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

Abstract

The application relates to the battery technical field and discloses a battery monomer, a battery device, a power utilization device and an ultrasonic welding device. The battery monomer comprises a shell, a pole and an electrode assembly. The pole is arranged in the shell, and the electrode assembly is accommodated in the shell and comprises a tab part. 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 at least one first region, at least one second region and at least one third region. The first region is connected with the third region through the second region. The compaction degree of the plurality of tab pieces in the first region is greater than that in the second region. The compaction degree of the plurality of tab pieces in the second region is greater than that in the third region. The folding part has a connecting part electrically connected with the pole. Part of the outer periphery of the connecting part is located in the first region. Part of the outer periphery of the connecting part is located in the second region. Therefore, the problem of cracks in the edge of the connecting part can be improved, and the reliability of the battery monomer is improved.

Description

Technical Field

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

[0002] In recent years, new energy vehicles have experienced rapid development. In the field of electric vehicles, power batteries, as the power source, play an irreplaceable and crucial role. Battery devices utilize individual battery cells to provide electrical energy, and the electrical connection between the tabs and terminals within a single battery cell significantly impacts its performance. Therefore, the reliability of individual battery cells needs further improvement. Summary of the Invention

[0003] This application provides a battery cell, a battery device, an electrical device, 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, comprising: a housing; a terminal post disposed in the housing; and an electrode assembly housed in the housing and including a tab portion, the tab portion including a plurality of tab pieces, the plurality of tab pieces being stacked and connected to form a converged portion, the converged portion having at least one first region, at least one second region, and at least one third region, the first region being connected to the third region through the second region, the plurality of tab pieces having a greater degree of compaction in the first region than in the second region, the plurality of tab pieces having a greater degree of compaction in the second region than in the third region, the thickness of the plurality of tab pieces in the first region and the thickness in the second region being both less than the stacking thickness of the plurality of tab pieces in the tab portion, a connecting portion being formed at a position of the converged portion for electrical connection with the terminal post, a portion of the outer periphery of the connecting portion on the converged portion being located in the first region, and a portion of the outer periphery of the connecting portion on the converged portion being located in the second region.

[0005] In the above technical solution, by setting the gathering part to have at least three different degrees of compaction, and separating the first region with a higher degree of compaction and the third region with a lower degree of compaction by the second region with a moderate degree of compaction, the interlayer gap in the second region is moderate compared to the first and third regions. The interlayer gap in the second region can achieve a good transition between the smaller interlayer gap in the first region and the larger interlayer gap in the third region. Therefore, when the gathering part is laser-welded with other components, it is beneficial to reduce the difference between the air gap obstruction encountered by the laser welding heat in the first region and the air gap obstruction encountered in the second region. The connecting part... With part of the outer periphery of the gathering section located in the first region and part in the second region, both the first and second regions with different degrees of compaction participate in the subsequent connection of the gathering section with other components, such as welding. This is beneficial to reduce the processing requirements and difficulty of the gathering section while achieving the connection between the gathering section and the electrode post. At the same time, it helps to improve the problem of thermal cracking at the junction of the outer edge of the connection section at the junction of the regions with different degrees of compaction, which is prone to occur because the regions with different degrees of compaction participate in the subsequent connection of the gathering section with other components. This improves the conductivity and connection strength of the electrode tab and the conductive part, and enhances the overcurrent capacity and reliability of the battery cell.

[0006] In some embodiments, a portion of the outer periphery of the connecting portion on the retractable portion is located in the third region.

[0007] In the above technical solution, by setting a portion of the outer periphery of the connecting part on the closing part in the third region, it is beneficial to reduce the setting requirements of the connecting part, and at the same time, it can improve the problem that cracks are easily generated on the outer periphery of the connecting part due to the large difference between the interlayer gap of the first region and the interlayer gap of the third region.

[0008] In some embodiments, the second region and the third region are respectively linear and both cooperate to pass through the opposite two sides of the connecting portion.

[0009] In the above technical solution, by setting the second and third regions to be linear, they can better adapt to the shape and distribution of the first region. Furthermore, the relatively small widths of both the second and third regions help increase the area of ​​the first region corresponding to the connection. For example, this ensures that the majority of the molten pool area of ​​the laser weld is within the first region, mitigating the problem of porosity in the weld pool and improving the current flow capacity at the connection. In addition, since the second and third regions penetrate the opposite edges of the connection, they effectively separate the first region, further balancing the stress distribution within it. This also helps optimize the current distribution within the connection, allowing for more uniform current flow throughout the entire connection, which improves the charge / discharge efficiency and cycle life of the battery cells.

[0010] In some embodiments, the total area of ​​the first region is greater than the total area of ​​the second region and greater than the total area of ​​the third region.

[0011] In the above technical solution, by setting the first region, the second region and the third region, the first region has the largest total area, which is conducive to increasing the area of ​​the first region corresponding to the connection part, so as to improve the problem of porosity in the weld pool and facilitate the improvement of the flow capacity at the connection part.

[0012] In some embodiments, the total area of ​​the first region is S1, and the sum of the total areas of the second region and the third region is S2, where S1:S2≤50.

[0013] In the above technical solution, by setting the ratio of the total area S1 of the first region to the sum of the total areas S2 of the second and third regions to be less than or equal to 50, it is beneficial to improve the problem that the welding device is difficult to separate from the gathering part due to the large total area of ​​the first region, and to improve the convenience of welding operation of the gathering part.

[0014] In some embodiments, 10 ≤ S1: S2 ≤ 25.

[0015] In the above technical solution, the ratio of the total area S1 of the first region to the sum of the total areas S2 of the second and third regions is further rationally set so that the total area of ​​the first region can take into account the flow capacity at the connection part, while also facilitating the separation of the welding device from the gathering part.

[0016] In some embodiments, there are multiple first regions, and the area of ​​a single first region accounts for more than or equal to 1 / 100 of the total area of ​​the first regions.

[0017] In the above technical solution, by setting the proportion of the area of ​​a single first region to the total area of ​​the first region, it is easier for the first region to provide a larger compaction area, which is beneficial to make more of the outer periphery of the connecting part on the closing part fall in the first region, thereby improving the welding quality.

[0018] In some embodiments, the area of ​​a single first region accounts for 1 / 5 to 1 / 20 of the total area of ​​the first regions; and / or, the number of the first regions is greater than or equal to 5.

[0019] In the above technical solution, by setting the proportion of the area of ​​a single first region to the total area of ​​the first region and the number of first regions, it is convenient for the first region to provide a larger and more suitable compaction area, which is conducive to further allowing more of the outer periphery of the connecting part on the closing part to fall into the first region, thus reducing the welding difficulty and improving the welding efficiency; at the same time, it does not place too high requirements on the structure of the welding device and the welding process, making it easy to implement.

[0020] In some embodiments, the first region is the region with the greatest compaction on the gathered portion, and the third region is the region with the least compaction on the gathered portion.

[0021] In the above technical solution, a portion of the outer periphery of the connecting part on the retracting part is located in the first region with the greatest compaction, which facilitates further improvement of the crack problem on the outer periphery of the connecting part, reduces cracks, and helps to further improve the electrical connection reliability between the retracting part and the pole.

[0022] In some embodiments, there are multiple second regions, and the multiple second regions have the same degree of compaction; or, at least two of the multiple second regions have different degrees of compaction.

[0023] In the above technical solution, by setting multiple second regions with the same degree of compaction, the three regions corresponding to the first, second, and third regions on the gathering part correspond to three different degrees of compaction, which is beneficial to simplifying the structure of the gathering part, simplifying the processing steps of the gathering part, and simplifying the structure of the device for processing the gathering part; and setting at least two of the multiple second regions with different degrees of compaction makes it easier to improve the structural flexibility of the gathering part and better meet actual needs.

[0024] In some embodiments, the folding portion is directly welded to the terminal post; or, the battery cell further includes an adapter piece, the folding portion is indirectly connected to the terminal post through the adapter piece, and the folding portion is directly welded to the adapter piece.

[0025] In the above technical solution, the folding part is directly welded to the pole post, or the folding part is indirectly connected to the pole post through an adapter piece. The connecting parts on the folding part are all used for welding to achieve electrical conduction between the folding part and the pole post. The setting is flexible, and the adapter piece can be selected as needed.

[0026] In some embodiments, there are multiple first regions, each formed into a strip shape. The multiple first regions are arranged in parallel and spaced apart. Two second regions are provided between two adjacent first regions, and a third region is provided between two second regions between two adjacent first regions.

[0027] In the above technical solution, the layout of the first, second, and third regions is relatively simple, which helps to simplify the structure of the welding device, simplify the welding process, and reduce the processing difficulty of the retractable part. At the same time, when welding the retractable part and the conductive part, the weld can extend along the length or width of the first region, and the two sides of the width or length of the weld can fall within the appropriate first region, which helps to increase the proportion of the outer periphery of the connection within the first region, making it less likely for most of the outer periphery of the connection to crack. Moreover, the part of the tab in the second region between the two first regions and the part in the third region between the two second regions are easily deformable, meeting the welding shrinkage requirements and improving the problem of cracks appearing at the edge of the weld due to stress tension.

[0028] In some embodiments, there are multiple first regions, and each first region is a quadrilateral. The outer periphery of the first region includes multiple side edges that are connected end to end in sequence. Each side edge of the first region is respectively connected to a second region. A third region is provided between two adjacent second regions.

[0029] In the above technical solution, the layout of the first region, the second region and the third region is also relatively simple, which is conducive to simplifying the structure of the welding device, simplifying the welding process and reducing the processing difficulty of the gathering part; at the same time, the part of the pole piece located in the second region between the two first regions and the part of the third region located between the two second regions are easy to deform, which meets the welding shrinkage requirements and improves the problem of cracks appearing on the edge of the weld due to stress tension.

[0030] In some embodiments, a plurality of the first regions are arranged in multiple rows and columns, and two adjacent first regions share a corresponding second region and a corresponding third region.

[0031] In the above technical solution, by setting two adjacent first regions to share the corresponding second region and the corresponding third region, it is beneficial to reduce the number of second and third regions, reduce the total area of ​​the second and third regions, and increase the area of ​​the first region corresponding to the connection part. For example, it is beneficial to make the area where the molten pool of the laser weld is located mostly the first region, which is beneficial to improve the problem of porosity in the weld molten pool and improve the flow capacity at the connection part.

[0032] Secondly, embodiments of this application provide a battery device including a single battery cell from any of the above embodiments.

[0033] In the above technical solution, the improved reliability of individual battery cells helps to improve the reliability of the battery device.

[0034] Thirdly, embodiments of this application provide an electrical device, including the battery device of any of the above embodiments.

[0035] In the above technical solution, the improved reliability of the battery device helps to improve the power consumption performance of the power-consuming device.

[0036] Fourthly, this application provides an ultrasonic welding apparatus for processing the gathering portion of any of the above embodiments. The ultrasonic welding apparatus includes a first welding structure and a second welding structure. The first welding structure is configured as a welding head, and the second welding structure is configured as a welding head or welding seat. The first welding structure includes a first body and a first welding tooth. The first welding tooth protrudes from the welding surface of the first body. The second welding structure includes a second body and a second welding tooth. The second welding tooth protrudes from the welding surface of the second body. The first welding tooth and the second welding tooth cooperate to process the first region. The first welding tooth and the second body cooperate to process the second region. The second welding tooth and the first body cooperate to process the second region. The first body and the second body cooperate to process the third region.

[0037] In the above technical solution, the ultrasonic welding device pre-welds the closing part. By utilizing the protruding arrangement of the first and second welding teeth, the first welding tooth contacts the electrode lug first during the welding of the first welding structure, and the second welding tooth contacts the electrode lug first during the welding of the second welding structure. This can increase the local pressure applied to the electrode lug at the first and second welding teeth. 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. Thus, the first and second welding teeth cooperate to form the first region with a relatively large degree of compaction. The first welding tooth and the second main body cooperate, and the second welding tooth and the first main body cooperate to process the second region with a medium degree of compaction. The first main body and the second main body cooperate to process the third region with a relatively small degree of compaction. The ultrasonic welding device has a simple structure and is easy to process the closing part.

[0038] In some embodiments, on the longitudinal section of the first weld tooth, the two sides of the width of the first weld tooth approach each other in a direction away from the first body, and the longitudinal section of the first weld tooth is perpendicular to the welding surface of the first body; on the longitudinal section of the second weld tooth, the two sides of the width of the second weld tooth approach each other in a direction away from the second body, and the longitudinal section of the second weld tooth is perpendicular to the welding surface of the second body.

[0039] In the above technical solution, when the first welding structure welds to the electrode lug, the end of the first welding tooth furthest from the first body preferentially contacts the electrode lug. This helps to reduce the area of ​​preferential contact of the first welding tooth, which in turn helps to increase the local pressure on the electrode lug and improve the compaction of the weld. At the same time, the width of the end of the first welding tooth furthest from the first body is less likely to form sharp corners, making it less likely for the first welding tooth to form sharp contact with the electrode lug, thus improving the situation where the electrode lug is easily cracked by the first welding tooth. It can be seen that the above-mentioned arrangement of the first welding tooth can improve the compaction of the electrode lug while providing a certain degree of protection for the electrode lug and improving the welding performance. Similarly, when the second welding structure welds to the electrode lug, the end of the second welding tooth furthest from the second body preferentially contacts the electrode lug. This helps to reduce the area of ​​preferential contact of the second welding tooth, which helps to increase the local pressure on the electrode lug and improve the compaction of the welding to the electrode lug. At the same time, the width of the end of the second welding tooth furthest from the second body is less likely to form sharp corners, making it less likely for the second welding tooth to form sharp contact with the electrode lug, thus improving the situation where the electrode lug is easily crushed by the second welding tooth. It can be seen that the above-mentioned arrangement of the second welding tooth can provide a certain degree of protection for the electrode lug while improving the compaction of the electrode lug and improving the welding yield.

[0040] In some embodiments, the longitudinal cross-sectional shape of both the first welding tooth and the second welding tooth is trapezoidal. In the above technical solution, by setting the longitudinal cross-sectional shapes of both the first and second welding teeth to be trapezoidal, the shapes of the first and second welding teeth are simple and easy to process. Simultaneously, it facilitates providing a relatively large and flat pressing surface for both the first and second welding teeth, and vice versa. This allows a portion of the first welding tooth to cooperate with a portion of the second welding tooth to process the first region, while another portion of the first welding tooth cooperates with the second body to process the second region, and another portion of the second welding tooth cooperates with the first body to process the second region.

[0041] In some embodiments, both the first welding tooth and the second welding tooth are formed in the shape of an elongated strip. There are multiple first welding teeth, which are arranged in parallel and spaced apart. There are also multiple second welding teeth, which are arranged in parallel and spaced apart.

[0042] In the above technical solution, the structure of the first welding tooth is similar to that of the second welding tooth, and the arrangement of the first welding tooth is the same as that of the second welding tooth, which facilitates the simplification of the first and second welding structures and helps to reduce design costs.

[0043] In some embodiments, the second welding structure is configured as a welding base, wherein the length direction of the first welding tooth is consistent with the length direction of the second welding tooth; or, the second welding structure is configured as a welding head, wherein the length direction of the first welding tooth intersects with or is consistent with the length direction of the second welding tooth.

[0044] In the above technical solution, when the second welding structure is configured as a welding base, it is convenient to form the first region, the second region and the third region by one welding, which simplifies the processing steps of the gathering part and helps to improve the production efficiency of the battery cell; when the second welding structure is configured as a welding head, the first region, the second region and the third region can be formed by two welding, which is relatively simple to operate. Attached Figure Description

[0045] 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.

[0046] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments;

[0047] Figure 2 Exploded views of the battery structure provided in some embodiments of this application;

[0048] Figure 3 Exploded views of a single battery cell provided in some embodiments of this application;

[0049] Figure 4 for Figure 3 The diagram shows the electrode assembly, with the diagonally marked sections corresponding to the tapered parts.

[0050] Figure 5 This is a schematic diagram of a retractable portion provided in some embodiments of this application. In the diagram, the portion marked with diagonal grid lines corresponds to the first region, the portion marked with diagonal lines corresponds to the second region, the blank portion corresponds to the third region, and the portion framed by dashed lines corresponds to the connecting portion.

[0051] Figure 6 This is a schematic diagram of a retractable portion provided in some embodiments of this application. In the diagram, the portion marked with diagonal grid lines corresponds to the first region, the portion marked with diagonal lines corresponds to the second region, the blank portion corresponds to the third region, and the portion framed by dashed lines corresponds to the connecting portion.

[0052] Figure 7 This is a schematic diagram of a retractable portion provided in some embodiments of this application. In the diagram, the blank area corresponds to the first region, the area with vertical lines corresponds to the second region, and the blackened area corresponds to the third region.

[0053] Figures 8a-8c Schematic diagrams of various structures of the adapter piece provided in some embodiments of this application;

[0054] Figures 9a-9bA schematic diagram of a first welding structure provided for some embodiments of this application;

[0055] Figures 10a-10b To and Figures 9a-9b A schematic diagram of the second welding structure that matches the first welding structure shown;

[0056] Figure 11 Schematic diagram of an ultrasonic welding apparatus provided in some embodiments of this application;

[0057] Figure 12 This is a welding schematic diagram of an ultrasonic welding apparatus provided in some embodiments of this application.

[0058] Figure label:

[0059] Electrical appliances 1000,

[0060] Battery device 100, controller 200, motor 300,

[0061] Battery cell 101, casing 102, first casing body 1021, second casing body 1022.

[0062] Casing 1, Body 11, Cover 12, Terminal Post 2

[0063] Electrode assembly 3, tab 31, tab plate 311, gathering part 312, first region 3121, second region 3122, third region 3123, connecting part 313, active material coating part 32.

[0064] Adapter 4

[0065] 400 ultrasonic welding device

[0066] First welded structure 5, first main body 51, first weld tooth 52.

[0067] Second welding structure 6, second main body 61, second welding tooth 62. Detailed Implementation

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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 the various components shown in the accompanying drawings in the embodiments of this application are merely illustrative and should not constitute any limitation on this application. The term "multiple" in this application refers to two or more (including two).

[0074] In this application, the battery cell may include lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-metal hydride batteries, nickel-cadmium batteries, lead-acid batteries, etc., and the embodiments of this application are not limited thereto. The battery cell may be cylindrical, flat, cuboid, or other shapes, and the embodiments of this application are not limited thereto.

[0075] The battery apparatus mentioned in the embodiments of this application can refer to an assembly of one or more battery cells for providing voltage and capacity. A battery cell assembly may include multiple battery cells connected in series, parallel, or mixed connections via a busbar. In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells.

[0076] As an example, a battery cell assembly can be a battery module, which consists of multiple battery cells arranged and fixed together to form a single module. As another example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0077] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cell assemblies housed within the housing. As an example, the individual battery cell assembly may be a battery pack, which can be housed within the housing by securing the battery pack to the housing. Alternatively, the individual battery cell assembly may be housed within the housing by directly securing multiple individual battery cells to the housing. The housing prevents liquids or other foreign matter from affecting the charging or discharging of the individual battery cells.

[0078] As an example, the enclosure may include a first enclosure and a second enclosure. The first enclosure and the second enclosure are fastened together to form a closed space inside the enclosure to house the individual battery cells; here, "closed" refers to covering or closing, which can be sealed or unsealed; the first enclosure may be a top cover or a bottom plate. As an example, the enclosure may include a top cover, a frame, and a bottom plate, with the top cover and bottom plate respectively connected to the frame to form a closed space inside the enclosure to house the individual battery cells.

[0079] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0080] A battery cell includes a casing, electrode assembly, and electrolyte. The casing houses the electrode assembly and electrolyte. The electrode assembly consists of a positive electrode, a negative electrode, and a separator. The battery cell primarily functions by the movement of metal ions between the positive and negative electrode plates. The positive electrode includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive current collector, while the uncoated positive current collector protrudes beyond it, serving as the positive electrode tab. Taking a lithium-ion battery as an example, the positive current collector can be made of aluminum, and the positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer. The negative electrode active material layer is coated on the surface of the negative electrode current collector, and the negative electrode current collector without the negative electrode active material layer protrudes from the negative electrode current collector with the negative electrode active material layer. The negative electrode current collector without the negative electrode active material layer serves as the negative electrode tab. The material of the negative electrode current collector can be copper, and the negative electrode active material can be carbon or silicon, etc.

[0081] To ensure that a large current can pass through without melting, the positive electrode has multiple tabs stacked together to form the positive electrode tab, which is electrically connected to the positive electrode post. Similarly, the negative electrode has multiple tabs stacked together to form the negative electrode tab, which is electrically connected to the negative electrode post.

[0082] The separator can be made of PP (polypropylene) or PE (polyethylene), etc. Furthermore, the electrode assembly can be a wound structure or a stacked structure; the embodiments of this application are not limited to these.

[0083] In recent years, new energy vehicles have experienced rapid development, and battery devices, as the power source of electric vehicles, play an irreplaceable and crucial role. Battery devices utilize individual battery cells to provide electrical energy, and the electrical connection between the tabs and terminals within a single battery cell has a significant impact on the cell's performance.

[0084] In related technologies, multi-layered tabs are ultrasonically welded together to form plate-shaped tabs. These plate-shaped tabs are then laser-welded directly or indirectly to the terminal posts to achieve electrical conductivity. However, the laser weld seam suffers from thermal cracking, which affects the conductivity yield and connection strength between the tabs and the terminal posts, ultimately impacting the reliability of the individual battery cells.

[0085] Analysis revealed that the aforementioned problem of hot cracking was particularly pronounced when the tabs were made of aluminum. This was partly due to the large shrinkage rate of aluminum during solidification, which caused the liquid metal at the tab-molten pool interface to neck. The interlayer gaps between multiple tabs prevented the liquid metal from filling the gaps, making it easy for the laser weld edges to crack.

[0086] Based on the above considerations, embodiments of this application propose a battery cell, which includes a housing, a terminal post, and an electrode assembly. The terminal post is disposed in the housing, and the electrode assembly is housed in the housing and includes a tab portion. The tab portion includes multiple tab pieces, which are stacked and connected to form a converged portion. The converged portion has at least one first region, at least one second region, and at least one third region. The first region is connected to the third region through the second region. The compaction degree of the multiple tab pieces in the first region is greater than that in the second region, and the compaction degree of the multiple tab pieces in the second region is greater than that in the third region. The thickness of the multiple tab pieces in the first region and the thickness in the second region are both less than the stacking thickness of the multiple tab pieces in the tab portion. A connection portion is formed at the position of the converged portion for electrical connection with the terminal post. A portion of the outer periphery of the connection portion on the converged portion is located in the first region, and a portion of the outer periphery of the connection portion on the converged portion is located in the second region.

[0087] Therefore, by setting the closing section to have at least three different degrees of compaction, and separating the first region with a higher degree of compaction and the third region with a lower degree of compaction by the second region with a moderate degree of compaction, the interlayer gap in the second region is moderate compared to the first and third regions. This interlayer gap in the second region allows for a smooth transition between the smaller interlayer gap in the first region and the larger interlayer gap in the third region. Consequently, when the closing section is laser-welded with other components, it helps to reduce the difference in welding heat between the air gap obstruction in the first region and the air gap obstruction in the second region. Furthermore, the connection section, during the closing... With part of the outer periphery of the part located in the first region and part in the second region, both the first and second regions with different degrees of compaction participate in the subsequent connection of the gathering part with other components, such as welding. This is beneficial to reduce the processing requirements and difficulty of the gathering part while achieving the connection between the gathering part and the electrode post. At the same time, it helps to improve the problem of thermal cracking at the junction of the outer edge of the connection part at the junction of the regions with different degrees of compaction, which is prone to occur because the regions with different degrees of compaction participate in the subsequent connection of the gathering part with other components. This improves the conductivity and connection strength of the electrode tab and the conductive part, and enhances the overcurrent capacity and reliability of the battery cell.

[0088] The battery device disclosed in this application can be used, but is not limited to, in electrical devices such as vehicles, ships, or aircraft. A power system incorporating the battery device disclosed in this application can be used to construct such an electrical device.

[0089] 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.

[0090] For ease of explanation, the following embodiments use a vehicle as an example to illustrate an electrical device 1000 according to an embodiment of this application. Please refer to... Figure 1 , Figure 1 The electrical device 1000 provided in some embodiments of this application is a structural schematic diagram of a vehicle. The vehicle can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery device 100 is installed inside the vehicle, and the battery device 100 can be located at the bottom, front, or rear of the vehicle. The battery device 100 can be used to power the vehicle; for example, the battery device 100 can serve as the vehicle's operating power source. The vehicle may also include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle during starting, navigation, and driving.

[0091] In some embodiments of this application, the battery device 100 can not only serve as the operating power source for the vehicle, but also as the driving power source for the vehicle, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle.

[0092] Please refer to Figure 2 , Figure 2This is an exploded view of the structure of a battery device 100 provided in some embodiments of this application. The battery device 100 includes a housing 102 and a plurality of battery cells 101, which are housed within the housing 102. The housing 102 provides assembly space for the battery cells 101, and the housing 102 can adopt various structures. In some embodiments, the housing 102 may include a first housing body 1021 and a second housing body 1022, which overlap each other, and the first housing body 1021 and the second housing body 1022 together define an assembly space for accommodating the battery cells 101. The second box body 1022 can be a hollow structure open at one end, and the first box body 1021 can be a plate-like structure. The first box body 1021 covers the open side of the second box body 1022 so that the first box body 1021 and the second box body 1022 together define the assembly space. Alternatively, the first box body 1021 and the second box body 1022 can both be hollow structures open on one side, with the open side of the first box body 1021 covering the open side of the second box body 1022. Of course, the box 102 formed by the first box body 1021 and the second box body 1022 can be of various shapes, such as a cylinder, a cuboid, etc.

[0093] In the battery device 100, multiple battery cells 101 can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells 101 are connected in both series and parallel configurations. Multiple battery cells 101 can be directly connected in series, parallel, or in a mixed configuration, and then the entire assembly of the multiple battery cells 101 is housed within a housing 102. Alternatively, the battery device 100 can also consist of multiple battery cells 101 first connected in series, parallel, or in a mixed configuration to form battery modules, and then these battery modules are connected in series, parallel, or in a mixed configuration to form a whole, which is then housed within the housing 102. The battery device 100 may also include other structures; for example, it may include a busbar component for electrical connection between the multiple battery cells 101.

[0094] Please refer to Figure 2 , Figure 2 The image shows an exploded view of the battery device 100 provided in some embodiments of this application. The battery device 100 includes multiple rows of battery cells 101, arranged along the length of a housing 102, with each row including multiple battery cells 101 arranged along the width of the housing 102; or, the multiple rows of battery cells 101 are arranged along the width of the housing 102, with each row including multiple battery cells 101 arranged along the length of the housing 102. Of course, the arrangement of the battery cells 101 is not limited to these arrangements.

[0095] Each battery cell 101 can be a secondary battery or a primary battery. A secondary battery refers to a battery cell 101 that can be recharged after discharge to activate its active materials and continue to be used. It can also be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and this application embodiment is not limited in this regard. The battery cell 101 can be cylindrical, flat, cuboid, or other shapes. For example, in... Figure 2 In the middle, the shape of the battery cell 101 is a cuboid.

[0096] Please refer to Figure 3 In the embodiments of this application, the battery cell 101 includes a housing 1, a terminal post 2, and an electrode assembly 3. The terminal post 2 is disposed in the housing 1, the electrode assembly 3 is housed in the housing 1, and the electrode assembly 3 includes a tab 31, which is electrically connected to the terminal post 2. It can be understood that the tab 31 can be directly connected to the terminal post 2 to achieve electrical conduction, or the tab 31 can be indirectly connected to the terminal post 2 through other components (such as the adapter piece 4 described later) to achieve electrical conduction.

[0097] For example, the housing 1 has a receiving cavity, and the electrode assembly 3 may also include an active material coating part 32, which is connected to the tab part 31. The housing 1 has a mounting hole, and the electrode post 2 passes through the mounting hole. As an example, the tab part 31 is welded to the electrode post 2 so that the tab part 31 and the electrode post 2 are directly electrically connected. In this case, the tab part 31 is electrically connected between the active material coating part 32 and the electrode post 2. As an example, the tab part 31 is indirectly fixed to the electrode post 2 through an adapter piece 4. For example, the tab part 31 can be welded to one end of the adapter piece 4, and the other end of the adapter piece 4 can be welded to the electrode post 2.

[0098] Please combine Figure 4 and Figure 12 The tab portion 31 includes a plurality of tab pieces 311. The plurality of tab pieces 311 are stacked and connected to form a gathering portion 312. The gathering portion 312 is formed on the overlapping part of the plurality of tab pieces 311, and the plurality of tab pieces 311 are connected to the position corresponding to the gathering portion 312. In other words, the plurality of tab pieces 311 in the gathering portion 312 not only have a stacked arrangement relationship, but also have a connection relationship. For example, the plurality of tab pieces 311 in the gathering portion 312 can be welded together.

[0099] The gathering portion 312 has at least one first region 3121, at least one second region 3122, and at least one third region 3123. The compaction degree of the plurality of tabs 311 in the first region 3121 is greater than that in the second region 3122, and the compaction degree of the plurality of tabs 311 in the second region 3122 is greater than that in the third region 3123. Therefore, the interlayer gap of the plurality of tabs 311 in the first region 3121 is smaller than that in the second region 3122, and the interlayer gap of the plurality of tabs 311 in the second region 3122 is smaller than that in the third region 3123. The thickness of the plurality of tabs 311 in the first region 3121 is less than the thickness of the plurality of tabs 311 in the second region 3122 and less than the thickness of the plurality of tabs 311 in the third region 3123.

[0100] The "compaction degree" mentioned in this application refers to the tightness of the interlayer bonding of the multilayer tabs 311. The larger the interlayer gap, the smaller the compaction degree; the smaller the interlayer gap, the larger the compaction degree and the smaller the thickness. The minimum interlayer gap can be zero, that is, fused into one piece, at which point the compaction degree is the maximum. It can be seen that the compaction degree of the second region 3122 is between the compaction degree of the first region 3121 and the compaction degree of the third region 3123. Therefore, the interlayer gap of the second region 3122 is also between the interlayer gap of the first region 3121 and the interlayer gap of the third region 3123.

[0101] In this context, the thickness of multiple tabs 311 in the first region 3121 is less than the stacked thickness of multiple tabs 311 in the tab portion 31. Similarly, the thickness of multiple tabs 311 in the second region 3122 is less than the stacked thickness of multiple tabs 311 in the tab portion 31. Therefore, the thickness of multiple tabs 311 in both the first and second regions 3121 is less than the theoretical thickness T of the tab portion 31. Taking the first region 3121 as an example, the fact that the thickness of multiple tabs 311 in the first region 3121 is less than the stacked thickness of the tab portion 31 indicates that the tabs 311 in the first region 3121 are compressed, yielded, and undergo plastic deformation. This reduces the thickness of the tabs 311 and causes the multiple layers of tabs 311 in the first region 3121 to be tightly bonded together with relatively small interlayer gaps. This allows the first region 3121 to form a compacted region with a compaction rate greater than 0%. Likewise, the second region 3122 is also a compacted region.

[0102] For example, the "compaction rate" of the first region 3121 refers to the ratio of the theoretical thickness of the tab 31 to the difference between the thickness T1 of the multiple tabs 311 in the first region 3121 and the theoretical thickness T of the tab 31, i.e., (T-T1) / T. The theoretical thickness T refers to the stacking thickness of the multiple tabs 311 in the tab 31 before connection, i.e., the thickness of the tabs 311 before compression and multiple layers without gaps. For example, if the thickness of a single tab 311 is a (i.e., a is the thickness of a single layer of foil), and b layers of tabs 311 are stacked in the tab 31 (i.e., b is the number of foil layers), then the stacking thickness of the multiple tabs 311 in the tab 31 before connection is a×b, therefore the theoretical thickness T of the tab 31 is a×b. For example, the thickness T1 of the plurality of tabs 311 in the first region 3121 can be the average thickness of the first region 3121 or the maximum thickness of the first region 3121; similarly, the thickness T2 of the plurality of tabs 311 in the first region 3121 can be the average thickness of the second region 3122 or the maximum thickness of the second region 3122, and the thickness T3 of the plurality of tabs 311 in the third region 3123 can be the average thickness of the third region 3123 or the maximum thickness of the third region 3123.

[0103] It is understandable that the third region 3123 can be a compacted region, that is, the thickness of the multiple tabs 311 in the third region 3123 is less than the stacking thickness of the multiple tabs 311 in the tab portion 31; or, the third region 3123 can also be a loose region, in which case the thickness of the multiple tabs 311 in the third region 3123 can be greater than or equal to the theoretical thickness T of the tab portion 31, and the multiple tabs 311 in the loose region are not effectively fused together, and there are interlayer gaps between the multiple tabs 311.

[0104] Optionally, multiple tabs 311 are welded together to form a convergence portion 312. The convergence portion 312 can be configured to form the first region 3121, the second region 3122, and the third region 3123 through a single welding operation, or the convergence portion 312 can be configured to form the first region 3121, the second region 3122, and the third region 3123 through multiple welding operations. For example, if the convergence portion 312 is configured to form the first region 3121, the second region 3122, and the third region 3123 through multiple welding operations, the convergence portion 312 is configured to form the first region 3121, the second region 3122, and the third region 3123 in the final welding operation.

[0105] For example, the tab portion 31 is formed into a gathering portion 312 by ultrasonic welding. For example, the first region 3121 is formed into a solid plate-shaped compacted structure fused together, and the second region 3122 is formed into a layered incomplete weld structure. Of course, the way to form the gathering portion 312 is not limited to this. For example, it can also be formed by resistance welding or other methods.

[0106] Recombined Figure 5 and Figure 6 The position of the retractable portion 312 for electrical connection with the pole post 2 forms a connecting portion 313. A portion of the outer periphery of the connecting portion 313 on the retractable portion 312 is located in the first region 3121, and a portion of the outer periphery of the connecting portion 313 is located in the second region 3122. The first region 3121 is connected to the third region 3123 through the second region 3122. Thus, the outer periphery of the first region 3121 is not directly connected to the outer periphery of the third region 3123, or in other words, the first region 3121 and the third region 3123 are separated by the second region 3122.

[0107] For example, the retractable portion 312 is directly welded to the terminal post 2, and the retractable portion 312 and the terminal post 2 together define the connecting portion 313. For example, the retractable portion 312 and the terminal post 2 are laser welded to form the connecting portion 313, which is a laser weld. In this case, the connecting portion 313 is referred to as the first weld. The outer periphery of the first weld on the retractable portion 312 is the outer periphery of the connecting portion 313 on the retractable portion 312. A portion of the outer periphery of the first weld is located in the first region 3121, and a portion of the outer periphery of the first weld is located in the second region 3122. Of course, the retractable portion 312 and the terminal post 2 can also form the connecting portion 313 by other means, such as arc welding. Since the first region 3121 is in a compacted state relative to the second region 3122, the problem of cracks appearing at the edge of the first weld can be improved, thereby improving the conductivity and connection strength of the position of the tab 31 for electrical connection with the terminal post 2, and thus improving the reliability of the battery cell 101.

[0108] For example, the battery cell 101 also includes an adapter piece 4. The folding portion 312 is indirectly connected to the terminal post 2 through the adapter piece 4. The folding portion 312 and the adapter piece 4 are directly welded so that the folding portion 312 and the adapter piece 4 together define the connecting portion 313. For example, the folding portion 312 and the adapter piece 4 are laser welded to form the connecting portion 313. The connecting portion 313 is a laser weld. In this case, the connecting portion 313 is referred to as the second weld. The outer periphery of the second weld on the folding portion 312 is the outer periphery of the connecting portion 313 on the folding portion 312. A portion of the outer periphery of the second weld is located in the first region 3121, and a portion of the outer periphery of the second weld is located in the second region 3122. Of course, the folding portion 312 and the adapter piece 4 can also form the connecting portion 313 by other means, such as arc welding. Since the first region 3121 is in a compacted state relative to the second region 312, the problem of cracks appearing at the edge of the second weld can be improved, the conductivity and connection strength of the tab 31 and the adapter 4 can be increased, and the reliability of the battery cell 101 can be improved.

[0109] For the sake of simplicity, the retractable portion 312 is connected to the conductive portion to form a connecting portion 313. The conductive portion can be a terminal post 2 or an adapter piece 4. Optionally, the retractable portion 312 and the conductive portion are laser welded. The laser welding can be spiral welding, and a straight-line root pass pre-welding can be used to improve the welding quality. The laser weld can include a main weld line and a root pass weld line. Four spiral welds can be performed within 1 second, but it is not limited to this.

[0110] It is understandable that forming a continuous and large area with a relatively high degree of compaction on the gathering part 312 is difficult to achieve in terms of processing. Moreover, if the entire gathering part 312 is processed into an area with a relatively high degree of compaction, for example, by welding the entire gathering part 312 into an area with a relatively high degree of compaction through ultrasonic welding, it is easy for the ultrasonic welding head to stick to the gathering part 312, making it difficult to separate the ultrasonic welding head from the gathering part 312, resulting in poor manufacturability. Therefore, the gathering part 312 usually has multiple areas with different degrees of compaction, and retains areas with relatively low degrees of compaction. When welding the gathering part 312 to other components, it is difficult to ensure that areas with completely identical degrees of compaction are used to achieve welding with the other components.

[0111] Therefore, by setting the gathering part 312 to have at least three different compaction degrees, and separating the first region 3121 with a higher compaction degree and the third region 3123 with a lower compaction degree from the second region 3122 with a moderate compaction degree, the interlayer gap of the multilayer tabs 311 in the second region 3122 is not significantly different from that in the first region 3121 compared to the third region 3123. In other words, the interlayer gap of the second region 3122 is moderate compared to the first region 3121 and the third region 3123. The interlayer gap of the second region 3122 can achieve a good transition between the smaller interlayer gap of the first region 3121 and the larger interlayer gap of the third region 3123. This helps to reduce laser laser damage when the gathering part 312 is laser welded to other components. The difference in welding heat between the air gap obstruction in the first region 3121 and the air gap obstruction in the second region 3122, and the fact that part of the outer periphery of the connecting part 313 on the closing part 312 is located in the first region 3121 and part in the second region 3122, means that both the first region 3121 and the second region 3122 with different compaction degrees participate in the subsequent connection of the closing part 312 with other components, such as welding. This is beneficial to reduce the processing requirements and processing difficulty of the closing part 312 while achieving the connection between the closing part 312 and the pole post 2. At the same time, it is beneficial to improve the problem that thermal cracks may easily appear at the junction of the connecting part 313 at the junction of the regions with different compaction degrees because the regions with different compaction degrees all participate in the subsequent connection of the closing part 312 with other components.

[0112] Of course, a portion of the outer periphery of the connecting part 313 on the closing part 312 is located in the first region 3121 with a greater degree of compaction. The interlayer gap of the multilayer tab 311 in the first region 3121 is small or there is no interlayer gap. During laser welding, the heat is not easily blocked by the large air gap and can be conducted quickly in the first region 3121. It is not easy for the tab 311 to burn out and form thermal cracks due to heat remaining in the air gap for a long time. Therefore, setting a portion of the outer periphery of the connecting part 313 on the closing part 312 in the first region 3121 is beneficial to improve the problem of thermal cracks on the outer periphery of the connecting part 313, thereby improving the conductivity and connection strength of the electrical connection between the tab 31 and the electrode post 2, and thus improving the reliability of the battery cell 101.

[0113] Furthermore, by setting the compaction degree of multiple tabs 311 in the second region 3122 to be less than that in the first region 3121, the multiple tabs 311 exhibit slight interlayer insufficiency in the second region 3122, and the insufficiency degree of the multiple tabs 311 is greater in the third region 3123. When welding to form the convergence portion 312, and when welding the convergence portion 312 to the pole post 2 or the adapter piece 4, the deformation of the tabs 311 in the insufficiency of the second region 3122 and the third region 3123 can reduce the first The tensile stress at the connection between region 3121 and the second region 3122 helps to further mitigate the cracking problem of the tab 311 at the junction of the first region 3121 and the second region 3122. Furthermore, when welding the convergence portion 312 to the pole post 2 or the adapter piece 4, the deformation of the tab 311 in the second region 3122 and the third region 3123, which are partially welded, reduces the tensile stress at the junction of the first region 3121 and the weld, further reducing the problem of cracks appearing on the outer periphery of the connection portion 313. It can be understood that the arrangement of the second region 3122 and the third region 3123 helps to balance the stress distribution in the first region 3121, facilitating the dispersion and reduction of stress concentration generated in the first region 3121, and improving the problem of cracks and stress concentration in the tab 31 caused by compaction.

[0114] 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 electrode tab 31 welded to the negative electrode post 2 is a copper electrode tab, and the electrode tab 31 welded to the positive electrode post 2 is an aluminum electrode tab. Aluminum has the characteristics of large shrinkage and poor fluidity after being heated, while copper has the characteristics of small shrinkage and good fluidity after being heated. Therefore, after the positive electrode tab 31 is welded to the positive electrode post 2, it is more likely to crack, while the negative electrode tab 31 is less likely to crack after being welded to the negative electrode post 2.

[0115] Therefore, at least the tab 31 of the positive electrode and the electrode post 2 of the positive electrode can adopt the above-described "tab 31 includes a plurality of tab pieces 311, the plurality of tab pieces 311 are stacked and connected to form a gathering portion 312, the gathering portion 312 has at least one first region 3121, at least one second region 3122 and at least one third region 3123, the first region 3121 is connected to the third region 3123 through the second region 3122, the compaction degree of the plurality of tab pieces 311 in the first region 3121 is greater than the compaction degree in the second region 3122, the plurality of tab pieces 311 in the second region 3123 are more compacted than the second region 3122, the plurality of tab pieces 311 in the second region 3122 are more compacted than the second region 3123 ... The compaction degree of region 3122 is greater than that of the third region 3123. The thickness of the plurality of tabs 311 in the first region 3121 and the thickness in the second region 3122 are both less than the stacking thickness of the plurality of tabs 311 in the tab portion 31. A connecting portion 313 is formed at the position of the gathering portion 312 for electrical connection with the pole post 2. A portion of the outer periphery of the connecting portion 313 on the gathering portion 312 is located in the first region 3121, and a portion of the outer periphery of the connecting portion 313 on the gathering portion 312 is located in the second region 3122. The tab portion 31 of the negative electrode and the pole post 2 of the negative electrode may or may not adopt the above-described improved solution.

[0116] Please refer to Figures 5-7 In some embodiments, a portion of the outer periphery of the connecting portion 313 on the closing portion 312 is located in the third region 3123. That is, the outer periphery of the connecting portion 313 on the closing portion 312 is located in the first region 3121, the second region 3122, and the third region 3123. In this case, the portion of the outer periphery of the connecting portion 313 located in the first region 3121 and the portion located in the third region 3123 are separated by the portion located in the second region 3122. This can improve the problem that cracks are easily generated on the outer periphery of the connecting portion 313 due to the large difference between the interlayer gaps in the first region 3121 and the third region 3123.

[0117] Of course, in other embodiments of this application, the connecting portion 313 may also be configured such that the outer periphery of the connecting portion 313 on the gathering portion 312 is located in the first region 3121 and the second region 3122, but not in the third region 3123, in which case the third region 3123 may be a compacted region.

[0118] Please refer to Figures 5-7In some embodiments, the second region 3122 and the third region 3123 are respectively linear, and the second region 3122 and the third region 3123 cooperate to penetrate the opposite side edges of the connecting portion 313. It can be understood that the cooperation of the second region 3122 and the third region 3123 to penetrate the opposite side edges of the connecting portion 313 may include each of the second region 3122 and the third region 3123 penetrating the opposite side edges of the connecting portion 313, or the region formed by the second region 3122 and the third region 3123 penetrating the opposite side edges of the connecting portion 313.

[0119] In the above technical solution, by setting the second region 3122 and the third region 3123 to be linear, the second region 3122 and the third region 3123 can better adapt to the shape and distribution of the first region 3121. Moreover, the widths of the second region 3122 and the third region 3123 are relatively small, which helps to increase the area of ​​the first region 3121 corresponding to the connecting part 313. For example, it makes it easier to make the area where the molten pool of the laser weld is mostly the first region 3121, which helps to improve the problem of porosity in the weld pool and improves the current flow capacity at the connecting part 313. In addition, since the second region 3122 and the third region 3123 respectively penetrate the opposite two sides of the connecting part 313, it is easy to separate the first region 3121, so as to further balance the stress distribution of the first region 3121, and it is also beneficial to optimize the current distribution in the connecting part 313, so that the current flows more evenly through the entire connecting part 313, which helps to improve the charging and discharging efficiency and cycle life of the battery cell 101.

[0120] Optionally, the first region 3121 and the second region 3122 can continuously penetrate the opposite two sides of the connecting portion 313 along a straight line or curve. For example, if the connecting portion 313 is rectangular, the first region 3121 and the second region 3122 can respectively penetrate the opposite two sides of the connecting portion 313 in the length direction and / or penetrate the opposite two sides of the connecting portion 313 in the width direction.

[0121] Please refer to Figures 5-7 In some embodiments, the total area of ​​the first region 3121 is greater than the total area of ​​the second region 3122, and the total area of ​​the first region 3121 is greater than the total area of ​​the third region 3123.

[0122] It can be understood that the total area of ​​the first region 3121 can be the sum of the areas of all the first regions 3121, the total area of ​​the second region 3122 can be the sum of the areas of all the second regions 3122, and the total area of ​​the third region 3123 can be the sum of the areas of all the third regions 3123. For example, if the areas of multiple first regions 3121 are equal, then the total area of ​​the first region 3121 is the area of ​​a single first region 3121 multiplied by the number of first regions 3121.

[0123] In the above technical solution, by setting the first region 3121, the second region 3122 and the third region 3123, the first region 3121 has the largest total area, which is conducive to increasing the area of ​​the first region 3121 corresponding to the connection part 313, so as to improve the problem of porosity in the weld pool and facilitate the improvement of the flow capacity at the connection part 313.

[0124] In some embodiments, the total area of ​​the first region 3121 is S1, and the sum of the total areas of the second region 3122 and the third region 3123 is S2, where S1:S2≤50.

[0125] In the above technical solution, by setting the ratio of the total area S1 of the first region 3121 to the sum of the total areas S2 of the second region 3122 and the third region 3123 to be less than or equal to 50, it is beneficial to improve the problem that the welding device is difficult to separate from the gathering part 312 due to the excessive total area of ​​the first region 3121, and to improve the welding operation convenience of the gathering part 312.

[0126] For example, S1:S2 can be 5, 10, 15, 20, 25, 30, 35, 40, 45 or 50, etc.

[0127] Furthermore, 10≤S1:S2≤25. Therefore, the ratio of the total area S1 of the first region 3121 to the sum of the total areas S2 of the second region 3122 and the third region 3123 is further rationally set so that the total area of ​​the first region 3121 can take into account the flow capacity at the connecting part 313, while also facilitating the separation of the welding device from the gathering part 312.

[0128] In some embodiments, there are multiple first regions 3121, and the area of ​​a single first region 3121 accounts for more than or equal to 1 / 100 of the total area of ​​the first regions 3121.

[0129] In the above technical solution, by setting the area of ​​a single first region 3121 to the proportion of the total area of ​​the first region 3121, the first region 3121 can provide a larger compaction area, which is beneficial to make more of the outer periphery of the connecting part 313 on the gathering part 312 fall on the first region 3121, thereby improving the welding quality.

[0130] For example, the area of ​​a single first region 3121 is 0.01, 0.03, 0.07, 0.12, 0.15, 0.18, 0.22, 0.25, or 0.3 of the total area of ​​the first region 3121.

[0131] Furthermore, the area of ​​a single first region 3121 accounts for 1 / 5 to 1 / 20 of the total area of ​​the first regions 3121; and / or, the number of first regions 3121 is greater than or equal to 5.

[0132] In the above technical solution, by setting the proportion of the area of ​​a single first region 3121 to the total area of ​​the first region 3121 and the number of first regions 3121, it is convenient for the first region 3121 to provide a larger and more suitable compaction area. This is beneficial to further ensure that more of the outer periphery of the connecting part 313 on the gathering part 312 falls on the first region 3121, which helps to reduce welding difficulty and improve welding efficiency. At the same time, it does not impose excessive requirements on the structure of the welding device and the welding process, making it easy to implement.

[0133] For example, the area of ​​a single first region 3121 is 0.05, 0.08, 0.1, 0.13, 0.16, 0.19 or 0.2 of the total area of ​​the first region 3121; the number of first regions 3121 can be 5, 7, 8, 10, 13, 15, 18 or 20.

[0134] In some embodiments, the first region 3121 is the region with the greatest compaction on the gathering portion 312, and the third region 3123 is the region with the least compaction on the gathering portion 312.

[0135] It is understood that the gathering part 312 may have multiple regions with different degrees of compaction. The first region 3121 has the greatest degree of compaction, the smallest interlayer gap, and the smallest thickness of the multiple tabs 311 in the first region 3121. The third region 3123 has the smallest degree of compaction, the largest interlayer gap, and the largest thickness of the multiple tabs 311 in the third region 3123.

[0136] In the above technical solution, a portion of the outer periphery of the connecting part 313 on the gathering part 312 is located in the first region 3121 with the greatest degree of compaction. This facilitates further improvement of the crack problem on the outer periphery of the connecting part 313, reduces cracks, and helps to further improve the electrical connection reliability between the gathering part 312 and the pole post 2.

[0137] Please refer to Figures 5-7In some embodiments, the gathering part 312 may consist only of a first region 3121, a second region 3122, and a third region 3123. The number of the three regions 3121, 3122, and 3123 is not specifically limited, which facilitates the flexible division of the regions of the gathering part 312 and the reasonable layout of the three regions. This helps to reduce the processing difficulty of the gathering part 312 and improve the processing quality and convenience of the gathering part 312.

[0138] Please refer to Figures 5-7 In some embodiments, there are multiple second regions 3122, and the multiple second regions 3122 have the same degree of compaction.

[0139] In the above technical solution, by setting multiple second regions 3122 with the same degree of compaction, the three regions 3121, 3122, and 3123 on the gathering part 312 correspond to three different degrees of compaction. This simplifies the structure of the gathering part 312, the processing steps of the gathering part 312, and the structure of the device for processing the gathering part 312. For example, when the gathering part 312 is formed by ultrasonic welding, it simplifies the structure of the ultrasonic welding device 400, especially the structure of the ultrasonic welding head and / or welding base. Moreover, when multiple second regions 3122 have the same degree of compaction, as an example, the first region 3121, the second region 3122, and the third region 3123 can be formed simultaneously by one welding operation, which further simplifies the processing steps.

[0140] Of course, when there are multiple second regions 3122, at least two of the multiple second regions 3122 can have different degrees of compaction. In this case, the gathering part 312 corresponds to at least four different degrees of compaction, which facilitates the improvement of the structural flexibility of the gathering part 312 and can better meet actual needs. Optionally, when the multiple second regions 3122 have different degrees of compaction, the first region 3121, the second region 3122 and the third region 3123 can be formed by multiple welding processes.

[0141] Please refer to Figure 5 In some embodiments, there are multiple first regions 3121, each formed into an elongated strip. These multiple first regions 3121 are parallel and spaced apart, meaning their length directions are parallel. Two second regions 3122 are provided between two adjacent first regions 3121, and a third region 3123 is provided between the two second regions 3122 between two adjacent first regions 3121. Therefore, each first region 3121 and each third region 3123 are separated by a second region 3122.

[0142] In the above technical solution, the layout of the first region 3121, the second region 3122, and the third region 3123 is relatively simple, which is conducive to simplifying the structure of the welding device, simplifying the welding process, and reducing the processing difficulty of the gathering part 312. At the same time, when welding the gathering part 312 and the conductive part, the weld can extend along the length or width direction of the first region 3121, and the two sides of the width or the two sides of the length of the weld can fall within the appropriate first region 3121, which is conducive to increasing the proportion of the outer periphery of the connecting part 313 within the first region 3121, making most of the outer periphery of the connecting part 313 less prone to cracking. Moreover, the part of the tab 311 located in the second region 3122 between the two first regions 3121 and the part of the third region 3123 located between the two second regions 3122 are easily deformable, meeting the welding shrinkage requirements and improving the problem of cracks appearing at the edge of the weld due to stress tension.

[0143] It is understood that in the above scheme, when the connecting part 313 is square, the length direction of the first region 3121 is consistent with or intersects with the length direction of the connecting part 313.

[0144] For example, the above-described layout of the first region 3121, the second region 3122, and the third region 3123, if formed by a single ultrasonic welding operation, includes a first welding structure 5 and a second welding structure 6 in the ultrasonic welding apparatus 400. The first welding structure 5 is configured as a welding head and includes a first body 51 and a first welding tooth 52. The second welding structure 6 is configured as a welding seat and includes a second body 61 and a second welding tooth 62. Both the first welding tooth 52 and the second welding tooth 62 are formed into elongated strips. Multiple first welding teeth 52 are arranged in parallel and spaced apart, and multiple second welding teeth 62 are arranged in parallel and spaced apart. When the ultrasonic welding apparatus 400 welds the electrode tab 31, the electrode tab 31 is located between the first welding structure 5 and the second welding structure 6, and the length of the first welding tooth 52 is... The direction is consistent with the length direction of the second welding tooth 62. Multiple first welding teeth 52 and multiple second welding teeth 62 are staggered in the width direction of the first welding tooth 52, so that a part of the first welding tooth 52 is directly opposite to a part of the second welding tooth 62, another part of the first welding tooth 52 is directly opposite to the interval between adjacent second welding teeth 62, and another part of the second welding tooth 62 is directly opposite to the interval between adjacent first welding teeth 52. Then, the first welding tooth 52 and the second welding tooth 62 cooperate to process the first region 3121, the first welding tooth 52 and the second body 61 cooperate to process the second region 3122, the second welding tooth 62 and the first body 51 cooperate to process the second region 3122, and the first body 51 and the second body 61 cooperate to process the third region 3123.

[0145] Of course, the above-mentioned layout of the first region 3121, the second region 3122, and the third region 3123 can also be formed by two ultrasonic welding processes. The ultrasonic welding device 400 includes a first welding structure 5 and a second welding structure 6. The first welding structure 5 is configured as a welding head and includes a first body 51 and a first welding tooth 52. The second welding structure 6 is configured as a welding head and includes a second body 61 and a second welding tooth 62. The first welding tooth 52 and the second welding tooth 62 are both formed into elongated strips. Multiple first welding teeth 52 are arranged in parallel and spaced apart, and multiple second welding teeth 62 are arranged in parallel and spaced apart. When the ultrasonic welding device 400 welds the electrode tab 31, the first welding structure 5 first welds the electrode tab 31, and the first welding tooth 52 forms a first weld mark area on the electrode tab 31. The first body 51 is then welded to the electrode tab 31. A second solder mark area is formed on the tab 31, and then the second welding structure 6 continues to weld the tab 31. The length direction of the second welding tooth 62 is consistent with the length direction of the first welding tooth 52, and the second welding tooth 62 is misaligned with the corresponding first welding tooth 52 in the width direction of the first welding tooth 52, so that the second welding tooth 62 further welds the first solder mark area to form a third solder mark area, and further welds the second solder mark area to form a fourth solder mark area. The second body 61 further welds the first solder mark area to form a fifth solder mark area, and further welds the second solder mark area to form a sixth solder mark area. The third solder mark area constitutes the first area 3121, the fourth solder mark area and the fifth solder mark area respectively constitute the second area 3122, and the sixth solder mark area constitutes the third area 3123.

[0146] Please refer to Figure 6 and Figure 7 In some embodiments, there are multiple first regions 3121, and each first region 3121 is a quadrilateral. The outer periphery of the first region 3121 includes four side edges that are connected end to end. Each side edge of the first region 3121 is respectively connected to a second region 3122. A third region 3123 is provided between two adjacent second regions 3122. It can be seen that each side edge of the first region 3121 is not directly connected to the third region 3123. The third region 3123 can be located at the corner of the first region 3121. The corner of the first region 3121 can be understood as the intersection of two adjacent side edges of the first region 3121.

[0147] In the above technical solution, the layout of the first region 3121, the second region 3122 and the third region 3123 is also relatively simple, which is conducive to simplifying the structure of the welding device, simplifying the welding process, and reducing the processing difficulty of the gathering part 312; at the same time, the part of the tab 311 located in the second region 3122 between the two first regions 3121 and the part of the third region 3123 located between the two second regions 3122 are easily deformable, which meets the welding shrinkage requirements and improves the problem of cracks appearing at the edge of the weld due to stress tension.

[0148] Please refer to Figure 6 and Figure 7 In some embodiments, multiple first regions 3121 are arranged in multiple rows and columns. Two adjacent first regions 3121 share a corresponding second region 3122 and a corresponding third region 3123, so that a second region 3122 can be connected between two adjacent first regions 3121 and a second region 3122 can be connected between two adjacent third regions 3123. Two adjacent second regions 3122 are connected to a first region 3121 in a first direction and to a third region 3123 in a second direction.

[0149] For example, multiple first regions 3121 spaced apart along a first direction X constitute a row of regions. These rows of regions are spaced apart along a second direction Y. A second region 3122 connects two adjacent first regions 3121 within the same row. A second region 3122 connects two corresponding first regions 3121 within two adjacent rows. The second regions 3122 and third regions 3123 are quadrilaterals, such that each side edge of the third region 3123 connects to a second region 3122. A first region 3121 connects two adjacent second regions 3122 in the second direction, and a third region 3123 connects two adjacent second regions 3122 in the first direction. The first and second directions intersect. For example, the first direction can be the length direction of the connecting portion 313, and the second direction can be the width direction of the connecting portion 313, or the first direction can be the width direction of the connecting portion 313, and the second direction can be the length direction of the connecting portion 313. Alternatively, the first direction can be inclined relative to the length and width directions of the connecting portion 313 (e.g., ...). Figure 7 (As shown).

[0150] Therefore, by setting two adjacent first regions 3121 to share the corresponding second region 3122 and the corresponding third region 3123, it is beneficial to reduce the number of second regions 3122 and third regions 3123, and to reduce the total area of ​​the second regions 3122 and third regions 3123. This is beneficial to increase the area of ​​the first region 3121 corresponding to the connection part 313. For example, it is beneficial to make the area where the molten pool of the laser weld is located mostly the first region 3121, which is beneficial to improve the problem of porosity in the weld molten pool and to improve the flow capacity at the connection part 313.

[0151] For example, the above-described layout of the first region 3121, the second region 3122, and the third region 3123 can be formed by two ultrasonic welding processes. The ultrasonic welding device 400 includes a first welding structure 5 and a second welding structure 6. The first welding structure 5 is configured as a welding head and includes a first body 51 and a first welding tooth 52. The second welding structure 6 is configured as a welding head and includes a second body 61 and a second welding tooth 62. Both the first welding tooth 52 and the second welding tooth 62 are formed into elongated strips. Multiple first welding teeth 52 are arranged in parallel and spaced apart, and multiple second welding teeth 62 are arranged in parallel and spaced apart. When the ultrasonic welding device 400 welds the electrode tab 31, the first welding structure 5 welds the electrode tab 31 first, and the first welding tooth 52 is welded onto the electrode tab 31. A first solder mark area is formed. The first main body 51 forms a second solder mark area on the electrode lug 31. Then, the second welding structure 6 continues to weld the electrode lug 31. The length direction of the second welding tooth 62 intersects the length direction of the first welding tooth 52, so that the second welding tooth 62 further welds the first solder mark area to form a third solder mark area and further welds the second solder mark area to form a fourth solder mark area. The second main body 61 further welds the first solder mark area to form a fifth solder mark area and further welds the second solder mark area to form a sixth solder mark area. The third solder mark area constitutes the first area 3121, the fourth solder mark area and the fifth solder mark area respectively constitute the second area 3122, and the sixth solder mark area constitutes the third area 3123.

[0152] It is worth noting that the position of the pole post 2 on the housing 1 is not limited. For example, the housing 1 may include a housing body 11 and a housing cover 12. The housing body 11 defines a space open on one side, and the housing cover 12 is located on the open side of the housing body 11 to form a receiving cavity between the housing body 11 and the housing cover 12. At this time, the surface of the housing body 11 opposite to the housing cover 12 is the first housing wall, and the wall of the housing body 11 connecting the first housing wall and the housing cover 12 is the second housing wall. At this time, the pole post 2 can be located on the first housing wall, or on the second housing wall, or on the housing cover 12. 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 disposed on the housing cover 12, or the positive electrode post 2 and the negative electrode post 2 can be simultaneously disposed on the first housing wall, or one of the positive electrode post 2 and the negative electrode post 2 can be disposed on the housing cover 12 and the other on the first housing wall, and so on.

[0153] Secondly, embodiments of this application provide a battery device 100, including a battery cell 101 from any of the above embodiments.

[0154] In the above technical solution, the improved reliability of the battery cell 101 is beneficial to improving the reliability of the battery device 100.

[0155] Thirdly, embodiments of this application provide an electrical device 1000, including the aforementioned battery device 100, which is used to provide electrical energy.

[0156] In the above technical solution, since the battery device 100 has high reliability, the use of the battery device 100 can improve the power reliability of the power-consuming device 1000.

[0157] Fourthly, embodiments of this application provide an ultrasonic welding apparatus 400 for processing the tapered portion 312 of the tab portion 31 in any of the above embodiments of this application. Please refer to... Figures 9a-12 The ultrasonic welding device 400 includes a first welding structure 5 and a second welding structure 6. The first welding structure 5 is configured as a welding head, and the second welding structure 6 is configured as a welding head or a welding base.

[0158] The first welding structure 5 includes a first body 51 and a first welding tooth 52. The first welding tooth 52 protrudes from the welding surface of the first body 51. When the first welding structure 5 participates in welding the tab 31, the first welding tooth 52 contacts the tab 311 with priority relative to the first body 51. The pre-welding force is concentrated in the part of the tab 31 that contacts the first welding tooth 52, so that the compaction degree of the area where the tab 31 and the first welding tooth 52 are opposite is greater than the compaction degree of the area where the tab 31 and the first body 51 are opposite. The second welding structure 6 includes a second body 61 and a second welding tooth 62. The second welding tooth 62 protrudes from the welding surface of the second body 61. When the second welding structure 6 participates in welding the tab 31, the second welding tooth 62 preferentially contacts the tab 311 relative to the second body 61. The pre-welding force is biased and concentrated on the part of the tab 31 that contacts the second welding tooth 62, so that the compaction degree of the area where the tab 31 and the second welding tooth 62 are opposite is greater than the compaction degree of the area where the tab 31 and the second body 61 are opposite.

[0159] Specifically, the first welding tooth 52 and the second welding tooth 62 cooperate to process the first region 3121, the first welding tooth 52 and the second body cooperate to process the second region 3122, the second welding tooth 62 and the first body 51 cooperate to process the second region 3122, and the first body 51 and the second body 61 cooperate to process the third region 3123.

[0160] For example, when the second welding structure 6 is configured as a welding base, the first welding structure 5 and the second welding structure 6 are respectively located on both sides of the thickness of the electrode lug 31. The electrode lug 31 is sandwiched between the first welding structure 5 and the second welding structure 6. The first welding tooth 52 may include a first part and a second part, and the second welding tooth 62 may include a third part and a fourth part. The first part and the third part are directly opposite each other, the second part is directly opposite the interval between adjacent second welding teeth 62, and the fourth part is directly opposite the interval between adjacent first welding teeth 52. The portion of the electrode lug 31 located between the first welding teeth 52 and the second welding teeth 62, and the portion of the first welding teeth 52 and the second welding teeth 62 directly opposite each other, are welded to the aforementioned portion of the electrode lug 31, so that the aforementioned portion of the electrode lug 31 forms a first region 312 with a higher degree of compaction. 1; The portion of the tab 31 located between the first welding tooth 52 and the second body 61, with the portions of the first welding tooth 52 and the second body 61 facing each other, is welded to the aforementioned portion of the tab 31 to form a second region 3122; The portion of the tab 31 located between the second welding tooth 62 and the first body 51, with the portions of the second welding tooth 62 and the first body 51 facing each other, is welded to the aforementioned portion of the tab 31 to form a second region 3122; The portion of the tab 31 located between the first body 51 and the second body 61, with the portions of the first body 51 and the second body 61 facing each other, is welded to the aforementioned portion of the tab 31 to form a third region 3123 with a lower degree of compaction.

[0161] For example, when the second welding structure 6 is configured as a welding head, the first welding structure 5 and the second welding structure 6 can weld the tab 31 sequentially. For instance, if the first welding structure 5 welds the tab 31 first, and the second welding structure 6 then welds the tab 31, after the first welding structure 5 welds the tab 31, the first welding tooth 52 can form a first weld mark area on the tab 31, and the first body 51 can form a second weld mark area on the tab 31. The compaction degree of the first weld mark area is greater than that of the second weld mark area. Then, the second welding structure 6 continues to weld the tab 31, and the second welding tooth... 62 further welds the first weld area to form the third weld area, and further welds the second weld area to form the fourth weld area. The second body 61 further welds the first weld area to form the fifth weld area, and further welds the second weld area to form the sixth weld area. Obviously, the compaction degree of the third weld area is greater than that of the fourth and fifth weld areas, which is greater than that of the sixth weld area. That is, the third weld area constitutes the first area 3121, the fourth and fifth weld areas constitute the second area 3122, and the sixth weld area constitutes the third area 3123.

[0162] In the above technical solution, the ultrasonic welding device 400 ultrasonically pre-welds the gathering part 312. By utilizing the protruding arrangement of the first welding tooth 52 and the second welding tooth 62, the first welding tooth 52 contacts the electrode tab 311 first when the first welding structure 5 is welded, and the second welding tooth 62 contacts the electrode tab 311 first when the second welding structure 6 is welded. This can increase the local pressure applied to the electrode tab 311 by the first welding tooth 52 and the second welding tooth 62. 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 3121. Thus, the first welding tooth 52 and the second welding tooth 62 cooperate to form the first region 3121 with a relatively large degree of compaction. The first welding tooth 52 and the second body 61 cooperate, and the second welding tooth 62 and the first body 51 cooperate to process the second region 3122 with a medium degree of compaction. The first body 51 and the second body 61 cooperate to process the third region 3123 with a relatively small degree of compaction. The ultrasonic welding device 400 has a simple structure and is easy to process the gathering part 312.

[0163] Optionally, the shape, size, and arrangement of the first welding tooth 52 can be the same as those of the second welding tooth 62. Of course, at least one aspect of their shape, size, and arrangement can be different. For example, when the second welding structure 6 is configured as a welding seat, the protrusion height of the second welding tooth 62 is less than that of the first welding tooth 52.

[0164] Please refer to Figure 12 In some embodiments, on the longitudinal section of the first welding tooth 52, the two sides of the width of the first welding tooth 52 are close to each other in a direction away from the first body 51, and the longitudinal section of the first welding tooth 52 is perpendicular to the welding surface of the first body 51; on the longitudinal section of the second welding tooth 62, the two sides of the width of the second welding tooth 62 are close to each other in a direction away from the second body 61, and the longitudinal section of the second welding tooth 62 is perpendicular to the welding surface of the second body 61. It can be seen that on the longitudinal section of the first welding tooth 52, the width of the first welding tooth 52 decreases in a direction away from the first body 51, and on the longitudinal section of the second welding tooth 62, the width of the second welding tooth 62 decreases in a direction away from the second body 61.

[0165] Therefore, when the first welding structure 5 welds the tab 31, the end of the first welding tooth 52 furthest from the first body 51 preferentially contacts the tab 31. This helps to reduce the area of ​​preferential contact of the first welding tooth 52, which helps to increase the local pressure on the tab 31 and improve the compaction degree of the welding of the tab 31. At the same time, the width of the end of the first welding tooth 52 furthest from the first body 51 is less likely to form sharp corners, making it less likely for the first welding tooth 52 to form sharp contact with the tab 311, thus improving the situation where the tab 311 is easily cracked by the first welding tooth 52. It can be seen that the above-mentioned arrangement of the first welding tooth 52 can play a certain protective role for the tab 311 while improving the compaction degree of the tab 31, thereby improving the welding yield.

[0166] Similarly, when the second welding structure 6 is welded to the tab 31, the end of the second welding tooth 62 furthest from the second body 61 preferentially contacts the tab 31. This helps to reduce the area of ​​preferential contact of the second welding tooth 62, which helps to increase the local pressure on the tab 31 and improve the compaction of the welding of the tab 31. At the same time, the width of the end of the second welding tooth 62 furthest from the second body 61 is less likely to form sharp corners, making it less likely for the second welding tooth 62 to form sharp contact with the tab 311, thus improving the situation where the tab 311 is easily cracked by the second welding tooth 62. It can be seen that the above-mentioned arrangement of the second welding tooth 62 can play a certain protective role for the tab 311 while improving the compaction of the tab 31, thereby improving the welding yield.

[0167] Please refer to Figure 12 In some embodiments, the longitudinal cross-sectional shape of the first welding tooth 52 and the longitudinal cross-sectional shape of the second welding tooth 62 are both trapezoidal. Therefore, the shapes of the first welding tooth 52 and the second welding tooth 62 are simple and easy to process. Simultaneously, the first welding tooth 52 provides a relatively large and relatively flat pressing surface, and the second welding tooth 62 provides a relatively large and relatively flat pressing surface. This facilitates the cooperation of a portion of the first welding tooth 52 with a portion of the second welding tooth 62 to process the first region 3121, and the cooperation of another portion of the first welding tooth 52 with the second body 61 to process the second region 3122, and the cooperation of another portion of the second welding tooth 62 with the first body 51 to process the second region 3122.

[0168] Please refer to Figures 9a-12 In some embodiments, both the first welding tooth 52 and the second welding tooth 62 are formed into elongated strips. There are multiple first welding teeth 52, which are arranged in parallel and spaced apart. Similarly, there are multiple second welding teeth 62, which are also arranged in parallel and spaced apart. Thus, the structure of the first welding tooth 52 is similar to that of the second welding tooth 62, and the arrangement of the first welding teeth 52 is the same as that of the second welding tooth 62. This simplifies the first welding structure 5 and the second welding structure 6, and also helps to reduce design costs.

[0169] For example, the length direction of the first welding tooth 52 may be consistent with or intersect (e.g., perpendicular) the length direction of the welding surface of the first body 51; of course, the length direction of the second welding tooth 62 may be consistent with or intersect (e.g., perpendicular) the length direction of the welding surface of the second body 61.

[0170] Please refer to Figure 11 and Figure 12 In some embodiments, the second welding structure 6 is configured as a welding base, and the length direction of the first welding tooth 52 is consistent with the length direction of the second welding tooth 62. Figure 11 and Figure 12The length direction of the first welding tooth 51 and the length direction of the second welding tooth 62 are both perpendicular to the paper surface. Therefore, it is convenient to form the first region 3121, the second region 3122 and the third region 3123 by welding in one step, simplifying the processing steps of the gathering part 312 and improving the production efficiency of the battery cell 101.

[0171] In some embodiments, the second welding structure 6 is configured as a welding head, and the length direction of the first welding tooth 52 intersects or coincides with the length direction of the second welding tooth 62. Thus, the first region 3121, the second region 3122, and the third region 3123 can be formed by two welding operations, which is relatively simple. Figure 9a In the middle, the length direction of the first welding tooth 51 is perpendicular to the plane of the paper, that is... Figure 9b The vertical direction in the middle; Figure 10a In the middle, the length direction of the second welding tooth 62 is perpendicular to the plane of the paper, that is... Figure 10b The up and down directions in the middle.

[0172] Optionally, when both the first welding structure 5 and the second welding structure 6 are constructed as welding heads, the first welding structure 5 and the second welding structure 6 can be integrated, for example, they can be integrated into one welding head. Examples include: Example 1, the first body 51 and the second body 61 are integrated into one body, with the first welding tooth 52 and the second welding tooth 62 being different welding teeth, both protruding from the integrated body; Example 2, the first body 51 and the second body 61 are integrated into one body, with the first welding tooth 52 and the corresponding second welding tooth 62 being the same welding tooth. Of course, when both the first welding structure 5 and the second welding structure 6 are constructed as welding heads, they can also be set separately.

[0173] It is understood that in Example 2 above, the welding head, which is formed by the integration of the first welding structure 5 and the second welding structure 6, first welds the electrode lug 31, and then rotates the welding head around an axis perpendicular to the welding surface at a certain angle (which can be an acute angle, a right angle, or an obtuse angle) to weld the electrode lug 31 again. The weld marks of the welding head in the two welding operations overlap at least partially to form the first region 3121, the second region 3122, and the third region 3123. Of course, in Example 2 above, the welding head, which is formed by the integration of the first welding structure 5 and the second welding structure 6, first welds the electrode lug 31 in the first position, and then moves the welding head a certain distance along the arrangement direction of multiple welding teeth (or the width direction of the welding teeth) so that the welding teeth are in the second position before welding the electrode lug 31. The weld marks of the welding head in the two welding operations overlap at least partially to form the first region 3121, the second region 3122, and the third region 3123. The welding teeth in the second position are offset from the welding teeth in the first position by a certain distance, and this offset distance can be less than the width of the welding teeth.

[0174] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. In other words, unless otherwise specified, all implementation methods and optional implementation methods of this application can be combined with each other to form new technical solutions; unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form new technical solutions.

[0175] 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; A pole post, wherein the pole post is disposed in the housing; An electrode assembly is housed in a housing and includes an electrode tab. The electrode tab includes a plurality of tab pieces, which are stacked and connected to form a convergent portion. The convergent portion has at least one first region, at least one second region, and at least one third region. The first region is connected to the third region via the second region. The plurality of tab pieces are more compacted in the first region than in the second region, and the plurality of tab pieces are more compacted in the second region than in the third region. The thickness of the plurality of tab pieces in the first region and the thickness in the second region are both less than the stacking thickness of the plurality of tab pieces in the electrode tab. A connecting portion is formed at the location of the convergent portion for electrical connection with the electrode post. A portion of the outer periphery of the connecting portion on the convergent portion is located in the first region, and a portion of the outer periphery of the connecting portion on the convergent portion is located in the second region.

2. The battery cell according to claim 1, characterized in that, A portion of the outer periphery of the connecting part on the gathering part is located in the third region.

3. The battery cell according to claim 1, characterized in that, The second region and the third region are respectively linear and they cooperate to pass through the opposite two sides of the connecting part.

4. The battery cell according to claim 1, characterized in that, The total area of ​​the first region is greater than the total area of ​​the second region, and is also greater than the total area of ​​the third region.

5. The battery cell according to claim 4, characterized in that, The total area of ​​the first region is S1, and the sum of the total areas of the second region and the third region is S2, where S1:S2≤50.

6. The battery cell according to claim 5, characterized in that, 10≤S1:S2≤25.

7. The battery cell according to claim 1, characterized in that, There are multiple first regions, and the area of ​​a single first region accounts for more than or equal to 1 / 100 of the total area of ​​the first regions.

8. The battery cell according to claim 7, characterized in that, The area of ​​a single first region accounts for 1 / 5 to 1 / 20 of the total area of ​​the first region; and / or, The number of the first region is greater than or equal to 5.

9. The battery cell according to claim 1, characterized in that, The first region is the region with the highest degree of compaction on the gathered part, and the third region is the region with the lowest degree of compaction on the gathered part.

10. The battery cell according to claim 9, characterized in that, The second region consists of multiple areas. Multiple second zones have the same degree of compaction; or, At least two of the multiple second regions have different degrees of compaction.

11. The battery cell according to claim 1, characterized in that, The converging portion is directly welded to the pole post; or... The battery cell also includes an adapter plate, and the folding part is indirectly connected to the terminal post through the adapter plate, and the folding part is directly welded to the adapter plate.

12. The battery cell according to any one of claims 1-11, characterized in that, The first region is a plurality of regions and each region is formed into a long strip. The plurality of first regions are arranged in parallel and spaced apart. Two second regions are provided between two adjacent first regions. A third region is provided between two second regions between two adjacent first regions.

13. The battery cell according to any one of claims 1-11, characterized in that, The first region is multiple, and each first region is a quadrilateral. The outer periphery of the first region includes multiple side edges that are connected end to end. Each side edge of the first region is respectively connected to the second region. A third region is provided between two adjacent second regions.

14. The battery cell according to claim 13, characterized in that, Multiple first regions are arranged in multiple rows and columns, and two adjacent first regions share a corresponding second region and a corresponding third region.

15. A battery device, characterized in that, Includes the battery cell according to any one of claims 1-14.

16. An electrical appliance, characterized in that, Includes the battery device according to claim 15.

17. An ultrasonic welding apparatus, characterized in that, For processing the gathering portion according to any one of claims 1-14, the ultrasonic welding apparatus includes a first welding structure and a second welding structure, the first welding structure being configured as a welding head, and the second welding structure being configured as a welding head or a welding base. The first welding structure includes a first body and a first welding tooth, the first welding tooth being protruding from the welding surface of the first body. The second welding structure includes a second body and a second welding tooth, the second welding tooth being protruding from the welding surface of the second body. The first welding tooth and the second welding tooth cooperate to process the first region, the first welding tooth and the second body cooperate to process the second region, the second welding tooth and the first body cooperate to process the second region, and the first body and the second body cooperate to process the third region.

18. The ultrasonic welding apparatus according to claim 17, characterized in that, On the longitudinal section of the first weld tooth, the two sides of the width of the first weld tooth approach each other in a direction away from the first body, and the longitudinal section of the first weld tooth is perpendicular to the welding surface of the first body. On the longitudinal section of the second weld tooth, the two sides of the width of the second weld tooth approach each other in a direction away from the second body, and the longitudinal section of the second weld tooth is perpendicular to the welding surface of the second body.

19. The ultrasonic welding apparatus according to claim 18, characterized in that, The longitudinal cross-sectional shape of the first welding tooth and the longitudinal cross-sectional shape of the second welding tooth are both trapezoidal.

20. The ultrasonic welding apparatus according to any one of claims 17-19, characterized in that, Both the first welding tooth and the second welding tooth are formed into an elongated shape. There are multiple first welding teeth, which are arranged in parallel and spaced apart. There are also multiple second welding teeth, which are arranged in parallel and spaced apart.

21. The ultrasonic welding apparatus according to claim 20, characterized in that, The second welding structure is configured as a welding base, wherein the length direction of the first welding tooth is consistent with the length direction of the second welding tooth; or... The second welding structure is configured as a welding head, wherein the length direction of the first welding tooth intersects with or coincides with the length direction of the second welding tooth.

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