Battery cell, battery, electric device, ultrasonic welding horn, and ultrasonic welding device

Abstract

The application 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. 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. The plurality of tab pieces are stacked and connected to form a folding part. The folding part has a first region and a second region. The compaction degree of the plurality of tab pieces in the first region is greater than that in the second region. A connecting part is formed at a position of the folding part for electrically connecting with the pole. At least part of the edge of the connecting part on the folding part falls in the first region. The battery monomer can improve the problem of cracks on the edge of the connecting part, improve the electrical conductivity yield and connection strength of the tab part and the pole, and improve the reliability of the battery monomer.

Description

Technical Field

[0001] This 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 Technology

[0002] In recent years, new energy vehicles have experienced rapid development. In the field of electric vehicles, the power battery, as the power source, plays an irreplaceable and crucial role. The power battery comprises several individual battery cells; however, the reliability of these individual cells needs improvement. Summary of the Invention

[0003] This application provides 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, embodiments of this application provide a battery cell, including a housing, a terminal post, and an electrode assembly. The terminal post is disposed in the housing, and the electrode assembly includes an active material coating portion disposed within the housing, and a tab portion electrically connecting the active material coating portion and the terminal post. The tab portion includes a plurality of tab pieces, which are stacked and connected to form a converged portion. The converged portion has a first region and a second region. The plurality of tab pieces are compacted to a greater degree in the first region than in the second region. A connecting portion is formed at the position of the converged portion for electrical connection with the terminal post, and at least a portion of the edge of the connecting portion on the converged portion falls in the first region.

[0005] In the above technical solution, by setting multiple tabs to have a greater degree of compaction in the first region than in the second region, and by setting the connecting portion formed at the position of the gathered part for electrical connection with the terminal post to have at least a portion of the edge of the gathered part fall in the first region, so that at least a portion of the edge of the connecting portion is located in the relatively compacted area of ​​the gathered part, the problem of cracks appearing at the edge of the connecting portion can be improved, the conductivity and connection strength of the position of the tab for electrical connection with the terminal post can be improved, and the reliability of the battery cell can be improved.

[0006] Furthermore, by setting multiple tabs with a lower degree of compaction in the second region compared to the first region, and by making the multiple tabs slightly incompletely welded between the layers in the second region, the tensile stress at the connection between the first and second regions can be reduced through the deformation of the tabs in the slightly incompletely welded second region when welding to form the condensation section, and when welding the condensation section to the pole or adapter plate. This improves the problem of cracking of the tabs at the junction of the first and second regions. In addition, when welding the condensation section to the pole or adapter plate, the deformation of the tabs in the slightly incompletely welded second region can reduce the tension at the junction of the first region and the connection section, further reducing the problem of cracks appearing at the edge of the connection section.

[0007] In some embodiments, the edge of the connecting portion on the retractable portion partially falls into the second region.

[0008] In the above technical solution, since the multiple tabs are less compacted in the second region compared to the first region, the tabs are relatively easy to deform in the second region. When the welded closing part forms a connection with the pole or adapter piece, since the edge of the connection part on the closing part partially falls in the second region, the deformation of the tabs in the second region can be better utilized to meet the welding shrinkage requirements, reduce the tensile stress on the edge of the connection part, and further reduce the problem of cracks appearing on the edge of the connection part.

[0009] In some embodiments, the edge of the connecting portion on the surface of the retracting portion is a contour line, which includes a first line segment located in a first region and a second line segment located in a second region, wherein 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 outline falling in the first region is relatively larger than the portion falling in the second region, the portion of the edge of the connecting part falling in the first region can be relatively larger than the portion falling in the second region. This can more significantly reduce the cracks at the edge of the connecting part, improve the conductivity and connection strength of the position of the tab for electrical connection with the electrode post, and thus improve the reliability of the battery cell.

[0011] In some embodiments, there are multiple first regions, adjacent first regions are separated by second regions, and multiple first line segments are spaced apart, with each of the multiple first line segments corresponding to a multiple first regions, and adjacent first line segments are connected by second line segments.

[0012] In the above technical solution, the tabs in the second region, which are spaced between adjacent first regions, can more fully exert their deformation function, meet the welding shrinkage requirements, further reduce the tensile stress on the edge of the connection, and thus more significantly reduce the cracks on the edge of the connection, improve the conductivity and connection strength of the tab for electrical connection with the terminal post, and thus improve the reliability of the battery cell.

[0013] In some embodiments, the outline is a long ring, and there are two first regions that are spaced apart along the width direction of the outline. The first region is formed as an elongated strip-shaped region extending along the length direction of the outline, and the two long sides of the outline fall on the two first regions respectively.

[0014] In the above technical solution, the structure of the connecting part is simple and easy to form by laser welding, etc. Moreover, the number and distribution of the first region can make full use of the space of the storage part. When forming a strip-shaped connecting part, the first line segment is longer than the second line segment. The part of the edge of the connecting part that falls between the two first regions can more easily meet the welding shrinkage requirements through deformation. The part of the edge of the connecting part that falls in the first region is larger, so that the area that is not easy to form cracks is larger. This can significantly improve the conductivity and connection strength of the position of the tab for electrical connection with the terminal post, thereby improving the reliability of the battery cell.

[0015] In some embodiments, the width direction of the outline is longitudinal, the longitudinal distance between the two first regions is G0, the longitudinal width of the first region is W0, the connecting part is a weld with a maximum longitudinal weld width of W1, the standard deviation of the maximum longitudinal weld width is [σ], and the longitudinal fluctuation value of the assembly of the gathering part is ω; wherein, W1-3[σ]-ω≥G0, and W1+3[σ]+ω≤G0+2W0.

[0016] In the above technical solution, the two sides of the weld width can be reliably placed in the first region, so as to effectively reduce the cracks at the weld edge, improve the conductivity and connection strength of the position of the tab for electrical connection with the terminal post, and thus improve 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 gathering part can be fully utilized, increasing the area and coverage of the first region, and facilitating the separation of the second region from the first region, thereby simplifying the processing of the first and second regions and reducing the processing difficulty of the gathering part. Moreover, when welding the electrode lug to the gathering part, since the two first regions are arranged parallel and symmetrically, the ultrasonic welding head can weld along the length of the first region between the two first regions. This allows the edges of the weld width to easily fall on both sides of the first region, thereby reducing the welding difficulty and improving the welding efficiency.

[0019] In some embodiments, the tab portion is formed into a tapered portion by ultrasonic welding, and the total area of ​​the entire first region is S less than or equal to the critical area S0; wherein... P is the pressure of the compressed air input to the ultrasonic welding device; D is the cylinder diameter of the ultrasonic welding device; γ is the pressure percentage in the first region; [σ 0.2 [ ] represents the yield strength of the tab. This represents the residual strength coefficient of the electrode lugs under 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 tab under the action of welding heat softening, so that the tab can undergo better plastic deformation, and the first region can obtain a more effective compaction effect.

[0021] In some embodiments, the first region is the region on the gathered portion that has the highest degree of compaction.

[0022] In the above technical solution, at least a portion of the edge of the connection portion formed by the closing portion for electrical connection with the electrode post is set in the first region with the greatest compaction. This can more effectively improve the problem of cracks appearing at the edge of the weld, more effectively improve the conductivity and connection strength of the electrode tab for electrical connection with the electrode post, and thus improve the reliability of the battery cell.

[0023] In some embodiments, the retractable portion consists of a first region and a second region.

[0024] The above technical solution simplifies the structure and processing of the gathering part, reduces the processing difficulty of the gathering part, and improves the processing quality of the gathering part.

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

[0026] The above technical solution can improve the problem of cracks appearing at the edge of the first weld formed between the gathering part and the pole post, improve the conductivity and connection strength of the electrode tab and the pole post, and thus improve the reliability of the battery cell.

[0027] In some embodiments, the battery cell further includes an adapter plate, the folding portion is indirectly connected to the terminal post through the adapter plate, and the folding portion and the adapter plate are directly welded together to form a connection portion.

[0028] The above technical solution can improve the problem of cracks appearing at the edge of the second weld formed between the gathering part and the adapter piece, improve the conductivity and connection strength of the tab and the adapter piece, and thus improve the reliability of the battery cell.

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

[0030] In the above technical solution, by housing at least a portion of the gathering part in the receiving groove, the gathering part occupies at least a portion of the space in the receiving groove, thereby reducing the space occupied by the gathering part in the housing and saving space in the housing to accommodate a larger volume of active material coating part, which is beneficial to improving the energy density of the battery cell, or, if 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 receiving cavity is formed inside the housing, the receiving groove is open in the direction away from the receiving cavity, the pole body has a connecting hole, the connecting hole penetrates the groove wall of the receiving groove near the receiving cavity and connects the receiving cavity and the receiving groove, and the retractable part passes through the connecting hole.

[0032] In the above technical solution, when electrolyte is injected into a battery cell, the electrolyte can be injected into a receiving tank and then flow towards the receiving cavity through a connecting hole. The receiving tank acts as a buffer for the electrolyte, mitigating problems such as splashing and overflow. Furthermore, the sidewalls of the receiving tank can, to some extent, prevent electrolyte splashing, reducing external contamination and facilitating rapid electrolyte injection. Moreover, since there is no need to create a separate injection channel on the casing, no special processing of the casing is required, which helps reduce the structural complexity and manufacturing difficulty of the casing.

[0033] In some embodiments, the terminal post includes a terminal post cover plate covering the terminal post body, the terminal post cover plate having an injection hole that can communicate with a receiving groove, and the battery cell also includes a sealing structure for sealing the injection hole.

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

[0035] Secondly, embodiments of this application also provide a battery, including a battery cell of any of the above-described solutions.

[0036] In the above technical solution, the reliability of the battery cell according to the embodiment of this application is improved, which is beneficial to improving the performance of the battery.

[0037] Thirdly, embodiments of this application also provide an electrical device including a battery from any of the above-described solutions.

[0038] In the above technical solution, the improved battery performance is beneficial to enhancing the power consumption performance of the electrical device.

[0039] Fourthly, embodiments of this application also provide an ultrasonic welding head for processing the converging portion of any of the above-mentioned schemes. The welding surface of the ultrasonic welding head includes a first face and a second face, the first face protruding from the second face, the first face corresponding to the processing of a first region, and the second face corresponding to the processing of a second region.

[0040] In the above technical solution, during ultrasonic pre-welding of the closing portion, the protrusion of the first facet, with an area smaller than the total area of ​​the welding surface, allows the first facet to contact the electrode tab first, resulting in a smaller pressure area and thus increasing local pressure. With constant pre-welding pressure and energy, the pre-welding force is concentrated on the first region, forming a first region with a relatively high degree of compaction, making the first region approach or become a solid plate structure. In short, according to the ultrasonic welding head of this application embodiment, by setting the welding surface of the ultrasonic welding head to include a first facet and a second facet, with the first facet protruding from the second facet, the first region processed by the first facet can have a higher degree of compaction than the second region processed by the second facet.

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

[0042] In the above technical solution, compared to a flat first surface, the convex curved surface can further reduce the preferential contact area and further increase the local pressure, thereby improving the compaction degree of pre-welding. Furthermore, compared to a sharp, folded first surface, it can avoid sharp contact between the first surface and the tab, preventing the tab from being crushed. In short, it can protect the tab while increasing the compaction degree of the first surface on the tab, improving welding yield and mitigating problems such as cracks appearing at the pre-welding location.

[0043] In some embodiments, the cross-section of the first face is arc-shaped with a radius of 0.2 mm to 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 protrusion height when the width is fixed. And since the radius of the first face is not too small, the first face can have a certain width when the protrusion height is fixed. Thus, the width and protrusion height of the first face can enable the first area to obtain a large pre-welding pressure, achieve a good deep welding compaction effect, and enable the second area to achieve a shallow welding effect, so as to have a certain rigidity.

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

[0046] In the above technical solution, during the pre-welding of the electrode lug by the ultrasonic welding head, when the welding surface of the ultrasonic welding head contacts the electrode lug and is subjected to a reaction force, the connection between the first and second facets is smoothly transitioned via a curved surface. This reduces stress concentration at the connection between the first and second facets, preventing cracking of the welding surface at the junction of the first and second facets. This improves the reliability of the ultrasonic welding head's pre-welding of the electrode lug and helps extend the service life of the ultrasonic welding head. Therefore, the ultrasonic welding head according to the embodiments of this application can improve the structural reliability of the welding surface of the ultrasonic welding head and enhance the structural stability of the ultrasonic welding head during the pre-welding of the electrode lug, thereby improving the reliability of the ultrasonic welding head's pre-welding of the electrode lug and helping to extend the service life of the ultrasonic welding head.

[0047] In some embodiments, the first face is elongated and there are two first faces arranged in parallel.

[0048] In the above technical solution, the first region can be processed into an elongated shape, and there are two first regions arranged in parallel. This allows the weld to extend along the length of the first region when welding the convergence part to the pole or adapter plate. The two edges of the weld width can fall within the two first regions respectively, thus making it less prone to cracking at most of the weld edge. Furthermore, the portion of the electrode tab located in the second region between the two first regions is easily deformable, meeting welding shrinkage requirements and improving the problem of cracking at the two edges of the weld width due to stress tension. Moreover, the space of the convergence part can be fully utilized, increasing the area and coverage of the first region, which is beneficial for increasing the weld length, thereby improving the reliability of the connection between the electrode tab and the pole or adapter plate, and facilitating the processing of the first and second regions while reducing the processing difficulty of the convergence part.

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

[0050] In the above technical solution, the protrusion height of the first face is not too low, so that the first area can obtain a large pre-welding pressure and achieve a good deep welding compaction effect. In addition, the protrusion height of the first face is not too high, so that the second area can also obtain pre-welding pressure and achieve a shallow welding effect, thus having a certain rigidity.

[0051] Fifthly, embodiments of this application also provide an ultrasonic welding apparatus, including a welding base and an ultrasonic welding head according to any of the above-described embodiments.

[0052] In the above technical solution, since the ultrasonic welding device includes the ultrasonic welding head of any of the above solutions, it is beneficial to process the tab with the first region and the second region, thereby improving the problem of cracks appearing at the edge of the connection part formed at the position of the tab for electrical connection with the terminal post, improving the conductivity and connection strength of the position of the tab for electrical connection with the terminal post, and improving the reliability of the battery cell. Attached Figure Description

[0053] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0054] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments;

[0055] Figure 2 Exploded views of the battery structure provided in some embodiments of this application;

[0056] Figure 3 This is a schematic diagram of the structure of a battery cell provided in some embodiments of this application;

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

[0058] Figure 5 For along Figure 4 Sectional view of line AA in the middle;

[0059] Figure 6 for Figure 5 A magnified view of part B, shown in the center circle;

[0060] Figure 7 This is a schematic diagram showing the connection between the tab and the pole post provided in some embodiments of this application;

[0061] Figure 8 Exploded view of an electrode assembly and a cover plate with electrode posts provided in some embodiments of this application;

[0062] Figure 9 for Figure 8 A magnified view of part C, circled in the middle;

[0063] Figure 10 A schematic diagram showing the connection between an electrode assembly and a cover plate with electrode posts provided in some embodiments of this application;

[0064] Figure 11 for Figure 10A magnified view of part D, circled in the middle;

[0065] Figure 12 This is a schematic diagram illustrating the interaction between a battery cell and a busbar component according to some embodiments of this application;

[0066] Figure 13 A schematic diagram showing the connection between the electrode lug and the electrode post via an adapter piece in some embodiments of this application;

[0067] Figure 14 A schematic diagram showing the electrode tab being processed by an ultrasonic welding device according to some embodiments of this application;

[0068] Figure 15 for Figure 14 An enlarged view of the ultrasonic welding head shown;

[0069] Figure 16 This is a schematic diagram of the structure of an ultrasonic welding head provided in some embodiments of this application;

[0070] Figure 17 for Figure 16 A magnified view of part E, circled in the middle;

[0071] Figure 18 This is a schematic diagram of the structure of the welding socket provided in some embodiments of this application;

[0072] Figure 19 for Figure 18 A magnified view of part F shown in the middle circle.

[0073] Reference numerals: Vehicle 1000; First direction X; Second direction Y; Third direction Z; Battery 100; Controller 200; Motor 300; Housing 101; First housing body 1011; Second housing body 1012; Battery cell 102; Busbar component 103; Housing 1; Receiving cavity 11; Terminal 2; Terminal body 3; Receiving groove 36; Connecting hole 37; Terminal cover plate 4; Injection hole 43; Adapter piece 5; Sealing structure 6; First seal 61; Second seal Component 62; Electrode assembly 7; Active material coating part 71; Electrode tab part 72; Electrode tab plate 721; Gathering part 722; First region 7221; Second region 7222; Connecting part 8; Edge 81; Outline 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 part 91; Second face part 92; Welding seat 500; Second welding surface 501. Detailed Implementation

[0074] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0075] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0076] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0077] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0078] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

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

[0080] In this application, "multiple" means two or more (including two).

[0081] In this application, the battery cell 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 this application are not limited to these. The battery cell may be cylindrical, flat, cuboid, or other shapes, etc., and the embodiments of this application are not limited to these. Battery cells are generally divided into three types according to their packaging method: cylindrical battery cells, square battery cells, and pouch battery cells, and the embodiments of this application are not limited to these.

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

[0083] A battery cell includes a casing, electrode components, and electrolyte. The casing houses the electrode components and electrolyte. The casing contains at least one electrode component, which consists of a positive electrode, a negative electrode, and a separator. The electrode component can be a wound structure or a stacked structure, etc. The battery cell primarily functions by the movement of metal ions between the positive and negative electrode components.

[0084] A positive electrode typically includes a positive current collector and a positive active material layer. The positive active material layer is directly or indirectly coated onto the positive current collector. The positive current collector without a positive active material layer protrudes from the one with a positive active material layer, serving as the positive electrode tab. Taking a lithium-ion battery as an example, the material of the positive current collector can be aluminum, and the material of the positive active material layer can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc.

[0085] A negative electrode typically includes a negative current collector and a negative active material layer. The negative active material layer is directly or indirectly coated onto the negative current collector. The negative current collector without a negative active material layer protrudes from the negative current collector with a negative active material layer, and the negative current collector without a negative active material layer serves as the negative electrode tab. The material of the negative current collector can be copper, and the material of the negative active material layer can be carbon or silicon, etc.

[0086] To ensure that a large current can be passed without melting, multiple positive electrode tabs are stacked together to form the positive electrode tab section, and multiple negative electrode tabs are stacked together to form the negative electrode tab section. A terminal post is provided on the casing; the positive electrode tab section is electrically connected to the positive electrode terminal post, and the negative electrode tab section is electrically connected to the negative electrode terminal post.

[0087] In related technologies, multi-layered tabs are ultrasonically welded together to form a plate-shaped tab. This plate-shaped tab is then laser-welded onto the corresponding terminal post to achieve connection and electrical conductivity. However, ultrasonic welding typically uses a uniform weld head. Due to insufficient pressure and energy provided by the ultrasonic welding device, the uniform weld head cannot form a solid, fused plate; instead, it presents as a loosely welded plate of multiple foil layers. Therefore, when the tab is laser-welded to the terminal post, cracks appear at the edges of the laser weld, affecting the conductivity and connection strength between the tab and the terminal post, thus impacting the reliability of the battery cell.

[0088] Therefore, embodiments of this application propose a battery cell including a housing, a terminal post, and an electrode assembly. The terminal post is disposed in the housing, and the electrode assembly includes an active material coating portion disposed within the housing, and a tab portion connecting the active material coating portion and the terminal post. The tab portion includes multiple tab pieces, which are stacked and connected to form a converged portion. The converged portion has a first region and a second region. The multiple tab pieces are compacted to a greater degree in the first region than in the second region. The converged portion is connected to the terminal post to form a connecting portion, and at least a portion of the edge of the connecting portion on the converged portion falls in the first region.

[0089] Therefore, by setting multiple tabs with a greater degree of compaction in the first region compared to the second region, and ensuring that at least a portion of the edge of the connection formed by connecting the gathered portion and the terminal post falls within the first region, at least a portion of the edge of the connection is located within the relatively compacted area of ​​the gathered portion. This improves the problem of cracks appearing at the edge of the connection, increases the conductivity and connection strength between the tabs and the terminal post, and ultimately enhances the reliability of the battery cell. Furthermore, by setting multiple tabs with a lesser degree of compaction in the second region compared to the first region, and by slightly loosely soldering the tabs between the layers in the second region, the tensile stress at the connection between the first and second regions can be reduced through deformation of the tabs in the slightly loosely soldered second region during the welding of the gathered portion and the welding of the gathered portion to the terminal post. This improves the problem of cracking at the interface between the first and second regions. Additionally, during the welding of the gathered portion to the terminal post, the deformation of the tabs in the loosely soldered second region reduces the tensile stress at the interface between the first region and the connection, further reducing the problem of cracks appearing at the edge of the connection.

[0090] This application provides an electrical device that uses a battery as a power source. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0091] For ease of explanation, the following embodiments will be described using a vehicle 1000 as an example of an electrical device according to an embodiment of this application.

[0092] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of this application. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery 100 is disposed inside the vehicle 1000, and the battery 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery 100 can be used to power the vehicle 1000; for example, the battery 100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during startup, navigation, and driving.

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

[0094] Please refer to Figure 2 , Figure 2This is an exploded view of the structure of a battery 100 provided in some embodiments of this application. The battery 100 includes a housing 101 and a plurality of battery cells 102, the battery cells 102 being housed within the housing 101. The housing 101 provides assembly space for the battery cells 102, and the housing 101 can adopt various structures. In some embodiments, the housing 101 may include a first housing body 1011 and a second housing body 1012, the first housing body 1011 and the second housing body 1012 overlapping each other, and the first housing body 1011 and the second housing body 1012 together define an assembly space for accommodating the battery cells 102. The second box body 1012 can be a hollow structure open at one end, and the first box body 1011 can be a plate-like structure. 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 together define the assembly space. Alternatively, the first box body 1011 and the second box body 1012 can both be hollow structures open on one side, with the open side of the first box body 1011 covering the open side of the second box body 1012. Of course, the box 101 formed by the first box body 1011 and the second box body 1012 can be of various shapes, such as a cylinder, a cuboid, etc.

[0095] In battery 100, multiple battery cells 102 can be connected in series, parallel, or in a hybrid configuration. A hybrid configuration means that multiple battery cells 102 are connected in both series and parallel configurations. Multiple battery cells 102 can be directly connected in series, parallel, or in a hybrid configuration, and then the entire assembly of the multiple battery cells 102 is housed within housing 101. Alternatively, battery 100 can also be composed of multiple battery cells 102 first connected in series, parallel, or in a hybrid configuration to form a battery module, and then multiple battery modules are connected in series, parallel, or in a hybrid configuration to form a whole, which is also housed within housing 101. Battery 100 may also include other structures; for example, battery 100 may also include a busbar component for electrically welding multiple battery cells 102.

[0096] Each battery cell 102 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited to these. The battery cell 102 can be cylindrical, flat, cuboid, etc. For example, see reference... Figure 3 In the embodiment shown, 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 all perpendicular to each other.

[0097] In some embodiments of this application, such as Figures 4-6As shown, the battery cell 102 includes: a housing 1, a terminal post 2, and an electrode assembly 7. The terminal post 2 is disposed in the housing 1. The electrode assembly 7 includes an active material coating portion 71 disposed in the housing 1 and a tab portion 72 connected to the active material coating portion 71. The tab portion 72 is electrically connected to the terminal post 2. The "electrical connection" includes direct or indirect connection to achieve electrical conduction, that is, the tab portion 72 is directly or indirectly connected to the terminal post 2 to achieve electrical conduction.

[0098] Exemplarily, a receiving cavity 11 is formed inside the housing 1, the active material coating portion 71 is housed in the receiving cavity 11, the electrode post 2 passes through the housing 1, and the electrode tab 72 is welded to the electrode post 2. The electrode tab 72 and the electrode post 2 are directly electrically connected, so that the electrode tab 72 is electrically connected between the active material coating portion 71 and the electrode post 2. Alternatively, the electrode tab 72 and the electrode post 2 are indirectly connected via an adapter piece 5 (e.g., combined with...). Figure 13 For example, the tab 72 can be welded to one end of the adapter piece 5, and the other end of the adapter piece 5 can be welded to the pole piece 2. The tab 72 can be electrically connected to the pole piece 2 through the adapter piece 5.

[0099] Combination Figures 7-9 The tab portion 72 includes multiple tab pieces 721, which are stacked and connected to form a convergent portion 722. This means the multiple tab pieces 721 in the convergent portion 722 are not only stacked but also connected, for example, by welding. The convergent portion 722 has a first region 7221 and a second region 7222. The compaction degree of the multiple tab pieces 721 in the first region 7221 is greater than that in the second region 7222. In other words, the interlayer spacing of the multiple tab pieces 721 in the first region 7221 is smaller than that in the second region 7222. For example, the interlayer spacing in the first region 7221 can be zero, resulting in better compaction. It is worth noting that the "compaction degree" mentioned in this application refers to the tightness of the interlayer bonding of the multiple tab pieces 721. A larger interlayer gap results in a smaller compaction degree, and a smaller interlayer gap results in a larger compaction degree. The minimum interlayer gap can be zero, i.e., fused together, at which point the compaction degree is greatest.

[0100] For example, since the degree of compaction of the first region 7221 and the second region 7222 is different, the thickness of the gathering portion 722 in the first region 7221 and the second region 7222 is different. The plurality of tabs 721 are more compacted in the first region 7221 than in the second region 7222, and each tab 721 has a generally uniform thickness. As a result, 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 smaller than that in the second region 7222.

[0101] For example, the tab 72 is formed into a gathered portion 722 by ultrasonic welding. The first region 7221 is a deep welded region relative to the second region 7222, and the second region 7222 is a shallow welded region relative to the first region 7221. For example, the first region 7221 is formed into a solid plate-shaped compacted structure fused together, and the second region 7222 is formed into a layered, incomplete welded structure. It should be noted that when multiple tabs 721 are processed into a gathered portion 722 connected together, they are not limited to being formed by ultrasonic welding. For example, other methods can be used instead, such as molecular diffusion welding, resistance welding, etc.

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

[0103] For example, combined Figure 6 and Figure 7 The convergence portion 722 is directly welded to the terminal post 2 to form a connection portion 8 together. For example, the convergence portion 722 and the terminal post 2 are laser welded to form the connection portion 8, which is a laser weld, denoted as the first weld 80. The edge of the first weld 80 on the convergence portion 722 constitutes the edge 81 of the connection portion 8 on the convergence portion 722, and at least a portion of the edge of the first weld 80 is located within the first region 7221. It should be noted that the connection between the convergence portion 722 and the terminal post 2 is not limited to laser welding; other methods can also be used, 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 appearing at the edge of the first weld 80 can be improved, thereby increasing the conductivity and connection strength of the position of the tab 72 for electrical connection with the terminal post 2, and thus improving the reliability of the battery cell 102.

[0104] For example, combined Figure 13The retractable portion 722 is indirectly connected to the pole post 2 via the adapter piece 5. The retractable portion 722 and the adapter piece 5 are directly welded together to form the connecting portion 8. For example, the retractable portion 722 and the adapter piece 5 are laser welded to form the connecting portion 8. The connecting portion 8 is a laser weld, denoted as the second weld 85. The edge of the second weld 85 on the retractable portion 722 constitutes the edge 81 of the connecting portion 8 on the retractable portion 722. At least a portion of the edge of the second weld 85 is located in the first region 7221 of the retractable portion 722. It should be noted that the connection between the retractable portion 722 and the adapter piece 5 is not limited to laser welding. For example, other methods can be used, 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 appearing at the edge of the second weld 85 can be improved, the conductivity and connection strength of the tab 72 and the adapter 5 can be increased, thereby improving the reliability of the battery cell 102.

[0105] Therefore, by setting multiple tabs 721 with a greater degree of compaction in the first region 7221 than in the second region 7222, and by ensuring that at least a portion of the edge 81 of the connecting portion 8 formed by the closing portion 722 for electrical connection with the terminal post 2 falls on the first region 7221, at least a portion of the edge 81 of the connecting portion 8 is located in the relatively compacted area of ​​the closing portion 722, thereby improving the problem of cracks appearing on the edge 81 of the connecting portion 8, improving the conductivity and connection strength of the position of the tab 72 for electrical connection with the terminal post 2, and thus improving the reliability of the battery cell 102.

[0106] Furthermore, by setting multiple tabs 721 in the second region 7222 with a lower degree of compaction compared to the first region 7221, the multiple tabs 721 in the second region 7222 are slightly poorly welded. When welding to form the gathered part 722, and when welding the gathered part 722 to the pole post 2 or the adapter piece 5, the deformation of the tabs 721 in the second region 7222 with slightly poor welds can reduce the tensile stress at the connection between the first region 7221 and the second region 7222, thus improving the problem of cracking of the tabs 721 at the junction of the first region 7221 and the second region 7222. When welding the gathered part 722 to the pole post 2 or the adapter piece 5, the deformation of the tabs 721 in the second region 7222 with poor welds can reduce the tension at the junction of the first region 7221 and the weld, further reducing the problem of cracks appearing on the edge 81 of the connection part 8.

[0107] Furthermore, the gathered portion 722, formed by welding, such as ultrasonic welding, possesses a certain degree of rigidity in both the first region 7221 and the second region 7222, thereby facilitating the assembly of the tab 72. For example, when the pole post 2 has a connecting hole 37, and the tab 72 needs to pass through the connecting hole 37 before being welded to the pole post 2, the gathered portion 722's rigidity facilitates the tab 72's insertion into the connecting hole 37, improving the assembly efficiency of the tab 72 and reducing assembly difficulty.

[0108] Specifically, when the interlayer gaps of the multilayer tabs 721 are large, there are significant air gaps between the layers. When laser welding is performed at these locations with the electrode post 2, the welding heat is blocked by these large air gaps, causing the heat to remain in the air gaps for a longer period, which can easily burn off the tabs 721 and form cracks. However, in the embodiments of this application, since the multilayer tabs 721 in the first region 7221 are fused together and have a relatively compacted structure with smaller or no interlayer gaps, the heat from laser welding can be conducted more quickly in the first region 7221, thus improving the problem of heat remaining in a certain place for a long time, burning off the tabs 721 and forming cracks.

[0109] It is worth noting that in the embodiments of this application, the type of electrode post 2 is not limited; it can be a negative electrode post 2 or a positive electrode post 2. For example, the tab 72 welded to the negative electrode post 2 is a copper tab, and the tab 72 welded to the positive electrode post 2 is an aluminum tab. Aluminum has the characteristics of large shrinkage and poor fluidity after heating, while copper has the characteristics of small shrinkage and good fluidity after heating. Therefore, the positive electrode tab 72 is more prone to cracking after welding to the positive electrode post 2, while the negative electrode tab 72 is less prone to cracking after welding to the negative electrode post 2.

[0110] Therefore, at least the tab 72 of the positive electrode and the post 2 of the positive electrode can adopt the above-described improved scheme, in which "the tab 72 includes a plurality of tab pieces 721, the plurality of tab pieces 721 are stacked and connected to form a convergent portion 722, the convergent portion 722 has a first region 7221 and a second region 7222, the plurality of tab pieces 721 are more compacted in the first region 7221 than in the second region 7222, the convergent portion 722 is connected to the post 2 to form a connecting portion 8, and at least a portion of the edge 81 of the connecting portion 8 on the convergent portion 722 falls in the first region 7221". The tab 72 of the negative electrode and the post 2 of the negative electrode can adopt the above-described improved scheme, or they can choose not to.

[0111] In some embodiments of this application, the first region 7221 is the region with the highest degree of compaction on the gathering portion 722. Specifically, the gathering 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 gathering portion 722, is the first region 7221. Therefore, by placing at least a portion of the edge 81 of the connection portion 8 formed by the gathering portion 722 for electrical connection with the electrode post 2 on the gathering portion 722 in the first region 7221 with the highest degree of compaction, the problem of cracks appearing on the edge 81 of the connection portion 8 can be more effectively improved, the conductivity yield and connection strength of the position of the electrode tab 72 for electrical connection with the electrode post 2 can be more effectively improved, thereby improving the reliability of the battery cell 102.

[0112] It is worth noting that the number of regions divided by the gathering part 722 is unlimited, and the regions with different degrees of compaction are not limited to only having the first region 7221 and the second region 7222. For example, there may also be a third region, a fourth region, etc. When the first region 7221 is the region with the highest degree of compaction, the degree of compaction of the second region 7222 is not limited to the degree of compaction of other regions (such as the third region, the fourth region, etc.) other than the first region 7221.

[0113] In some embodiments, the gathering portion 722 may consist only of a first region 7221 and a second region 7222, but the number of the first region 7221 and the second region 7222 is not limited, and there may be at least one of each. That is, the gathering portion 722 consists of at least one first region 7221 and at least one second region 7222, which can simplify the structure and processing of the gathering portion 722, reduce the processing difficulty of the gathering portion 722, and improve the processing quality of the gathering portion 722.

[0114] In some embodiments of this application, combined with Figures 7-11 The edge 81 of the connecting portion 8 on the closing portion 722 partially falls into the second region 7222. That is, the edge 81 of the connecting portion 8 on the closing portion 722 does not fall entirely into the first region 7221; part of the edge 81 of the connecting portion 8 on the closing portion 722 falls into the first region 7221, and another part falls into the second region 7222. As a result, since the multiple tabs 721 are less compacted in the second region 7222 than in the first region 7221, the tabs 721 are relatively easy to deform in the second region 7222. When welding the closing portion 722 and the pole post 2 or the adapter piece 5 to form the connecting portion 8, since the edge 81 of the connecting portion 8 on the closing portion 722 partially falls into the second region 7222, the deformation of the tabs 721 in the second region 7222 can be better utilized, meeting the welding shrinkage requirements, reducing the tensile stress on the edge 81 of the connecting portion 8, and further reducing the problem of cracks appearing on the edge 81 of the connecting portion 8.

[0115] In some embodiments of this application, combined with Figure 11 The portion of the edge 81 of the connecting portion 8 on the surface of the converging portion 722 is a contour line 82. The contour line 82 includes a first line segment 821 located in the first region 7221 and a second line segment 822 located in the second region 7222. The length of the first line segment 821 is greater than the length of the second line segment 822. That is, the portion of the contour line 82 that falls in the first region 7221 is relatively larger than the portion that falls in the second region 7222. This allows the portion of the edge 81 of the connecting portion 8 that falls in the first region 7221 to be relatively larger than the portion that falls in the second region 7222. This can more significantly reduce cracks in the edge 81 of the connecting portion 8, improve the conductivity and connection strength of the position of the tab 72 for electrical connection with the terminal post 2, and thus improve the reliability of the battery cell 102.

[0116] In some embodiments of this application, combined with Figure 11 The first region 7221 consists of multiple regions, with adjacent first regions 7221 separated by a second region 7222. Multiple first segments 821 are spaced apart, each corresponding to one of the multiple first regions 7221. Adjacent first segments 821 are connected by second segments 822. Therefore, the tabs 721 in the second regions 7222, spaced between adjacent first regions 7221, can more fully utilize their deformation capacity, meeting welding shrinkage requirements and further reducing tensile stress on the edge 81 of the connecting portion 8. This significantly reduces cracks on the edge 81 of the connecting portion 8, improves the conductivity and connection strength of the tab 72 at the point of electrical connection with the terminal post 2, and ultimately enhances the reliability of the battery cell 102.

[0117] In some embodiments of this application, combined with Figure 11 The outline 82 is a long ring, meaning that the outline 82 is a ring and its length is greater than its width, such as a rectangle, an ellipse, a racetrack shape, etc. There are two first regions 7221, spaced apart along the width of the outline 82. The first region 7221 is formed as a long strip extending along the length of the outline 82, meaning that the length of the first region 7221 extends along the length of the outline 82. The two long sides of the outline 82 fall into the two first regions 7221 respectively, thus the long sides of the outline 82 constitute at least a portion of the first line segment 821, and at least a portion of the short sides of the outline 82 constitute the second line segment 822.

[0118] Therefore, the structure of the connecting part 8 is simple and easy to form by laser welding, etc. Moreover, the number and distribution of the first regions 7221 can make full use of the space of the storage part. When forming the strip-shaped connecting part 8, the first line segment 821 is longer than the second line segment 822. The part of the edge 81 of the connecting part 8 that falls between the two first regions 7221 can more easily meet the welding shrinkage requirements through deformation. The part of the edge 81 of the connecting part 8 that falls in the first region 7221 is larger, so that the area that is not easy to form cracks is larger. This can significantly improve the conductivity and connection strength of the position of the tab 72 for electrical connection with the pole post 2, thereby improving the reliability of the battery cell 102.

[0119] For example, such as Figure 11 As shown, the two first regions 7221 are arranged in parallel and symmetrically. This allows for full utilization of the space in the gathering portion 722, increasing the area and coverage of the first region 7221, and facilitating the separation of the second region 7222 from the two second regions 7222. This simplifies the processing of the first and second regions 7221 and reduces the processing difficulty of the gathering portion 722. Furthermore, when welding the electrode tab 72 to the gathering portion 722, the parallel and symmetrical arrangement of the two first regions 7221 allows the ultrasonic welding head 400 to weld along the length of the first region 7221 between the two regions. This ensures that the edges of the weld width easily fall within the first regions 7221 on both sides, reducing welding difficulty and improving welding efficiency.

[0120] In some embodiments of this application, such as Figure 11As shown, the width direction of the outline 82 is longitudinal, the longitudinal distance between the two first regions 7221 is G0, the longitudinal width of the first region 7221 is W0, the connecting part 8 is a weld (such as the first weld 80 or the second weld 85) 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 assembly of the gathering part 722 is ω (for example, the longitudinal fluctuation value generated by the assembly of the gathering part 722 with the pole post 2 or the adapter piece 5), for example, ω can be about 1mm; where W1-3[σ]-ω≥G0, and W1+3[σ]+ω≤G0+2W0. Thus, the two sides of the weld width can reliably fall on the first region 7221, so as to effectively reduce the cracks on the edge 81 of the connecting part 8, improve the conductivity and connection strength of the position of the electrode tab 72 for electrical connection with the pole post 2, and thus improve the reliability of the battery cell 102. Standard deviation, a mathematical term, is the square root of the arithmetic mean (i.e., variance) of the squared deviations from the mean, denoted by [σ]. It is also known as the experimental standard deviation and is most commonly used in probability and statistics as a measure of the degree of statistical distribution. According to engineering practice, the standard deviation [σ] is typically taken as three times the fluctuation.

[0121] In some embodiments of this application, the tab 72 is ultrasonically welded to form a tapered portion 722. The total area of ​​the entire first region 7221 is S less than or equal to the critical area S0, wherein... P is the pressure of the compressed air input to the ultrasonic welding device; D is the cylinder diameter of the ultrasonic welding device. Once the specific type of ultrasonic welding device is selected, the pressure of the compressed air input to the ultrasonic welding device and the cylinder diameter can be clearly defined. γ is the pressure percentage allocated to the first region 7221, that is, the proportion of the total input pressure allocated to the first region 7221 during ultrasonic welding by the ultrasonic welding device 2000, which can be taken as approximately 80%. [σ 0.2 [This refers to the yield strength of the tab 721.] The residual strength coefficient of the tab 721 under welding heat can be taken as approximately 40%. Among these, the yield strength [σ] of the tab 721... 0.2The strength at which the yield strength reaches 0.2% can be determined experimentally. For example, after the material type of the tab 721 is determined, the sample can be designed and tested according to "Metallic Materials - Tensile Testing" (GB / T 228.1-2010, GB / T 228.2-2015) (refer to GB / T228.1-2010 Metallic Materials - Tensile Testing - Part 1: Test Method at Room Temperature [S], Beijing: China Standards Press, 2011: 6-15; GB / T 228.2-2015 Metallic Materials - Tensile Testing - Part 2: Test Method at High Temperature [S]. Beijing: China Standards Press, 2015: 3-8).

[0122] For example, such as Figure 11 As shown, the first region 7221 is rectangular, and its area is the product of its length and width. For example, if the length of the first region 7221 is L0 and the width is W0, then the area of ​​the first region 7221 is L0 × W0. The total area of ​​the two first regions 7221 is S = 2L0 × W0. Therefore, the pressure of the first region 7221 during ultrasonic pre-welding can be greater than or equal to the yield strength of the tab 721 under the heat softening effect of welding. This allows the tab 721 to undergo better plastic deformation, resulting in a more effective compaction effect for the first region 7221.

[0123] In some embodiments of this application, such as Figure 6 As shown, the terminal post 2 includes a terminal post body 3 mounted on the housing 1. A receiving groove 36 is formed on the terminal post body 3, and at least a portion of the retractable portion 722 is housed in the receiving groove 36. Therefore, by housing at least a portion of the retractable portion 722 within the receiving groove 36, the space occupied by the retractable portion 722 within the receiving groove 36 is reduced. This saves space within the housing 1 to accommodate a larger volume of the active material coating portion 71, thereby improving the energy density of the battery cell 102, or, without changing the energy density of the battery cell 102, reducing its size.

[0124] In some embodiments of this application, such as Figure 5 and Figure 6As shown, a receiving cavity 11 is formed inside the housing 1, and a receiving groove 36 opens away from the receiving cavity 11. The electrode body 3 has a connecting hole 37, which penetrates the side wall of the receiving groove 36 near the receiving cavity 11 and connects the receiving cavity 11 and the receiving groove 36. A converging part 722 passes through the connecting hole 37. Thus, when electrolyte is injected into the battery cell 102, the electrolyte can be injected into the receiving groove 36 and then flow towards the receiving cavity 11 through the connecting hole 37. The receiving groove 36 can buffer the electrolyte to improve problems such as electrolyte splashing and overflow. Moreover, the side wall of the receiving groove 36 (i.e., the groove wall extending from the opening of the receiving groove 36 towards the receiving cavity 11) can block electrolyte splashing to a certain extent, reducing electrolyte contamination to the outside and facilitating rapid electrolyte injection. Furthermore, since there is no need to open a separate injection channel on the housing 1, no special processing is required for the housing 1, which helps to reduce the structural complexity and processing difficulty of the housing 1.

[0125] It is worth noting that there can be one or more connecting holes 37, and the gathering portion 722 can be provided through at least one of the connecting holes 37. For example, at least one connecting hole 37 can be filled with electrolyte. For instance, at least one connecting hole 37 is left unfilled (i.e., the gathering portion 722 is not provided), so that electrolyte can pass through without being obstructed by the gathering portion 722. Or, for instance, at least one connecting hole 37 can still be filled with electrolyte after the gathering portion 722 is provided.

[0126] In some embodiments, the retractable portion 722 is welded to the electrode post body 3 to form an electrical connection, thereby enabling the electrode assembly 7 to output electrodes from the electrode post body 3. Exemplarily, such as... Figure 6 As shown, when the receiving groove 36 is open in a direction away from the receiving cavity 11, the retractable part 722 is welded to the side wall of the receiving groove 36 near the receiving cavity 11, thereby improving the fit and facilitating the welding operation. Of course, this application is not limited to this. In other embodiments, the retractable part 722 can also 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 this application, such as Figure 6As shown, the terminal post 2 includes a terminal post cover plate 4 covering the terminal post body 3. The terminal post cover plate 4 has an injection hole 43 that communicates with the receiving cavity 36. The battery cell 102 also includes a sealing structure 6 for sealing the injection hole 43. Thus, when electrolyte needs to be injected into the battery cell 102, the sealing structure 6 is not installed at the injection hole 43, or the sealing structure 6 is in an open state, allowing electrolyte to be injected into the receiving cavity 36 through the injection hole 43. Furthermore, after injection, the sealing structure 6 can be installed at the injection hole 43, or the sealing structure 6 can be switched to a closed state, thereby sealing and closing the injection hole 43 to prevent electrolyte overflow and to prevent external foreign objects from entering the receiving cavity 11 from the injection hole 43, thereby improving the reliability of the battery cell 102. Therefore, by machining the liquid injection hole 43 on the terminal cover plate 4, the opening is relatively small and located on the outside, and the liquid injection inlet can be reliably sealed by the sealing structure 6, thereby improving the working reliability of the battery cell 102. Moreover, the sealing structure 6 can be designed in a flexible and diverse manner.

[0128] In some embodiments, such as Figure 6 As shown, the electrode cap 4 does not have a portion that stops the sealing structure 6 on the outside (i.e., the side away from the receiving cavity 11), so that the sealing structure 6 is suitable for installation onto the electrode cap 4 from the outside (i.e., the side away from the receiving cavity 11). Thus, by configuring the sealing structure 6 to be installed onto the electrode cap 4 from the outside to seal the injection hole 43, the sealing structure 6 can be installed after injection, ensuring the sealing of the injection hole 43. Furthermore, the installation position is close to the outside, facilitating quick assembly of the sealing structure 6. Moreover, the installation of the sealing structure 6 does not adversely affect the connection between the electrode body 3 and the electrode cap 4, ensuring the reliability of the connection between the electrode cap 4 and the electrode body 3.

[0129] The sealing structure 6 can be either detachable or fixed. For example, when the sealing structure 6 is detachable, it facilitates the maintenance of the injection port 43. For instance, when electrolyte needs to be added, the sealing structure 6 can be removed, the injection port 43 can be opened, and electrolyte can be injected into the receiving cavity 11 through the injection port 43. Afterward, the sealing structure 6 can be reinstalled. For example, the sealing structure 6 can be detachably connected to the electrode cover plate 4 by means of threads or screws, thus facilitating disassembly and assembly.

[0130] For example, when the sealing structure 6 is a non-removable fixed form, it can be fixed to the pole cap plate 4 by welding, riveting, or other methods, thereby improving the sealing reliability of the sealing structure 6 to the injection hole 43. For example, combined with Figure 6The injection hole 43 can be multi-segmented. The sealing structure 6 can include a first seal 61 that is interference-fitted with the injection hole 43, and a second seal 62 that covers the first seal 61 and is welded to the pole cap 4. Alternatively, in some embodiments, the second seal 62 can be detachably connected to the pole cap 4 by a screw-on mechanism to restrict the first seal 61 to the position where it is interference-fitted with the injection hole 43.

[0131] In some embodiments of this application, such as Figure 6 As shown, at least a portion of the sealing structure 6 is embedded within the injection hole 43. That is, the sealing structure 6 can be entirely embedded within the injection hole 43, or only a portion of it can be embedded within the injection hole 43. This allows for full utilization of the space within the injection hole 43, improving the sealing reliability of the sealing structure 6. Furthermore, it reduces the height of the sealing structure 6 protruding beyond the injection hole 43, minimizing its impact on the space outside the electrode cover plate 4. This helps reduce interference with the manifold component 103, increases the connection area between the manifold component 103 and the electrode cover plate 4, and improves flow efficiency.

[0132] It is worth noting that the position of the electrode post 2 on the housing 1 is not limited. For example, the housing 1 may include a body and a cover plate. The body defines a space open on one side, and the cover plate is located on the open side of the body to form a receiving cavity 11 between the body and the cover plate. In this case, the surface of the body opposite to the cover plate is the first housing wall, and the wall connecting the first housing wall and the cover plate is the second housing wall. In this case, the electrode post 2 can be located on the first housing wall, the second housing wall, or the cover plate. Furthermore, it should be noted that the positive electrode post 2 and the negative electrode post 2 can be located on the same side surface of the housing 1, or they can be located on different side surfaces of the housing 1. For example, the positive electrode post 2 and the negative electrode post 2 can be simultaneously located on the cover plate, or the positive electrode post 2 and the negative electrode post 2 can be simultaneously located on the first housing wall, or one of the positive electrode post 2 and the other is located on the cover plate, and the other is located on the first housing wall, and so on.

[0133] According to embodiments of this application, a battery 100 is also provided, including a battery cell 102 of any of the above-described embodiments. It is worth noting that the battery 100 according to embodiments of this application may or may not include a casing. Therefore, since the reliability of the battery cell 102 according to embodiments of this application is improved, it is beneficial to improve the performance of the battery 100.

[0134] For example, such as Figure 12As shown, the battery 100 may further include a busbar component 103, and multiple battery cells 102, with at least two connected electrically through the busbar component 103. This allows for the series connection and / or parallel connection of multiple battery cells 102. For example, when multiple battery cells 102 are connected in series, the anode terminal plate 4 of one battery cell 102 is connected to the cathode terminal plate 4 of the next battery cell 102 through a busbar component 103, while the cathode terminal plate 4 of the same battery cell 102 is connected to the anode terminal plate 4 of the previous battery cell 102 through another busbar component 103.

[0135] According to embodiments of this application, an electrical device is also provided, including a battery 100 of any of the above-described embodiments, the battery 100 being used to provide electrical energy to the electrical device. The electrical device can be any of the aforementioned devices or systems using the battery 100. Because the performance of the battery 100 is improved, it is beneficial to enhance the power consumption performance of the electrical device.

[0136] like Figures 14-17 As shown, according to an embodiment of this application, an ultrasonic welding head 400 is also provided for processing the tapered portion 722 of the tab portion 72 according to any embodiment of this application. The welding surface of the ultrasonic welding head 400 (denoted as the first welding surface 9) includes a first surface portion 91 and a second surface portion 92. The first surface portion 91 protrudes from the second surface portion 92. The first surface portion 91 is corresponding to the processing of the first region 7221, and the second surface portion 92 is corresponding to the processing of the second region 7222. Therefore, according to the ultrasonic welding head 400 of this application embodiment, by providing a first welding surface 9 including a first face 91 and a second face 92, and the first face 91 protruding from the second face 92, when the first face 91 protrudes from the second face 92, the first face 91 preferentially contacts the tab 721 relative to the second face 92 during ultrasonic pre-welding of the tab 72, and the second face 92 contacts the tab 721 relative to the first face 91. The pre-welding force is biased and concentrated on the part of the tab 72 that contacts the first face 91, so that the first region 7221 opposite to the first face 91 has a relatively large degree of compaction, thereby making the first region 7221 processed by the first face 91 have a larger degree of compaction than the second region 7222 processed by the second face 92.

[0137] Specifically, according to the ultrasonic welding head 400 of this application embodiment, a protruding first face 91 is provided at the position of the first region 7221 of the corresponding electrode tab 72 for welding with the electrode post 2 or the adapter piece 5. So when ultrasonically pre-welding the closing part 722, the first face 91 is protruding and its area is smaller than the total area of ​​the first welding surface 9, so that the first face 91 contacts the electrode tab 721 first, and the force application area is smaller, thereby increasing the local pressure. Under the condition that the pre-welding pressure and energy remain unchanged, the pre-welding force is concentrated on the position of the first region 7221, thereby forming a first region 7221 with a relatively large degree of compaction, so that the first region 7221 is close to or becomes a solid plate structure.

[0138] For example, the original pressure of only 8 MPa caused the tabs to undergo only elastic deformation. After the ultrasonic welding head was removed, the air gaps between the tabs would return, and only a few weld points would be compacted. However, according to some embodiments of this application, based on the pressure formula P = F / S, the pressure can be increased when the pre-welding pressure remains unchanged but the area is reduced. This allows the pressure at the first surface 91 to be increased to about 30 MPa, enabling the tabs 721 to undergo plastic deformation. After the ultrasonic welding head 400 is removed, there is basically no rebound, and a plate structure with a relatively large degree of compaction can be formed.

[0139] In some embodiments, such as Figure 15 As shown, the first facet 91 is a convex curved surface. For example, the first facet 91 is neither a plane nor a sharp fold. Therefore, compared to a plane, the convex curved surface can further reduce the preferential contact area, further increase the local pressure, and thus improve the compaction of the pre-weld. Compared to a sharp fold, it can avoid sharp contact between the first facet 91 and the tab 721, preventing the tab 721 from being crushed. In short, while increasing the compaction of the first facet 91 on the tab 721, it can also protect the tab 721, improve the welding yield, and mitigate problems such as cracks appearing at the pre-weld location.

[0140] In some embodiments, such as Figure 15As shown, the cross-section of the first face 91 is arc-shaped with a radius R1 of 0.2mm-0.5mm. That is, the cross-section is obtained by cutting the first face 91 with a plane perpendicular to its length direction. For example, the radius R1 can be 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, etc. Therefore, because the radius of the first face 91 is not too large, it can have a certain protrusion height while maintaining a certain width. And because the radius of the first face 91 is not too small, it can have a certain width while maintaining a certain protrusion height. This allows the width and protrusion height of the first face 91 to provide greater pre-welding pressure to the first region 7221, achieving a better deep weld compaction effect, and enabling the second region 7222 to achieve a shallow weld effect, thus possessing a certain rigidity.

[0141] In some embodiments, such as Figure 15 As shown, the connection between the first surface 91 and the second surface 92 is smoothly transitioned by a curved surface. Thus, during the pre-welding of the electrode tab 72 by the ultrasonic welding head 400, when the first welding surface 9 contacts the electrode tab 72 and is subjected to a reaction force, the smooth transition at the connection between the first surface 91 and the second surface 92 reduces stress concentration at the connection point, preventing cracking of the first welding surface 9 at the junction of the first surface 91 and the second surface 92. This improves the reliability of the ultrasonic welding head 400 in pre-welding the electrode tab 72 and helps extend the service life of the ultrasonic welding head 400. Therefore, the ultrasonic welding head 400 according to the embodiments of this application can improve the structural reliability of the first welding surface 9 and enhance the structural stability of the ultrasonic welding head 400 during the pre-welding of the electrode tab 72, thereby improving the reliability of the ultrasonic welding head 400 in pre-welding the electrode tab 72 and helping to extend the service life of the ultrasonic welding head 400. For example, in some embodiments, the connection between the first face 91 and the second face 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, such as Figure 16 and Figure 17As shown, the first facet 91 is elongated and there are two parallel first facets 91. Therefore, the first region 7221 can be machined into an elongated shape, and there are two parallel first regions 7221. Thus, when welding the converging part 722 to the pole post 2 or the adapter piece 5, the weld can extend along the length of the first region 7221, and the two edges of the weld width can fall within the two first regions 7221 respectively. This makes it less likely for most of the edge 81 of the connecting part 8 to crack. Furthermore, the portion of the pole piece 721 located in the second region 7222 between the two first regions 7221 is easily deformable, meeting the welding shrinkage requirements and improving the problem of cracks appearing on the two edges of the weld width due to stress tension. Moreover, the space of the gathering part 722 can be fully utilized to increase the area and coverage of the first region 7221, which is conducive to increasing the length of the weld, thereby improving the reliability of the connection between the electrode ear 72 and the electrode post 2 or the adapter piece 5, and facilitating the processing of the first region 7221 and the second region 7222, reducing the processing difficulty of the gathering part 722.

[0143] In some embodiments, such as Figure 15 As shown, the protrusion 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, and 0.2mm. Therefore, the protrusion height of the first face 91 is not too low, allowing the first region 7221 to obtain a greater pre-welding pressure, achieving a better deep weld compaction effect. Furthermore, the protrusion height of the first face 91 is not too high, allowing the second region 7222 to also obtain pre-welding pressure, achieving a shallow weld effect and possessing a certain degree of rigidity.

[0144] It should be noted that the surface shape of the first face 91 and the second face 92 is not limited. For example, the surface of the first face 91 can be a diamond-patterned surface or an electro-spark etched frosted surface, which can achieve a better deep soldering effect. The surface of the second face 92 can be an electro-spark etched frosted surface, etc., which can achieve a better shallow soldering effect.

[0145] like Figures 14-19 As shown, according to an embodiment of this application, an ultrasonic welding apparatus 2000 is also provided, including a welding base 500 and an ultrasonic welding head 400 according to any embodiment of this application. During welding, a portion of the electrode tab 72 can be placed on the welding base 500, and the ultrasonic welding head 400 is lowered, so that the stacked electrode tabs 721 are sandwiched between the welding base 500 and the ultrasonic welding head 400, and the ultrasonic welding head 400 can perform ultrasonic pre-welding on the electrode tab 72.

[0146] In the above technical solution, since the ultrasonic welding device 2000 includes the ultrasonic welding head 400 of any of the above solutions, it is beneficial to process the tab 72 with the first region 7221 and the second region 7222. This is beneficial to improve the problem of cracks appearing at the edge of the connection part 8 between the tab 72 and the pole post 2, improve the conductivity and connection strength of the position of the tab 72 for electrical connection with the pole post 2, and improve the reliability of the battery cell 102.

[0147] It is worth noting that the welding surface of the welding base 500 (denoted as the second welding surface 501) is not limited. For example, in some embodiments, the second welding surface 501 can be set to be similar to or consistent with the shape of the first welding surface 9. For instance, the second welding surface 501 may include a third face and a fourth face, with the third face protruding 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, thereby allowing the first region 7221 to achieve a better and greater compaction effect relative to the second region 7222. For example, in other embodiments, the second welding surface 501 can be set to a common uniform weld tooth shape, such as the second welding surface 501 being a diamond-patterned surface or an electro-spark etched frosted surface, thereby reducing production costs.

[0148] The ultrasonic welding head 400 according to a specific embodiment of the present application is described below.

[0149] The welding surface of the ultrasonic welding head 400 has a protrusion at the edge 81 of the connection portion 8 formed by welding the tab 72 and the pole post 2. This allows the pre-welding force and energy of the tab 72 to be concentrated locally on the protrusion during ultrasonic pre-welding to form the closing portion 722, creating a deep weld zone with relatively high compaction (i.e., the first region 7221). The closing portion 722 forms a solid plate structure in the deep weld zone. Simultaneously, the non-protruding part of the welding head contacts the tab 721 later during ultrasonic welding, resulting in a relatively smaller pre-welding force and a shallow weld zone with relatively low compaction (i.e., the second region 7222). The closing portion 722 forms a layered structure with a weak weld in the shallow weld zone. This shallow weld zone reduces the stress of ultrasonic pre-welding and improves the problem of the tab 721 being torn. Subsequently, when laser welding the closing portion 722 and the pole post 2 is used, at least a portion of the edge 81 of the connection portion 8 falls within the deep weld zone, effectively improving the problem of cracks appearing on the edge 81 of the connection portion 8. Furthermore, when assembling the tab 72 and the pole post 2, the shallow weld area of ​​the tab 72 has a certain rigidity, which facilitates the insertion and assembly of the tab 72 into the pole post 2.

[0150] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0151] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A battery cell, characterized in that, include: case; The pole post is disposed in the housing; An electrode assembly includes an active material coating portion disposed within the housing, and an electrode tab portion electrically connecting the active material coating portion and the electrode post. The electrode tab portion includes a plurality of tab pieces, which are stacked and connected to form a convergent portion. The convergent portion has a first region and a second region. The plurality of tab pieces are more compacted in the first region than in the second region. A connecting portion is formed at the position of the convergent portion for electrical connection with the electrode post. At least a portion of the edge of the connecting portion on the convergent portion falls within the first region.

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

3. The battery cell according to claim 2, characterized in that, The edge of the connecting part is a contour line on the surface of the gathering part. The contour line includes a first line segment located in the first region and a second line segment located in the second region. 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 regions, adjacent first regions are separated by second regions, and multiple first line segments are spaced apart. The multiple first line segments fall on the multiple first regions respectively, and adjacent first line segments are connected by second line segments.

5. The battery cell according to claim 4, characterized in that, The outline is a long ring, and the first region is two regions spaced apart along the width direction of the outline. The first region is formed as a long strip-shaped region extending along the length direction of the outline, and the two long sides of the outline fall on the two first regions respectively.

6. The battery cell according to claim 5, characterized in that, The width direction of the outline is longitudinal, the longitudinal distance between the two first regions is G0, the longitudinal width of the first region is W0, the connecting part is a weld with a maximum longitudinal weld width of W1, the standard deviation of the maximum longitudinal weld width is [σ], and the longitudinal fluctuation value of the assembly of the gathering part 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 1-6, characterized in that, The two first regions are arranged in parallel and symmetrically.

8. The battery cell according to any one of claims 1-7, characterized in that, The tab portion is formed by ultrasonic welding to form the folding portion, and the total area of ​​the entire first region is less than or equal to the critical area S0. Where, S0=P× P is the pressure of the compressed air input to the ultrasonic welding device; D is the cylinder diameter of the ultrasonic welding device; γ is the proportion of pressure applied in the first region; [σ 0.2 [ ] represents the yield strength of the tab. The residual strength coefficient of the electrode lug under welding heat.

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

10. The battery cell according to any one of claims 1-9, characterized in that, The gathering part consists of the first region and the second region.

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

12. The battery cell according to any one of claims 1-10, characterized in that, It also includes an adapter piece, through which the folding part is indirectly connected to the pole post, and the folding part is directly welded to the adapter piece so that the folding part and the adapter piece together form the connecting part.

13. The battery cell according to any one of claims 1-12, characterized in that, The pole includes a pole body installed on the housing, and a receiving groove is formed on the pole body, wherein at least a portion of the folding portion is received in the receiving groove.

14. The battery cell according to claim 13, characterized in that, The housing has a receiving cavity, the receiving groove is open in the direction away from the receiving cavity, the pole body has a connecting hole, the connecting hole penetrates the groove wall of the receiving groove near the receiving cavity and connects the receiving cavity and the receiving groove, and the folding part passes through the connecting hole.

15. The battery cell according to claim 14, characterized in that, The terminal post includes a terminal post cover plate covering the terminal post body, and an injection hole is formed on the terminal post cover plate that can communicate with the receiving groove. The battery cell also includes a sealing structure for sealing the injection hole.

16. A battery, characterized in that, Includes the battery cell according to any one of claims 1-15.

17. An electrical device, characterized in that, Includes the battery according to claim 16.

18. An ultrasonic welding head, characterized in that, For processing the gathering portion according to any one of claims 1-17, the welding surface of the ultrasonic welding head includes a first face and a second face, the first face protruding from the second face, the first face corresponding to the processing of the first region, and the second face corresponding to the processing of the second region.

19. The ultrasonic welding head according to claim 18, characterized in that, The first face is a convex curved surface.

20. The ultrasonic welding head according to claim 19, characterized in that, The cross-section of the first face is arc-shaped with a radius of 0.2mm-0.5mm.

21. The ultrasonic welding head according to any one of claims 18-20, characterized in that, The connection between the first face and the second face is made by a smooth transition through a curved surface.

22. The ultrasonic welding head according to any one of claims 18-21, characterized in that, The first face is elongated and there are two of them arranged in parallel.

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

24. An ultrasonic welding apparatus, characterized in that, Includes a welding socket and an ultrasonic welding head according to any one of claims 18-23.

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