Electrode assembly and preparation method thereof, battery monomer, battery and electric device

Abstract

The invention discloses an electrode assembly and a preparation method thereof, a battery monomer, a battery and a power utilization device. The electrode assembly includes: an active material coating portion; the electrode lug part comprises a plurality of electrode lug pieces which are arranged in a stacked mode, the plurality of electrode lug pieces are provided with an overlapping area and a dislocation area after being stacked, the overlapping area is welded to form a first welding part, and the dislocation area is welded to form a second welding part at least at the position away from the active material coating part. In the technical scheme of the embodiment of the invention, on one hand, the utilization rate of the tab part is improved, the capacity of the single battery is favorably improved, and the over-current temperature rise is reduced, and on the other hand, the second welding part can play a role in supporting the welding pressure nozzle compared with a plurality of fluffy tab pieces, so that the problem of welding defects is reduced, and the production efficiency is improved. Compared with the prior art, the cutting requirement on the tab part after welding is reduced, the cost is saved, the fast charging performance and the assembling efficiency of the battery monomer are improved, and the tab part is not easily scratched by the hole wall of the through hole structure.

Description

Technical Field

[0001] The present application relates to the field of batteries, and in particular to an electrode assembly and a preparation method thereof, a battery cell, a battery and an electrical device. Background Art

[0002] Energy conservation and emission reduction are the key to the sustainable development of the automobile industry. Electric vehicles have become an important part of the sustainable development of the automobile industry due to their advantages in energy conservation and environmental protection. For electric vehicles, battery technology is an important factor related to their development. The utilization rate of the ear part of the electrode assembly in the related technology is low, resulting in a reduction in the capacity of the battery cell. Summary of the invention

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

[0004] In a first aspect, the present application provides an electrode assembly, comprising: an active material coating portion; and a pole ear portion connected to the active material coating portion, the pole ear portion comprising a plurality of pole ear sheets stacked together, the plurality of pole ear sheets having overlapping areas and misaligned areas after being stacked, the overlapping areas being welded to form a first welding portion, and the misaligned areas being welded at least at a position away from the active material coating portion to form a second welding portion.

[0005] In the technical solution of the embodiment of the present application, by welding the overlapping areas of multiple pole lugs to form a first welding portion, and welding the dislocated areas of multiple pole lugs away from the active material coating portion to form a second welding portion, the area of ​​the welding area of ​​multiple pole lugs can be increased. On the one hand, the utilization rate of the pole lug is improved, which is beneficial to improve the capacity of the battery cell and reduce the overcurrent temperature rise. On the other hand, when the pole lug is welded to the pole, the second welding portion can better support the welding nozzle than the fluffy pole lugs, and wrinkles and other problems will not occur, reducing the problem of welding defects caused by the welding nozzle in the related art being pressed onto the fluffy area of ​​multiple pole lugs, reducing the cutting requirements for the pole lug after welding, saving costs, and improving the fast charging performance of the battery cell. In addition, by welding the dislocated area to form the second welding portion, the efficiency of the pole lug passing through the through-hole structure can be improved, thereby improving the assembly efficiency of the battery cell, and making the pole lug less likely to be scratched by the hole wall of the through-hole structure.

[0006] In some embodiments, the first welding portion and the second welding portion are connected and arranged. In the above technical scheme, compared with the fluffy multiple pole lugs, the connected first welding portion and the second welding portion can, on the one hand, improve the stiffness of the multiple pole lugs after welding to a certain extent, so that the pole lugs are not easily scratched by the hole walls of the through-hole structure, thereby improving the efficiency of the pole lugs passing through the through-hole structure. On the other hand, the second welding portion formed after welding is less likely to collapse under pressure relative to the first welding portion, and can effectively support the welding nozzle without problems such as wrinkles, thereby reducing the problem of welding defects caused by the welding nozzle in the related technology being pressed onto the fluffy areas of the multiple pole lugs.

[0007] In some embodiments, along the width direction of the pole ear portion, the ratio of the width dimension of the first welding portion to the width dimension of the second welding portion is in the range of 0.8-1.2; and / or, along the width direction of the pole ear portion, the ratio of the width dimension of the first welding portion to the width dimension of the pole ear portion is in the range of 0.6-1; along the height direction of the pole ear portion, the ratio of the height dimension of the second welding portion to the first welding portion is 0.08-0.2; and / or, along the height direction of the pole ear portion, the ratio of the height dimension of the first welding portion to the pole ear portion is 0.45-0.65. In the above technical solution, the area of ​​the welding area of ​​multiple pole ear sheets can be increased, the utilization rate of the pole ear portion can be improved, which is beneficial to increase the capacity of the battery cell, reduce the overcurrent temperature rise, and can also reduce the problem of welding defects caused by the welding nozzle in the related technology being pressed into the fluffy area of ​​multiple pole ear sheets.

[0008] In some embodiments, along the height direction of the pole ear portion, the height dimension of the second welding portion is 1mm-2mm. In the above technical solution, by limiting the height dimension of the second welding portion to meet the above conditions, on the one hand, the proportion of the misaligned area of ​​the multiple pole ear sheets can be reduced as much as possible, the qualified rate of the electrode assembly can be improved, and it is beneficial to improve the quality of the battery cell. On the other hand, based on the misalignment of the multiple pole ear sheets, the misaligned area is welded, which can increase the area of ​​the welding area of ​​the multiple pole ear sheets and reduce the problem of welding defects caused by the welding nozzle in the related art being pressed into the fluffy area of ​​the multiple pole ear sheets.

[0009] In some embodiments, the thickness of the second welding portion gradually decreases in a direction away from the first welding portion, which makes cutting easier.

[0010] In some embodiments, the second welding portion has two oppositely disposed first and second surfaces, and at least one of the first and second surfaces is inclined relative to the height direction of the pole ear portion. In the above technical solution, the second welding portion is formed in the above form, which facilitates the subsequent decision on whether to cut according to needs, thereby improving the convenience of cutting.

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

[0012] In some embodiments, the first surface extends along the height direction of the pole ear portion, the second surface is inclined relative to the height direction of the pole ear portion, and the distance between the first surface and the second surface gradually decreases in the direction away from the first welding portion. In the above technical solution, the second welding portion is formed in the above form, which, on the one hand, facilitates the subsequent decision on whether to cut according to needs and improves the convenience of cutting, and on the other hand, can reduce the difficulty of welding, reduce welding defects, and improve welding quality.

[0013] In some embodiments, the angle between the first surface and the second surface is 10°-45°. It is convenient to use the ultrasonic seat and the ultrasonic welding head to weld the part of the dislocation area away from the active material coating part, thereby improving welding convenience and welding quality.

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

[0015] In some embodiments, the misaligned area is located on at least one side of the two sides of the overlapping area and is welded to form a third welded portion. In the above technical solution, by welding the misaligned area on at least one side of the two sides of the overlapping area to form a third welded portion, on the one hand, the area of ​​the welding area of ​​the multiple pole tabs can be increased, the utilization rate of the pole tabs can be improved, which is beneficial to increase the capacity of the battery cell and reduce the overcurrent temperature rise. On the other hand, it can reduce the problem of welding defects caused by the welding nozzle in the related technology being pressed onto the fluffy area of ​​the multiple pole tabs, and it can also facilitate the pole tabs to pass through the through-holes on the pole column.

[0016] In a second aspect, the present application provides a battery cell, comprising: a shell, the shell being provided with a pole; an electrode assembly, the electrode assembly being arranged in the shell, the pole ear being connected to the pole, and the electrode assembly being the electrode assembly described in any of the above embodiments.

[0017] In the technical solution of the embodiment of the present application, by adopting the above-mentioned electrode assembly, on the one hand, the utilization rate of the pole ear portion is improved, which is beneficial to improving the capacity of the battery cell and reducing the over-current temperature rise; on the other hand, when welding the pole ear portion to the pole, the second welding portion can better support the welding nozzle than the fluffy multiple pole ear sheets, and there will be no problems such as wrinkles, reducing the problem of welding defects caused by the welding nozzle in the related technology being pressed onto the fluffy area of ​​multiple pole ear sheets, thereby improving the reliability of the battery cell, reducing the cutting requirements for the pole ear portion after welding, thereby reducing the production difficulty of the battery cell, saving costs, and improving the fast charging performance of the battery cell.

[0018] In some embodiments, the pole is provided with a receiving portion, and at least part of the pole ear extends into the receiving portion and is welded to the pole. The hollow structure of the receiving portion can reduce the weight of the pole to a certain extent, so as to improve the weight energy density of the battery cell and the battery. On the other hand, the pole ear can be accommodated in the receiving portion, which improves the assembly efficiency of the pole ear, saves the space occupied by the pole ear, and makes full use of the space of the battery cell, so that the cooperation between the bracket and the pole, and between the bracket and the pole ear are tighter and more reliable, so that the structure of the battery cell is more compact, which is more conducive to the improvement of the energy density of the battery cell.

[0019] In some embodiments, the accommodating portion includes a first accommodating groove, the surface of the pole facing the active material coating portion is the inner end face of the pole, the notch of the first accommodating groove is formed on the inner end face of the pole, and at least part of the pole ear portion is accommodated in the first accommodating groove. In the above technical scheme, on the one hand, the first accommodating groove provided on the pole can reduce the weight of the pole to a certain extent, so as to improve the weight energy density of the battery cell and the battery; on the other hand, since the notch of the first accommodating groove is formed on the inner end face of the pole, and the inner end face of the pole is the surface of the pole close to the active material coating portion, the first accommodating groove can be opened toward the active material coating portion, thereby facilitating the pole ear portion to extend into the first accommodating groove, thereby improving assembly efficiency. Moreover, this form of first accommodating groove is easy to process and improves production efficiency.

[0020] In some embodiments, the accommodation portion includes a second accommodation groove, the surface of the pole away from the active material coating portion is the outer end face of the pole, the notch of the second accommodation groove is formed on the outer end face of the pole, the second accommodation groove is connected to the interior of the shell through a perforation, and the pole ear portion is penetrated through the perforation and at least partially accommodated in the second accommodation groove. In the above technical solution, on the one hand, the pole is provided with a second accommodation groove, which can reduce the weight of the pole to a certain extent, so as to improve the weight energy density of the battery cell and the battery; on the other hand, since the notch of the second accommodation groove is formed on the outer end face of the pole, and the outer end face of the pole is the surface of the pole away from the active material coating portion, the second accommodation groove can be opened in the direction away from the active material coating portion, so that when at least part of the pole ear portion is accommodated in the second accommodation groove, the pole ear portion can be easily stored and arranged through the notch of the second accommodation groove, and the electrical connection operation between the pole ear portion and the pole can be easily realized through the notch of the second accommodation groove, thereby reducing the difficulty of producing the battery cell and improving the production efficiency of the battery cell.

[0021] In some embodiments, the shell includes a shell cover and a shell body with an opening, the shell cover covers the opening, and the pole is provided on the wall of the shell cover and / or the shell body opposite to the opening. The pole is provided on the shell cover, and since the size of the shell cover is relatively small, the size of the mold or the fixture can be reduced, which is conducive to reducing costs; the pole is provided on the wall of the shell body opposite to the opening, the electrode assembly enters the shell body along the opening, and the pole ear directly faces the pole, so that the pole ear can be connected with the pole relatively easily, thereby improving the assembly efficiency of the battery cell.

[0022] In a third aspect, the present application provides a battery, comprising the battery cell described in any of the above embodiments.

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

[0024] In a fourth aspect, the present application provides an electrical device, comprising the battery described in any of the above embodiments.

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

[0026] In a fifth aspect, the present application provides a method for preparing an electrode assembly, comprising the following steps: providing incoming materials for the electrode assembly; stacking a plurality of pole tabs of the electrode assembly; welding overlapping areas of the plurality of pole tabs to form a first welding portion of the pole tab; welding staggered areas of the plurality of pole tabs to form a second welding portion of the pole tab, wherein the second welding portion is located at an end of the first welding portion away from the active material coating portion.

[0027] In the technical solution of the embodiment of the present application, the overlapping areas of multiple pole lugs are welded to form a first welding portion, and the offset areas of multiple pole lugs are welded away from the position of the active material coating portion to form a second welding portion, so that the area of ​​the welding region of the multiple pole lugs can be increased. On the one hand, the utilization rate of the pole lug portion is improved, which is beneficial to improve the capacity of the battery cell and reduce the over-current temperature rise. On the other hand, when the pole lug portion is welded to the pole, the second welding portion can better support the welding nozzle than the fluffy multiple pole lugs, thereby reducing the problem of welding defects caused by the welding nozzle in the related technology being pressed onto the fluffy area of ​​multiple pole lugs, reducing the cutting requirements for the pole lug portion after welding, saving costs, and improving the fast charging performance of the battery cell.

[0028] In some embodiments, the welding of the overlapping regions of the plurality of pole tabs comprises: sandwiching the overlapping regions of the plurality of pole tabs between a first ultrasonic welding seat and a first ultrasonic welding head, and welding the overlapping regions of the pole tabs by ultrasonic welding to form the first welding portion. In the above technical solution, since the first welding portion is formed by ultrasonic welding, the welding speed and welding efficiency can be improved, the surface quality of the overlapping region after welding can be improved, and the welding process is clean, stable, reliable, and has low energy consumption.

[0029] In some embodiments, the welding of the dislocated regions of the plurality of pole tabs comprises: clamping the dislocated regions of the plurality of pole tabs between a second ultrasonic welding seat and a second ultrasonic welding head, so as to form the second welding portion by ultrasonic welding the dislocated regions of the pole tabs. In the above technical solution, since the second welding portion is formed by ultrasonic welding, the welding speed and welding efficiency can be improved, the surface quality of the overlapping region after welding can be improved, and the welding process is clean, stable, reliable, and has low energy consumption.

[0030] In some embodiments, one of the surfaces of the second ultrasonic welding seat and the second ultrasonic horn facing each other extends along the height of the pole ear portion and the other is arranged obliquely relative to the height direction of the pole ear portion. In the above technical solution, by using the second ultrasonic welding seat and the second ultrasonic horn, the dislocation area can be ultrasonically welded to form a preset second welding portion, which is convenient for deciding whether to cut according to the needs later and improves the convenience of cutting. On the other hand, it can reduce the difficulty of welding, reduce welding defects, and improve welding quality.

[0031] In some embodiments, the angle between the surfaces of the second ultrasonic welding base and the second ultrasonic horn facing each other is smaller than the angle between the two oppositely disposed wall surfaces of the misaligned region. In this way, the second ultrasonic welding base and the second ultrasonic horn can clamp the portion of the misaligned region away from the active material coating portion, thereby improving the welding quality.

[0032] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0034] Figure 1 A schematic diagram of the structure of a vehicle provided in some embodiments of the present application;

[0035] Figure 2 An exploded view of the structure of a battery provided in some embodiments of the present application;

[0036] Figure 3 A three-dimensional diagram of a battery cell provided for some embodiments of the present application;

[0037] Figure 4 A structural cross-sectional view of a battery cell provided in some embodiments of the present application;

[0038] Figure 5 A partial enlarged view of an electrode assembly provided in some embodiments of the present application;

[0039] Figure 6 A side view of an electrode assembly provided for some embodiments of the present application;

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

[0041] Figure 8 A schematic diagram of the structure of the electrode ear portion of the electrode assembly provided in some embodiments of the present application before pairing;

[0042] Fig. 9 A schematic diagram of the structure of the electrode ear portion of the electrode assembly provided in some embodiments of the present application after being matched with the first ultrasonic welding seat and the first ultrasonic welding head;

[0043] Fig.10 A schematic diagram of the structure of the overlapping area of ​​the pole ear portion of the electrode assembly provided in some embodiments of the present application before welding with the first ultrasonic welding seat and the first ultrasonic welding head;

[0044] Fig.11 A schematic diagram of the structure of an electrode assembly provided in some embodiments of the present application, wherein the overlapping area of ​​the pole ear portion is ultrasonically welded to form a first welding portion;

[0045] Fig.12 A schematic diagram of the structure of the misaligned area of ​​the pole ear portion of the electrode assembly provided in some embodiments of the present application before welding with the second ultrasonic welding seat and the second ultrasonic welding head;

[0046] Fig.13 A schematic diagram of the structure of an electrode assembly provided in some embodiments of the present application, wherein a dislocated area of ​​the electrode ear portion away from the active material coating portion is ultrasonically welded to form a second welding portion;

[0047] Fig.14 A schematic diagram of the structure of an electrode assembly provided in some embodiments of the present application;

[0048] Fig.15 A partial enlarged view of an electrode assembly provided in some other embodiments of the present application;

[0049] Fig.16 A top view of an electrode assembly provided in some other embodiments of the present application;

[0050] Fig.17 A schematic cross-sectional view of an electrode ear portion of an electrode assembly provided in some other embodiments of the present application;

[0051] Fig.18 A partial cross-sectional schematic diagram of a battery cell provided in some embodiments of the present application;

[0052] Fig.19 A partial cross-sectional schematic diagram of a battery cell provided in some embodiments of the present application;

[0053] Fig. 20 A partial cross-sectional schematic diagram of a battery cell provided in some embodiments of the present application;

[0054] Fig.21 A partial cross-sectional schematic diagram of a battery cell provided in some embodiments of the present application;

[0055] Fig. 22 A partial cross-sectional schematic diagram of a battery cell provided in some embodiments of the present application;

[0056] Fig.23 A partial cross-sectional schematic diagram of a battery cell provided in some embodiments of the present application;

[0057] Fig.24 A flow chart for preparing an electrode assembly provided for some embodiments of the present application.

[0058] The reference numerals in the specific implementation manner are as follows:

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

[0060] The first direction is Z, the second direction is X, the third direction is Y, and the axial direction of the pole is R.

[0061] Battery cell 10, box 20, first box 201, second box 202,

[0062] Shell 11, shell body 111, opening 1110, shell cover 112, mounting hole 113,

[0063] Pole 12, accommodating portion 121, first accommodating groove 12110, first end wall 12111, first sinking groove 12112, first side wall 12113, second accommodating groove 12120, second end wall 12121, second sinking groove 12122, second side wall 12123, through hole 12130, pole inner end surface 122, pole outer end surface 123, first groove 126, spacer 127, cover plate 13; first conductive member 131; second groove 1311; second conductive member 132;

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

[0065] Bracket 3, through hole 314, insulating member 4, explosion-proof valve 6, slot cover 7,

[0066] A first ultrasonic welding seat 81 , a first ultrasonic welding head 82 , a second ultrasonic welding seat 91 , and a second ultrasonic welding head 92 . DETAILED DESCRIPTION

[0067] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0068] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0069] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0070] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0071] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0072] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0073] In the description of the embodiments of the present application, the orientations or positional relationships indicated by technical terms such as "center", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", and "circumferential" are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the embodiments of the present application and simplifying the description. They do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0074] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0075] At present, from the perspective of market development, the application of power batteries is becoming more and more extensive. Power batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars, as well as military equipment and aerospace and other fields. With the continuous expansion of the application field of power batteries, the market demand is also constantly expanding.

[0076] In the related art, the electrode assembly of the battery cell includes a plurality of stacked layers of pole tab sheets, which are connected to form a pole tab portion by ultrasonic welding. However, due to the influence of processing and tolerance, the stacked layers of pole tab sheets cannot be completely overlapped, resulting in misalignment problems.

[0077] Generally speaking, during the assembly process of a battery cell, the pole ear needs to be passed through the through-hole structure first, and then the pole ear needs to be welded to the pole. The through-hole structure here can be a through-hole structure on the pole, or a through-hole structure on a bracket located between the pole and the electrode assembly. The misplaced pole ear is relatively fluffy, and in the process of passing through the through-hole structure, it is easy to interfere with the hole wall of the through-hole structure, which not only affects the assembly efficiency of the battery cell, but also easily scratches the pole ear sheet. Therefore, before welding the pole ear to the pole, it is necessary to first cut the pole ear to cut off the misplaced part, and then press the welding nozzle to the welding position of the pole ear, otherwise the welding nozzle will be pressed into the fluffy area of ​​the pole ear, which will cause welding defects.

[0078] In addition, since the misaligned part needs to be cut off before the pole ear is connected to the pole post, the overall length of the pole ear becomes shorter and the utilization rate is reduced. When the pole ear is welded to the pole post, the required welding nozzle is smaller, the weld mark length formed by the welding of the pole ear and the pole is smaller, the flow area is smaller, and the flow efficiency is lower, which affects the charging and discharging efficiency of the battery cell and causes the capacity of the battery cell to be reduced.

[0079] To this end, an embodiment of the present application proposes an electrode assembly, in which the overlapping areas of multiple pole lugs are welded to form a first welding portion, and the offset areas of multiple pole lugs are welded away from the position of the active material coating portion to form a second welding portion, so that the area of ​​the welding region of the multiple pole lugs can be increased. On the one hand, the utilization rate of the pole lug portion is improved, which is beneficial to improve the capacity of the battery cell and reduce the over-current temperature rise. On the other hand, when the pole lug portion is welded to the pole column, the second welding portion can better support the welding nozzle than the fluffy multiple pole lug sheets, thereby reducing the problem of welding defects caused by the welding nozzle in the related technology being pressed onto the fluffy area of ​​the multiple pole lug sheets, reducing the cutting requirements for the pole lug portion after welding, saving costs, and improving the fast charging performance of the battery cell.

[0080] The electrode assembly disclosed in the embodiment of the present application is used for a battery cell, and the battery cell can be used in an electrical device that uses a battery as a power source or various energy storage systems that use a battery as an energy storage element. The electrical device can be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, and the like. Among them, the electric toy can include a fixed or mobile electric toy, for example, a game console, an electric car toy, an electric ship toy, and an electric airplane toy, and the like, and the spacecraft can include an airplane, a rocket, a space shuttle, and a spacecraft, and the like.

[0081] For the convenience of description, the following embodiments are described by taking an electric device 1000 of an embodiment of the present application as a vehicle as an example.

[0082] Please refer to Figure 1 , Figure 1 A schematic diagram of the structure of a vehicle provided for some embodiments of the present application. The vehicle may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle, and the battery 100 may be provided at the bottom, head or tail of the vehicle. The battery 100 may be used to power the vehicle, for example, the battery 100 may be used as an operating power source for the vehicle. The vehicle may also include a controller 200 and a motor 300, and the controller 200 is used to control the battery 100 to power the motor 300, for example, for starting, navigating and driving the vehicle.

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

[0084] Please refer to Figure 2 , Figure 2 An exploded view of a battery 100 provided in some embodiments of the present application. The battery 100 includes a box 20 and a battery cell 10, and the battery cell 10 is contained in the box 20. Among them, the box 20 is used to provide a storage space for the battery cell 10, and the box 20 can adopt a variety of structures. In some embodiments, the box 20 may include a first box 201 and a second box 202, and the first box 201 and the second box 202 cover each other, and the first box 201 and the second box 202 jointly define a storage space for accommodating the battery cell 10. The second box 202 may be a hollow structure with an opening 1110 at one end, and the first box 201 may be a plate-like structure, and the first box 201 covers the open side of the second box 202, so that the first box 201 and the second box 202 jointly define a storage space; the first box 201 and the second box 202 may also be hollow structures with one side open, and the open side of the first box 201 covers the open side of the second box 202. Of course, the box body 20 formed by the first box body 201 and the second box body 202 can be in various shapes, such as a cylinder, a cuboid, etc.

[0085] In the battery 100, there may be multiple battery cells 10, and the multiple battery cells 10 may be connected in series, in parallel, or in a mixed connection. A mixed connection means that the multiple battery cells 10 are both connected in series and in parallel. The multiple battery cells 10 may be directly connected in series, in parallel, or in a mixed connection, and then the whole formed by the multiple battery cells 10 is accommodated in the box 20; of course, the battery 100 may also be a battery 100 module formed by connecting multiple battery cells 10 in series, in parallel, or in a mixed connection, and then the multiple battery 100 modules are connected in series, in parallel, or in a mixed connection to form a whole, and accommodated in the box 20. The battery 100 may also include other structures, for example, the battery 100 may also include a busbar component for realizing electrical connection between the multiple battery cells 10.

[0086] Each battery cell 10 may be a secondary battery or a primary battery, or a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 10 may be cylindrical, flat, rectangular, or in other shapes.

[0087] Please refer to Figure 3 and Figure 4 , Figure 3 A three-dimensional diagram of a battery cell 10 provided in some embodiments of the present application; Figure 4The structure of the battery cell 10 provided in some embodiments of the present application is a cross-sectional view. The battery cell 10 refers to the smallest unit constituting the battery 100. Figure 3 and Figure 4 The battery cell 10 includes a shell 11 and an electrode assembly 2 , and the shell 11 includes a shell cover 112 and a shell body 111 .

[0088] The shell body 111 has an opening 1110, and the shell cover 112 refers to a component that covers the opening 1110 to isolate the internal environment of the battery cell 10 from the external environment. Without limitation, the shape of the shell cover 112 can be adapted to the shape of the shell body 111 to match the shell body 111. Optionally, the shell cover 112 can be made of a material with a certain hardness and strength (such as an aluminum alloy), so that the shell cover 112 is not easy to deform when it is squeezed and collided, so that the battery cell 10 can have a higher structural strength and reliability can also be improved. Functional components such as electrode terminals can be provided on the shell cover 112. The electrode terminal can be used to electrically connect to the electrode assembly 2 for outputting or inputting electrical energy of the battery cell 10. In some embodiments, the shell cover 112 can also be provided with a pressure relief mechanism for releasing the internal pressure when the internal pressure or temperature of the battery cell 10 reaches a threshold. The material of the shell cover 112 can also be a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiment of the present application does not impose any special restrictions on this. In some embodiments, an insulating member may be provided inside the housing cover 112 to isolate the electrical connection components in the housing body 111 from the housing cover 112 to reduce the risk of short circuit. For example, the insulating member may be plastic, rubber, or the like.

[0089] The shell body 111 is a component used to cooperate with the shell cover 112 to form the internal environment of the battery cell 10, wherein the formed internal environment can be used to accommodate the electrode assembly 2, the electrolyte and other components. The shell body 111 and the shell cover 112 can be independent components, and an opening 1110 can be set on the shell body 111, and the shell cover 112 is made to cover the opening 1110 at the opening 1110 to form the internal environment of the battery cell 10. Without limitation, the shell cover 112 and the shell body 111 can also be integrated. Specifically, the shell cover 112 and the shell body 111 can form a common connection surface before other components are put into the shell, and when it is necessary to encapsulate the interior of the shell body 111, the shell cover 112 is made to cover the shell body 111. The shell body 111 can be of various shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism, etc. Specifically, the shape of the shell body 111 can be determined according to the specific shape and size of the electrode assembly 2. The shell 111 may be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiment of the present application does not impose any special limitation on this.

[0090] The shell 111 may contain one or more electrode assemblies 2. The electrode assembly 2 is a component in the battery cell 10 where electrochemical reactions occur. The electrode assembly 2 includes an active material coating portion 21 and a pole ear portion 22, and the pole ear portion 22 is connected to the active material coating portion 21. The electrode assembly 2 is mainly formed by winding or stacking a positive electrode sheet and a negative electrode sheet, and a separator is usually provided between the positive electrode sheet and the negative electrode sheet. The portion of the positive electrode sheet and the negative electrode sheet with active material constitutes the active material coating portion 21 of the electrode assembly 2, and the portion of the positive electrode sheet and the negative electrode sheet without active material each constitutes the pole ear portion 22. During the charge and discharge process of the battery 100, the positive electrode active material and the negative electrode active material react with the electrolyte, and the pole ear portion 22 connects the electrode terminal to form a current loop.

[0091] The electrode assembly 2 is a component in the battery cell 10 where electrochemical reactions occur. One or more electrode assemblies 2 may be contained in the housing 11. The electrode assembly 2 includes an active material coating portion 21 and a pole ear portion 22 connected to the active material coating portion 21. Specifically, the electrode assembly 2 is mainly formed by winding or stacking a positive electrode sheet, a separator, and a negative electrode sheet. The portions of the positive electrode sheet and the negative electrode sheet with active materials constitute the active material coating portion 21 of the electrode assembly 2, and the portions of the positive electrode sheet and the negative electrode sheet without active materials each constitute the pole ear portion 22. The positive pole ear portion and the negative pole ear portion may be located together at one end of the active material coating portion 21 or at both ends of the active material coating portion 21, respectively. During the charge and discharge process of the battery 100, the positive electrode active material and the negative electrode active material react with the electrolyte, and the pole ear portion 22 connects the electrode terminal (e.g., pole post) to form a current loop.

[0092] like Figure 3 and Figure 4 The battery cell 10 also includes a bracket 3, an insulating member 4 and an explosion-proof valve 6. The bracket 3 is arranged at one end of the active material coating portion 21. The bracket 3 is provided with a through hole 314. The pole ear portion 22 passes through the through hole 314 to connect with the pole 12. The insulating member 4 is connected to the bracket 3 and wrapped together in the circumference of the electrode assembly 2. The insulating member 4 can be used to isolate the electrical connection components in the shell 11 from the shell 11 to reduce the risk of short circuit. Exemplarily, the insulating member 4 can be plastic, rubber, etc. Among them, the insulating member 4 and the bracket 3 can be connected by bonding or hot melt. Of course, the insulating member 4 and the bracket 3 can also be connected in other ways. The explosion-proof valve 6 is arranged on the shell 11, and the explosion-proof valve 6 is used to release the internal pressure when the internal pressure or temperature of the battery cell 10 reaches a threshold. Among them, the explosion-proof valve 6 can be arranged on the shell cover 112, or on any wall of the shell body 111.

[0093] According to some embodiments of this application, please continue to refer to Figure 4 , and further refer to Figure 5 , Figure 5A partial enlarged view of the electrode assembly 2 provided for some embodiments of the present application. The pole ear portion 22 of the electrode assembly 2 includes a plurality of pole ear sheets 221 stacked. Affected by factors such as the manufacturing method and manufacturing tolerance, it is difficult to strictly align the multi-layer pole ear sheets 221 after being stacked, and there is a phenomenon of edge misalignment. Therefore, on the projection plane perpendicular to the thickness direction of the pole ear sheet 221, the area where the projections of the multi-layer pole ear sheets 221 completely overlap is set as the overlapping area Z1, and the area where the projections of the multi-layer pole ear sheets 221 do not completely overlap is set as the misalignment area Z2, that is, the plurality of pole ear sheets 221 have overlapping areas Z1 and misalignment areas Z2 after being stacked. Among them, the reason for the appearance of the misalignment area Z2 is that the electrode assembly 2 is formed by winding or laminating the positive electrode sheet and the diaphragm negative electrode sheet. When the electrode assembly 2 is in the process of winding or laminating, due to production errors, the pole ear sheets 211 corresponding to each layer of the positive electrode sheet or the negative electrode sheet cannot be completely aligned.

[0094] Please refer to further Figure 6 and Figure 7 , Figure 6 A side view of an electrode assembly 2 provided in some embodiments of the present application; Figure 7 for Figure 6 The overlapping region Z1 is welded to form a first welding portion 2211, thereby welding the plurality of pole tabs 221 together at the overlapping region Z1, and the dislocation region Z2 is welded to form a second welding portion 2212 at least at a position away from the active material coating portion 21, thereby welding the plurality of pole tabs 221 together at a position away from the active material coating portion 21 in the dislocation region Z2.

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

[0096] Generally speaking, before welding the pole ear 22 to the pole 12, the pole ear 22 needs to be cut first, and then the welding nozzle is pressed into the welding position of the pole ear 22. Otherwise, the welding nozzle is pressed into the fluffy area of ​​the pole ear 22, which will cause welding defects. In addition, the fluffy pole ear 22 is not easy to pass through the through-hole structure, which affects the assembly efficiency of the battery cell 10 and is easily scratched.

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

[0098] In the technical solution of the embodiment of the present application, the overlapping area Z1 of the multiple pole lugs 221 is welded to form a first welding portion 2211, and the offset area Z2 of the multiple pole lugs 221 is welded away from the active material coating portion 21 to form a second welding portion 2212. The area of ​​the welding region of the multiple pole lugs 221 can be increased. On the one hand, the utilization rate of the pole lug portion 22 is improved, which is beneficial to improve the capacity of the battery cell 10 and reduce the over-current temperature rise. On the other hand, when the pole lug portion 22 is welded to the pole column 12, the second welding portion 2212 can better support the welding nozzle than the fluffy multiple pole lugs, and will not cause problems such as wrinkles. The problem of welding defects caused by the welding nozzle in the related technology being pressed onto the fluffy area of ​​the multiple pole lugs 221 is reduced, the cutting requirements for the pole lug portion 22 after welding are reduced, costs are saved, and the fast charging performance of the battery cell 10 is improved.

[0099] In addition, by welding the offset area Z2 to form the second welding portion 2212, the efficiency of the pole ear portion 22 passing through the through-hole structure can be improved, thereby improving the assembly efficiency of the battery cell 10 and making the pole ear portion 22 less likely to be scratched by the hole wall of the through-hole structure.

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

[0101] In the above technical scheme, compared with the fluffy multiple pole ear sheets 221, the first welding part 2211 and the second welding part 2212 are connected and arranged, on the one hand, the stiffness of the multiple pole ear sheets 221 after welding can be improved to a certain extent, so that the pole ear part 22 is not easily scratched by the hole wall of the through-hole structure, thereby improving the efficiency of the pole ear part 22 passing through the through-hole structure. On the other hand, the second welding part 2212 formed after welding is not easy to collapse under pressure relative to the first welding part 2211, and can effectively support the welding nozzle without problems such as wrinkles, which can reduce the problem of welding defects caused by the welding nozzle in the related technology being pressed onto the fluffy area of ​​the multiple pole ear sheets 221.

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

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

[0104] In the above technical scheme, by limiting the ratio range of the width dimensions of the first welding portion 2211 and the second welding portion 2212, the area of ​​the welding region of the multiple pole lugs 221 can be increased, and the utilization rate of the pole lugs 22 can be improved, which is beneficial to increasing the capacity of the battery cell 10 and reducing the over-current temperature rise. It can also reduce the problem of welding defects caused by the welding nozzle in the related technology being pressed into the fluffy area of ​​the multiple pole lugs 221.

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

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

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

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

[0109] Due to the influence of factors such as manufacturing method and manufacturing tolerance, it is difficult to strictly align the multiple layers of pole tab sheets 221 after stacking, and there is a phenomenon of edge misalignment. The height of the unaligned (misaligned) edge portion is usually small. This application needs to strictly control the height dimensions of the misaligned area Z2 and the overlapping area Z1 after the multiple pole tab sheets 221 are stacked, so that the ratio range of the height dimensions of the second welding part 2212 and the first welding part 2211 formed after welding meets the requirements.

[0110] In the above technical scheme, by limiting the ratio range of the height dimensions of the first welding portion 2211 and the second welding portion 2212, the height dimension of the first welding portion 2211 is as large as possible and the height dimension of the second welding portion 2212 is as small as possible, thereby improving the utilization rate of the pole ear portion 22 and reducing the cutting area of ​​the pole ear portion 22. When welding the pole ear portion 22 and the pole 12, not only can the stability of the welding press-fitting onto the pole ear portion 22 be improved, but also the welding area of ​​the pole ear portion 22 and the pole 12 can be increased, thereby increasing the welding reliability of the pole ear portion 22 and the pole 12.

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

[0112] In the above technical solution, by limiting the ratio range of the height dimensions of the first welding portion 2211 and the pole ear portion 22, the area of ​​the first welding portion 2211 is increased, the utilization rate of the pole ear portion 22 can be improved, and the cutting area of ​​the pole ear portion 22 can be reduced, which is beneficial to reducing the over-current temperature rise and improving the charging and discharging efficiency of the battery cell 10, thereby increasing the capacity of the battery cell 10.

[0113] Please refer again Figure 5-Figure 7, along the height direction of the pole ear portion 22, the height dimension of the second welding portion 2212 is 1 mm-2 mm. For example, the height dimension h2 of the second welding portion 2212 can be 1 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm or 2 mm.

[0114] In the above technical scheme, by limiting the height dimension of the second welding portion 2212 to meet the above conditions, on the one hand, the proportion of the misaligned area Z2 of the multiple pole tabs 221 can be reduced as much as possible, the cutting area of ​​the pole tab portion 22 can be reduced, and the qualified rate of the electrode assembly 2 can be improved, which is beneficial to improving the quality of the battery cell 10. On the other hand, based on the fact that the multiple pole tabs 221 are misaligned, the misaligned area Z2 is welded, which can increase the area of ​​the welding area of ​​the multiple pole tabs 221 and reduce the problem of welding defects caused by the welding nozzle in the related technology being pressed into the fluffy area of ​​the multiple pole tabs 221.

[0115] Please refer again Figure 7 Affected by factors such as manufacturing methods and manufacturing tolerances, the multi-layer pole ear sheets 221 are stacked to form an overlapping area Z1 and a dislocation area Z2. The overlapping area Z1 is welded to form a first welding portion 2211, and the dislocation area Z2 is welded to form a second welding portion 2212. The thickness of the second welding portion 2212 gradually decreases in a direction away from the first welding portion 2211. You can choose whether to cut this part as needed. When cutting is required, it is easier to cut because the thickness of the second welding portion 2212 gradually decreases.

[0116] In some embodiments, the second welding portion 2212 has a first surface 2214 and a second surface 2215 , which can be arranged relative to each other in the thickness direction of the pole ear portion 22 , and at least one of the first surface 2214 and the second surface 2215 is inclined relative to the height direction of the pole ear portion 22 .

[0117] For example, one side surface of the first welding part 2211 in the thickness direction can be set flush with the first surface 2214 in the thickness direction of the second welding part 2212, and the second surface 2215 in the thickness direction of the second welding part 2212 can be set at an angle relative to one side surface of the second welding part 2212 in the thickness direction, so that the thickness of the second welding part 2212 gradually decreases in the direction away from the first welding part 2211.

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

[0119] In the above technical solution, the second welding portion 2212 is formed in the above form, which is convenient for deciding whether to cut according to needs later, thereby improving the convenience of cutting.

[0120] Please refer again Figure 7 , the maximum distance s between the first surface 2214 and the second surface 2215 is 0.5 mm-1 mm, that is, the maximum thickness of the second welding portion 2212 is 0.5 mm-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.

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

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

[0123] That is to say, the first surface 2214 of the second welding portion 2212 formed after welding can be flush with the first welding portion 2211. When welding the pole ear portion 22 and the pole 12, a larger welding nozzle can be used so that a part of the welding nozzle can be pressed on the first welding portion 2211 and the other part can be pressed on the second welding portion 2212, that is, the first welding portion 2211 and the second welding portion 2212 can support the welding nozzle at the same time, which not only reduces the difficulty of welding, but also reduces the problem of welding defects caused by the welding nozzle being pressed onto the fluffy area of ​​multiple pole ear sheets in the related technology, reduces the cutting requirements for the pole ear portion after welding, saves costs, and improves the fast charging performance of the battery cell 10.

[0124] Therefore, in the above technical solution, the second welding portion 2212 is formed in the above form. On the one hand, it is convenient to decide whether to cut it according to the needs later, thereby improving the convenience of cutting. On the other hand, it can reduce the difficulty of welding, reduce welding defects and improve the welding quality.

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

[0126] Since the pole piece is a metal sheet with a relatively soft texture, the first surface 2214 and the second surface 2215 are not completely flat, and wrinkles may be caused during the production or processing process. Therefore, the above angles are approximate ranges and do not affect the protection of other values ​​within the error range.

[0127] Please refer to Figure 8-Figure 11 , Figure 8 A schematic diagram of the structure of the pole ear portion 22 of the electrode assembly 2 provided in some embodiments of the present application before pairing; Fig. 9 A schematic diagram of the structure of the electrode ear portion 22 of the electrode assembly 2 provided in some embodiments of the present application after being matched with the first ultrasonic welding seat 81 and the first ultrasonic welding head 82; Fig.10 A schematic diagram of the structure of the overlapping area Z1 of the pole ear portion 22 of the electrode assembly 2 provided in some embodiments of the present application before welding with the first ultrasonic welding seat 81 and the first ultrasonic welding head 82; Fig.11 This is a schematic diagram of the structure of the electrode assembly 2 provided in some embodiments of the present application, wherein the overlapping area Z1 of the pole ear portion 22 is ultrasonically welded to form a first welding portion 2211. The first welding portion 2211 is formed by ultrasonic welding.

[0128] Specifically, after the multiple pole tabs 221 are paired, the multiple pole tabs 221 are stacked, and the stacked multiple pole tabs 221 have an overlapping area Z1 and a misaligned area Z2. The overlapping area Z1 is clamped between the first ultrasonic welding seat 81 and the first ultrasonic welding head 82, and friction is generated between any two adjacent pole tabs 221 to cause melting, so that the multiple pole tabs 221 are welded together in the overlapping area Z1, thereby forming a first welding portion 2211.

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

[0130] Please refer to Figure 12-14 , Fig.12A schematic diagram of the structure of the misaligned area Z2 of the pole ear portion 22 of the electrode assembly 2 provided in some embodiments of the present application before welding with the second ultrasonic welding seat 91 and the second ultrasonic welding head 92; Fig.13 A schematic diagram of the structure of an electrode assembly 2 provided in some embodiments of the present application, wherein a dislocation region Z2 of the electrode ear portion 22 away from the active material coating portion 21 is ultrasonically welded to form a second welding portion 2212; Fig.14 This is a schematic diagram of the structure of the electrode assembly 2 provided in some embodiments of the present application. The second welding portion 2212 is formed by ultrasonic welding.

[0131] Specifically, the position of the dislocation region Z2 away from the active material coating portion 21 is clamped between the second ultrasonic welding seat 91 and the second ultrasonic welding head 92, and friction is generated between any two adjacent pole tabs 221 to melt, thereby welding the multiple pole tabs 221 together at the position of the dislocation region Z2 away from the active material coating portion 21, thereby forming a second welding portion 2212.

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

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

[0134] Specifically, the end misalignment area Z21 of the stacked multi-layer pole ear sheet 221 will have an adverse effect on the subsequent assembly of the pole ear portion 22 and the laser welding of the pole ear portion 22 and the pole post 12. Therefore, in the related art, it is necessary to use a cutter to cut off all the end misalignment areas Z21 of the multi-layer pole ear sheet 221 during the production process of the electrode assembly 2, so that the multi-layer pole ear sheet 221 only retains the overlapping area Z1 without misalignment. After cutting, the multi-layer pole ear sheet 221 in the remaining overlapping area Z1 is ultrasonically pre-welded to form the pole ear portion 22, and then the pole ear portion 22 is laser welded to the pole post 12. However, in the process of cutting the pole ear 221, in order to improve the cutting quality, it is necessary to adjust the position of the cutter in real time, and when the relative positions of multiple pole ear portions 22 on electrode assemblies 2 of different specifications are different, it is also necessary to adjust the position of the cutter for simultaneously cutting multiple pole ear portions 22 on electrode assemblies 2 of different specifications. Therefore, the processing efficiency is low, and the length of the pole ear portion 22 after cutting is shortened, and the weld mark area after welding with the pole column 12 is smaller, the current capacity is reduced, which affects the charging and discharging efficiency of the battery cell 10, and there is a problem of material waste of the pole ear 221.

[0135] In the embodiment of the present application, the end misalignment area Z21 of the multi-layered pole tab sheet 221 is bent, stacked and connected to realize the reuse of the end misalignment area Z21, and improve the adverse effects of the end misalignment area Z21 of the multi-layered pole tab sheet 221 on the subsequent assembly of the pole tab 22 (for example, passing the pole tab 22 through the perforation on the pole post 12) and the subsequent welding of the pole tab 22 with the pole post 12 or the adapter. Moreover, compared with cutting off the end misalignment area Z21 completely, it is equivalent to increasing the ultrasonic pre-welding area of ​​the pole tab 22, thereby increasing the area of ​​electrical connection between the pole tab 22 and the pole post 12, which is conducive to improving the current capacity and the charging and discharging efficiency of the battery cell 10. Furthermore, since there is no need to use a cutter to cut the end misaligned area Z21 of the pole ear portion 22, the time for adjusting the cutter in the cutting process is saved, and the multiple pole ear portions 22 of the electrode assembly 2 do not need to be cut synchronously and the process of adjusting the cutter is introduced, which is conducive to speeding up the production cycle of the electrode assembly 2 and improving the production efficiency of the electrode assembly 2. In addition, since the end misaligned area Z21 of the multi-layer pole ear sheet 221 is reused, material waste is reduced and the material utilization rate of the pole ear portion 22 is improved.

[0136] Please refer to Fig.15 and Fig.16 , Fig.15 A partial enlarged view of the electrode assembly 2 provided in some other embodiments of the present application; Fig.16A top view of an electrode assembly 2 provided in some other embodiments of the present application. In some other embodiments, the dislocation 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 dislocation region Z2 after the plurality of tab sheets 221 are stacked includes two side dislocation regions Z22, the two side dislocation regions Z22 are located on both sides of the overlapping region Z1 in the width direction, and at least one side dislocation region Z22 is welded to form a third weld 2213.

[0137] In the above technical scheme, by welding the misaligned area Z2 on at least one side of the overlapping area Z1 to form a third welding portion 2213, on the one hand, the area of ​​the welding area of ​​the multiple pole lugs 221 can be increased, thereby improving the utilization rate of the pole lug portion 22, which is beneficial to increasing the capacity of the battery cell 10 and reducing the over-current temperature rise; on the other hand, it can reduce the problem of welding defects caused by the welding nozzle in the related technology being pressed onto the fluffy area of ​​the multiple pole lugs 221, and can also facilitate the pole lug portion 22 to pass through the through-hole on the pole column 12.

[0138] Please refer to Fig.17 , Fig.17 A schematic cross-sectional view of the pole ear portion 22 of the electrode assembly 2 provided in some other embodiments of the present application. In some other embodiments, a first portion of at least one side offset zone Z22 is bent toward the remaining second portion of the side offset zone Z22 in a direction close to the active material coating portion 21, and then stacked and welded together to form a third welding portion 2213.

[0139] Specifically, the side misalignment area Z22 of the stacked multi-layer pole ear sheet 221 will have an adverse effect on the subsequent assembly of the pole ear portion 22 and the laser welding of the pole ear portion 22 and the pole post 12. Therefore, in the related art, it is necessary to use a cutter to cut off all the side misalignment areas Z22 of the multi-layer pole ear sheet 221 during the production process of the electrode assembly 2, so that the multi-layer pole ear sheet 221 only retains the overlapping area Z1 without misalignment. After cutting, the multi-layer pole ear sheet 221 in the remaining overlapping area Z1 is ultrasonically pre-welded to form the pole ear portion 22, and then the pole ear portion 22 is laser welded to the pole post 12. However, in the process of cutting the pole ear 221, in order to improve the cutting quality, it is necessary to adjust the position of the cutter in real time, and when the relative positions of multiple pole ear portions 22 on electrode assemblies 2 of different specifications are different, it is also necessary to adjust the position of the cutter for simultaneously cutting multiple pole ear portions 22 on electrode assemblies 2 of different specifications. Therefore, the processing efficiency is low, and the length of the pole ear portion 22 after cutting is shortened, and the weld mark area after welding with the pole column 12 is smaller, the current capacity is reduced, which affects the charging and discharging efficiency of the battery cell 10, and there is a problem of material waste of the pole ear 221.

[0140] In the embodiment of the present application, the side misalignment area Z22 of the multi-layered pole tab sheet 221 is bent, stacked and connected to realize the reuse of the side misalignment area Z22, and improve the adverse effects of the side misalignment area Z22 of the multi-layered pole tab sheet 221 on the subsequent assembly of the pole tab 22 (for example, passing the pole tab 22 through the perforation on the pole post 12) and the subsequent welding of the pole tab 22 with the pole post 12 or the adapter sheet. Moreover, compared with cutting off all the side misalignment area Z22, it is equivalent to increasing the ultrasonic pre-welding area of ​​the pole tab 22, thereby increasing the area of ​​electrical connection between the pole tab 22 and the pole post 12, which is conducive to improving the current capacity and the charging and discharging efficiency of the battery cell 10. Furthermore, since there is no need to use a cutter to cut the side offset zone Z22 of the pole ear portion 22, the time for adjusting the cutter in the cutting process is saved, and the multiple pole ear portions 22 of the electrode assembly 2 do not need to be cut synchronously and the process of adjusting the cutter is introduced, which is conducive to speeding up the production cycle of the electrode assembly 2 and improving the production efficiency of the electrode assembly 2. In addition, since the side offset zone Z22 of the multi-layer pole ear sheet 221 is reused, material waste is reduced and the material utilization rate of the pole ear portion 22 is improved.

[0141] To sum up, the misaligned area Z2 of the multi-layer pole ear sheet 221 is reused by stacking and connecting them after bending, which solves the adverse effects of the misaligned area Z2 of the multi-layer pole ear sheet 221 on subsequent processes, and at the same time expands the electrical connection area between the pole ear portion 22 and the pole 12, improves the current carrying capacity, and eliminates the process and time of adjusting the cutter position in real time, which is beneficial to improving the processing efficiency of the electrode assembly 2, meeting the beat requirements of the high-speed mass production line, and is beneficial to reducing material waste and improving the material utilization rate of the pole ear sheet 221.

[0142] Please refer again Figure 3 and Figure 4 According to some embodiments of the present application, the present application provides a battery cell 10. The battery cell 10 includes a shell 11 and an electrode assembly 2. The shell 11 is provided with a pole 12. The electrode assembly 2 is arranged in the shell 11. The pole ear 22 is connected to the pole 12. The electrode assembly 2 is the electrode assembly 2 of any of the above embodiments.

[0143] In the technical solution of the embodiment of the present application, by adopting the above-mentioned electrode assembly 2, on the one hand, the utilization rate of the pole ear portion 22 is improved, which is beneficial to improving the capacity of the battery cell 10 and reducing the overcurrent temperature rise. On the other hand, when welding the pole ear portion 22 to the pole 12, the second welding portion 2212 can better support the welding nozzle than the fluffy multiple pole ear sheets, and will not cause problems such as wrinkles, thereby reducing the problem of welding defects caused by the welding nozzle in the related technology being pressed onto the fluffy area of ​​the multiple pole ear sheets 221, thereby improving the reliability of the battery cell 10 and reducing the cutting requirements for the pole ear portion 22 after welding, thereby reducing the production difficulty of the battery cell 10, saving costs, and improving the fast charging performance of the battery cell 10.

[0144] Please refer to Fig.12 and Fig.13 , Fig.12 A partial cross-sectional schematic diagram of a battery cell 10 provided in some embodiments of the present application. Fig.13 The partial cross-sectional schematic diagram of the battery cell 10 provided in some embodiments of the present application. The pole 12 is provided with a receiving portion 121, and at least a portion of the pole ear portion 22 is extended into and received in the receiving portion 121, and the pole ear portion 22 is electrically connected to the pole 12. That is, the pole 12 is set as a hollow structure.

[0145] Among them, at least partially means that the pole ear portion 22 can be completely accommodated in the accommodating portion 121, or a part of the pole ear portion 22 can be accommodated in the accommodating portion 121. Since the pole 12 is provided with the accommodating portion 121, the hollow structure of the accommodating portion 121 can reduce the weight of the pole 12 to a certain extent, so as to improve the weight energy density of the battery cell 10 and the battery 100. On the other hand, the pole ear portion 22 can be accommodated in the accommodating portion 121, which improves the assembly efficiency of the pole ear portion 22, and can also save the space occupied by the pole ear portion 22, making full use of the space of the battery cell 10, so that the cooperation between the bracket 3 and the pole 12, and between the bracket 3 and the pole ear portion 22 are tighter and more reliable, making the structure of the battery cell 10 more compact, and more conducive to the improvement of the energy density of the battery cell 10.

[0146] More specifically, the pole ear portion 22 is partially or completely accommodated in the accommodation portion 121, so that the portion of the pole ear portion 22 located in the accommodation portion 121 can occupy the space in the pole column 12, which can reduce the space occupied by the pole ear portion 22 in the shell 11. When the size of the shell 11 is fixed, some space can be saved in the shell 11 to accommodate a larger active material coating portion 21, thereby improving the volume energy density of the battery cell 10. For example, when the pole ear portion 22 is led out from the side of the active material coating portion 21 close to the pole column 12, the space occupied by the pole ear portion 22 between the active material coating portion 21 and the pole column 12 can be saved, the size of the active material coating portion 21 in the direction of leading out the pole ear portion 22 can be increased, the distance between the active material coating portion 21 and the pole column 12 can be reduced, and the energy density of the battery cell 10 can be improved.

[0147] At the same time, by accommodating at least part of the pole ear portion 22 in the accommodating portion 121, the space occupied by the battery cell 10 itself can be reduced, so that the battery 100 of the same volume can accommodate a larger number of battery cells 10, and the volume energy density of the battery 100 can be improved; in addition, accommodating at least part of the pole ear portion 22 in the accommodating portion 121 to occupy the space in the pole column 12 can reduce the redundancy of the pole ear portion 22 in the shell 11 to at least a certain extent, reduce the probability of short circuit between the pole ear portion 22 and the active material coating portion 21, reduce the probability of short circuit of the battery cell 10, and improve the working reliability and stability of the battery cell 10 and the battery 100.

[0148] It should be noted that, in the embodiment of the present application, the accommodation portion 121 may be located on the side of the pole 12 facing the active material coating portion 21 or on the side of the pole 12 away from the active material coating portion 21 .

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

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

[0151] In the above technical solution, on the one hand, the first receiving groove 12110 is provided on the pole 12 to reduce the weight of the pole 12 to a certain extent, so as to improve the weight energy density of the battery cell 10 and the battery 100; on the other hand, since the notch of the first receiving groove 12110 is formed on the inner end surface 122 of the pole, and the inner end surface 122 of the pole is the surface of the pole 12 close to the active material coating part 21, the first receiving groove 12110 can be opened toward the active material coating part 21, thereby facilitating the extension of the pole ear part 22 into the first receiving groove 12110, thereby improving the assembly efficiency. Moreover, this type of first receiving groove 12110 is easy to process, thereby improving the production efficiency.

[0152] Furthermore, the first receiving groove 12110 can be easily processed to have a larger volume, so as to accommodate more pole ear portions 22; at the same time, since the first receiving groove 12110 is open toward the direction of the active material coating portion 21, the first receiving groove 12110 can also be used as a buffer and temporary storage structure for the electrolyte, so that more electrolyte can be accommodated in the shell 11. Since the battery cell 10 consumes electrolyte during the charging and discharging process, when there is more electrolyte, the service life of the battery cell 10 can be extended; and also because the first receiving groove 12110 is open toward the direction of the active material coating portion 21, the first receiving groove 12110 can also be used as a receiving and buffer structure for gas production inside the electrode assembly 2, thereby reducing the expansion of the battery cell 10 and improving the reliability and stability of the battery cell 10.

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

[0154] Please refer again Fig.12In the embodiment of the present application, the connection method between the pole 12 and the housing 11 is not limited, for example, it can be welding or riveting. For example, when the two are matched by riveting, the housing 11 has a mounting hole 113, and the pole 12 is riveted and installed at the mounting hole 113. Of course, it is understandable that when the two are matched by welding or other methods, the housing 11 can also be provided with a mounting hole 113 to facilitate the pole 12 to be installed on the housing 11 through the mounting hole 113, which is not limited here.

[0155] At the same time, the first receiving groove 12110 can be arranged corresponding to the position of the mounting hole 113, or in other words, on the projection plane perpendicular to the axial direction R of the pole 12, the orthographic projection of the first receiving groove 12110 is located within the orthographic projection range of the mounting hole 113, so that the first receiving groove 12110 can have a greater depth to accommodate more pole ear parts 22, thereby further reducing the space occupied by the pole ear parts 22 in the housing 11. Specifically, when the housing 11 is provided with a mounting hole 113 and the pole 12 is mounted in the mounting hole 113, along the axial direction R of the pole 12, the depth H1 of the first receiving groove 12110 is greater than or equal to the minimum distance H2 from the inner end face 122 of the pole to the mounting hole 113.

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

[0157] Since in the axial direction R of the pole 12, the depth H1 of the first receiving groove 12110 is greater than or equal to the minimum distance H2 from the inner end face 122 of the pole to the mounting hole 113, the volume of the pole 12 can be fully utilized, so that the first receiving groove 12110 has a larger depth, which is conducive to accommodating more pole ears 22, thereby further reducing the space occupied by the pole ears 22 in the shell 11 to a greater extent, further improving the energy density of the battery cell 10, and further reducing the redundancy of the pole ears 22 in the shell 11; at the same time, since the first receiving groove 12110 has a larger depth, it can also accommodate the gas production of the electrode assembly 2, improve the reliability and stability of the battery cell 10, and can also accommodate more electrolyte to increase the service life of the battery cell 10.

[0158] Please refer again Fig.12 and Fig.13In order to improve the stability and reliability of the electrical connection between the active material coating portion 21 and the pole 12, in some embodiments of the present application, the electrical connection position between the pole ear portion 22 and the pole 12 can be located on the groove wall of the first accommodating groove 12110 formed by the accommodating portion 121.

[0159] Exemplarily, the pole ear 22 and the pole 12 can be electrically connected by welding, and the electrical connection position is the welding position of the pole ear 22 and the pole 12. At the same time, the welding method of the pole ear 22 and the pole 12 is not limited, for example, it can be laser welding, and according to factors such as the position, angle, or structure of the welding part, vertical welding, inclined welding, lap welding, edge sealing welding, etc. can be selected. In other embodiments of the present application, the pole ear 22 and the pole 12 can also be electrically connected by other methods instead of welding, such as by providing conductive glue or conductive nails. To simplify the description, the following text takes the example of the pole ear 22 and the pole 12 being welded to form an electrical connection, and the welding position is the electrical connection position of the pole ear 22 and the pole 12.

[0160] Specifically, the pole 12 specifically includes a first end wall 12111 and a first side wall 12113, the first end wall 12111 is located on a side of the first side wall 12113 away from the active material coating portion 21, the first end wall 12111 and the first side wall 12113 are surrounded to form a first receiving groove 12110, and the electrical connection position of the pole ear portion 22 and the pole 12 is located at the first end wall 12111 and / or the first side wall 12113. In other words, the pole ear portion 22 may be welded to at least one of the first end wall 12111 and the first side wall 12113.

[0161] In the above technical solution, by setting the electrical connection position between the pole ear portion 22 and the pole 12 on at least one of the first end wall 12111 and the first side wall 12113, the first receiving groove 12110 not only has the function of accommodating at least part of the pole ear portion 22, but also the groove wall of the first receiving groove 12110 has the function of realizing electrical connection with the pole ear portion 22, which can simplify the structure of the pole 12, facilitate the processing of the pole 12, and simplify the structure of the pole ear portion 22, reduce the redundancy of the pole ear portion 22, and reduce the cost of the pole ear portion 22. Moreover, by using the groove wall of the first receiving groove 12110 to realize the electrical connection with the pole ear portion 22, the area where the pole ear portion 22 is electrically connected to the pole 12 can be set relatively large, which can not only reduce the difficulty of electrical connection, but also improve the reliability and stability of electrical connection, thereby improving the performance of the battery cell 10.

[0162] In addition, since the electrical connection position between the pole ear portion 22 and the pole 12 is located in the first receiving groove 12110, not only can the electrical connection position be reduced from protruding outside the pole 12 and occupying space outside the pole 12, but the electrical connection position can also be protected by the pole 12, thereby improving the reliability and stability of the electrical connection between the pole ear portion 22 and the pole 12.

[0163] In addition, in an embodiment of the present application, the first end wall 12111 is constructed as a closed structure without a through hole 12130, so that the first receiving tank 12110 is isolated from the external space of the shell 11, which can reduce the problem of electrolyte in the shell 11 leaking from the first receiving tank 12110.

[0164] Please refer again Fig.12 and Fig.13 In some optional embodiments, the partial shape of the pole ear portion 22 matches the partial shape of the first end wall 12111, and they are arranged in a close fit and electrically connected, so that the position where the pole ear portion 22 is electrically connected to the first end wall 12111 extends along the length or width direction of the first end wall 12111. For example, when the first end wall 12111 is a plane, a part of the pole ear portion 22 can also be a plane and fit to the first end wall 12111, and the fit position is electrically connected, such as by welding. In this way, the area of ​​the electrical connection can be increased, and the reliability and stability of the electrical connection can be improved.

[0165] In addition, when the electrical connection between the pole ear portion 22 and the first end wall 12111 is welding, since the first end wall 12111 is located on the side of the first receiving groove 12110 away from the active material coating portion 21, the welding operation is convenient, for example, welding can be performed from the side of the pole 12 away from the active material coating portion 21.

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

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

[0168] Please refer to Fig.14 , Fig.14A partial cross-sectional schematic diagram of a battery cell 10 provided in some embodiments of the present application. When the pole ear portion 22 is electrically connected to the first end wall 12111, a first sinking groove 12112 may be provided on the first end wall 12111, and the sinking direction of the first sinking groove 12112 is the direction away from the active material coating portion 21. At least part of the position where the pole ear portion 22 is electrically connected to the first end wall 12111 is located in the first sinking groove 12112. Exemplarily, at least part of the pole ear portion 22 may be provided in the first sinking groove 12112 and connected to the portion of the first end wall 12111 used to define the first sinking groove 12112.

[0169] In the above technical scheme, on the one hand, the first sink groove 12112 can be used to realize pre-positioning and limiting of the electrical connection position of the pole ear portion 22, which is not only conducive to finding the correct position to realize electrical connection and improve production efficiency, but also conducive to improving the stability and reliability of the pole ear portion 22, and improving the stability and reliability of the battery cell 10 during the charging and discharging process; on the other hand, by arranging the first sink groove 12112 on the first end wall 12111, the local wall thickness of the first end wall 12111 can be locally thinned, which is not only conducive to welding, but also conducive to reducing the weight of the pole 12 and improving the weight energy density of the battery cell 10.

[0170] Please refer again Fig.13 and Fig.14 In the embodiment of the present application, the pole 12 can also be provided with a first groove 126 as required, and the first groove 126 is located on the side of the pole 12 away from the active material coating portion 21, that is, the surface of the side of the pole 12 away from the active material coating portion 21 is the pole outer end face 123, and the notch of the first groove 126 is formed on the pole outer end face 123.

[0171] It can be understood that the first groove 126 is a groove body, and the groove body is a groove-shaped structure with a certain depth. In addition, when the pole 12 is arranged on the upper end wall of the shell 11, and the pole outer end face 123 is the upper surface of the pole 12, the first groove 126 is formed as a first groove 126 with a notch opening upward and a groove wall concave downward (that is, a square concave toward the electrode assembly 2). For another example, when the pole 12 is arranged on the lower end wall of the shell 11, and the pole outer end face 123 is the lower surface of the pole 12, the first groove 126 is formed as a first groove 126 with a notch opening downward and a groove wall concave upward (that is, a square concave away from the electrode assembly 2).

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

[0173] In addition, since the pole 12 has both the first receiving groove 12110 and the first groove 126, the first groove 126 is located on the side of the first receiving groove 12110 away from the active material coating portion 21, and the first groove 126 is open in the direction away from the first receiving groove 12110, which is convenient for laser welding the pole ear portion 22 and the first end wall 12111 from the outside of the pole 12, that is, the side of the pole 12 away from the active material coating portion 21, through the first groove 126, and it is convenient to realize the electrical connection between the pole ear portion 22 and the pole 12 through external welding. In other words, through the above-mentioned structural setting, it is convenient to perform external welding on the pole 12 and the pole ear portion 22 through the first groove 126, which is convenient for processing and manufacturing of the battery cell 10, and can save processing and manufacturing costs.

[0174] Furthermore, in order to conveniently and effectively weld the pole ear portion 22 to the slot wall of the first receiving slot 12110 through the first groove 126 and improve the welding reliability of the pole ear portion 22 to the slot wall of the first receiving slot 12110, in the embodiment of the present application, the portion between the first groove 126 and the first receiving slot 12110 can be laser welded to the pole ear portion 22, that is, Fig.14 The spacer 127 shown is laser welded with the pole ear portion 22 to achieve electrical connection between the electrode assembly 2 and the pole 12. The thickness of the spacer 127 of the pole 12 located between the first groove 126 and the first receiving groove 12110 is relatively thin, and the spacer 127 isolates the first groove 126 and the first receiving groove 12110. The side wall of the spacer 127 close to the active material coating portion 21 can be used as the first end wall 12111. When the pole ear portion 22 needs to be welded with the first end wall 12111, since the thickness of the spacer 127 is relatively thin, it is convenient to achieve welding of the pole ear portion 22 and the first end wall 12111 through the first groove 126, thereby improving the convenience and reliability of welding.

[0175] Please refer again Fig.13Furthermore, the battery cell 10 may also include a slot cover 7, which is provided on the pole 12 and covers the notch of the first groove 126. In the above technical solution, by providing the slot cover 7 that covers the first groove 126, the pole 12 can be indirectly electrically connected to the current collector through the slot cover 7, and the position and structure of the slot cover 7 can be set to make the electrical connection between the slot cover 7 and the current collector more convenient and the electrical connection area larger. Therefore, by providing the slot cover 7, the electrical connection between adjacent battery cells 10 in the battery 100 can be facilitated, and since the position where the battery cells 10 are electrically connected to the battery cells 10 is located at the slot cover 7, the electrical connection position with the pole ear 22 and the pole 12 can be separated by the first groove 126, and there is less interference between the two, which can further improve the stability and reliability of the battery cell 10.

[0176] For example, please refer to Fig.15 , Fig.15 A partial cross-sectional schematic diagram of a battery cell 10 provided for some embodiments of the present application, wherein the accommodating portion 121 may also be configured to include a second accommodating groove 12120, the surface of the pole 12 away from the active material coating portion 21 is the pole outer end face 123, the notch of the second accommodating groove 12120 is formed on the pole outer end face 123, the second accommodating groove 12120 is connected to the interior of the shell 11 through a through hole 12130, the pole ear portion 22 is penetrated through the through hole 12130 and is at least partially accommodated in the second accommodating groove 12120.

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

[0178] In the above technical solution, please refer to Fig.15On the one hand, the pole 12 is provided with a second receiving groove 12120, which can reduce the weight of the pole 12 to a certain extent, so as to improve the weight energy density of the battery cell 10 and the battery 100; on the other hand, since the notch of the second receiving groove 12120 is formed on the outer end surface 123 of the pole, and the outer end surface 123 of the pole is the surface of the pole 12 away from the active material coating portion 21, the second receiving groove 12120 can be opened in the direction away from the active material coating portion 21. In this way, when at least part of the pole ear portion 22 is accommodated in the second receiving groove 12120, the pole ear portion 22 can be easily stored and sorted through the notch of the second receiving groove 12120, and the electrical connection operation between the pole ear portion 22 and the pole 12 can be easily achieved through the notch of the second receiving groove 12120, thereby reducing the production difficulty of the battery cell 10 and improving the production efficiency of the battery cell 10.

[0179] At the same time, because the second receiving groove 12120 can be connected with the interior of the shell 11 through the perforation 12130, the second receiving groove 12120 can also be used as a buffer and temporary storage structure for the electrolyte, so that more electrolyte can be accommodated in the shell 11. Since the electrolyte will be consumed during the charging and discharging process of the battery cell 10, when there is more electrolyte, the service life of the battery cell 10 can be extended; and because the second receiving groove 12120 can be connected with the interior of the shell 11 through the perforation 12130, the second receiving groove 12120 can also be used as a receiving and buffer structure for gas production inside the electrode assembly 2, thereby reducing the expansion of the battery cell 10 and improving the reliability and stability of the battery cell 10.

[0180] It is worth noting that when the accommodating portion 121 has a second accommodating groove 12120, and the pole ear portion 22 is provided in the through hole 12130 and is at least partially accommodated in the second accommodating groove 12120, the electrical connection position of the pole ear portion 22 and the pole 12 is not limited. Exemplarily, when the pole ear portion 22 is provided in the through hole 12130 and is at least partially accommodated in the second accommodating groove 12120, in the embodiment of the present application, the electrical connection position of the pole ear portion 22 and the pole 12 is located at the hole wall of the through hole 12130 formed by the pole 12.

[0181] In the above technical solution, by setting the electrical connection position between the pole ear portion 22 and the pole post 12 on the hole wall of the through-hole 12130, it is convenient to perform electrical connection operation between the pole ear portion 22 and the pole post 12 through the second accommodating groove 12120, and when the electrical connection area between the pole ear portion 22 and the pole post 12 is large, the electrical connection between the pole ear portion 22 and the pole post 12 can be utilized to realize the sealing of the through-hole 12130, so as to save sealing costs, reduce electrolyte leakage, and save sealing parts.

[0182] Specifically, the pole ear portion 22 can be welded to the hole wall of the through hole 12130 at the position where the through hole 12130 is connected to the second accommodating groove 12120, which is convenient for operation. In addition, the welding mark can be controlled to seal the through hole 12130 using the welding mark and the pole ear portion 22, so as to improve the problem of electrolyte in the shell 11 leaking from the through hole 12130.

[0183] As another example, when the pole ear portion 22 is passed through the through hole 12130 and at least partially accommodated in the second accommodating groove 12120, in some other embodiments of the present application, the electrical connection position between the pole ear portion 22 and the pole 12 can also be located on the groove wall of the second accommodating groove 12120 formed by the pole 12. Thus, the electrical connection operation is facilitated. For example, when the pole ear portion 22 is welded to the groove wall of the second accommodating groove 12120 formed by the pole 12, the conductive particles generated by the welding can be prevented from entering the housing 11, causing a short circuit and other problems.

[0184] Please refer again Fig.15 The pole 12 includes a second end wall 12121 and a second side wall 12123. The second end wall 12121 is located on a side of the second side wall 12123 close to the active material coating portion 21. The second end wall 12121 and the second side wall 12123 are arranged to form a second accommodating groove 12120. The through hole 12130 is opened on the second end wall 12121. The electrical connection position between the pole ear portion 22 and the pole 12 is located on the second end wall 12121 and / or on the second side wall 12123.

[0185] More specifically, the pole ear portion 22 and the pole 12 can be electrically connected by welding, so the welding position is the electrical connection position of the pole ear portion 22 and the pole 12. In other embodiments of the present application, the pole ear portion 22 and the pole 12 can also be electrically connected by other methods instead of welding, such as providing conductive glue or conductive nails, which will not be described here.

[0186] To simplify the description, the following description takes the example that the pole ear portion 22 is welded to the pole post 12 to form an electrical connection, and the welding position is the electrical connection position of the pole ear portion 22 and the pole post 12. For example, in some embodiments, the electrical connection position of the pole ear portion 22 and the pole post 12 is located at the second end wall 12121 and / or the second side wall 12123, and the pole ear portion 22 may be welded to at least one of the second end wall 12121 and the second side wall 12123.

[0187] In the above technical solution, by setting the electrical connection position between the pole ear portion 22 and the pole 12 on at least one of the second end wall 12121 and the second side wall 12123, the second receiving groove 12120 not only has the function of accommodating at least part of the pole ear portion 22, but also the groove wall of the second receiving groove 12120 has the function of realizing electrical connection with the pole ear portion 22, which can simplify the structure of the pole 12 and facilitate the processing of the pole 12. In addition, since the through hole 12130 is provided in the second end wall 12121, it is convenient for the pole ear portion 22 to extend into the second receiving groove 12120 through the through hole 12130, which can simplify the structure of the pole ear portion 22, reduce the redundancy of the pole ear portion 22, and reduce the cost of the pole ear portion 22. Furthermore, the opening direction of the slot of the second receiving groove 12120 makes it easy to electrically connect the pole ear portion 22 with the slot wall of the second receiving groove 12120 through the slot of the second receiving groove 12120, which can reduce the difficulty of electrical connection. Moreover, by utilizing the slot wall of the second receiving groove 12120 to achieve electrical connection with the pole ear portion 22, the area where the pole ear portion 22 is electrically connected to the pole 12 can be relatively large, which can improve the reliability and stability of the electrical connection, thereby improving the performance of the battery cell 10.

[0188] In addition, since the electrical connection position between the pole ear portion 22 and the pole 12 is located in the second accommodating groove 12120, not only can the electrical connection position be reduced from protruding outside the pole 12 and occupying space outside the pole 12, but the electrical connection position can also be protected by the pole 12, thereby improving the reliability and stability of the electrical connection between the pole ear portion 22 and the pole 12.

[0189] Please refer again Fig.15 In some embodiments, the partial shape of the pole ear portion 22 matches the partial shape of the second end wall 12121, and they are arranged in a close fit and electrically connected, so that the position where the pole ear portion 22 is electrically connected to the second end wall 12121 extends along the length or width direction of the second end wall 12121. For example, when the second end wall 12121 is a plane, a part of the pole ear portion 22 can also be a plane and fit to the second end wall 12121, and the fit position is electrically connected, such as by welding. In this way, the area of ​​the electrical connection can be increased, and the reliability and stability of the electrical connection can be improved.

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

[0191] For example, please refer again to Fig.15When the second end wall 12121 is in a flat plate structure, the angle θ between the second end wall 12121 and the axial direction R of the pole 12 is equal to 90°, that is, along the direction from the through hole 12130 to the second side wall 12123, the second end wall 12121 and the active material coating portion 21 are equidistant. This facilitates welding of the pole ear portion 22 and the second end wall 12121.

[0192] For another example, the angle θ between the second end wall 12121 and the axial direction R of the pole 12 is greater than 90°, that is, along the direction from the through hole 12130 to the second side wall 12123, the second end wall 12121 extends obliquely toward the direction close to the active material coating portion 21. As a result, the extension distance of the pole ear portion 22 along the second end wall 12121 can be increased to increase the reliability of the electrical connection. Exemplarily, the angle θ between the second end wall 12121 and the axial direction R of the pole 12 can be 90°-145°, such as 100°, 110°, 120°, 130°, 140°, etc., which can make the second end wall 12121 easy to process and convenient for electrical connection with the pole ear portion 22, and can more fully utilize the space in the pole 12 to accommodate the pole ear portion 22.

[0193] For another example, the angle θ between the second end wall 12121 and the axial direction R of the pole 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 obliquely away from the active material coating portion 21 .

[0194] Thus, the extension distance of the pole ear portion 22 along the second end wall 12121 can be increased to increase the reliability of the electrical connection. Exemplarily, the angle θ between the second end wall 12121 and the axial direction R of the pole 12 can be 45°-90°, such as 50°, 60°, 70°, 80°, etc., which can make the second end wall 12121 easy to process and convenient for electrical connection with the pole ear portion 22, and can more fully utilize the space in the pole 12 to accommodate the pole ear portion 22.

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

[0196] Please refer again Fig.15 , and further refer to Fig.16 , Fig.16A partial cross-sectional schematic diagram of a battery cell 10 provided in some embodiments of the present application. Regardless of the specific value of the angle θ between the second end wall 12121 and the axial direction R of the pole 12, in the embodiments of the present application, when the pole ear portion 22 is electrically connected to the second end wall 12121, a second sinking groove 12122 can be provided on the second end wall 12121 as required, and the second sinking groove 12122 is a groove formed by a part of the second end wall 12121 sinking toward one end close to the active material coating portion 21. The position where the pole ear portion 22 is electrically connected to the second end wall 12121 is at least partially located in the second sinking groove 12122.

[0197] In the above technical solution, the portion of the pole ear 22 located in the second groove 12122 is set to match the shape of the second groove 12122, and is fitted to achieve electrical connection. The second groove 12122 can be used to pre-position and limit the electrical connection position of the pole ear 22, which is conducive to finding the correct position to achieve electrical connection, improve production efficiency, and improve the stability and reliability of the electrical connection position, so as to improve the reliability and stability of the charging and discharging operations of the battery cell 10.

[0198] Please refer again Fig.16 In the embodiment of the present application, the connection method between the pole 12 and the housing 11 is not limited, for example, it can be welding or riveting. For example, when the two are matched by riveting, the housing 11 has a mounting hole 113, and the pole 12 is riveted and installed at the mounting hole 113. Of course, it can be understood that when the two are matched by welding or other methods, the housing 11 can also be provided with a mounting hole 113, and the pole 12 is installed at the mounting hole 113.

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

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

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

[0202] Therefore, the depth H3 of the second receiving groove 12120 refers to: the maximum depth of the second receiving groove 12120 along the axial direction R of the pole 12. Since the depth H3 of the second receiving groove 12120 is greater than or equal to the minimum distance H4 from the outer end surface 123 of the pole to the mounting hole 113 in the axial direction R of the pole 12, the volume of the pole 12 can be fully utilized, so that the second receiving groove 12120 has a larger depth, which is conducive to accommodating more pole ears 22, and further can reduce the space occupied by the pole ears 22 in the shell 11 to a greater extent, further improve the energy density of the battery cell 10, and further reduce the redundancy of the pole ears 22 in the shell 11; at the same time, since the second receiving groove 12120 has a larger depth, it can also accommodate the gas generation of the electrode assembly 2, improve the reliability and stability of the battery cell 10, and can also accommodate more electrolyte to increase the service life of the battery cell 10.

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

[0204] In the above technical solution, by setting the cover plate 13 to close the notch of the second receiving groove 12120, the leakage of the electrolyte in the shell 11 from the notch of the second receiving groove 12120 can be reduced, and because the cover plate 13 closes the notch of the second receiving groove 12120 and is electrically connected to the pole 12, the cover plate 13 can be used to easily realize the indirect electrical connection between the pole 12 and the busbar component, and it is beneficial to increase the connection area of ​​the electrical connection, thereby helping to reduce the resistance of the electrical connection.

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

[0206] It should also be noted that the specific structure of the cover plate 13 is not limited. For example, in some optional embodiments, please refer to Fig.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 cooperates with and is electrically connected to the pole 12 , and the second conductive member 132 cooperates with and is electrically connected to the first conductive member 131 .

[0207] In the above technical solution, the cover plate 13 is set to a composite form, and the first conductive member 131 is set to be the same material as the pole 12, so as to facilitate the electrical connection between the first conductive member 131 and the pole 12, for example, the first conductive member 131 can be easily connected to the pole 12 reliably and stably by welding. And because the second conductive member 132 is made of a different material from the first conductive member 131, it is convenient to use the second conductive member 132 to electrically connect with a busbar component whose material is different from that of the pole 12, for example, the second conductive member 132 can be easily connected to a busbar component whose material is the same as that of the second conductive member 132 reliably and stably by welding.

[0208] For example, when the pole 12 is a negative pole 12, the pole 12 is a copper pole, and the current collecting component is an aluminum sheet, at this time, the first conductive member 131 can be set to copper material, and the second conductive member 132 can be set to aluminum material. At this time, the pole 12 and the first conductive member 131 are made of the same material and can be effectively welded, and the second conductive member 132 and the current collecting component are made of the same material and can be effectively welded, so that the pole 12 can be effectively connected to the current collecting component indirectly through the cover plate 13. Moreover, the welding of the pole 12 and the first conductive member 131 is copper material and copper material, which has good fluidity and is not easy to crack, which is conducive to improving the sealing effect of the welding point.

[0209] Please refer again Fig.17In some optional examples, the first conductive member 131 is located between the second containing groove 12120 and the second conductive member 132. In the above technical solution, since the first conductive member 131 is located between the second containing groove 12120 and the second conductive member 132, the second containing groove 12120 and the second conductive member 132 can be separated, so that when the electrolyte in the housing 11 enters the second containing groove 12120 from the through hole 12130, the first conductive member 131 can be used to prevent the part of the electrolyte from contacting the second conductive member 132, thereby solving the problem of corrosion of the second conductive member 132 by the electrolyte.

[0210] It is worth noting that the matching method of the first conductive member 131 and the second conductive member 132 is not limited. Fig.17 The first conductive member 131 has a second groove 1311, and the second conductive member 132 is embedded in the second groove 1311. The notch of the second groove 1311 is formed on the surface of the first conductive member 131 away from the second receiving groove 12120, so that the second conductive member 132 is exposed from the notch 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 also be fastening connection, clamping, etc.

[0211] It should also be noted that the “exposed” of the second conductive member 132 being exposed from the notch of the second groove 1311 means that the first conductive member 131 does not block the second conductive member 132 at the notch position of the second groove 1311, and the second conductive member 132 is not required to protrude from the notch of the second groove 1311. For example, the second conductive member 132 may be flush with the surface of the first conductive member 131 on the side away from the second accommodating 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 accommodating groove 12120.

[0212] In the above technical solution, on the one hand, by embedding the second conductive member 132 in the first conductive member 131, the difficulty of assembling the first conductive member 131 and the second conductive member 132 can be reduced, the stability and convenience of the cooperation between the first conductive member 131 and the second conductive member 132 can be improved, and the thickness of the cover plate 13 can be reduced, and the space occupied by the cover plate 13 can be reduced to improve the space utilization of the battery cell 10. On the other hand. In addition, since the second conductive member 132 can be exposed from the surface of the first conductive member 131 away from the second receiving groove 12120 through the notch of the second groove 1311, it is conducive to realizing the electrical connection between the second conductive member 132 and the current collecting component outside the pole 12.

[0213] In addition, since the notch of the second groove 1311 is formed on the surface of the first conductive member 131 on the side away from the second receiving groove 12120, it means that the second groove 1311 is open in the direction away from the active material coating portion 21, so that the portion of the groove wall of the first conductive member 131 used to define the second groove 1311 is located between the second receiving groove 12120 and the second conductive member 132 to separate the second receiving groove 12120 from the second conductive member 132, thereby preventing the electrolyte entering the second groove 1311 from contacting the second conductive member 132 and reducing leakage of the electrolyte.

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

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

[0216] Of course, in other embodiments of the present application, the cooperation between the cover plate 13 and the pole 12 is not limited to being embedded in the second receiving groove 12120. The cover plate 13 can also be directly covered on the outside of the pole 12, that is, directly covered at the notch of the second receiving groove 12120, so as to facilitate the cooperation with the convergence component of the battery 100, which is not limited in this embodiment.

[0217] In some embodiments, the housing 11 includes a housing cover 112 and a housing body 111 . The housing body 111 has an opening 1110 . The housing cover 112 covers the opening 1110 . A pole 12 is disposed on the wall of the housing cover 112 and / or the housing body 111 opposite to the opening 1110 .

[0218] For example, all poles 12 may be disposed on the shell cover 112. For example, one pole 12 may be disposed on the shell cover 112, and the remaining poles 12 may be disposed on the shell body 111. Since the size of the shell cover 112 is relatively small, the size of the mold or the fixture may be reduced, which is conducive to reducing costs.

[0219] Of course, at least one pole 12 can also be arranged on the wall of the shell body 111 opposite to the opening 1110. In this way, the electrode assembly 2 enters the shell body 111 along the opening 1110, and the pole ear 22 directly faces the pole 12, so that the pole ear 22 can be easily connected to the pole 12, thereby improving the assembly efficiency of the battery cell 10.

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

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

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

[0223] The electric device 1000 includes the battery cell 10 described in any of the above solutions, or includes the battery 100 described in the above solutions, and the battery 100 is used to provide electric energy for the electric device 1000. The electric device 1000 can be any of the above-mentioned devices or systems using the battery 100.

[0224] In the technical solution of the embodiment of the present application, by adopting the above-mentioned battery 100, the reliability of the use of the electric device 1000 can be improved.

[0225] Please refer again Figure 8-Figure 14 , and further refer to Fig.24 , Fig.24 This is a flow chart of the preparation of the electrode assembly 2 provided in some embodiments of the present application. The present application provides a method for preparing the electrode assembly 2.

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

[0227] Providing the electrode assembly 2 as an input material;

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

[0229] Welding the overlapping areas Z1 of the plurality of pole tabs 221 to form a first welding portion 2211 of the pole tab portion 22;

[0230] The offset regions Z2 of the plurality of electrode tabs 221 are welded to form a second welding portion 2212 of the electrode tab portion 22 . The second welding portion 2212 is located at one end of the first welding portion 2211 away from the active material coating portion 21 .

[0231] Specifically, the overlapping area Z1 may be welded first to form the first welding part 2211, and then the portion of the dislocation area Z2 away from the active material coating part 21 may be welded to form the second welding part 2212; or the portion of the dislocation area Z2 away from the active material coating part 21 may be welded first to form the second welding part 2212, and then the overlapping area Z1 may be welded to form the first welding part 2211.

[0232] In the technical solution of the embodiment of the present application, the overlapping area Z1 of multiple pole lugs 221 is welded to form a first welding portion 2211, and the offset area Z2 of multiple pole lugs 221 is welded away from the active material coating portion 21 to form a second welding portion 2212. The area of ​​the welding region of the multiple pole lugs 221 can be increased. On the one hand, the utilization rate of the pole lug portion 22 is improved, which is beneficial to improve the capacity of the battery cell 10 and reduce the over-current temperature rise. On the other hand, when the pole lug portion 22 is welded to the pole column 12, the second welding portion 2212 can better support the welding nozzle than the fluffy multiple pole lugs, thereby reducing the problem of welding defects caused by the welding nozzle in the related technology being pressed onto the fluffy area of ​​the multiple pole lugs 221, reducing the cutting requirements for the pole lug portion 22 after welding, saving costs, and improving the fast charging performance of the battery cell 10.

[0233] Please refer again Figure 8-Figure 11 , welding the overlapping area Z1 of multiple pole tabs 221, including: clamping the overlapping area Z1 of multiple pole tabs 221 between the first ultrasonic welding seat 81 and the first ultrasonic welding head 82, so as to weld the overlapping area Z1 of the pole ear part 22 by ultrasonic welding to form the first welding part 2211 of the pole ear part 22.

[0234] Specifically, after the multiple pole tabs 221 are paired, the multiple pole tabs 221 are stacked, and the stacked multiple pole tabs 221 have an overlapping area Z1 and a misaligned area Z2. The overlapping area Z1 is clamped between the first ultrasonic welding seat 81 and the first ultrasonic welding head 82, and friction is generated between any two adjacent pole tabs 221 to cause melting, so that the multiple pole tabs 221 are welded together in the overlapping area Z1, thereby forming a first welding portion 2211.

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

[0236] Please refer again Figure 12-14, welding the misaligned areas Z2 of multiple pole tabs 221, including: clamping the misaligned areas Z2 of multiple pole tabs 221 between the second ultrasonic welding seat 91 and the second ultrasonic welding head 92, and welding the misaligned areas Z2 of the pole ear part 22 by ultrasonic welding to form the second welding part 2212 of the pole ear part 22.

[0237] Specifically, the position of the dislocation region Z2 away from the active material coating portion 21 is clamped between the second ultrasonic welding seat 91 and the second ultrasonic welding head 92, and friction is generated between any two adjacent pole tabs 221 to melt, thereby welding the multiple pole tabs 221 together at the position of the dislocation region Z2 away from the active material coating portion 21, thereby forming a second welding portion 2212.

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

[0239] Please refer again Figure 12-14 One of the surfaces of the second ultrasonic welding seat 91 and the second ultrasonic horn 92 facing each other extends along the height of the pole ear portion 22, and the other of the surfaces of the second ultrasonic welding seat 91 and the second ultrasonic horn 92 facing each other is inclined relative to the height direction of the pole ear portion 22.

[0240] That is to say, the first surface 2214 of the second welding portion 2212 formed after welding can be flush with the first welding portion 2211. When welding the pole ear portion 22 and the pole 12, a larger welding nozzle can be used so that a part of the welding nozzle can be pressed on the first welding portion 2211 and the other part can be pressed on the second welding portion 2212, that is, the first welding portion 2211 and the second welding portion 2212 can support the welding nozzle at the same time, which not only reduces the difficulty of welding, but also reduces the problem of welding defects caused by the welding nozzle being pressed onto the fluffy area of ​​multiple pole ear sheets in the related technology, reduces the cutting requirements for the pole ear portion after welding, saves costs, and improves the fast charging performance of the battery cell 10.

[0241] In the above technical solution, by adopting the second ultrasonic welding seat 91 and the second ultrasonic welding head 92, the dislocation area Z2 can be ultrasonically welded to form a preset second welding portion 2212. On the one hand, it is convenient to decide whether to cut according to needs later, thereby improving the convenience of cutting. On the other hand, it can reduce the difficulty of welding, reduce welding defects and improve the welding quality.

[0242] In some embodiments, the angle α between the surfaces of the second ultrasonic welding base 91 and the second ultrasonic horn 92 facing each other is smaller than the angle β between the two oppositely disposed wall surfaces of the dislocation region Z2. In this way, the second ultrasonic welding base 91 and the second ultrasonic horn 92 can clamp the portion of the dislocation region Z2 away from the active material coating portion 21, thereby improving the welding quality.

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

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

[0245] In the above technical scheme, by welding the misaligned area Z2 on at least one side of the overlapping area Z1 to form a third welding portion 2213, on the one hand, the area of ​​the welding area of ​​the multiple pole lugs 221 can be increased, thereby improving the utilization rate of the pole lug portion 22, which is beneficial to increasing the capacity of the battery cell 10 and reducing the over-current temperature rise; on the other hand, it can reduce the problem of welding defects caused by the welding nozzle in the related technology being pressed onto the fluffy area of ​​the multiple pole lugs 221, and can also facilitate the pole lug portion 22 to pass through the through-hole on the pole column 12.

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

[0247] Specifically, the misaligned region Z2 after stacking the plurality of tab sheets 221 includes two side misaligned regions Z22 , which are located on both sides of the overlapping region Z1 in the width direction, and at least one side misaligned region Z22 is welded to form a third welding portion 2213 .

[0248] In the above technical scheme, by welding the misaligned area Z2 on at least one side of the overlapping area Z1 to form a third welding portion 2213, on the one hand, the area of ​​the welding area of ​​the multiple pole lugs 221 can be increased, thereby improving the utilization rate of the pole lug portion 22, which is beneficial to increasing the capacity of the battery cell 10 and reducing the over-current temperature rise; on the other hand, it can reduce the problem of welding defects caused by the welding nozzle in the related technology being pressed onto the fluffy area of ​​the multiple pole lugs 221, and can also facilitate the pole lug portion 22 to pass through the through-hole on the pole column 12.

[0249] Please refer to Fig.17 In some further embodiments, before welding to form the third welding portion 2213, it also includes: bending a first portion of at least one side dislocation zone Z22 along a direction close to the active material coating portion 21 toward the remaining second portion of the side dislocation zone Z22, and then stacking and welding them together to form the third welding portion 2213.

[0250] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. An electrode assembly, characterized in that: include: Active material coating unit; The pole ear portion is connected to the active material coating portion, and the pole ear portion includes a plurality of stacked pole ear sheets, and the plurality of pole ear sheets have overlapping areas and offset areas after being stacked, the overlapping areas are welded to form a first welding portion, and the offset areas are welded at least at a position away from the active material coating portion to form a second welding portion.

2. The electrode assembly according to claim 1, characterized in that: The first welding portion and the second welding portion are connected to each other.

3. The electrode assembly according to claim 1, characterized in that: Along the width direction of the pole ear portion, the ratio range of the width dimension of the first welding portion to the width dimension of the second welding portion is: 0.8-1.2; and / or, Along the width direction of the pole ear portion, the ratio of the width dimension of the first welding portion to the width dimension of the pole ear portion is in the range of 0.6-1; Along the height direction of the pole ear portion, the height dimension ratio of the second welding portion to the first welding portion is 0.08-0.2; and / or, Along the height direction of the pole ear portion, a height dimension ratio between the first welding portion and the pole ear portion is 0.45-0.

65.

4. The electrode assembly according to any one of claims 1 to 3, characterized in that: Along the height direction of the pole ear portion, the height dimension of the second welding portion is 1 mm-2 mm.

5. The electrode assembly according to claim 1, characterized in that: The thickness of the second welding portion gradually decreases in a direction away from the first welding portion.

6. The electrode assembly according to claim 5, characterized in that: The second welding portion has two oppositely disposed first surfaces and second surfaces, and at least one of the first surface and the second surface is disposed obliquely relative to the height direction of the pole lug portion.

7. The electrode assembly according to claim 6, characterized in that: The maximum distance between the first surface and the second surface is 0.5 mm-1 mm.

8. The electrode assembly according to claim 6 or 7, characterized in that: The first surface extends along the height direction of the pole lug portion, the second surface is arranged obliquely relative to the height direction of the pole lug portion, and a distance between the first surface and the second surface gradually decreases along a direction away from the first welding portion.

9. The electrode assembly according to claim 8, characterized in that: The angle between the first surface and the second surface is 10°-45°.

10. The electrode assembly according to any one of claims 1 to 9, characterized in that: The first welding portion and the second welding portion are respectively formed by ultrasonic welding.

11. The electrode assembly according to any one of claims 1 to 10, characterized in that: The misaligned area is located at least on one of the two sides of the overlapping area and is welded to form a third welding portion.

12. A battery cell, characterized in that: include: A shell body provided with a pole; An electrode assembly is arranged in the shell, the pole ear portion is connected to the pole, and the electrode assembly is the electrode assembly according to any one of claims 1-11.

13. The battery cell according to claim 12, characterized in that: The pole is provided with a receiving portion, and at least a portion of the pole ear extends into the receiving portion and is welded to the pole.

14. The battery cell according to claim 13, characterized in that: The accommodating portion includes a first accommodating groove, the surface of the pole facing the active material coating portion is the inner end face of the pole, the notch of the first accommodating groove is formed on the inner end face of the pole, and at least part of the pole ear portion is accommodated in the first accommodating groove.

15. The battery cell according to claim 13, characterized in that: The accommodating portion includes a second accommodating groove, the surface of the pole away from the active material coating portion is the outer end face of the pole, the notch of the second accommodating groove is formed on the outer end face of the pole, the second accommodating groove is connected to the interior of the shell through a through hole, the pole ear portion is penetrated through the through hole and is at least partially accommodated in the second accommodating groove.

16. The battery cell according to any one of claims 12 to 15, characterized in that: The shell comprises a shell cover and a shell body with an opening, wherein the shell cover covers the opening, and the pole is arranged on a wall of the shell cover and / or the shell body opposite to the opening.

17. A battery, characterized in that: The invention comprises a battery cell according to any one of claims 12 to 16.

18. An electrical device, characterized in that: Comprising a battery according to claim 17.

19. A method for preparing an electrode assembly, characterized in that: The following steps are involved: Provide incoming materials for electrode components; Stacking a plurality of tab sheets of the electrode assembly to form a tab portion; Welding the overlapping area of ​​the pole lug portion to form a first welding portion; The misaligned region of the electrode ear portion is welded to form a second welding portion, wherein the second welding portion is located at an end of the first welding portion away from the active material coating portion.

20. The method for preparing an electrode assembly according to claim 19, characterized in that: The welding of the overlapping area of ​​the pole lug portion comprises: The overlapping area of ​​the pole lugs is clamped between a first ultrasonic welding seat and a first ultrasonic horn, and the overlapping area of ​​the pole lugs is welded by ultrasonic welding to form the first welding portion.

21. The method for preparing an electrode assembly according to claim 19 or 20, characterized in that: The step of welding the misaligned region of the pole ear portion comprises: The misaligned region of the pole ear portion is clamped between a second ultrasonic welding seat and a second ultrasonic horn, so as to form the second welding portion by ultrasonic welding the misaligned region of the pole ear portion.

22. The method for preparing an electrode assembly according to claim 21, characterized in that: One of the surfaces of the second ultrasonic welding seat and the second ultrasonic horn facing each other extends along the height of the pole lug portion, and the other is arranged obliquely with respect to the height direction of the pole lug portion.

23. The method for preparing an electrode assembly according to claim 21 or 22, characterized in that: The angle between the surfaces of the second ultrasonic welding seat and the second ultrasonic horn facing each other is smaller than the angle between two oppositely disposed wall surfaces of the misaligned area.

Images