Electrode assembly and method of manufacturing the same, battery cell, battery, and electric device

Abstract

The application discloses an electrode assembly and a preparation method thereof, a battery monomer, a battery and a power utilization device. The electrode assembly comprises an active material coating part and a tab part. The tab part comprises a plurality of tab pieces stacked together. The plurality of tab pieces have an overlapping area and a misaligned area after being stacked. The overlapping area is welded to form a first welding part. The misaligned area is welded to form a second welding part at least at a position away from the active material coating part. In the technical scheme of the application, on the one hand, the utilization rate of the tab part is improved, which is conducive to improving the capacity of the battery monomer, reducing the overcurrent temperature rise. On the other hand, compared with the fluffy plurality of tab pieces, the second welding part can support the welding pressure nozzle, reduce the welding defect problem, reduce the cutting requirement of the welded tab part, save the cost, improve the fast charging performance and assembly efficiency of the battery monomer, and also make the tab part not easy to be scratched by the hole wall of the through hole structure.

Description

Technical Field

[0001] This application relates to the field of batteries, specifically to an electrode assembly and its preparation method, a battery cell, a battery, and an electrical device. Background Technology

[0002] Energy conservation and emission reduction are key to the sustainable development of the automotive industry, and electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of this sustainable development. For electric vehicles, battery technology is a crucial factor in their development. Low utilization rates of the tabs in the electrode components of related technologies lead to reduced capacity in individual battery cells. Summary of the Invention

[0003] In view of the above problems, this application provides an electrode assembly and its preparation method, a battery cell, a battery, and an electrical device, which can improve the utilization rate of the electrode tabs of the electrode assembly and increase the capacity of the battery cell.

[0004] In a first aspect, this application provides an electrode assembly, comprising: an active material coating portion; and an electrode tab portion connected to the active material coating portion, wherein the electrode tab portion includes a plurality of stacked electrode tabs, the plurality of electrode tabs having an overlapping region and a misaligned region after being stacked, the overlapping region being welded to form a first weld portion, and the misaligned region being welded at least at a position away from the active material coating portion to form a second weld portion.

[0005] In the technical solution of this application embodiment, by welding the overlapping areas of multiple tabs to form a first welded portion, and welding the misaligned areas of the multiple tabs away from the active material coating to form a second welded portion, the area of ​​the welding region of the multiple tabs can be increased. On the one hand, this improves the utilization rate of the tabs, which is beneficial to increasing the capacity of the battery cell and reducing overcurrent temperature rise. On the other hand, when welding the tabs to the terminals, the second welded portion, compared to the loose multiple tabs, can better support the welding nozzle and avoid wrinkles and other problems. This reduces the welding defects caused by the welding nozzle pressing onto the loose areas of the multiple tabs in related technologies, reduces the cutting requirements of the welded tabs, saves costs, and improves the fast charging performance of the battery cell. In addition, by welding the misaligned areas to form the second welded portion, the efficiency of the tabs passing through the through-hole structure can be improved, thereby improving the assembly efficiency of the battery cell and making the tabs less susceptible to scratches from the hole walls of the through-hole structure.

[0006] In some embodiments, the first welding portion and the second welding portion are connected. In the above technical solution, compared with the multiple loose electrode tabs, the connected first welding portion and the second welding portion can, on the one hand, improve the rigidity of the multiple electrode tabs after welding to a certain extent, making the electrode tabs less likely to be scratched by the hole wall of the through hole structure, and improving the efficiency of the electrode tabs passing through the through hole structure. On the other hand, the second welding portion formed after welding is less likely to collapse under pressure compared with the first welding portion, which can effectively support the welding nozzle and prevent wrinkles and other problems. This can reduce the welding defects caused by the welding nozzle pressing onto the loose area of ​​the multiple electrode tabs in the related technology.

[0007] In some embodiments, along the width direction of the tab, the ratio of the width dimension of the first welded portion to the width dimension of the second welded portion ranges from 0.8 to 1.2; and / or, along the width direction of the tab, the ratio of the width dimension of the first welded portion to the width dimension of the tab ranges from 0.6 to 1; along the height direction of the tab, the ratio of the height dimension of the second welded portion to the height dimension of the first welded portion is 0.08 to 0.2; and / or, along the height direction of the tab, the ratio of the height dimension of the first welded portion to the height dimension of the tab is 0.45 to 0.65. In the above technical solution, the area of ​​the welding region of multiple tabs can be increased, improving the utilization rate of the tab, which is beneficial to increasing the capacity of the battery cell, reducing overcurrent temperature rise, and also reducing welding defects caused by the welding nozzle pressing onto the loose area of ​​multiple tabs in related technologies.

[0008] In some embodiments, the height dimension of the second welded portion along the height direction of the tab is 1mm-2mm. In the above technical solution, by limiting the height dimension of the second welded portion to meet the above conditions, on the one hand, the proportion of misaligned areas of multiple tabs can be reduced as much as possible, improving the pass rate of the electrode assembly and thus improving the quality of the battery cell. On the other hand, based on the misalignment of multiple tabs, welding the misaligned areas can increase the area of ​​the welding region of multiple tabs, reducing the welding defects caused by the welding nozzle pressing onto the loose areas of multiple tabs in related technologies.

[0009] In some embodiments, the thickness of the second welded portion gradually decreases in the direction away from the first welded portion, making it easier to cut.

[0010] In some embodiments, the second weld portion has two opposing first surfaces and a second surface, at least one of which is inclined relative to the height direction of the tab portion. In the above technical solution, forming the second weld portion in this form facilitates subsequent decision-making regarding whether to cut it as needed, improving the convenience of cutting.

[0011] In some embodiments, the maximum distance between the first surface and the second surface is 0.5mm-1mm. In the above technical solution, by limiting the maximum distance between the first surface and the second surface to meet the above range, it is easier to decide whether to cut as needed, improving the convenience of cutting; on the other hand, it can reduce welding difficulty, reduce welding defects, and improve welding quality.

[0012] In some embodiments, the first surface extends along the height direction of the tab, and the second surface is inclined relative to the height direction of the tab, with the distance between the first surface and the second surface gradually decreasing in the direction away from the first weld portion. In the above technical solution, forming the second weld portion in this manner facilitates subsequent decisions on whether to cut it as needed, improving cutting convenience; on the other hand, it reduces welding difficulty, minimizes welding defects, and improves welding quality.

[0013] In some embodiments, the included angle between the first surface and the second surface is 10°-45°. This facilitates welding of the portion of the misaligned area far from the active material coating using an ultrasonic welding mount and ultrasonic welding head, improving welding convenience and quality.

[0014] In some embodiments, the first welded portion and the second welded portion are formed by ultrasonic welding, which can improve welding speed and efficiency, improve the surface quality after welding, and the welding process is clean, stable, and reliable with low energy consumption.

[0015] In some embodiments, the misaligned region is welded to at least one side of the overlapping region to form a third welded portion. In the above technical solution, by welding the misaligned region to at least one side of the overlapping region to form a third welded portion, the area of ​​the welding region for multiple tabs can be increased, improving the utilization rate of the tabs and thus increasing the capacity of the battery cell and reducing overcurrent temperature rise. Furthermore, it can reduce welding defects caused by the welding nozzle pressing onto the loose area of ​​multiple tabs in related technologies, and also facilitates the tabs passing through the perforations on the electrode post.

[0016] Secondly, this application provides a battery cell, the battery cell comprising: a housing, the housing having a terminal post; an electrode assembly disposed within the housing, the electrode tab being connected to the terminal post, the electrode assembly being the electrode assembly described in any of the above embodiments.

[0017] In the technical solution of this application embodiment, by adopting the above-mentioned electrode assembly, on the one hand, the utilization rate of the tab is improved, which is conducive to increasing the capacity of the battery cell and reducing the overcurrent temperature rise. On the other hand, when welding the tab to the terminal post, the second welding part can better support the welding nozzle compared to the multiple loose tabs, and will not cause problems such as wrinkles. This reduces the welding defects caused by the welding nozzle pressing onto the loose area of ​​multiple tabs in related technologies, thereby improving the reliability of the battery cell, reducing the cutting requirements of the welded tab, thereby reducing the production difficulty of the battery cell, saving costs, and improving the fast charging performance of the battery cell.

[0018] In some embodiments, the terminal post is provided with a receiving portion, and at least a portion of the tab extends into the receiving portion and is welded to the terminal post. The hollow structure of the receiving portion can, on the one hand, reduce the weight of the terminal post to a certain extent, thereby increasing the weight energy density of the battery cell and the battery. On the other hand, the tab can be accommodated in the receiving portion, improving the assembly efficiency of the tab and saving the space occupied by the tab. This makes full use of the space of the battery cell, resulting in a tighter and more reliable fit between the support and the terminal post, and between the support and the tab. This makes the structure of the battery cell more compact and more conducive to improving the energy density of the battery cell.

[0019] In some embodiments, the receiving portion includes a first receiving groove, the surface of the electrode post facing the active material coating portion is the inner end face of the electrode post, the opening of the first receiving groove is formed on the inner end face of the electrode post, and at least a portion of the tab is received within the first receiving groove. In the above technical solution, on the one hand, opening the first receiving groove on the electrode post can reduce the weight of the electrode post to a certain extent, thereby increasing the gravimetric energy density of the battery cell and the battery; on the other hand, since the opening of the first receiving groove is formed on the inner end face of the electrode post, and the inner end face of the electrode post is the surface of the electrode post near the active material coating portion, the first receiving groove can open towards the active material coating portion, thus facilitating the tab to extend into the first receiving groove and improving assembly efficiency. Moreover, this type of first receiving groove is easy to process, improving production efficiency.

[0020] In some embodiments, the receiving portion includes a second receiving groove, the surface of the electrode post away from the active material coating portion is the outer end face of the electrode post, the opening of the second receiving groove is formed on the outer end face of the electrode post, the second receiving groove communicates with the interior of the housing through a perforation, and the tab portion passes through the perforation and is at least partially received in the second receiving groove. In the above technical solution, on the one hand, the electrode post is provided with a second receiving groove, which can reduce the weight of the electrode post to a certain extent, thereby improving the weight energy density of the battery cell and the battery; on the other hand, since the opening of the second receiving groove is formed on the outer end face of the electrode post, and the outer end face of the electrode post is the surface of the electrode post away from the active material coating portion, the second receiving groove can be opened in the direction away from the active material coating portion. In this way, when at least part of the tab portion is received in the second receiving groove, the tab portion can be easily stored and organized through the opening of the second receiving groove, and the electrical connection operation between the tab portion and the electrode post can be easily performed through the opening of the second receiving groove, thereby reducing the production difficulty of the battery cell and improving the production efficiency of the battery cell.

[0021] In some embodiments, the housing includes a cover and a body with an opening, the cover closing onto the opening, and the electrode post being provided on the wall of the cover and / or the body opposite the opening. Placing the electrode post on the cover allows for a smaller mold or fixture size, thus reducing costs; placing the electrode post on the wall of the body opposite the opening allows the electrode assembly to enter the body through the opening, with the tab directly opposite the electrode post, facilitating easier connection between the tab and the electrode post and improving the assembly efficiency of the battery cell.

[0022] Thirdly, this application provides a battery, which includes the battery cell described in any of the above embodiments.

[0023] In the technical solution of this application embodiment, by using the above-mentioned battery cell, it is beneficial to increase the battery capacity, improve the reliability of battery use, and reduce the difficulty of production.

[0024] Fourthly, this application provides an electrical device including the battery described in any of the above embodiments.

[0025] In the technical solution of this application embodiment, by using the above-mentioned battery, the reliability of the electrical device can be improved.

[0026] Fifthly, this application provides a method for preparing an electrode assembly, comprising the following steps: providing an incoming material for the electrode assembly; stacking multiple tabs of the electrode assembly; welding the overlapping areas of the multiple tabs to form a first welding portion of the tab; welding the misaligned areas of the multiple tabs to form a second welding portion of the tab, wherein the second welding portion is located at the end of the first welding portion away from the active material coating portion.

[0027] In the technical solution of this application embodiment, by welding the overlapping areas of multiple tabs to form a first welding part, and welding the misaligned areas of multiple tabs away from the active material coating to form a second welding part, the area of ​​the welding region of multiple tabs can be increased. On the one hand, this improves the utilization rate of the tabs, which is beneficial to increasing the capacity of the battery cell and reducing overcurrent temperature rise. On the other hand, when welding the tabs to the terminals, the second welding part can better support the welding nozzle compared to the loose multiple tabs, reducing the welding defects caused by the welding nozzle pressing onto the loose area of ​​the multiple tabs in related technologies. This also reduces the cutting requirements of the welded tabs, saves costs, and improves the fast charging performance of the battery cell.

[0028] In some embodiments, welding the overlapping areas of the plurality of electrode tabs includes: sandwiching the overlapping areas of the plurality of electrode tabs between a first ultrasonic welding base and a first ultrasonic welding head, so as to weld the overlapping areas of the electrode tabs to form the first welded portion using ultrasonic welding. In the above technical solution, since the first welded portion is formed by ultrasonic welding, the welding speed and welding efficiency can be improved, the surface quality of the overlapping area after welding can be improved, the welding process is clean, stable, and reliable, and the energy consumption is low.

[0029] In some embodiments, welding the misaligned areas of the plurality of electrode tabs includes: sandwiching the misaligned areas of the plurality of electrode tabs between a second ultrasonic welding base and a second ultrasonic welding head, thereby welding the misaligned areas of the electrode tabs to form the second welded portion using ultrasonic welding. In the above technical solution, since the second welded portion is formed using ultrasonic welding, welding speed and efficiency can be improved, the surface quality of the overlapping area after welding can be improved, the welding process is clean, stable, and reliable, and energy consumption is low.

[0030] In some embodiments, one of the surfaces of the second ultrasonic welding base and the second ultrasonic welding head extends along the height of the tab and the other is inclined relative to the height direction of the tab. In the above technical solution, by employing the second ultrasonic welding base and the second ultrasonic welding head, ultrasonic welding can be performed on misaligned areas to form a pre-defined second welded portion. This facilitates subsequent decisions on whether to cut as needed, improving the convenience of cutting, and also reduces welding difficulty, minimizes welding defects, and improves welding quality.

[0031] In some embodiments, the angle between the surfaces of the second ultrasonic welding base and the second ultrasonic welding head facing each other is smaller than the angle between the two opposing wall surfaces of the misaligned region. This arrangement allows the second ultrasonic welding base and the second ultrasonic welding head to clamp the portion of the misaligned region away from the active material coating, thereby improving welding quality.

[0032] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0033] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0034] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments;

[0035] Figure 2 Exploded views of the battery structure provided in some embodiments of this application;

[0036] Figure 3 A perspective view of a battery cell provided in some embodiments of this application;

[0037] Figure 4 These are structural cross-sectional views of a battery cell provided in some embodiments of this application;

[0038] Figure 5 Partial enlarged views of electrode assemblies provided in some embodiments of this application;

[0039] Figure 6 Side view of an electrode assembly provided in some embodiments of this application;

[0040] Figure 7 for Figure 6 A partial enlarged view of the electrode assembly shown;

[0041] Figure 8 A schematic diagram of the electrode tab portion of an electrode assembly provided in some embodiments of this application before mating;

[0042] Figure 9 A schematic diagram of the structure of the electrode tab of the electrode assembly provided in some embodiments of this application after mating with the first ultrasonic welding base and the first ultrasonic welding head;

[0043] Figure 10 A schematic diagram of the structure of the overlapping area of ​​the electrode tab of the electrode assembly provided in some embodiments of this application before welding, together with the first ultrasonic welding seat and the first ultrasonic welding head.

[0044] Figure 11 This is a schematic diagram of the structure of an electrode assembly provided in some embodiments of this application, wherein the overlapping area of ​​the electrode tabs is formed into a first welded part by ultrasonic welding;

[0045] Figure 12 A schematic diagram of the structure of the misaligned area of ​​the electrode tab of the electrode assembly provided in some embodiments of this application before welding, together with the second ultrasonic welding seat and the second ultrasonic welding head.

[0046] Figure 13 This is a schematic diagram of the structure of an electrode assembly provided in some embodiments of this application, wherein the misaligned area of ​​the tab that is away from the active material coating is formed into a second welded part by ultrasonic welding.

[0047] Figure 14 This is a schematic diagram of the structure of an electrode assembly provided in some embodiments of this application;

[0048] Figure 15 Partial enlarged view of the electrode assembly provided for other embodiments of this application;

[0049] Figure 16 Top view of an electrode assembly provided for other embodiments of this application;

[0050] Figure 17 A cross-sectional schematic diagram of the tab portion of an electrode assembly provided in some embodiments of this application;

[0051] Figure 18 A partial cross-sectional schematic diagram of a battery cell provided in some embodiments of this application;

[0052] Figure 19 A partial cross-sectional schematic diagram of a battery cell provided in some embodiments of this application;

[0053] Figure 20 A partial cross-sectional schematic diagram of a battery cell provided in some embodiments of this application;

[0054] Figure 21 A partial cross-sectional schematic diagram of a battery cell provided in some embodiments of this application;

[0055] Figure 22 A partial cross-sectional schematic diagram of a battery cell provided in some embodiments of this application;

[0056] Figure 23 A partial cross-sectional schematic diagram of a battery cell provided in some embodiments of this application;

[0057] Figure 24 This is a flowchart illustrating the fabrication process of electrode assemblies provided in some embodiments of this application.

[0058] The reference numerals in the detailed embodiments are as follows:

[0059] Electrical device 1000, battery 100, controller 200, motor 300

[0060] First direction Z, second direction X, third direction Y, pole axis R.

[0061] 10 battery cells, 20 casings, first casing 201, second casing 202.

[0062] 11 housing, 111 housing body, 1110 opening, 112 housing cover, 113 mounting hole.

[0063] The components include: a pole post 12, a receiving portion 121, a first receiving groove 12110, a first end wall 12111, a first recessed groove 12112, a first side wall 12113, a second receiving groove 12120, a second end wall 12121, a second recessed groove 12122, a second side wall 12123, a through hole 12130, an inner end face 122 of the pole post, an outer end face 123 of the pole post, a first groove 126, a spacer portion 127, a cover plate 13; a first conductive element 131; a second groove 1311; and a second conductive element 132.

[0064] Electrode assembly 2, active material coating portion 21, tab portion 22, tab plate 221, overlapping area Z1, misaligned area Z2, end misaligned area Z21, side misaligned area Z22, first welding portion 2211, second welding portion 2212, third welding portion 2213, first surface 2214, second surface 2215.

[0065] 3. Bracket; 314 through hole; 4. Insulating component; 6. Explosion-proof valve; 7. Slot cover.

[0066] First ultrasonic welding socket 81, first ultrasonic welding head 82, second ultrasonic welding socket 91, second ultrasonic welding head 92. Detailed Implementation

[0067] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0068] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein 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 specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0069] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0070] In this document, the term "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 throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0071] In the description of the embodiments 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, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0072] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0073] In the description of the embodiments of this application, the technical terms "center," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0074] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0075] Currently, judging from market trends, the application of power batteries is becoming increasingly widespread. Power batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. With the continuous expansion of power battery applications, market demand is also constantly increasing.

[0076] In related technologies, the electrode assembly of a battery cell includes multiple layers of tabs stacked together. These multiple layers of tabs are connected to form tabs by ultrasonic welding. However, due to processing and tolerance issues, the multiple layers of tabs cannot completely overlap, resulting in misalignment.

[0077] Generally, during the assembly of a battery cell, the tabs need to be passed through a through-hole structure first, and then welded to the terminal post. This through-hole structure can be a through-hole structure on the terminal post or a through-hole structure on the bracket located between the terminal post and the electrode assembly. The misaligned tabs are relatively loose, and during the process of passing through the through-hole structure, they are prone to interference with the hole wall of the through-hole structure. This not only affects the assembly efficiency of the battery cell, but also easily scratches the tabs. Therefore, before welding the tabs to the terminal post, the tabs need to be cut off to remove the misaligned parts, and then the welding nozzle is pressed onto the welding position of the tab. Otherwise, if the welding nozzle is pressed onto the loose area of ​​the tab, welding defects will occur.

[0078] Furthermore, because the misaligned portion needs to be cut off before the tab is connected to the terminal post, the overall length of the tab is shortened and its utilization rate is reduced. When the tab is welded to the terminal post, the required welding nozzle size is smaller, the weld length formed by the tab and the terminal post is smaller, the current flow area is smaller, and the current flow efficiency is lower, which affects the charging and discharging efficiency of the battery cell and leads to a reduction in the capacity of the battery cell.

[0079] Therefore, embodiments of this application propose an electrode assembly in which overlapping areas of multiple tabs are welded to form a first welded portion, and misaligned areas of multiple tabs away from the active material coating are welded to form a second welded portion. This increases the area of ​​the welding region of the multiple tabs, improving the utilization rate of the tabs, which is beneficial to increasing the capacity of the battery cell and reducing overcurrent temperature rise. Furthermore, when welding the tabs to the terminals, the second welded portion can better support the welding nozzle compared to the loose tabs, reducing welding defects caused by the welding nozzle pressing onto the loose areas of the tabs in related technologies. This also reduces the cutting requirements of the welded tabs, saves costs, and improves the fast-charging performance of the battery cell.

[0080] The electrode assembly disclosed in this application is used in a battery cell, which can be used in electrical devices that use batteries as a power source or in various energy storage systems that use batteries as energy storage elements. Electrical devices can be, but are 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.

[0081] For ease of explanation, the following embodiments will be described using a vehicle as an example of an electrical device 1000 according to an embodiment of this application.

[0082] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle provided in some embodiments of this application. The vehicle 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 100 is installed inside the vehicle, and the battery 100 can be located at the bottom, front, or rear of the vehicle. The battery 100 can be used to power the vehicle; for example, the battery 100 can serve as the vehicle's operating power source. The vehicle may also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle during starting, navigation, and driving.

[0083] In some embodiments of this application, the battery 100 can not only serve as the operating power source for the vehicle, but also as the driving power source for the vehicle, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle.

[0084] Please refer to Figure 2 , Figure 2 This is an exploded view of a battery 100 provided in some embodiments of this application. The battery 100 includes a housing 20 and a battery cell 10, with the battery cell 10 housed within the housing 20. The housing 20 provides a space for the battery cell 10 and can have various structures. In some embodiments, the housing 20 may include a first housing 201 and a second housing 202, which overlap each other, together defining a space for accommodating the battery cell 10. The second housing 202 may be a hollow structure with an opening 1110 at one end, while the first housing 201 may be a plate-like structure, covering the opening side of the second housing 202 so that the first housing 201 and the second housing 202 together define the space. Alternatively, both the first housing 201 and the second housing 202 may be hollow structures with openings on one side, with the opening side of the first housing 201 covering the opening side of the second housing 202. Of course, the box 20 formed by the first box 201 and the second box 202 can be of various shapes, such as a cylinder, a cuboid, etc.

[0085] In battery 100, there can be multiple battery cells 10, which can be connected in series, parallel, or in a mixed manner. A mixed connection means that multiple battery cells 10 are connected in both series and parallel configurations. Multiple battery cells 10 can be directly connected in series, parallel, or in a mixed manner, and then the entire assembly of the multiple battery cells 10 is housed within the housing 20. Alternatively, battery 100 can also be composed of multiple battery cells 10 first connected in series, parallel, or in a mixed manner to form battery modules, and then these modules are connected in series, parallel, or in a mixed manner to form a whole, which is also housed within the housing 20. Battery 100 may also include other structures; for example, it may include a busbar component for electrical connection between the multiple battery cells 10.

[0086] Each battery cell 10 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 10 can be cylindrical, flat, cuboid, or other shapes.

[0087] Please refer to Figure 3 and Figure 4 , Figure 3 A perspective view of a battery cell 10 provided in some embodiments of this application; Figure 4This is a structural cross-sectional view of a battery cell 10 provided in some embodiments of this application. The battery cell 10 refers to the smallest unit that makes up the battery 100. For example... Figure 3 and Figure 4 The battery cell 10 includes a housing 11 and an electrode assembly 2. The housing 11 includes a cover 112 and a body 111.

[0088] The housing 111 has an opening 1110, and the cover 112 is a component that closes onto the opening 1110 to isolate the internal environment of the battery cell 10 from the external environment. The shape of the cover 112 can be adapted to the shape of the housing 111 to fit it. Optionally, the cover 112 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the cover 112 is less prone to deformation under pressure and impact, allowing the battery cell 10 to have higher structural strength and improved reliability. Functional components such as electrode terminals can be provided on the cover 112. The electrode terminals can be used to electrically connect to the electrode assembly 2 for outputting or inputting electrical energy into the battery cell 10. In some embodiments, the cover 112 can also be provided with a pressure relief mechanism for releasing internal pressure when the internal pressure or temperature of the battery cell 10 reaches a threshold. The material of the cover 112 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose any special limitations on this. In some embodiments, an insulating element may be provided on the inner side of the cover 112. The insulating element can be used to isolate the electrical connection components inside the housing 111 from the cover 112 to reduce the risk of short circuit. Exemplarily, the insulating element may be plastic, rubber, etc.

[0089] The housing 111 is a component used to cooperate with the cover 112 to form the internal environment of the battery cell 10. This internal environment can accommodate the electrode assembly 2, electrolyte, and other components. The housing 111 and cover 112 can be independent components. An opening 1110 can be provided on the housing 111, and the cover 112 can close the opening 1110 to form the internal environment of the battery cell 10. Alternatively, the cover 112 and housing 111 can be integrated. Specifically, the cover 112 and housing 111 can form a common connecting surface before other components are inserted into the housing. When it is necessary to encapsulate the interior of the housing 111, the cover 112 closes the housing 111. The housing 111 can have various shapes and sizes, such as cuboid, cylindrical, or hexagonal prism. Specifically, the shape of the housing 111 can be determined according to the specific shape and size of the electrode assembly 2. The shell 111 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. This application embodiment does not impose any special restrictions on this.

[0090] The casing 111 may contain one or more electrode assemblies 2. The electrode assembly 2 is the component in the battery cell 10 where the electrochemical reaction occurs. The electrode assembly 2 includes an active material coating portion 21 and a tab portion 22, with the tab portion 22 connected to the active material coating portion 21. The electrode assembly 2 is mainly formed by winding or stacking positive and negative electrode sheets, and a separator is typically provided between the positive and negative electrode sheets. The portions of the positive and negative electrode sheets with active material constitute the active material coating portion 21 of the electrode assembly 2, while the portions of the positive and negative electrode sheets without active material each constitute the tab portion 22. During the charging and discharging process of the battery 100, the positive and negative active materials react with the electrolyte, and the tab portion 22 connects to the electrode terminals to form a current loop.

[0091] Electrode assembly 2 is the component in the battery cell 10 where the electrochemical reaction occurs. The casing 11 may contain one or more electrode assemblies 2. Electrode assembly 2 includes an active material coating portion 21 and tabs 22 connected to the active material coating portion 21. Specifically, electrode assembly 2 is mainly formed by winding or stacking a positive electrode sheet, a separator, and a negative electrode sheet. The portions of the positive and negative electrode sheets with active material constitute the active material coating portion 21 of electrode assembly 2, and the portions of the positive and negative electrode sheets without active material each constitute the tabs 22. The positive and negative tabs may be located together at one end of the active material coating portion 21 or at opposite ends of the active material coating portion 21. During the charging and discharging process of the battery 100, the positive and negative active materials react with the electrolyte, and the tabs 22 connect to electrode terminals (e.g., terminals) to form a current loop.

[0092] like Figure 3 and Figure 4 The battery cell 10 also includes a support 3, an insulator 4, and an explosion-proof valve 6. The support 3 is located at one end of the active material coating portion 21, and has a through hole 314. The electrode tab 22 passes through the through hole 314 to connect with the electrode post 12. The insulator 4 is connected to the support 3 and together they wrap around the circumference of the electrode assembly 2. The insulator 4 can be used to isolate the electrical connection components inside the housing 11 from the housing 11 to reduce the risk of short circuit. For example, the insulator 4 can be made of plastic, rubber, etc. The insulator 4 and the support 3 can be bonded together, or they can be heat-fused together. Of course, the insulator 4 and the support 3 can also be connected in other ways. The explosion-proof valve 6 is located on the housing 11 and is used to release internal pressure when the internal pressure or temperature of the battery cell 10 reaches a threshold. The explosion-proof valve 6 can be located on the cover 112 or on any wall of the housing 111.

[0093] Based on some embodiments of this application, please continue to refer to Figure 4 and further refer to Figure 5 , Figure 5This is a partial enlarged view of the electrode assembly 2 provided in some embodiments of this application. The electrode tab 22 of the electrode assembly 2 includes multiple stacked tabs 221. Due to factors such as manufacturing method and manufacturing tolerance, it is difficult to strictly align the multiple layers of tabs 221 after stacking, resulting in edge misalignment. Therefore, on the projection plane perpendicular to the thickness direction of the tabs 221, the area where the projections of the multiple layers of tabs 221 completely overlap is defined as the overlapping area Z1, and the area where the projections of the multiple layers of tabs 221 do not completely overlap is defined as the misalignment area Z2. That is, the stacked multiple tabs 221 have both the overlapping area Z1 and the misalignment area Z2. The reason for the occurrence of the misalignment area Z2 is that the electrode assembly 2 is formed by winding or stacking positive electrode sheets and separator negative electrode sheets. During the winding or stacking process of the electrode assembly 2, due to manufacturing errors, the tabs 211 corresponding to each layer of positive or negative electrode sheets cannot be completely aligned.

[0094] Please refer to further details. Figure 6 and Figure 7 , Figure 6 A side view of electrode assembly 2 provided in some embodiments of this application; Figure 7 for Figure 6 The diagram shows a partial enlarged view of the electrode assembly 2. A first weld portion 2211 is formed by welding the overlapping region Z1, thereby welding multiple tabs 221 together at the position of the overlapping region Z1. A second weld portion 2212 is formed by welding the misaligned region Z2 at least at a position away from the active material coating portion 21, thereby welding multiple tabs 221 together at a position away from the active material coating portion 21 in the misaligned region Z2.

[0095] Among them, such as Figures 5-7 As shown, Figure 5 In the Z direction, the height of the tab 22 of the electrode assembly 2 is defined, and in the X direction, the width of the tab 22 of the electrode assembly 2 is defined. Figure 6 and Figure 7 The Y direction is the thickness direction of the tab portion 22 of the electrode assembly 2.

[0096] Generally speaking, before welding the tab 22 to the terminal post 12, the tab 22 needs to be cut first, and then the welding nozzle is pressed onto the welding position of the tab 22. Otherwise, if the welding nozzle is pressed onto the loose area of ​​the tab 22, welding defects will occur. Furthermore, the loose tab 22 is not easy to pass through the through hole structure, which affects the assembly efficiency of the battery cell 10 and is also easy to be scratched.

[0097] This application forms a second welded portion 2212 by welding the misaligned region Z2 of multiple tabs 221 away from the active material coating portion 21. Before welding the tab 22 to the terminal post 12, the second welded portion 2212 can be partially cut or not cut as needed. Since the second welded portion 2212 formed after welding the misaligned region Z2 has a certain rigidity relative to the multi-layered and fluffy tabs 221, the second welded portion 2212 can also support the welding nozzle, improve the stability of the welding nozzle, thereby improving the welding quality between the tab 22 and the terminal post 12, increasing the area of ​​the weldable area between the tab 22 and the terminal post 12, and ensuring the current flow area to ensure the fast charging performance of the battery cell 10.

[0098] In the technical solution of this application embodiment, by welding the overlapping area Z1 of multiple tabs 221 to form a first welding part 2211, and welding the misaligned area Z2 of multiple tabs 221 away from the active material coating part 21 to form a second welding part 2212, the area of ​​the welding region of multiple tabs 221 can be increased. On the one hand, the utilization rate of the tabs 22 is improved, which is conducive to increasing the capacity of the battery cell 10 and reducing the overcurrent temperature rise. On the other hand, when the tabs 22 are welded to the terminal post 12, the second welding part 2212 can better support the welding nozzle compared to the fluffy multiple tabs, and will not have problems such as wrinkles. It reduces the welding defects caused by the welding nozzle pressing into the fluffy area of ​​multiple tabs 221 in related technologies, reduces the cutting requirements of the welded tabs 22, saves costs, and improves the fast charging performance of the battery cell 10.

[0099] Furthermore, by welding the misaligned region Z2 to form a second welded part 2212, the efficiency of the tab 22 passing through the through hole structure can be improved, thereby improving the assembly efficiency of the battery cell 10 and making the tab 22 less susceptible to scratches from the hole wall of the through hole structure.

[0100] In some embodiments, the first welding portion 2211 and the second welding portion 2212 are connected, that is, the junction of the first welding portion 2211 and the second welding portion 2212 is fused together, so that the first welding portion 2211 and the second welding portion 2212 are connected together.

[0101] In the above technical solution, compared with the loose multiple tabs 221, the first welding part 2211 and the second welding part 2212 connected together can, on the one hand, improve the rigidity of the multiple tabs 221 after welding to a certain extent, making the tabs 22 less likely to be scratched by the hole wall of the through hole structure, and improving the efficiency of the tabs 22 passing through the through hole structure. On the other hand, the second welding part 2212 formed after welding is less likely to collapse under pressure compared with the first welding part 2211, which can effectively support the welding nozzle and will not cause wrinkles or other problems. It can reduce the welding defects caused by the welding nozzle pressing into the loose area of ​​the multiple tabs 221 in related technologies.

[0102] Please refer to this again. Figure 5 Along the width direction of the tab 22, the ratio of the width dimension of the first welding part 2211 to the width dimension of the second welding part 2212 is in the range of 0.8-1.2.

[0103] Specifically, the width direction of the tab portion 22 is perpendicular to the height direction of the tab portion 22, and the height direction of the tab portion 22 is parallel to the height direction of the active material coating portion 21. The width dimension of the first welding portion 2211 is L1, and the width dimension of the second welding portion 2212 is L2. L1 and L2 can be equal, or L1 > L2, or L1 < L2. For example, L1 / L2 can be 0.8, 0.9, 1, 1.1, 1.2, etc.

[0104] In the above technical solution, by limiting the ratio range of the width dimensions of the first welding part 2211 and the second welding part 2212, the area of ​​the welding region of the multiple tabs 221 can be increased, the utilization rate of the tab 22 can be improved, which is beneficial to increasing the capacity of the battery cell 10, reducing the overcurrent temperature rise, and also reducing the problem of welding defects caused by the welding nozzle being pressed into the fluffy area of ​​the multiple tabs 221 in related technologies.

[0105] In some embodiments, along the width direction of the tab 22, the ratio of the width dimension of the first welding portion 2211 to the width dimension of the tab 22 is in the range of 0.6-1. Specifically, the width dimension of the first welding portion 2211 is L1, and the width dimension of the tab 22 is L. For example, L1 / L can be 0.6, 0.7, 0.8, 0.9, 1, etc.

[0106] In the above technical solution, by limiting the ratio range of the width dimensions of the first welding part 2211 and the tab part 22, the area of ​​the welding region of the multiple tabs 221 can be increased, the utilization rate of the tab part 22 can be improved, which is beneficial to increasing the capacity of the battery cell 10, reducing the overcurrent temperature rise, and also reducing the problem of welding defects caused by the welding nozzle being pressed into the fluffy area of ​​the multiple tabs 221 in related technologies.

[0107] Please refer to this again. Figure 6 and Figure 7 Along the height direction of the tab 22, the height ratio of the second welding part 2212 to the first welding part 2211 is 0.08-0.2.

[0108] Specifically, the height direction of the tab portion 22 is parallel to the height direction of the active material coating portion 21, the height dimension of the first welding portion 2211 is h1, and the height dimension of the second welding portion 2212 is h2. For example, h2 / h1 can be 0.08, 0.1, 0.15, 0.2, etc.

[0109] Due to factors such as manufacturing method and manufacturing tolerance, it is difficult to strictly align the multi-layered tabs 221 after they are stacked, resulting in misalignment of the edges. The height of the misaligned (misaligned) parts is usually small. This application needs to strictly control the height dimensions of the misaligned area Z2 and the overlapping area Z1 after the multiple tabs 221 are stacked, so that the ratio of the height dimensions of the second welded part 2212 and the first welded part 2211 formed after welding meets the requirements.

[0110] In the above technical solution, by limiting the ratio range of the height dimensions of the first welding part 2211 and the second welding part 2212, the height dimension of the first welding part 2211 is made as large as possible and the height dimension of the second welding part 2212 is made as small as possible. This can improve the utilization rate of the tab 22 and reduce the cutting area of ​​the tab 22. When welding the tab 22 and the pole post 12, it can not only improve the stability of the welding press fitting onto the tab 22, but also increase the welding area between the tab 22 and the pole post 12, thereby increasing the welding reliability between the tab 22 and the pole post 12.

[0111] In some embodiments, along the height direction of the tab 22, the height ratio of the first welding portion 2211 to the tab 22 is 0.45-0.65. Specifically, the height dimension of the first welding portion 2211 is h1, and the height dimension of the tab 22 is h. For example, h1 / h can be 0.45, 0.5, 0.55, 0.6, 0.65, etc.

[0112] In the above technical solution, by limiting the ratio range of the height dimensions of the first welding part 2211 and the tab part 22, the area of ​​the first welding part 2211 is increased, which can improve the utilization rate of the tab part 22, reduce the cutting area of ​​the tab part 22, help reduce the overcurrent temperature rise, improve the charging and discharging efficiency of the battery cell 10, and thus increase the capacity of the battery cell 10.

[0113] Please refer to this again. Figures 5-7Along the height direction of the tab 22, the height dimension of the second welding part 2212 is 1mm-2mm. For example, the height dimension h2 of the second welding part 2212 can be 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm or 2mm, etc.

[0114] In the above technical solution, by limiting the height of the second welding part 2212 to meet the above conditions, on the one hand, the proportion of the misaligned area Z2 of the multiple tabs 221 can be reduced as much as possible, the cutting area of ​​the tab 22 can be reduced, the pass rate of the electrode assembly 2 can be improved, and the quality of the battery cell 10 can be improved. On the other hand, based on the misalignment of the multiple tabs 221, welding the misaligned area Z2 can increase the area of ​​the welding area of ​​the multiple tabs 221, and reduce the welding defects caused by the welding nozzle pressing into the fluffy area of ​​the multiple tabs 221 in the related technology.

[0115] Please refer to this again. Figure 7 Due to factors such as manufacturing method and manufacturing tolerance, after the multilayer tabs 221 are stacked, an overlapping area Z1 and a misaligned area Z2 are formed. After the overlapping area Z1 is welded, a first welded part 2211 is formed, and after the misaligned area Z2 is welded, a second welded part 2212 is formed. The thickness of the second welded part 2212 gradually decreases in the direction away from the first welded part 2211. Whether or not this part is cut can be selected as needed. When cutting is required, it is easier to cut because the thickness of the second welded part 2212 gradually decreases.

[0116] In some embodiments, the second welding portion 2212 has a first surface 2214 and a second surface 2215, the first surface 2214 and the second surface 2215 may be disposed opposite to each other in the thickness direction of the tab portion 22, and at least one of the first surface 2214 and the second surface 2215 is disposed obliquely relative to the height direction of the tab portion 22.

[0117] For example, one side surface of the first weld portion 2211 in the thickness direction can be flush with the first surface 2214 in the thickness direction of the second weld portion 2212, while the second surface 2215 in the thickness direction of the second weld portion 2212 can be inclined relative to one side surface in the thickness direction of the second weld portion 2212, so that the thickness of the second weld portion 2212 gradually decreases in the direction away from the first weld portion 2211.

[0118] For example, the first surface 2214 and the second surface 2215 in the thickness direction of the second weld portion 2212 can extend in a direction away from the first weld portion 2211 toward each other, so that the thickness of the second weld portion 2212 gradually decreases in the direction away from the first weld portion 2211.

[0119] In the above technical solution, the second welding part 2212 is formed in the above form, which makes it easier to decide whether to cut it as needed and improves the convenience of cutting.

[0120] Please refer to this again. Figure 7 The maximum distance s between the first surface 2214 and the second surface 2215 is 0.5mm-1mm, that is, the maximum thickness of the second welded part 2212 is 0.5mm-1mm. For example, the maximum distance s between the first surface 2214 and the second surface 2215 is 0.5mm, 0.6mm, 0.8mm, 1mm, etc.

[0121] In the above technical solution, by limiting the maximum distance between the first surface 2214 and the second surface 2215 to meet the above range, on the one hand, it is convenient to decide whether to cut according to the needs, thus improving the convenience of cutting; on the other hand, it can reduce the difficulty of welding, reduce welding defects, and improve welding quality.

[0122] In some embodiments, the first surface 2214 extends along the height direction of the tab 22, the second surface 2215 is inclined relative to the height direction of the tab 22, and the distance between the first surface 2214 and the second surface 2215 gradually decreases in the direction away from the first weld portion 2211.

[0123] In other words, the first surface 2214 of the second welded part 2212 formed after welding can be flush with the first welded part 2211. When welding the tab 22 and the pole post 12, a larger welding nozzle can be used so that part of the welding nozzle can be pressed on the first welded part 2211 and another part can be pressed on the second welded part 2212. That is, the first welded part 2211 and the second welded part 2212 can support the welding nozzle at the same time. This not only reduces the welding difficulty, but also reduces the welding defects caused by the welding nozzle pressing onto the loose area of ​​multiple tabs in related technologies. It also reduces the cutting requirements of the tab after welding, saves costs, and improves the fast charging performance of the battery cell 10.

[0124] Therefore, in the above technical solution, the second welding part 2212 is formed in the above form, which on the one hand facilitates the decision on whether to cut it according to the needs, improves the convenience of cutting, and on the other hand reduces the welding difficulty, reduces welding defects, and improves welding quality.

[0125] In some embodiments, the included angle β between the first surface 2214 and the second surface 2215 is 10°-45°. For example, the included angle β between the first surface 2214 and the second surface 2215 can be 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, etc. By limiting the included angle between the first surface 2214 and the second surface 2215 to the above range, it is convenient to weld the portion of the misaligned region Z2 away from the active material coating part 21 using an ultrasonic mount and an ultrasonic welding head, thereby improving welding convenience and welding quality.

[0126] Since the tabs are made of metal sheets and are relatively soft, the first surface 2214 and the second surface 2215 are not completely flat. This can be due to wrinkles caused during production or processing. Therefore, the above angles are approximate and do not affect the protection of other values ​​within the error range.

[0127] Please refer to Figures 8-11 , Figure 8 A schematic diagram of the electrode tab 22 of the electrode assembly 2 provided in some embodiments of this application before mating; Figure 9 A schematic diagram of the structure of the electrode assembly 2 with the first ultrasonic welding base 81 and the first ultrasonic welding head 82 after pairing, provided in some embodiments of this application; Figure 10 A schematic diagram of the structure of the overlapping area Z1 of the electrode assembly 2 with the first ultrasonic welding seat 81 and the first ultrasonic welding head 82 before welding, provided in some embodiments of this application. Figure 11 This is a schematic diagram of the structure of the electrode assembly 2 provided in some embodiments of this application, wherein the overlapping area Z1 of the tab portion 22 is formed by ultrasonic welding to form a first weld portion 2211. The first weld portion 2211 is formed by ultrasonic welding.

[0128] Specifically, after the multiple tabs 221 are paired, the multiple tabs 221 are stacked. The stacked multiple tabs 221 have an overlapping area Z1 and a misaligned area Z2. The overlapping area Z1 is sandwiched between the first ultrasonic welding seat 81 and the first ultrasonic welding head 82. Friction occurs between any two adjacent tabs 221 and they melt, thereby welding the multiple tabs 221 together in the overlapping area Z1 to form the first welded part 2211.

[0129] In the above technical solution, since the first welding part 2211 is formed by ultrasonic welding, the welding speed and welding efficiency can be improved, the surface quality of the overlapping area Z1 after welding can be improved, the welding process is clean, stable and reliable, and the energy consumption is low.

[0130] Please refer to Figures 12-14 , Figure 12A schematic diagram of the structure of the misaligned region Z2 of the electrode assembly 2 with the second ultrasonic welding seat 91 and the second ultrasonic welding head 92 before welding, provided in some embodiments of this application. Figure 13 This is a schematic diagram of the structure of the electrode assembly 2 provided in some embodiments of this application, wherein the misaligned region Z2 of the tab 22, which is away from the active material coating 21, is formed into a second welded part 2212 by ultrasonic welding. Figure 14 This is a schematic diagram of the structure of the electrode assembly 2 provided in some embodiments of this application. The second welding part 2212 is formed by ultrasonic welding.

[0131] Specifically, the misaligned region Z2, located away from the active material coating part 21, is sandwiched between the second ultrasonic welding base 91 and the second ultrasonic welding head 92. Friction occurs between any two adjacent tabs 221, causing them to melt. This welds multiple tabs 221 together at the misaligned region Z2, located away from the active material coating part 21, thereby forming the second welding part 2212.

[0132] In the above technical solution, since the second welding part 2212 is formed by ultrasonic welding, the welding speed and welding efficiency can be improved, the surface quality of the overlapping area Z1 after welding can be improved, the welding process is clean, stable and reliable, and the energy consumption is low.

[0133] In other embodiments, the misaligned region Z2 after the multiple tabs 221 are stacked includes an end misaligned region Z21. The end misaligned region Z21 is located at the end of the overlapping region Z1 away from the active material coating portion 21. The first part of the end misaligned region Z21 is bent along the direction close to the active material coating portion 21 toward the remaining second part of the end misaligned region Z21 and stacked together and welded together to form a second welded portion 2212.

[0134] Specifically, the misaligned area Z21 at the end of the multilayer tab 221 will adversely affect the subsequent assembly of the tab 22 and the laser welding of the tab 22 and the pole post 12. Therefore, in the related technology, during the production process of the electrode assembly 2, the misaligned area Z21 at the end of the multilayer tab 221 needs to be completely cut off with a cutter, so that the multilayer tab 221 only retains the overlapping area Z1 without misalignment. After cutting, the multilayer tab 221 in the remaining overlapping area Z1 is ultrasonically pre-welded to form the tab 22, and then the tab 22 and the pole post 12 are laser welded. However, in order to improve the cutting quality, the position of the cutter needs to be adjusted in real time during the cutting of tab 221. Moreover, when the relative positions of multiple tabs 22 on electrode assemblies 2 of different specifications are different, the position of the cutter also needs to be adjusted to cut multiple tabs 22 on electrode assemblies 2 of different specifications at the same time. Therefore, the processing efficiency is low. In addition, the length of the tab 22 after cutting is shortened, the weld area after welding with the electrode post 12 is smaller, the current carrying capacity is reduced, the charging and discharging efficiency of the battery cell 10 is affected, and there is a problem of material waste of tab 221.

[0135] In the embodiments of this application, the end misalignment region Z21 of the multilayer tab 221 is bent, stacked, and connected to achieve reuse of the end misalignment region Z21. This improves the adverse effects of the end misalignment region Z21 of the multilayer tab 221 on the subsequent assembly of the tab 22 (e.g., passing the tab 22 through the perforation on the terminal post 12) and on the subsequent welding of the tab 22 to the terminal post 12 or the adapter piece. Moreover, compared to cutting off the entire end misalignment region Z21, this is equivalent to increasing the ultrasonic pre-welding area of ​​the tab 22, thereby increasing the area of ​​electrical connection between the tab 22 and the terminal post 12, which is beneficial to improving the overcurrent capacity and the charging and discharging efficiency of the battery cell 10. Furthermore, since there is no need to use a cutter to cut the misaligned area Z21 at the end of the tab 22, the time spent adjusting the cutter in the cutting process is eliminated. Also, since multiple tabs 22 of the electrode assembly 2 do not need to be cut simultaneously, eliminating the need for a cutter adjustment step, this helps to speed up the production cycle of the electrode assembly 2 and improve its production efficiency. In addition, since the misaligned area Z21 at the end of the multilayer tab 221 is reused, material waste is reduced, and the material utilization rate of the tab 22 is improved.

[0136] Please refer to Figure 15 and Figure 16 , Figure 15 A partial enlarged view of the electrode assembly 2 provided in other embodiments of this application; Figure 16This is a top view of the electrode assembly 2 provided in some other embodiments of this application. In yet another embodiment, the misaligned region Z2 is welded to at least one side of the overlapping region Z1 to form a third weld portion 2213. Specifically, the misaligned region Z2 after the plurality of tabs 221 are stacked includes two side misaligned regions Z22, which are located on both sides of the overlapping region Z1 in the width direction, and at least one side misaligned region Z22 is welded to form the third weld portion 2213.

[0137] In the above technical solution, by welding the misaligned region Z2 to at least one side of the overlapping region Z1 to form the third welding part 2213, on the one hand, the area of ​​the welding area of ​​the multiple tabs 221 can be increased, the utilization rate of the tab 22 can be improved, which is conducive to increasing the capacity of the battery cell 10 and reducing the overcurrent temperature rise. On the other hand, it can reduce the welding defects caused by the welding nozzle being pressed into the fluffy area of ​​the multiple tabs 221 in the related technology, and it can also facilitate the tab 22 to pass through the perforation on the pole post 12.

[0138] Please refer to Figure 17 , Figure 17 This is a cross-sectional schematic diagram of the tab portion 22 of the electrode assembly 2 provided in some embodiments of this application. In still some embodiments, at least one first portion of the side misalignment region Z22 is bent and stacked together with the remaining second portion of the side misalignment region Z22 in a direction close to the active material coating portion 21, and welded together to form a third weld portion 2213.

[0139] Specifically, the side misalignment area Z22 of the stacked multilayer tabs 221 will adversely affect the subsequent assembly of the tabs 22 and the laser welding of the tabs 22 and the pole post 12. Therefore, in the related technology, during the production process of the electrode assembly 2, the side misalignment area Z22 of the multilayer tabs 221 needs to be completely cut off with a cutter, so that the multilayer tabs 221 only retain the overlapping area Z1 without misalignment. After cutting, the multilayer tabs 221 in the remaining overlapping area Z1 are ultrasonically pre-welded to form the tabs 22, and then the tabs 22 and the pole post 12 are laser welded. However, in order to improve the cutting quality, the position of the cutter needs to be adjusted in real time during the cutting of tab 221. Moreover, when the relative positions of multiple tabs 22 on electrode assemblies 2 of different specifications are different, the position of the cutter also needs to be adjusted to cut multiple tabs 22 on electrode assemblies 2 of different specifications at the same time. Therefore, the processing efficiency is low. In addition, the length of the tab 22 after cutting is shortened, the weld area after welding with the electrode post 12 is smaller, the current carrying capacity is reduced, the charging and discharging efficiency of the battery cell 10 is affected, and there is a problem of material waste of tab 221.

[0140] In the embodiments of this application, the side misalignment area Z22 of the multilayer tab 221 is bent, stacked, and connected to achieve reuse of the side misalignment area Z22. This improves the adverse effects of the side misalignment area Z22 of the multilayer tab 221 on the subsequent assembly of the tab 22 (e.g., passing the tab 22 through the perforation on the terminal post 12) and on the subsequent welding of the tab 22 to the terminal post 12 or the adapter piece. Moreover, compared to cutting off the entire side misalignment area Z22, it is equivalent to increasing the ultrasonic pre-welding area of ​​the tab 22, thereby increasing the area of ​​electrical connection between the tab 22 and the terminal post 12, which is beneficial to improving the overcurrent capacity and the charging and discharging efficiency of the battery cell 10. Furthermore, since there is no need to use a cutter to cut the side misalignment area Z22 of the tab 22, the time for adjusting the cutter in the cutting process is saved. Also, since multiple tabs 22 of the electrode assembly 2 do not need to be cut simultaneously, eliminating the need for a cutter adjustment step, this helps to speed up the production cycle of the electrode assembly 2 and improve its production efficiency. In addition, since the side misalignment area Z22 of the multilayer tab 221 is reused, material waste is reduced, and the material utilization rate of the tab 22 is improved.

[0141] In summary, by bending and stacking the layers together, the misaligned area Z2 of the multi-layer tab 221 is reused, which solves the adverse effects of the misaligned area Z2 of the multi-layer tab 221 on subsequent processes. At the same time, it increases the electrical connection area between the tab 22 and the pole 12, improves the current carrying capacity, eliminates the process and time of real-time adjustment of the cutter position, and helps to improve the processing efficiency of the electrode assembly 2, meet the cycle time requirements of high-speed mass production lines, and also helps to reduce material waste and improve the material utilization rate of the tab 221.

[0142] Please refer to this again. Figure 3 and Figure 4 According to some embodiments of this application, this application provides a battery cell 10. The battery cell 10 includes a housing 11 and an electrode assembly 2. The housing 11 is provided with a terminal post 12, the electrode assembly 2 is disposed inside the housing 11, and the electrode tab 22 is connected to the terminal post 12. The electrode assembly 2 is the electrode assembly 2 of any of the above embodiments.

[0143] In the technical solution of this application embodiment, by adopting the above-mentioned electrode assembly 2, on the one hand, the utilization rate of the tab 22 is improved, which is conducive to increasing the capacity of the battery cell 10 and reducing the overcurrent temperature rise. On the other hand, when welding the tab 22 to the terminal post 12, the second welding part 2212 can better support the welding nozzle compared to the multiple loose tabs, and there will be no wrinkles or other problems. This reduces the welding defects caused by the welding nozzle pressing into the loose area of ​​the multiple tabs 221 in related technologies, thereby improving the reliability of the battery cell 10, reducing the cutting requirements of the welded tab 22, thereby reducing the production difficulty of the battery cell 10, saving costs, and improving the fast charging performance of the battery cell 10.

[0144] Please refer to Figure 12 and Figure 13 , Figure 12 This is a partial cross-sectional schematic diagram of a battery cell 10 provided in some embodiments of this application. Figure 13 This is a partial cross-sectional schematic diagram of a battery cell 10 provided in some embodiments of this application. The terminal post 12 has a receiving portion 121, at least a portion of the tab 22 extends into and is received within the receiving portion 121, and the tab 22 is electrically connected to the terminal post 12. That is, the terminal post 12 is configured as a hollow structure.

[0145] This means, at least partially, that the tab 22 can be entirely housed within the receiving portion 121, or that only a portion of the tab 22 can be housed within the receiving portion 121. Because the terminal post 12 is provided with the receiving portion 121, the hollow structure of the receiving portion 121 can, on the one hand, reduce the weight of the terminal post 12 to a certain extent, thereby increasing the weight energy density of the battery cell 10 and the battery 100. On the other hand, the tab 22 can be housed within the receiving portion 121, improving the assembly efficiency of the tab 22 and saving space occupied by the tab 22. This fully utilizes the space of the battery cell 10, making the fit between the support 3 and the terminal post 12, and between the support 3 and the tab 22, tighter and more reliable. This results in a more compact structure for the battery cell 10, which is more conducive to increasing the energy density of the battery cell 10.

[0146] More specifically, by partially or entirely accommodating the tab 22 within the receiving portion 121, the portion of the tab 22 located within the receiving portion 121 can occupy space within the terminal post 12. This reduces the space occupied by the tab 22 within the housing 11. When the dimensions of the housing 11 are fixed, some space can be saved within the housing 11 to accommodate a larger active material coating portion 21, thereby increasing the volumetric energy density of the battery cell 10. For example, when the tab 22 is led out from the side of the active material coating portion 21 closest to the terminal post 12, the space occupied by the tab 22 between the active material coating portion 21 and the terminal post 12 can be saved. This increases the size of the active material coating portion 21 in the direction in which the tab 22 is led out, reduces the distance between the active material coating portion 21 and the terminal post 12, and increases the energy density of the battery cell 10.

[0147] Meanwhile, by accommodating at least a portion of the tab 22 within the receiving portion 121, the space occupied by the battery cell 10 itself can be reduced, allowing a larger number of battery cells 10 to be accommodated in the same volume of battery 100, and also increasing the volumetric energy density of battery 100. In addition, by accommodating at least a portion of the tab 22 within the receiving portion 121 to occupy the space within the terminal post 12, the redundancy of the tab 22 within the casing 11 can be reduced to at least a certain extent, reducing the probability of short circuit between the tab 22 and the active material coating portion 21, reducing the probability of short circuit in battery cell 10, and improving the operational reliability and stability of battery cell 10 and battery 100.

[0148] It should be noted that, in the embodiments of this application, the position of the receiving portion 121 can be located either on the side of the pole 12 facing the active material coating portion 21 or on the side of the pole 12 away from the active material coating portion 21.

[0149] For example, please refer to again Figure 12 and Figure 13 When the receiving portion 121 is located on the side of the pole 12 facing the active material coating portion 21, the receiving portion 121 includes a first receiving groove 12110, the surface of the pole 12 facing the active material coating portion 21 is the inner end face 122 of the pole, the groove opening of the first receiving groove 12110 is formed on the inner end face 122 of the pole, and at least a portion of the tab portion 22 is received in the first receiving groove 12110.

[0150] For example, the first receiving groove 12110 is a groove body, which is a groove-shaped structure with a certain depth. For instance, when the pole post 12 is disposed on the upper end wall of the housing 11, and the inner end face 122 of the pole post is the lower surface of the pole post 12, the first receiving groove 12110 is formed as a receiving groove with the opening facing downward and the groove wall recessed upward. As another example, when the pole post 12 is disposed on the lower end wall of the housing 11, and the inner end face 122 of the pole post is the upper surface of the pole post 12, the first receiving groove 12110 is formed as a receiving groove with the opening facing upward and the groove wall recessed downward.

[0151] In the above technical solution, on the one hand, opening a first receiving groove 12110 on the electrode post 12 can reduce the weight of the electrode post 12 to a certain extent, thereby increasing the weight energy density of the battery cell 10 and the battery 100; on the other hand, since the opening of the first receiving groove 12110 is formed on the inner end face 122 of the electrode post, and the inner end face 122 of the electrode post 12 is the surface of the electrode post 12 near the active material coating portion 21, the first receiving groove 12110 can open towards the active material coating portion 21, thereby facilitating the insertion of the tab portion 22 into the first receiving groove 12110 and improving assembly efficiency. Moreover, this type of first receiving groove 12110 is easy to process and improves production efficiency.

[0152] Furthermore, the first receiving groove 12110 is easy to process into a larger volume, which can accommodate more tabs 22; at the same time, since the first receiving groove 12110 is open towards the active material coating part 21, the first receiving groove 12110 can also serve as a buffer and temporary storage structure for electrolyte, allowing the casing 11 to hold more electrolyte. Since the battery cell 10 loses electrolyte during charging and discharging, more electrolyte can extend the service life of the battery cell 10; and also because the first receiving groove 12110 is open towards the active material coating part 21, the first receiving groove 12110 can also serve as a receiving and buffering structure for gas generated inside the electrode assembly 2, reducing the expansion of the battery cell 10 and improving the reliability and stability of the battery cell 10.

[0153] In addition, since the first receiving groove 12110 is located inside the electrode post 12, external foreign objects and impurities are not easy to enter the first receiving groove 12110, which can reduce the impact of external foreign objects and impurities on the electrode assembly 2, improve the stability and reliability of the electrode assembly 2, and thus improve the stability and reliability of the battery cell 10 and the battery 100.

[0154] Please refer to this again. Figure 12In the embodiments of this application, the connection method between the electrode post 12 and the housing 11 is not limited; for example, it can be welding or riveting. For example, when the two are joined by riveting, the housing 11 has a mounting hole 113, and the electrode post 12 is riveted and installed in the mounting hole 113. Of course, it is understood that when the two are joined by welding or other methods, the housing 11 may also have a mounting hole 113 to facilitate the installation of the electrode post 12 into the housing 11 through the mounting hole 113; this is not limited here.

[0155] Meanwhile, the first receiving groove 12110 can be positioned corresponding to the mounting hole 113. In other words, on the projection plane perpendicular to the axial direction R of the pole post 12, the orthographic projection of the first receiving groove 12110 is within the orthographic projection range of the mounting hole 113, allowing the first receiving groove 12110 to have a greater depth to accommodate more pole tabs 22, thereby reducing the space occupied by the pole tabs 22 within the housing 11 to a greater extent. Specifically, when the housing 11 has a mounting hole 113 and the pole post 12 is installed in the mounting hole 113, the depth H1 of the first receiving groove 12110 along the axial direction R of the pole post 12 is greater than or equal to the minimum distance H2 from the inner end face 122 of the pole post to the mounting hole 113.

[0156] It should be noted that the specific shape of the first receiving groove 12110 is not limited. It can be a regular shape or an irregular shape, such as a cylindrical groove with a rectangular, elliptical, or racetrack-shaped cross-section, a trapezoidal groove with a rectangular cross-section and gradually changing cross-sectional dimensions, a hemispherical groove with a circular cross-section and gradually changing cross-sectional dimensions, or a semi-ellipsoidal groove with an elliptical cross-section and gradually changing cross-sectional dimensions, etc. Therefore, the depth H1 of the first receiving groove 12110 refers to the maximum depth of the first receiving groove 12110 along the axial direction R of the pole post 12.

[0157] Since the depth H1 of the first receiving groove 12110 along the axial direction R of the electrode post 12 is greater than or equal to the minimum distance H2 from the inner end face 122 of the electrode post to the mounting hole 113, the volume of the electrode post 12 can be fully utilized, resulting in a larger depth of the first receiving groove 12110. This is beneficial for accommodating more tabs 22, thereby reducing the space occupied by the tabs 22 in the housing 11 to a greater extent, further improving the energy density of the battery cell 10, and further reducing the redundancy of the tabs 22 in the housing 11. At the same time, since the first receiving groove 12110 has a larger depth, it can also accommodate the gas generated by the electrode assembly 2, improving the reliability and stability of the battery cell 10, and can also accommodate more electrolyte, thereby improving the service life of the battery cell 10.

[0158] Please refer to this again. Figure 12 and Figure 13In order to improve the stability and reliability of the electrical connection between the active material coating part 21 and the electrode post 12, in some embodiments of this application, the electrical connection position between the electrode tab 22 and the electrode post 12 can be located on the groove wall of the first receiving groove 12110 formed by the receiving part 121.

[0159] Exemplarily, the tab 22 and the post 12 can be electrically connected by welding, with the welding position being the connection point between the tab 22 and the post 12. Furthermore, the welding method between the tab 22 and the post 12 is not limited; for example, it can be laser welding. Depending on the position, angle, or structure of the welding area, vertical welding, inclined welding, lap welding, or edge sealing welding can be selected. In other embodiments of this application, the tab 22 and the post 12 can also be electrically connected using other methods instead of welding, such as using conductive adhesive or conductive pins. For simplicity, the following description uses the example of the tab 22 and the post 12 being electrically connected by welding, with the welding position being the connection point between the tab 22 and the post 12.

[0160] Specifically, the electrode post 12 includes a first end wall 12111 and a first side wall 12113. The first end wall 12111 is located on the side of the first side wall 12113 away from the active material coating portion 21. The first end wall 12111 and the first side wall 12113 form a first receiving groove 12110. The electrical connection position between the electrode tab 22 and the electrode post 12 is located at the first end wall 12111 and / or the first side wall 12113. That is, the electrode tab 22 can be welded to at least one of the first end wall 12111 and the first side wall 12113.

[0161] In the above technical solution, by setting the electrical connection position between the tab 22 and the terminal post 12 on at least one of the first end wall 12111 and the first side wall 12113, the first receiving groove 12110 not only serves to accommodate at least a portion of the tab 22, but its groove wall also serves to achieve electrical connection with the tab 22. This simplifies the structure of the terminal post 12, facilitates its processing, and reduces redundancy and cost. Furthermore, by utilizing the groove wall of the first receiving groove 12110 to achieve electrical connection with the tab 22, the area where the tab 22 is electrically connected to the terminal post 12 can be relatively large. This not only reduces the difficulty of electrical connection but also improves the reliability and stability of the electrical connection, thereby enhancing the performance of the battery cell 10.

[0162] Furthermore, since the electrical connection between the tab 22 and the pole post 12 is located within the first receiving groove 12110, not only can the electrical connection protrude from the outside of the pole post 12 and occupy space outside the pole post 12, but the electrical connection can also be protected by the pole post 12, thereby improving the reliability and stability of the electrical connection between the tab 22 and the pole post 12.

[0163] In addition, in the embodiments of this application, the first end wall 12111 is constructed as a closed structure without perforations 12130, so that the first receiving groove 12110 is isolated from the external space of the housing 11, which can reduce the problem of electrolyte leakage from the first receiving groove 12110 inside the housing 11.

[0164] Please refer to this again. Figure 12 and Figure 13 In some alternative embodiments, the partial shape of the tab 22 matches the partial shape of the first end wall 12111, and is fitted together to achieve electrical connection, such that the position where the tab 22 is electrically connected to the first end wall 12111 extends along the length or width direction of the first end wall 12111. For example, when the first end wall 12111 is planar, a portion of the tab 22 can also be planar and fitted to the first end wall 12111, and an electrical connection, such as welding, can be performed at the fitted position. This increases the area of ​​the electrical connection, improving its reliability and stability.

[0165] In addition, when the electrical connection between the tab 22 and the first end wall 12111 is welding, since the first end wall 12111 is located on the side of the first receiving groove 12110 away from the active material coating part 21, it is convenient to perform welding operations. For example, welding can be performed from the side of the pole 12 away from the active material coating part 21.

[0166] It is worth noting that the shape of the first end wall 12111 is not limited, for example, it can be a flat plate, an arc-shaped plate, etc. Among them, when the first end wall 12111 is a flat plate structure, the first end wall 12111 is arranged at an angle to the axial direction R of the pole post 12. For example, it can be a flat plate structure perpendicular to the axial direction R of the pole post 12, or it can be an inclined plate structure that is not perpendicular to the axial direction R of the pole post 12, but the inclination direction is not limited.

[0167] Of course, in other embodiments of this application, the position where the tab 22 is electrically connected to the first end wall 12111 may not extend along the length or width of the first end wall 12111. For example, it may be a plurality of discretely arranged points. For example, the tab 22 has a plurality of spaced-apart portions that are welded to the first end wall 12111 respectively, which will not be elaborated here.

[0168] Please refer to Figure 14 , Figure 14This is a partial cross-sectional schematic diagram of a battery cell 10 provided in some embodiments of this application. When the tab 22 is electrically connected to the first end wall 12111, a first groove 12112 can be provided on the first end wall 12111, and the downward direction of the first groove 12112 is away from the direction of the active material coating portion 21. At least a portion of the position where the tab 22 is electrically connected to the first end wall 12111 is located within the first groove 12112. Exemplarily, at least a portion of the tab 22 can be disposed within the first groove 12112 and connected to the portion of the first end wall 12111 used to define the first groove 12112.

[0169] In the above technical solution, on the one hand, the first groove 12112 can be used to pre-position and limit the electrical connection position of the tab 22, which is not only conducive to finding the correct position to realize the electrical connection and improving production efficiency, but also conducive to improving the stability and reliability of the tab 22 and the stability and reliability of the charging and discharging process of the battery cell 10. On the other hand, by setting the first groove 12112 on the first end wall 12111, the local wall thickness of the first end wall 12111 can be locally reduced, which is not only conducive to welding, but also conducive to reducing the weight of the pole 12 and increasing the weight energy density of the battery cell 10.

[0170] Please refer to this again. Figure 13 and Figure 14 In this embodiment of the application, the electrode post 12 may also be provided with a first groove 126 as required. The first groove 126 is located on the side of the electrode post 12 away from the active material coating part 21. That is, the surface of the electrode post 12 away from the active material coating part 21 is the outer end face 123 of the electrode post, and the groove of the first groove 126 is formed on the outer end face 123 of the electrode post.

[0171] It is understood that the first groove 126 is a groove body, which is a groove-shaped structure with a certain depth. Furthermore, when the electrode post 12 is disposed on the upper end wall of the housing 11, and the outer end face 123 of the electrode post is the upper surface of the electrode post 12, the first groove 126 is formed with the groove opening facing upwards and the groove wall recessed downwards (i.e., recessed towards the square shape of the electrode assembly 2). For example, when the electrode post 12 is disposed on the lower end wall of the housing 11, and the outer end face 123 of the electrode post is the lower surface of the electrode post 12, the first groove 126 is formed with the groove opening facing downwards and the groove wall recessed upwards (i.e., recessed away from the square shape of the electrode assembly 2).

[0172] In the above technical solution, on the one hand, since the pole post 12 is provided with the first groove 126, the weight of the pole post 12 can be further reduced, so as to improve the weight energy density of the battery cell 10 and the battery 100; on the other hand, the first groove 126 is located on the outside of the pole post 12, that is, it is open on the side of the pole post 12 facing away from the inside of the housing 11. The first groove 126 can be used to accommodate or install the structural components that electrically connect each battery cell 10 in the battery 100, so as to make full use of the space inside the pole post 12 and improve the space utilization rate and volume energy density of the battery 100.

[0173] Furthermore, since the electrode post 12 simultaneously has a first receiving groove 12110 and a first recess 126, and the first recess 126 is located on the side of the first receiving groove 12110 away from the active material coating portion 21, and the first recess 126 opens in the direction away from the first receiving groove 12110, it is convenient to perform laser welding of the tab portion 22 to the first end wall 12111 from the outside of the electrode post 12, that is, the side of the electrode post 12 away from the active material coating portion 21, through the first recess 126. In other words, it is convenient to achieve electrical connection between the tab portion 22 and the electrode post 12 through external welding. That is to say, with the above structural arrangement, it is convenient to perform external welding of the electrode post 12 and the tab portion 22 through the first recess 126, which facilitates the processing and manufacturing of the battery cell 10 and can save processing and manufacturing costs.

[0174] Furthermore, in order to facilitate and effectively weld the tab 22 to the wall of the first receiving groove 12110 via the first groove 126, and to improve the welding reliability of the tab 22 to the wall of the first receiving groove 12110, in the embodiments of this application, the portion between the first groove 126 and the first receiving groove 12110 can be laser welded to the tab 22, that is... Figure 14 The spacer portion 127 shown is laser-welded to the tab portion 22 to achieve electrical connection between the electrode assembly 2 and the electrode post 12. The spacer portion 127 of the electrode post 12, located between the first groove 126 and the first receiving groove 12110, is relatively thin. The spacer portion 127 isolates the first groove 126 and the first receiving groove 12110. The side wall of the spacer portion 127 near the active material coating portion 21 can serve as the first end wall 12111. When the tab portion 22 needs to be welded to the first end wall 12111, the relatively thin thickness of the spacer portion 127 facilitates the welding of the tab portion 22 and the first end wall 12111 through the first groove 126, improving the convenience and reliability of welding.

[0175] Please refer to this again. Figure 13Furthermore, the battery cell 10 may also include a slot cover 7, which is disposed on the terminal post 12 and covers the opening of the first groove 126. In the above technical solution, by providing the slot cover 7 that covers the first groove 126, the terminal post 12 can be indirectly electrically connected to the busbar component through the slot cover 7. By setting the position and structure of the slot cover 7, the electrical connection between the slot cover 7 and the busbar component is more convenient and the electrical connection area is larger. Thus, by providing the slot cover 7, the electrical connection between adjacent battery cells 10 within the battery 100 can be facilitated. Moreover, since the electrical connection between battery cells 10 is located at the slot cover 7, the electrical connection with the tab 22 and the terminal post 12 can be separated by the first groove 126, resulting in less interference between them and further improving the stability and reliability of the battery cell 10.

[0176] For example, please refer to Figure 15 , Figure 15 This is a partial cross-sectional view of a battery cell 10 provided in some embodiments of this application. The receiving portion 121 may also be configured to include a second receiving groove 12120. The surface of the electrode post 12 away from the active material coating portion 21 is the outer end face 123 of the electrode post. The groove opening of the second receiving groove 12120 is formed on the outer end face 123 of the electrode post. The second receiving groove 12120 communicates with the interior of the housing 11 through a through hole 12130. The tab portion 22 passes through the through hole 12130 and is at least partially received in the second receiving groove 12120.

[0177] It is understood that the second receiving groove 12120 is a groove body, which is a groove-shaped structure with a certain depth. For example, when the pole post 12 is set on the upper end wall of the housing 11, and the outer end face 123 of the pole post is the upper surface of the pole post 12, the second receiving groove 12120 is formed as a receiving groove with the groove opening facing upward and the groove wall concave downward. As another example, when the pole post 12 is set on the lower end wall of the housing 11, and the outer end face 123 of the pole post is the lower surface of the pole post 12, the second receiving groove 12120 is formed as a receiving groove with the groove opening facing downward and the groove wall concave upward.

[0178] In the above technical solutions, please refer again Figure 15On the one hand, the second receiving groove 12120 provided on the terminal post 12 can reduce the weight of the terminal post 12 to a certain extent, thereby improving the weight energy density of the battery cell 10 and the battery 100. On the other hand, since the opening of the second receiving groove 12120 is formed on the outer end face 123 of the terminal post, and the outer end face 123 of the terminal post is the surface of the terminal post 12 away from the active material coating part 21, the second receiving groove 12120 can be opened in the direction away from the active material coating part 21. In this way, when at least a part of the tab part 22 is accommodated in the second receiving groove 12120, the tab part 22 can be easily stored and organized through the opening of the second receiving groove 12120, and the electrical connection operation between the tab part 22 and the terminal post 12 can be easily performed through the opening of the second receiving groove 12120, thereby reducing the production difficulty of the battery cell 10 and improving the production efficiency of the battery cell 10.

[0179] Meanwhile, since the second receiving tank 12120 can communicate with the interior of the housing 11 through the perforation 12130, the second receiving tank 12120 can also serve as a buffer and temporary storage structure for the electrolyte, allowing the housing 11 to hold more electrolyte. Since the battery cell 10 loses electrolyte during charging and discharging, more electrolyte can extend the service life of the battery cell 10. Also, because the second receiving tank 12120 can communicate with the interior of the housing 11 through the perforation 12130, the second receiving tank 12120 can also serve as a receiving and buffering structure for gas generated inside the electrode assembly 2, reducing the expansion of the battery cell 10 and improving the reliability and stability of the battery cell 10.

[0180] It is worth noting that when the receiving portion 121 has a second receiving groove 12120, and the electrode tab 22 passes through the through hole 12130 and is at least partially received within the second receiving groove 12120, the electrical connection position between the electrode tab 22 and the electrode post 12 is not limited. For example, when the electrode tab 22 passes through the through hole 12130 and is at least partially received within the second receiving groove 12120, in the embodiments of this application, the electrical connection position between the electrode tab 22 and the electrode post 12 is located on the wall of the through hole 12130 formed by the electrode post 12.

[0181] In the above technical solution, by setting the electrical connection position between the tab 22 and the post 12 on the wall of the perforation 12130, it is convenient to perform electrical connection operation between the tab 22 and the post 12 through the second receiving groove 12120. Moreover, when the electrical connection area between the tab 22 and the post 12 is large, the perforation 12130 can be sealed by the electrical connection between the tab 22 and the post 12, so as to save sealing costs, reduce electrolyte leakage, and save sealing parts.

[0182] Specifically, the tab 22 can be welded to the hole wall of the perforation 12130 at the position where the perforation 12130 connects to the second receiving groove 12120. This facilitates operation, and the perforation 12130 can be sealed by controlling the solder stamp and the tab 22, thereby improving the problem of electrolyte leakage from the perforation 12130 inside the housing 11.

[0183] As another example, when the tab 22 passes through the through hole 12130 and is at least partially accommodated within the second receiving groove 12120, in some other embodiments of this application, the electrical connection point between the tab 22 and the pole post 12 can also be located on the groove wall of the second receiving groove 12120 formed by the pole post 12. This facilitates electrical connection operations; for example, when the tab 22 and the groove wall of the second receiving groove 12120 formed by the pole post 12 are welded, it can reduce the occurrence of conductive particles generated during welding entering the housing 11 and causing short circuits or other problems.

[0184] Please refer to this again. Figure 15 The electrode post 12 includes a second end wall 12121 and a second side wall 12123. The second end wall 12121 is located on the side of the second side wall 12123 near the active material coating portion 21. The second end wall 12121 and the second side wall 12123 form a second receiving groove 12120. A through hole 12130 is opened in the second end wall 12121. The electrical connection position between the electrode tab 22 and the electrode post 12 is located in the second end wall 12121 and / or in the second side wall 12123.

[0185] More specifically, the tab 22 and the post 12 can be electrically connected by welding, so the welding position is the electrical connection position between the tab 22 and the post 12. In other embodiments of this application, the tab 22 and the post 12 can also be electrically connected by other means instead of welding, such as by using conductive adhesive or conductive pins, which will not be elaborated here.

[0186] For simplicity, the following description will use the example of welding the tab 22 to the pole post 12 to form an electrical connection, with the welding position being the electrical connection position between the tab 22 and the pole post 12. For example, in some embodiments, the electrical connection position between the tab 22 and the pole post 12 is located at the second end wall 12121 and / or the second side wall 12123, which can be welding the tab 22 to at least one of the second end wall 12121 and the second side wall 12123.

[0187] In the above technical solution, by setting the electrical connection position between the tab 22 and the pole post 12 on at least one of the second end wall 12121 and the second side wall 12123, the second receiving groove 12120 not only serves to accommodate at least a portion of the tab 22, but the groove wall of the second receiving groove 12120 also serves to achieve electrical connection with the tab 22. This simplifies the structure of the pole post 12 and facilitates its processing. Furthermore, since the through hole 12130 is formed in the second end wall 12121, it facilitates the tab 22 to extend into the second receiving groove 12120 through the through hole 12130. This simplifies the structure of the tab 22, reduces redundancy in the tab 22, and lowers the cost of the tab 22. Furthermore, the open direction of the second receiving groove 12120 allows for easy electrical connection between the tab 22 and the groove wall of the second receiving groove 12120 through the groove opening, reducing the difficulty of electrical connection. Moreover, by utilizing the groove wall of the second receiving groove 12120 to achieve electrical connection with the tab 22, the area of ​​electrical connection between the tab 22 and the terminal post 12 can be relatively large, which can improve the reliability and stability of electrical connection, thereby improving the performance of the battery cell 10.

[0188] Furthermore, since the electrical connection between the tab 22 and the pole post 12 is located within the second receiving groove 12120, not only can the electrical connection protrude from the outside of the pole post 12 and occupy space outside the pole post 12, but the electrical connection can also be protected by the pole post 12, thereby improving the reliability and stability of the electrical connection between the tab 22 and the pole post 12.

[0189] Please refer to this again. Figure 15 In some embodiments, the partial shape of the tab 22 matches the partial shape of the second end wall 12121, and they are fitted together to achieve an electrical connection, such that the position where the tab 22 is electrically connected to the second end wall 12121 extends along the length or width direction of the second end wall 12121. For example, when the second end wall 12121 is planar, a portion of the tab 22 can also be planar and fitted to the second end wall 12121, and an electrical connection, such as welding, can be performed at the fitted position. This increases the area of ​​the electrical connection and improves the reliability and stability of the electrical connection.

[0190] It is worth noting that the shape of the second end wall 12121 is not limited, for example, it can be a flat plate or an arc-shaped plate structure. When the second end wall 12121 is a flat plate structure, the second end wall 12121 is arranged at an angle to the axial direction R of the pole post 12. For example, it can be a flat plate structure perpendicular to the axial direction R of the pole post 12, or it can be an inclined flat plate structure that is not perpendicular to the axial direction R of the pole post 12, but the direction of inclination is not limited.

[0191] For example, please refer to again Figure 15When the second end wall 12121 has a flat plate structure, the angle θ between the second end wall 12121 and the axial direction R of the pole post 12 is equal to 90°, that is, along the direction from the perforation 12130 to the second side wall 12123, the second end wall 12121 and the active material coating part 21 are equally spaced. This facilitates the welding of the tab part 22 to the second end wall 12121.

[0192] For example, the angle θ between the second end wall 12121 and the axial direction R of the pole post 12 is greater than 90°, that is, along the direction from the perforation 12130 to the second side wall 12123, the second end wall 12121 extends obliquely towards the active material coating portion 21. Therefore, the extension distance of the tab portion 22 along the second end wall 12121 can be increased, thereby increasing the reliability of the electrical connection. For example, the angle θ between the second end wall 12121 and the axial direction R of the pole post 12 can be 90°-145°, such as 100°, 110°, 120°, 130°, 140°, etc., which on the one hand makes the second end wall 12121 easier to process and facilitates electrical connection with the tab portion 22, and on the other hand allows for more efficient use of the space within the pole post 12 to accommodate the tab portion 22.

[0193] For example, the angle θ between the second end wall 12121 and the axial direction R of the pole post 12 is less than 90°, that is, along the direction from the perforation 12130 to the second side wall 12123, the second end wall 12121 extends obliquely in a direction away from the active material coating part 21.

[0194] Therefore, the extension distance of the tab 22 along the second end wall 12121 can be increased to enhance the reliability of the electrical connection. For example, the angle θ between the second end wall 12121 and the axial direction R of the pole post 12 can be 45°-90°, such as 50°, 60°, 70°, 80°, etc. This makes the second end wall 12121 easier to process and facilitates electrical connection with the tab 22, and also makes fuller use of the space within the pole post 12 to accommodate the tab 22.

[0195] Of course, this application is not limited to this. In other embodiments of this application, the position where the electrode tab 22 is electrically connected to the second end wall 12121 may not extend along the length or width direction of the second end wall 12121. Instead, it may be a plurality of discretely arranged points. For example, the electrode tab 22 has a plurality of spaced-apart portions that are welded to the second end wall 12121 respectively. This will not be elaborated here.

[0196] Please refer to this again. Figure 15 and further refer to Figure 16 , Figure 16This is a partial cross-sectional schematic diagram of a battery cell 10 provided in some embodiments of this application. Regardless of the specific value of the angle θ between the second end wall 12121 and the axial direction R of the electrode post 12, in the embodiments of this application, when the tab 22 is electrically connected to the second end wall 12121, a second recess 12122 can be provided on the second end wall 12121 as needed. The second recess 12122 is a groove formed by a portion of the second end wall 12121 sinking down towards the end near the active material coating portion 21. The position where the tab 22 is electrically connected to the second end wall 12121 is at least partially located within the second recess 12122.

[0197] In the above technical solution, the portion of the tab 22 located within the second sink 12122 is configured to match the shape of the second sink 12122 and fit together to achieve electrical connection. The second sink 12122 can be used to pre-position and limit the electrical connection position of the tab 22, which is beneficial to accurately locate the position for electrical connection, improve production efficiency, and improve the stability and reliability of the electrical connection position, thereby improving the reliability and stability of the charging and discharging operation of the battery cell 10.

[0198] Please refer to this again. Figure 16 In the embodiments of this application, the connection method between the pole piece 12 and the housing 11 is not limited. For example, it can be welding or riveting. For instance, when the two are joined by riveting, the housing 11 has a mounting hole 113, and the pole piece 12 is riveted and installed in the mounting hole 113. Of course, it is understood that when the two are joined by welding or other methods, the housing 11 may also have a mounting hole 113, and the pole piece 12 is installed in the mounting hole 113.

[0199] Optionally, please refer to again Figure 15 The second receiving groove 12120 can be set at the position corresponding to the mounting hole 113. In other words, on the projection plane perpendicular to the axial direction R of the pole post 12, the orthographic projection of the second receiving groove 12120 is located within the orthographic projection range of the mounting hole 113, so that the second receiving groove 12120 can have a larger depth to accommodate more pole tabs 22, thereby reducing the space occupied by the pole tabs 22 in the housing 11 to a greater extent.

[0200] In some embodiments, please refer again Figure 15 When the housing 11 has a mounting hole 113 and the pole post 12 is installed in the mounting hole 113, along the axial direction R of the pole post 12, the depth H3 of the second receiving groove 12120 is greater than or equal to the minimum distance H4 from the outer end face 123 of the pole post to the mounting hole 113.

[0201] It should be noted that the specific shape of the second receiving groove 12120 is not limited. It can be a regular shape or an irregular shape, such as a cylindrical groove with a rectangular, elliptical, or racetrack-shaped cross-section, a trapezoidal groove with a rectangular cross-section and gradually changing cross-sectional dimensions, a hemispherical groove with a circular cross-section and gradually changing cross-sectional dimensions, or a semi-ellipsoidal groove with an elliptical cross-section and gradually changing cross-sectional dimensions, etc. It is worth noting that the racetrack shape mentioned in this article refers to a shape in which the two short sides of a rectangle are replaced by outwardly convex curves.

[0202] Therefore, the depth H3 of the second receiving groove 12120 refers to the maximum depth of the second receiving groove 12120 along the axial direction R of the electrode post 12. Since the depth H3 of the second receiving groove 12120 along the axial direction R of the electrode post 12 is greater than or equal to the minimum distance H4 from the outer end face 123 of the electrode post to the mounting hole 113, the volume of the electrode post 12 can be fully utilized, resulting in a larger depth of the second receiving groove 12120. This is beneficial for accommodating more tabs 22, thereby reducing the space occupied by the tabs 22 in the housing 11 to a greater extent, further improving the energy density of the battery cell 10, and further reducing the redundancy of the tabs 22 in the housing 11. At the same time, since the second receiving groove 12120 has a larger depth, it can also accommodate the gas generated by the electrode assembly 2, improving the reliability and stability of the battery cell 10, and can also accommodate more electrolyte, thereby improving the service life of the battery cell 10.

[0203] Please refer to Figure 16 and further refer to Figure 17 , Figure 17 This is a partial cross-sectional schematic diagram of a battery cell 10 provided in some embodiments of this application. In the embodiments of this application, when the receiving portion 121 has the second receiving groove 12120 of any of the above embodiments, optionally, the battery cell 10 may further include a cover plate 13, which cooperates with the terminal post 12 and closes the opening of the second receiving groove 12120, and the cover plate 13 is electrically connected to the terminal post 12.

[0204] In the above technical solution, by setting a cover plate 13 to close the opening of the second receiving tank 12120, the leakage of electrolyte in the housing 11 from the opening of the second receiving tank 12120 can be reduced. Moreover, since the cover plate 13 closes the opening of the second receiving tank 12120 and is electrically connected to the electrode post 12, the indirect electrical connection between the electrode post 12 and the busbar component can be easily achieved by using the cover plate 13. Furthermore, it is beneficial to increase the connection area at the electrical connection point, thereby helping to reduce the resistance at the electrical connection point.

[0205] It is worth noting that the matching method and position of the cover plate 13 and the pole post 12 are not limited, as long as the cover plate 13 can close the opening of the second receiving groove 12120. For example, in some embodiments, the cover plate 13 can be welded to the pole post 12. During processing, the pole lug 22 can be passed through the through hole 12130 and welded to the groove wall of the second receiving groove 12120 first, and then the cover plate 13 can be welded to the pole post 12 to close the opening of the second receiving groove 12120.

[0206] It should also be noted that the specific configuration of the cover plate 13 is not limited. For example, in some optional embodiments, please refer to... Figure 17 The cover plate 13 includes a first conductive element 131 and a second conductive element 132 made of different materials. The first conductive element 131 is engaged with and electrically connected to the pole post 12, and the second conductive element 132 is engaged with and electrically connected to the first conductive element 131.

[0207] In the above technical solution, the cover plate 13 is configured as a composite form, and the first conductive element 131 is made of the same material as the terminal post 12, thereby facilitating the electrical connection between the first conductive element 131 and the terminal post 12. For example, the first conductive element 131 and the terminal post 12 can be reliably and stably connected by welding. Furthermore, since the second conductive element 132 is made of a different material than the first conductive element 131, it is convenient to use the second conductive element 132 to make electrical connections with busbar components made of a different material than the terminal post 12. For example, the second conductive element 132 can be reliably and stably connected with busbar components made of the same material as the second conductive element 132 by welding.

[0208] For example, when the terminal 12 is the negative terminal 12, and the terminal 12 is a copper terminal and the busbar component is an aluminum sheet, the first conductive element 131 can be made of copper and the second conductive element 132 can be made of aluminum. In this case, the terminal 12 and the first conductive element 131 are made of the same material, allowing for effective welding, and the second conductive element 132 is also made of the same material as the busbar component, enabling effective indirect electrical connection between the terminal 12 and the busbar component via the cover plate 13. Furthermore, the copper-to-copper welding of the terminal 12 and the first conductive element 131 has good fluidity, is less prone to cracking, and helps improve the sealing effect at the weld.

[0209] Please refer to this again. Figure 17In some alternative examples, the first conductive element 131 is located between the second receiving tank 12120 and the second conductive element 132. In the above technical solution, since the first conductive element 131 is located between the second receiving tank 12120 and the second conductive element 132, the second receiving tank 12120 and the second conductive element 132 can be separated. Thus, when the electrolyte in the housing 11 enters the second receiving tank 12120 through the perforation 12130, the first conductive element 131 can be used to prevent this part of the electrolyte from contacting the second conductive element 132, thereby solving the problem of electrolyte corrosion of the second conductive element 132.

[0210] It is worth noting that the cooperation method between the first conductive element 131 and the second conductive element 132 is not limited. For example, in some embodiments, please refer to... Figure 17 The first conductive element 131 has a second groove 1311, and the second conductive element 132 is embedded in the second groove 1311. The opening of the second groove 1311 is formed on the surface of the first conductive element 131 on the side away from the second receiving groove 12120, so that the second conductive element 132 is exposed through the opening of the second groove 1311. Alternatively, in other embodiments, the connection method of the first conductive element 131 and the second conductive element 132 can also be a fastening connection, snap-fit, etc.

[0211] It should also be noted that the "exposed" in the phrase "the second conductive element 132 is exposed by the groove opening of the second groove 1311" means that the first conductive element 131 does not obstruct the second conductive element 132 at the groove opening position of the second groove 1311. It is not required that the second conductive element 132 protrude from the groove opening of the second groove 1311. For example, the second conductive element 132 can be flush with the surface of the first conductive element 131 on the side away from the second receiving groove 12120, or the second conductive element 132 can protrude from the surface of the first conductive element 131 on the side away from the second receiving groove 12120.

[0212] In the above technical solution, on the one hand, by embedding the second conductive element 132 within the first conductive element 131, the assembly difficulty of the first conductive element 131 and the second conductive element 132 can be reduced, the stability and convenience of the cooperation between the first conductive element 131 and the second conductive element 132 can be improved, and the thickness of the cover plate 13 can be reduced, thus reducing the space occupied by the cover plate 13 and improving the space utilization rate of the battery cell 10. On the other hand, since the second conductive element 132 can be exposed from the surface of the first conductive element 131 away from the second receiving groove 12120 through the slot of the second groove 1311, it is beneficial to realize the electrical connection between the second conductive element 132 and the busbar component outside the terminal post 12.

[0213] Furthermore, since the opening of the second groove 1311 is formed on the surface of the first conductive member 131 on the side away from the second receiving groove 12120, it means that the second groove 1311 is open in the direction away from the active material coating portion 21. As a result, the portion of the first conductive member 131 that defines the groove wall of the second groove 1311 is located between the second receiving groove 12120 and the second conductive member 132, thereby separating the second receiving groove 12120 and the second conductive member 132, thereby preventing the electrolyte entering the second groove 1311 from contacting the second conductive member 132 and reducing electrolyte leakage.

[0214] Of course, in other embodiments, the cover plate 13 may not be a composite form composed of multiple materials. For example, in other embodiments of this application, the cover plate 13 may be set as a non-composite form made of the same material, for example, to adapt to the positive electrode post 12, which will not be elaborated here.

[0215] Please refer to this again. Figure 17 The cover plate 13 is also embedded in the opening of the second receiving groove 12120. In the above technical solution, by embedding the cover plate 13 in the second receiving groove 12120, the assembly difficulty of the cover plate 13 and the pole post 12 can be reduced, the assembly stability of the cover plate 13 and the pole post 12 can be improved, as well as the reliability and convenience of the connection, and the space occupied by the cover plate 13 outside the pole post 12 can be reduced. Moreover, since the cover plate 13 is embedded in the opening of the second receiving groove 12120, the second receiving groove 12120 can have sufficient space to accommodate the electrode ear 22.

[0216] Of course, in other embodiments of this application, the way the cover plate 13 and the pole post 12 are matched is not limited to being embedded in the second receiving groove 12120. The cover plate 13 can also be directly covered on the outside of the pole post 12, that is, directly covered on the opening of the second receiving groove 12120, so as to facilitate matching with the current collection component of the battery 100. This embodiment does not limit this.

[0217] In some embodiments, the housing 11 includes a cover 112 and a body 111, the body 111 having an opening 1110, the cover 112 covering the opening 1110, and a pole post 12 provided on the wall of the cover 112 and / or the body 111 opposite to the opening 1110.

[0218] For example, all the terminals 12 can be located on the cover 112. For example, one terminal 12 can be located on the cover 112, while the remaining terminals 12 can be located on the body 111. Since the cover 112 is relatively small, the size of the mold or fixture can be reduced, which helps to reduce costs.

[0219] Of course, at least one terminal post 12 can also be provided on the wall of the housing 111 opposite to the opening 1110. In this way, the electrode assembly 2 enters the housing 111 through the opening 1110, and the tab 22 is directly opposite the terminal post 12, which makes it easier for the tab 22 to connect with the terminal post 12 and improves the assembly efficiency of the battery cell 10.

[0220] Please refer to this again. Figure 2 According to some embodiments of this application, this application also provides a battery 100. The battery 100 includes the battery cell 10 described in any of the above embodiments.

[0221] In the technical solution of this application embodiment, by using the above-mentioned battery cell 10, it is beneficial to increase the capacity of the battery 100, improve the reliability of the battery 100, and reduce the production difficulty.

[0222] Please refer to this again. Figure 1 According to some embodiments of this application, this application also provides an electrical device 1000.

[0223] The electrical device 1000 includes a battery cell 10 as described in any of the above embodiments, or includes a battery 100 as described in the above embodiments, and the battery 100 is used to provide electrical energy to the electrical device 1000. The electrical device 1000 can be any of the aforementioned devices or systems that use the battery 100.

[0224] In the technical solution of this application embodiment, by using the above-mentioned battery 100, the reliability of the power device 1000 can be improved.

[0225] Please refer to this again. Figures 8-14 and further refer to Figure 24 , Figure 24 This is a flowchart illustrating the fabrication process of electrode assembly 2 according to some embodiments of this application. This application provides a method for fabricating electrode assembly 2.

[0226] The preparation method of electrode assembly 2 includes the following steps:

[0227] Provide the incoming materials for electrode assembly 2;

[0228] Multiple tabs 221 of the electrode assembly 2 are stacked;

[0229] The overlapping area Z1 of multiple tabs 221 is welded to form the first welded portion 2211 of the tab portion 22;

[0230] The misaligned areas Z2 of multiple tabs 221 are welded to form a second welded portion 2212 of the tab portion 22. The second welded portion 2212 is located at the end of the first welded portion 2211 away from the active material coating portion 21.

[0231] Specifically, it is possible to first weld the overlapping area Z1 to form a first welded part 2211, and then weld the part of the misaligned area Z2 away from the active material coating part 21 to form a second welded part 2212; or it is possible to first weld the part of the misaligned area Z2 away from the active material coating part 21 to form a second welded part 2212, and then weld the overlapping area Z1 to form a first welded part 2211.

[0232] In the technical solution of this application embodiment, by welding the overlapping area Z1 of multiple tabs 221 to form a first welding part 2211, and welding the misaligned area Z2 of multiple tabs 221 away from the active material coating part 21 to form a second welding part 2212, the area of ​​the welding region of multiple tabs 221 can be increased. On the one hand, the utilization rate of the tab 22 is improved, which is conducive to increasing the capacity of the battery cell 10 and reducing the overcurrent temperature rise. On the other hand, when the tab 22 is welded to the terminal post 12, the second welding part 2212 can better support the welding nozzle compared to the fluffy multiple tabs, reducing the welding defects caused by the welding nozzle pressing into the fluffy area of ​​the multiple tabs 221 in related technologies, reducing the cutting requirements of the welded tab 22, saving costs, and improving the fast charging performance of the battery cell 10.

[0233] Please refer to this again. Figures 8-11 The overlapping area Z1 of multiple tabs 221 is welded, including: sandwiching the overlapping area Z1 of multiple tabs 221 between the first ultrasonic welding seat 81 and the first ultrasonic welding head 82, so as to weld the overlapping area Z1 of the tab 22 to form the first welding part 2211 of the tab 22 by ultrasonic welding.

[0234] Specifically, after the multiple tabs 221 are paired, the multiple tabs 221 are stacked. The stacked multiple tabs 221 have an overlapping area Z1 and a misaligned area Z2. The overlapping area Z1 is sandwiched between the first ultrasonic welding seat 81 and the first ultrasonic welding head 82. Friction occurs between any two adjacent tabs 221 and they melt, thereby welding the multiple tabs 221 together in the overlapping area Z1 to form the first welded part 2211.

[0235] In the above technical solution, since the first welding part 2211 is formed by ultrasonic welding, the welding speed and welding efficiency can be improved, the surface quality of the overlapping area Z1 after welding can be improved, the welding process is clean, stable and reliable, and the energy consumption is low.

[0236] Please refer to this again. Figures 12-14The process of welding the misaligned areas Z2 of multiple tabs 221 includes: sandwiching the misaligned areas Z2 of multiple tabs 221 between the second ultrasonic welding seat 91 and the second ultrasonic welding head 92, so as to weld the misaligned areas Z2 of the tab 22 to form the second welding part 2212 of the tab 22 by ultrasonic welding.

[0237] Specifically, the misaligned region Z2, located away from the active material coating part 21, is sandwiched between the second ultrasonic welding base 91 and the second ultrasonic welding head 92. Friction occurs between any two adjacent tabs 221, causing them to melt. This welds multiple tabs 221 together at the misaligned region Z2, located away from the active material coating part 21, thereby forming the second welding part 2212.

[0238] In the above technical solution, since the second welding part 2212 is formed by ultrasonic welding, the welding speed and welding efficiency can be improved, the surface quality of the overlapping area Z1 after welding can be improved, the welding process is clean, stable and reliable, and the energy consumption is low.

[0239] Please refer to this again. Figures 12-14 One of the surfaces of the second ultrasonic welding base 91 and the second ultrasonic welding head 92 extends along the height of the tab 22, and the other of the surfaces of the second ultrasonic welding base 91 and the second ultrasonic welding head 92 is inclined relative to the height direction of the tab 22.

[0240] In other words, the first surface 2214 of the second welded part 2212 formed after welding can be flush with the first welded part 2211. When welding the tab 22 and the pole post 12, a larger welding nozzle can be used so that part of the welding nozzle can be pressed on the first welded part 2211 and another part can be pressed on the second welded part 2212. That is, the first welded part 2211 and the second welded part 2212 can support the welding nozzle at the same time. This not only reduces the welding difficulty, but also reduces the welding defects caused by the welding nozzle pressing onto the loose area of ​​multiple tabs in related technologies. It also reduces the cutting requirements of the tab after welding, saves costs, and improves the fast charging performance of the battery cell 10.

[0241] In the above technical solution, by using the second ultrasonic welding seat 91 and the second ultrasonic welding head 92, ultrasonic welding can be performed on the misaligned area Z2 to form a preset second welding part 2212. On the one hand, it is convenient to decide whether to cut it according to the needs, thus improving the convenience of cutting. On the other hand, it can reduce the welding difficulty, reduce welding defects, and improve the welding quality.

[0242] In some embodiments, the included angle α between the surfaces of the second ultrasonic welding base 91 and the second ultrasonic welding head 92 facing each other is smaller than the included angle β between the two opposing wall surfaces of the misaligned region Z2. This arrangement allows the second ultrasonic welding base 91 and the second ultrasonic welding head 92 to clamp the portion of the misaligned region Z2 away from the active material coating portion 21, thereby improving welding quality.

[0243] Specifically, after welding the overlapping area Z1 to form the first welded part 2211, the second ultrasonic welding seat 91 and the second ultrasonic welding head 92 can be used to weld the part of the misaligned area Z2 away from the active material coating part 21 together to form the second welded part 2212. Then, it can be selected whether to cut the second welded part 2212 as needed. Then, the welding slag on the cross-section can be removed by means of brushing or vacuuming.

[0244] In other embodiments, the misaligned region Z2 after the multiple tabs 221 are stacked includes an end misaligned region Z21, which is located at the end of the overlapping region Z1 away from the active material coating portion 21. Before welding the end misaligned region Z21 using the second ultrasonic welding socket 91 and the second ultrasonic welding head 92, the method further includes: bending the first part of the end misaligned region Z21 towards the remaining second part of the end misaligned region Z21 in a direction close to the active material coating portion 21, and then stacking and welding them together to form a second welded portion 2212.

[0245] In the above technical solution, by welding the misaligned region Z2 to at least one side of the overlapping region Z1 to form the third welding part 2213, on the one hand, the area of ​​the welding area of ​​the multiple tabs 221 can be increased, the utilization rate of the tab 22 can be improved, which is conducive to increasing the capacity of the battery cell 10 and reducing the overcurrent temperature rise. On the other hand, it can reduce the welding defects caused by the welding nozzle being pressed into the fluffy area of ​​the multiple tabs 221 in the related technology, and it can also facilitate the tab 22 to pass through the perforation on the pole post 12.

[0246] In some embodiments, the method for preparing the electrode assembly 2 further includes: welding the misaligned regions Z2 of a plurality of tabs 221 to form a third welding portion 2213 of the tab portion 22, wherein the third welding portion 2213 is located on at least one side of the first welding portion 2211.

[0247] Specifically, the misaligned region Z2 after the multiple tabs 221 are stacked includes two side misaligned regions Z22, which are located on both sides of the width direction of the overlapping region Z1, and at least one side misaligned region Z22 is welded to form a third welded part 2213.

[0248] In the above technical solution, by welding the misaligned region Z2 to at least one side of the overlapping region Z1 to form the third welding part 2213, on the one hand, the area of ​​the welding area of ​​the multiple tabs 221 can be increased, the utilization rate of the tab 22 can be improved, which is conducive to increasing the capacity of the battery cell 10 and reducing the overcurrent temperature rise. On the other hand, it can reduce the welding defects caused by the welding nozzle being pressed into the fluffy area of ​​the multiple tabs 221 in the related technology, and it can also facilitate the tab 22 to pass through the perforation on the pole post 12.

[0249] Please refer to Figure 17 In some other embodiments, before welding to form the third weld portion 2213, the method further includes: bending a first portion of at least one side misalignment region Z22 toward the remaining second portion of the side misalignment region Z22 in a direction close to the active material coating portion 21, and then stacking and welding them together to form the third weld portion 2213.

[0250] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An electrode assembly, characterized by, The electrode assembly comprises: an active material coating portion; a tab portion connected to the active material coating portion, the tab portion comprising a plurality of tab pieces stacked together, the plurality of tab pieces having an overlapping region and a misaligned region after being stacked together, in a projection plane perpendicular to the thickness direction of the tab pieces, a region where the projections of the plurality of tab pieces completely overlap is defined as the overlapping region, and a region where the projections of the plurality of tab pieces do not completely overlap is defined as the misaligned region, the overlapping region is welded to form a first welding portion, and the misaligned region is welded to form a second welding portion at least at a position away from the active material coating portion.

2. The electrode assembly of claim 1, wherein, The first welding portion and the second welding portion are connected.

3. The electrode assembly according to claim 1, wherein: in the width direction of the tab portion, the width dimension of the first welding portion and the width dimension of the second welding portion are in a proportional range of: 0.8-1.2; and / or, in the width direction of the tab portion, the width dimension of the first welding portion and the width dimension of the tab portion are in a proportional range of: 0.6-1; in the height direction of the tab portion, the height dimension of the second welding portion and the height dimension of the first welding portion are in a proportional range of:

4. The electrode assembly of claim 1, wherein, 0.08-0.2; and / or, 5. The electrode assembly of claim 1, wherein, in the height direction of the tab portion, the height dimension of the first welding portion and the height dimension of the tab portion are in a proportional range of:

6. The electrode assembly of claim 5, wherein, 0.45-0.

65.

7. The electrode assembly of claim 6, wherein, in the height direction of the tab portion, the height dimension of the second welding portion is in a range of:

8. The electrode assembly of claim 6, wherein, 1mm-2mm.

9. The electrode assembly of claim 8, wherein, The thickness of the second welding portion gradually decreases in a direction away from the first welding portion.

10. The electrode assembly of claim 1, wherein, The second welding portion has two oppositely arranged first surfaces and second surfaces, and at least one of the first surfaces and the second surfaces is arranged obliquely with respect to the height direction of the tab portion.

11. The electrode assembly of any one of claims 1-10, wherein, The maximum distance between the first surface and the second surface is in a range of:

12. A battery cell, characterized by 0.5mm-1mm. The first surface extends in the height direction of the tab portion, the second surface is arranged obliquely with respect to the height direction of the tab portion, and the distance between the first surface and the second surface gradually decreases in a direction away from the first welding portion. The included angle between the first surface and the second surface is in a range of:

13. The battery cell of claim 12, wherein, 10°-45°.

14. The battery cell of claim 13, wherein, The first welding portion and the second welding portion are respectively formed by ultrasonic welding. The misaligned region is welded to form a third welding portion on at least one side of the overlapping region. The electrode assembly comprises: a housing provided with a pole; an electrode assembly arranged in the housing, the tab portion being connected to the pole, and the electrode assembly being according to any one of claims 1-11. The pole is provided with a receiving portion, and at least part of the tab portion extends into the receiving portion and is welded to the pole. The receiving portion comprises a first receiving groove, a surface of the pole towards the active material coating portion is a pole inner end face, and a groove opening of the first receiving groove is formed on the pole inner end face, and at least part of the tab portion is accommodated in the first receiving groove.

15. The battery cell of claim 13, wherein, The accommodation portion includes a second accommodation groove, a surface of the pole post distal to the active material coated portion is a pole post outer end surface, a groove opening of the second accommodation groove is formed on the pole post outer end surface, the second accommodation groove is in communication with the interior of the shell through a through hole, and the tab portion is threaded through the through hole and at least partially accommodated in the second accommodation groove.

16. The battery cell of claim 12, wherein, The shell includes a shell cover and a shell body having an opening, the shell cover covers the opening, and the pole post is arranged on a wall opposite to the opening of the shell cover and / or the shell body.

17. A battery, characterized by The battery includes the battery cell according to any one of claims 12-16.

18. An electrical device, comprising: The battery includes the battery according to claim 17.

19. A method of making an electrode assembly, characterized by, The method includes the following steps: Providing a raw material of an electrode assembly; Stacking a plurality of tab pieces of the electrode assembly to form a tab portion; Welding an overlapping area of the tab portion to form a first welding portion; Welding a misaligned area of the tab portion to form a second welding portion, the second welding portion being located at an end of the first welding portion distal to the active material coated portion; In a projection plane perpendicular to a thickness direction of the tab piece, an area where projections of the plurality of tab pieces completely overlap is set as the overlapping area, and an area where the projections of the plurality of tab pieces do not completely overlap is set as the misaligned area.

20. The method of claim 19, wherein the electrode assembly is prepared by The welding of the overlapping area of the tab portion includes: Clamping the overlapping area of the tab portion between a first ultrasonic welding seat and a first ultrasonic welding head to weld the overlapping area of the tab portion in an ultrasonic welding manner to form the first welding portion.

21. The method of claim 19, wherein the electrode assembly is prepared by, The welding of the misaligned area of the tab portion includes: Clamping the misaligned area of the tab portion between a second ultrasonic welding seat and a second ultrasonic welding head to weld the misaligned area of the tab portion in an ultrasonic welding manner to form the second welding portion.

22. The method of claim 21, wherein the electrode assembly is prepared by: One of the surfaces of the second ultrasonic welding seat and the second ultrasonic welding head facing each other extends along a height of the tab portion, and the other is arranged to be inclined relative to the height direction of the tab portion.

23. The method of claim 21 or 22, wherein the electrode assembly is prepared by a method comprising: An included angle between the surfaces of the second ultrasonic welding seat and the second ultrasonic welding head facing each other is smaller than an included angle of two oppositely arranged wall surfaces of the misaligned area.

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