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

[0001] This application is a divisional application based on the invention with application number 202511196201.8, application date August 26, 2025, entitled "Battery cell, battery device and power consumption device". Technical Field

[0002] This application relates to the field of battery technology, and more specifically, to a battery cell, a battery device, and an electrical device. Background Technology

[0003] In recent years, new energy vehicles have experienced rapid development. In the field of electric vehicles, power batteries, as the power source, play an irreplaceable and crucial role. With the vigorous promotion of new energy vehicles, the demand for power battery products is also increasing day by day.

[0004] In battery technology, a battery device includes a housing and battery cells housed within the housing. Each battery cell includes a casing and electrode assemblies housed within the casing. Correspondingly, the casing is also provided with electrode terminals. By electrically connecting the electrode terminals to the tabs of the electrode assemblies, the battery cell can input or output electrical energy through the electrode terminals. However, existing battery cells are prone to tab cracking or even breakage during use, which can lead to unstable connections or connection failures between the electrode terminals and electrode assemblies during use, thus hindering the improvement of the battery cell's stability and lifespan. Summary of the Invention

[0005] This application provides a battery cell, a battery device, and an electrical device, which can effectively improve the stability and service life of the battery cell.

[0006] In a first aspect, embodiments of this application provide a battery cell, including a casing, a first electrode lead, and at least one electrode assembly; the casing has a wall portion; the first electrode lead is disposed in the casing; the electrode assembly is disposed within the casing, the electrode assembly including 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 includes a root region and a soldering region interconnected, the root region being connected to the main body portion, the soldering region including a first region and a second region, the first region being connected to the root region through the second region, the soldering region having a plurality of solder grooves formed on the surface of one side of the wall portion in the thickness direction, the sum of the areas of all the solder grooves in the first region per unit area being greater than the sum of the areas of all the solder grooves in the second region per unit area, the soldering region being connected to the first electrode lead, the first electrode lead being disposed in the casing ... An electrode lead is welded to form a first solder mark, and the first region is connected to and surrounds the outside of the first solder mark; the root region and the solder mark region are arranged and connected along the extension direction of the first electrode tab; the main body has a flat region, the flat 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 near the wall in the thickness direction of the wall; and the first electrode tab has two opposing first edges in a second direction; the thickness direction of the wall, the first direction, and the second direction are perpendicular to each other; the second region is adjacent to the root region; and a plurality of solder grooves adjacent to the root region in the second region are arranged along a preset trajectory line; the preset trajectory line includes a straight segment and two arc segments; the straight segment transitions to the two first edges through the two arc segments respectively.

[0007] In the above technical solution, the soldering area of ​​the first electrode tab has multiple solder grooves formed on one side of the wall thickness direction. The first region of the soldering area is interconnected with the root region of the first electrode tab through the second region. By setting the sum of the areas of all solder grooves in the first region per unit area to be greater than the sum of the areas of all solder grooves in the second region per unit area, and by setting the first region of the soldering area to connect with and surround the first soldering portion, the density of solder grooves in the first region of the first electrode tab increases from the root region to the first region of the soldering area. This achieves a structure where the root region, the second region, and the first region of the first electrode tab have progressively increasing overall hardness and compaction density. Furthermore, the first electrode lead is welded to the portion of the soldering area located inside the first region to form the first soldering portion. This battery cell structure allows the second region to form a buffer area between the first region connected to the first soldering portion and the root region, thus alleviating the pressure on the first electrode tab from the connection with the main body. The large difference in hardness and compaction density between the location of the first tab and the location where it is welded to the first electrode lead reduces the occurrence of local stress concentration at the edge of the first area or the first weld mark due to the pulling of the main body or the first electrode lead during use. This helps reduce the risk of local cracking or breakage of the first tab during use. On the other hand, it enables the first tab to be welded to the first electrode lead in a structure where the area with relatively high overall hardness and compaction density is integrated. This reduces the assembly gap inside the first tab and between the first tab and the first electrode lead, thus reducing the occurrence of incomplete or faulty welds. This improves the welding quality and current flow effect between the first tab and the first electrode lead, and effectively reduces the risk of unstable or failed connections between the first electrode lead and the electrode assembly during use, thereby improving the stability and service life of the battery cell.Furthermore, by arranging the root region and solder area along the extension direction of the first tab, the second region can effectively buffer the root region and the first region when the main body or the first electrode lead-out pulls on the first tab during use. Additionally, the multiple solder grooves adjacent to the root region within the second region are arranged along a preset trajectory line, which includes a straight segment and two curved segments. By setting the straight segment of the preset trajectory line to transition to the two opposite first edges of the first tab in the second direction via two curved segments, both the edges of the second region and the two opposite first edges of the first tab in the second direction are rounded transitions. This reduces stress concentration at the connection point between the edges of the second region and the first edges during use, thereby mitigating tearing at the connection point of the first tab between the edges of the second region and the first edges. This further reduces the risk of unstable or failed connections for the first electrode lead-out and electrode assembly during use, thus improving the stability and lifespan of the battery cell.

[0008] In some embodiments, the thickness of the portion of the first region where the solder groove is not provided is equal to the thickness of the portion of the second region where the solder groove is not provided.

[0009] In the above technical solution, by setting the thickness of the first and second areas of the soldering area to be the same, the first and second areas of the soldering area have a smooth transition structure, which helps to improve the overall flatness of the soldering area of ​​the first electrode tab. On the one hand, it can reduce the difficulty of welding and assembling the soldering area with the first electrode lead and improve the welding quality between the soldering area and the first electrode lead. On the other hand, it can alleviate the stress concentration phenomenon between the first and second areas caused by the difference in thickness in the areas without soldering grooves, which helps to reduce the risk of breakage of the first electrode tab during use, thereby improving the stability and service life of the battery cell.

[0010] In some embodiments, the first region accounts for 50%-80% of the sum of the areas of all the solder grooves per unit area.

[0011] In the above technical solution, on the one hand, setting the proportion of the sum of the areas of all solder grooves in the first area of ​​the soldering area to be greater than or equal to 50% is beneficial to increasing the density of solder grooves in the first area of ​​the soldering area, thereby improving the overall hardness and compaction density of the first area. This facilitates the welding and assembly of the soldering area and the first electrode lead, and reduces the occurrence of incomplete welding or welding between the soldering area and the first electrode lead, thus improving the welding quality and current flow effect between the soldering area and the first electrode lead. On the other hand, setting the proportion of the sum of the areas of all solder grooves in the first area of ​​the soldering area to be less than or equal to 80% is beneficial to reducing the difficulty of forming solder grooves in the first area, and can reduce the stress concentration phenomenon at the edge of the first area during use caused by excessive density of solder grooves in the first area, thereby reducing the risk of cracking or breakage of the first electrode tab at the edge of the first area.

[0012] In some embodiments, the second region accounts for 20%-60% of the sum of the areas of all the solder grooves per unit area.

[0013] In the above technical solution, on the one hand, the proportion of the sum of the areas of all solder grooves in the second zone of the soldering area per 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 without solder grooves and the first zone with a larger solder groove density, thereby further reducing 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, which is conducive to further reducing the risk of local cracking or breakage of the first electrode during use. On the other hand, the proportion of the sum of the areas of all solder grooves in the second zone of the soldering area per 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 conducive to alleviating the phenomenon of stress concentration between the second zone and the root zone caused by the excessive density of solder grooves in the second zone, thereby reducing the risk of cracking or breakage at the connection position between the second zone and the root zone during use.

[0014] In some embodiments, the second region surrounds the outside of the first region.

[0015] In the above technical solution, by setting the second region as a structure surrounding the first region, the area with lower density of the solder groove can better protect the area with higher density of the solder groove. This facilitates the connection between the first region and the root region through the second region, which helps reduce the forming difficulty of the solder area of ​​the first electrode tab. On the other hand, the second region can better buffer stress between the root region and the first region, which helps to further reduce the risk of cracking or breakage of the first electrode tab due to local stress concentration during use.

[0016] In some embodiments, the solder area has opposing first and second surfaces in the thickness direction of the wall portion, the first surface having a plurality of solder grooves formed thereon, the second surface facing and abutting the first electrode lead along the thickness direction of the wall portion, and the first solder portion passing through the second surface.

[0017] In the above technical solution, the solder groove of the soldering area is provided on the first surface of the soldering area, the second surface of the soldering area faces and abuts against the first electrode lead, and the first solder part formed by the soldering connection between the soldering area and the first electrode lead is a structure that passes through the second surface. This makes the soldering area a structure in which the surface without the solder groove is welded to the first electrode lead, thereby reducing the influence of the solder groove on the welding connection between the soldering area and the first electrode lead, which is beneficial to reducing the phenomenon of incomplete soldering between the soldering area and the first electrode lead, and thus improving the welding quality between the soldering area and the first electrode lead.

[0018] In some embodiments, the second surface is a plane.

[0019] In the above technical solution, by setting the second surface of the solder area facing the first electrode lead as a flat plane, it is beneficial to further reduce the welding gap between the solder area and the first electrode lead, thereby further reducing the phenomenon of incomplete soldering between the solder area and the first electrode lead, so as to further improve the welding quality between the solder area and the first electrode lead.

[0020] In some embodiments, the solder area further includes at least one third area, wherein the first area and the second area are connected through the third area; wherein the sum of the areas of all solder grooves in the third area per unit area is greater than the sum of the areas of all solder grooves in the second area per unit area, and the sum of the areas of all solder grooves in the third area per unit area is less than the sum of the areas of all solder grooves in the first area per unit area.

[0021] In the above technical solution, a third zone is connected between the first and second zones of the soldering area. The sum of the areas of all soldering grooves in the third zone per unit area is greater than the sum of the areas of all soldering grooves in the second zone per unit area, while the sum of the areas of all soldering grooves in the third zone per unit area is less than the sum of the areas of all soldering grooves in the first zone per unit area. This makes the root zone, the second zone, the third zone, and the first zone of the first electrode tab a structure with progressively increasing overall hardness and compaction density. This is beneficial to further improve the buffering effect between the root zone and the first zone, thereby further alleviating the phenomenon of excessively large spans in hardness and compaction density between the first electrode tab and the position where it is connected to the main body and the position where it is welded to the first electrode lead. This can 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, and further reduce the risk of local cracking or breakage of the first electrode tab during use.

[0022] In some embodiments, the solder area includes a plurality of third areas, which are sequentially connected between the first area and the second area along the direction from the first area to the second area; wherein, in every two adjacent third areas, the sum of the areas of all solder grooves in a unit area of ​​the third area closer to the first area is greater than the sum of the areas of all solder grooves in a unit area of ​​the third area closer to the second area.

[0023] In the above technical solution, by setting multiple third zones connected sequentially between the first zone and the second zone, and in each pair of adjacent third zones, the sum of the areas of all solder grooves in the third zone closer to the first zone within a unit area is greater than the sum of the areas of all solder grooves in the third zone closer to the second zone within a unit area, the area between the second zone and the first zone is structured so that the overall hardness and compaction density increase sequentially through multiple third zones. This can further improve the buffering effect between the second zone and the first zone, and help 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. In this way, the risk of local cracking or breakage of the first electrode during use can be further reduced.

[0024] In some embodiments, the third region surrounds the outside of the first region, and the second region surrounds the outside of the third region.

[0025] In the above technical solution, by setting the third region to surround the first region and setting the second region to surround the third region, the second region, the third region and the first region are arranged in a sequentially surrounding structure. This allows the area with lower density of the solder groove to better protect the area with higher density of the solder groove. As a result, the second region and the third region can better buffer stress between the first region and the root region, which is beneficial to further reduce the risk of cracking or breakage of the first electrode tab due to local stress concentration during use.

[0026] In some embodiments, the first electrode lead is an electrode terminal disposed on the wall portion, and the electrode terminal is welded to the solder area to form the first solder area.

[0027] In the above technical solution, by setting the first electrode lead as an electrode terminal mounted on the wall and directly welding the electrode terminal to the solder area, the electrical connection between the electrode assembly and the first electrode lead is realized. The battery cell with this structure does not need to further set current collectors or other structures for connecting the electrode terminals and the solder area inside the casing. On the one hand, it can improve the internal space utilization 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 current path between the electrode assembly and the first electrode lead to reduce the internal resistance between the electrode assembly and the first electrode lead, thereby improving the current flow effect between the electrode assembly and the first electrode lead and improving the performance of the battery cell.

[0028] In some embodiments, the solder area and the first electrode lead 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 solder area extends from the surface of the solder area on the side opposite to the first electrode lead into the first electrode lead.

[0029] In the above technical solution, the first solder mark is a structure in which at least part of the solder mark extends from the surface of the solder mark area away from the first electrode lead into the first electrode lead in the thickness direction of the wall portion. This makes the welding assembly between the solder mark area and the first electrode lead a structure in which welding is performed from the side of the solder mark area away from the first electrode lead. The battery cell with this structure can reduce the assembly difficulty between the first electrode lead and the first tab and improve the welding quality between the first electrode lead and the solder mark area. On the other hand, it is easy to realize that the first solder mark is a structure in which the solder mark area is welded through the entire first tab in the thickness direction of the wall portion. This can increase the flow area between the first tab and the first electrode lead to improve the flow effect between the first tab and the first electrode lead. It can also alleviate the phenomenon of local welding incompleteness in the thickness direction of the wall portion of the first tab, thereby reducing the risk of unstable connection between the first tab and the first electrode lead.

[0030] In some embodiments, the first electrode lead is disposed on the wall portion, and the first electrode lead has a connecting surface facing the solder area in the thickness direction of the wall portion, the connecting surface abutting against the solder area and being welded to the solder area; wherein, in the thickness direction of the wall portion, the root region extends beyond the connecting surface in the direction from the main body portion toward the wall portion.

[0031] In the above technical solution, the first electrode lead is disposed on the wall of the outer casing, and the connecting surface of the first electrode lead facing the solder area in the thickness direction of the wall abuts against and is welded to the solder area. This helps to reduce the assembly difficulty between the first electrode lead and the solder area and improves the welding quality between the first electrode lead and the solder area. In particular, by setting the root area of ​​the first tab to extend beyond the connecting surface in the direction of the main body pointing towards the wall, the root area of ​​the first tab can also share space with the first electrode lead in the thickness direction of the wall, thereby improving the internal space utilization of the battery cell and increasing the energy density of the battery cell.

[0032] In some embodiments, the electrode assembly is a stacked structure, the electrode assembly includes a plurality of first electrodes and a plurality of second electrodes, the first electrodes and the second electrodes have opposite polarities, the first electrodes and the second electrodes are stacked and alternately arranged along a first direction, and the first electrode tab is connected to the plurality of first electrodes, the first direction being perpendicular to the thickness direction of the wall portion.

[0033] In the above technical solution, the electrode assembly is a stacked structure formed by alternating and stacking multiple first electrode sheets and multiple second electrode sheets along a first direction. The electrode assembly with this structure can improve the volumetric energy density of the electrode assembly, thereby improving the energy density of the battery cell. In particular, by setting the first tab to be a structure with increased density of the first area from the root region to the soldering area for connection with the first soldering part, the phenomenon of breakage or cracking of the first tab due to local stress concentration during use can be alleviated. This can effectively mitigate the phenomenon of failure of some first electrode sheets or some second electrode sheets caused by breakage or cracking of the first tab during use, thereby reducing the risk of sudden drop in voltage or energy density of the battery cell during use, and improving the performance and stability of the battery cell.

[0034] In some embodiments, the first electrode tab includes a plurality of electrode tab pieces stacked together, the plurality of electrode tab pieces are welded together to form a plurality of solder grooves and a second solder part is formed at the position corresponding to the solder grooves, the second solder part corresponds one-to-one with the solder grooves and is located at the bottom of the solder grooves, and the second solder part is connected only to the plurality of electrode tab pieces.

[0035] In the above technical solution, multiple tabs of the first electrode are welded together to form multiple solder grooves, and a second solder part is formed at the corresponding position of the solder groove. The second solder part only connects multiple tabs, so that the solder groove on the first electrode is a structure formed by welding multiple tabs stacked on the first electrode together, and the second solder part corresponding to the bottom of each solder groove is a structure formed by pre-welding multiple tabs. The battery cell with this structure can realize the pre-welding and fixing of multiple tabs of the first electrode before assembling the first electrode and the first electrode lead. On the one hand, it can reduce the phenomenon of multiple tabs of the first electrode moving or shifting during the welding and assembly process with the first electrode lead, thereby reducing the occurrence of problems between the first electrode and the first electrode lead. To address issues such as incomplete soldering or improper welding of the tabs, the assembly quality and current-carrying effect between the first tab and the first electrode lead are improved. Furthermore, since the sum of the areas of all solder grooves in the first region per unit area is set to be greater than the sum of the areas of all solder grooves in the second region per unit area, and the first region connects to and surrounds the first solder section, the second region can also buffer stress during the welding and assembly process between the solder area and the first electrode lead. This reduces the risk of stress concentration at the edges of the first region, which could cause cracking or breakage of some tabs. Consequently, it further reduces the risk of unstable or failed connections between the first electrode lead and the electrode assembly during use, thereby further improving the stability and lifespan of the battery cell.

[0036] Secondly, embodiments of this application also provide a battery device, including the aforementioned battery cell.

[0037] Thirdly, embodiments of this application also provide an electrical device, including the aforementioned battery cell, wherein the battery cell is used to provide electrical energy. Attached Figure Description

[0038] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments; Figure 2 Exploded views of the structure of the battery device provided in some embodiments of this application; Figure 3 This is a schematic diagram of the structure of a battery cell provided in some embodiments of this application; Figure 4 Exploded views of the structure of a single battery cell provided in some embodiments of this application; Figure 5 Partial cross-sectional view of a battery cell provided in some embodiments of this application; Figure 6 This is a schematic diagram of the assembly of the electrode lead-out and the first electrode tab provided in some embodiments of this application; Figure 7 Partial cross-sectional view of the electrode lead-out and the first electrode tab after assembly, provided in some embodiments of this application; Figure 8 for Figure 7 A magnified view of point A of the first electrode tab shown; Figure 9 A cross-sectional view of the main body of an electrode assembly provided in some embodiments of this application, perpendicular to the thickness direction of the wall portion; Figure 10 A cross-sectional view of the main body of an electrode assembly provided in some embodiments of this application, perpendicular to the thickness direction of the wall portion.

[0040] Icons: 1000 - Vehicle; 100 - Battery assembly; 10 - Housing; 11 - First housing body; 12 - Second housing body; 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 piece; 221 - Electrode terminal; 2211 - Connecting surface; 23 - Electrode assembly; 23a - Straight area; 23b - Bending area; 231 - Main body; 2311 - First electrode plate; 2311a - First electrode segment; 2311b - First bending segment; 2312 - Second electrode plate; 2312a - Second electrode segment; 2312b - Second bending segment; 2313 - Separator; 232 - First tab; 232a-tab piece; 2321-root area; 2322-soldering area; 23221-first zone; 23222-second zone; 23223-third zone; 23224-soldering groove; 23224a-groove opening; 23225-first surface; 23226-second surface; 23227-preset trajectory line; 23227a-straight line segment; 23227b-arc segment; 2323-second soldering part; 2324-first edge; 233-second tab; 24-first soldering part; 25-second electrode lead-out; 26-pressure relief component; 200-controller; 300-motor; X-thickness direction of the wall; Y-first direction; Z-second direction; R-winding direction. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0042] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0043] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0044] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0045] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0046] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0047] In this application, "multiple" means two or more (including two).

[0048] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0049] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0050] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, serves to prevent short circuits to some extent while allowing active ions to pass through.

[0051] 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.

[0052] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0053] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, or titanium, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0054] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium phosphate include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4 (also referred to as LFP)), lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO4), lithium manganese phosphate and carbon composites, lithium iron manganese phosphate, and lithium iron manganese phosphate and carbon composites. Examples of lithium transition metal oxides include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, and lithium nickel cobalt manganese oxide (such as LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (also known as NCM) 333 LiNi 0.5 Co 0.2 Mn 0.3 O2 (also known as NCM) 523 LiNi 0.5 Co 0.25 Mn 0.25 O2 (also known as NCM) 211 LiNi 0.6 Co 0.2 Mn 0.2 O2 (also known as NCM)622 LiNi 0.8 Co 0.1 Mn 0.1 O2 (also known as NCM) 811 ), lithium nickel cobalt aluminum oxide (such as LiNi) 0.85 Co 0.15 Al 0.05 At least one of O2 and its modified compounds.

[0055] In some embodiments, the positive electrode can be a foamed metal. The foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloys, etc. When foamed metal is used as the positive electrode, the surface of the foamed metal may or may not contain a positive electrode active material. As an example, lithium source material, potassium metal, or sodium metal can also be filled and / or deposited within the foamed metal, where the lithium source material is lithium metal and / or a lithium-rich material.

[0056] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0057] As an example, the negative electrode current collector can be a metal foil, a foamed metal, or a composite current collector. For example, as a metal foil, it can be silver-treated aluminum or stainless steel, stainless steel, copper, aluminum, nickel, carbon electrodes, or titanium, etc. Foamed metal can be foamed nickel, foamed copper, foamed aluminum, foamed alloys, etc. Composite current collectors can include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming a metal material (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0058] 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.

[0059] As an example, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0060] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as battery negative electrode active materials may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0061] In some embodiments, the positive current collector can be made of aluminum, and the negative current collector can be made of copper.

[0062] In some embodiments, the electrode assembly further includes an isolator disposed between the positive and negative electrodes.

[0063] In some embodiments, the separator is a separator membrane. The separator membrane can be of various types, and any known porous separator membrane with good chemical and mechanical stability can be selected.

[0064] As an example, the material of the separator may include at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multi-layer composite film. When the separator is a multi-layer composite film, the materials of each layer may be the same or different. The separator may be a separate component located between the positive and negative electrodes, or it may be attached to the surfaces of the positive and negative electrodes.

[0065] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0066] In some embodiments, the battery cell also includes an electrolyte, which acts as a conductor of ions between the positive and negative electrodes. The electrolyte can be liquid, gel-like, or solid. Liquid electrolytes include electrolyte salts and solvents.

[0067] In some embodiments, the electrolyte salt may include at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0068] In some embodiments, the solvent may include at least one selected from ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. Ether solvents may include one or more selected from ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyl tetrahydrofuran, diphenyl ether, and crown ethers.

[0069] Among them, the gel electrolyte includes a polymer as the electrolyte backbone network, combined with an ionic liquid - lithium salt.

[0070] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0071] As an example, polymer solid electrolytes can be polyethers (polyoxyethylene), polysiloxanes, polycarbonates, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, monoionic polymers, polyionic liquids-lithium salts, cellulose, etc.

[0072] As an example, inorganic solid electrolytes may include one or more of the following: oxide solid electrolytes (crystalline perovskite, sodium superconducting ion conductor, garnet, amorphous LiPON thin film), sulfide solid electrolytes (crystalline lithium superconducting ion conductor (lithium germanium phosphate sulfide, silver sulfide germanium ore), amorphous sulfides), halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0073] As an example, composite solid electrolytes are formed by adding inorganic solid electrolyte fillers to polymer solid electrolytes.

[0074] In some implementations, the electrode assembly has a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0075] In some implementations, the electrode assembly has a stacked structure.

[0076] As an example, multiple positive and negative electrodes can be set, and multiple positive and multiple negative electrodes can be stacked alternately.

[0077] As an example, multiple positive electrode plates can be provided, and negative electrode plates can be folded to form multiple stacked folded segments, with a positive electrode plate sandwiched between adjacent folded segments.

[0078] As an example, both the positive and negative electrode plates are folded to form multiple stacked folded segments.

[0079] As an example, multiple separators can be provided, each positioned between any adjacent positive or negative electrode plates.

[0080] As an example, the separators can be continuously arranged, either by folding or rolling between any adjacent positive or negative electrode plates.

[0081] In some implementations, the electrode assembly may be flat or polygonal in shape.

[0082] In some embodiments, the electrode assembly is provided with tabs that allow current to be drawn from the electrode assembly. The tabs include a positive tab and a negative tab.

[0083] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0084] As an example, a battery cell can be a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include, but are not limited to, square battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries.

[0085] The battery device mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells, which are connected in series, parallel, or mixed connections via a busbar.

[0086] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells; as an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells into a single module. As an example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0087] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cell assemblies housed within the housing.

[0088] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0089] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0090] As an example, the enclosure may include a first enclosure body and a second enclosure body. The first enclosure body and the second enclosure body are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, which can be either sealed or unsealed. The first enclosure body may be a top cover or a bottom plate.

[0091] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0092] As an example, the housing can be part of the vehicle's chassis structure. For instance, the housing's roof can be at least part of the vehicle's floor, or the housing's frame can be at least part of the vehicle's crossbeams and longitudinal beams.

[0093] In some embodiments, the battery device refers to an energy storage device, which includes a housing with a door on at least one side. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0094] Battery devices possess outstanding advantages such as high energy density, low environmental pollution, high power density, long service life, wide applicability, and low self-discharge coefficient, making them an important component of today's new energy development. The development of battery technology must simultaneously consider multiple design factors, such as performance parameters like energy density, cycle life, discharge capacity, and charge / discharge rate. Furthermore, the reliability of the battery device must also be taken into account.

[0095] For a typical battery cell, it includes a casing and an electrode assembly housed within the casing. Correspondingly, the casing also has electrode terminals, and a current collector is located inside the casing. Electrical connection between the electrode assembly and the electrode terminals is achieved by welding the current collector to the electrode terminals and then to the tabs. This allows the battery cell to input or output electrical energy through the electrode terminals. In related technologies, since the tabs of the electrode assembly are formed by stacking and closing multiple tabs of the same polarity, to improve the welding quality between the tabs and the current collector, the multiple tabs are usually first closed and ultrasonically pre-welded to form a single tab. The entire assembly is then welded to the current collector, which reduces the possibility of misalignment and movement of the multiple tabs during the welding process. This reduces the risk of incomplete welding between the tabs and the current collector. However, this battery cell structure, after the multiple tabs are gathered and ultrasonically pre-welded, results in some areas of the tab having high strength and hardness. This can lead to localized stress concentration at the edges of the ultrasonically pre-welded areas during use, making the tabs prone to cracking or even breakage. Consequently, there is a risk of unstable or failed connections between the electrode terminals and electrode assemblies during use, which is detrimental to improving the stability and lifespan of the battery cell.

[0096] Based on the above considerations, in order to solve the problems of low stability and short service life of battery cells, this application provides a battery cell including a casing, a first electrode lead, and at least one electrode assembly. The casing has a wall portion. The first electrode lead is disposed in the casing. The electrode assembly is disposed inside the casing and includes a main body portion and a first tab, the first tab being connected to the end of the main body portion facing the wall portion. The first tab includes a root region and a soldering region connected to each other. The root region is connected to the main body portion. The soldering region includes a first region and a second region. The first region is connected to the root region through the second region. The soldering region has a plurality of solder grooves formed on one side of the wall portion's thickness direction. The sum of the areas of all solder grooves in the first region per unit area is greater than the sum of the areas of all solder grooves in the second region per unit area. The soldering region is welded to the first electrode lead to form a first soldering portion, and the first region is connected to and surrounds the outside of the first soldering portion.

[0097] In this type of battery cell, the soldering area of ​​the first tab has multiple solder grooves formed on one side of the wall thickness direction. The first region of the soldering area is interconnected with the root region of the first tab through the second region. By setting the sum of the areas of all solder grooves per unit area in the first region to be greater than the sum of the areas of all solder grooves per unit area in the second region, and by configuring the first region of the soldering area to connect to and surround the first soldering portion, the density of solder grooves increases from the root region to the first region of the soldering area. This results in a structure where the root region, the second region, and the first region of the first tab have progressively increasing overall hardness and compaction density. Furthermore, the first electrode lead is welded to the portion of the soldering area located inside the first region to form the first soldering portion. This battery cell structure allows the second region to form a buffer zone between the first region connected to the first soldering portion and the root region, thus mitigating the impact of the first tab on the main body. The large difference in hardness and compaction density between the connection point and the welding point with the first electrode lead reduces the occurrence of localized stress concentration at the edge of the first area or the first weld mark due to the pulling of the main body or the first electrode lead during use. This helps reduce the risk of localized cracking or breakage of the first electrode during use. On the other hand, it enables the first electrode to be welded to the first electrode lead from an area with relatively high overall hardness and compaction density. This reduces the assembly gap inside the first electrode and between the first electrode and the first electrode lead, thus reducing the occurrence of incomplete or faulty welds. This improves the welding quality and current flow effect between the first electrode and the first electrode lead, and effectively reduces the risk of unstable or failed connections between the first electrode lead and the electrode assembly during use, thereby improving the stability and lifespan of the battery cell.

[0098] The battery cells disclosed in this application can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft. A power system for such an electrical device can be constructed using battery cells and battery devices disclosed in this application. This helps to alleviate problems such as unstable or failed connections of battery cells during use, thereby improving the stability and lifespan of the battery cells.

[0099] This application provides an electrical device that uses a single battery cell or battery assembly as a power source. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0100] For ease of explanation, the following embodiments will be described using a vehicle as an example of an electrical device according to an embodiment of this application.

[0101] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of this application. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery device 100 is installed inside the vehicle 1000. The battery device 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to supply power to the vehicle 1000; for example, the battery device 100 can serve as the operating power source or general power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 controls the battery device 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during startup, navigation, and driving.

[0102] In some embodiments of this application, the battery device 100 can not only serve as the operating power or power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0103] Please refer to Figure 2 and Figure 3 , Figure 2 This is an exploded view of the structure of the battery device 100 provided in some embodiments of this application. Figure 3 This is a schematic diagram of the structure of a battery cell 20 provided in some embodiments of this application. The battery device 100 includes a housing 10 and battery cells 20, which are housed within the housing 10.

[0104] The housing 10 provides assembly space for the battery cell 20, and can adopt various structures. In some embodiments, the housing 10 may include a first housing body 11 and a second housing body 12, which overlap each other, and together define an assembly space for accommodating the battery cell 20. The second housing body 12 may be a hollow structure open at one end, and the first housing body 11 may be a plate-like structure, with the first housing body 11 covering the open side of the second housing body 12 so that the first housing body 11 and the second housing body 12 together define the assembly space; alternatively, the first housing body 11 and the second housing body 12 may both be hollow structures open on one side, with the open side of the first housing body 11 covering the open side of the second housing body 12.

[0105] Of course, the box 10 formed by the first box body 11 and the second box body 12 can be of various shapes, such as a cylinder, a cuboid, or a cube. For example, in... Figure 2 In the middle, the shape of box 10 is a cuboid.

[0106] In the battery device 100, there can be one or more battery cells 20 disposed within the housing 10. When there are multiple battery cells 20 disposed within the housing 10, they can be connected in series, in parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells 20 are connected in both series and parallel configurations. Multiple battery cells 20 can be directly connected in series, in parallel, or in a mixed configuration, and then the entire assembly of the multiple battery cells 20 is housed within the housing 10. Alternatively, the battery device 100 can also consist of multiple battery cells 20 first connected in series, in parallel, or in a mixed configuration to form battery modules, and then multiple battery modules are connected in series, in parallel, or in a mixed configuration to form a whole, which is then housed within the housing 10.

[0107] In some embodiments, the battery device 100 may also include other structures. For example, the battery device 100 may also include a busbar for connecting multiple battery cells 20 to achieve electrical connection between the multiple battery cells 20.

[0108] Each battery cell 20 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited to these. The battery cell 20 can be in the form of a cuboid, a prism, or other shapes. For example, in... Figure 3 In the middle, the battery cell 20 has a cuboid structure.

[0109] According to some embodiments of this application, refer to Figure 3 Please refer to further details. Figure 4 , Figure 5 , Figure 6 , Figure 7 and Figure 8 , Figure 4 This is an exploded view of the structure of a battery cell 20 provided in some embodiments of this application. Figure 5 This is a partial cross-sectional view of a battery cell 20 provided in some embodiments of this application. Figure 6 This is an assembly diagram of the electrode lead-out and the first electrode tab 232 provided in some embodiments of this application. Figure 7 This is a partial cross-sectional view of the electrode lead-out and the first electrode tab 232 after assembly according to some embodiments of this application. Figure 8 for Figure 7The image shows a partial enlarged view of point A on the first electrode tab 232. This application provides a battery cell 20, which includes a housing 21, a first electrode lead-out 22, and at least one electrode assembly 23. The housing 21 has a wall portion 211. The first electrode lead-out 22 is disposed within the housing 21. The electrode assembly 23 is disposed within the housing 21 and includes a main body portion 231 and a first electrode tab 232, the first electrode tab 232 being connected to the end of the main body portion 231 facing the wall portion 211. The first electrode tab 232 includes a root region 2321 and a solder area 2322 that are connected to each other. The root region 2321 is connected to the main body 231. The solder area 2322 includes a first region 23221 and a second region 23222. The first region 23221 is connected to the root region 2321 through the second region 23222. The solder area 2322 has a plurality of solder grooves 23224 formed on one side of the wall in the thickness direction X. The sum of the areas of all solder grooves 23224 in the first region 23221 per unit area is greater than the sum of the areas of all solder grooves 23224 in the second region 23222 per unit area. The solder area 2322 is welded to the first electrode lead 22 to form a first solder part 24, and the first region 23221 is connected to and surrounds the outside of the first solder part 24.

[0110] The outer shell 21 can also be used to contain electrolytes, such as electrolyte solution. The outer shell 21 can have various structural forms, such as a cuboid. Similarly, the outer shell 21 can be made of various materials, such as copper, iron, aluminum, steel, or aluminum alloy.

[0111] In some embodiments, the housing 21 can be a sealed structure or a non-sealed structure. As an example, when the housing 21 is a sealed structure, it can protect the electrode assembly 23 and prevent, to some extent, electrolyte leakage. When the housing 21 is a non-sealed structure, it can still protect the electrode assembly 23, and a sealing bag may be included between the housing 21 and the electrode assembly 23 to encapsulate the electrode assembly 23 and the electrolyte.

[0112] Optionally, the housing 21 may include a housing 212 and an end cap 213. The housing 212 has an internal cavity for accommodating the electrode assembly 23 and has an opening 2121. That is, the housing 212 is a hollow structure with an opening 2121 at one end. The end cap 213 covers the opening 2121 of the housing 212 and forms a sealed connection to form a sealed space for accommodating the electrode assembly 23 and the electrolyte.

[0113] The housing 212 includes a bottom wall and a side wall. The bottom wall is disposed opposite to the end cap 213. The side wall surrounds the bottom wall, and one end of the side wall is connected to the bottom wall, while the other end forms an opening 2121.

[0114] It should be noted that the wall portion 211 of the outer casing 21 can be the end cap 213 of the outer casing 21, or it can be a wall of the housing 212 of the outer casing 21. For example, in... Figure 3 and Figure 4 In this embodiment, the wall portion 211 is the end cap 213. Of course, the structure of the battery cell 20 is not limited to this. In other embodiments, the wall portion 211 can also be the bottom wall of the housing 212 and the end cap 213 that are disposed opposite to each other, or the wall portion 211 can also be the side wall of the housing 212 and the end cap 213 that are adjacent to each other and connected to each other.

[0115] The housing 212 can have various shapes, such as a cuboid or prism structure. The shape of the housing 212 can be determined according to the specific shape of the electrode assembly 23. For example, if the electrode assembly 23 is a cuboid structure, then a cuboid housing 212 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 open at one end. For example, in Figure 3 and Figure 4 In the middle, the shell 212 has a cuboid structure, and correspondingly, the end cap 213 has a rectangular plate structure.

[0116] Of course, it is understandable that the outer casing 21 is not limited to the structure described above. The outer casing 21 can also be other structures. For example, the outer casing 21 can include a housing 212 and two end caps 213. The housing 212 is a hollow structure with openings 2121 formed on both opposite sides. One end cap 213 is fitted onto one opening 2121 of the housing 212 and forms a sealed connection to form a sealed space for accommodating the electrode assembly 23 and the electrolyte. That is, the housing 212 has openings 2121 formed on both opposite sides, and the two end caps 213 are fitted onto both sides of the housing 212 to close the corresponding openings 2121.

[0117] In the embodiments of this application, see Figure 4 and Figure 5 As shown, the electrode assembly 23 includes a main body 231, a first tab 232, and a second tab 233. The main body 231 is the main component of the electrode assembly 23 for chemical reactions to occur inside the battery cell 20. The first tab 232 and the second tab 233 have opposite polarities, that is, the first tab 232 and the second tab 233 are the positive tab and the negative tab of the electrode assembly 23, respectively. The first tab 232 and the second tab 233 are both connected to the main body 231 and are spaced apart.

[0118] The main body 231 of the electrode assembly 23 includes a first electrode 2311, a second electrode 2312, and a separator 2313. The first electrode 2311 and the second electrode 2312 have opposite polarities, i.e., the first electrode 2311 and the second electrode 2312 are the positive electrode and the negative electrode of the electrode assembly 23, respectively. Correspondingly, a first tab 232 is connected to the first electrode 2311, and a second tab 233 is connected to the second electrode 2312. Optionally, the main body 231 of the electrode assembly 23... The structure can be varied. The main body 231 of the electrode assembly 23 can be a wound structure formed by winding the first electrode 2311, the second electrode 2312 and the separator 2313, or a stacked structure formed by alternatingly stacking the first electrode 2311, the second electrode 2312 and the separator 2313. The separator 2313 is disposed between the first electrode 2311 and the second electrode 2312 to insulate and isolate the first electrode 2311 and the second electrode 2312.

[0119] For example, the separator 2313 is a separator membrane, and the main material of the separator membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.

[0120] Optionally, in Figure 4 and Figure 5 In this embodiment, the first electrode 232 and the second electrode 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 electrode 232 and the second electrode 233 may also be structures that are respectively connected to the two ends of the main body 231 in the thickness direction X of the wall.

[0121] For example, the first electrode tab 232 is connected to one end of the first electrode 2311 in the thickness direction X of the wall portion near the wall portion 211, and the second electrode tab 233 is connected to one end of the second electrode 2312 in the thickness direction X of the wall portion near the wall portion 211.

[0122] Among them, combined Figure 6 , Figure 7 and Figure 8As shown, the first tab 232 of the electrode assembly 23 is a multilayer metal foil structure connected to one end of the first electrode 2311 in the thickness direction X of the wall portion. That is, the first tab 232 includes multiple tabs 232a stacked together. Correspondingly, the second tab 233 of the electrode assembly 23 is also a multilayer metal foil structure connected to one end of the second electrode 2312 in the thickness direction X of the wall portion. It should be noted that the first tab 232 and the first electrode 2311 can be separate structures. For example, the first tab 232 and the first current collector of the first electrode 2311 can be welded together. Of course, the first tab 232 and the first electrode 2311 can also be integrally formed. For example, the first current collector of the first tab 232 and the first electrode 2311 can be formed by integrally cutting the same metal foil to form the first tab 232 and the first current collector. Similarly, the second tab 233 and the second electrode 2312 can be separate structures. For example, the second tab 233 and the second current collector of the second electrode 2312 can be welded together. Of course, the second tab 233 and the second electrode 2312 can also be integrally formed. For example, the second current collector of the second tab 233 and the second electrode 2312 can be formed by integrally cutting the same metal foil to form the second tab 233 and the second current collector.

[0123] Optionally, the electrode assembly 23 housed within the housing 21 can be one or more. For example, in... Figure 4 and Figure 5 In this embodiment, the outer casing 21 of the battery cell 20 contains two electrode assemblies 23, which are stacked along the first direction Y. Of course, in other embodiments, the number of electrode assemblies 23 contained in the outer casing 21 of the battery cell 20 can be three, four, five or six, etc.

[0124] In this embodiment, the electrode assembly 23 has a flat region 23a, that is, the flat region 23a is the flat portion of the main body 231 of the electrode assembly 23. For example, refer 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 this application, perpendicular to the thickness direction X of the wall portion. The electrode assembly 23 has a stacked structure, in which case the entire main body 231 of the electrode assembly 23 is a flat region 23a; that is, the main body 231 of the electrode assembly 23 only includes the flat region 23a. Of course, if the electrode assembly 23 has a wound structure, refer to... Figure 10 As shown, Figure 10The image shows a cross-sectional view of the main body 231 of the electrode assembly 23 provided in some embodiments of this application, perpendicular to the thickness direction X of the wall portion. The winding center axis of the electrode assembly 23 extends along the thickness direction X of the wall portion. Correspondingly, the main body 231 also has two bending regions 23b, and the two bending regions 23b are respectively connected to the two opposite ends of the straight region 23a in the second direction Z. The thickness direction X, the first direction Y, and the second direction Z of the wall portion are perpendicular to each other.

[0125] The first electrode 2311 includes a first electrode segment 2311a located in the flat region 23a, and the second electrode 2312 includes a second electrode segment 2312a located in the flat region 23a. The first electrode segment 2311a and the second electrode segment 2312a are stacked and alternately arranged along the first direction Y. Correspondingly, each electrode tab 232a is connected to one end of the first electrode segment 2311a facing the wall portion 211 in the thickness direction X of the wall portion.

[0126] It should be noted that, see Figure 9 As shown, if the electrode assembly 23 has a stacked structure, it includes multiple first electrode pieces 2311 and multiple second electrode pieces 2312. The first electrode pieces 2311 and second electrode pieces 2312 are alternately stacked along the first direction Y. Correspondingly, the first electrode segment 2311a is the first electrode piece 2311, and each first electrode segment 2311a has an electrode tab 232a connected to one end of the wall segment 2311a facing the wall portion 211 in the thickness direction X of the wall portion. The second electrode segment 2312a is the second electrode piece 2312. If the electrode assembly 23 has a wound structure, see [reference needed]. Figure 10 As shown, the first electrode segment 2311a is the straight portion of the first electrode 2311 located within the straight region 23a, and the second electrode segment 2312a is the straight portion of the second electrode 2312 located within the straight region 23a. Correspondingly, the first electrode 2311 also includes a first bent segment 2311b located within the bent region 23b, and the second electrode 2312 also includes a second bent segment 2312b located within the bent region 23b. In the winding direction R of the electrode assembly 23, the first bent segment 2311b connects two adjacent first electrode segments 2311a, and the first bent segment 2311b and the first electrode segment 2311a are alternately arranged. Similarly, in the winding direction R of the electrode assembly 23, the second bent segment 2312b connects two adjacent second electrode segments 2312a, and the second bent segment 2312b and the second electrode segment 2312a are alternately arranged.

[0127] The first electrode tab 232 includes a root region 2321 and a solder area 2322 that are connected to each other. The root region 2321 is connected to the main body 231. That is, the first electrode tab 232 is divided into two regions, namely the root region 2321 and the solder area 2322 that are connected to each other. The solder area 2322 is a structure that is connected to the main body 231 of the electrode assembly 23 through the root region 2321. In other words, the first electrode tab 232 is a structure in which the root region 2321 is connected to the first electrode plate 2311.

[0128] The solder 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, meaning the second area 23222 is adjacent to and directly connected to the root area 2321, and the second area 23222 connects 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 directly connected or indirectly connected. For example, see [link to example]. Figure 6 As shown, a third region 23223 is also formed on the solder area 2322, and the first region 23221 and the second region 23222 are interconnected through the third region 23223.

[0129] See Figure 7 and Figure 8 As shown, the solder area 2322 has a plurality of solder grooves 23224 formed on one side of the wall thickness direction X. That is, the plurality of tabs 232a of the first tab 232 are welded together in the solder area 2322, and the plurality of tabs 232a are welded together and form a plurality of solder grooves 23224 arranged at intervals on one side of the solder area 2322 along the wall thickness direction X.

[0130] In the embodiments of this application, please continue to refer to Figure 7 and Figure 8As shown, the solder area 2322 has a first surface 23225 and a second surface 23226 opposite to each other in the thickness direction X of the wall. Multiple electrode tabs 232a are welded together to form multiple solder grooves 23224 on the solder area 2322. The solder grooves 23224 are located between the first surface 23225 and the second surface 23226, and the solder grooves 23224 penetrate the first surface 23225, forming slots 23224a on the first surface 23225. The solder grooves 23224 are groove structures formed on the first surface 23225 by welding multiple electrode tabs 232a together. For example, in ultrasonic welding... Accordingly, multiple tabs 232a are welded together to form multiple second solder marks 2323. The second solder marks 2323 are connected to the multiple tabs 232a. The second solder marks 2323 are arranged in a one-to-one correspondence with the solder grooves 23224. A second solder mark 2323 is formed at the bottom of each solder groove 23224. That is, the bottom wall of each solder groove 23224 is at least a part of a second solder mark 2323, so that a second solder mark 2323 is formed at the bottom of each solder groove 23224. That is, a second solder mark 2323 is formed at the corresponding position of each solder groove 23224 in the thickness direction X of the wall.

[0131] It should be noted that the portions of the multiple tabs 232a of the first tab 232 within the root region 2321 are stacked on top of each other and not fixedly connected. The end of the tab 232a in the root region 2321 that is away from the solder area 2322 is connected to the first tab 2311. The portions of the multiple tabs 232a of the first tab 232 within the solder area 2322 are fixedly connected to each other through the second solder area 2323.

[0132] It should be noted that the second solder mark 2323 is the area where multiple tabs 232a are welded together to form a fused area or the area where solder marks are formed.

[0133] The sum of the areas of all solder grooves 23224 within a unit area of ​​the first zone 23221 is greater than the sum of the areas of all solder grooves 23224 within a unit area of ​​the second zone 23222. In other words, in the projection plane perpendicular to the thickness direction X of the wall portion, the sum of the orthographic projection areas of the groove walls of all solder grooves 23224 within a unit area of ​​the first zone 23221 is greater than the sum of the orthographic projection areas of the groove walls of all solder grooves 23224 within a unit area of ​​the second zone 23222. That is, the proportion of the sum of the orthographic projection areas of the groove walls of all solder grooves 23224 within a unit area of ​​the first zone 23221 is greater than the proportion of the orthographic projection areas of the groove walls of all solder grooves 23224 within a unit area of ​​the second zone 23222. Similarly, the sum of the areas of all solder grooves 23224a within a unit area of ​​the first zone 23221 is greater than the sum of the areas of all solder grooves 23224a within a unit area of ​​the second zone 23222. That is, the proportion of the sum of the areas of all solder grooves 23224a within a unit area of ​​the first zone 23221 is greater than the proportion of the sum of the areas of all solder grooves 23224a within a unit area of ​​the second zone 23222. It should be noted that when comparing the sum of the areas of solder grooves 23224 within a unit area of ​​the first zone 23221 and the second zone 23222, the unit of area is the same.

[0134] The solder area 2322 is welded to the first electrode lead 22 to form the first solder part 24, and the first region 23221 is connected to and surrounds the outside of the first solder part 24. That is, the first electrode tab 232 is a structure in which the solder area 2322 with solder groove 23224 is welded to the first electrode lead 22, and the first solder part 24 is formed accordingly, so that part of the first solder part 24 is embedded in the solder area 2322 and part of the first solder part 24 is embedded in the first electrode lead 22. Correspondingly, the first region 23221 with a relatively large density of solder groove 23224 in the solder area 2322 of the first electrode tab 232 is a structure that surrounds the first solder part 24 and is directly connected to the first solder part 24, so that the part of the first solder part 24 located in the solder area 2322 is a structure that is connected to the other part of the first electrode tab 232 through the first region 23221. It should be noted that the second soldering portion 2323 and soldering groove 23224 within the soldering area 2322 are formed by pre-welding multiple tabs 232a of the first electrode tab 232 before welding and assembling the first electrode tab 232 and the first electrode lead 22. Furthermore, multiple soldering grooves 23224 are also formed in the area where the soldering area 2322 is welded to the first electrode lead 22. The area of ​​all soldering grooves 23224 per unit area in the area where the soldering area 2322 is welded to the first electrode lead 22 is equal to the sum of the areas of all soldering grooves 23224 per unit area in the first area 23221. That is, the area of ​​the soldering area 2322 and the first electrode lead 22 is equal to the sum of the areas of all soldering grooves 23224 per unit area in the first area 23221. The density of the solder groove 23224 in the welding area is the same as the density of the solder groove 23224 in the first area 23221. After the solder area 2322 is welded to the first electrode lead 22 to form the first solder part 24, the solder groove 23224 in the area where the solder area 2322 is welded to the first electrode lead 22 is covered and filled by the first solder part 24. The second solder part 2323 in the area where the solder area 2322 is welded to the first electrode lead 22 is fused with the first solder part 24 to form an integral structure, that is, the second solder part 2323 in the area where the solder area 2322 is welded to the first electrode lead 22 is embedded in the first solder part 24.

[0135] It should be noted that the first solder mark 24 is the area where the solder mark area 2322 and the first electrode lead-out member 22 are welded together to form a fused area or a solder mark area.

[0136] In this embodiment, the first electrode lead-out member 22 serves as the first tab 232 of the electrode assembly 23, so as to act as the output or input electrode of the battery cell 20, thereby enabling the output or input of electrical energy of the battery cell 20.

[0137] The first electrode lead-out member 22 is insulated and installed on the outer casing 21. That is, there is no electrical connection between the first electrode lead-out member 22 and the outer casing 21. Optionally, the first electrode lead-out member 22 can be disposed on the wall portion 211 of the outer casing 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 portion 231 in the thickness direction X of the wall portion. Of course, the first electrode lead-out member 22 can also be disposed on other walls of the outer casing 21.

[0138] The first electrode lead-out hole 2111 is inserted into the wall portion 211 and is insulatedly installed on the wall portion 211. That is to say, there is no electrical connection between the first electrode lead-out member 22 and the wall portion 211 of the outer casing 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.

[0139] For example, in this embodiment, 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, which is a structure that penetrates the wall portion 211 along the thickness direction X. The electrode terminal 221 is disposed within the first electrode lead-out hole 2111 of the wall portion 211 along the thickness direction X. Correspondingly, the electrode terminal 221 is welded to the solder area 2322 to form a first solder area 24. Of course, in other embodiments, the first electrode lead-out member 22 may also include an electrode terminal 221 and a current collector. The electrode terminal 221 is disposed on the housing 21, the current collector is welded to the electrode terminal 221, and the current collector is welded to the first area 23221 to form a first solder area 24.

[0140] In some embodiments, see Figure 3 and Figure 4 As shown, the battery cell 20 may also include a second electrode lead 25, which is disposed on the housing 21 and electrically connected to the second tab 233 of the electrode assembly 23, so that the second electrode lead 25 and the first electrode lead 22 can cooperate to input or output the electrical energy of the battery cell 20.

[0141] For example, see Figure 4 As shown, the second electrode lead-out member 25 is also provided 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, the wall portion 211 is provided with a second electrode lead-out hole, which penetrates the wall portion 211 along the thickness direction X. The second electrode lead-out member 25 passes through the second electrode lead-out hole of the wall portion 211 and is insulated and installed on the wall portion 211. That is to say, no electrical connection is formed between the second electrode lead-out member 25 and the wall portion 211 of the outer casing 21.

[0142] It should be noted that the second electrode tab 233 can have the same structure as the first electrode tab 232. Similarly, the assembly structure between the second electrode lead 25 and the second electrode tab 233 can be the same as the assembly structure between the first electrode lead 22 and the first electrode tab 232. That is to say, the second electrode tab 233 can also have a root region 2321, a soldering area 2322, and a soldering groove 23224 provided on the soldering area 2322. Alternatively, the part of the soldering area 2322 of the second electrode tab 233 located inside the first region 23221 can be welded to the second electrode lead 25.

[0143] In some embodiments, see Figure 3 and Figure 4 As shown, the battery cell 20 may also include a pressure relief component 26, which is disposed on the housing 21 and is used to release the internal pressure of the battery cell 20 when the internal pressure or temperature of the battery cell 20 reaches a predetermined value.

[0144] For example, the pressure relief component 26 is disposed on the end cap 213 of the housing 21. Of course, in other embodiments, the pressure relief component 26 may also be disposed on the housing 212 of the housing 21. Similarly, the pressure relief component 26 and the housing 21 may be integrally formed or separately disposed. If the pressure relief component 26 and the housing 21 are separately disposed, the pressure relief component 26 may be connected to the housing 21 by welding or other means. Correspondingly, the pressure relief component 26 may be a component such as an explosion-proof valve, explosion-proof disc, gas valve, pressure relief valve or safety valve. If the pressure relief component 26 and the housing 21 are integrally formed, the pressure relief component 26 is a region on the housing 21 with a weak structure, such as a region on the housing 21 with a groove.

[0145] In this embodiment, a plurality of solder grooves 23224 are formed on the surface of the solder area 2322 of the first electrode tab 232 on one side of the wall thickness direction X. The first region 23221 of the solder area 2322 is interconnected with the root region 2321 of the first electrode tab 232 through the second region 23222. The sum of the areas of all solder grooves 23224 in the first region 23221 per unit area is set to be greater than the sum of the areas of all solder grooves 23224 in the second region 23222 per unit area. The first region 23221 of the solder area 2322 is configured to connect to and surround the first solder portion 2. The structure configured such that the density of the first region 23221 of the first tab 232, from the root region 2321 to the solder area 2322, increases with the density of the solder groove 23224. This achieves a structure where the root region 2321, the second region 23222, and the first region 23221 of the first tab 232 have progressively increasing overall hardness and compaction density. Furthermore, the first electrode lead 22 is welded to the portion of the solder area 2322 located inside the first region 23221 to form the first solder portion 24. This structure in the battery cell 20 allows the second region 23222 to connect with the first solder portion 24. A buffer zone is formed between the first region 23221 and the root region 2321 to alleviate the phenomenon of excessively large spans in hardness and compaction density between the position where the first electrode tab 232 is connected to the main body 231 and the position where it is welded to the first electrode lead 22. This reduces the phenomenon of local stress concentration at the edge of the first region 23221 or the first solder mark 24 due to the pulling of the main body 231 or the first electrode lead 22 during use, which helps to reduce the risk of local cracking or breakage of the first electrode tab 232 during use. On the other hand, it can achieve overall hardness and compaction density of the first electrode tab 232. The structure of welding and assembling the area with relatively high density to the first electrode lead 22 can reduce the assembly gap inside the first tab 232 and between the first tab 232 and the first electrode lead 22. This reduces the occurrence of phenomena such as incomplete welding or poor welding between the first tab 232 and the first electrode lead 22, which is beneficial to improving the welding quality and current flow effect between the first tab 232 and the first electrode lead 22. In turn, it can effectively reduce the risk of unstable connection or connection failure between the first electrode lead 22 and the electrode assembly 23 during use, thereby improving the stability and service life of the battery cell 20.

[0146] According to some embodiments of this application, see Figure 7 and Figure 8As shown, the thickness of the portion of the first region 23221 without the solder groove 23224 is equal to the thickness of the portion of the second region 23222 without the solder groove 23224. That is, the surface of the first region 23221 with the solder groove 23224 and the surface of the second region 23222 with the solder groove 23224 are coplanar, and the surface of the first region 23221 facing away from the solder groove 23224 and the surface of the second region 23222 facing away from the solder groove 23224 are also coplanar.

[0147] In this embodiment, by setting the thickness of the first region 23221 and the second region 23222 of the soldering area 2322 to be the same in the area without the solder groove 23224, the first region 23221 and the second region 23222 of the soldering area 2322 are made into a smooth transition structure. This is beneficial to improving the overall flatness of the soldering area 2322 of the first electrode tab 232. On the one hand, it can reduce the difficulty of welding and assembling the soldering area 2322 and the first electrode lead 22, and improve the welding quality between the soldering area 2322 and the first electrode lead 22. On the other hand, it can alleviate the stress concentration phenomenon caused by the different thickness of the first region 23221 and the second region 23222 in the area without the solder groove 23224. This is beneficial to reduce the risk of breakage of the first electrode tab 232 during use, thereby improving the stability and service life of the battery cell 20.

[0148] According to some embodiments of this application, see Figure 6 , Figure 7 and Figure 8 As shown, the area of ​​the first zone 23221 is 50%-80% of the sum of the areas of all solder grooves 23224 within a unit area.

[0149] Among them, the sum of the areas of all solder grooves 23224 in the first zone 23221 within a unit area accounts for 50%-80%, that is, the ratio of the sum of the areas of the groove openings 23224a of all solder grooves 23224 in the first zone 23221 within a unit area to the unit area is 0.5-0.8.

[0150] For example, the percentage of the sum of the areas of all solder grooves 23224 in the first zone 23221 within a unit area can be 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%, etc.

[0151] In this embodiment, the area ratio of the sum of all solder grooves 23224 in the first region 23221 of the soldering area 2322 is set to be greater than or equal to 50%. This increases the density of solder grooves 23224 in the first region 23221 of the soldering area 2322, thereby improving the overall hardness and compaction density of the first region 23221. This facilitates the welding assembly of the soldering area 2322 and the first electrode lead-out 22, and reduces the occurrence of incomplete or faulty welds between the soldering area 2322 and the first electrode lead-out 22. This further improves the overall hardness and compaction density of the soldering area 2322 and the first electrode lead-out 22. On the one hand, the welding quality and current flow effect between the first electrode leads 22 are improved. On the other hand, the ratio of the sum of the areas of all solder grooves 23224 in the first region 23221 of the solder area 2322 is set to less than or equal to 80%. This helps to reduce the difficulty of forming solder grooves 23224 in the first region 23221 and can reduce the stress concentration phenomenon at the edge of the first region 23221 during use caused by the excessive density of solder grooves 23224 in the first region 23221. This reduces the risk of cracking or breakage of the first electrode tab 232 at the edge of the first region 23221.

[0152] According to some embodiments of this application, please continue to refer to Figure 6 , Figure 7 and Figure 8 As shown, the area of ​​the second zone 23222 is 20%-60% of the sum of the areas of all solder grooves 23224 within a unit area.

[0153] Among them, the area of ​​all solder grooves 23224 in the second zone 23222 accounts for 20%-60% of the total area, that is, the ratio of the area of ​​the groove opening 23224a of all solder grooves 23224 in the second zone 23222 to the unit area is 0.2-0.6.

[0154] For example, the percentage of the sum of the areas of all solder grooves 23224 in the second zone 23222 within a unit area 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.

[0155] In this embodiment, the proportion of the sum of the areas of all solder grooves 23224 in the second region 23222 of the soldering area 2322 is set to be greater than or equal to 20%. This allows the second region 23222 to act as a buffer between the root region 2321 (where no solder grooves 23224 are provided) and the first region 23221 (where the density of solder grooves 23224 is higher). This further reduces the phenomenon of local stress concentration at the edge of the first region 23221 caused by the pulling of the main body 231 or the first electrode lead-out member 22 during use of the first electrode tab 232, which is beneficial to further reduce the stress on the first electrode tab 232. To mitigate the risk of localized cracking or breakage during use, the area ratio of the sum of all solder grooves 23224 in the second zone 23222 of the solder area 2322 is set to be less than or equal to 60% within a unit area. This allows for a better connection and transition between the root zone 2321 and the second zone 23222, which helps alleviate stress concentration between the second zone 23222 and the root zone 2321 caused by excessive density of solder grooves 23224 in the second zone 23222. This reduces the risk of cracking or breakage at the connection point between the second zone 23222 and the root zone 2321 during use.

[0156] According to some embodiments of this application, see Figure 6 As shown, the second region 23222 surrounds the outside of the first region 23221. That is, the second region 23222 is a ring structure surrounding the first region 23221, and the first region 23221 is located inside the second region 23222.

[0157] In this embodiment, by setting the second region 23222 to surround the first region 23221, the area with lower density of the solder groove 23224 can better protect the area with higher density of the solder groove 23224. This facilitates the connection between the first region 23221 and the root region 2321 through the second region 23222, which helps reduce the forming difficulty of the solder area 2322 of the first tab 232. On the other hand, the second region 23222 can better buffer stress between the root region 2321 and the first region 23221, which helps to further reduce the risk of cracking or breakage of the first tab 232 due to local stress concentration during use.

[0158] According to some embodiments of this application, in conjunction with Figure 5 , Figure 6 and Figure 7As shown, the solder area 2322 is welded to the first electrode lead-out member 22 to form a first solder part 24. The solder area 2322 has a first surface 23225 and a second surface 23226 facing each other in the thickness direction X of the wall. The first surface 23225 has a plurality of solder grooves 23224. Along the thickness direction X of the wall, the second surface 23226 faces and abuts against the first electrode lead-out member 22, and the first solder part 24 passes through the second surface 23226.

[0159] Wherein, the first surface 23225 and the second surface 23226 are the two sides of the solder area 2322 in the thickness direction X of the wall portion. Correspondingly, the first surface 23225 is the surface of the solder area 2322 where the solder groove 23224 is provided, and the second surface 23226 is the surface of the solder area 2322 in the thickness direction X of the wall portion that faces and abuts against the first electrode lead 22.

[0160] The solder area 2322 is welded to the first electrode lead 22 to form a first solder part 24. It should be noted that the first solder part 24 is a solder structure that connects the solder area 2322 and the first electrode lead 22. Part of the first solder part 24 is located within the solder area 2322 and part of the first solder part 24 is located within the first electrode lead 22, so that the first solder part 24 can connect the solder area 2322 and the first electrode lead 22. The part of the first solder part 24 located within the solder area 2322 is directly connected to and surrounded by the first area 23221. Correspondingly, the first solder part 24 passes through the second surface 23226, that is, the second surface 23226 is also welded to the electrode lead. It should be noted that the first solder part 24 can be a structure that only passes through the second surface 23226. Of course, the first solder part 24 can also be a structure that passes through both the second surface 23226 and the first surface 23225.

[0161] For example, see Figure 5 and Figure 7 As shown, the solder area 2322 and the first electrode lead 22 are connected by soldering from the side of the solder area 2322 away from the first electrode lead 22, such that the first solder portion 24 extends at least partially from the first surface 23225 into the first electrode lead 22, and the first solder portion 24 extends at least partially from the first surface 23225 through the second surface 23226 and into the first electrode lead 22 in the thickness direction X of the wall portion.

[0162] For example, the solder area 2322 and the first electrode lead-out 22 are structures welded by laser.

[0163] In this embodiment, the solder groove 23224 of the solder area 2322 is disposed on the first surface 23225 of the solder area 2322, and the second surface 23226 of the solder area 2322 faces and abuts against the first electrode lead 22. The first solder part 24 formed by the solder connection of the solder area 2322 and the first electrode lead 22 passes through the second surface 23226. This makes the solder area 2322 such that the surface of the side without the solder groove 23224 is welded to the first electrode lead 22. This reduces the influence of the solder groove 23224 on the welding connection between the solder area 2322 and the first electrode lead 22, which helps to reduce the phenomenon of poor soldering between the solder area 2322 and the first electrode lead 22, thereby improving the welding quality between the solder area 2322 and the first electrode lead 22.

[0164] In some embodiments, see Figure 5 , Figure 7 and Figure 8 As shown, the second surface 23226 is a plane. That is, the second surface 23226 of the solder area 2322 facing the first electrode lead-out member 22 is a flat and smooth planar structure without obvious pits or protrusions.

[0165] In this embodiment, by setting the second surface 23226 of the solder area 2322 facing the first electrode lead 22 as a flat plane, it is beneficial to further reduce the welding gap between the solder area 2322 and the first electrode lead 22, thereby further reducing the phenomenon of incomplete soldering between the solder area 2322 and the first electrode lead 22, so as to further improve the welding quality between the solder area 2322 and the first electrode lead 22.

[0166] According to some embodiments of this application, see Figure 6 and Figure 7 As shown, the solder area 2322 may further include at least one third area 23223, with the first area 23221 and the second area 23222 connected through the third area 23223. The sum of the areas of all solder grooves 23224 within a unit area of ​​the third area 23223 is greater than the sum of the areas of all solder grooves 23224 within a unit area of ​​the second area 23222, and the sum of the areas of all solder grooves 23224 within a unit area of ​​the third area 23223 is less than the sum of the areas of all solder grooves 23224 within a unit area of ​​the first area 23221.

[0167] The third zone 23223 is a structure connected between the first zone 23221 and the second zone 23222, such that the first zone 23221 and the second zone 23222 are indirectly connected through the third zone 23223.

[0168] The sum of the areas of all solder grooves 23224 within a unit area of ​​the third zone 23223 is greater than the sum of the areas of all solder grooves 23224 within a unit area of ​​the second zone 23222. In other words, in the projection plane perpendicular to the thickness direction X of the wall portion, the sum of the orthographic projection areas of the groove walls of all solder grooves 23224 within a unit area of ​​the third zone 23223 is greater than the sum of the orthographic projection areas of the groove walls of all solder grooves 23224 within a unit area of ​​the second zone 23222. That is, the proportion of the sum of the orthographic projection areas of the groove walls of all solder grooves 23224 within a 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 wall surfaces of all solder grooves 23224 within a unit area of ​​zone 23222 is similar to the proportion of the sum of the areas of the openings 23224a of all solder grooves 23224 within a unit area of ​​zone 23223. In other words, the proportion of the sum of the areas of the openings 23224a of all solder grooves 23224 within a unit area of ​​zone 23223 is greater than the proportion of the sum of the areas of the openings 23224a of all solder grooves 23224 within a unit area of ​​zone 23222.

[0169] The sum of the areas of all solder grooves 23224 within a unit area of ​​the third zone 23223 is less than the sum of the areas of all solder grooves 23224 within a unit area of ​​the first zone 23221. In other words, in the projection plane perpendicular to the thickness direction X of the wall portion, the sum of the orthographic projection areas of the groove walls of all solder grooves 23224 within a unit area of ​​the third zone 23223 is less than the sum of the orthographic projection areas of the groove walls of all solder grooves 23224 within a unit area of ​​the first zone 23221. That is, the proportion of the sum of the orthographic projection areas of the groove walls of all solder grooves 23224 within a unit area of ​​the third zone 23223 is less than that of the first zone 23221. The proportion of the sum of the areas of the orthographic projections of the wall surfaces of all solder grooves 23224 within a unit area of ​​zone 23221 is similar to the proportion of the sum of the areas of the openings 23224a of all solder grooves 23224 within a unit area of ​​zone 23223. In other words, the proportion of the sum of the areas of the openings 23224a of all solder grooves 23224 within a unit area of ​​zone 23223 is less than the proportion of the sum of the areas of the openings 23224a of all solder grooves 23224 within a unit area of ​​zone 23221.

[0170] It should be noted that when comparing the sum of the areas of the solder grooves 23224 in the first zone 23221, the second zone 23222, and the third zone 23223, the units of the units of the units of the areas are the same.

[0171] In this embodiment, a third region 23223 is connected between the first region 23221 and the second region 23222 of the solder area 23222. The sum of the areas of all solder grooves 23224 in the third region 23223 per unit area is greater than the sum of the areas of all solder grooves 23224 in the second region 23222 per unit area, and the sum of the areas of all solder grooves 23224 in the third region 23223 per unit area is less than the sum of the areas of all solder grooves 23224 in the first region 23221 per unit area. This makes the root region 2321, the second region 23222, the third region 23223, and the first region 23222 of the first tab 2322 all connected. The structure 21, with its increasing overall hardness and compaction density, is beneficial for further enhancing the buffering effect between the root region 2321 and the first region 23221. This helps to alleviate the phenomenon of excessively large spans in hardness and compaction density between the first electrode tab 232 and the position where it is connected to the main body 231 and welded to the first electrode lead 22. Consequently, it can further reduce the phenomenon of local stress concentration at the edge of the first region 23221 caused by the pulling of the main body 231 or the first electrode lead 22 during use, and further reduce the risk of local cracking or breakage of the first electrode tab 232 during use.

[0172] For example, in Figure 6 In this embodiment, only one third region 23223 is connected between the first region 23221 and the second region 23222. Of course, in some embodiments, the battery cell 20 can also be other structures. For example, the solder area 2322 can include multiple third regions 23223. Along the direction from the first region 23221 to the second region 23222, multiple third regions 23223 are sequentially connected between the first region 23221 and the second region 23222. In each pair of adjacent third regions 23223, the sum of the areas of all solder grooves 23224 in the third region 23223 closer to the first region 23221 within a unit area is greater than the sum of the areas of all solder grooves 23224 in the third region 23223 closer to the second region 23222 within a unit area.

[0173] In this context, along the direction from the first zone 23221 to the second zone 23222, multiple third zones 23223 are sequentially connected between the first zone 23221 and the second zone 23222. That is to say, multiple third zones 23223 are connected between the first zone 23221 and the second zone 23222, and the multiple third zones 23223 are arranged and connected sequentially between the first zone 23221 and the second zone 23222 along the direction from the first zone 23221 to the second zone 23222.

[0174] In each pair of adjacent third zones 23223, the sum of the areas of all solder grooves 23224 in the third zone 23223 closer to the first zone 23221 within a unit area is greater than the sum of the areas of all solder grooves 23224 in the third zone 23223 closer to the second zone 23222 within a unit area. In other words, in each pair of adjacent third zones 23223, and in the projection plane perpendicular to the thickness direction X of the wall portion, the area of ​​the third zone 23223 closer to the first zone 23221 within a unit area is greater than the sum of the areas of all solder grooves 23224 in the third zone 23223 closer to the second zone 23222 within a unit area. The sum of the orthographic projection areas of the wall surfaces of all solder grooves 23224 within the first zone 23221 is greater than the sum of the orthographic projection areas of the wall surfaces of all solder grooves 23224 within a unit area of ​​the third zone 23223, which is far from the first zone 23221. In other words, the percentage of the sum of the orthographic projection areas of the wall surfaces of all solder grooves 23224 within a unit area of ​​the third zone 23223, which is close to the first zone 23221, is greater than the percentage of the sum of the orthographic projection areas of the wall surfaces of all solder grooves 23224 within a unit area of ​​the third zone 23223, which is far from the first zone 23221. The proportion of the sum of the areas of the orthographic projections of the wall surfaces of slots 4 is similar. Similarly, the sum of the areas of the slot openings 23224a of all solder grooves 23224 within a unit area of ​​the third zone 23223, which is closer to the first zone 23221, is greater than the sum of the areas of the slot openings 23224a of all solder grooves 23224 within a unit area of ​​the third zone 23223, which is farther from the first zone 23221. That is, the sum of the areas of the slot openings 23224a of all solder grooves 23224 within a unit area of ​​the third zone 23223, which is closer to the first zone 23221, is greater than the sum of the areas of the slot openings 23224a of all solder grooves 23224 within a unit area of ​​the third zone 23223, which is farther from the first zone 23221. The proportion of the sum of the areas of 224a is greater than the proportion of the sum of the areas of the openings 23224a of all solder grooves 23224 in the third region 23223 that is far away from the first region 23221. Correspondingly, the density of solder grooves 23224 in the multiple third regions 23223 connected between the first region 23221 and the second region 23222 is a structure that decreases sequentially from the third region 23223 near the first region 23221 to the third region 23223 near the second region 23222.

[0175] In this embodiment, by setting a plurality of third regions 23223 sequentially connected between the first region 23221 and the second region 23222, and in each pair of adjacent third regions 23223, the sum of the areas of all solder grooves 23224 in the third region 23223 closer to the first region 23221 within a unit area is greater than the sum of the areas of all solder grooves 23224 in the third region 23223 closer to the second region 23222 within a unit area, the area between the second region 23222 and the first region 23221 is structured so that the overall hardness and compaction density increase sequentially through the plurality of third regions 23223. This can further improve the buffering effect between the second region 23222 and the first region 23221, which is beneficial to further reduce the phenomenon of local stress concentration at the edge of the first region 23221 due to the pulling of the main body 231 or the first electrode lead-out member 22 during the use of the first electrode tab 232, thereby further reducing the risk of local cracking or breakage of the first electrode tab 232 during use.

[0176] In some embodiments, see Figure 6 As shown, the third region 23223 surrounds the outside of the first region 23221, and the second region 23222 surrounds the outside of the third region 23223. That is, both the second region 23222 and the third region 23223 are annular structures surrounding the first region 23221, with the first region 23221 located inside the third region 23223 and the third region 23223 located inside the second region 23222, making the third region 23223 the outermost annular structure.

[0177] Among them, Figure 6 In the soldering area 2322, only one third area 23223 is provided. Correspondingly, the third area 23223 and the second area 23222 are arranged to surround the outer side of the first area 23221 from the inside to the outside. Of course, it should be noted that in the embodiment where the soldering 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 arranged to surround the outer side of the first area 23221 from the inside to the outside, and the second area 23222 surrounds the outer side of the multiple third areas 23223.

[0178] In this embodiment, by setting the third region 23223 to surround the first region 23221 and setting the second region 23222 to surround the third region 23223, the second region 23222, the third region 23223 and the first region 23221 are arranged in a sequentially surrounding structure. This allows the less dense area of ​​the solder groove 23224 to better protect the more dense area of ​​the solder groove 23224. As a result, the second region 23222 and the third region 23223 can better buffer stress between the first region 23221 and the root region 2321, which is beneficial to further reduce the risk of cracking or breakage of the first tab 232 due to local stress concentration during use.

[0179] According to some embodiments of this application, in conjunction with Figure 5 and Figure 6 As shown, the root region 2321 and the solder area 2322 are arranged and connected along the extension direction of the first tab 232.

[0180] The extension direction of the first electrode 232 is the direction in which the first electrode 232 extends from the end of the first electrode 232 connected to the main body 231 to the end away from the main body 231, or from the end of the first electrode 232 away from the main body 231 to the end connected to the main body 231 along the trajectory of the first electrode 232 itself.

[0181] The root region 2321 and the solder area 2322 are arranged and connected along the extension direction of the first tab 232. That is, in the extension direction of the first tab 232, the solder area 2322 is arranged at intervals and not connected to the main body 231, so that the solder area 2322 is a structure that is connected to the main body 231 through the root region 2321.

[0182] In this embodiment, by setting the root region 2321 and the solder area 2322 to be arranged along the extension direction of the first tab 232, when the main body 231 or the first electrode lead 22 pulls on the first tab 232 during use, the second region 23222 can play a better buffering role on the root region 2321 and the first region 23221 in the stress transmission path. This can further reduce the phenomenon of local stress concentration at the edge of the first region 23221 or the first solder area 24 due to the pulling of the main body 231 or the first electrode lead 22 during use, which is beneficial to further reduce the risk of local cracking or breakage of the first tab 232 during use.

[0183] According to some embodiments of this application, in conjunction with Figure 6 , Figure 8 and Figure 9As shown, the main body 231 has a flat region 23a, which includes a plurality of first pole segments 2311a stacked along the first direction Y. A first pole tab 232 is connected to one end of the first pole segment 2311a near the wall 211 in the thickness direction X of the wall. The first pole tab 232 has two opposing first edges 2324 in the second direction Z. The thickness direction X of the wall, the first direction Y, and the second direction Z are perpendicular to each other. The second region 23222 is adjacent to the root region 2321, and a plurality of solder grooves 23224 adjacent to the root region 2321 in the second region 23222 are arranged along a preset trajectory line 23227. The preset trajectory line 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 respectively.

[0184] The flat region 23a also includes a plurality of second pole segments 2312a, the second pole segments 2312a having 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 tab 232a of the first pole tab 232 is connected to one end of the first pole segment 2311a near the wall portion 211 in the thickness direction X of the wall portion.

[0185] The first tab 232 has two opposing first edges 2324 in the second direction Z, wherein the second direction Z is also the width direction of the first tab 232 and the width direction of each tab piece 232a. Correspondingly, the first edge 2324 is also the edge of the second tab 233 on one side in its width direction.

[0186] The second region 23222 is adjacent to the root region 2321, and the multiple solder grooves 23224 in the second region 23222 that are adjacent to the root region 2321 are arranged along the preset trajectory line 23227. That is to say, the preset trajectory line 23227 is the trajectory line structure formed by connecting the first surface 23225 of the solder area 23222 in the second region 23222, the multiple solder grooves 23224 that are closest to the root region 2321 in sequence.

[0187] The preset trajectory line 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 respectively. That is, the edge region of the side of the first electrode 232 where the solder groove 23224 is provided is connected to the straight segment 23227a of the preset trajectory line 23227 through the arc segments 23227b, so that the preset trajectory line 23227 is a structure in which the arc transitions to the first edge 2324.

[0188] In the embodiments of this application, see Figure 6 As shown, the end of the arc segment 23227b connected to the straight segment 23227a is further 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 curved towards the second region 23222 in the extension direction of the first electrode 232.

[0189] In this embodiment, the plurality of solder grooves 23224 adjacent to the root region 2321 in the second region 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 transition to the two opposite first edges 2324 of the first tab 232 in the second direction Z through the two arc segments 23227b respectively, the edges of the second region 23222 and the first tab 2322 can be connected. 2. Both first edges 2324 opposite each other in the second direction Z are arc transition structures to reduce stress concentration at the connection position between the edge of the second region 23222 and the first edge 2324 during use. This can alleviate tearing and other phenomena at the connection position between the first tab 232 and the edge of the second region 23222 and the first edge 2324, thereby further reducing the risk of unstable connection or connection failure of the first electrode lead 22 and the electrode assembly 23 during use, and further improving the stability and service life of the battery cell 20.

[0190] According to some embodiments of this application, see Figure 4 , Figure 5 and Figure 6 As shown, the first electrode lead-out member 22 is an electrode terminal 221 disposed on the wall portion 211. The electrode terminal 221 is welded to the solder area 2322 to form the first solder area 24.

[0191] The first electrode lead-out member 22 is an electrode terminal 221 disposed on the wall portion 211 and passing through the wall portion 211. That is to say, the first tab 232 and the electrode terminal 221 of the battery cell 20 are directly welded together. In other words, the first electrode lead-out member 22 only includes the electrode terminal 221, so that the first tab 232 and the electrode terminal 221 are not connected by other components such as current collectors. Correspondingly, the battery cell 20 is a structure without an adapter plate.

[0192] 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 collector, and the solder area 2322 of the first tab 232 is soldered to the current collector, and the current collector and the electrode terminal 221 are soldered together.

[0193] In this embodiment, by setting the first electrode lead-out member 22 as an electrode terminal 221 mounted on the wall portion 211, and directly welding the electrode terminal 221 to the solder area 2322, an electrical connection between the electrode assembly 23 and the first electrode lead-out member 22 is achieved. With this structure, the battery cell 20 does not need to further provide current collectors or other structures for connecting the electrode terminal 221 and the solder area 2322 inside the casing 21. On the one hand, it can improve the internal space utilization of the battery cell 20 and optimize the weight of the battery cell 20 to improve the energy density of the battery cell 20. On the other hand, it can shorten the current path between the electrode assembly 23 and the first electrode lead-out member 22 to reduce the internal resistance between the electrode assembly 23 and the first electrode lead-out member 22, thereby improving the current flow effect between the electrode assembly 23 and the first electrode lead-out member 22 and improving the performance of the battery cell 20.

[0194] In some embodiments, see Figure 5 and Figure 6 As shown, the solder area 2322 and the first electrode lead 22 are arranged along the thickness direction X of the wall portion, and the solder area 2322 and the first electrode lead 22 are welded together to form a first solder portion 24. Along the thickness direction X of the wall portion, at least a portion of the first solder portion 24 extends from the surface of the solder area 2322 on the side opposite to the first electrode lead 22 into the first electrode lead 22.

[0195] The soldering area 2322 and the first electrode lead-out member 22 are arranged along the thickness direction X of the wall portion, and the soldering area 2322 is located between the first electrode lead-out member 22 and the main body portion 231 in the thickness direction X of the wall portion.

[0196] Along the thickness direction X of the wall portion, at least a portion of the first solder mark 24 extends from the surface of the solder mark area 2322 away from the first electrode lead 22 into the first electrode lead 22. That is, the soldering assembly between the solder mark area 2322 and the first electrode lead 22 is a structure in which the solder mark area 2322 and the first electrode lead 22 are soldered from the side of the solder mark area 2322 away from the first electrode lead 22, such that the first solder mark 24 extends at least a portion from the first surface 23225 into the solder mark area 2322, then through the second surface 23226 and into the first electrode lead 22, so that the first solder mark 24 is connected to both the first surface 23225 and the second surface 23226, and such that in the projection plane perpendicular to the thickness direction X of the wall portion, the orthographic projection of the portion of the first solder mark 24 located in the electrode lead is located in the orthographic projection of the portion of the first solder mark 24 located in the solder mark area 2322.

[0197] It should be noted that the first solder mark 24 can be a structure that starts from the first surface 23225 and extends into the first electrode lead 22. Of course, the first solder mark 24 can also be a structure that partially protrudes from the first surface 23225.

[0198] In this embodiment, the first solder mark 24 is a structure in which at least part of the solder mark area 2322 extends from the surface of the solder mark area 2322 away from the first electrode lead 22 in the thickness direction X of the wall into the first electrode lead 22. This structure allows the soldering assembly between the solder mark area 2322 and the first electrode lead 22 to be performed from the side of the solder mark area 2322 away from the first electrode lead 22. Using this structure, the battery cell 20 can reduce the assembly difficulty between the first electrode lead 22 and the first tab 232, and improve the assembly efficiency of the first electrode lead 22 and the solder mark 232. On the one hand, it improves the welding quality between the printing areas 2322, and on the other hand, it facilitates the realization of the structure of the first solder printing part 24 as a solder printing area 2322 that is soldered through the entire first electrode tab 232 in the thickness direction X of the wall portion. This can increase the flow area between the first electrode tab 232 and the first electrode lead 22, thereby improving the flow effect between the first electrode tab 232 and the first electrode lead 22. It can also alleviate the phenomenon of local welding incompleteness of the first electrode tab 232 in the thickness direction X of the wall portion, thereby reducing the risk of unstable connection between the first electrode tab 232 and the first electrode lead 22.

[0199] According to some embodiments of this application, see Figure 4 and Figure 5 As shown, a first electrode lead-out member 22 is disposed on the wall portion 211. The first electrode lead-out member 22 has a connecting surface 2211 facing the solder area 2322 in the thickness direction X of the wall portion. The connecting surface 2211 abuts against the solder area 2322 and is soldered to the solder area 2322. In the thickness direction X of the wall portion, the root region 2321 extends beyond the connecting surface 2211 in the direction from the main body portion 231 to the wall portion 211.

[0200] In this embodiment, the connecting surface 2211 of the first electrode lead 22 is a surface that faces the solder area 2322 of the first electrode tab 232 in the thickness direction X of the wall portion and abuts against the solder area 2322. Correspondingly, the first solder portion 24 is a structure that partially passes through the connecting surface 2211 and extends into the first electrode lead 22. It should be noted that in the embodiment where at least a portion of the first solder portion 24 extends from the surface of the solder area 2322 away from the first electrode lead 22 into the first electrode lead 22, the first solder portion 24 is a structure that at least a portion extends from the first surface 23225 into the solder area 2322, and then sequentially passes through the second surface 23226 and the connecting surface 2211 and extends into the first electrode lead 22.

[0201] For example, the solder areas 2322 of the first electrode lead-out member 22 and the first electrode tab 232 are arranged along the thickness direction X of the wall portion, and the solder 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 portion 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 faces the main body portion 231 in the thickness direction X of the wall portion.

[0202] In the thickness direction X of the wall portion, the root region 2321 extends beyond the connecting surface 2211 in the direction from the main body portion 231 to the wall portion 211. That is, in the thickness direction X of the wall portion, the surface of the root region 2321 at the end or side furthest from the main body portion 231 is further away from the main body portion 231 than the connecting surface 2211. In other words, the root region 2321 of the first electrode tab 232 is a structure located partially on one side of the first electrode lead-out member 22 in the direction perpendicular to the thickness direction X of the wall portion.

[0203] In this embodiment, the first electrode lead 22 is disposed on the wall portion 211 of the outer casing 21, and the connecting surface 2211 of the first electrode lead 22 facing the solder area 2322 in the thickness direction X of the wall portion abuts against and is welded to the solder area 2322. This helps to reduce the assembly difficulty between the first electrode lead 22 and the solder area 2322, and also helps to improve the welding quality between the first electrode lead 22 and the solder area 2322. In particular, by setting the root region 2321 of the first tab 232 to be a structure in which the main body portion 231 points out of the connecting surface 2211 in the direction of the wall portion 211, the root region 2321 of the first tab 232 can also share space with the first electrode lead 22 in the thickness direction X of the wall portion, thereby improving the internal space utilization rate of the battery cell 20 and increasing the energy density of the battery cell 20.

[0204] According to some embodiments of this application, see Figure 4 , Figure 8 and Figure 9 As shown, the electrode assembly 23 can be a stacked structure. The electrode assembly 23 includes a plurality of first electrode plates 2311 and a plurality of second electrode plates 2312. The polarities of the first electrode plates 2311 and the second electrode plates 2312 are opposite. The first electrode plates 2311 and the second electrode plates 2312 are stacked and alternately arranged along the first direction Y. The first electrode tab 232 is connected to the plurality of first electrode plates 2311. The first direction Y is perpendicular to the thickness direction X of the wall portion.

[0205] The first tab 232 is connected to multiple first electrode pieces 2311. That is, each first electrode piece 2311 of the electrode assembly 23 is connected to the first tab 232. Correspondingly, the first tab 232 includes multiple tab pieces 232a stacked together, and each tab piece 232a of the first tab 232 is connected to a first electrode piece 2311, and each first electrode piece 2311 is connected to a tab piece 232a.

[0206] In this embodiment, the electrode assembly 23 is a stacked structure formed by alternating and stacking multiple first electrode sheets 2311 and multiple second electrode sheets 2312 along the first direction Y. The electrode assembly 23 with this structure can improve the volumetric energy density of the electrode assembly 23, thereby improving the energy density of the battery cell 20. In particular, by setting the first tab 232 to be a structure in which the density of the first region 23221 connected to the first soldering portion 24 from the root region 2321 to the soldering region 2322 is increased, the phenomenon of breakage or cracking of the first tab 232 due to local stress concentration during use can be alleviated. This can effectively alleviate the phenomenon of failure of some first electrode sheets 2311 or some second electrode sheets 2312 due to breakage or cracking of the first tab 232 during use, thereby reducing the risk of sudden drop in voltage or energy density of the battery cell 20 during use, and improving the performance and stability of the battery cell 20.

[0207] According to some embodiments of this application, see Figure 7 and Figure 8 As shown, the first tab 232 includes multiple tab pieces 232a stacked together. The multiple tab pieces 232a are welded together to form multiple solder grooves 23224 and a second solder part 2323 is formed at the corresponding position of the solder grooves 23224. The second solder part 2323 corresponds one-to-one with the solder grooves 23224 and is located at the bottom of the solder grooves 23224. The second solder part 2323 is only connected to the multiple tab pieces 232a.

[0208] In this process, multiple tabs 232a are welded together to form multiple solder grooves 23224, and second solder portions 2323 are formed at corresponding positions of the solder grooves 23224. That is, the solder grooves 23224 are groove structures formed by the multiple tabs 232a of the first tab 232 after pre-welding, and the multiple tabs 232a are welded together to form multiple second solder portions 2323. Correspondingly, each second solder portion 2323 is located at the bottom of a solder groove 23224, that is, at least a portion of each second solder portion 2323 forms at least a portion of the bottom wall of a solder groove 23224, so that the solder grooves 23224 and the second solder portions 2323 are arranged in a one-to-one correspondence in the thickness direction X of the wall.

[0209] The second soldering part 2323 only connects to multiple tabs 232a, that is, the second soldering part 2323 is a structure that only connects to multiple tabs 232a of the first tab 232. The second soldering part 2323 is not connected to other components, so that the second soldering part 2323 is a structure that is entirely located within the soldering area 2322 of the second tab 233. Of course, the second soldering part 2323 can also be a surface that partially protrudes from the side of the soldering area 2322 away from the soldering groove 23224. That is, the second soldering part 2323 can be a structure that is mostly located within the soldering area 2322 of the second tab 233 but partially protrudes from the second surface 23226 of the soldering area 2322.

[0210] In this embodiment, multiple tabs 232a of the first tab 232 are welded together to form multiple solder grooves 23224, and second solder portions 2323 are formed at the corresponding positions of the solder grooves 23224. The second solder portions 2323 are only connected to multiple tabs 232a, so that the solder grooves 23224 on the first tab 232 are structures formed by welding multiple tabs 232a stacked on the first tab 232 together. The second solder portion 2323 at the bottom of each solder groove 23224 is a structure formed by pre-welding multiple tabs 232a. The battery cell 20 with this structure can achieve the pre-welding and fixing of multiple tabs 232a of the first tab 232 before assembling the first tab 232 and the first electrode lead 22. On the one hand, it can reduce the phenomenon of multiple tabs 232a of the first tab 232 moving or shifting during the welding and assembly process with the first electrode lead 22, thereby reducing the impact on the first tab 232 and the first electrode lead 22. To address issues such as incomplete soldering or improper welding of the tabs 232a between the electrode leads 22, the assembly quality and current flow performance between the first tab 232 and the first electrode lead 22 are improved. Furthermore, since the sum of the areas of all solder grooves 23224 within a unit area of ​​the first region 23221 is greater than the sum of the areas of all solder grooves 23224 within a unit area of ​​the second region 23222, and the first region 23221 is connected to and surrounds the first solder section 24, the second region 23222 can also buffer stress during the welding and assembly process between the solder area 2322 and the first electrode lead 22. This reduces the risk of stress concentration at the edges of the first region 23221, which could cause cracking or breakage of some tabs 232a. Consequently, the risk of unstable or failed connections between the first electrode lead 22 and the electrode assembly 23 during use is further reduced, thereby improving the stability and lifespan of the battery cell 20.

[0211] According to some embodiments of this application, this application also provides a battery device 100, which includes a battery cell 20 of any of the above schemes.

[0212] Among them, see Figure 2 As shown, the battery device 100 may also include a housing 10, in which the battery cells 20 are housed.

[0213] In some embodiments, the housing 10 may include a first housing body 11 and a second housing body 12, the first housing body 11 and the second housing body 12 covering each other, the first housing body 11 and the second housing body 12 together defining an assembly space for accommodating the battery cell 20.

[0214] Optionally, the second box body 12 can be a hollow structure with one end open, and the first box body 11 can be a plate-like structure. The first box body 11 covers the open side of the second box body 12 so that the first box body 11 and the second box body 12 together define the assembly space; the first box body 11 and the second box body 12 can also be hollow structures with one side open, and the open side of the first box body 11 covers the open side of the second box body 12.

[0215] Of course, the box 10 formed by the first box body 11 and the second box body 12 can be of various shapes, such as a cylinder or a cuboid. For example, in... Figure 2 In the middle, box 10 has a rectangular structure.

[0216] Optionally, the battery cell 20 disposed within the housing 10 can be one or more. For example, in... Figure 2 In the battery device 100, multiple battery cells 20 are arranged inside the housing 10. The multiple battery cells 20 can be connected in series, parallel, or in a mixed manner. A mixed connection means that the multiple battery cells 20 are connected in both series and parallel. The multiple battery cells 20 can be directly connected in series, parallel, or in a mixed manner, and then the whole assembly of the multiple battery cells 20 is housed in the housing 10. Of course, the battery device 100 can also be formed by first connecting multiple battery cells 20 in series, parallel, or in a mixed manner to form a battery module, and then connecting multiple battery modules in series, parallel, or in a mixed manner to form a whole assembly, which is also housed in the housing 10.

[0217] The battery device 100 may also include other structures. For example, the battery device 100 may also include a busbar component that connects multiple battery cells 20 to achieve electrical connection between the multiple battery cells 20.

[0218] It should be noted that in some embodiments, the battery device 100 may not have a housing 10. The battery device 100 includes multiple battery cells 20, and the battery device 100 composed of multiple battery cells 20 can be directly mounted onto the electrical device to provide power to the electrical device through the multiple battery cells 20. That is, the housing 10 can be part of the electrical device. Taking a vehicle 1000 as an example, the housing 10 can be part of the chassis structure of the vehicle 1000. For example, a portion of the housing 10 can be at least a part of the floor of the vehicle 1000, or a portion of the housing 10 can be at least a part of the crossbeams and longitudinal beams of the vehicle 1000.

[0219] According to some embodiments of this application, this application also provides an electrical device, which includes a battery cell 20 of any of the above schemes, and the battery cell 20 is used to provide electrical energy to the electrical device.

[0220] The electrical device can be any of the aforementioned devices or systems that utilize battery cells 20.

[0221] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0222] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A battery cell, characterized in that, include: The outer shell has walls; A first electrode lead-out is disposed on the outer casing; as well as At least one electrode assembly is disposed within the housing, the electrode assembly including a main body and a first electrode tab, the first electrode tab being connected to the end of the main body facing the wall portion; The first electrode tab includes a root region and a solder area that are connected to each other. The root region is connected to the main body. The solder area includes a first region and a second region. The first region is connected to the root region through the second region. The solder area has a plurality of solder grooves formed on the surface of one side of the wall in the thickness direction. The sum of the areas of all the solder grooves in the first region per unit area is greater than the sum of the areas of all the solder grooves in the second region per unit area. The solder area is welded to the first electrode lead to form a first solder part, and the first region is connected to and surrounds the outside of the first solder part. The root region and the solder area are arranged and connected along the extension direction of the first electrode tab. The main body has a flat region, which 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 near the wall in the thickness direction of the wall. The first electrode tab has two opposing first edges in a second direction. The thickness direction of the wall, the first direction, and the second direction are perpendicular to each other. The second region is adjacent to the root region. The plurality of solder grooves in the second region adjacent to the root region are arranged along a preset trajectory line. The preset trajectory line includes a straight line segment and two arc segments. The straight line segment transitions to the two first edges through the two arc segments respectively.

2. The battery cell according to claim 1, characterized in that, The thickness of the portion of the first region without the solder groove is equal to the thickness of the portion of the second region without the solder groove.

3. The battery cell according to claim 1, characterized in that, The first region accounts for 50%-80% of the sum of the areas of all the solder grooves within a unit area.

4. The battery cell according to claim 1, characterized in that, The second zone accounts for 20%-60% of the sum of the areas of all the solder grooves within a unit area.

5. The battery cell according to claim 1, characterized in that, The second region surrounds the outside of the first region.

6. The battery cell according to claim 1, characterized in that, The solder area has a first surface and a second surface opposite each other in the thickness direction of the wall portion. The first surface is formed with a plurality of solder grooves. Along the thickness direction of the wall portion, the second surface faces and abuts against the first electrode lead-out, and the first solder 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 1-7, characterized in that, The solder area further includes at least one third area, through which the first area and the second area are connected; Wherein, the sum of the areas of all the solder grooves in the third region within a unit area is greater than the sum of the areas of all the solder grooves in the second region within a unit area, and the sum of the areas of all the solder grooves in the third region within a unit area is less than the sum of the areas of all the solder grooves in the first region within a unit area.

9. The battery cell according to claim 8, characterized in that, The solder area includes a plurality of third areas, which are connected sequentially between the first area and the second area along the direction from the first area to the second area; In each pair of adjacent third zones, the sum of the areas of all solder grooves in a unit area of ​​the third zone closer to the first zone is greater than the sum of the areas of all solder grooves in a unit area of ​​the third zone closer to the second zone.

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

11. The battery cell according to any one of claims 1-7, characterized in that, The first electrode lead-out is an electrode terminal disposed on the wall portion, and the electrode terminal is welded to the solder area to form the first solder area.

12. The battery cell according to claim 11, characterized in that, The solder area and the first electrode lead 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 solder mark extends from the surface of the solder mark area on the side opposite to the first electrode lead into the first electrode lead.

13. The battery cell according to any one of claims 1-7, characterized in that, The first electrode lead is disposed on the wall portion, and the first electrode lead has a connecting surface facing the solder area in the thickness direction of the wall portion. The connecting surface abuts against the solder area and is welded to the solder area. Wherein, in the thickness direction of the wall portion, the root region extends beyond the connecting surface along the direction from the main body portion toward the wall portion.

14. The battery cell according to any one of claims 1-7, characterized in that, The electrode assembly has a stacked structure, comprising a plurality of first electrodes and a plurality of second electrodes. The first electrodes and the second electrodes have opposite polarities. The first electrodes and the second electrodes are stacked and alternately arranged along a first direction, and the first electrode tab is connected to the plurality of first electrodes. The first direction is perpendicular to the thickness direction of the wall portion.

15. The battery cell according to any one of claims 1-7, characterized in that, The first electrode tab includes multiple electrode tabs stacked together. The multiple electrode tabs are welded together to form multiple solder grooves and a second solder part is formed at the position corresponding to the solder groove. The second solder part corresponds one-to-one with the solder groove and is located at the bottom of the solder groove. The second solder part is only connected to the multiple electrode tabs.

16. A battery device, characterized in that, Includes the battery cell as described in any one of claims 1-15.

17. An electrical device, characterized in that, Includes a battery cell as described in any one of claims 1-15, the battery cell being used to provide electrical energy.

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