Electrode assembly and its manufacturing method, battery cell, battery, and power consumption device

Abstract

The present invention relates to an electrode assembly and a method for manufacturing the same, a battery cell, a battery, and a power consumption device. The electrode assembly includes an active material coated portion and a plurality of stacked tab pieces, the stacked tab pieces having overlapping regions and misaligned regions, a tab portion formed by welding the overlapping region to form a first weld, and a tab portion formed by welding at least the portion of the misaligned region away from the active material coated portion. In the technical solution of the embodiment of the present invention, on the one hand, it is advantageous to increase the utilization rate of the tab portion, improve the capacity of the battery cell, and suppress the temperature rise during overcurrent. On the other hand, the second weld can play a role in supporting the welding press nozzle more than the bulging plurality of tab pieces, reducing the problem of welding defects, relaxing the cutting requirements of the tab portion after welding to save costs, improving the rapid charging performance and assembly efficiency of the battery cell, and the tab portion can be made less susceptible to damage by the hole walls of the through-hole structure.

Description

【Technical Field】 【0001】 Cross - reference to Related Applications This application claims the priority of the Chinese patent application with application number 202311413781.2 and filing date October 27, 2023, and the disclosure content of the Chinese patent application is incorporated herein by reference in its entirety. 【0002】 This application relates to the field of batteries, and specifically, to electrode assemblies and their manufacturing methods, battery cells, batteries, and power - consuming devices. 【Background Art】 【0003】 Energy conservation and emission reduction are key points in the sustainable development of the automotive industry. Electric vehicles, due to their advantages of energy conservation and environmental friendliness, have become an important component in the sustainable development of the automotive industry. For electric vehicles, battery technology is an important factor related to their development. In the prior art, due to the low utilization rate of the tab part of the electrode assembly, the capacity of the battery cell decreases. 【Summary of the Invention】 【Means for Solving the Problems】 【0004】 In view of the above problems, this application provides an electrode assembly and its manufacturing method, a battery cell, a battery, and a power - consuming device that can improve the utilization rate of the tab part of the electrode assembly and increase the capacity of the battery cell. 【0005】 According to a first aspect, this application provides an electrode assembly, which includes an active - material coating part and a tab part connected to the active - material coating part, the tab part includes a plurality of stacked tab pieces, the plurality of stacked tab pieces have an overlapping region and a displaced region, the overlapping region is welded to form a first welded part, and at least a part of the displaced region away from the active - material coating part is welded to form a second welded part. 【0006】 In the technical solution according to the embodiment of the present application, the area of ​​the welding region of the multiple tab pieces can be increased by welding the overlapping regions of the multiple tab pieces to form a first weld and welding the portion of the misaligned region of the multiple tab pieces that is away from the active material coated portion to form a second weld. On the one hand, this is advantageous in increasing the utilization rate of the tab portion, improving the capacity of the battery cell, and suppressing temperature rise during overcurrent. On the other hand, when welding the tab portion to the electrode terminal, the second weld can support the welding press nozzle more than the multiple bulging tab pieces, and there are no problems such as wrinkle formation, so the problem of welding defects caused by the welding press nozzle being pressed against the bulging region of the multiple tab pieces, as seen in the prior art, can be reduced, and the cutting requirements of the tab portion after welding can be relaxed, saving costs, while also improving the rapid charging performance of the battery cell. Furthermore, by welding the misaligned region to form the second weld, it is possible to improve the efficiency of passing the tab portion through the through-hole structure, thereby improving the assembly efficiency of the battery cell, and making the tab portion less susceptible to damage from the hole walls of the through-hole structure. 【0007】 In some embodiments, the first weld is provided connected to the second weld. In the above technical solution, the first and second welds, provided connected to the multiple bulging tab pieces, improve the rigidity of the multiple tab pieces after welding to some extent. This makes the tab pieces less susceptible to damage from the hole walls of the through-hole structure and improves the efficiency of passing the tab pieces through the through-hole structure. At the same time, the second weld formed by welding is less likely to collapse even when subjected to pressure relative to the first weld, can reliably support the welding press nozzle, and does not cause problems such as wrinkle formation. Therefore, it is possible to reduce the problem of welding defects caused by the welding press nozzle being pressed against the bulging areas of the multiple tab pieces, as seen in the prior art. 【0008】 In some embodiments, the ratio of the width size of the first weld to the width size of the second weld along the width direction of the tab portion is in the range of 0.8 to 1.2, and / or the ratio of the width size of the first weld to the width size of the tab portion along the width direction of the tab portion is in the range of 0.6 to 1, the ratio of the height size of the second weld to the first weld along the height direction of the tab portion is in the range of 0.08 to 0.2, and / or the ratio of the height size of the first weld to the tab portion along the height direction of the tab portion is in the range of 0.45 to 0.65. In the above technical solution, the area of ​​the welding region of multiple tab pieces can be widened, the utilization rate of the tab portion can be increased, which is advantageous in improving the capacity of the battery cell and suppressing temperature rise during overcurrent, and the problem of welding defects occurring when the welding press nozzle is pressed against the bulging region of multiple tab pieces, as seen in the prior art, can be reduced. 【0009】 In some embodiments, the height of the second weld is 1 mm to 2 mm along the height direction of the tab portion. In the above technical solution, by limiting the height of the second weld to satisfy the above conditions, on the one hand, the occupancy rate of the misaligned area of ​​the multiple tab pieces is reduced as much as possible, improving the yield rate of electrode assemblies and contributing to the improvement of battery cell quality. On the other hand, assuming that misalignment occurs in the multiple tab pieces, the area of ​​the welded area of ​​the multiple tab pieces is widened by welding the misaligned area, thereby reducing the problem of welding defects caused by the welding press nozzle being pressed against the bulging area of ​​the multiple tab pieces, as seen in the prior art. 【0010】 In some embodiments, the thickness of the second weld gradually decreases in the direction away from the first weld. This makes cutting easier. 【0011】 In some embodiments, the second weld has two opposing first and second surfaces, and at least one of the first and second surfaces is inclined with respect to the height direction of the tab portion. In the above technical solution, by forming the second weld in the above form, it is possible to easily determine whether or not cutting is necessary in subsequent processes, thereby improving the convenience of the cutting work. 【0012】 In some embodiments, the maximum distance between the first surface and the second surface is 0.5 mm to 1 mm. In the above technical solution, by limiting the maximum distance between the first surface and the second surface to within the above range, on the one hand, it is possible to easily determine whether or not cutting is necessary in subsequent processes, thereby improving the convenience of the cutting work, and on the other hand, it is possible to reduce the difficulty of welding, suppress welding defects, and improve welding quality. 【0013】 In some embodiments, the first surface extends along the height direction of the tab portion, the second surface is provided at an inclination with respect to the height direction of the tab portion, and the distance between the first surface and the second surface gradually decreases in the direction away from the first weld. In the above technical solution, by forming the second weld in the above form, on the one hand, it is possible to easily determine whether or not cutting is necessary in subsequent processes, thereby improving the convenience of cutting work, and on the other hand, it is possible to reduce the difficulty of welding, suppress welding defects, and improve welding quality. 【0014】 In some embodiments, the angle between the first surface and the second surface is 10° to 45°. This allows the portion of the displacement area that is further away from the active material coating to be easily welded using an ultrasonic stamp and an ultrasonic welding horn, thereby improving the convenience and quality of welding. 【0015】 In some embodiments, the first and second welds are formed using ultrasonic welding. This improves welding speed and efficiency, and enhances the surface quality after welding. Furthermore, the welding process is clean, stable, and reliable, and energy consumption is reduced. 【0016】 In some embodiments, the displacement region is located on at least one side of the overlapping region and is welded to form a third weld. In the above technical solution, by having the displacement region located on at least one side of the overlapping region and welded to form a third weld, on the one hand, the area of ​​the welded region of the multiple tab pieces can be increased, the utilization rate of the tab portion can be increased, which is advantageous in improving the capacity of the battery cell and suppressing temperature rise during overcurrent, and on the other hand, the problem of welding defects occurring when the welding press nozzle is pressed against the bulging region of the multiple tab pieces, as seen in the prior art, can be reduced, and the tab portion can easily pass through the through hole at the electrode terminal. 【0017】 According to a second aspect, the present invention provides a battery cell comprising a housing and an electrode assembly, wherein the housing is provided with electrode terminals, the electrode assembly is provided within the housing, the tab portion is connected to the electrode terminals, and the electrode assembly is one of the electrode assemblies of the above embodiment. 【0018】 According to the technical solution of the embodiment of the present invention, by applying the above electrode assembly, it is advantageous on the one hand to increase the utilization rate of the tab portion, improve the capacity of the battery cell, and suppress the temperature rise during overcurrent. On the other hand, when welding the tab portion and the electrode terminal, the second weld portion can play a role in supporting the welding press nozzle more than the multiple bulging tab pieces, and there are no problems such as wrinkle formation, so it is possible to reduce the problem of welding defects caused by the welding press nozzle being pressed against the bulging areas of the multiple tab pieces, as seen in the prior art, thereby improving the reliability of the battery cell in use, relaxing the cutting requirements of the tab portion after welding, reducing the difficulty of manufacturing the battery cell, saving costs, and improving the rapid charging performance of the battery cell. 【0019】 In some embodiments, the electrode terminal is provided with a housing, and at least a portion of the tab is inserted into the housing and welded to the electrode terminal. The hollow structure of the housing can reduce the weight of the electrode terminal to some extent, improving the gravimetric energy density of the battery cell and the battery. At the same time, since the tab can be housed within the housing, the assembly efficiency of the tab is improved, the space occupied by the tab is reduced, and the internal space of the battery cell can be fully utilized. As a result, both the fitting between the holder and the electrode terminal and the fitting between the holder and the tab are tighter and more reliable, making the structure of the battery cell more compact and further advantageous in improving the energy density of the battery cell. 【0020】 In some embodiments, the housing portion includes a first housing groove, the surface of the electrode terminal facing the active material coating portion is the inner end face of the electrode terminal, the groove opening of the first housing groove is formed on the inner end face of the electrode terminal, and at least a portion of the tab portion is housed in the first housing groove. In the above technical solution, on the one hand, by providing a first housing groove in the electrode terminal, the weight of the electrode terminal can be reduced to some extent, and the gravimetric energy density of the battery cell and battery can be improved. On the other hand, since the groove opening of the first housing groove is formed on the inner end face of the electrode terminal, which is the surface of the electrode terminal closer to the active material coating portion, the first housing groove opens toward the direction of the active material coating portion, and the tab portion can be easily inserted into the first housing groove, thereby improving assembly efficiency. Therefore, this type of first housing groove is easy to process and improves manufacturing efficiency. 【0021】 In some embodiments, the housing portion includes a second housing groove, the surface of the electrode terminal away from the active material coating portion is the outer end surface of the electrode terminal, the groove opening of the second housing groove is formed on the outer end surface of the electrode terminal, the second housing groove communicates with the inside of the housing through a through hole, and the tab portion is arranged with a through hole and at least a part of it is housed in the second housing groove. In the above technical solution, on the one hand, by providing the second housing groove on the electrode terminal, the weight of the electrode terminal can be reduced to some extent, and the gravimetric energy density of the battery cell and battery can be improved. On the other hand, since the groove opening of the second housing groove is formed on the outer end surface of the electrode terminal, and the outer end surface of the electrode terminal is the surface away from the active material coating portion of the electrode terminal, the second housing groove opens in a direction away from the active material coating portion. This makes it easier to organize and store the tab portion through the groove opening of the second housing groove when at least a portion of the tab portion is housed in the second housing groove, and also makes it easier to perform electrical connection operations between the tab portion and the electrode terminals through the groove opening of the second housing groove, thereby reducing the difficulty of manufacturing battery cells and improving the manufacturing efficiency of battery cells. 【0022】 In some embodiments, the housing includes a housing cover and a housing body having an opening, the housing cover is placed over the opening, and electrode terminals are provided on the wall of the housing cover and / or housing body facing the opening. By providing the electrode terminals on the housing and having a relatively small housing cover, the size of the mold and jig can be reduced, which is advantageous for cost reduction. By providing the electrode terminals on the wall of the housing body facing the opening, the electrode assembly is inserted into the housing body along the opening, and the tab portion faces the electrode terminal, making connection between the tab portion and the electrode terminal relatively easy and improving the assembly efficiency of the battery cell. 【0023】 According to a third aspect, the present application provides a battery including a battery cell according to any one of the above embodiments. 【0024】 In the technical solution of the embodiment of the present invention, applying the above-mentioned battery cell is advantageous in improving the battery capacity, enhancing the reliability of the battery's operation, and reducing the difficulty of manufacturing. 【0025】 According to the fourth aspect, the present application provides a power consumption device including the battery according to any one of the above embodiments. 【0026】 In the technical solution according to the embodiment of the present application, by applying the above battery, the use reliability of the power consumption device can be improved. 【0027】 According to the fifth aspect, the present application provides a method for manufacturing an electrode assembly, the method including the steps of: providing raw materials for the electrode assembly; stacking and providing a plurality of tab pieces of the electrode assembly; welding an overlapping area of the plurality of tab pieces to form a first welded portion of the tab portion; and welding a displacement area of the plurality of tab pieces to form a second welded portion of the tab portion, the second welded portion being located at one end away from the active material coating portion of the first welded portion. 【0028】 In the technical solution according to the embodiment of the present application, by welding the overlapping area of the plurality of tab pieces to form the first welded portion and welding a portion of the displacement area of the plurality of tab pieces away from the active material coating portion to form the second welded portion, the area of the welding region of the plurality of tab pieces can be increased. On the one hand, it is beneficial to improve the utilization rate of the tab portion, improve the capacity of the battery cell, and suppress the temperature rise during overcurrent. On the other hand, when welding the tab portion and the pole terminal, the second welded portion can play a role in supporting the welding press nozzle rather than the plurality of bulged tab pieces, reducing the problem of welding defects caused by the welding press nozzle being pressed against the bulging area of the plurality of tab pieces as seen in the prior art. Also, while relaxing the cutting requirements of the tab portion after welding to save costs, the rapid charging performance of the battery cell can also be improved. 【0029】 In some embodiments, the step of welding the overlapping area of the plurality of tab pieces includes sandwiching the overlapping area of the plurality of tab pieces between a first ultrasonic welding anvil and a first ultrasonic welding horn, and welding the overlapping area of the tab portion by an ultrasonic welding method to form a first welded portion. In the above technical solution, since the first welded portion is formed by an ultrasonic welding method, the welding speed and welding efficiency are improved, and the surface quality after welding of the overlapping area is improved. Furthermore, the welding process is clean, stable, highly reliable, and the energy consumption is also reduced. 【0030】 In some embodiments, the step of welding the displacement area of the plurality of tab pieces includes sandwiching the displacement area of the plurality of tab pieces between a second ultrasonic welding anvil and a second ultrasonic welding horn, and welding the displacement area of the tab portion by an ultrasonic welding method to form a second welded portion. In the above technical solution, since the second welded portion is formed by an ultrasonic welding method, the welding speed and welding efficiency are improved, and the surface quality after welding of the overlapping area is improved. Furthermore, the welding process is clean, stable, highly reliable, and the energy consumption is also reduced. 【0031】 In some embodiments, one of the opposing surfaces of the second ultrasonic welding anvil and the second ultrasonic welding horn extends along the height direction of the tab portion, and the other is provided inclined with respect to the height direction of the tab portion. In the above technical solution, by applying the second ultrasonic welding anvil and the second ultrasonic welding horn, ultrasonic welding can be performed on the displacement area. Thereby, a predetermined second welded portion is formed. On the one hand, it is possible to easily determine whether cutting is required in subsequent processes, improving the convenience of the cutting operation. On the other hand, the difficulty of welding can be reduced, welding defects can be suppressed, and the welding quality can be improved. 【0032】 In some embodiments, the angle between the opposing surfaces of the second ultrasonic welding anvil and the second ultrasonic welding horn is smaller than the angle between the two opposing wall surfaces provided in the displacement area. By setting it in this way, the second ultrasonic welding anvil and the second ultrasonic welding horn can surely sandwich the portion away from the active material coating portion of the displacement area, and the welding quality can be improved. 【0033】 The above description is merely an outline of the technical solution of this application. In order to understand the technical solution of this application more clearly, and to enable a clearer understanding of the above and other objectives, features, and advantages of this application, specific embodiments of this application are given below, which can be implemented in accordance with the contents of the specification. [Brief explanation of the drawing] 【0034】 For those skilled in the art, various other advantages and effects will become clear by reading the detailed description of the preferred embodiments below. The drawings are intended to illustrate preferred embodiments and should not be considered limiting. In the drawings, the same components are given the same reference numerals. The drawings are as follows. 【0035】 [Figure 1] This is a schematic diagram of the structure of a vehicle according to several embodiments of the present invention. [Figure 2] This is an exploded view of the structure of a battery according to several embodiments of the present invention. [Figure 3] This is a perspective view of a battery cell according to some embodiments of the present application. [Figure 4] This is a cross-sectional view of the structure of a battery cell according to several embodiments of the present application. [Figure 5] This is a localized enlarged view of an electrode assembly according to several embodiments of the present application. [Figure 6] This is a side view of an electrode assembly according to some embodiments of the present application. [Figure 7] Figure 6 is a localized magnified view of the electrode assembly shown. [Figure 8] This is a schematic diagram of the structure of the tab portion of an electrode assembly according to some embodiments of the present application before it is paired. [Figure 9] This is a schematic diagram of the structure of the first ultrasonic welding anvil and the first ultrasonic welding horn after the tab portions of the electrode assembly according to some embodiments of the present application have been paired. [Figure 10]This is a schematic diagram of the structure of the first ultrasonic welding anvil and the first ultrasonic welding horn before the overlapping region of the tab portion of the electrode assembly according to some embodiments of the present application is welded. [Figure 11] This is a schematic diagram of the structure of an electrode assembly according to some embodiments of the present invention, in which the overlapping region of the tab portion is welded with ultrasound to form a first welded portion. [Figure 12] This is a schematic diagram of the structure of the second ultrasonic welding anvil and the second ultrasonic welding horn before the misaligned region of the tab portion of the electrode assembly according to some embodiments of the present application is welded. [Figure 13] This is a schematic diagram of the structure of an electrode assembly according to some embodiments of the present invention, in which a second welded portion is formed by ultrasonic welding in the displacement region of the tab portion away from the active material coated portion. [Figure 14] This is a schematic diagram of the structure of an electrode assembly according to some embodiments of the present application. [Figure 15] This is a localized enlarged view of an electrode assembly according to some other embodiments of the present application. [Figure 16] This is a plan view of an electrode assembly according to some other embodiments of the present application. [Figure 17] This is a schematic cross-sectional view of the tab portion of an electrode assembly according to yet another embodiment of the present application. [Figure 18] This is a schematic diagram of a local cross-section of a battery cell according to some embodiments of the present application. [Figure 19] This is a schematic diagram of a local cross-section of a battery cell according to some embodiments of the present application. [Figure 20] This is a schematic diagram of a local cross-section of a battery cell according to some embodiments of the present application. [Figure 21] This is a schematic diagram of a local cross-section of a battery cell according to some embodiments of the present application. [Figure 22] This is a schematic diagram of a local cross-section of a battery cell according to some embodiments of the present application. [Figure 23] This is a schematic diagram of a local cross-section of a battery cell according to some embodiments of the present application. [Figure 24] This is a manufacturing flowchart of an electrode assembly according to several embodiments of the present invention. [Modes for carrying out the invention] 【0036】 The following examples of embodiments of the technical solution of the present application will be described in detail with reference to the drawings. The following embodiments are used solely to provide a clearer explanation of the technical solution of the present application and are merely examples; they do not limit the scope of protection of the present application. 【0037】 Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which this application pertains, and the terms used herein are intended solely to describe specific embodiments and are not intended to limit this application. The terms “including” and “having” and their synonyms in the description and claims of this application and in the description of the drawings above are intended to be non-exclusive. 【0038】 In the description of the embodiments of this application, terms such as "first," "second," etc., are merely used to distinguish different objects and should not be understood as implicitly indicating the quantity, specific order, or hierarchical relationship of technical features of relative importance, or that which have been shown. In the description of the embodiments of this application, unless otherwise specifically limited, "multiple" means two or more. 【0039】 References to “Examples” in this specification mean that certain features, structures, or properties described in relation to an example may be included in at least one example of the present application. Where the term appears elsewhere in this specification, it does not necessarily refer to the same example, nor does it imply that each example is mutually exclusive, independent, or substitutable with the others. Those skilled in the art will understand, both explicitly and implicitly, that the examples described herein can be combined with other examples. 【0040】 The term "and / or" in the description of the embodiments of this application merely describes the relationship between related objects, indicating that three types of relationships are possible. For example, A and / or B can represent three situations: A existing alone, A and B existing simultaneously, and B existing alone. In this specification, the symbol " / " generally indicates that the preceding and following related objects are in an "or" relationship. 【0041】 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 sets (including two sets), and "multiple sheets" refers to two or more sheets (including two sheets). 【0042】 In the description of the embodiments of this application, the orientations or positional relationships indicated by terms such as "center," "length," "width," "thickness," "top," "bottom," "front," "back," "left," "right," "vertical," "horizontal," "upper part," "bottom," "inside," "outside," "axial direction," "radial direction," and "circumferential direction" are based on the orientations or positional relationships shown in the drawings and are merely intended to facilitate the explanation of the embodiments of this application and to simplify the explanation. They do not indicate or imply that the device or element in question has a specific orientation, or that it should be composed of and operated in a specific orientation, and therefore should not be understood as limiting the embodiments of this application. 【0043】 In the description of the embodiments of this application, unless otherwise specifically defined and limited, terms such as “attached,” “connected,” “connected,” and “fixed” should be understood in a broad sense. For example, they may be fixed connections, detachable connections, or integral connections. They may be mechanical connections or electrical connections. They may be directly connected, indirectly connected via an intermediate medium, or be internal communication between two elements or an interaction relationship between two components. Those skilled in the art will be able to understand the specific meaning of the above terms in the embodiments of this application depending on the specific circumstances. 【0044】 Currently, with the evolving market conditions, the applications of power batteries are expanding rapidly. Power batteries are not limited to applications in energy storage and power systems such as hydroelectric, thermal, wind, and solar power plants, but are also widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in multiple fields such as military equipment and aerospace. As the application fields of power batteries continue to expand, the demand for them in the market is also constantly growing. 【0045】 In conventional technology, the electrode assembly of a battery cell includes multiple stacked tab pieces, which are connected by ultrasonic welding to form the tab portion. However, due to the effects of processing accuracy and tolerances, the stacked tab pieces do not overlap perfectly, resulting in problems such as misalignment. 【0046】 Generally, during the assembly process of a battery cell, the tab portion must first be passed through a through-hole structure, and then the tab portion and the electrode terminal must be welded. Here, the through-hole structure may be the through-hole structure of the electrode terminal itself, or it may be the through-hole structure of the holder located between the electrode terminal and the electrode assembly. Since a misaligned tab portion is relatively bulging, it is prone to interference with the hole wall of the through-hole structure during passage, which not only affects the assembly efficiency of the battery cell but also risks damaging the tab portion. Therefore, before welding the tab portion and the electrode terminal, it is necessary to first cut off the misaligned portion of the tab portion and then press the welding press nozzle against the welding position of the tab portion. Otherwise, if the welding press nozzle is pressed against the bulging area of ​​the tab portion, problems such as welding defects will occur. 【0047】 Furthermore, because the misaligned portion must be cut off before connecting the tab to the electrode terminal, the overall length of the tab becomes shorter, resulting in lower utilization. The size of the welding press nozzle required when welding the tab to the electrode terminal is relatively small, and the length of the weld mark formed by welding the tab to the electrode terminal is relatively short, resulting in a narrow current-carrying area and low current-carrying efficiency. This affects the charge-discharge efficiency of the battery cell and reduces the capacity of the battery cell. 【0048】 Therefore, in the embodiment of the present invention, we propose an electrode assembly in which a first weld is formed by welding the overlapping regions of multiple tab pieces, and a second weld is formed by welding the portion of the misaligned region of the multiple tab pieces that is away from the active material coated area. This configuration makes it possible to increase the area of ​​the welded region of the multiple tab pieces. On the one hand, it is advantageous in increasing the utilization rate of the tab portion, improving the capacity of the battery cell, and suppressing the temperature rise during overcurrent. On the other hand, when welding the tab portion to the electrode terminal, the second weld can play a role in supporting the welding press nozzle more than the multiple bulging tab pieces, and the problem of welding defects occurring when the welding press nozzle is pressed against the bulging region of the multiple tab pieces, as seen in the prior art, can be reduced. Furthermore, it is possible to relax the cutting requirements of the tab portion after welding, saving costs, while also improving the rapid charging performance of the battery cell. 【0049】 The electrode assembly according to the embodiment of the present application is applied to a battery cell, and the battery cell can be used in power consumption devices that use batteries as a power source or in various energy storage systems that use batteries as energy storage elements. Power consumption devices may be, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, battery cars, electric vehicles, ships, spacecraft, etc. Electric toys may include stationary or mobile electric toys such as game consoles, electric car toys, electric boat toys and electric aircraft toys, and spacecraft may include aircraft, rockets, space shuttles and spacecraft, etc. 【0050】 In the following embodiments, for the sake of explanation, the power consumption device 1000 of the embodiment of the present application will be described as a vehicle. 【0051】 Referring to Figure 1, which is a schematic diagram of the structure of a vehicle according to several embodiments of the present application, the vehicle may be a gasoline vehicle, a natural gas vehicle, or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle, or a range extender vehicle, etc. A battery 100 is installed inside the vehicle, and the battery 100 may be installed at the bottom, front, or rear of the vehicle. The battery 100 can be used to supply power to the vehicle, for example, as the operating power source of the vehicle. The vehicle may further 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 for starting the vehicle, navigation, and operating power during driving. 【0052】 In some embodiments of the present invention, the battery 100 can provide driving power to the vehicle not only as an operating power source for the vehicle, but also as a driving power source for the vehicle, by substituting or partially substituting fuel or natural gas. 【0053】 Referring to Figure 2, Figure 2 is an exploded view of a battery 100 according to several embodiments of the present application. The battery 100 includes a housing 20 and a battery cell 10, the battery cell 10 being housed within the housing 20. The housing 20 is used to provide a housing space for the battery cell 10, and the housing 20 can employ various structures. In some embodiments, the housing 20 may include a first housing 201 and a second housing 202, the first housing 201 and the second housing 202 overlap each other, and both the first housing 201 and the second housing 202 define a housing space for housing the battery cell 10. The second housing 202 may be a hollow structure with one end open 1110, and the first housing 201 may be a plate-like structure, the first housing 201 overlaps the open side of the second housing 202, and both the first housing 201 and the second housing 202 define a housing space. Both the first housing 201 and the second housing 202 may have a hollow structure with one side open, and the open side of the first housing 201 is placed over the open side of the second housing 202. The housing 20 formed from the first housing 201 and the second housing 202 may have various shapes such as a cylinder or a rectangular parallelepiped. 【0054】 In the battery 100, there may be multiple battery cells 10, and the multiple battery cells 10 can be connected in series, in parallel, or in series-parallel. Series-parallel connection means that the multiple battery cells 10 can be connected in both series and parallel. Multiple battery cells 10 can be directly connected in series, in parallel, or in series-parallel, and then the entire assembly composed of multiple battery cells 10 can be housed in the housing 20. In addition, the battery 100 may be configured as a module of multiple battery cells 10, which are first connected in series, in parallel, or in series-parallel, and then the modules of multiple battery cells 100 may be further connected in series, in parallel, or in series-parallel to form a single unit which is then housed in the housing 20. The battery 100 may further include other structures, such as bus members for realizing electrical connections between multiple battery cells 10. 【0055】 Each battery cell 10 may be a secondary battery or a primary battery, and may be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited to these. The battery cell 10 may be cylindrical, flattened, rectangular, or have other shapes. 【0056】 Referring to Figures 3 and 4, Figure 3 is a perspective view of a battery cell 10 according to some embodiments of the present application, and Figure 4 is a structural cross-sectional view of a battery cell 10 according to some embodiments of the present application. The battery cell 10 is the smallest unit that constitutes the battery 100. As shown in Figures 3 and 4, the battery cell 10 includes a housing 11 and an electrode assembly 2, and the housing 11 includes a housing cover 112 and a housing body 111. 【0057】 The housing body 111 has an opening 1110, and the housing cover 112 is a member that covers the opening 1110 and isolates the internal environment of the battery cell 10 from the external environment. The shape of the housing cover 112 can be adapted to the shape of the housing body 111 and fitted together with the housing body 111, but is not limited to these. Optionally, the housing cover 112 can be manufactured from a material having a certain hardness and strength (e.g., an aluminum alloy), which makes the housing cover 112 less prone to deformation even when pressed or struck, allowing the battery cell 10 to have higher structural strength and improved reliability. Functional members such as electrode terminals may be provided on the housing cover 112. The electrode terminals can be electrically connected to the electrode assembly 2 and are used to input and output electrical energy from the battery cell 10. In some embodiments, the housing cover 112 may be further equipped with a pressure reduction mechanism to release internal pressure when the internal pressure or temperature of the battery cell 10 reaches a threshold. The housing cover 112 can be made of any material, such as copper, iron, aluminum, stainless steel, aluminum alloy, or plastic, and the embodiments of this application are not particularly limited thereto. In some embodiments, an insulating member may be provided inside the housing cover 112, which may be used to isolate the electrical connection members in the housing body 111 from the housing cover 112, thereby reducing the risk of short circuits. For example, the insulating member may be made of plastic, rubber, or the like. 【0058】 The housing body 111 is an assembly that fits with the housing cover 112 to form the internal environment of the battery cell 10, and the formed internal environment may be used to house the electrode assembly 2, electrolyte, and other components. The housing body 111 and the housing cover 112 may be separate components, and the housing body 111 may have an opening 1110, at which point the housing cover 112 is placed over the opening 1110 to form the internal environment of the battery cell 10. The housing cover 112 and the housing body 111 may be integrated, and specifically, the housing cover 112 and the housing body 111 may have a common connection surface before other components are placed in the housing, and the housing cover 112 is placed over the housing body 111 when it is necessary to seal the inside of the housing body 111, but is not limited to this. The housing body 111 may have various shapes and dimensions, such as a rectangular parallelepiped, cylinder, or hexagonal prism. Specifically, the shape of the housing body 111 is determined by the specific shape and size of the electrode assembly 2. The housing body 111 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, or plastic, and the embodiments of this application are not particularly limited to these materials. 【0059】 The housing body 111 may contain one or more electrode assemblies 2. The electrode assembly 2 is a component that generates an electrochemical reaction in the battery cell 10, and includes an active material coated portion 21 and a tab portion 22, the tab portion 22 being connected to the active material coated portion 21. The electrode assembly 2 is mainly formed by winding or stacking a positive electrode sheet and a negative electrode sheet, and generally a separator is provided between the positive electrode sheet and the negative electrode sheet. The portions of the positive electrode sheet and the negative electrode sheet containing the active material constitute the active material coated portion 21 of the electrode assembly 2, and the portions of the positive electrode sheet and the negative electrode sheet not containing the active material each constitute the tab portion 22. During the charging and discharging process of the battery 100, the positive electrode active material and the negative electrode active material react with the electrolyte, and the tab portion 22 is connected to the electrode terminals to form a current circuit. 【0060】 The electrode assembly 2 is a component that generates an electrochemical reaction in the battery cell 10. The housing 11 may contain one or more electrode assemblies 2. The electrode assembly 2 includes an active material coated portion 21 and a tab portion 22 connected to the active material coated portion 21. Specifically, the electrode assembly 2 is mainly formed by winding or laminating a positive electrode sheet, a separator, and a negative electrode sheet. The portions of the positive electrode sheet and the negative electrode sheet containing the active material constitute the active material coated portion 21 of the electrode assembly 2, and the portions of the positive electrode sheet and the negative electrode sheet not containing the active material each constitute the tab portion 22. The positive electrode tab portion and the negative electrode tab portion may both be located at one end of the active material coated portion 21, or they may each be located at both ends of the active material coated portion 21. During the charging and discharging process of the battery 100, the positive electrode active material and the negative electrode active material react with the electrolyte, and the tab portion 22 is connected to the electrode terminals (e.g., electrode terminals) to form an electric current circuit. 【0061】 As shown in Figures 3 and 4, the battery cell 10 further includes a holder 3, an insulating member 4, and an explosion-proof valve 6. The holder 3 is provided at one end of the active material coated portion 21, and a through-hole 314 is provided in the holder 3, and the tab portion 22 passes through the through-hole 314 and is connected to the electrode terminal 12. The insulating member 4 is connected to the holder 3 and together covers the electrode assembly 2 in the circumferential direction. The insulating member 4 may also be used to isolate the electrical connection members within the housing 11 from the housing 11, thereby reducing the risk of short circuits. Exemplarily, the insulating member 4 may be plastic, rubber, or the like. The insulating member 4 may be connected to the holder 3 by adhesive, or by heat fusion, and of course, the insulating member 4 and the holder 3 may be further bonded in other ways. The explosion-proof valve 6 is provided in 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 may be provided in the housing cover 112 or in any wall of the housing body 111. 【0062】 According to some embodiments of the present application, referring again to Figure 4 and further to Figure 5, which is a localized enlarged view of an electrode assembly 2 according to some embodiments of the present application. The tab portion 22 of the electrode assembly 2 includes a plurality of stacked tab pieces 221. Due to the influence of the manufacturing method and manufacturing tolerances, precise alignment is difficult after stacking the multiple layers of tab pieces 221, resulting in a phenomenon of edge misalignment. Therefore, in the projection plane perpendicular to the thickness direction of the tab piece 221, the region where the projections of the multiple layers of tab pieces 221 completely overlap is defined as the overlapping region Z1, and the region where the projections of the multiple layers of tab pieces 221 do not completely overlap is defined as the misalignment region Z2. That is, the multiple tab pieces 221 have an overlapping region Z1 and a misalignment region Z2 after stacking. The reason for the misalignment region Z2 is that the electrode assembly 2 is formed by winding or laminating a positive electrode sheet, a separator, and a negative electrode sheet, and during the winding or lamination process of the electrode assembly 2, manufacturing errors prevent the tab pieces 211, which are provided corresponding to the positive electrode sheet or negative electrode sheet of each layer, from being perfectly aligned. 【0063】 Referring further to Figures 6 and 7, Figure 6 is a side view of an electrode assembly 2 according to some embodiments of the present application, and Figure 7 is a localized enlarged view of the electrode assembly 2 shown in Figure 6. By welding the overlapping region Z1 to form a first welded portion 2211, the overlapping region Z1 portions of the multiple tab pieces 221 are integrally welded, and by welding at least the portion of the displacement region Z2 away from the active material coated portion 21 to form a second welded portion 2212, the portions of the displacement region Z2 of the multiple tab pieces 221 away from the active material coated portion 21 are integrally welded. 【0064】 As shown in Figures 5 to 7, the Z direction in Figure 5 is the height direction of the tab portion 22 of the electrode assembly 2, the X direction is the width direction of the tab portion 22 of the electrode assembly 2, and the Y direction in Figures 6 and 7 is the thickness direction of the tab portion 22 of the electrode assembly 2. 【0065】 Generally, before welding the tab portion 22 to the electrode terminal 12, the tab portion 22 must first be cut, and then the welding press nozzle must be pressed against the welding position of the tab portion 22. Otherwise, if the welding press nozzle is pressed against the bulging area of ​​the tab portion 22, problems such as defective welding may occur, and the bulging tab portion 22 may be difficult to pass through the through-hole structure, affecting not only the assembly efficiency of the battery cell 10 but also making it susceptible to damage. 【0066】 In this invention, a second welded portion 2212 is formed by welding the portion of the displacement region Z2 of the multiple tab pieces 221 that is away from the active material coated portion 21. Before welding the tab portion 22 to the electrode terminal 12, the second welded portion 2212 is partially cut or left uncut as needed. Since the second welded portion 2212 formed by welding the displacement region Z2 has a certain degree of rigidity compared to the multiple layers of bulging tab pieces 221, the second welded portion 2212 can support the welding press nozzle and improve the stability of the welding press nozzle, improve the welding quality between the tab portion 22 and the electrode terminal 12, widen the area of ​​the weldable region between the tab portion 22 and the electrode terminal 12, and ensure the rapid charging performance of the battery cell 10 while securing the current-carrying area. 【0067】 In the technical solution according to the embodiment of the present application, the area of ​​the welding region of the multiple tab pieces 221 can be increased by welding the overlapping region Z1 of the multiple tab pieces 221 to form a first welded portion 2211, and welding the portion of the displacement region Z2 of the multiple tab pieces 221 that is away from the active material coated portion 21 to form a second welded portion 2212. On the one hand, this is advantageous in increasing the utilization rate of the tab portion 22, improving the capacity of the battery cell 10, and suppressing temperature rise during overcurrent. On the other hand, when welding the tab portion 22 to the electrode terminal 12, the second welded portion 2212 can play a role in supporting the welding press nozzle more than the multiple bulging tab pieces, and there are no problems such as wrinkle formation, so the problem of welding defects caused by the welding press nozzle being pressed against the bulging region of the multiple tab pieces 221, as seen in the prior art, can be reduced. Furthermore, the cutting requirements of the tab portion 22 after welding can be relaxed, saving costs, while also improving the rapid charging performance of the battery cell 10. 【0068】 Further, by welding the deviation region Z2 to form the second welded portion 2212, it becomes possible to improve the efficiency of passing the tab portion 22 through the through-hole structure, thereby improving the assembly efficiency of the battery cell 10 and making the tab portion 22 less likely to be damaged by the hole wall of the through-hole structure. 【0069】 In some embodiments, the first welded portion 2211 is provided connected to the second welded portion 2212, that is, the boundary portions of the first welded portion 2211 and the second welded portion 2212 are welded to each other, so that the first welded portion 2211 and the second welded portion 2212 are integrally connected. 【0070】 In the above technical solution, for the plurality of bulged tab pieces 221, the first welded portion 2211 and the second welded portion 2212 provided connected to each other improve the rigidity of the plurality of tab pieces 221 after welding to a certain extent, so that the tab portion 22 is less likely to be damaged by the hole wall of the through-hole structure and improves the efficiency of passing the tab portion 22 through the through-hole structure. On the other hand, the second welded portion 2212 formed by welding is not easily crushed even when receiving pressure with respect to the first welded portion 2211, can reliably support the welding press nozzle, and has no problems such as wrinkling. Therefore, it is possible to reduce the problem that the welding press nozzle is pressed against the bulging regions of the plurality of tab pieces 221 and welding defects occur as seen in the prior art. 【0071】 Referring further to FIG. 5, along the width direction of the tab portion 22, the range of the ratio of the width size of the first welded portion 2211 to the width size of the second welded portion 2212 is 0.8 to 1.2. 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. Let the width size of the first welded portion 2211 be L1 and the width size of the second welded portion 2212 be L2. L1 and L2 may be equal, or L1 > L2, or L1 < L2. For example, L1 / L2 may be 0.8, 0.9, 1, 1.1, 1.2, etc. 【0072】 In the above technical solution, by limiting the range of the ratio of the width sizes of the first weld 2211 and the second weld 2212, the area of ​​the welding region of the multiple tab pieces 221 can be increased, and the utilization rate of the tab portion 22 can be increased, which is advantageous for improving the capacity of the battery cell 10 and suppressing the temperature rise during overcurrent. Furthermore, it is possible to reduce the problem of welding defects that occur when the welding press nozzle is pressed against the bulging regions of the multiple tab pieces 221, as seen in the prior art. 【0073】 In some embodiments, the ratio of the width size of the first welded portion 2211 to the width size of the tab portion 22 along the width direction of the tab portion 22 is in the range of 0.6 to 1. Specifically, let L1 be the width size of the first welded portion 2211 and L be the width size of the tab portion 22, for example, L1 / L may be 0.6, 0.7, 0.8, 0.9, 1, etc. In the above technical solution, by limiting the range of the ratio of the width sizes of the first welded portion 2211 to the width size of the tab portion 22, the area of ​​the welding region of the multiple tab pieces 221 can be widened, the utilization rate of the tab portion 22 can be increased, which is advantageous for improving the capacity of the battery cell 10 and suppressing temperature rise during overcurrent, and it is also possible to reduce the problem of welding defects that occur when the welding press nozzle is pressed against the bulging region of the multiple tab pieces 221, as seen in the prior art. 【0074】 Referring further to Figures 6 and 7, the ratio of the height sizes of the second weld 2212 and the first weld 2211 along the height direction of the tab portion 22 is 0.08 to 0.2. 【0075】 Specifically, the height direction of the tab portion 22 is parallel to the height direction of the active material coated portion 21, the height size of the first weld portion 2211 is h1, and the height size of the second weld portion 2212 is h2, for example, h2 / h1 may be 0.08, 0.1, 0.15, 0.2, etc. 【0076】 Due to the influence of manufacturing methods and tolerances, precise alignment is difficult after stacking and arranging multiple layers of tab pieces 221, resulting in a phenomenon where the edges are misaligned. Generally, the portion of the edge that is not aligned (misaligned) has a smaller height. Therefore, in this application, it is necessary to strictly control the height size of the misaligned region Z2 and the overlapping region Z1 formed by stacking multiple tab pieces 221. This makes it possible to satisfy the requirement of a certain range for the ratio of the height sizes of the second welded portion 2212 and the first welded portion 2211 formed by welding. 【0077】 In the above technical solution, by limiting the range of the height ratio between the first weld 2211 and the second weld 2212, the height of the first weld 2211 is made as large as possible, and the height of the second weld 2212 is made as small as possible. This improves the utilization rate of the tab portion 22 and reduces the cutting area of ​​the tab portion 22. This not only improves the stability of pressing the welding press nozzle against the tab portion 22 when welding the tab portion 22 to the pole terminal 12, but also makes it possible to increase the welding area between the tab portion 22 and the pole terminal 12, thereby improving the welding reliability between the tab portion 22 and the pole terminal 12. 【0078】 In some embodiments, the ratio of the height sizes of the first welded portion 2211 and the tab portion 22 along the height direction of the tab portion 22 is 0.45 to 0.65. Specifically, let h1 be the height size of the first welded portion 2211 and h be the height size of the tab portion 22, and for example, h1 / h may be 0.45, 0.5, 0.55, 0.6, 0.65, etc. 【0079】 In the above technical solution, by limiting the range of the height ratio between the first welded portion 2211 and the tab portion 22, the area of ​​the first welded portion 2211 can be increased, the utilization rate of the tab portion 22 can be increased, the cutting area of ​​the tab portion 22 can be reduced, which is advantageous in suppressing temperature rise during overcurrent, and the capacity of the battery cell 10 can be increased in order to improve the charge and discharge efficiency of the battery cell 10. 【0080】 Referring again to Figures 5 to 7, the height size of the second welded portion 2212 along the height direction of the tab portion 22 is 1 mm to 2 mm. For example, the height size h2 of the second welded portion 2212 may be 1 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, or 2 mm, etc. 【0081】 In the above technical solution, by limiting the height size of the second welded portion 2212 to satisfy the above conditions, on the one hand, the occupancy rate of the displacement region Z2 of the multiple tab pieces 221 is reduced as much as possible, the cutting area of ​​the tab portion 22 is narrowed, the yield rate of the electrode assembly 2 is improved, and the quality of the battery cell 10 is improved. On the other hand, by welding the displacement region Z2 assuming that positional displacement occurs in the multiple tab pieces 221, the area of ​​the welding region of the multiple tab pieces 221 is widened, and the problem of welding defects occurring when the welding press nozzle is pressed against the bulging region of the multiple tab pieces 221, as seen in the prior art, can be reduced. 【0082】 Referring again to Figure 7, due to the influence of the manufacturing method and manufacturing tolerances, multiple layers of tab pieces 221 are stacked to form an overlapping region Z1 and a misaligned region Z2. The overlapping region Z1 is welded to form a first welded portion 2211, and the misaligned region Z2 is welded to form a second welded portion 2212. The thickness of the second welded portion 2212 gradually decreases along the direction away from the first welded portion 2211, and it is possible to choose whether or not to cut this portion as needed. If cutting is necessary, the second welded portion 2212 can be cut more easily because its thickness gradually decreases. 【0083】 In some embodiments, the second welded portion 2212 has a first surface 2214 and a second surface 2215, the first surface 2214 and the second surface 2215 may be arranged opposite 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 arranged at an angle with respect to the height direction of the tab portion 22. 【0084】 For example, one surface of the first weld 2211 in the thickness direction may be flush with the first surface 2214 of the second weld 2212 in the thickness direction, and the second surface 2215 of the second weld 2212 in the thickness direction may be inclined with respect to one surface of the second weld 2212 in the thickness direction. As a result, the thickness of the second weld 2212 gradually decreases along the direction away from the first weld 2211. 【0085】 In another example, the first surface 2214 and the second surface 2215 in the thickness direction of the second weld 2212 can each be stretched in a direction toward each other along the direction away from the first weld 2211, so that the thickness of the second weld 2212 gradually decreases along the direction away from the first weld 2211. 【0086】 In the above technical solution, by forming the second welded portion 2212 in the aforementioned format, it is possible to easily determine whether or not cutting is necessary in subsequent processes, thereby improving the convenience of the cutting work. 【0087】 Referring again to Figure 7, the maximum distance s between the first surface 2214 and the second surface 2215 is 0.5 mm to 1 mm, meaning the maximum thickness of the second welded portion 2212 is 0.5 mm to 1 mm. For example, the maximum distance s between the first surface 2214 and the second surface 2215 is 0.5 mm, 0.6 mm, 0.8 mm, 1 mm, etc. In the above technical solution, by limiting the maximum distance between the first surface 2214 and the second surface 2215 to within the above range, on the one hand, it is possible to easily determine whether or not cutting is necessary in subsequent processes, thereby improving the convenience of cutting work, and on the other hand, it is possible to reduce the difficulty of welding, suppress welding defects, and improve welding quality. 【0088】 In some embodiments, the first surface 2214 extends along the height direction of the tab portion 22, and the second surface 2215 is provided at an inclination with respect to the height direction of the tab portion 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. That is, the first surface 2214 of the second weld portion 2212 formed by welding may be flush with the first weld portion 2211, and when welding the tab portion 22 and the electrode terminal 12, a large welding press nozzle can be used, and part of the welding press nozzle can be pressed against the first weld portion 2211 and the other part against the second weld portion 2212. That is, the first weld portion 2211 and the second weld portion 2212 can simultaneously support the welding press nozzle, reducing the difficulty of the welding work and reducing the problem of welding defects caused by the welding press nozzle being pressed against the bulging areas of multiple tab pieces, as seen in the prior art. Furthermore, by relaxing the cutting requirements for the tab portion after welding, costs can be saved while also improving the rapid charging performance of the battery cell 10. 【0089】 Therefore, in the above technical solution, by forming the second welded portion 2212 in the aforementioned form, on the one hand, it is possible to easily determine whether or not cutting is necessary in subsequent processes, thereby improving the convenience of cutting work, and on the other hand, it is possible to reduce the difficulty of welding, suppress welding defects, and improve welding quality. 【0090】 In some embodiments, the angle β between the first surface 2214 and the second surface 2215 is 10° to 45°. For example, the angle β between the first surface 2214 and the second surface 2215 may be 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, etc. By limiting the angle between the first surface 2214 and the second surface 2215 to the above range, the portion of the displacement region Z2 that is farther from the active material coated portion 21 can be easily welded with an ultrasonic stamp and an ultrasonic welding horn, thereby improving the convenience and quality of welding. 【0091】 Because the tab pieces are metal and made of a soft material, the first surface 2214 and the second surface 2215 are not necessarily perfectly flat. This is due to wrinkles that occur during the manufacturing and processing process. Therefore, the angles mentioned above are only approximate and do not affect the protection of other values ​​within the error range. 【0092】 Referring to Figures 8 to 11, Figure 8 is a schematic diagram of the structure of the electrode assembly 2 according to some embodiments of the present application before the tab portion 22 is paired, and Figure 9 is a schematic diagram of the structure of the first ultrasonic welding anvil 81 and the first ultrasonic welding horn 82 after the tab portion 22 of the electrode assembly 2 according to some embodiments of the present application has been paired. Figure 10 is a schematic diagram of the structure of the first ultrasonic welding anvil 81 and the first ultrasonic welding horn 82 before the overlapping region Z1 of the tab portion 22 of the electrode assembly 2 according to some embodiments of the present application is welded. Figure 11 is a schematic diagram of the structure of the electrode assembly 2 according to some embodiments of the present application, in which the overlapping region Z1 of the tab portion 22 is welded ultrasonically to form the first welded portion 2211. The first welded portion 2211 is formed by ultrasonic welding. 【0093】 Specifically, after pairing multiple tab pieces 221, the multiple tab pieces 221 are stacked and arranged. The stacked multiple tab pieces 221 have an overlapping region Z1 and a misaligned region Z2. The overlapping region Z1 is sandwiched between the first ultrasonic welding anvil 81 and the first ultrasonic welding horn 82, and any two adjacent tab pieces 221 melt due to friction, thereby welding the overlapping region Z1 of the multiple tab pieces 221 together to form a first welded portion 2211. 【0094】 In the above technical solution, since the first welded portion 2211 is formed by ultrasonic welding, the welding speed and welding efficiency are improved, and the surface quality of the overlapping region Z1 after welding is improved. Furthermore, the welding process is clean, stable, and highly reliable, and energy consumption is reduced. 【0095】 Referring to Figures 12 to 14, Figure 12 is a schematic diagram of the structure of the second ultrasonic welding anvil 91 and the second ultrasonic welding horn 92 before the displacement region Z2 of the tab portion 22 of the electrode assembly 2 according to some embodiments of the present application is welded. Figure 13 is a schematic diagram of the structure of the electrode assembly 2 according to some embodiments of the present application, in which the displacement region Z2 of the tab portion 22 away from the active material coated portion 21 is welded ultrasonically to form the second welded portion 2212, and Figure 14 is a schematic diagram of the structure of the electrode assembly 2 according to some embodiments of the present application. The second welded portion 2212 is formed by ultrasonic welding. 【0096】 Specifically, the portion of the displacement region Z2 away from the active material coated portion 21 is sandwiched between the second ultrasonic welding anvil 91 and the second ultrasonic welding horn 92, and any two adjacent tab pieces 221 melt due to friction, thereby welding together the portions of the displacement region Z2 of multiple tab pieces 221 away from the active material coated portion 21 to form a second welded portion 2212. 【0097】 In the above technical solution, since the second weld 2212 is formed by ultrasonic welding, the welding speed and welding efficiency are improved, and the surface quality of the overlapping region Z1 after welding is improved. Furthermore, the welding process is clean, stable, and highly reliable, and energy consumption is reduced. 【0098】 In some other embodiments, the displacement region Z2 obtained by stacking multiple tab pieces 221 includes an end displacement region Z21, which is located at one end of the overlapping region Z1 away from the active material coated portion 21. The first portion of the end displacement region Z21 is bent toward the second portion which is the remainder of the end displacement region Z21, in a direction toward the active material coated portion 21, and then both portions are joined together by welding in an overlapping state to form a second welded portion 2212. 【0099】 Specifically, the misaligned edge region Z21 of the stacked multiple layers of tab pieces 221 adversely affects the subsequent assembly of the tab portion 22 and the laser welding of the tab portion 22 to the electrode terminal 12. Therefore, in the conventional technology, during the manufacturing process of the electrode assembly 2, it is necessary to cut off all of the misaligned edge region Z21 of the multiple layers of tab pieces 221 with a cutting blade, leaving only the overlapping region Z1 of the multiple layers of tab pieces 221 without misalignment. Then, the multiple layers of tab pieces 221 in the remaining overlapping region Z1 after cutting are formed as a tab portion 22 by ultrasonic pre-welding, and then the tab portion 22 to the electrode terminal 12 is laser-welded. However, during the process of cutting the tab pieces 221, it is necessary to adjust the position of the cutting blade in real time to improve the cutting quality. Also, if the relative positions of the tab portions 22 differ on electrode assemblies 2 with different specifications, it is necessary to adjust the position of the cutting blade in order to cut multiple tab portions 22 simultaneously on electrode assemblies 2 with different specifications. Therefore, the processing efficiency is low, and since the overall length of the cut tab portion 22 is shortened, the area of ​​the welded joint with the electrode terminal 12 becomes smaller, reducing the current-conducting performance and affecting the charge and discharge efficiency of the battery cell 10. In addition, there is the problem of wasting material from the tab piece 221. 【0100】 In the embodiment of the present invention, the misaligned end regions Z21 of multiple layers of tab pieces 221 are folded, laminated, and connected, thereby enabling the reuse of the misaligned end regions Z21. This improves the adverse effects of the misaligned end regions Z21 of multiple layers of tab pieces 221 on subsequent assembly of the tab portion 22 (for example, when the tab portion 22 passes through the through hole of the electrode terminal 12) and subsequent welding between the tab portion 22 and the electrode terminal 12 or transfer plate. Furthermore, compared to the case where the entire misaligned end region Z21 is cut off, the area of ​​pre-welding of the tab portion 22 by ultrasonic waves can be increased, thereby widening the electrical connection area between the tab portion 22 and the electrode terminal 12, which is advantageous in improving current conduction performance and increasing the charge and discharge efficiency of the battery cell 10. Moreover, since it is not necessary to cut off the misaligned end region Z21 of the tab portion 22 with a cutting blade, the time required to adjust the cutting blade in the cutting process can be eliminated. Furthermore, since there is no need to introduce a process to adjust the cutting blade in order to cut multiple tab portions 22 of the electrode assembly 2 simultaneously, it is advantageous in shortening the cycle time required for manufacturing the electrode assembly 2 and improving the manufacturing efficiency of the electrode assembly 2. In addition, by reusing the offset region Z21 at the ends of the multiple layers of tab pieces 221, material waste can be reduced and the material utilization rate of the tab portion 22 can be improved. 【0101】 Referring to Figures 15 and 16, Figure 15 is a local enlarged view of an electrode assembly 2 according to some other embodiments of the present application, and Figure 16 is a plan view of an electrode assembly 2 according to some other embodiments of the present application. In some further embodiments, the displacement region Z2 is located on at least one side of the overlapping region Z1 and is welded to form a third weld 2213. Specifically, the displacement region Z2 after stacking a plurality of tab pieces 221 includes two lateral displacement regions Z22, the two lateral displacement regions Z22 are located on both sides in the width direction of the overlapping region Z1, and at least one lateral displacement region Z22 is welded to form a third weld 2213. 【0102】 In the above technical solution, the displacement region Z2 is located on at least one of the two sides of the overlapping region Z1 and is welded to form a third welded portion 2213. On the one hand, this increases the area of ​​the welded region of the multiple tab pieces 221 and improves the utilization rate of the tab portion 22, which is advantageous for improving the capacity of the battery cell 10 and suppressing temperature rise during overcurrent. On the other hand, it reduces the problem of welding defects caused by the welding press nozzle being pressed against the bulging regions of the multiple tab pieces 221, as seen in the prior art, and makes it easier for the tab portion 22 to pass through the through hole in the electrode terminal 12. 【0103】 Referring to Figure 17, which is a schematic cross-sectional view of the tab portion 22 of the electrode assembly 2 according to yet another embodiment of the present application. In some further embodiments, a first portion of at least one lateral displacement region Z22 is bent toward the second portion which is the remainder of the lateral displacement region Z22, in a direction toward the active material coated portion 21, and then both portions are joined together by welding in an overlapping state to form a third welded portion 2213. 【0104】 Specifically, the lateral misalignment region Z22 of the stacked multiple layers of tab pieces 221 adversely affects the subsequent assembly of the tab portion 22 and the laser welding of the tab portion 22 to the electrode terminal 12. Therefore, in the conventional technology, during the manufacturing process of the electrode assembly 2, it is necessary to cut off all of the lateral misalignment region Z22 of the multiple layers of tab pieces 221 with a cutting blade, leaving only the overlapping region Z1 of the multiple layers of tab pieces 221 without misalignment. Then, the multiple layers of tab pieces 221 in the remaining overlapping region Z1 after cutting are formed as a tab portion 22 by ultrasonic pre-welding, and then the tab portion 22 to the electrode terminal 12 is laser-welded. However, during the process of cutting the tab pieces 221, it is necessary to adjust the position of the cutting blade in real time in order to improve the cutting quality. Also, if the relative positions of the tab portions 22 differ on electrode assemblies 2 of different specifications, it is necessary to adjust the position of the cutting blade in order to cut multiple tab portions 22 simultaneously on electrode assemblies 2 of different specifications. Therefore, the processing efficiency is low, and since the overall length of the tab portion 22 after cutting is shortened, the area of ​​the weld marks where it is welded to the electrode terminal 12 becomes smaller, which reduces the current-conducting performance and affects the charge and discharge efficiency of the battery cell 10. In addition, there is the problem of wasting material from the tab piece 221. 【0105】 In the embodiment of the present invention, the lateral misalignment regions Z22 of multiple layers of tab pieces 221 are folded, laminated, and connected, thereby enabling the reuse of the lateral misalignment regions Z22. This improves the adverse effects of the lateral misalignment regions Z22 of multiple layers of tab pieces 221 on subsequent assembly of the tab portion 22 (for example, when the tab portion 22 passes through the through hole of the electrode terminal 12) and on subsequent welding between the tab portion 22 and the electrode terminal 12 or transfer plate. Furthermore, compared to the case where the entire lateral misalignment region Z22 is cut off, the area of ​​pre-welding of the tab portion 22 by ultrasonic waves can be increased, thereby widening the electrical connection area between the tab portion 22 and the electrode terminal 12, which is advantageous in improving current conduction performance and increasing the charge and discharge efficiency of the battery cell 10. Moreover, since it is not necessary to cut off the lateral misalignment regions Z22 of the tab portion 22 with a cutting blade, the time required to adjust the cutting blade in the cutting process can be eliminated. Furthermore, since there is no need to introduce a process to adjust the cutting blade in order to cut multiple tab portions 22 of the electrode assembly 2 simultaneously, it is advantageous in shortening the cycle time required for manufacturing the electrode assembly 2 and improving the manufacturing efficiency of the electrode assembly 2. In addition, by reusing the lateral displacement region Z22 of the multiple layers of tab pieces 221, material waste can be reduced and the material utilization rate of the tab portion 22 can be improved. 【0106】 In short, by folding and stacking the misaligned regions Z2 of the multiple layers of tab pieces 221 to enable reuse, the adverse effects of the misaligned regions Z2 of the multiple layers of tab pieces 221 on subsequent processes are eliminated, and the electrical connection area between the tab portion 22 and the electrode terminal 12 is widened, improving current conduction performance. Furthermore, since the process and time required to adjust the position of the cutting blade in real time can be eliminated, the processing efficiency of the electrode assembly 2 is improved, which is advantageous in meeting the cycle time requirements of a high-speed mass production line, and is also advantageous in reducing material waste and increasing the material utilization rate of the tab pieces 221. 【0107】 Referring again to Figures 3 and 4, according to some embodiments of the present application, the present 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 electrode terminals 12, the electrode assembly 2 is provided inside the housing 11, the tab portion 22 is connected to the electrode terminals 12, and the electrode assembly 2 is one of the above embodiments. 【0108】 According to the technical solution of the embodiment of the present invention, by applying the electrode assembly 2, on the one hand, it is advantageous to increase the utilization rate of the tab portion 22, improve the capacity of the battery cell 10, and suppress the temperature rise during overcurrent. On the other hand, when welding the tab portion 22 and the electrode terminal 12, the second weld portion 2212 can play a role in supporting the welding press nozzle more than the multiple bulging tab pieces, and there are no problems such as wrinkle formation, so the problem of welding defects caused by the welding press nozzle being pressed against the bulging areas of the multiple tab pieces 221, as seen in the prior art, can be reduced, improving the reliability of use of the battery cell 10, relaxing the cutting requirements of the tab portion 22 after welding, reducing the difficulty of manufacturing the battery cell 10, saving costs, and improving the rapid charging performance of the battery cell 10. 【0109】 Referring to Figures 12 and 13, Figure 12 is a schematic local cross-sectional view of a battery cell 10 according to some embodiments of the present application. Figure 13 is a schematic local cross-sectional view of a battery cell 10 according to some embodiments of the present application. A housing portion 121 is provided in the electrode terminal 12, and at least a part of the tab portion 22 is inserted into and housed in the housing portion 121, and the tab portion 22 is electrically connected to the electrode terminal 12. That is, the electrode terminal 12 is configured as a hollow structure. 【0110】 Here, "at least a part" means that the tab portion 22 may be entirely housed within the housing portion 121, or a portion of the tab portion 22 may be housed within the housing portion 121. By providing the housing portion 121 on the electrode terminal 12, the hollow structure of the housing portion 121 can reduce the weight of the electrode terminal 12 to some extent, improving the weight-energy density of the battery cell 10 and the battery 100. At the same time, since the tab portion 22 can be housed within the housing portion 121, the assembly efficiency of the tab portion 22 is improved, the space occupied by the tab portion 22 is reduced, and the internal space of the battery cell 10 can be fully utilized. As a result, the fitting between the holder 3 and the electrode terminal 12 and the fitting between the holder 3 and the tab portion 22 are both tighter and more reliable, making the structure of the battery cell 10 more compact and further advantageous in improving the energy density of the battery cell 10. 【0111】 More specifically, by housing part or all of the tab portion 22 within the housing portion 121, the portion of the tab portion 22 located within the housing portion 121 utilizes the space inside the electrode terminal 12, thereby reducing the space occupied by the tab portion 22 within the housing 11. Even if the size of the housing 11 is fixed, extra space can be secured inside the housing 11, allowing for the accommodation of a larger active material coated portion 21 and improving the volumetric energy density of the battery cell 10. For example, if the tab portion 22 is drawn out from the side of the active material coated portion 21 closer to the electrode terminal 12, the space occupied by the tab portion 22 between the active material coated portion 21 and the electrode terminal 12 can be saved. As a result, the dimensions of the active material coated portion 21 can be increased along the direction in which the tab portion 22 is drawn out, reducing the distance between the active material coated portion 21 and the electrode terminal 12, thereby improving the energy density of the battery cell 10. 【0112】 Furthermore, by housing at least a portion of the tab portion 22 within the housing portion 121, the space occupied by the battery cell 10 itself can be reduced. This allows more battery cells 10 to be housed in a battery 100 of the same volume, thereby improving the volumetric energy density of the battery 100. Additionally, by housing at least a portion of the tab portion 22 within the housing portion 121 and utilizing the space inside the electrode terminal 12, the redundancy of the tab portion 22 within the housing 11 can be reduced to some extent, reducing the short-circuit rate between the tab portion 22 and the active material coating portion 21, and thus reducing the short-circuit rate of the battery cell 10. As a result, the reliability and stability of the operation of the battery cell 10 and the battery 100 can be improved. 【0113】 In the embodiment of the present invention, the housing portion 121 may be positioned on the side of the electrode terminal 12 facing the active material coated portion 21, or it may be positioned on the side of the electrode terminal 12 away from the active material coated portion 21. 【0114】 For illustrative purposes, referring again to Figures 12 and 13, when the housing portion 121 is located on the side of the electrode terminal 12 facing the active material coated portion 21, the housing portion 121 includes a first housing groove 12110. The surface of the electrode terminal 12 facing the active material coated portion 21 is the inner end face 122 of the electrode terminal, and the groove opening of the first housing groove 12110 is formed on the inner end face 122 of the electrode terminal. At least a portion of the tab portion 22 is housed within the first housing groove 12110. 【0115】 For example, the first housing groove 12110 is a groove body, and the groove body is a groove-like structure having a certain depth. For example, if the pole terminal 12 is provided on the upper end wall of the housing 11 and the inner end face 122 of the pole terminal is the lower surface of the pole terminal 12, the first housing groove 12110 is formed as a housing groove with a groove opening that opens downwards and a groove wall that is recessed upwards. Alternatively, for example, if the pole terminal 12 is provided on the lower end wall of the housing 11 and the inner end face 122 of the pole terminal is the upper surface of the pole terminal 12, the first housing groove 12110 is formed as a housing groove with a groove opening that opens upwards and a groove wall that is recessed downwards. 【0116】 In the above technical solution, on the one hand, by creating a first housing groove 12110 in the electrode terminal 12, the weight of the electrode terminal 12 can be reduced to some extent, thereby improving the gravimetric energy density of the battery cell 10 and the battery 100. On the other hand, since the groove opening of the first housing groove 12110 is formed on the inner end face 122 of the electrode terminal, which is the surface of the electrode terminal 12 closer to the active material coated portion 21, the first housing groove 12110 opens toward the active material coated portion 21, and the tab portion 22 can be easily inserted into the first housing groove 12110, thereby improving assembly efficiency. Furthermore, this type of first housing groove 12110 is easy to process, improving manufacturing efficiency. 【0117】 Furthermore, because the first housing groove 12110 is easy to process and has a large volume, it can accommodate more tab portions 22. Also, since the first housing groove 12110 opens toward the active material coating portion 21, it functions as a buffer and temporary storage area for the electrolyte, allowing more electrolyte to be stored in the housing 11. Since the electrolyte is consumed during charging and discharging of the battery cell 10, a larger amount of electrolyte can extend the service life of the cell. Moreover, because the first housing groove 12110 opens toward the active material coating portion 21, it also functions as a buffer and storage area for gas generated inside the electrode assembly 2, suppressing the expansion of the battery cell 10 and improving the reliability and stability of the battery cell 10. 【0118】 Furthermore, since the first housing groove 12110 is located inside the electrode terminal 12, foreign matter and impurities from the outside are less likely to enter the first housing groove 12110, thereby reducing the influence of external foreign matter and impurities on the electrode assembly 2. This improves the stability and reliability of the electrode assembly 2 when it is in operation, and consequently, the stability and reliability of the battery cell 10 and the battery 100 can also be improved. 【0119】 Referring again to Figure 12, in the embodiment of the present application, there are no restrictions on the method of connecting the pole terminal 12 and the housing 11; for example, welding or riveting may be used. For example, if the two are joined by riveting, a mounting hole 113 is provided in the housing 11, and the pole terminal 12 is attached to the mounting hole 113 by riveting. Of course, even if the two are joined by welding or other methods, a mounting hole 113 may also be provided in the housing 11, and it is understood that this would make it easier to attach the pole terminal 12 to the housing 11 via the mounting hole 113, but this specification does not limit this. 【0120】 Furthermore, the first accommodating groove 12110 can be provided corresponding to the position of the mounting hole 113. In other words, by configuring the orthographic projection of the first accommodating groove 12110 to be located within the orthographic projection range of the mounting hole 113 on the projection plane perpendicular to the axial R of the pole terminal 12, the depth of the first accommodating groove 12110 can be increased, allowing for the accommodation of more tab portions 22, and as a result, the space occupied by the tab portions 22 within the housing 11 can be further reduced. Specifically, when a mounting hole 113 is provided in the housing 11 and the pole terminal 12 is mounted in the mounting hole 113, the depth H1 of the first accommodating groove 12110 is greater than or equal to the minimum distance H2 from the inner end face 122 of the pole terminal to the mounting hole 113 along the axial R of the pole terminal 12. 【0121】 The specific shape of the first housing groove 12110 is not limited and may be regular or irregular. For example, it may be a columnar groove with a rectangular, elliptical, or runout 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. Therefore, the depth H1 of the first housing groove 12110 refers to the maximum depth that the first housing groove 12110 has along the axial radius R of the pole terminal 12. 【0122】 Along the axial radius R of the electrode terminal 12, the depth H1 of the first housing groove 12110 is set to be greater than or equal to the minimum distance H2 from the inner end face 122 of the electrode terminal to the mounting hole 113. This is advantageous because it allows for full utilization of the volume of the electrode terminal 12 to secure a large depth in the first housing groove 12110, thereby accommodating more tab portions 22. This further reduces the space occupied by the tab portions 22 within the housing 11, further improving the volumetric energy density of the battery cell 10, and reducing the redundancy of the tab portions 22 within the housing 11. In addition, the large depth of the first housing groove 12110 allows for the storage of gas generated in the electrode assembly 2, improving the reliability and stability of the battery cell 10, and also allows for the storage of more electrolyte, extending the service life of the battery cell 10. 【0123】 Referring again to Figures 12 and 13, in order to improve the stability and reliability of the electrical connection between the active material coated portion 21 and the electrode terminal 12, in some embodiments of the present application, the electrical connection position between the tab portion 22 and the electrode terminal 12 can be provided on the groove wall of the first housing groove 12110 formed in the housing portion 121. 【0124】 For example, the tab portion 22 can be electrically connected to the electrode terminal 12 by welding, and the electrical connection location is the welding point between the tab portion 22 and the electrode terminal 12. At the same time, the welding method between the tab portion 22 and the electrode terminal 12 is not limited; for example, laser welding can be used, and depending on factors such as the position, angle, and structure of the welding area, vertical welding, inclined welding, lap joint welding, or seal welding can be selected. In other embodiments of the present invention, the electrical connection between the tab portion 22 and the electrode terminal 12 can be achieved by methods other than welding, such as using conductive adhesive or conductive pins. To simplify the explanation, the following description will use as an example the case in which the tab portion 22 is welded to the electrode terminal 12 to form an electrical connection, and the welding location is the electrical connection location between the tab portion 22 and the electrode terminal 12. 【0125】 Specifically, the electrode terminal 12 includes a first end wall 12111 and a first side wall 12113, with the first end wall 12111 located on the side of the first side wall 12113 away from the active material coated portion 21. The first end wall 12111 and the first side wall 12113 surround each other to form the first housing groove 12110, and the electrical connection position between the tab portion 22 and the electrode terminal 12 is located on the first end wall 12111 and / or the first side wall 12113. In other words, the tab portion 22 only needs to be welded to at least one of the first end wall 12111 and the first side wall 12113. 【0126】 In the above technical solution, by providing the electrical connection position between the tab portion 22 and the electrode terminal 12 on at least one of the first end wall 12111 and the first side wall 12113, the first housing groove 12110 not only serves to accommodate at least a part of the tab portion 22, but the groove wall of the first housing groove 12110 also serves to realize an electrical connection with the tab portion 22. This simplifies the structure of the electrode terminal 12, making it easier to process, and simplifies the structure of the tab portion 22, reducing the redundant parts of the tab portion 22 and lowering the cost of the tab portion 22. Furthermore, by realizing an electrical connection with the tab portion 22 using the groove wall of the first housing groove 12110, a relatively large electrical connection area between the tab portion 22 and the electrode terminal 12 can be secured, reducing the difficulty of electrical connection, improving the reliability and stability of the electrical connection, and further improving the performance of the battery cell 10. 【0127】 Furthermore, since the electrical connection position between the tab portion 22 and the pole terminal 12 is located within the first housing groove 12110, it is possible to prevent the electrical connection position from protruding outside the pole terminal 12 and occupying the external space of the pole terminal 12. In addition, since the electrical connection position is protected by the pole terminal 12, it is possible to improve the reliability and stability of the electrical connection between the tab portion 22 and the pole terminal 12. 【0128】 Furthermore, in the embodiment of the present application, since the first end wall 12111 is configured as a closed structure without a through hole 12130, the first housing groove 12110 is isolated from the external space of the housing 11, and the problem of electrolyte leakage from the housing 11 through the first housing groove 12110 can be reduced. 【0129】 Referring again to Figures 12 and 13, in several selectable embodiments, the local shape of the tab portion 22 is matched to the local shape of the first end wall 12111, and the two are bonded together to achieve electrical connection, so that the electrical connection position between the tab portion 22 and the first end wall 12111 extends along the length or width direction of the first end wall 12111. For example, if the first end wall 12111 is flat, the local shape of the tab portion 22 may also be flat and bonded to the first end wall 12111, and the bonded portion can be electrically connected by welding or the like. This increases the area of ​​electrical connection and improves the reliability and stability of the electrical connection. 【0130】 Furthermore, when the electrical connection between the tab portion 22 and the first end wall 12111 is made by welding, the first end wall 12111 is located on the side of the first housing groove 12110 away from the active material coated portion 21, which facilitates the welding process. For example, welding can be performed from the side of the electrode terminal 12 away from the active material coated portion 21. 【0131】 The shape of the first end wall 12111 is not limited and can be, for example, a flat plate or an arc-shaped plate. When the first end wall 12111 has a flat plate structure, it is positioned at a predetermined angle with respect to the axial radius R of the pole terminal 12. For example, it can be a flat plate structure perpendicular to the axial radius R of the pole terminal 12, or it can be an inclined plate structure that is not perpendicular to the axial radius R of the pole terminal 12; there are no restrictions on the direction of inclination. 【0132】 Of course, in other embodiments of the present invention, the electrical connection points between the tab portion 22 and the first end wall 12111 do not necessarily extend along the length or width of the first end wall 12111, and it is possible to provide multiple scattered locations, for example. For example, the tab portion 22 may have multiple parts arranged at intervals, each welded to the first end wall 12111, but details are omitted here. 【0133】 Referring to Figure 14, which is a schematic local cross-sectional view of a battery cell 10 according to several embodiments of the present application. When the tab portion 22 is electrically connected to the first end wall 12111, a first recessed groove 12112 can be provided on the first end wall 12111, and the recessing direction of the first recessed groove 12112 is in a direction away from the active material coated portion 21. At least a portion of the electrical connection position between the tab portion 22 and the first end wall 12111 is located within the first recessed groove 12112. Exemplarily, at least a portion of the tab portion 22 can be provided within the first recessed groove 12112 and connected to a portion of the first end wall 12111 that defines the first recessed groove 12112. In the above technical solution, on the one hand, the electrical connection position of the tab portion 22 can be pre-positioned and position-constrained using the first recessed groove 12112. This is advantageous not only for accurately identifying the connection position and making electrical connections, thereby improving manufacturing efficiency, but also for enhancing the stability and reliability of the tab portion 22, and consequently for improving the stability and reliability of the battery cell 10 during the charging and discharging process. On the other hand, by providing the first recessed groove 12112 on the first end wall 12111, the local thickness of the first end wall 12111 can be locally reduced. This is advantageous not only for welding work, but also for reducing the weight of the electrode terminal 12 and improving the gravimetric energy density of the battery cell 10. 【0134】 Referring again to Figures 13 and 14, in the embodiment of the present invention, the pole terminal 12 may be provided with a first groove 126 as needed. The first groove 126 is located on the side of the pole terminal 12 away from the active material coated portion 21, that is, the surface of the pole terminal 12 on the side away from the active material coated portion 21 is the outer end surface 123 of the pole terminal, and the groove opening of the first groove 126 is formed on the outer end surface 123 of the pole terminal. 【0135】 The first groove 126 is understood to be a groove body, and the groove body is understood to be a groove-like structure having a certain depth. Furthermore, when the electrode terminal 12 is provided on the upper end wall of the housing 11 and the outer end face 123 of the electrode terminal is the upper surface of the electrode terminal 12, the first groove 126 is formed as a structure in which the groove opening is upward and the groove wall is recessed downward (i.e., recessed in the direction toward the electrode assembly 2). Also, for example, when the electrode terminal 12 is provided on the lower end wall of the housing 11 and the outer end face 123 of the electrode terminal is the lower surface of the electrode terminal 12, the first groove 126 is formed as a structure in which the groove opening is downward and the groove wall is recessed upward (i.e., recessed in the direction toward the direction toward the electrode assembly 2). 【0136】 In the above technical solution, on the one hand, by providing the first groove 126 on the electrode terminal 12, the weight of the electrode terminal 12 can be further reduced, and the gravimetric energy density of the battery cell 10 and the battery 100 can be improved. On the other hand, the first groove 126 is located on the outside of the electrode terminal 12, that is, it opens on the side away from the inside of the housing 11 of the electrode terminal 12, and structural members that electrically connect each battery cell 10 in the battery 100 can be housed or attached to the first groove 126. This makes full use of the space inside the electrode terminal 12, and the space utilization rate and volumetric energy density of the battery 100 can be increased. 【0137】 Furthermore, the electrode terminal 12 is provided with a first housing groove 12110 and a first recessed groove 126. The first recessed groove 126 is located on the side of the first housing groove 12110 away from the active material coated portion 21 and opens in a direction away from the first housing groove 12110. Therefore, it is advantageous to laser weld the tab portion 22 and the first end wall 12111 via the first recessed groove 126 from the outside of the electrode terminal 12, i.e., the side of the electrode terminal 12 away from the active material coated portion 21, making it easy to achieve electrical connection between the tab portion 22 and the electrode terminal 12 by welding from the outside. In other words, the above structure makes it easier to weld the electrode terminal 12 and the tab portion 22 from the outside via the first recessed groove 126, simplifying the processing and manufacturing of the battery cell 10 and saving processing and manufacturing costs. 【0138】 Furthermore, in order to easily and effectively weld the tab portion 22 and the groove wall of the first housing groove 12110 via the first recessed groove 126 and improve the reliability of the welding between the tab portion 22 and the groove wall of the first housing groove 12110, in the embodiment of the present application, the portion located between the first recessed groove 126 and the first housing groove 12110 is laser-welded to the tab portion 22, that is, the gap portion 127 shown in Figure 14 is laser-welded to the tab portion 22, thereby enabling electrical connection between the electrode assembly 2 and the electrode terminal 12. The gap portion 127 located between the first recessed groove 126 and the first housing groove 12110 of the electrode terminal 12 is relatively thin, and the gap portion 127 separates the first recessed groove 126 and the first housing groove 12110. The side wall of the spacing portion 127 closest to the active material coated portion 21 may function as the first end wall 12111. When welding the tab portion 22 to the first end wall 12111, the relatively thin thickness of the spacing portion 127 is advantageous for welding the tab portion 22 to the first end wall 12111 via the first groove 126, thereby improving the convenience and reliability of welding. 【0139】 Referring again to Figure 13, the battery cell 10 may also include a groove cover 7. The groove cover 7 is provided on the electrode terminal 12 and covers the groove opening of the first recessed groove 126. In the above technical solution, by providing a groove cover 7 that covers the first recessed groove 126, the electrode terminal 12 can be indirectly electrically connected to the bus member via the groove cover 7. Furthermore, by appropriately designing the position and structure of the groove cover 7, the electrical connection between the groove cover 7 and the bus member becomes easier, and the connection area can be increased. In this way, by providing the groove cover 7, the electrical connection between adjacent battery cells 10 in the battery 100 becomes easier. Also, since the electrical connection positions between the battery cells 10 are located on the groove cover 7 and are isolated by the first recessed groove 126 from the electrical connection positions between the tab portion 22 and the electrode terminal 12, interference between the two is suppressed, and the stability and reliability of the battery cell 10 can be further improved. 【0140】 For illustrative purposes, referring to Figure 15, which is a schematic local cross-sectional view of a battery cell 10 according to some embodiments of the present application. The housing portion 121 may also be configured to include a second housing groove 12120. The surface of the electrode terminal 12 away from the active material coated portion 21 is the electrode terminal outer end face 123, and the groove opening of the second housing groove 12120 is formed on the electrode terminal outer end face 123. Furthermore, the second housing groove 12120 communicates with the interior of the housing 11 via a through hole 12130, and the tab portion 22 is positioned with a through hole 12130 and at least a portion of it is housed within the second housing groove 12120. 【0141】 The second housing groove 12120 is understood to be a groove body, and the groove body is understood to be a groove-like structure having a certain depth. For example, if the pole terminal 12 is provided on the upper end wall of the housing 11 and the outer end face 123 of the pole terminal is the upper surface of the pole terminal 12, the second housing groove 12120 is formed as a housing groove with a groove opening that opens upward and a groove wall that is recessed downward. Alternatively, if the pole terminal 12 is provided on the lower end wall of the housing 11 and the outer end face 123 of the pole terminal is the lower surface of the pole terminal 12, the second housing groove 12120 is formed as a housing groove with a groove opening that opens downward and a groove wall that is recessed upward. 【0142】 Referring again to Figure 15 in the above technical solution, on the one hand, by providing the second housing groove 12120 on the electrode terminal 12, the weight of the electrode terminal 12 can be reduced to some extent, thereby improving the gravimetric energy density of the battery cell 10 and the battery 100. On the other hand, the groove opening of the second housing groove 12120 is formed on the outer end surface 123 of the electrode terminal, and the outer end surface 123 is the surface of the electrode terminal 12 that is away from the active material coating portion 21, so the second housing groove 12120 opens in a direction away from the active material coating portion 21. As a result, when at least a part of the tab portion 22 is housed in the second housing groove 12120, it becomes easier to organize and store the tab portion 22 through the groove opening of the second housing groove 12120, and electrical connection operations between the tab portion 22 and the electrode terminal 12 can be easily performed through the groove opening of the second housing groove 12120, thereby reducing the difficulty of manufacturing the battery cell 10 and improving the manufacturing efficiency of the battery cell 10. 【0143】 Furthermore, since the second housing groove 12120 communicates with the inside of the housing 11 via the through hole 12130, the second housing groove 12120 can be used as a buffer and temporary storage structure for the electrolyte, allowing more electrolyte to be stored in the housing 11. Since the battery cell 10 consumes electrolyte during the charging and discharging process, increasing the amount of electrolyte can extend the service life of the battery cell 10. Moreover, since the second housing groove 12120 can also communicate with the inside of the housing 11 via the through hole 12130, it also functions as a gas containment and buffer structure for gases generated inside the electrode assembly 2, suppressing the expansion of the battery cell 10 and improving the reliability and stability of the battery cell 10. 【0144】 Furthermore, if the housing portion 121 has a second housing groove 12120, and the tab portion 22 has a through hole 12130 and at least a portion of it is housed in the second housing groove 12120, the electrical connection position between the tab portion 22 and the pole terminal 12 is not particularly limited. For example, if the tab portion 22 has a through hole 12130 and at least a portion of it is housed in the second housing groove 12120, in this embodiment of the present application, the electrical connection position between the tab portion 22 and the pole terminal 12 is located at the hole wall of the through hole 12130 formed in the pole terminal 12. 【0145】 In the above technical solution, by providing the electrical connection position between the tab portion 22 and the electrode terminal 12 on the wall of the through hole 12130, the electrical connection operation between the tab portion 22 and the electrode terminal 12 via the second housing groove 12120 becomes easier. Furthermore, when the electrical connection area between the tab portion 22 and the electrode terminal 12 is large, the through hole 12130 can be sealed by the electrical connection between the tab portion 22 and the electrode terminal 12, thereby reducing sealing costs, suppressing electrolyte leakage, and even eliminating the need for sealing materials. 【0146】 Specifically, by welding the tab portion 22 to the wall of the through-hole 12130 at a position communicating with the second housing groove 12120 of the through-hole 12130, operability can be improved. Furthermore, by controlling the weld marks, the through-hole 12130 can be sealed by the weld marks and the tab portion 22, thereby improving the problem of electrolyte leakage from the through-hole 12130 within the housing 11. 【0147】 Furthermore, as an example, if the tab portion 22 has a through hole 12130 and at least a portion of it is housed in the second housing groove 12120, in some other embodiments of the present application, the electrical connection position between the tab portion 22 and the pole terminal 12 can be located at the groove wall of the second housing groove 12120 formed in the pole terminal 12. This facilitates the electrical connection operation, and for example, when welding the tab portion 22 to the groove wall of the second housing groove 12120 formed in the pole terminal 12, it is possible to prevent conductive fine particles generated during welding from entering the housing 11 and causing problems such as short circuits. 【0148】 Referring again to Figure 15, the electrode terminal 12 includes a second end wall 12121 and a second side wall 12123, with the second end wall 12121 located on the side of the second side wall 12123 closer to the active material coated portion 21. The second end wall 12121 and the second side wall 12123 surround each other to form a second housing groove 12120, and a through hole 12130 is provided in the second end wall 12121. The electrical connection position between the tab portion 22 and the electrode terminal 12 is located in the second end wall 12121 and / or the second side wall 12123. More specifically, the tab portion 22 and the electrode terminal 12 can be electrically connected by welding, and therefore the welding position becomes the electrical connection position between the tab portion 22 and the electrode terminal 12. In other embodiments of the present invention, the electrical connection between the tab portion 22 and the electrode terminal 12 can be achieved by other methods instead of welding, such as by providing a conductive adhesive or conductive pins. Details will be omitted here. 【0149】 To simplify the explanation, the following description will use as an example the case in which the tab portion 22 is welded to the pole terminal 12 to form an electrical connection, and the welded position is the electrical connection position between the tab portion 22 and the pole terminal 12. For example, in some embodiments, the electrical connection position between the tab portion 22 and the pole terminal 12 is located on the second end wall 12121 and / or the second side wall 12123, and the tab portion 22 may be welded to at least one of the second end wall 12121 and the second side wall 12123. 【0150】 In the above technical solution, by providing the electrical connection position between the tab portion 22 and the pole terminal 12 on at least one of the second end wall 12121 and the second side wall 12123, the second housing groove 12120 not only serves to accommodate at least a part of the tab portion 22, but the groove wall of the second housing groove 12120 also serves to realize an electrical connection with the tab portion 22. This simplifies the structure of the pole terminal 12 and facilitates the processing of the pole terminal 12. Furthermore, since the through hole 12130 is provided in the second end wall 12121, the tab portion 22 can be easily extended into the second housing groove 12120 through the through hole 12130, simplifying the structure of the tab portion 22, reducing redundancy in the tab portion 22, and lowering the cost of the tab portion 22. Furthermore, the opening direction of the groove opening of the second housing groove 12120 facilitates the electrical connection operation between the tab portion 22 and the groove wall of the second housing groove 12120 via the groove opening of the second housing groove 12120, thereby reducing the difficulty of electrical connection. In addition, by making an electrical connection with the tab portion 22 via the groove wall of the second housing groove 12120, a relatively large area for electrical connection between the tab portion 22 and the electrode terminal 12 can be secured, improving the reliability and stability of the electrical connection, and thereby improving the performance of the battery cell 10. 【0151】 Furthermore, since the electrical connection position between the tab portion 22 and the pole terminal 12 is located within the second housing groove 12120, it is possible to prevent the electrical connection position from protruding outside the pole terminal 12 and occupying the external space of the pole terminal 12. In addition, since the electrical connection position is protected by the pole terminal 12, it is possible to improve the reliability and stability of the electrical connection between the tab portion 22 and the pole terminal 12. 【0152】 Referring again to Figure 15, in some embodiments, the local shape of the tab portion 22 is matched to the local shape of the second end wall 12121, and the two are bonded together to achieve electrical connection, so that the electrical connection position between the tab portion 22 and the second end wall 12121 extends along the length or width direction of the second end wall 12121. For example, if the second end wall 12121 is flat, the local shape of the tab portion 22 may also be flat and bonded to the second end wall 12121, and the bonded portion can be electrically connected by welding or the like. This increases the area of ​​electrical connection and improves the reliability and stability of the electrical connection. 【0153】 The shape of the second end wall 12121 is not limited and can be, for example, a flat plate or an arc-shaped plate. When the second end wall 12121 is a flat plate, it is positioned at a predetermined angle with respect to the axial radius R of the pole terminal 12. For example, it can be a flat plate perpendicular to the axial radius R of the pole terminal 12, or it can be an inclined flat plate not perpendicular to the axial radius R of the pole terminal 12; there are no restrictions on the direction of inclination. 【0154】 For example, referring again to Figure 15, when the second end wall 12121 has a flat plate structure, the angle θ between the second end wall 12121 and the axial radius R of the pole terminal 12 is 90°. That is, along the direction from the through hole 12130 to the second side wall 12123, the second end wall 12121 is arranged at equal intervals from the active material coated portion 21. This facilitates welding between the tab portion 22 and the second end wall 12121. 【0155】 Furthermore, for example, if the angle θ between the second end wall 12121 and the axial radius R of the electrode terminal 12 exceeds 90°, that is, if the second end wall 12121 extends inclined toward the active material coated portion 21 along the direction from the through hole 12130 to the second side wall 12123, this makes it possible to increase the distance over which the tab portion 22 extends along the second end wall 12121, thereby improving the reliability of the electrical connection. For example, the angle θ between the second end wall 12121 and the axial radius R of the electrode terminal 12 can be 90° to 145°, specifically 100°, 110°, 120°, 130°, 140°, etc. This makes the second end wall 12121 easier to process and facilitates electrical connection with the tab portion 22, and also makes it possible to accommodate the tab portion 22 by making relatively sufficient use of the space inside the electrode terminal 12. 【0156】 Furthermore, for example, if the angle θ between the second end wall 12121 and the axial radius R of the pole terminal 12 is less than 90°, that is, along the direction from the through hole 12130 to the second side wall 12123, the second end wall 12121 extends inclined toward the direction away from the active material coated portion 21. 【0157】 This makes it possible to increase the distance over which the tab portion 22 extends along the second end wall 12121, thereby improving the reliability of the electrical connection. For example, the angle θ between the second end wall 12121 and the axial radius R of the pole terminal 12 can be 45° to 90°, specifically 50°, 60°, 70°, 80°, etc. This makes the second end wall 12121 easier to process and facilitates electrical connection with the tab portion 22, and also allows the tab portion 22 to be housed using the space inside the pole terminal 12 relatively sufficiently. 【0158】 Of course, the present application is not limited to these, and in other embodiments of the present application, the electrical connection points between the tab portion 22 and the second end wall 12121 do not necessarily extend along the length or width direction of the second end wall 12121, but can be provided at multiple scattered locations, for example. For example, the tab portion 22 may have multiple parts arranged at intervals, each welded to the second end wall 12121, but details are omitted here. 【0159】 Referring again to Figure 15, and further to Figure 16, Figure 16 is a schematic local cross-sectional view of a battery cell 10 according to several embodiments of the present application. Regardless of the value of the angle θ between the second end wall 12121 and the axial radius R of the electrode terminal 12, in the embodiments of the present application, if the tab portion 22 is electrically connected to the second end wall 12121, a second recessed groove 12122 can be provided in the second end wall 12121 as needed. The second recessed groove 12122 is a recessed groove formed by recessing a part of the second end wall 12121 toward one end closer to the active material coated portion 21. At least a part of the electrical connection position between the tab portion 22 and the second end wall 12121 is located within the second recessed groove 12122. 【0160】 In the above technical solution, the portion of the tab portion 22 located within the second recessed groove 12122 is configured to match the shape of the second recessed groove 12122, and both portions are bonded together to achieve electrical connection. This allows the second recessed groove 12122 to pre-position and constrain the position of the electrical connection of the tab portion 22. This makes it easier to accurately determine the connection position and achieve electrical connection, improving manufacturing efficiency and enhancing the stability and reliability of the electrical connection position, thereby improving the reliability and stability during the charging and discharging operations of the battery cell 10. 【0161】 Referring again to Figure 16, in the embodiment of the present invention, there are no restrictions on the method of connecting the pole terminal 12 and the housing 11; for example, it may be a welded connection or a riveted connection. For example, when the two are joined by riveting, the housing 11 is provided with a mounting hole 113, and the pole terminal 12 is riveted to the mounting hole 113. Of course, even when the two are joined by welding or other methods, a mounting hole 113 can be provided on the housing 11, and the pole terminal 12 can be attached to the mounting hole 113. 【0162】 Referencing Figure 15 again, the second accommodating groove 12120 can be provided corresponding to the position of the mounting hole 113. In other words, by configuring the orthographic projection of the second accommodating groove 12120 to be located within the orthographic projection range of the mounting hole 113 on the projection plane perpendicular to the axial radius R of the pole terminal 12, the depth of the second accommodating groove 12120 can be increased, allowing for the accommodation of more tab portions 22, and thus further reducing the space occupied by the tab portions 22 within the housing 11. 【0163】 In some embodiments, referring again to Figure 15, when a mounting hole 113 is provided in the housing 11 and the pole terminal 12 is mounted in the mounting hole 113, the depth H3 of the second housing groove 12120 is greater than or equal to the minimum distance H4 from the outer end face 123 of the pole terminal to the mounting hole 113 along the axial radius R of the pole terminal 12. 【0164】 The specific shape of the second storage groove 12120 is not limited and may be regular or irregular. Examples include columnar grooves with rectangular, elliptical, or runout cross-sections, trapezoidal grooves with rectangular cross-sections and gradually changing cross-sectional dimensions, hemispherical grooves with circular cross-sections and gradually changing cross-sectional dimensions, or semi-ellipspherical grooves with elliptical cross-sections and gradually changing cross-sectional dimensions. In this specification, "runout shape" refers to a shape in which both short sides of a rectangle are replaced with outwardly convex curves. 【0165】 Therefore, the depth H3 of the second housing groove 12120 refers to the maximum depth that the second housing groove 12120 has along the axial radius R of the electrode terminal 12. Along the axial radius R of the electrode terminal 12, the depth H3 of the second housing groove 12120 is set to be greater than or equal to the minimum distance H4 from the outer end face 123 of the electrode terminal to the mounting hole 113. This is advantageous because it allows for full utilization of the volume of the electrode terminal 12 to secure a large depth in the second housing groove 12120, thereby accommodating more tab portions 22. This further reduces the space occupied by the tab portions 22 within the housing 11, further improving the volumetric energy density of the battery cell 10, and also reduces the redundancy of the tab portions 22 within the housing 11. In addition, the large depth of the second housing groove 12120 allows for the storage of gas generated in the electrode assembly 2, improving the reliability and stability of the battery cell 10, and also allows for the storage of more electrolyte, extending the service life of the battery cell 10. 【0166】 Referring to Figure 16 and then to Figure 17, Figure 17 is a schematic local cross-sectional view of a battery cell 10 according to several embodiments of the present application. In embodiments of the present application, if the housing portion 121 has the second housing groove 12120 of any one of the above embodiments, the battery cell 10 may optionally further include a cover plate 13. The cover plate 13 engages with the electrode terminals 12 to seal the groove opening of the second housing groove 12120 and is electrically connected to the electrode terminals 12. 【0167】 In the above technical solution, by providing a cover plate 13 that seals the groove opening of the second housing groove 12120, leakage of the electrolyte from the housing 11 through the groove opening of the second housing groove 12120 can be suppressed. Furthermore, since the cover plate 13 seals the groove opening of the second housing groove 12120 and is electrically connected to the electrode terminal 12, an indirect electrical connection between the electrode terminal 12 and the bus member can be easily realized via the cover plate 13, and it is advantageous to increase the connection area of ​​the connection part and reduce the connection resistance of the connection part. 【0168】 The fitting method and position between the cover plate 13 and the electrode terminal 12 are not limited, as long as the cover plate 13 can seal the groove opening of the second housing groove 12120. For example, in some embodiments, the cover plate 13 can be welded to the electrode terminal 12. During processing, one method can be adopted in which the tab portion 22 is first passed through the through hole 12130 and welded to the groove wall of the second housing groove 12120, and then the cover plate 13 is welded to the electrode terminal 12 to seal the groove opening of the second housing groove 12120. 【0169】 The specific configuration of the cover plate 13 is not limited. For example, in some selective embodiments, referring to Figure 17, the cover plate 13 includes a first conductive member 131 and a second conductive member 132 made of different materials, the first conductive member 131 is fitted to the pole terminal 12 and electrically connected, and the second conductive member 132 is fitted to the first conductive member 131 and electrically connected. 【0170】 In the above technical solution, by making the cover plate 13 a composite structure and constructing the first conductive member 131 from the same material as the electrode terminal 12, electrical connection between the first conductive member 131 and the electrode terminal 12 can be easily made. For example, the first conductive member 131 can be easily, reliably, and stably connected to the electrode terminal 12 by welding. Furthermore, since the second conductive member 132 is made of a different material from the first conductive member 131, electrical connection to a bus member or the like made of a different material from the electrode terminal 12 can be easily made via the second conductive member 132. For example, the second conductive member 132 can be easily, reliably, and stably connected to a bus member made of the same material as the second conductive member 132 by welding. 【0171】 For example, when the electrode terminal 12 is a negative electrode terminal, and the electrode terminal 12 is a copper column and the bus member is an aluminum piece, the first conductive member 131 can be made of copper and the second conductive member 132 can be made of aluminum. As a result, the electrode terminal 12 and the first conductive member 131 are made of the same material, so welding can be performed effectively, and the second conductive member 132 and the bus member are made of the same material, so welding can be performed effectively. As a result, an indirect electrical connection between the electrode terminal 12 and the bus member can be effectively realized via the cover plate 13. In addition, since the welding of the electrode terminal 12 and the first conductive member 131 is performed with copper materials, the melting fluidity is good, cracks are less likely to occur, and it is advantageous for improving the sealing performance of the welded joint. 【0172】 Referring again to Figure 17, in several selectable examples, the first conductive member 131 is located between the second housing groove 12120 and the second conductive member 132. In the above technical solution, since the first conductive member 131 is located between the second housing groove 12120 and the second conductive member 132, the second housing groove 12120 and the second conductive member 132 are separated. As a result, when the electrolyte in the housing 11 flows into the second housing groove 12120 through the through hole 12130, the first conductive member 131 prevents the electrolyte from coming into contact with the second conductive member 132, thereby solving problems such as corrosion of the second conductive member 132 by the electrolyte. 【0173】 The fitting method between the first conductive member 131 and the second conductive member 132 is not limited. For example, in some embodiments, referring to Figure 17, the first conductive member 131 is provided with a second groove 1311, and the second conductive member 132 is fitted into the second groove 1311. The opening of the second groove 1311 is formed on the surface of the first conductive member 131 away from the second housing groove 12120, thereby exposing the second conductive member 132 from the opening of the second groove 1311. Alternatively, in other embodiments, the connection method between the first conductive member 131 and the second conductive member 132 can be a fastening connection or a fitting connection, etc. 【0174】 Furthermore, when we say that "the second conductive member 132 is 'exposed' from the groove opening of the second recessed groove 1311," "exposed" means that the first conductive member 131 does not cover the second conductive member 132 at the groove opening position of the second recessed groove 1311, and it is not necessarily required that the second conductive member 132 protrudes from the groove opening of the second recessed groove 1311. For example, the second conductive member 132 may be positioned flush with the surface of the first conductive member 131 on the side away from the second housing groove 12120, or the second conductive member 132 may protrude from the surface of the first conductive member 131 on the side away from the second housing groove 12120. 【0175】 In the above technical solution, on the one hand, by fitting the second conductive member 132 into the first conductive member 131, the difficulty of assembling the first conductive member 131 and the second conductive member 132 can be reduced, and the stability and convenience of fitting the first conductive member 131 and the second conductive member 132 can be improved. Also, by reducing the thickness of the cover plate 13 and reducing the space occupied by the cover plate 13, it is possible to improve the space utilization rate of the battery cell 10. On the other hand, since the second conductive member 132 can be exposed on the surface of the first conductive member 131 away from the second housing groove 12120 through the groove opening of the second recess 1311, it is advantageous for realizing an electrical connection between the second conductive member 132 and the bus member outside the electrode terminal 12. 【0176】 Furthermore, since the groove opening of the second groove 1311 is formed on the surface of the first conductive member 131 away from the second housing groove 12120, it is shown that the second groove 1311 opens in a direction away from the active material coated portion 21. As a result, the portion of the first conductive member 131 that defines the groove wall of the second groove 1311 is positioned between the second housing groove 12120 and the second conductive member 132, separating the second housing groove 12120 and the second conductive member 132, thereby preventing the electrolyte that flows into the second groove 1311 from coming into contact with the second conductive member 132 and reducing electrolyte leakage. 【0177】 Of course, in other embodiments, the cover plate 13 does not necessarily have to be a composite structure made of multiple materials, and in other embodiments of the present invention, the entire cover plate 13 can be a non-composite structure made of the same material. For example, this could be the case when it is made to fit the positive electrode terminal 12, but details are omitted here. 【0178】 Referring again to Figure 17, the cover plate 13 is further fitted into the groove of the second housing groove 12120. In the above technical solution, by fitting the cover plate 13 into the second housing groove 12120, the difficulty of assembling the cover plate 13 and the pole terminal 12 is reduced, the assembly stability of the cover plate 13 and the pole terminal 12, and the reliability and convenience of the connection are improved, and the space occupied by the cover plate 13 outside the pole terminal 12 can be reduced. Furthermore, since the cover plate 13 is fitted into the groove of the second housing groove 12120, sufficient space can be secured within the second housing groove 12120 to accommodate the tab portion 22. 【0179】 In other embodiments of this application, the fitting method between the cover plate 13 and the electrode terminal 12 is not necessarily limited to fitting within the second housing groove 12120. The cover plate 13 can also be placed directly over the outside of the electrode terminal 12, that is, directly covering the groove opening of the second housing groove 12120. This embodiment is not limited to this one, as long as it can be easily combined with the bus components of the battery 100. 【0180】 In some embodiments, the housing 11 includes a housing body 111 and a housing cover 112, the housing body 111 having an opening 1110, and the housing cover 112 covering the opening 1110. Furthermore, a terminal 12 is provided on the wall portion of the housing cover 112 and / or the housing body 111 facing the opening 1110. 【0181】 For example, all the terminals 12 can be provided on the housing cover 112. For instance, one terminal 12 can be provided on the housing cover 112, while the remaining terminals 12 are provided on the housing body 111. Because the housing cover 112 is relatively small, the size of the mold and jig can be reduced, which is advantageous for cost reduction. 【0182】 Of course, at least one electrode terminal 12 can also be provided on the wall of the housing body 111 facing the opening 1110. With this method, the electrode assembly 2 is inserted into the housing body 111 along the opening 1110, and the tab portion 22 directly faces the electrode terminal 12, making the connection between the tab portion 22 and the electrode terminal 12 relatively easy and improving the assembly efficiency of the battery cell 10. 【0183】 Referring again to Figure 2, according to several embodiments of the present application, the present application provides a battery cell 100. The battery 100 includes a battery cell 10 according to any one of the above embodiments. 【0184】 In the technical solution of the embodiment of the present invention, applying the above-mentioned battery cell 10 is advantageous in improving the capacity of the battery 100, enhancing the reliability of the battery 100, and reducing the difficulty of manufacturing. 【0185】 Referring again to Figure 1, according to some embodiments of the present application, the present application further provides a power consumption device 1000. The power consumption device 1000 includes a battery cell 10 according to any one of the above technical solutions, or a battery 100 according to any one of the above technical solutions, the battery 100 being used to supply power to the power consumption device 1000. The power consumption device 1000 may be any of the above devices or systems to which the battery 100 is applied. 【0186】 In the technical solution according to the embodiment of the present application, the reliability of the power consumption device 1000 can be improved by applying the battery 100. 【0187】 Referring again to Figures 8 to 14, and further to Figure 24, Figure 24 is a manufacturing flowchart of an electrode assembly 2 according to several embodiments of the present application, and the present application provides a method for manufacturing an electrode assembly 2. 【0188】 The method for manufacturing an electrode assembly is: The steps include providing raw materials for the electrode assembly, The steps include stacking multiple tab pieces of the electrode assembly, The steps include: welding the overlapping regions of multiple tab pieces to form a first welded portion of the tab; The method includes the step of welding the misaligned regions of multiple tab pieces to form a second weld of the tab portion, wherein the second weld is located at one end away from the active material coated portion of the first weld. 【0189】 Specifically, the overlapping region Z1 may be welded first to form the first welded portion 2211, and then the portion of the displacement region Z2 that is away from the active material coated portion 21 may be welded to form the second welded portion 2212, or the portion of the displacement region Z2 that is away from the active material coated portion 21 may be welded first to form the second welded portion 2212, and then the overlapping region Z1 may be welded to form the first welded portion 2211. 【0190】 In the technical solution according to the embodiment of the present application, the area of ​​the welding region of the multiple tab pieces 221 can be increased by welding the overlapping region Z1 of the multiple tab pieces 221 to form a first welded portion 2211, and welding the portion of the displacement region Z2 of the multiple tab pieces 221 that is away from the active material coated portion 21 to form a second welded portion 2212. On the one hand, this is advantageous in increasing the utilization rate of the tab portion 22, improving the capacity of the battery cell 10, and suppressing the temperature rise during overcurrent. On the other hand, when welding the tab portion 22 to the electrode terminal 12, the second welded portion 2212 can play a role in supporting the welding press nozzle more than the multiple bulging tab pieces, thus reducing the problem of welding defects caused by the welding press nozzle being pressed against the bulging region of the multiple tab pieces 221, as seen in the prior art. Furthermore, it is possible to reduce the cutting requirements of the tab portion 22 after welding, saving costs, while also improving the rapid charging performance of the battery cell 10. 【0191】 Referring again to Figures 8 to 11, the step of welding the overlapping region Z1 of the multiple tab pieces 221 involves sandwiching the overlapping region Z1 of the multiple tab pieces 221 between the first ultrasonic welding anvil 81 and the first ultrasonic welding horn 82, and welding the overlapping region Z1 of the tab portion 22 using the ultrasonic welding method to form the first welded portion 2211 of the tab portion 22. 【0192】 Specifically, after pairing multiple tab pieces 221, the multiple tab pieces 221 are stacked and arranged. The stacked multiple tab pieces 221 have an overlapping region Z1 and a misaligned region Z2. The overlapping region Z1 is sandwiched between the first ultrasonic welding anvil 81 and the first ultrasonic welding horn 82, and any two adjacent tab pieces 221 melt due to friction, thereby welding the overlapping region Z1 of the multiple tab pieces 221 together to form a first welded portion 2211. 【0193】 In the above technical solution, since the first welded portion 2211 is formed by ultrasonic welding, the welding speed and welding efficiency are improved, and the surface quality of the overlapping region Z1 after welding is improved. Furthermore, the welding process is clean, stable, and reliable, and energy consumption is reduced. 【0194】 Referring again to Figures 12 to 14, the step of welding the displacement region Z2 of the multiple tab pieces 221 involves sandwiching the displacement region Z2 of the multiple tab pieces 221 between the second ultrasonic welding anvil 91 and the second ultrasonic welding horn 92, and welding the displacement region Z2 of the tab portion 22 using the ultrasonic welding method to form the second welded portion 2212 of the tab portion 22. 【0195】 Specifically, the portion of the displacement region Z2 away from the active material coated portion 21 is sandwiched between the second ultrasonic welding anvil 91 and the second ultrasonic welding horn 92, and any two adjacent tab pieces 221 melt due to friction, thereby welding together the portions of the displacement region Z2 of multiple tab pieces 221 away from the active material coated portion 21, and forming the second welded portion 2212. 【0196】 In the above technical solution, since the second weld 2212 is formed by ultrasonic welding, the welding speed and welding efficiency are improved, and the surface quality of the overlapping region Z1 after welding is improved. Furthermore, the welding process is clean, stable, and highly reliable, and energy consumption is reduced. 【0197】 Referring again to Figures 12-14, one of the opposing surfaces of the second ultrasonic welding anvil 91 and the second ultrasonic welding horn 92 extends along the height direction of the tab portion 22, while the other of the opposing surfaces of the second ultrasonic welding anvil 91 and the second ultrasonic welding horn 92 is inclined with respect to the height direction of the tab portion 22. 【0198】 In other words, the first surface 2214 of the second welded portion 2212 formed by welding may be flush with the first welded portion 2211, and when welding the tab portion 22 and the electrode terminal 12, it becomes possible to use a larger welding press nozzle. Part of the welding press nozzle can be pressed against the first welded portion 2211 and the other part against the second welded portion 2212. That is, the first welded portion 2211 and the second welded portion 2212 can support the welding press nozzle simultaneously. This reduces the difficulty of the welding work and reduces the problem of welding defects that occur when the welding press nozzle is pressed against the bulging areas of multiple tab pieces, as seen in the conventional technology. In addition, it is possible to reduce costs by relaxing the cutting requirements of the tab portion after welding, while also improving the rapid charging performance of the battery cell 10. 【0199】 In the above technical solution, by applying the second ultrasonic welding anvil 91 and the second ultrasonic welding horn 92, ultrasonic welding can be performed on the displacement region Z2. This forms a predetermined second welded portion 2212. On the one hand, it is possible to easily determine whether or not cutting is necessary in subsequent processes, improving the convenience of cutting work, and on the other hand, the difficulty of welding is reduced, welding defects are suppressed, and welding quality is improved. 【0200】 In some embodiments, the angle α between the opposing surfaces of the second ultrasonic welding anvil 91 and the second ultrasonic welding horn 92 is smaller than the angle β between the two opposing wall surfaces of the shear region Z2. By setting it in this way, the second ultrasonic welding anvil 91 and the second ultrasonic welding horn 92 can reliably grip the portion of the shear region Z2 that is away from the active material coated portion 21, thereby improving welding quality. 【0201】 Specifically, the overlapping region Z1 is welded to form the first welded portion 2211, and then the portion of the displacement region Z2 away from the active material coated portion 21 is welded using the second ultrasonic welding anvil 91 and the second ultrasonic welding horn 92 to form the second welded portion 2212. Then, it is possible to select whether or not to cut the second welded portion 2212 as needed, and further welding residue can be removed from the cross-section by methods such as brushing or vacuum suction. 【0202】 In some other embodiments, the misaligned region Z2 obtained by stacking a plurality of tab pieces 221 includes an end misaligned region Z21, the end misaligned region Z21 is located at one end of the overlapping region Z1 away from the active material coated portion 21, and the steps prior to welding the end misaligned region Z21 with the second ultrasonic welding anvil 91 and the second ultrasonic welding horn 92 further include the step of bending a first portion of the end misaligned region Z21 toward a second portion which will be the remainder of the end misaligned region Z21 in a direction toward the active material coated portion 21, and then welding the two portions together in an overlapping state to form a second welded portion 2212. 【0203】 In the above technical solution, the displacement region Z2 is located on at least one of the two sides of the overlapping region Z1 and is welded to form a third welded portion 2213. On the one hand, this increases the area of ​​the welded region of the multiple tab pieces 221 and improves the utilization rate of the tab portion 22, which is advantageous for improving the capacity of the battery cell 10 and suppressing temperature rise during overcurrent. On the other hand, it reduces the problem of welding defects caused by the welding press nozzle being pressed against the bulging regions of the multiple tab pieces 221, as seen in the prior art, and makes it easier for the tab portion 22 to pass through the through hole in the electrode terminal 12. 【0204】 In some embodiments, the method for manufacturing the electrode assembly 2 further includes the step of welding the misaligned regions Z2 of a plurality of tab pieces 221 to form a third weld 2213 of the tab portion 22, the third weld 2213 being located on at least one side of the first weld 2211. 【0205】 Specifically, the displacement region Z2 formed by stacking multiple tab pieces 221 includes two lateral displacement regions Z22, the two lateral displacement regions Z22 are located on both sides in the width direction of the overlapping region Z1, and at least one of the lateral displacement regions Z22 is welded to form a third welded portion 2213. 【0206】 In the above technical solution, the displacement region Z2 is located on at least one of the two sides of the overlapping region Z1 and is welded to form a third welded portion 2213. On the one hand, this increases the area of ​​the welded region of the multiple tab pieces 221 and improves the utilization rate of the tab portion 22, which is advantageous for improving the capacity of the battery cell 10 and suppressing temperature rise during overcurrent. On the other hand, it reduces the problem of welding defects caused by the welding press nozzle being pressed against the bulging regions of the multiple tab pieces 221, as seen in the prior art, and makes it easier for the tab portion 22 to pass through the through hole in the electrode terminal 12. 【0207】 Referring to Figure 17, in some further embodiments, the steps prior to forming the third weld 2213 further include bending a first portion of at least one lateral displacement region Z22 toward the second portion which is the remainder of the lateral displacement region Z22, in a direction toward the active material coated portion 21, and then welding the two portions together in an overlapping state to form the third weld 2213. 【0208】 Finally, it should be noted that the above embodiments are merely for illustrating, and not limiting, the technical solutions of the present application. While the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that it is still possible to modify the technical solutions described in the above embodiments, or to substitute some or all of their technical features, and such modifications or substitutions do not cause the substance of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included within the scope of the claims and specification of the present application. In particular, unless there is a structural inconsistency, the technical features mentioned in each embodiment can all be combined in any manner. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions included in the claims. [Explanation of symbols] 【0209】 1000 power consuming devices 100 batteries 200 controllers 300 motor 10 battery cells 20 cabinets 201 First cabinet 202 Second enclosure 11 Housing 111 Housing body 1110 Aperture 112 Housing Cover 113 Mounting holes 12-pin terminal 121 Storage Unit 12110 First storage groove 12111 End Wall No. 1 12112 First submerged trench 12113 First side wall 12120 Second containment groove 12121 Second End Wall 12122 Second Submerged Trench 12123 Second side wall 12130 Through hole 122 Pole terminal inner end surface 123 Pole terminal outer end surface 126 1st groove 127 Interval 13 Cover Plate 131 First conductive member 1311 Second groove 132 Second conductive member 2 Electrode Assembly 21 Active material coated section 22 Tab section 221 tabs Z1 overlapping region Z2 displacement region Z21 Edge displacement region Z22 Lateral displacement region 2211 No. 1 Weld 2212 Second Weld Section 2213 Third Weld 2214 1st surface 2215 2nd surface 3 holders 314 Through-hole 4. Insulating material 6. Explosion-proof valve 7 groove cover 81. First ultrasonic welding anvil 82. First ultrasonic welding horn 91 Second ultrasonic welding anvil 92. Second ultrasonic welding horn Z 1st direction X 2nd direction Y Third direction R pole terminal axial direction

Claims

[Claim 1] Active material coated section, An electrode assembly comprising a tab portion connected to the active material coated portion, wherein the tab portion includes a plurality of stacked tab pieces, the stacked plurality of tab pieces having overlapping regions and offset regions, the overlapping regions being welded to form a first welded portion, and the offset regions being welded to form a second welded portion. [Claim 2] The electrode assembly according to claim 1, wherein the first welded portion is connected to the second welded portion. [Claim 3] Along the width direction of the tab portion, the ratio of the width size of the first weld to the width size of the second weld is in the range of 0.8 to 1.2, and / or Along the width direction of the tab portion, the ratio of the width size of the first welded portion to the width size of the tab portion is in the range of 0.6 to 1. Along the height direction of the tab portion, the ratio of the height sizes of the second weld and the first weld is 0.08 to 0.2, and / or The electrode assembly according to claim 1, wherein the ratio of the height size of the first welded portion to the tab portion along the height direction of the tab portion is 0.45 to 0.

65. [Claim 4] The electrode assembly according to any one of claims 1 to 3, wherein the height size of the second welded portion is 1 mm to 2 mm along the height direction of the tab portion. [Claim 5] The electrode assembly according to claim 1, wherein the thickness of the second weld gradually decreases in the direction away from the first weld. [Claim 6] The electrode assembly according to claim 5, wherein the second welded portion has two opposing first and second surfaces, and at least one of the first and second surfaces is inclined with respect to the height direction of the tab portion. [Claim 7] The electrode assembly according to claim 6, wherein the maximum distance between the first surface and the second surface is 0.5 mm to 1 mm. [Claim 8] The electrode assembly according to claim 6 or 7, wherein the first surface extends in the height direction of the tab portion, the second surface is provided at an inclination with respect to the height direction of the tab portion, and the distance between the first surface and the second surface gradually decreases in the direction away from the first weld portion. [Claim 9] The electrode assembly according to claim 8, wherein the angle between the first surface and the second surface is 10° to 45°. [Claim 10] The electrode assembly according to any one of claims 1 to 3, wherein the first welded portion and the second welded portion are each formed by ultrasonic welding. [Claim 11] The electrode assembly according to any one of claims 1 to 3, wherein the displacement region is located on at least one of the two sides of the overlapping region and is welded to form a third weld. [Claim 12] A housing on which polarity terminals are provided, A battery cell comprising an electrode assembly provided within the housing, the electrode assembly according to any one of claims 1 to 3, wherein the tab portion is connected to the electrode terminal. [Claim 13] The battery cell according to claim 12, wherein the electrode terminal is provided with a housing portion, and at least a portion of the tab portion is inserted into the housing portion and welded to the electrode terminal. [Claim 14] The battery cell according to claim 13, wherein the housing portion includes a first housing groove, the surface of the electrode terminal facing the active material coated portion is the inner end face of the electrode terminal, the groove opening of the first housing groove is formed on the inner end face of the electrode terminal, and at least a portion of the tab portion is housed in the first housing groove. [Claim 15] The battery cell according to claim 13, wherein the housing portion includes a second housing groove, the surface of the electrode terminal away from the active material coated portion is the outer end surface of the electrode terminal, the groove opening of the second housing groove is formed on the outer end surface of the electrode terminal, the second housing groove communicates with the inside of the housing through a through hole, and the tab portion is arranged with the through hole drilled and at least a part of it is housed in the second housing groove. [Claim 16] The battery cell according to claim 12, wherein the housing includes a housing cover and a housing body having an opening, the housing cover is placed over the opening, and the electrode terminals are provided on the wall of the housing cover and / or the housing body facing the opening. [Claim 17] A battery comprising the battery cell described in claim 12. [Claim 18] A power consumption device including a battery as described in claim 17. [Claim 19] The steps include providing raw materials for the electrode assembly, The steps include: forming a tab portion by stacking multiple tab pieces of the electrode assembly; The steps include: welding the overlapping region of the tab portion to form a first welded portion; A method for manufacturing an electrode assembly, comprising the step of welding the misaligned region of the tab portion to form a second weld, wherein the second weld is located at one end of the first weld that is away from the active material coated portion. [Claim 20] The step of welding the overlapping region of the tab portion is, A method for manufacturing an electrode assembly according to claim 19, comprising the step of sandwiching the overlapping region of the tab portion between a first ultrasonic welding anvil and a first ultrasonic welding horn, and welding the overlapping region of the tab portion by an ultrasonic welding method to form the first welded portion. [Claim 21] The step of welding the misaligned area of ​​the tab portion is, A method for manufacturing an electrode assembly according to claim 19 or 20, comprising the step of sandwiching the misaligned region of the tab portion between a second ultrasonic welding anvil and a second ultrasonic welding horn, and welding the misaligned region of the tab portion by an ultrasonic welding method to form the second welded portion. [Claim 22] A method for manufacturing an electrode assembly according to claim 21, wherein one of the opposing surfaces of the second ultrasonic welding anvil and the second ultrasonic welding horn extends along the height direction of the tab portion and the other is inclined with respect to the height direction of the tab portion. [Claim 23] The method for manufacturing an electrode assembly according to claim 21, wherein the angle between the opposing surfaces of the second ultrasonic welding anvil and the second ultrasonic welding horn is smaller than the angle between the two opposing wall surfaces provided in the displacement region.

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