Battery monomer, battery, electric device, ultrasonic welding head and ultrasonic welding device

Abstract

The invention provides a battery monomer, a battery, a power utilization device, an ultrasonic welding head and an ultrasonic welding device, and belongs to the technical field of batteries. Wherein the battery monomer comprises a shell, a pole and an electrode assembly, the pole is arranged in the shell, the electrode assembly comprises an active material coating part arranged in the shell and a tab part electrically connected with the active material coating part and the pole, the tab part comprises a plurality of tab pieces, and the plurality of tab pieces are stacked and connected to form a furling part; the furling part is provided with a first area and a second area, the compaction degree of the plurality of tab pieces in the first area is greater than that of the plurality of tab pieces in the second area, a connecting part is formed at the position, used for being electrically connected with the pole column, of the furling part, and at least part of the edge of the connecting part on the furling part falls in the first area. According to the battery monomer, the problem of cracks on the edge of the connecting part can be improved, the conductive yield and the connecting strength of the tab part and the pole are improved, and the reliability of the battery monomer is improved.

Description

Technical Field

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

[0002] In recent years, new energy vehicles have developed by leaps and bounds. In the field of electric vehicles, power batteries, as the power source of electric vehicles, play an irreplaceable and important role. Among them, power batteries include several battery cells, however, the reliability of battery cells needs to be improved. Summary of the invention

[0003] The embodiments of the present application provide a battery cell, a battery, an electrode assembly, an ultrasonic welding head and an ultrasonic welding device, which can improve the reliability of the battery cell.

[0004] In a first aspect, an embodiment of the present application provides a battery cell, comprising a shell, a pole and an electrode assembly, wherein the pole is arranged in the shell, and the electrode assembly comprises an active material coating portion arranged in the shell, and a pole ear portion electrically connecting the active material coating portion and the pole, wherein the pole ear portion comprises a plurality of pole ear sheets, and the plurality of pole ear sheets are stacked and connected to form a gathered portion, the gathered portion having a first area and a second area, the plurality of pole ear sheets are compacted to a greater extent in the first area than in the second area, a connecting portion is formed at a position of the gathered portion for electrical connection with the pole, and at least a portion of an edge of the connecting portion on the gathered portion falls in the first area.

[0005] In the above technical solution, a plurality of pole ear sheets are arranged with a higher degree of compaction in the first area than in the second area, and the connection portion formed by the position of the gathered portion for electrical connection with the pole is arranged so that at least part of the edge on the gathered portion falls in the first area, so that at least part of the edge of the connection portion is located in the relatively compacted area of ​​the gathered portion, thereby improving the problem of cracks on the edge of the connection portion, improving the conductivity yield and connection strength of the position of the pole ear portion for electrical connection with the pole, and thereby improving the reliability of the battery cell.

[0006] In addition, by arranging that the degree of compaction of multiple pole tabs in the second area is lower than that in the first area, the multiple pole tabs are slightly cold-welded between the layers in the second area. When welding to form a gathered portion, and when welding the gathered portion to a pole or an adapter, the pole tabs in the second area that are slightly cold-welded can be deformed, so as to reduce the tensile stress at the connection between the first area and the second area, thereby improving the problem of cracking of the pole tabs in the boundary area between the first area and the second area. When welding the gathered portion to a pole or an adapter, the pole tabs in the second area that are cold-welded can be deformed, so as to reduce the pulling on the boundary between the first area and the connection part, thereby further reducing the problem of cracks at the edge of the connection part.

[0007] In some embodiments, a portion of the edge of the connecting portion on the gathered portion falls within the second region.

[0008] In the above technical solution, since the degree of compaction of the multiple pole tabs in the second area is smaller than that in the first area, the pole tabs are relatively easy to deform in the second area. When the welding gathered portion forms a connection with the pole or adapter, since the edge of the connection portion on the gathered portion partially falls in the second area, the deformation of the pole tabs in the second area can be better utilized to meet the welding shrinkage requirements, reduce the tensile stress on the edge of the connection portion, and further reduce the problem of cracks on the edge of the connection portion.

[0009] In some embodiments, a portion of the edge of the connecting portion on the surface of the gathered portion is a contour line, the contour line includes a first line segment located in the first area and a second line segment located in the second area, and the length of the first line segment is greater than the length of the second line segment.

[0010] In the above technical solution, since the portion of the contour line falling in the first area is larger than that falling in the second area, the portion of the edge of the connecting portion falling in the first area can be larger than that falling in the second area, thereby more significantly reducing the cracks on the edge of the connecting portion, improving the conductivity yield and connection strength of the position of the pole ear for electrical connection with the pole, and thus improving the reliability of the battery cell.

[0011] In some embodiments, there are multiple first areas, adjacent first areas are separated by a second area, there are multiple first line segments arranged at intervals, the multiple first line segments correspond to the multiple first areas, and adjacent first line segments are connected by a second line segment.

[0012] In the above technical solution, the pole ear piece in the second area spaced between adjacent first areas can more fully exert its deformation effect, meet the welding shrinkage requirements, further reduce the tensile stress on the edge of the connecting part, and thus can more significantly reduce the cracks on the edge of the connecting part, improve the conductivity yield and connection strength of the position of the pole ear used for electrical connection with the pole, and thus improve the reliability of the battery cell.

[0013] In some embodiments, the contour line is a long ring, there are two first areas spaced apart along the width direction of the contour line, the first area is formed as a long strip area extending along the length direction of the contour line, and the two long sides of the contour line fall in the two first areas respectively.

[0014] In the above technical solution, the structural shape of the connecting part is simple and is easy to be formed by laser welding or the like. Moreover, the number and distribution positions of the first areas are set in this way, so that the space of the storage part can be fully utilized, so that when a strip-shaped connecting part is formed, the first line segment is longer than the second line segment, and the portion where the edge of the connecting part falls between the two first areas can more easily meet the welding shrinkage requirements through deformation. The portion where the edge of the connecting part falls in the first area is larger, so that the area where cracks are not easily formed is larger, thereby more significantly improving the conductivity yield and connection strength of the position of the pole ear for electrical connection with the pole, thereby improving the reliability of the battery cell.

[0015] In some embodiments, the width direction of the contour line is the longitudinal direction, and the longitudinal distance between the two first regions is G. 0 , the longitudinal width of the first region is W 0 , the connection is a weld and the maximum longitudinal weld width is W 1 , the standard deviation of the maximum longitudinal weld width is [σ], and the longitudinal fluctuation value of the gathering part assembly is ω; where W 1 -3[σ]-ω≥G 0 , and W 1 +3[σ]+ω≤G 0 +2W 0 .

[0016] In the above technical solution, the width of the weld can be made to reliably fall within the first region on both sides, thereby effectively reducing cracks at the weld edges, improving the conductivity yield and connection strength of the pole ear portion for electrical connection with the pole, and thereby improving the reliability of the battery cell.

[0017] In some embodiments, the two first regions are arranged in parallel and symmetrically.

[0018] In the above technical solution, the space of the gathered portion can be fully utilized to increase the area and coverage of the first region, and the second region can be separated by two second regions, thereby facilitating the processing of the first region and the second region, and reducing the processing difficulty of the gathered portion. Moreover, when welding the pole ear portion and the gathered portion, since the two first regions are arranged in parallel and symmetrically, the ultrasonic welding head can weld between the two first regions along the length direction of the first region, so that the edges of the width of the weld can easily fall on the first regions on both sides, thereby reducing the welding difficulty and improving the welding efficiency.

[0019] In some embodiments, the ear portion is formed into a gathered portion by ultrasonic welding, and the total area of ​​all first regions is S less than or equal to the critical area S 0 ;in, P is the pressure of compressed air input to the ultrasonic welding device; D is the cylinder diameter of the ultrasonic welding device, γ is the pressure ratio of the first area, [σ 0.2] is the yield strength of the tab, It is the residual strength coefficient of the tab under the action of welding heat.

[0020] In the above technical solution, the pressure in the first region during ultrasonic pre-welding can be greater than or equal to the yield strength of the pole tab under the action of welding heat softening, so that the pole tab can produce better plastic deformation, so that the first region can obtain a more effective compaction effect.

[0021] In some embodiments, the first region is the region of the gathered portion that is most compacted.

[0022] In the above technical solution, at least part of the edge of the connection portion formed by the gathered portion for electrical connection with the pole is arranged in the first area with the greatest degree of compaction, which can more effectively improve the problem of cracks on the edge of the weld, and more effectively improve the conductivity yield and connection strength of the position of the pole ear for electrical connection with the pole, thereby improving the reliability of the battery cell.

[0023] In some embodiments, the gather is comprised of a first region and a second region.

[0024] In the above technical solution, the structure and processing of the gathering portion can be simplified, the processing difficulty of the gathering portion can be reduced, and the processing quality of the gathering portion can be improved.

[0025] In some embodiments, the gathered portion is directly welded to the pole, so that the gathered portion and the pole together form a connection portion.

[0026] In the above technical solution, the problem of cracks on the edge of the first weld formed between the gathered portion and the pole can be improved, the conductivity yield and connection strength between the pole ear and the pole can be improved, and the reliability of the battery cell can be improved.

[0027] In some embodiments, the battery cell further includes a transfer plate, the retracted portion is indirectly connected to the pole via the transfer plate, and the retracted portion and the transfer plate are directly welded to form a connection portion together.

[0028] In the above technical solution, the problem of cracks on the edge of the second weld formed between the gathered portion and the adapter plate can be improved, the conductivity yield and connection strength between the pole ear portion and the adapter plate can be improved, and the reliability of the battery cell can be improved.

[0029] In some embodiments, the pole includes a pole body mounted on the housing, a receiving groove is formed on the pole body, and at least a portion of the retracted portion is received in the receiving groove and welded to the pole body.

[0030] In the above technical solution, by accommodating at least part of the folded portion in the accommodating groove, at least part of the folded portion occupies the space in the accommodating groove, thereby reducing the space occupied by the folded portion in the shell, saving space in the shell to accommodate a larger volume of active material coating part, which is beneficial to improving the energy density of the battery cell, or when the energy density of the battery cell remains unchanged, it is beneficial to reduce the size of the battery cell.

[0031] In some embodiments, a accommodating cavity is formed in the shell, and the accommodating groove is open in a direction away from the accommodating cavity. A connecting hole is provided on the pole body, and the connecting hole passes through the groove wall on one side of the accommodating groove close to the accommodating cavity, and connects the accommodating cavity and the accommodating groove, and the gathering portion is passed through the connecting hole.

[0032] In the above technical solution, when injecting electrolyte into the battery cell, the electrolyte can be injected into the receiving groove and then flow toward the receiving cavity through the connecting hole, wherein the receiving groove can play the role of buffering the electrolyte to improve the problems of electrolyte splashing and overflow. Moreover, the side wall of the receiving groove can block the electrolyte splashing to a certain extent, reduce the pollution caused by the electrolyte to the outside, and facilitate rapid injection. Moreover, since there is no need to open a separate injection channel on the shell, there is no need to perform special processing on the shell, which is conducive to reducing the structural complexity and processing difficulty of the shell.

[0033] In some embodiments, the pole includes a pole cover plate that covers the pole body, a liquid injection hole that can be communicated with the receiving groove is formed on the pole cover plate, and the battery cell also includes a sealing structure for sealing the liquid injection hole.

[0034] In the above technical solution, by processing the injection hole on the pole cover, the opening is relatively small and located outside, so that the injection inlet can be reliably sealed more easily through the sealing structure, thereby improving the working reliability of the battery cell and realizing flexible and diversified design of the sealing structure.

[0035] In a second aspect, an embodiment of the present application further provides a battery, comprising a battery cell of any of the above-mentioned solutions.

[0036] In the above technical solution, since the reliability of the battery cell according to the embodiment of the present application is improved, it is beneficial to improve the performance of the battery.

[0037] In a third aspect, an embodiment of the present application further provides an electrical device, comprising a battery according to any of the above solutions.

[0038] In the above technical solution, since the performance of the battery is improved, it is beneficial to improve the working power performance of the electrical device.

[0039] In the fourth aspect, an embodiment of the present application also provides an ultrasonic welding head for processing the converged part of any of the above-mentioned schemes, the welding surface of the ultrasonic welding head includes a first face portion and a second face portion, the first face portion protrudes from the second face portion, the first face portion corresponds to processing a first area, and the second face portion corresponds to processing a second area.

[0040] In the above technical solution, when ultrasonically pre-welding the gathered portion, the first face is protruded and the area is smaller than the total area of ​​the welding face, so that the first face contacts the pole tab first, and the pressure area is smaller, so that the local pressure can be increased, and the pre-welding force is concentrated on the position of the first area under the condition that the pre-welding pressure and energy remain unchanged, so that the first area with a relatively large degree of compaction is formed, so that the first area is close to or becomes a solid plate structure. In short, according to the ultrasonic welding head of the embodiment of the present application, by setting the welding surface of the ultrasonic welding head to include a first face and a second face, and the first face protrudes from the second face, the first area processed by the first face can be made more compact than the second area processed by the second face.

[0041] In some embodiments, the first surface is a convex curved surface.

[0042] In the above technical solution, compared with the first surface being a flat surface, the convex curved surface can further reduce the preferred contact area, further increase the local pressure, and thus improve the compaction degree of pre-welding, and compared with the first surface being a sharp folded surface, it can avoid the problem of the first surface and the pole tab being sharply contacted, resulting in the pole tab being crushed. In short, it can protect the pole tab, improve the welding yield, and improve the problem of cracks at the pre-welding position, while improving the compaction degree of the first surface to the pole tab.

[0043] In some embodiments, the cross-section of the first surface is arc-shaped and has a radius of 0.2 mm-0.5 mm.

[0044] In the above technical solution, since the radius of the first face is not too large, the first face can have a certain protruding height when the width is constant, and since the radius of the first face is not too small, the first face can have a certain width when the protruding height is constant. Therefore, the width and protruding height of the first face can enable the first area to obtain a larger pre-welding pressure and achieve a better deep welding compaction effect, and enable the second area to achieve a shallow welding effect and have a certain rigidity.

[0045] In some embodiments, the connection between the first face portion and the second face portion is connected by a smooth transition of a curved surface.

[0046] In the above technical solution, during the process of pre-welding the pole ear portion by the ultrasonic horn, when the welding surface of the ultrasonic horn contacts the pole ear portion and is subjected to reaction, since the connection between the first face portion and the second face portion is connected by a smooth transition of the curved surface, the stress concentration at the connection between the first face portion and the second face portion can be reduced, which causes the welding surface to crack at the junction of the first face portion and the second face portion, thereby improving the reliability of the ultrasonic horn for pre-welding the pole ear portion, which is beneficial to prolonging the service life of the ultrasonic horn. Therefore, according to the ultrasonic horn of the embodiment of the present application, the structural reliability of the welding surface of the ultrasonic horn can be improved, and the structural stability of the ultrasonic horn in the process of pre-welding the pole ear portion can be improved, thereby improving the reliability of the ultrasonic horn for pre-welding the pole ear portion, which is beneficial to prolonging the service life of the ultrasonic horn.

[0047] In some embodiments, the first surface is in an elongated strip shape and there are two first surfaces disposed in parallel.

[0048] In the above technical solution, the first area can be processed into a long strip shape, and the first area is two and arranged in parallel. In this way, when welding the closing part and the pole or adapter, the weld can extend along the length direction of the first area, and the edges on both sides of the width of the weld can fall in the first areas on both sides respectively, so that most of the edges of the weld are not easy to crack. Moreover, the part of the pole tab located in the second area between the two first areas is easy to deform, which meets the welding shrinkage requirements and improves the problem of cracks on both sides of the width of the weld due to stress pulling. Moreover, the space of the closing part can be fully utilized to increase the area and coverage of the first area, which is conducive to increasing the length of the weld, thereby improving the reliability of the connection between the pole ear and the pole or adapter, and facilitating the processing of the first area and the second area, reducing the difficulty of processing the closing part.

[0049] In some embodiments, the protrusion height of the first surface relative to the second surface is 0.05 mm-0.2 mm.

[0050] In the above technical solution, the protruding height of the first surface is not too short, so that the first area can obtain a larger pre-welding pressure and achieve a better deep welding compaction effect, and the protruding height of the first surface is not too high, so that the second area can also obtain a pre-welding pressure and achieve a shallow welding effect, and can have a certain rigidity.

[0051] In a fifth aspect, an embodiment of the present application further provides an ultrasonic welding device, comprising a welding seat and an ultrasonic welding head of any of the above-mentioned schemes.

[0052] In the above technical scheme, since the ultrasonic welding device includes the ultrasonic welding head of any of the above schemes, it is conducive to processing the above-mentioned pole ear portion having the first area and the second area, which is conducive to improving the problem of cracks on the edge of the connection portion formed by the position of the pole ear portion for electrical connection with the pole, improving the conductivity yield and connection strength of the position of the pole ear portion for electrical connection with the pole, and improving the reliability of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0054] Figure 1 A schematic diagram of the structure of a vehicle provided in some embodiments of the present application;

[0055] Figure 2 An exploded view of the structure of a battery provided in some embodiments of the present application;

[0056] Figure 3 A schematic diagram of the structure of a battery cell provided in some embodiments of the present application;

[0057] Figure 4 A schematic diagram of an orthographic projection of a battery cell provided in some embodiments of the present application;

[0058] Figure 5 For along Figure 4 Sectional view along line AA;

[0059] Figure 6 for Figure 5 A partial enlarged view of the B part circled in the middle;

[0060] Figure 7 A schematic diagram of the connection between the pole ear and the pole provided in some embodiments of the present application;

[0061] Figure 8 An exploded view of an electrode assembly and a cover plate with a pole provided in some embodiments of the present application;

[0062] Fig. 9 for Figure 8 A partial enlarged view of the C section circled in the middle;

[0063] Fig.10 A schematic diagram of the connection between an electrode assembly and a cover plate provided with a pole provided in some embodiments of the present application;

[0064] Fig.11 for Fig.10A partial enlarged view of the D portion indicated by the middle circle;

[0065] Fig.12 A schematic diagram of the cooperation between a battery cell and a busbar component provided in some embodiments of the present application;

[0066] Fig.13 A schematic diagram of connecting a pole ear portion and a pole via an adapter sheet provided in some embodiments of the present application;

[0067] Fig.14 A schematic diagram of a pole ear portion processed by an ultrasonic welding device provided in some embodiments of the present application;

[0068] Fig.15 for Fig.14 An enlarged view of the ultrasonic horn shown in ;

[0069] Fig.16 A schematic diagram of the structure of an ultrasonic welding head provided in some embodiments of the present application;

[0070] Fig.17 for Fig.16 A partial enlarged view of the E part circled in the middle;

[0071] Fig.18 A schematic diagram of the structure of a welding base provided in some embodiments of the present application;

[0072] Fig.19 for Fig.18 A partial enlarged view of the F part circled in the middle.

[0073] Figures: vehicle 1000; first direction X; second direction Y; third direction Z; battery 100; controller 200; motor 300; box 101; first box body 1011; second box body 1012; battery cell 102; converging component 103; shell 1; accommodating chamber 11; pole 2; pole body 3; accommodating groove 36; connecting hole 37; pole cover plate 4; injection hole 43; adapter plate 5; sealing structure 6; first sealing member 61; second sealing member Component 62; electrode assembly 7; active material coating portion 71; pole ear portion 72; pole ear sheet 721; gathered portion 722; first region 7221; second region 7222; connecting portion 8; edge 81; contour line 82; first line segment 821; second line segment 822; first weld 80; second weld 85; ultrasonic welding device 2000; ultrasonic welding head 400; first welding surface 9; first face portion 91; second face portion 92; welding seat 500; second welding surface 501. DETAILED DESCRIPTION

[0074] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0075] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field of this application; the terms used in the specification of this application 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 drawings and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0076] Reference to "embodiment" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various places 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.

[0077] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" 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 direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0078] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can 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 application generally indicates that the associated objects before and after are in an "or" relationship.

[0079] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0080] The term "plurality" used in the present application refers to two or more (including two).

[0081] In the present application, battery cells may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries or magnesium-ion batteries, etc., and the embodiments of the present application do not limit this. Battery cells may be cylindrical, flat, rectangular or other shapes, etc., and the embodiments of the present application do not limit this. Battery cells are generally divided into three types according to the packaging method: cylindrical battery cells, square battery cells and soft-pack battery cells, and the embodiments of the present application do not limit this.

[0082] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in the present application may include a battery module or a battery pack. A battery module generally includes a plurality of battery cells. A battery pack generally includes a box for encapsulating one or more battery cells or one or more battery modules. The box can prevent liquid or other foreign matter from affecting the charging or discharging of the battery cells.

[0083] A battery cell includes a shell, an electrode assembly and an electrolyte. The shell is used to contain the electrode assembly and the electrolyte. The shell contains at least one electrode assembly, which is composed of a positive electrode sheet, a negative electrode sheet and a separator. The electrode assembly can be a wound structure or a stacked structure. The battery cell mainly relies on the movement of metal ions between the positive electrode sheet and the negative electrode sheet to work.

[0084] The positive electrode sheet can generally include a positive electrode current collector and a positive electrode active material layer, the positive electrode active material layer is directly or indirectly coated on the positive electrode current collector, the positive electrode current collector not coated with the positive electrode active material layer protrudes from the positive electrode current collector coated with the positive electrode active material layer, and the positive electrode current collector not coated with the positive electrode active material layer serves as a positive electrode tab. Taking lithium-ion batteries as an example, the material of the positive electrode current collector can be aluminum, and the material of the positive electrode active material layer can be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganese oxide, etc.

[0085] The negative electrode sheet may generally include a negative electrode current collector and a negative electrode active material layer, wherein the negative electrode active material layer is directly or indirectly coated on the negative electrode current collector, and the negative electrode current collector not coated with the negative electrode active material layer protrudes from the negative electrode current collector coated with the negative electrode active material layer, and the negative electrode current collector not coated with the negative electrode active material layer serves as a negative electrode tab. The material of the negative electrode current collector may be copper, and the material of the negative electrode active material layer may be carbon or silicon, etc.

[0086] In order to ensure that a large current does not melt, there are multiple positive electrode tabs stacked together to form the positive electrode tab, and multiple negative electrode tabs stacked together to form the negative electrode tab. The shell is provided with a pole column, the positive electrode tab is electrically connected to the positive pole column, and the negative electrode tab is electrically connected to the negative pole column.

[0087] In the related art, the stacked multi-layered pole ear sheets are welded together by ultrasonic welding to form a plate-shaped pole ear portion, and then the plate-shaped pole ear portion after welding is welded to the corresponding pole by laser welding to achieve connection and electrical conduction with the pole. However, the welding head usually used in ultrasonic welding is a uniform welding tooth. Due to the insufficient pressure and energy provided by the ultrasonic welding device, the uniform welding tooth cannot make the pole ear portion form a solid plate that is melted into one, but presents a virtual weld plate of multi-layer foil. Therefore, when the pole ear portion is laser welded with the pole, cracks will appear at the edge of the laser weld formed, affecting the conductivity yield and connection strength of the pole ear portion and the pole, thereby affecting the reliability of the battery cell.

[0088] To this end, an embodiment of the present application proposes a battery cell, comprising a shell, a pole and an electrode assembly, wherein the pole is arranged in the shell, and the electrode assembly comprises an active material coating portion arranged in the shell, and a pole ear portion connecting the active material coating portion and the pole, wherein the pole ear portion comprises a plurality of pole ear sheets, and the plurality of pole ear sheets are stacked and connected to form a gathered portion, the gathered portion having a first area and a second area, the degree of compaction of the plurality of pole ear sheets in the first area is greater than the degree of compaction in the second area, the gathered portion is connected to the pole to form a connecting portion, and at least a portion of an edge of the connecting portion on the gathered portion falls in the first area.

[0089] Thus, by setting the compaction degree of the plurality of pole tabs in the first region to be greater than that in the second region, and at least a portion of the edge of the connection portion formed by connecting the gathered portion to the pole column falls on the first region, so that at least a portion of the edge of the connection portion is located in the relatively compacted region of the gathered portion, the problem of cracks on the edge of the connection portion can be improved, the conductivity yield and connection strength of the pole tab portion and the pole column can be improved, and the reliability of the battery cell can be improved. In addition, by setting the compaction degree of the plurality of pole tabs in the second region to be less than that in the first region, the plurality of pole tabs are slightly cold-welded between the layers in the second region. When the gathered portion is formed by welding, and when the gathered portion is welded to the pole column, the deformation of the pole tab in the second region with a slight cold-weld can reduce the tensile stress at the connection between the first region and the second region, improve the problem of cracks on the pole tab in the boundary region between the first region and the second region, and when the gathered portion is welded to the pole column, the deformation of the pole tab in the second region with a cold-weld can reduce the pulling on the boundary between the first region and the connection portion, and further reduce the problem of cracks on the edge of the connection portion.

[0090] The embodiment of the present application provides an electric device using a battery as a power source, and the electric device may be, but is not limited to, a mobile phone, a tablet, a laptop, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, etc. Among them, the electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc., and the spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0091] For the convenience of description, the following embodiments are described by taking a vehicle 1000 as an example of an electrical device according to an embodiment of the present application.

[0092] Please refer to Figure 1 , Figure 1 A schematic diagram of the structure of a vehicle 1000 provided for some embodiments of the present application. The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle, 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 1000, and the battery 100 may be provided at the bottom, head or tail of the vehicle 1000. The battery 100 may be used to power the vehicle 1000, for example, the battery 100 may be used as an operating power source for the vehicle 1000. The vehicle 1000 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 1000.

[0093] In some embodiments of the present application, the battery 100 can not only serve as an operating power source for the vehicle 1000, but also serve as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0094] Please refer to Figure 2 , Figure 2An exploded view of the structure of a battery 100 provided for some embodiments of the present application. The battery 100 includes a case 101 and a plurality of battery cells 102, and the battery cells 102 are accommodated in the case 101. Among them, the case 101 is used to provide an assembly space for the battery cells 102, and the case 101 can adopt a variety of structures. In some embodiments, the case 101 may include a first case body 1011 and a second case body 1012, and the first case body 1011 and the second case body 1012 cover each other, and the first case body 1011 and the second case body 1012 jointly define an assembly space for accommodating the battery cells 102. The second box body 1012 may be a hollow structure with one end open, the first box body 1011 may be a plate-like structure, and the first box body 1011 covers the open side of the second box body 1012, so that the first box body 1011 and the second box body 1012 jointly define an assembly space; the first box body 1011 and the second box body 1012 may also be hollow structures with one side open, and the open side of the first box body 1011 covers the open side of the second box body 1012. Of course, the box body 101 formed by the first box body 1011 and the second box body 1012 may be in various shapes, such as a cylinder, a cuboid, etc.

[0095] In the battery 100, multiple battery cells 102 can be connected in series, in parallel, or in a hybrid connection. A hybrid connection means that multiple battery cells 102 are connected in series and in parallel. Multiple battery cells 102 can be directly connected in series, in parallel, or in a hybrid connection, and then the whole formed by multiple battery cells 102 is accommodated in the box 101; of course, the battery 100 can also be a battery module formed by multiple battery cells 102 connected in series, in parallel, or in a hybrid connection, and then multiple battery modules are connected in series, in parallel, or in a hybrid connection to form a whole, and accommodated in the box 101. The battery 100 may also include other structures, for example, the battery 100 may also include a converging component for realizing electrical welding between multiple battery cells 102.

[0096] Each battery cell 102 may be a secondary battery or a primary battery; it may also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 102 may be cylindrical, flat, or rectangular. Figure 3 In the illustrated embodiment, the length direction of the battery cell 102 is the first direction X, the width direction of the battery cell 102 is the second direction Y, and the height direction of the battery cell 102 is the third direction Z. The first direction X, the second direction Y and the third direction Z are perpendicular to each other.

[0097] In some embodiments of the present application, Figure 4-Figure 6As shown, the battery cell 102 includes: a shell 1, a pole 2 and an electrode assembly 7, the pole 2 is arranged in the shell 1, the electrode assembly 7 includes an active material coating portion 71 arranged in the shell 1, and a pole ear portion 72 connected to the active material coating portion 71, the pole ear portion 72 is electrically connected to the pole 2, wherein "electrical connection" includes direct or indirect connection to achieve electrical conduction, that is, the pole ear portion 72 is directly or indirectly connected to the pole 2 to achieve electrical conduction.

[0098] Exemplarily, a housing cavity 11 is formed inside the housing 1, the active material coating portion 71 is received in the housing cavity 11, the pole 2 is passed through the housing 1, the pole ear portion 72 is welded to the pole 2, and the pole ear portion 72 is directly electrically connected to the pole 2, so that the pole ear portion 72 is electrically connected between the active material coating portion 71 and the pole 2. Alternatively, the pole ear portion 72 is indirectly connected to the pole 2 through the adapter 5 (for example, in combination with the adapter 5). Fig.13 ), for example, the pole ear portion 72 can be welded to one end of the adapter plate 5, and the other end of the adapter plate 5 can be welded to the pole 2, and the pole ear portion 72 is indirectly electrically connected to the pole 2 through the adapter plate 5.

[0099] Combination Figure 7-Figure 9 , the pole ear portion 72 includes a plurality of pole ear sheets 721, and the plurality of pole ear sheets 721 are stacked and connected to form a gathered portion 722, that is, the plurality of pole ear sheets 721 in the gathered portion 722 not only present a stacked arrangement relationship, but also have a connection relationship, such as a welding connection. Among them, the gathered portion 722 has a first region 7221 and a second region 7222, and the compaction degree of the plurality of pole ear sheets 721 in the first region 7221 is greater than the compaction degree of the second region 7222, that is, the interlayer spacing of the plurality of pole ear sheets 721 in the first region 7221 is less than the interlayer spacing in the second region 7222, for example, the interlayer spacing of the first region 7221 can be zero, so as to have a better compaction effect. It is worth noting that the "compaction degree" described in this application refers to the degree of tightness of the interlayer bonding of the multilayer pole ear sheets 721. The larger the interlayer gap, the smaller the compaction degree, and the smaller the interlayer gap, the greater the compaction degree. The minimum interlayer gap can be zero, that is, melted into one, and the compaction degree is the maximum at this time.

[0100] Exemplarily, due to the different compaction degrees of the first region 7221 and the second region 7222, the thickness of the gathering portion 722 in the first region 7221 and the second region 7222 is different, wherein the compaction degree of the plurality of pole tabs 721 in the first region 7221 is greater than that in the second region 7222, and each pole tab 721 is a structure of generally uniform thickness, so that the thickness of the gathering portion 722 in the first region 7221 is smaller than that in the second region 7222, that is, the thickness of the gathering portion 722 in the first region 7221 is less than that in the second region 7222.

[0101] Exemplarily, the pole ear portion 72 is formed into a gathered portion 722 by ultrasonic welding, the first region 7221 is a deep welding region relative to the second region 7222, and the second region 7222 is a shallow welding region relative to the first region 7221. For example, the first region 7221 is formed into a solid plate-shaped compacted structure that is melted into one, and the second region 7222 is formed into a layered virtual welding structure. It should be noted that when a plurality of pole ear sheets 721 are processed into a gathered portion 722 connected together, they are not limited to being formed by ultrasonic welding, and can also be replaced by other methods, such as molecular diffusion welding, resistance welding, etc.

[0102] Combination Figure 6 and Figure 7 ,as well as Fig.10 and Fig.11 The position of the gathered portion 722 for electrical connection with the pole 2 forms a connecting portion 8 , and at least a portion of an edge 81 of the connecting portion 8 on the gathered portion 722 falls in the first area 7221 .

[0103] For example, in combination Figure 6 and Figure 7 , the gathered portion 722 is directly welded to the pole 2, so that the gathered portion 722 and the pole 2 together form a connection portion 8. For example, the gathered portion 722 and the pole 2 are laser welded to form a connection portion 8, and the connection portion 8 is a laser weld, which is recorded as a first weld 80. The edge of the first weld 80 on the gathered portion 722 constitutes an edge 81 of the connection portion 8 on the gathered portion 722, and at least part of the edge of the first weld 80 is located in the first region 7221. It should be noted that the connection between the gathered portion 722 and the pole 2 is not limited to laser welding, and can also be replaced by other methods, such as arc welding, plasma welding, gas welding, electron beam welding, etc. Since the first region 7221 is in a compacted state relative to the second region 7222, the problem of cracks on the edge of the first weld 80 can be improved, and the conductivity yield and connection strength of the position of the pole ear portion 72 for electrical connection with the pole 2 can be improved, thereby improving the reliability of the battery cell 102.

[0104] For example, in combination Fig.13, the gathering portion 722 is indirectly connected to the pole 2 through the adapter 5, and the gathering portion 722 is directly welded to the adapter 5, so that the gathering portion 722 and the adapter 5 together form a connection portion 8. For example, the gathering portion 722 and the adapter 5 are laser welded to form a connection portion 8, and the connection portion 8 is a laser weld, which is recorded as a second weld 85. The edge of the second weld 85 on the gathering portion 722 constitutes an edge 81 of the connection portion 8 on the gathering portion 722, and at least part of the edge of the second weld 85 is arranged in the first area 7221 of the gathering portion 722. It should be noted that the connection between the gathering portion 722 and the adapter 5 is not limited to laser welding, and can also be replaced by other methods, such as arc welding, plasma welding, gas welding, electron beam welding, etc. Since the first region 7221 is in a compacted state relative to the second region 7222 , the problem of cracks on the edge of the second weld 85 can be improved, the conductivity yield and connection strength between the pole ear portion 72 and the adapter plate 5 can be improved, and the reliability of the battery cell 102 can be improved.

[0105] Therefore, by arranging multiple pole ear pieces 721 with a higher degree of compaction in the first area 7221 than in the second area 7222, and making at least a portion of the edge 81 of the connecting portion 8 formed by the gathered portion 722 for electrical connection with the pole 2 fall on the first area 7221, at least a portion of the edge 81 of the connecting portion 8 is located in the relatively compacted area of ​​the gathered portion 722, thereby improving the problem of cracks on the edge 81 of the connecting portion 8, improving the conductivity yield and connection strength of the position of the pole ear portion 72 for electrical connection with the pole 2, and thereby improving the reliability of the battery cell 102.

[0106] In addition, by arranging that the degree of compaction of the plurality of pole tabs 721 in the second region 7222 is lower than that in the first region 7221, the plurality of pole tabs 721 are slightly cold-welded between the layers in the second region 7222. When welding to form the gathered portion 722, and when welding the gathered portion 722 to the pole 2 or the adapter 5, the pole tab 721 in the second region 7222 that is slightly cold-welded can be deformed, thereby reducing the tensile stress at the connection between the first region 7221 and the second region 7222, thereby improving the problem of cracking of the pole tab 721 in the boundary region between the first region 7221 and the second region 7222. When welding the gathered portion 722 to the pole 2 or the adapter 5, the pole tab 721 in the second region 7222 that is cold-welded can be deformed, thereby reducing the pulling on the boundary between the first region 7221 and the weld, thereby further reducing the problem of cracks at the edge 81 of the connecting portion 8.

[0107] In addition, the gathered portion 722 formed by welding, such as ultrasonic welding, has a certain rigidity in both the first region 7221 and the second region 7222, thereby facilitating the assembly of the pole ear portion 72. For example, when the pole 2 has a connecting hole 37, and the pole ear portion 72 needs to pass through the connecting hole 37 and then be welded to the pole 2, the gathered portion 722 has a certain rigidity, which facilitates the insertion of the pole ear portion 72 into the connecting hole 37, thereby improving the assembly efficiency of the pole ear portion 72 and reducing the assembly difficulty.

[0108] Specifically, when the interlayer gap of the multi-layered pole tab 721 is large, there is a large air gap between the layers. When laser welding is performed here with the pole 2, the welding heat of the laser welding is blocked by the large air gap, and the heat stays in the air gap for a long time, which easily burns the pole tab 721 and forms cracks. In the embodiment of the present application, since the multi-layered pole tab 721 in the first area 7221 is a fused-in-one, relatively compacted structure with a small interlayer gap or no interlayer gap, the heat of the laser welding can be conducted faster in the first area 7221, improving the problem of heat staying in a certain place for a long time, burning the pole tab 721 and forming cracks.

[0109] It is worth noting that, in the embodiment of the present application, the type of the pole 2 is not limited, and it can be a negative pole 2 or a positive pole 2. Exemplarily, the pole ear 72 welded to the negative pole 2 is a copper pole ear, and the pole ear 72 welded to the positive pole 2 is an aluminum pole ear, wherein aluminum has the characteristics of large shrinkage and poor fluidity after being heated, while copper has the characteristics of small shrinkage and good fluidity after being heated. Therefore, after the positive pole ear 72 is welded to the positive pole 2, it is easier to form cracking problems, and after the negative pole ear 72 is welded to the negative pole 2, it is not easy to crack.

[0110] Thus, at least the positive electrode ear portion 72 and the positive electrode column 2 can adopt the above-mentioned improvement scheme of "the ear portion 72 includes a plurality of ear pieces 721, the plurality of ear pieces 721 are stacked and connected to form a gathered portion 722, the gathered portion 722 has a first region 7221 and a second region 7222, the plurality of ear pieces 721 are more compacted in the first region 7221 than in the second region 7222, the gathered portion 722 is connected to the electrode column 2 to form a connecting portion 8, and at least part of the edge 81 of the connecting portion 8 on the gathered portion 722 falls in the first region 7221". The negative electrode ear portion 72 and the negative electrode column 2 can adopt the above-mentioned improvement scheme, or they may not adopt the above-mentioned improvement scheme.

[0111] In some embodiments of the present application, the first region 7221 is the region with the highest degree of compaction on the gathered portion 722. Specifically, the gathered portion 722 has multiple regions with different degrees of compaction, wherein the region with the highest degree of compaction, that is, the region with the smallest interlayer spacing, such as the region with the smallest thickness of the gathered portion 722, is the first region 7221. Therefore, by setting at least a portion of the edge 81 of the connecting portion 8 formed by the gathered portion 722 for electrical connection with the pole 2 on the gathered portion 722 in the first region 7221 with the highest degree of compaction, the problem of cracks on the edge 81 of the connecting portion 8 can be more effectively improved, and the conductivity yield and connection strength of the position of the pole ear portion 72 for electrical connection with the pole 2 can be more effectively improved, thereby improving the reliability of the battery cell 102.

[0112] It is worth noting that the number of areas divided by the gathering portion 722 is not limited, and the areas showing different compaction degrees are not limited to only the first area 7221 and the second area 7222. For example, there may also be a third area, a fourth area, and so on. When the first area 7221 is the area with the highest compaction degree, the compaction degree of the second area 7222 is not limited to the compaction degree of other areas (such as the third area, the fourth area, etc.) except the first area 7221.

[0113] In some embodiments, the gathering portion 722 may be composed of only the first area 7221 and the second area 7222, but the number of the first area 7221 and the second area 7222 is not limited, and there may be at least one of each, that is, the gathering portion 722 is composed of at least one first area 7221 and at least one second area 7222, thereby simplifying the structure and processing of the gathering portion 722, reducing the processing difficulty of the gathering portion 722, and improving the processing quality of the gathering portion 722.

[0114] In some embodiments of the present application, Figure 7-Figure 11 , the edge 81 of the connection part 8 on the gathered part 722 partially falls on the second area 7222. That is, the edge 81 of the connection part 8 on the gathered part 722 does not completely fall on the first area 7221, wherein a part of the edge 81 of the connection part 8 on the gathered part 722 falls on the first area 7221, and another part falls on the second area 7222. Therefore, since the compaction degree of the plurality of pole tabs 721 in the second area 7222 is smaller than that in the first area 7221, the pole tabs 721 are relatively easy to deform in the second area 7222. When the gathered part 722 is welded with the pole 2 or the adapter 5 to form the connection part 8, since the edge 81 of the connection part 8 on the gathered part 722 partially falls on the second area 7222, the deformation of the pole tabs 721 in the second area 7222 can be better utilized to meet the welding shrinkage requirements, reduce the tensile stress on the edge 81 of the connection part 8, and further reduce the problem of cracks on the edge 81 of the connection part 8.

[0115] In some embodiments of the present application, Fig.11 , the portion of the edge 81 of the connection portion 8 on the surface of the gathered portion 722 is a contour line 82, and the contour line 82 includes a first line segment 821 located in the first area 7221 and a second line segment 822 located in the second area 7222, and the length of the first line segment 821 is greater than the length of the second line segment 822. In other words, the portion of the contour line 82 that falls in the first area 7221 is larger than the portion that falls in the second area 7222, so that the portion of the edge 81 of the connection portion 8 that falls in the first area 7221 can be larger than the portion that falls in the second area 7222, so that the cracks of the edge 81 of the connection portion 8 can be more significantly reduced, and the conductivity yield and connection strength of the position of the pole ear portion 72 for electrical connection with the pole 2 are improved, thereby improving the reliability of the battery cell 102.

[0116] In some embodiments of the present application, Fig.11 , there are multiple first regions 7221, adjacent first regions 7221 are separated by second regions 7222, there are multiple first line segments 821 arranged at intervals, and multiple first line segments 821 correspond to multiple first regions 7221, that is, each first region 7221 has a first line segment 821, and adjacent first line segments 821 are connected by second line segments 822. Therefore, the pole ear piece 721 of the second region 7222 spaced between adjacent first regions 7221 can more fully exert the deformation effect, meet the welding shrinkage requirements, further reduce the pulling stress on the edge 81 of the connecting portion 8, and further significantly reduce the cracks on the edge 81 of the connecting portion 8, improve the conductivity yield and connection strength of the position of the pole ear portion 72 for electrical connection with the pole 2, and further improve the reliability of the battery cell 102.

[0117] In some embodiments of the present application, Fig.11 , the contour line 82 is a long ring, that is, the contour line 82 is a ring and the length of the contour line 82 is greater than the width, such as a rectangle, an ellipse, a racetrack, etc. The first area 7221 is two and is spaced apart along the width direction of the contour line 82. The first area 7221 is formed as a long strip area extending along the length direction of the contour line 82, that is, the length direction of the first area 7221 extends along the length direction of the contour line 82. The two long sides of the contour line 82 fall on the two first areas 7221 respectively, so that the long side of the contour line 82 constitutes at least part of the first line segment 821, and at least part of the short side of the contour line 82 constitutes the second line segment 822.

[0118] Therefore, the structural shape of the connecting portion 8 is simple and can be easily formed by laser welding or the like. Moreover, the number and distribution positions of the first areas 7221 are set in this way, so that the space of the storage portion can be fully utilized, so that when the strip-shaped connecting portion 8 is formed, the first line segment 821 is longer than the second line segment 822. The portion where the edge 81 of the connecting portion 8 falls between the two first areas 7221 can more easily meet the welding shrinkage requirements through deformation, and the portion where the edge 81 of the connecting portion 8 falls in the first area 7221 is larger, so that the area where cracks are not easily formed is larger, thereby more significantly improving the conductivity yield and connection strength of the position of the pole ear portion 72 for electrical connection with the pole 2, thereby improving the reliability of the battery cell 102.

[0119] For example, Fig.11 As shown, the two first regions 7221 are arranged in parallel and symmetrically. Thus, the space of the gathered portion 722 can be fully utilized, the area and coverage of the first region 7221 can be increased, and the second region 7222 can be separated from the two second regions 7222, thereby facilitating the processing of the first region 7221 and the second region 7222, and reducing the processing difficulty of the gathered portion 722. Moreover, when welding the pole ear portion 72 and the gathered portion 722, since the two first regions 7221 are arranged in parallel and symmetrically, the ultrasonic welding head 400 can weld between the two first regions 7221 along the length direction of the first region 7221, so that the edges on both sides of the width of the weld can easily fall on the first regions 7221 on both sides, thereby reducing the welding difficulty and improving the welding efficiency.

[0120] In some embodiments of the present application, Fig.11 As shown, the width direction of the contour line 82 is the longitudinal direction, and the longitudinal distance between the two first regions 7221 is G 0 , the longitudinal width of the first region 7221 is W 0 The connection portion 8 is a weld (such as the first weld 80 or the second weld 85) and the maximum longitudinal weld width is W 1 , the standard deviation of the maximum longitudinal weld width is [σ], the longitudinal fluctuation value of the assembly of the gathering portion 722 is ω (for example, the longitudinal fluctuation value generated by the assembly of the gathering portion 722 and the pole 2 or the adapter 5), for example, ω can be about 1 mm; wherein, W 1 -3[σ]-ω≥G 0 , and W 1 +3[σ]+ω≤G 0 +2W 0. In this way, the edges on both sides of the width of the weld can be reliably placed in the first area 7221, so as to effectively reduce the cracks on the edge 81 of the connecting portion 8, improve the conductivity yield and connection strength of the position of the pole ear portion 72 for electrical connection with the pole 2, and thus improve the reliability of the battery cell 102. Among them, the standard deviation (Standard Deviation) is a mathematical term, which is the arithmetic square root of the arithmetic mean (ie: variance) of the square of the deviation from the mean, and is represented by [σ]. The standard deviation is also called the standard deviation, or the experimental standard deviation, and is most commonly used in probability statistics as a measurement basis for the degree of statistical distribution. According to the customary design in engineering, a fluctuation of three times the standard deviation [σ] is taken.

[0121] In some embodiments of the present application, the ear portion 72 is formed into a gathered portion 722 by ultrasonic welding. The total area of ​​all first regions 7221 is S less than or equal to the critical area S 0 ,in, P is the pressure of compressed air input to the ultrasonic welding device; D is the cylinder diameter of the ultrasonic welding device, wherein, when the specific type of the ultrasonic welding device is selected, the pressure of compressed air input to the ultrasonic welding device and the cylinder diameter of the ultrasonic welding device can be determined, γ is the pressure ratio of the first area 7221, that is, the ratio of the input pressure of the ultrasonic welding device 2000 during ultrasonic welding to the first area 7221 to the total input pressure, which can be about 80%, [σ 0.2 ] is the yield strength of the tab 721, is the residual strength coefficient of the pole tab 721 under the action of welding heat, which can be about 40%. 0.2 ] is the strength when 0.2% yield occurs, which can be measured by experiment. For example, after the material type of the pole piece 721 is determined, the sample can be designed for experiment according to "Tensile Test of Metal Materials" (GB / T 228.1-2010, GB / T 228.2-2015) (reference GB / T228.1-2010 Tensile Test of Metal Materials Part 1: Room Temperature Test Method [S], Beijing: China Standards Press, 2011: 6-15; GB / T 228.2-2015 Tensile Test of Metal Materials Part 2: High Temperature Test Method [S]. Beijing: China Standards Press, 2015: 3-8).

[0122] For example, Fig.11 As shown, the first region 7221 is a rectangle, and its area is the product of the length and width of the first region 7221. For example, the length of the first region 7221 is L 0 , width W 0 , the area of ​​the first region 7221 is: L 0 ×W 0, the total area of ​​the two first regions 7221 is S=2L 0 ×W 0 Thus, the pressure of the first region 7221 during ultrasonic pre-welding can be greater than or equal to the yield strength of the pole tab 721 under the action of welding heat softening, so that the pole tab 721 can be better plastically deformed, so that the first region 7221 can obtain a more effective compaction effect.

[0123] In some embodiments of the present application, Figure 6 As shown, the pole 2 includes a pole body 3 mounted on the housing 1, and a receiving groove 36 is formed on the pole body 3, and at least a portion of the retracted portion 722 is received in the receiving groove 36. Therefore, by receiving at least a portion of the retracted portion 722 in the receiving groove 36, at least a portion of the retracted portion 722 occupies the space in the receiving groove 36, so that the space occupied by the retracted portion 722 in the housing 1 can be reduced, and the space in the housing 1 can be saved to accommodate a larger volume of the active material coating portion 71, so as to improve the energy density of the battery cell 102, or when the energy density of the battery cell 102 remains unchanged, it is beneficial to reduce the size of the battery cell 102.

[0124] In some embodiments of the present application, Figure 5 and Figure 6 As shown, a housing 1 is formed with a housing cavity 11, and a housing groove 36 is open in a direction away from the housing cavity 11. A connecting hole 37 is provided on the pole body 3, and the connecting hole 37 penetrates the groove wall of the housing groove 36 on one side close to the housing cavity 11, and connects the housing cavity 11 with the housing groove 36, and the retracting portion 722 is provided in the connecting hole 37. Thus, when the electrolyte is injected into the battery cell 102, the electrolyte can be injected into the housing groove 36, and then flow toward the housing cavity 11 through the connecting hole 37, wherein the housing groove 36 can play the role of buffering the electrolyte to improve the problems of electrolyte splashing and overflow. Moreover, the side wall of the housing groove 36 (i.e., the groove wall extending from the notch of the housing groove 36 toward the housing cavity 11) can block the electrolyte from splashing to a certain extent, reduce the pollution caused by the electrolyte to the outside, and facilitate rapid injection. Moreover, since there is no need to separately open an injection channel on the housing 1, there is no need to perform special processing on the housing 1, which is conducive to reducing the structural complexity and processing difficulty of the housing 1.

[0125] It is worth noting that there may be one or more communicating holes 37, and the gathering portion 722 may be provided through at least one of the communicating holes 37. Exemplarily, at least one communicating hole 37 can pass electrolyte, for example, at least one communicating hole 37 is vacant (i.e., the gathering portion 722 is not provided), so that electrolyte can pass through without being hindered by the gathering portion 722, and for another example, at least one communicating hole 37 can still pass electrolyte after the gathering portion 722 is provided.

[0126] In some embodiments, the gathered portion 722 is welded to the pole body 3 to form an electrical connection, thereby realizing the electrode output of the electrode assembly 7 from the pole body 3. Figure 6 As shown, when the receiving groove 36 is open in a direction away from the receiving cavity 11, the retracted portion 722 is welded to the groove wall of the receiving groove 36 on one side close to the receiving cavity 11, thereby improving the compactness of the fit and facilitating the welding operation of the two. Of course, the present application is not limited thereto, and in other embodiments, the retracted portion 722 may also be configured to be welded to the pole cover plate 4 described later to form an electrical connection, which is not limited here.

[0127] In some embodiments of the present application, Figure 6 As shown, the pole 2 includes a pole cover plate 4 covering the pole body 3, and a liquid injection hole 43 that can be communicated with the receiving groove 36 is formed on the pole cover plate 4, and the battery cell 102 also includes a sealing structure 6 for sealing the liquid injection hole 43. In this way, when it is necessary to inject electrolyte into the battery cell 102, the sealing structure 6 is not installed at the liquid injection hole 43 first, or the sealing structure 6 is in a state of opening the liquid injection hole 43, and the electrolyte can be injected into the receiving groove 36 through the liquid injection hole 43. And after the injection, the sealing structure 6 can be installed at the liquid injection hole 43, or the sealing structure 6 can be switched to a state of closing the liquid injection hole 43, so as to seal and close the liquid injection hole 43 to prevent the electrolyte from overflowing and prevent external foreign matter from entering the receiving cavity 11 from the liquid injection hole 43, thereby improving the reliability of the battery cell 102. Therefore, by processing the injection hole 43 on the pole cover 4, the opening is relatively small and located outside, and the injection inlet can be reliably sealed more easily through the sealing structure 6, thereby improving the working reliability of the battery cell 102 and realizing flexible and diversified design of the sealing structure 6.

[0128] In some embodiments, Figure 6 As shown, the pole cover plate 4 does not have a portion that stops at the outside of the sealing structure 6 (i.e., the side away from the accommodating cavity 11), so that the sealing structure 6 is suitable for being installed to the pole cover plate 4 from the outside of the pole cover plate 4 (i.e., the side away from the accommodating cavity 11). In this way, by setting the sealing structure 6 to be installed to the pole cover plate 4 from the outside of the pole cover plate 4 to seal the injection hole 43, the sealing structure 6 is installed after the injection, which can ensure the sealing of the injection hole 43, and the installation position is close to the outside, which is convenient for the rapid assembly of the sealing structure 6. Moreover, the installation of the sealing structure 6 will not have an adverse effect on the connection between the pole body 3 and the pole cover plate 4, ensuring the reliability of the connection between the pole cover plate 4 and the pole body 3.

[0129] The sealing structure 6 can be in a detachable form or in a non-detachable fixed form. For example, when the sealing structure 6 is in a detachable form, it is convenient for maintaining the injection hole 43. For example, when the electrolyte needs to be replenished, the sealing structure 6 can be removed, the injection hole 43 can be opened, and the electrolyte can be replenished and injected into the accommodating cavity 11 through the injection hole 43. Then, the sealing structure 6 can be reinstalled. For example, the sealing structure 6 can be detachably connected to the pole cover plate 4 by means of threads or screws, so as to facilitate disassembly and assembly.

[0130] For example, when the sealing structure 6 is in a non-detachable fixed form, the sealing structure 6 can be fixed to the pole cover plate 4 by welding, riveting, etc., so as to improve the sealing reliability of the sealing structure 6 to the injection hole 43. Figure 6 , the injection hole 43 may be in a multi-segment form, and the sealing structure 6 may include a first sealing member 61 that is interference-fitted with the injection hole 43, and a second sealing member 62 that covers the first sealing member 61 and is welded to the pole cover plate 4. Alternatively, in some embodiments, the second sealing member 62 may be configured to be detachably connected to the pole cover plate 4 by means of a screw-on buckle, so as to limit the first sealing member 61 to a position that is interference-fitted with the injection hole 43.

[0131] In some embodiments of the present application, Figure 6 As shown, at least part of the sealing structure 6 is embedded in the injection hole 43. That is, the sealing structure 6 can be fully embedded in the injection hole 43, or only part of the sealing structure 6 can be embedded in the injection hole 43. Thus, on the one hand, the space in the injection hole 43 can be fully utilized to improve the sealing reliability of the sealing structure 6 to the injection hole 43, and on the other hand, the height of the sealing structure 6 protruding outside the injection hole 43 can be reduced, and the space occupied by the sealing structure 6 outside the pole cover 4 can be reduced, which is conducive to reducing the interference effect on the converging component 103, increasing the connection area between the converging component 103 and the pole cover 4, and improving the flow efficiency.

[0132] It is worth noting that the setting position of the pole 2 on the shell 1 is not limited. For example, the shell 1 may include a shell body and a cover plate. The shell body defines a space with one side open. The cover plate is arranged on the open side of the shell body to form a accommodating chamber 11 between the shell body and the cover plate. At this time, the surface of the side of the shell body opposite to the cover plate is the first shell wall, and the wall surface of the shell body connected between the first shell wall and the cover plate is the second shell wall. At this time, the pole 2 can be arranged on the first shell wall, or on the second shell wall, or on the cover plate. In addition, it should be noted that the positive pole 2 and the negative pole 2 can be located on the same side surface of the shell 1, or can be located on different side surfaces of the shell 1 respectively. For example, the positive pole 2 and the negative pole 2 can be arranged on the cover plate at the same time, or the positive pole 2 and the negative pole 2 can be arranged on the first shell wall at the same time, or one of the positive pole 2 and the negative pole 2 is arranged on the cover plate, and the other is arranged on the first shell wall, and so on.

[0133] According to an embodiment of the present application, a battery 100 is also provided, comprising a battery cell 102 of any of the above solutions. It is worth noting that the battery 100 according to the embodiment of the present application may include a box body or may not include a box body. Therefore, since the reliability of the battery cell 102 according to the embodiment of the present application is improved, it is beneficial to improve the performance of the battery 100.

[0134] For example, Fig.12 As shown, the battery 100 may further include a busbar 103, and there are multiple battery cells 102, and at least two of them are electrically connected through the busbar 103. In this way, multiple battery cells 102 can be connected in series and / or in parallel. For example, when multiple battery cells 102 are connected in series, the pole cover plate 4 of the anode of one battery cell 102 is connected to the pole cover plate 4 of the cathode of the next battery cell 102 through a busbar 103, and at the same time, the pole cover plate 4 of the cathode of the battery cell 102 is connected to the pole cover plate 4 of the anode of the previous battery cell 102 through another busbar 103.

[0135] According to an embodiment of the present application, there is also provided an electric device, comprising a battery 100 according to any of the above solutions, the battery 100 is used to provide electric energy to the electric device. The electric device may be any of the above-mentioned devices or systems using the battery 100. Since the performance of the battery 100 is improved, it is beneficial to improve the working power performance of the electric device.

[0136] like Figure 14-17As shown, according to an embodiment of the present application, an ultrasonic welding head 400 is also provided for processing the gathered portion 722 of the pole ear portion 72 according to any embodiment of the present application, and the welding surface of the ultrasonic welding head 400 (referred to as the first welding surface 9) includes a first surface 91 and a second surface 92, the first surface 91 protrudes from the second surface 92, the first surface 91 corresponds to the processing of the first area 7221, and the second surface 92 corresponds to the processing of the second area 7222. Therefore, according to the ultrasonic welding head 400 of the embodiment of the present application, the first welding surface 9 is provided to include a first face portion 91 and a second face portion 92, and the first face portion 91 protrudes from the second face portion 92. Since the first face portion 91 protrudes from the second face portion 92, when ultrasonically pre-welding the pole ear portion 72, the first face portion 91 contacts the pole ear sheet 721 preferentially relative to the second face portion 92, and the second face portion 92 contacts the pole ear sheet 721 later relative to the first face portion 91. The pre-welding force tends to be concentrated on the portion where the pole ear portion 72 contacts the first face portion 91, so that the compaction degree of the first area 7221 relative to the pole ear portion 72 and the first face portion 91 is relatively large, so that the compaction degree of the first area 7221 processed by the first face portion 91 can be greater than that of the second area 7222 processed by the second face portion 92.

[0137] Specifically, according to the ultrasonic welding head 400 of the embodiment of the present application, a protruding first surface portion 91 is arranged at the position of the first area 7221 corresponding to the pole ear portion 72 for welding with the pole 2 or the adapter plate 5, so that when the ultrasonic pre-welding of the gathered portion 722 is performed, the protrusion of the first surface portion 91 and the area smaller than the total area of ​​the first welding surface 9 are utilized, so that the first surface portion 91 contacts the pole ear sheet 721 first, and the force application area is smaller, thereby increasing the local pressure. When the pre-welding pressure and energy remain unchanged, the pre-welding force is concentrated on the position of the first area 7221, thereby forming a first area 7221 with a relatively large degree of compaction, so that the first area 7221 is close to or becomes a solid plate structure.

[0138] For example, the original pressure was only 8 MPa, so that the pole piece could only undergo elastic deformation. After the ultrasonic welding head was removed, the air gap between the pole pieces would be restored, and only a few welds would be compacted. According to some embodiments of the present application, according to the pressure formula P=F / S, the pressure can be increased when the pre-welding pressure remains unchanged but the area is reduced, so that the pressure at the first surface 91 can be increased to about 30 MPa, so that the pole piece 721 can undergo plastic deformation, and basically no rebound will occur after the ultrasonic welding head 400 is removed, so that a plate structure with a relatively large degree of compaction can be formed.

[0139] In some embodiments, Fig.15As shown, the first face 91 is a convex curved surface. For example, the first face 91 is neither a plane nor a sharp folded surface. Therefore, compared with a plane, a convex curved surface can further reduce the area of ​​preferential contact, further increase the local pressure, and thus improve the compaction degree of pre-welding, and compared with a sharp folded surface, it can avoid the problem of sharp contact between the first face 91 and the pole tab 721, which causes the pole tab 721 to be fractured. In short, on the premise of improving the compaction degree of the first face 91 on the pole tab 721, it can play a role in protecting the pole tab 721, improve the welding yield, and improve the problems such as cracks in the pre-welding position.

[0140] In some embodiments, Fig.15 As shown, the cross section of the first face 91 is arc-shaped and the radius R1 is 0.2mm-0.5mm, that is, the cross section obtained by cutting the first face 91 through a plane perpendicular to the length direction of the first face 91 is the cross section, for example, the radius R1 can be 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, etc. Therefore, since the radius of the first face 91 is not too large, the first face 91 can have a certain protruding height when the width is constant, and since the radius of the first face 91 is not too small, the first face 91 can have a certain width when the protruding height is constant, so that the width and protruding height of the first face 91 can enable the first area 7221 to obtain a larger pre-welding pressure, achieve a better deep welding compaction effect, and enable the second area 7222 to achieve a shallow welding effect, so as to have a certain rigidity.

[0141] In some embodiments, Fig.15As shown, the connection between the first face portion 91 and the second face portion 92 is connected by a curved surface smooth transition. In this way, during the process of pre-welding the pole ear portion 72 by the ultrasonic horn 400, when the first welding surface 9 contacts the pole ear portion 72 and is subjected to reaction, since the connection between the first face portion 91 and the second face portion 92 is connected by a curved surface smooth transition, the stress concentration at the connection between the first face portion 91 and the second face portion 92 can be reduced, which causes the first welding surface 9 to crack at the junction of the first face portion 91 and the second face portion 92, thereby improving the reliability of the ultrasonic horn 400 pre-welding the pole ear portion 72, which is conducive to extending the service life of the ultrasonic horn 400. Therefore, according to the ultrasonic horn 400 of the embodiment of the present application, the structural reliability of the first welding surface 9 can be improved, and the structural stability of the ultrasonic horn 400 in the process of pre-welding the pole ear portion 72 can be improved, thereby improving the reliability of the ultrasonic horn 400 pre-welding the pole ear portion 72, which is conducive to extending the service life of the ultrasonic horn 400. For example, in some embodiments, the connection between the first surface 91 and the second surface 92 is smoothly connected by an arc surface, and the radius R2 of the arc surface can also be 0.2mm-0.5mm, such as 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, etc., thereby improving the smoothness of the transition connection.

[0142] In some embodiments, Fig.16 and Fig.17 As shown, the first face 91 is in the shape of an elongated strip and the first face 91 is provided in two parallel portions. Thus, the first region 7221 can be processed to be in the shape of an elongated strip and the first region 7221 is provided in two parallel portions. Thus, when welding the gathered portion 722 and the pole 2 or the adapter 5, the weld can extend along the length direction of the first region 7221, and the edges on both sides of the width of the weld can fall within the first regions 7221 on both sides, respectively, so that most of the edge 81 of the connecting portion 8 is not prone to cracks. Moreover, the portion of the second region 7222 of the pole tab 721 between the two first regions 7221 is easily deformed, meeting the welding shrinkage requirements and improving the problem of cracks on both sides of the width of the weld due to stress pulling. Moreover, the space of the gathering portion 722 can be fully utilized to increase the area and coverage of the first region 7221, which is beneficial to increase the length of the weld, thereby improving the reliability of the connection between the pole ear portion 72 and the pole 2 or the adapter plate 5, and facilitating the processing of the first region 7221 and the second region 7222, thereby reducing the processing difficulty of the gathering portion 722.

[0143] In some embodiments, Fig.15As shown, the protruding height H of the first face 91 relative to the second face 92 is 0.05mm-0.2mm. For example, 0.05mm, 0.1mm, 0.15mm, 0.2mm. As a result, the protruding height of the first face 91 is not too short, so that the first area 7221 can obtain a larger pre-welding pressure and achieve a better deep welding compaction effect, and the protruding height of the first face 91 is not too high, so that the second area 7222 can also obtain a pre-welding pressure and achieve a shallow welding effect, and can have a certain rigidity.

[0144] It should be noted that the surface shapes of the first face 91 and the second face 92 are not limited. For example, the surface of the first face 91 can be a diamond mesh surface or a spark erosion frosted surface, so that it can have a better deep welding effect. The surface of the second face 92 can be a spark erosion frosted surface, etc., so that it can have a better shallow welding effect.

[0145] like Figure 14-Figure 19 As shown, according to an embodiment of the present application, an ultrasonic welding device 2000 is also provided, comprising a welding seat 500 and an ultrasonic horn 400 according to any embodiment of the present application. During welding, a portion of the pole ear portion 72 can be placed on the welding seat 500, and the ultrasonic horn 400 is dropped, so that the stacked pole ear sheet 721 is sandwiched between the welding seat 500 and the ultrasonic horn 400, and the ultrasonic horn 400 can perform ultrasonic pre-welding on the pole ear portion 72.

[0146] In the above technical scheme, since the ultrasonic welding device 2000 includes the ultrasonic welding head 400 of any of the above schemes, it is beneficial to process the above-mentioned pole ear portion 72 having the first area 7221 and the second area 7222, which is beneficial to improve the problem of cracks on the edge of the connecting portion 8 between the pole ear portion 72 and the pole 2, improve the conductivity yield and connection strength of the position of the pole ear portion 72 for electrical connection with the pole 2, and improve the reliability of the battery cell 102.

[0147] It is worth noting that the welding surface of the welding seat 500 (referred to as the second welding surface 501) is not limited. For example, in some embodiments, the second welding surface 501 can be set to be close to or consistent with the first welding surface 9, such as the second welding surface 501 can include a third face and a fourth face, the third face protrudes from the fourth face, the third face is opposite to the first face 91, and the fourth face is opposite to the second face 92, so that the first area 7221 can obtain a better and greater degree of compaction effect relative to the second area 7222. For example, in some other embodiments, the second welding surface 501 can be set to a common uniform welding tooth shape, such as the second welding surface 501 as a whole is a diamond mesh surface or an electric spark erosion frosted surface, etc., so as to reduce production costs.

[0148] Next, an ultrasonic horn 400 according to a specific embodiment of the present application is described.

[0149] The welding surface of the ultrasonic welding head 400 is provided with a protrusion at the position of the edge 81 of the connection part 8 formed by welding the pole ear part 72 and the pole 2, so that when the pole ear part 72 is ultrasonically pre-welded to form the gathered part 722, the pre-welding force and energy can be concentrated on the local area to which the protrusion is directed, forming a deep welding area with a relatively large degree of compaction (i.e., the first area 7221), and the gathered part 722 is formed into a solid plate structure in the deep welding area. At the same time, the non-protruding part of the welding head contacts the pole ear piece 721 at the end during ultrasonic welding, and the pre-welding force is relatively small, forming a shallow welding area with a relatively small degree of compaction (i.e., the second area 7222), and the gathered part 722 is formed into a virtual welding layer structure in the shallow welding area. The shallow welding area can be used to reduce the stress of ultrasonic pre-welding and improve the problem of the pole ear piece 721 being torn. Subsequently, when laser welding is used to weld the gathered part 722 and the pole 2, at least part of the edge 81 of the connection part 8 falls in the deep welding area, which can effectively improve the problem of cracks on the edge 81 of the connection part 8. Furthermore, when the pole ear portion 72 is assembled with the pole post 2 , since the shallow welding area of ​​the pole ear portion 72 has a certain rigidity, it is convenient to penetrate and assemble the pole ear portion 72 into the pole post 2 .

[0150] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0151] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A battery cell, characterized in that: include: case; A pole, arranged on the housing; An electrode assembly comprises an active material coating portion disposed in the shell, and a pole ear portion electrically connecting the active material coating portion and the pole, wherein the pole ear portion comprises a plurality of pole ear sheets, the plurality of pole ear sheets are stacked and connected to form a gathered portion, the gathered portion has a first region and a second region, the degree of compaction of the plurality of pole ear sheets in the first region is greater than the degree of compaction in the second region, a connecting portion is formed at a position of the gathered portion for electrical connection with the pole, and at least a portion of an edge of the connecting portion on the gathered portion falls within the first region.

2. The battery cell according to claim 1, characterized in that: A portion of the edge of the connecting portion on the gathered portion falls within the second region.

3. The battery cell according to claim 2, characterized in that: A portion of the edge of the connecting portion on the surface of the gathered portion is a contour line, and the contour line includes a first line segment located in the first area and a second line segment located in the second area, and the length of the first line segment is greater than the length of the second line segment.

4. The battery cell according to claim 3, characterized in that: There are multiple first areas, adjacent first areas are separated by the second area, there are multiple first line segments arranged at intervals, multiple first line segments correspond to multiple first areas respectively, and adjacent first line segments are connected by the second line segments.

5. The battery cell according to claim 4, characterized in that: The contour line is a long ring, the first areas are two and are spaced apart along the width direction of the contour line, the first areas are formed as long strip areas extending along the length direction of the contour line, and the two long sides of the contour line fall on the two first areas respectively.

6. The battery cell according to claim 5, characterized in that: The width direction of the contour line is longitudinal, the longitudinal spacing between the two first areas is G0, the longitudinal width of the first area is W0, the connecting portion is a weld and the maximum longitudinal weld width is W1, the standard deviation of the maximum longitudinal weld width is [σ], and the longitudinal fluctuation value of the gathered portion assembly is ω; wherein, W1-3[σ]-ω≥G0, and W1+3[σ]+ω≤G0+2W0.

7. The battery cell according to any one of claims 1 to 6, characterized in that: The two first regions are arranged in parallel and symmetrically.

8. The battery cell according to any one of claims 1 to 7, characterized in that: The pole ear portion is formed into the gathered portion by ultrasonic welding, and the total area of ​​all the first regions is S less than or equal to the critical area S0; Where S0 = P × P is the pressure of compressed air input to the ultrasonic welding device; D is the cylinder diameter of the ultrasonic welding device, γ is the pressure ratio of the first area, [σ 0.2 ] is the yield strength of the pole piece, It is the residual strength coefficient of the pole piece under the action of welding heat.

9. The battery cell according to any one of claims 1 to 8, characterized in that: The first area is the area on the gathered portion where the degree of compaction is the greatest.

10. The battery cell according to any one of claims 1 to 9, characterized in that: The gathered portion is composed of the first area and the second area.

11. The battery cell according to any one of claims 1 to 10, characterized in that: The gathered portion is directly welded to the pole, so that the gathered portion and the pole together form the connecting portion.

12. The battery cell according to any one of claims 1 to 10, characterized in that: It also includes a transfer plate, through which the retracted portion is indirectly connected to the pole, and the retracted portion and the transfer plate are directly welded to form the connecting portion together.

13. The battery cell according to any one of claims 1 to 12, characterized in that: The pole comprises a pole body mounted on the housing, a receiving groove is formed on the pole body, and at least a part of the retracted portion is received in the receiving groove.

14. The battery cell according to claim 13, characterized in that: A accommodating cavity is formed in the shell, and the accommodating groove is open in a direction away from the accommodating cavity. A connecting hole is provided on the pole body, and the connecting hole passes through a groove wall on one side of the accommodating groove close to the accommodating cavity and connects the accommodating cavity and the accommodating groove, and the gathering portion is penetrated through the connecting hole.

15. The battery cell according to claim 14, characterized in that: The pole includes a pole cover plate which is covered on the pole body, and a liquid injection hole which can be communicated with the receiving groove is formed on the pole cover plate. The battery cell also includes a sealing structure for sealing the liquid injection hole.

16. A battery, characterized in that: The invention comprises a battery cell according to any one of claims 1 to 15.

17. An electrical device, characterized in that: Comprising a battery according to claim 16.

18. An ultrasonic welding head, characterized in that: For processing the gathered portion according to any one of claims 1 to 17, the welding surface of the ultrasonic welding head comprises a first face portion and a second face portion, the first face portion protrudes from the second face portion, the first face portion corresponds to processing the first region, and the second face portion corresponds to processing the second region.

19. The ultrasonic horn according to claim 18, characterized in that: The first surface portion is a convex curved surface.

20. The ultrasonic horn according to claim 19, characterized in that: The cross section of the first surface portion is arc-shaped and has a radius of 0.2 mm-0.5 mm.

21. The ultrasonic horn according to any one of claims 18 to 20, characterized in that: The connection between the first face portion and the second face portion is connected by a smooth transition of a curved surface.

22. The ultrasonic horn according to any one of claims 18 to 21, characterized in that: The first surface portion is in the shape of an elongated strip and there are two of the first surface portions which are arranged in parallel.

23. The ultrasonic horn according to any one of claims 18 to 22, characterized in that: The protrusion height of the first surface relative to the second surface is 0.05mm-0.2mm.

24. An ultrasonic welding device, characterized in that: It comprises a welding seat and an ultrasonic welding head according to any one of claims 18-23.

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