wall portion, and the weld print area 2322 of the first electrode tab 232 is located at the end of the first electrode lead-out member 22 facing the main body 231 in the thickness direction X of the wall portion. Correspondingly, the connecting surface 2211 is also the surface of the first electrode lead-out member 22 that is closest to and facing the main body 231 in the thickness direction X of the wall portion.

[0205] In the thickness direction X of the wall, the root area 2321 extends beyond the connecting surface 2211 along the direction from the main body 231 to the wall 211, that is, in the thickness direction X of the wall, the surface of the end or one side of the root area 2321 farthest from the main body 231 is farther away from the main body 231 than the connecting surface 2211, that is, the root area 2321 of the first pole ear 232 is a structure partially located on one side of the first electrode lead-out part 22 in a direction perpendicular to the thickness direction X of the wall.

[0206] In this embodiment, the first electrode lead-out member 22 is disposed on the wall portion 211 of the housing 21, and the connection surface 2211 of the first electrode lead-out member 22 facing the weld print area 2322 in the thickness direction X of the wall portion abuts against and is welded to the weld print area 2322. This helps to reduce the difficulty of assembling the first electrode lead-out member 22 and the weld print area 2322, and helps to improve the welding quality between the first electrode lead-out member 22 and the weld print area 2322. Specifically, by configuring the root area 2321 of the first electrode tab 232 to extend beyond the connection surface 2211 in the direction where the main body 231 points to the wall portion 211, the root area 2321 of the first electrode tab 232 can also share space with the first electrode lead-out member 22 in the thickness direction X of the wall portion, thereby improving the internal space utilization of the battery cell 20 and thereby improving the energy density of the battery cell 20.

[0207] According to some embodiments of the present application, see Figure 4 、 Figure 8 and Figure 9 As shown, the electrode assembly 23 can be a laminated structure, and the electrode assembly 23 includes a plurality of first pole pieces 2311 and a plurality of second pole pieces 2312. The polarities of the first pole pieces 2311 and the second pole pieces 2312 are opposite. The first pole pieces 2311 and the second pole pieces 2312 are stacked and alternately arranged along a first direction Y, and the first pole ear 232 is connected to the plurality of first pole pieces 2311. The first direction Y is perpendicular to the thickness direction X of the wall.

[0208] Among them, the first pole ear 232 is connected to multiple first pole pieces 2311, that is, each first pole piece 2311 of the electrode assembly 23 is connected to the first pole ear 232, correspondingly, the first pole ear 232 includes multiple pole ear pieces 232a arranged in a stacked manner, and each pole ear piece 232a of the first pole ear 232 is connected to a first pole piece 2311, and each first pole piece 2311 is connected to a pole ear piece 232a.

[0209] In this embodiment, the electrode assembly 23 is a laminated structure formed by alternating and stacking a plurality of first electrode sheets 2311 and a plurality of second electrode sheets 2312 along a first direction Y. The electrode assembly 23 using this structure can improve the volume energy density of the electrode assembly 23, thereby improving the energy density of the battery cell 20. Specifically, by arranging the first electrode tab 232 so that the first area 23221 from the root area 2321 to the weld area 2322 for connecting with the first weld portion 24 is a structure with increased density of the weld groove 23224, the phenomenon of the first electrode tab 232 being broken or cracked due to local stress concentration during use can be alleviated, thereby effectively alleviating the phenomenon of failure of part of the first electrode sheet 2311 or part of the second electrode sheet 2312 caused by the breakage or cracking of the first electrode tab 232 during use, thereby reducing the risk of a sudden drop in the voltage or energy density of the battery cell 20 during use, thereby improving the performance and stability of the battery cell 20.

[0210] According to some embodiments of the present application, see Figure 7 and Figure 8 As shown, the first electrode tab 232 includes a plurality of electrode tab sheets 232a arranged in a stacked manner, and the plurality of electrode tab sheets 232a are welded to form a plurality of weld grooves 23224 and a second weld portion 2323 is formed at a position corresponding to the weld grooves 23224. The second weld portion 2323 corresponds to the weld grooves 23224 one by one and is located at the bottom of the weld grooves 23224. The second weld portion 2323 only connects the plurality of electrode tab sheets 232a.

[0211] Among them, multiple pole tabs 232a are welded and connected to form multiple weld grooves 23224 and second weld portions 2323 are formed at positions corresponding to the weld grooves 23224. That is, the weld groove 23224 is a groove structure formed by pre-welding of multiple pole tabs 232a of the first pole tab 232, and multiple pole tabs 232a are welded and connected to form multiple second weld portions 2323. Correspondingly, each second weld portion 2323 is located at the bottom of a weld groove 23224, that is, at least part of each second weld portion 2323 forms at least part of the bottom wall of a weld groove 23224, so that the weld groove 23224 and the second weld portion 2323 are structures arranged one by one in the thickness direction X of the wall.

[0212] The second weld mark 2323 is only connected to the multiple electrode tabs 232a, that is, the second weld mark 2323 is a structure that is only connected to the multiple electrode tabs 232a of the first electrode tab 232, and the second weld mark 2323 is not connected to other components, so that the second weld mark 2323 is a structure that is entirely located in the weld mark area 2322 of the second electrode tab 233. Of course, the second weld mark 2323 can also be a surface that partially protrudes from the side of the weld mark area 2322 away from the weld mark groove 23224, that is, the second weld mark 2323 can be a structure that is mostly located in the weld mark area 2322 of the second electrode tab 233 but partially protrudes from the second surface 23226 of the weld mark area 2322.

[0213] In this embodiment, the plurality of pole tabs 232a of the first pole tab 232 are welded and connected to form a plurality of weld grooves 23224, and second weld portions 2323 are formed at positions corresponding to the weld grooves 23224, and the second weld portions 2323 are only connected to the plurality of pole tabs 232a, so that the weld grooves 23224 on the first pole tab 232 are a structure formed by welding the plurality of pole tabs 232a stacked on the first pole tab 232, and the second weld portion 2323 corresponding to the bottom of each weld groove 23224 is a structure formed by pre-welding the plurality of pole tabs 232a. The battery cell 20 adopting this structure can realize pre-welding and fixing the plurality of pole tabs 232a of the first pole tab 232 before assembling the first pole tab 232 and the first electrode lead-out member 22. On the one hand, it can reduce the phenomenon of movement or displacement of the plurality of pole tabs 232a of the first pole tab 232 during the process of welding and assembling with the first electrode lead-out member 22, thereby reducing the first pole tab 232 and the first electrode lead-out member 22 from being moved or shifted. The phenomenon of cold welding or partial electrode tab 232a not being welded in place occurs between the electrode lead-out parts 22, so as to improve the assembly quality and overcurrent effect between the first electrode tab 232 and the first electrode lead-out part 22. On the other hand, since the sum of the areas of all weld imprint grooves 23224 within a unit area of ​​the first area 23221 is set to be greater than the sum of the areas of all weld imprint grooves 23224 within a unit area of ​​the second area 23222, and the first area 23221 is connected to and arranged around the first weld imprint 24, the second area 23222 can also play a role in buffering stress during the mutual welding and assembly of the weld imprint area 2322 and the first electrode lead-out part 22, so as to reduce the risk of stress concentration at the edge of the first area 23221 causing cracking or breaking of part of the electrode tab 232a, thereby further reducing the risk of unstable connection or connection failure between the first electrode lead-out part 22 and the electrode assembly 23 during use, so as to further improve the stability and service life of the battery cell 20.

[0214] According to some embodiments of the present application, the present application further provides a battery device 100 , which includes a battery cell 20 according to any of the above solutions.

[0215] Among them, see Figure 2 As shown, the battery device 100 may further include a box body 10 , in which the battery cells 20 are accommodated.

[0216] In some embodiments, the box body 10 may include a first box body 11 and a second box body 12 . The first box body 11 and the second box body 12 cover each other, and the first box body 11 and the second box body 12 jointly define an assembly space for accommodating the battery cells 20 .

[0217] 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, and 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 jointly define an 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.

[0218] Of course, the box body 10 formed by the first box body 11 and the second box body 12 can be in various shapes, such as a cylinder or a rectangular parallelepiped. Figure 2 In the embodiment, the box body 10 is a rectangular parallelepiped structure.

[0219] Optionally, the number of battery cells 20 disposed in the box body 10 may be one or more. Figure 2 In the embodiment, a battery device 100 is provided with a plurality of battery cells 20 within the housing 10. The plurality of battery cells 20 may be connected in series, in parallel, or in a hybrid configuration. A hybrid configuration refers to a configuration in which the plurality of battery cells 20 are connected both in series and in parallel. The plurality of battery cells 20 may be directly connected in series, in parallel, or in a hybrid configuration, and then the entire battery device 20 is housed within the housing 10. Alternatively, the battery device 100 may be formed by first connecting the plurality of battery cells 20 in series, in parallel, or in a hybrid configuration to form a battery module, and then the plurality of battery modules are further connected in series, in parallel, or in a hybrid configuration to form an entire battery device, which is then housed within the housing 10.

[0220] The battery device 100 may further include other structures. For example, the battery device 100 may further include a busbar component, which connects the plurality of battery cells 20 to achieve electrical connection between the plurality of battery cells 20 .

[0221] It should be noted that, in some embodiments, the battery device 100 may not be provided with a housing 10. The battery device 100 includes a plurality of battery cells 20. The battery device 100 composed of a plurality of battery cells 20 can be directly assembled on an electrical device to provide electrical energy to the electrical device through the plurality of battery cells 20. In other words, the housing 10 can serve as part of the electrical device. Taking the vehicle 1000 as an example of the electrical device, the housing 10 can serve as part of the chassis structure of the vehicle 1000. For example, a portion of the housing 10 can become at least a portion of the floor of the vehicle 1000, or a portion of the housing 10 can become at least a portion of the crossbeam and longitudinal beam of the vehicle 1000.

[0222] According to some embodiments of the present application, the present application further provides an electrical device, which includes the battery cell 20 of any of the above solutions, and the battery cell 20 is used to provide electrical energy to the electrical device.

[0223] The electrical device may be any of the aforementioned devices or systems using the battery cell 20 .

[0224] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0225] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A battery cell, characterized in that: include: a housing having a wall portion; A first electrode lead-out member is provided on the housing; as well as at least one electrode assembly disposed in the housing, the electrode assembly comprising a main body and a first electrode tab connected to an end of the main body facing the wall; The first tab includes a root area and a weld print area that are connected to each other, the root area is connected to the main body, the weld print area includes a first area and a second area, the first area is connected to the root area through the second area, and the weld print area is formed with a plurality of weld print grooves on a surface on one side in the thickness direction of the wall portion, the sum of the areas of all the weld print grooves per unit area in the first area is greater than the sum of the areas of all the weld print grooves per unit area in the second area, the weld print area is welded to the first electrode lead-out piece to form a first weld print portion, and the first area is connected to and surrounds the outside of the first weld print portion.

2. The battery cell according to claim 1, wherein: The thickness of the portion of the first area where the weld mark groove is not provided is equal to the thickness of the portion of the second area where the weld mark groove is not provided.

3. The battery cell according to claim 1, wherein: The first zone accounts for 50%-80% of the total area of ​​all the weld impression grooves within a unit area.

4. The battery cell according to claim 1, wherein: The second zone accounts for 20%-60% of the sum of the areas of all the weld impression grooves within a unit area.

5. The battery cell according to claim 1, characterized in that The second area surrounds the outer side of the first area.

6. The battery cell according to claim 1, characterized in that The weld print area has a first surface and a second surface opposite to each other in the thickness direction of the wall portion, the first surface is formed with a plurality of weld print grooves, the second surface is arranged facing and abutting against the first electrode lead-out piece along the thickness direction of the wall portion, and the first weld print portion passes through the second surface.

7. The battery cell according to claim 6, characterized in that The second surface is a plane.

8. The battery cell according to any one of claims 1 to 7, characterized in that: The welding area further includes at least one third area, and the first area and the second area are connected through the third area; The sum of the areas of all the weld imprint grooves in the third zone per unit area is greater than the sum of the areas of all the weld imprint grooves in the second zone per unit area, and the sum of the areas of all the weld imprint grooves in the third zone per unit area is less than the sum of the areas of all the weld imprint grooves in the first zone per unit area.

9. The battery cell according to claim 8, characterized in that The weld print area includes a plurality of third areas, and the plurality of third areas are sequentially connected between the first area and the second area along the direction from the first area to the second area; In each of two adjacent third areas, the sum of the areas of all the weld imprint grooves within a unit area of ​​the third area close to the first area is greater than the sum of the areas of all the weld imprint grooves within a unit area of ​​the third area close to the second area.

10. The battery cell according to claim 8, characterized in that The third region surrounds the outer side of the first region, and the second region surrounds the outer side of the third region.

11. The battery cell according to any one of claims 1 to 7, characterized in that: The root area and the weld print area are arranged and connected along the extension direction of the first electrode tab.

12. The battery cell according to claim 11, characterized in that The main body has a straight region, the straight region includes a plurality of first electrode segments stacked along a first direction, the first electrode tab is connected to one end of the first electrode segment close to the wall in the thickness direction of the wall, the first electrode tab has two opposing first edges in a second direction, and the thickness direction of the wall, the first direction, and the second direction are perpendicular to each other; The second area is adjacent to the root area, and the plurality of weld impression grooves adjacent to the root area in the second area are arranged along a preset trajectory line, the preset trajectory line includes a straight line segment and two arc segments, and the straight line segment transitions to the two first edges respectively through the two arc segments.

13. The battery cell according to any one of claims 1 to 7, characterized in that: The first electrode lead-out member is an electrode terminal provided on the wall portion, and the electrode terminal is welded to the weld print area to form the first weld print portion.

14. The battery cell according to claim 13, characterized in that The weld print area and the first electrode lead-out member are arranged along the thickness direction of the wall portion; Wherein, along the thickness direction of the wall portion, at least a portion of the first weld print portion extends from a surface of the weld print area on a side away from the first electrode lead-out member into the first electrode lead-out member.

15. The battery cell according to any one of claims 1 to 7, characterized in that: The first electrode lead-out member is provided on the wall portion, and the first electrode lead-out member has a connection surface facing the weld print area in the thickness direction of the wall portion, the connection surface abuts against the weld print area and is welded to the weld print area; Wherein, in the thickness direction of the wall portion, the root region extends beyond the connecting surface along a direction from the main body portion to the wall portion.

16. The battery cell according to any one of claims 1 to 7, characterized in that: The electrode assembly is a laminated structure, comprising a plurality of first pole pieces and a plurality of second pole pieces, wherein the polarities of the first pole pieces and the second pole pieces are opposite, the first pole pieces and the second pole pieces are stacked and alternately arranged along a first direction, and the first pole ear is connected to the plurality of first pole pieces, and the first direction is perpendicular to the thickness direction of the wall portion.

17. The battery cell according to any one of claims 1 to 7, characterized in that: The first electrode tab includes a plurality of electrode tab sheets stacked together, the plurality of electrode tab sheets are welded to form a plurality of weld imprint grooves and a second weld imprint portion is formed at a position corresponding to the weld imprint groove. The second weld imprint portion corresponds one-to-one to the weld imprint groove and is located at the bottom of the weld imprint groove. The second weld imprint portion only connects the plurality of electrode tab sheets.

18. A battery device, characterized in that: The invention comprises the battery cell according to any one of claims 1 to 17.

19. An electrical device, characterized in that: The battery cell comprises the battery cell according to any one of claims 1 to 17, wherein the battery cell is used to provide electrical energy.

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