Battery cell, battery, electric device, and energy storage device

Abstract

The application provides a battery monomer, a battery, a power utilization device and an energy storage device, and belongs to the technical field of batteries. The battery monomer comprises an electrode assembly, a shell assembly and a current collecting member. The electrode assembly comprises a pole piece, and the pole piece comprises a first pole lug which is arranged protruding along a first direction. The shell assembly is used for accommodating the electrode assembly and comprises a first electrode lead-out part. The current collecting member comprises a first connecting piece used for connecting with the first electrode lead-out part and a second connecting piece used for connecting with the first pole lug. The base metal of the first connecting piece is different from that of the second connecting piece. At least one of the first connecting piece and the second connecting piece is provided with a first groove, the first connecting piece and the second connecting piece are welded and form a first welding mark, and the first welding mark is provided with at least one gap part. In a projection plane perpendicular to the first direction, the orthographic projection of the first groove is at least partially located in the orthographic projection of the gap part, so that the welding stress is released through the first groove when the first connecting piece and the second connecting piece are welded, and the welding quality is improved.

Description

Technical Field

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

[0002] Energy conservation and emission reduction are key to the sustainable development of the automotive industry, and electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of this sustainable development. For electric vehicles, battery technology is a crucial factor in their development.

[0003] In a single battery cell, to improve the charge / discharge rate, a current collector is used to connect the tabs to the corresponding electrode leads. However, the tabs, current collectors, and electrode leads may be made of different materials. When welding dissimilar metals, welding deformation may occur due to the differences in material properties, affecting the welding quality between the current collector and the tabs / electrode leads. Utility Model Content

[0004] This application aims to at least address one of the technical problems existing in the background art. Therefore, one object of this application is to provide a battery cell, battery, power supply device, and energy storage device to improve the welding quality between internal components of the battery cell.

[0005] An embodiment of the first aspect of this application provides a battery cell, including an electrode assembly, a housing assembly, and a current collector. The electrode assembly includes an electrode sheet, each electrode sheet having a first tab protruding along a first direction. The housing assembly is used to house the electrode assembly and includes a first electrode lead-out portion. The current collector includes a first connector and a second connector. The first connector is used to connect to the first electrode lead-out portion, and the second connector is used to connect to the first tab. The base metals of the first connector and the second connector are different. At least one of the first connector and the second connector has a first groove, and the first connector and the second connector are welded to form a first solder mark, the first solder mark having at least one notch. In a projection plane perpendicular to the first direction, the orthographic projection of the first groove is at least partially located within the orthographic projection of the notch.

[0006] In the technical solution of this application embodiment, the current collector includes a first connector and a second connector. The first connector is used to connect to the first electrode lead-out portion. The first connector and the second connector are welded to form a first weld mark. The second connector is used to connect to the first electrode tab. At least one of the first connector and the second connector is provided with a first groove. The first weld mark is provided with at least one notch. In a projection plane perpendicular to the first direction, the orthographic projection of the first groove is at least partially located within the orthographic projection of the notch. This is to alleviate welding stress through the first groove when welding the first connector and the second connector, improve the incoming material quality of the current collector, and further improve the connection quality between the current collector and the first electrode tab and the first electrode lead-out portion. In addition, the base metal of the first connector is different from the base metal of the second connector, which can better meet the welding requirements caused by different welding objects, reduce the risk of welding defects in subsequent welding of the current collector, facilitate the implementation of subsequent welding processes, and improve welding quality.

[0007] In some embodiments, the first connector and the second connector are stacked along a first direction. This can improve the structural strength of the current collector, help control welding deformation, meet the welding requirements of different objects, and optimize the internal spatial arrangement of the battery cell.

[0008] In some embodiments, the first connector and the second connector are mated along a second direction, which is perpendicular to the thickness direction of the second connector. This reduces the space occupied by the current collector along the height direction of the battery cell, which is beneficial for improving the volumetric energy density.

[0009] In some embodiments, the first groove is located on the surface of the first connector. The maximum groove depth along the first direction is less than the thickness of the first connector. This allows for the relief of welding stress while simultaneously ensuring good overall structural strength of the first connector and simplifying welding positioning with the second connector.

[0010] In some embodiments, at least a portion of the first groove extends through the first connector along the first direction. This creates a free surface to further alleviate welding stress when welding the first and second connectors, thereby improving the overall quality of the current collection component.

[0011] In some embodiments, the first groove is located on the surface of the second connector. Along a first direction, the maximum groove depth of the first groove is less than the thickness of the second connector. This allows for the relief of welding stress while ensuring good structural strength of the second connector.

[0012] In some embodiments, at least a portion of the first groove extends through the second connector along the first direction. This can further alleviate welding stress when welding the first and second connectors.

[0013] In some embodiments, both the first connector and the second connector are provided with a first groove; in a projection plane perpendicular to the first direction, the orthographic projection of the first groove on the first connector is completely offset from the orthographic projection of the first groove on the second connector. This further alleviates welding stress during welding of the first connector and the second connector, and coordinates the deformation differences between the first connector and the second connector.

[0014] In some embodiments, both the first connector and the second connector are provided with a first groove; in a projection plane perpendicular to the first direction, the orthographic projection of the first groove on the first connector at least partially overlaps with the orthographic projection of the first groove on the second connector. This allows for the simultaneous relief of welding stress between the first connector and the second connector, and suppresses welding deformation of the first connector and the second connector.

[0015] In some embodiments, the first weld mark has multiple notches that break the first weld mark to form multiple sub-weld marks; wherein, in a projection plane perpendicular to the first direction, the orthographic projection of any first groove is at least partially disposed within the orthographic projection of the notch between two adjacent sub-weld marks. This further alleviates welding stress and reduces the probability of deformation of the current collector.

[0016] In some embodiments, in a projection plane perpendicular to the first direction, the sum of the central angles α formed by the geometric centers of the orthographic projection of the first solder mark relative to the orthographic projection of the second connector satisfies: 210° ≤ α < 360°, preferably 250° ≤ α ≤ 350°. This allows for the reduction of welding stress while increasing the flow area of ​​the solder mark.

[0017] In some embodiments, the second connector includes a first part and a second part. The first part is located in the central region of the second connector and is used for welding to the first tab. The second part surrounds the outer periphery of the first part and is used for welding to the first connector. This allows the welding positions of the second connector and the first tab and the first connector to be staggered, reducing the mutual interference when welding the second connector and the first tab, as well as when welding the second connector and the first connector.

[0018] In some embodiments, the first connector includes a hollow area located in the central region, and the first connector and the second connector are stacked along a first direction, with the first part facing the hollow area. This reduces the impact of the first connector on welding the second connector and the first electrode tab, facilitating the welding of the second connector to the first electrode tab.

[0019] In some embodiments, the connector includes a hollow area in the central region, the first connector and the second connector are mated along a second direction, and the second connector is located within the hollow area, the second direction being perpendicular to the thickness direction of the second connector. This reduces the overall height of the current collector, and the staggered arrangement of the first and second connectors allows for staggered solder joints, thereby reducing the impact during welding and improving the welding quality of the battery cells.

[0020] In some embodiments, the first connector is a closed ring, and a plurality of first grooves disposed on the first connector are circumferentially spaced along the geometric center of the first connector. In this way, when welding the first connector and the second connector, the stress on the first connector can be further relieved, and the deformation of the current collecting component and the probability of welding defects can be reduced.

[0021] In some embodiments, any of the first grooves disposed on the first connector extends radially along the geometric center of the first connector. In this way, the extension direction of the first groove can intersect with the extension direction of the solder stamp, thereby better releasing welding stress and improving the incoming material quality of the current collector.

[0022] In some embodiments, the extension direction of the first groove disposed on the first connector intersects the extension direction of the first connector, and at least one first groove is configured to completely disconnect the first connector. This provides a space for stress relief during welding of the first connector and the second connector, thereby further mitigating deformation and cracking of the current collector caused by the difference in deformation between the first and second connectors, and further improving the connection quality between the current collector and the first tab and the first electrode lead-out portion.

[0023] In some embodiments, the first groove provided on the second connector is located at the second part of the second connector. This can alleviate the welding stress on the second connector and reduce the amount of deformation of the second connector caused by welding when welding the first connector and the second connector.

[0024] In some embodiments, a plurality of first grooves disposed on the second connector extend radially along the geometric center of the second connector and are circumferentially spaced along the geometric center of the second connector. This further alleviates stress on the second connector during welding of the first and second connectors, reduces deformation of the current collecting member and the probability of welding defects, and reduces the impact of the first grooves on subsequent welding of the second connector.

[0025] In some embodiments, the first part of the second connector further includes a second groove. The second groove extends through the second connector along a first direction, or the groove depth along the first direction is less than the thickness of the second connector. This provides stress relief space for welding stress when welding the second connector to the first tab, reducing the probability of welding deformation in the current collector.

[0026] In some embodiments, the extension direction of at least one second groove coincides with the extension direction of the first groove disposed on the second connector, and both extend radially along the geometric center of the second connector. This reduces the mutual influence between preceding and following welding processes and alleviates welding stress deformation.

[0027] In some embodiments, the extension direction of at least one second groove is different from the extension direction of the first groove disposed on the second connector. This can alleviate the stress during welding of the first connector and the second connector, and also alleviate the stress during welding of the second connector and the first tab.

[0028] In some embodiments, the number of second grooves is multiple, and the multiple second grooves are arranged circumferentially at intervals along the geometric center of the second connector. In this way, the stress during welding of the second connector and the first electrode lug can be further relieved, the deformation of the current collector can be reduced, and the welding quality of the current collector and the first electrode lug can be improved.

[0029] In some embodiments, the number of second grooves is multiple, with at least two second grooves having different extension lengths. This facilitates welding positioning between the first and second connectors and reduces overall warping of the second connector due to welding deformation, thereby reducing deformation when the second connector and the first connector are combined, which is beneficial to improving the subsequent welding quality of the current collector component.

[0030] In some embodiments, the second connector has a central through hole, and one end of at least one second groove communicates with the central through hole. This facilitates welding positioning during the welding of the second connector and the first electrode tab, while simultaneously alleviating welding stress.

[0031] In some embodiments, both the second groove and the first groove disposed on the second connector extend radially along the geometric center of the second connector. Furthermore, along the extension direction of either the second groove or the first groove, the ratio k of the effective length of the ungrooved portion from the geometric center to the outer edge of the second connector to the total length from the geometric center to the outer edge of the second connection portion satisfies: 1 / 6 ≤ k ≤ 5 / 6. This ensures sufficient welding area when the second connector is welded to the first electrode tab, while also maintaining the structural strength of the current collector itself, reducing welding deformation, and thus improving the welding quality between the current collector and the first electrode tab.

[0032] In some embodiments, the first electrode lead-out is welded to the first connector to form a second solder mark, and the orthographic projection of the second solder mark on the current collector is offset from the first solder mark. In this way, the area where the first connector is welded to the second connector and the area where the first connector is welded to the first electrode lead-out can be distinguished, which helps to reduce the welding impact when welding the second connector to the first connector and the first connector to the first electrode lead-out, and to alleviate welding deformation.

[0033] In some embodiments, the base metal of the second connector is copper; the base metal of the first connector is steel or aluminum. This allows for better adaptation to subsequent welding processes and improves the overall quality of the battery.

[0034] In some embodiments, the first connector includes a first metal layer and a first flux layer, the first flux layer being disposed on at least one surface of the first metal layer. This can mitigate welding defects caused by differences in material welding properties and improve the welding quality inside the current collector or the welding quality between the current collector and external components.

[0035] In some embodiments, the second connector includes a second metal layer and a second flux layer, the second flux layer being disposed on at least one surface of the second metal layer. This can mitigate welding defects caused by differences in material welding properties and improve the welding quality inside the current collector or the welding quality between it and external components.

[0036] In some embodiments, the electrode assembly further includes a second tab with a polarity different from the first tab, the first tab and the second tab being located at opposite ends of the electrode assembly along a first direction. The housing assembly includes a housing and an end cap, the housing forming a receiving space for accommodating the electrode assembly, the housing including an end wall at one end of the receiving space and an opening at the other end of the receiving space; the end cap is connected to the housing to close the opening; the first electrode lead-out is either the end cap or the housing. The housing assembly further includes a second electrode lead-out, the second electrode lead-out being insulated through the end wall and electrically connected to the second tab. This allows current from the second tab to be conducted to the outside of the housing assembly through the second electrode lead-out.

[0037] An embodiment of the second aspect of this application provides a battery comprising the battery cell described in the above embodiments.

[0038] An embodiment of the third aspect of this application provides an electrical device that includes the battery described in the above embodiments, the battery being used to provide electrical energy.

[0039] An embodiment of the fourth aspect of this application provides an energy storage device comprising the battery described in the above embodiments, the battery being used to store electrical energy and provide electrical energy.

[0040] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0041] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0042] Figure 1 This is a schematic diagram of the vehicle structure according to some embodiments of this application;

[0043] Figure 2 This is an exploded structural diagram of a battery according to some embodiments of this application;

[0044] Figure 3 This is an exploded structural diagram of a battery cell according to some embodiments of this application;

[0045] Figure 4 This is a cross-sectional view of a battery cell according to some embodiments of this application;

[0046] Figure 5 This is a schematic diagram of the structure of a current collection component according to some embodiments of this application;

[0047] Figure 6 This is a schematic diagram of the structure of another current collection component according to some embodiments of this application;

[0048] Figure 7 This is a schematic diagram of the structure of a first connector according to some embodiments of this application;

[0049] Figure 8 This is a schematic diagram of the structure of another first connector according to some embodiments of this application;

[0050] Figure 9 This is a schematic diagram of the structure of a second connector according to some embodiments of this application;

[0051] Figure 10 This is a schematic diagram of the structure of another second connector according to some embodiments of this application;

[0052] Figure 11 This is an exploded structural diagram of the current collection component in some embodiments of this application.

[0053] Figure 12 This is a top view of a current collection component according to some embodiments of this application;

[0054] Figure 13 This is a schematic diagram of the structure of another first connector according to some embodiments of this application;

[0055] Figure 14 This is a schematic diagram of the structure of yet another second connector according to some embodiments of this application;

[0056] Figure 15 This is a schematic diagram of the structure of the first connector and the second connector in some embodiments of this application.

[0057] Explanation of reference numerals in the attached figures:

[0058] 1000 vehicles;

[0059] Battery 100, controller 200, motor 300;

[0060] Box 10, Part 11, Part 2 12;

[0061] Battery cell 20, electrode assembly 21, first electrode tab 211, second electrode tab 212;

[0062] The outer casing assembly 22 includes a first electrode lead-out portion 22A, a second electrode lead-out portion 22B, a housing 221, a side wall 2211, an end wall 2212, and an end cap 222.

[0063] The current collection component 23 includes a first connector 231, a first surface 231A, a second surface 231B, a hollow area 231C, a first metal layer 2311, and a first flux layer 2312; a second connector 232, a third surface 232A, a fourth surface 232B, a central through hole 232C, a first part 2321, a second part 2322, a second metal layer 2323, and a second flux layer 2324; a first solder mark 241, a notch 241A, a sub-solder mark 2411, and a second solder mark 242; a first groove 251, a second groove 252, a first slot 2521, and a second slot 2522. Detailed Implementation

[0064] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0065] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein 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 specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0066] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0067] In this document, the term "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 throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0068] In the description of the embodiments 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, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0069] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0070] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0071] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0072] Currently, judging from market trends, the application of power batteries is becoming increasingly widespread. Power batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. With the continuous expansion of power battery applications, market demand is also constantly increasing.

[0073] In a single battery cell, a current-collecting component is fixedly connected to the electrode leads and tabs to form a current path. The current-collecting component is connected to the tabs and the electrode leads by welding to achieve a fixed connection. However, because the current-collecting component and the electrode leads are often made of different materials, inconsistent deformation can occur during welding due to the different material properties.

[0074] Based on the above considerations, in order to improve the connection quality between the current collector and the tabs and electrode leads, this application provides a battery cell. An embodiment of the first aspect of this application provides a battery cell including an electrode assembly, a housing assembly, and a current collector. The electrode assembly includes an electrode sheet, and the electrode sheet includes a first tab protruding along a first direction. The housing assembly is used to house the electrode assembly and includes a first electrode lead. The current collector includes a first connector and a second connector. The first connector is used to connect to the first electrode lead, and the second connector is used to connect to the first tab. The base metals of the first connector and the second connector are different. At least one of the first and second connectors has a first groove. The first connector and the second connector are welded to form a first weld mark, and the first weld mark has at least one notch. In a projection plane perpendicular to the first direction, the orthographic projection of the first groove is at least partially located within the orthographic projection of the notch. Thus, when welding the first and second connectors, the first groove can alleviate welding stress, improve the incoming material quality of the current collector, and further enhance the connection quality between the current collector and the first tab and the first electrode lead.

[0075] The battery cells disclosed in this application can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft. A power system for such an electrical device can be constructed using battery cells and batteries disclosed in this application, which helps to improve the stability of the power system.

[0076] 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.

[0077] For ease of explanation, the following embodiments will be described using a vehicle 1000 as an example of an electrical device according to an embodiment of this application.

[0078] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle provided in some embodiments of this application. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle, or a range-extended electric vehicle, etc. A battery 100 is disposed inside the vehicle 1000, and the battery 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery 100 can be used to power the vehicle 1000; for example, the battery 100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during startup, navigation, and driving.

[0079] In some embodiments of this application, the battery 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0080] Please refer to Figure 2 , Figure 2This is an exploded structural diagram of a battery provided in some embodiments of this application. The battery 100 includes a housing 10 and a battery cell 20, with the battery cell 20 housed within the housing 10. The housing 10 provides a space for the battery cell 20 and can have various structures. In some embodiments, the housing 10 may include a first portion 11 and a second portion 12, which overlap each other, jointly defining a space for accommodating the battery cell 20. The second portion 12 may be a hollow structure with one open end, and the first portion 11 may be a plate-like structure, covering the open side of the second portion 12 so that the first portion 11 and the second portion 12 jointly define the space. Alternatively, the first portion 11 and the second portion 12 may both be hollow structures with one open side, with the open side of the first portion 11 covering the open side of the second portion 12. Of course, the housing 10 formed by the first portion 11 and the second portion 12 can have various shapes, such as a cylinder, a cuboid, etc.

[0081] In battery 100, there can be multiple battery cells 20, which can be connected in series, parallel, or in a mixed manner. A mixed connection means that multiple battery cells 20 are connected in both series and parallel configurations. Multiple battery cells 20 can be directly connected in series, parallel, or in a mixed manner, and then the entire assembly of the multiple battery cells 20 is housed within the housing 10. Alternatively, battery 100 can also be composed of multiple battery cells 20 first connected in series, parallel, or in a mixed manner to form a battery module, and then multiple battery modules are connected in series, parallel, or in a mixed manner to form a whole, which is also housed within the housing 10. Battery 100 may also include other structures; for example, it may include a busbar component for electrical connection between the multiple battery cells 20.

[0082] Each battery cell 20 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited to these. The battery cell 20 can be cylindrical, flat, cuboid, or other shapes.

[0083] Please continue reading. Figures 3 to 12 , Figure 3 This is an exploded structural diagram of a battery cell according to some embodiments of this application. Figure 4 This is a cross-sectional view of a battery cell according to some embodiments of this application. Figure 5 This is a schematic diagram of the structure of a current collection component according to some embodiments of this application; Figure 6 This is a schematic diagram of the structure of another current collection component according to some embodiments of this application; Figure 7 This is a schematic diagram of the structure of a first connector according to some embodiments of this application; Figure 8 This is a schematic diagram of the structure of another first connector according to some embodiments of this application; Figure 9This is a schematic diagram of the structure of a second connector according to some embodiments of this application; Figure 10 This is a schematic diagram of the structure of another second connector according to some embodiments of this application; Figure 11 This is an exploded structural diagram of the current collection component in some embodiments of this application. Figure 12 This is a top view of a current collection component according to some embodiments of this application.

[0084] A battery cell 20 refers to the smallest unit that makes up a battery. A battery cell 20 includes an electrode assembly 21, a housing assembly 22, and a current collector 23.

[0085] The electrode assembly 21 includes an electrode sheet, and the electrode sheet includes a first tab 211 protruding along a first direction.

[0086] The housing assembly 22 is used to house the electrode assembly 21, and the housing assembly 22 includes a first electrode lead-out portion 22A.

[0087] The current collector 23 includes a first connector 231 and a second connector 232. The first connector 231 is used to connect to the first electrode lead-out portion 22A. The second connector 232 is used to connect to the first electrode tab 211. The base metals of the first connector 231 and the second connector 232 are different.

[0088] In this embodiment, at least one of the first connector 231 and the second connector 232 is provided with a first groove 251. The first connector 231 and the second connector 232 are welded to form a first weld mark 241, and the first weld mark 241 is provided with at least one notch 241A. In a projection plane perpendicular to the first direction X, the orthographic projection of the first groove 251 is at least partially located within the orthographic projection of the notch 241.

[0089] Electrode assembly 21 is the component in the battery cell 20 where electrochemical reactions occur. Electrode assembly 21 includes electrode sheets, which can be either positive or negative electrodes. Electrode assembly 21 can be formed by winding or stacking positive and negative electrode sheets, and typically a separator is provided between the positive and negative electrode sheets. Each electrode sheet includes a main body and tabs; specifically, the portions of the electrode sheet containing active material each constitute the main body, and the portions without active material each constitute the tabs. The positive and negative tabs can be located together at one end of the main body or separately at both ends of the main body. During the charging and discharging process of the battery, the positive and negative active materials react with the electrolyte, and the tabs connect to the corresponding electrode leads to form a current loop.

[0090] In one example, the electrode can be a positive electrode, and the first tab 211 can be a positive tab, then the first electrode lead-out portion 22A is the positive electrode lead-out portion. In another example, the electrode can be a negative electrode, and the first tab 211 can also be a negative tab, then the first electrode lead-out portion 22A is the negative electrode lead-out portion.

[0091] A first tab 211 protrudes along a first direction X and is disposed on the main body of the electrode sheet. In some embodiments, the first tab 211 may be a full tab with a current collector extending along the first direction X and protruding relative to the main body. In other embodiments, the first tab 211 may be a die-cut tab with a current collector extending along the first direction X and protruding relative to the main body. The first direction X is the direction in which the tab of the electrode assembly 21 exits; for example, for a wound electrode assembly, the first direction X is parallel to the winding axis of the electrode assembly 21.

[0092] The housing assembly 22 is a component used to form the internal environment of the battery cell 20. This internal environment can accommodate the electrode assembly 21, electrolyte, and other components. The housing assembly 22 may contain one or more electrode assemblies 21. The housing assembly 22 can be of various shapes and sizes, such as cuboid, cylindrical, or hexagonal prism. The shape of the housing assembly 22 can be determined based on the specific shape and size of the electrode assembly 21. The housing assembly 22 can be made of various materials, such as iron, aluminum, stainless steel, or aluminum alloy.

[0093] The housing assembly 22 includes a housing 221 and an end cap 222. The first electrode lead-out portion 22A may be a conductive component, such as a terminal post, that passes through the housing 221 or the end cap 222. In some embodiments, the first electrode lead-out portion 22A may also be the housing 221 or the end cap 222, that is, the first electrode tab 211 is electrically connected to the housing 221 or the end cap 222 through the current collector 23, so that the housing 221 or the end cap 222 serves as the first electrode lead-out portion 22A of the first electrode tab 211. The first electrode lead-out portion 22A may be a metal layer made of a single material, or a metal layer made of multiple different materials, or it may be composed of multiple materials with different functions stacked together.

[0094] The housing 221 is a component used to cooperate with the end cap 222 to form the internal environment of the battery cell 20. This internal environment can accommodate the cell assembly 23, electrolyte, and other components. The housing 221 and the end cap 222 can be independent components. An opening can be provided on the housing 221, and the end cap 222 closes the opening to form the internal environment of the battery cell 20. Alternatively, the end cap 222 and the housing 221 can be integrated. Specifically, the end cap 222 and the housing 221 can form a common connecting surface before other components are inserted into the housing. When it is necessary to encapsulate the interior of the housing 221, the end cap 222 closes the housing 221. The housing 221 can have various shapes and sizes, such as cuboid, cylindrical, or hexagonal prism. Specifically, the shape of the housing 221 can be determined according to the specific shape and size of the electrode assembly 2123. The shell 221 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. This application embodiment does not impose any special restrictions on this.

[0095] The housing 221 may include a sidewall 2211 and an endwall 2212 located at one end of the sidewall 2211, such as Figure 4 As shown, the sidewall 2211 and the endwall 2212 can be integrally stamped or formed by welding. The sidewall 2211 and the endwall 2212 together form a receiving space for accommodating the electrode assembly 21. One end of the receiving space is the endwall 2212, and the other end opposite to the endwall 2212 is an opening.

[0096] By separately providing the housing 221 and the end cap 222, the requirements for accommodating the electrode assembly 21 can be better met. The housing 221 or the end cap 222, as the first electrode lead-out part 22A, can simplify the structure of the battery.

[0097] End cap 222 refers to a component that covers the opening of housing 221 to isolate the internal environment of battery cell 20 from the external environment. The shape of end cap 222 can be adapted to the shape of housing 221 to fit it. Optionally, end cap 222 can be made of a material with certain hardness and strength (such as aluminum alloy), so that end cap 222 is less prone to deformation under pressure and impact, enabling battery cell 20 to have higher structural strength and improved safety performance. The material of end cap 222 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose any special limitations on this.

[0098] The current collector 23 is a current collector component made of conductive material. During the welding and assembly of the battery cells, the incoming materials for the current collector 23 include a first connector 231 and a second connector 232 that have already been welded together. The first connector 231 is fixedly connected to the first electrode lead-out portion 22A of the casing assembly 22 by welding, specifically laser welding, ultrasonic welding, resistance welding, etc. The second connector 232 is electrically connected to the first electrode tab 211, specifically by welding, specifically laser welding, ultrasonic welding, resistance welding, etc. The current collector 23 is connected to the first electrode tab 211 and the casing assembly 22 respectively through the first connector 231 and the second connector 232, collecting the current generated by the electrode assembly 21 and connecting it to the second electrode lead-out portion 22B to form a current loop.

[0099] The first connector 231 can be a flat structural component or an irregular shape with flanges. The first connector 231 can be welded to the end cap 222, for example by through-welding; it can also be welded to the inner wall of the housing 221, for example by through-welding or butt welding.

[0100] The second connector 232 can be flat, and its specific shape can be set as needed. This application embodiment does not limit this.

[0101] The base metal refers to the main component metal in a material (such as an alloy or composite material), for example, a metallic element with a mass fraction greater than 50%. Different base metal materials will have varying properties. The first connector 231 is used for welding to the second connector 232 and the first electrode lead-out portion 22A, while the second connector 232 is used for welding to the first connector 231 and the first electrode tab 211. Since the welding objects are different, the selection of materials and processing must consider the welding process requirements and other performance requirements when welding to these objects, thereby meeting different connection needs.

[0102] Therefore, the material of the first connector 231 and the material of the first electrode lead 22A can be set to be the same, so that the first connector 231 and the first electrode lead 22A can be fused smoothly to meet the overcurrent requirements and strength requirements; the material of the second connector 232 and the material of the first tab 211 can be set to be the same, so that the welding of the current collector 23 and the electrode assembly 21 can also meet the overcurrent requirements.

[0103] The current collecting member 23 can be disposed along the first direction X at the end of the first electrode 211 away from the main body. In some embodiments, the first direction X can be a direction parallel to the thickness direction of the second connector 232. Correspondingly, the projection plane perpendicular to the first direction X is a plane perpendicular to the thickness direction of the second connector 232. In some examples, the projection plane perpendicular to the first direction X can be the plane containing either of the two surfaces of the second connector 232 that are disposed opposite each other along its thickness direction.

[0104] The first weld mark 241 is the weld mark formed by welding the first connector 231 and the second connector 232. The first groove 251 is a groove that may or may not penetrate the first connector 231 or the second connector 232 along the first direction X.

[0105] The first solder mark 241 having at least one notch 241A means that the shape of the orthographic projection of the first solder mark 241 in a projection plane perpendicular to the first direction X is not closed, and the unclosed part corresponds to the position of the orthographic projection of the first groove 251 in a projection plane perpendicular to the first direction X. The orthographic projection of the first groove 251 being at least partially located within the orthographic projection of the notch 241A in the projection plane perpendicular to the first direction X means that the orthographic projection of the first groove 251 at least partially overlaps with the orthographic projection of the notch 241A in the projection plane perpendicular to the first direction X.

[0106] The warpage of the current collector 23 can be less than or equal to 0.3 mm, so that when selecting the current collector 23, the warpage can be used to quickly determine whether the current collector 23 meets the assembly requirements. Specifically, the lower surface of the second connector 232 of the current collector 23 away from the first connector 231 can be placed on a horizontal plane, and the warpage of the current collector 23 can be obtained by measuring the thickness difference at different positions on the upper surface of the first connector 231.

[0107] By providing a first groove 251 in at least one of the first connector 231 and the second connector 232, and providing at least one notch 241A in the first solder mark 241, and by placing the orthographic projection of the first groove 251 at least partially within the orthographic projection of the notch 241A in a projection plane perpendicular to the first direction X, the welding stress is relieved by the first groove 251 when welding the first connector 231 and the second connector 232, thereby improving the incoming material quality of the current collector 23, and further improving the connection quality between the current collector 23 and the first tab 211 and the first electrode lead-out portion 22A.

[0108] In addition, the base metal of the first connector 231 is different from the base metal of the second connector 232, which can better meet the welding requirements caused by different welding objects, reduce the risk of welding defects in subsequent welding of the current collector 23, and is more conducive to the implementation of subsequent welding processes and improve welding quality.

[0109] Please continue reading. Figure 5 and Figures 7-10 According to some embodiments of this application, the first connector 231 and the second connector 232 are stacked along the first direction X.

[0110] In some embodiments, the first connector 231 and the second connector 232 being stacked along the first direction X means that the first connector 231 and the second connector 232 are stacked along the thickness direction of the second connector 232. That is, along the first direction X, the first connector 231 is located above or below the second connector 232.

[0111] In some embodiments, the first connector 231 includes a first surface 231A and a second plane 231B disposed opposite to each other, and the second connector 232 includes a third surface 232A and a fourth plane 232B disposed opposite to each other. When the first connector 231 and the second connector 232 are stacked along the first direction X, the first surface 231A and the third surface 232A are in contact with each other. In some examples, the thickness of the first connector 231 and the second connector 232 is uniform. Without considering deformation errors caused by processing or manufacturing, the first surface 231A, the second plane 231B, the third surface 232A, and the fourth plane 232B are all flat surfaces and parallel to each other. The projection plane perpendicular to the first direction X can refer to a plane parallel to the first surface 231A or the second plane 231B of the first connector 231.

[0112] By stacking the first connector 231 and the second connector 232 along the first direction X, the first connector 231 and the second connector 232 are arranged along the first direction X. This improves the structural strength of the current collector 23, helps control welding deformation, meets the welding requirements of different objects, and optimizes the internal spatial arrangement of the battery cell.

[0113] Please continue reading. Figures 6-10 According to some embodiments of this application, the first connector 231 and the second connector 232 are mated along a second direction Y, and the second direction Y is perpendicular to the thickness direction of the second connector 232.

[0114] The first connector 231 and the second connector 232 being butt-welded along the second direction Y means that the first connector 231 and the second connector 232 are adjacent to each other in the second direction Y. In this case, the first weld mark 241 can be obtained by butt welding the butt joint of the two connectors. In some embodiments, the first connector 231 and the second connector 232 may have the same thickness or different thicknesses.

[0115] In some embodiments, the first connector 231 is annular, comprising a first surface 231A and a second plane 231B disposed opposite to each other, and a first side surface and a second side surface disposed opposite to each other, wherein the first side surface and the second side surface are respectively an outer side surface and an inner side surface connecting the first surface 231A and the second plane 231B. The second connector 232 is flat, comprising a third surface 232A and a fourth plane 232B disposed opposite to each other along the thickness direction, and a third side surface connecting the third surface 232A and the fourth plane 232B. The second side surface and the third side surface are butt-welded together along the second direction Y, and a first solder mark 241 is formed between the first connector 231 and the second connector 232 by butt welding.

[0116] In some embodiments, the second direction Y may be parallel to the third surface 232A or the fourth plane 232B of the second connector 232. In other embodiments, the second direction Y may be perpendicular to the first direction X.

[0117] By arranging the first connector 231 and the second connector 232 together along the second direction Y, the arrangement space occupied by the first connector 231 and the second connector 232 in the first direction X is reduced, which is beneficial to improving the volumetric energy density.

[0118] Please continue reading. Figure 7 According to some embodiments of this application, the first groove 251 is located on the surface of the first connector 231. Specifically, along the first direction X, the maximum groove depth of the first groove 251 is less than the thickness of the first connector 231.

[0119] Please continue reading. Figure 8 According to some embodiments of this application, at least a portion of the first groove 251 extends through the first connector 231 along the first direction X.

[0120] In some embodiments, the surface of the first connector 231 includes a first surface 231A and a second surface 231B. At least one of the first surface 231A and the second surface 231B may be provided with a first groove 251.

[0121] In some embodiments, the first surface 231A is provided with at least one first groove 251, and the groove depth of any first groove 251 is less than the thickness of the first connector 231. When multiple first grooves 251 are provided on the first surface 231A, the groove depths of the multiple first grooves 251 may be the same or different.

[0122] In some embodiments, the first connector 231 and the second connector 232 are stacked along the first direction X. When the first surface 231A and the third surface 232A are welded together, a first groove 251 is provided on the first surface 231A. The first weld mark 241 may be affected by the first groove 251 and intermittently form a notch 241A. For example, the portions of the first connector 231 and the second connector 232 corresponding to the first groove 251 are not welded together because of the presence of the first groove 251. That is, the first weld mark 241 is intermittently provided due to the first groove 251 provided on the first surface 231A, and the position where the first weld mark 241 is interrupted corresponds to the position where the notch 241A is formed and the position where the first groove 251 is located.

[0123] In some embodiments, the second surface 231B is provided with at least one first groove 251, and the groove depth of any first groove 251 is less than the thickness of the first connector 231. When multiple first grooves 251 are provided on the second surface 231B, the groove depths of the multiple first grooves 251 may be the same or different.

[0124] In some embodiments, the first connector 231 and the second connector 232 are stacked along the first direction X. When the first surface 231A and the third surface 232A are welded together, a first groove 251 is provided on the second surface 231B. In order to relieve welding stress, the first weld mark 241 can be discontinuously or non-closed to form at least one notch 241A. In the projection plane perpendicular to the first direction X, the orthographic projection of the first groove 251 is at least partially located within the orthographic projection of the notch 241A.

[0125] In some embodiments, the first connector 231 and the second connector 232 are mated along the second direction Y. To alleviate welding stress, the first weld mark 241 can be discontinuously or non-closed to form a notch 241A. In a projection plane perpendicular to the first direction X, the orthographic projection of the first groove 251 is directly opposite to the orthographic projection of the notch 241A.

[0126] The groove depth refers to the dimension of the first groove 251 extending along the first direction X. The maximum groove depth being less than the thickness of the first connector 231 means that the dimension of any first groove 251 extending along the first direction X is less than the thickness of the first connector 231, that is, the first groove 251 does not penetrate the position of its component along the thickness direction.

[0127] Please continue reading. Figure 8The statement that at least a portion of the first groove 251 penetrates the first connector 231 along the first direction X means that at least a portion of the first groove 251 has a dimension along the first direction X equal to the thickness of the first connector 231. That is, in some embodiments, a first groove 251 penetrating the first connector 231 along the first direction X and a first groove 251 not penetrating the first connector 231 can coexist.

[0128] By positioning the first groove 251 on the surface of the first connector 231 and along the first direction X, and ensuring that the maximum groove depth of the first groove 251 is less than the thickness of the first connector 231, welding stress can be relieved while maintaining the structural strength of the current collection component 23.

[0129] By allowing at least a portion of the first groove 251 to penetrate the first connector 231 along the first direction X, the welding stress during welding of the first connector 231 and the second connector 232 can be further effectively released, welding deformation can be reduced, and the overall quality of the current collection component 23 can be improved.

[0130] Please continue reading. Figure 9 In some embodiments, the first groove 251 is located on the surface of the second connector 232. The maximum groove depth of the first groove 251 along the first direction X is less than the thickness of the second connector 232.

[0131] Please continue reading. Figure 10 According to some embodiments of this application, at least a portion of the first groove 251 extends through the second connector 232 along the first direction X.

[0132] The surface of the second connector 232 includes a third surface 232A and a fourth surface 232B disposed opposite to each other, wherein at least one of the third surface 232A and the fourth surface 232B may be provided with a first groove 251.

[0133] In some embodiments, the third surface 232A is provided with at least one first groove 251, and the groove depth of any first groove 251 is less than the thickness of the second connector 232. When multiple first grooves 251 are provided on the third surface 232A, the groove depths of the multiple first grooves 251 may be the same or different.

[0134] In some embodiments, the fourth surface 232B is provided with at least one first groove 251, and the groove depth of any first groove 251 is less than the thickness of the second connector 232. When multiple first grooves 251 are provided on the fourth surface 232B, the groove depths of the multiple first grooves 251 may be the same or different.

[0135] In some embodiments, the first connector 231 and the second connector 232 are stacked along the first direction X. When the first surface 231A abuts against the third surface 232A, a first groove 251 is provided on both the third surface 232A and the fourth surface 232B. The first solder mark 241 can be intermittently provided or non-closed, such that the position of the notch 241A formed at the break of the first solder mark 241 corresponds to the position of the first groove 251. The first groove on the third surface 232A and the first groove on the fourth surface 232B can be completely staggered, partially overlapped, or completely opposite. It is understood that when partially overlapping or completely opposite, the sum of the groove depths of the first groove on the third surface 232A and the first groove on the fourth surface 232B is less than the thickness of the second connector 232.

[0136] The maximum groove depth being less than the thickness of the second connector 232 means that the maximum dimension of any first groove 251 extending along the first direction X is less than the thickness of the second connector 232. It can be understood that the thickness claimed here refers to the thickness of the component at the location of the first groove 251 along the first direction X.

[0137] Please continue reading. Figure 10 At least a portion of the first groove 251 penetrating the second connector 232 along the first direction X means that at least a portion of the first groove 251 has a dimension along the first direction X equal to the thickness of the second connector 232. That is, in some embodiments, the first groove 251 penetrating the second connector 232 along the first direction X and the first groove 251 not penetrating the second connector 232 can coexist. The first groove 251 penetrating the second connector 232 along the first direction X and the first groove 251 not penetrating the second connector 232 can be connected or independently configured; this embodiment does not impose any limitations on this.

[0138] By positioning the first groove 251 on the surface of the second connector 232 along the first direction X, and ensuring that the maximum groove depth of the first groove 251 is less than the thickness of the second connector 232, welding stress can be relieved while maintaining the structural strength of the second connector 232.

[0139] By making at least a portion of the first groove 251 penetrate the second connector 232 along the first direction X, the welding stress when welding the first connector 231 and the second connector 232 can be further relieved.

[0140] In some embodiments, both the first connector 231 and the second connector 232 are provided with a first groove 251. In a projection plane perpendicular to the first direction X, the orthographic projection of the first groove 251 provided on the first connector 231 is completely offset from the orthographic projection of the first groove 251 provided on the second connector 232.

[0141] The first connector 231 may have a first groove 251. This could be a first surface 231A of the first connector 231 having a non-penetrating first groove 251, or a second surface 231B of the first connector 231 having a non-penetrating first groove 251, or a first groove 251 penetrating the first connector 231 along the first direction X, or a combination of the above.

[0142] The second connector 232 may have a first groove 251 provided. This could be a first groove 251 that does not penetrate the third surface 232A of the second connector 232, or a first groove 251 that does not penetrate the fourth surface 232B of the second connector 232, or a first groove 251 that penetrates the second connector 232 along the first direction X, or a combination of the above.

[0143] In a projection plane perpendicular to the first direction X, the orthographic projection of the first groove 251 on the first connector 231 and the orthographic projection of the first groove 251 on the second connector 232 are completely offset, meaning that in a projection plane perpendicular to the first direction X, the orthographic projections of the first groove 251 on the first connector 231 and the first groove 251 on the second connector 232 do not overlap. Specifically, the non-overlapping of the orthographic projections of the first groove 251 on the first connector 231 and the first groove 251 on the second connector 232 in a projection plane perpendicular to the first direction X can also mean that the orthographic projections of the first groove 251 on the first connector 231 onto the first surface 231A and the first groove 251 on the second connector 232 onto the first surface 231A do not overlap. The non-overlapping of the orthographic projection of the first groove 251 on the first surface 231A and the orthographic projection of the first groove 251 on the second connector 232 on the first surface 231A can include: non-overlapping in the radial direction along the geometric center of the second connector 232, or non-overlapping in the circumferential direction along the geometric center of the second connector 232. Taking the second connector 232 as a disk shape as an example, the radial direction of the geometric center of the second connector 232 refers to the direction of the radius passing through the geometric center of the second connector 232. The circumferential direction of the geometric center of the second connector 232 refers to the circumferential direction of the second connector 232.

[0144] In some embodiments, the first connector 231 and the second connector 232 are stacked along the first direction X, and the first surface 231A and the third surface 232A are welded together. The first groove 251 is provided only on the second surface 231B and / or the fourth surface 232B. In the projection plane perpendicular to the first direction X, the orthographic projection of the first groove 251 on the first connector 231 is completely offset from the orthographic projection of the first groove 251 on the second connector 232, which can support the first solder mark 241 to have a continuous closed shape in the orthographic projection in the projection plane perpendicular to the first direction. However, in order to further alleviate the welding stress when welding the first connector 231 and the second connector 232, the first solder mark 241 can still be provided intermittently, that is, the first solder mark 241 is provided with a notch 241A, and in the projection plane perpendicular to the first direction X, the orthographic projection of the first groove 251 is at least partially provided within the orthographic projection of the notch 241A.

[0145] Because the base metals of the first connector 231 and the second connector 232 are different, the welding deformations of the first connector 231 and the second connector 232 are different when they are welded. By completely misaligning the orthographic projection of the first groove 251 on the first connector 231 with the orthographic projection of the first groove 251 on the second connector 232 in a projection plane perpendicular to the first direction X, the deformation differences between the first connector 231 and the second connector 232 when they are welded can be coordinated, so that the deformation shapes of the first connector 231 and the second connector 232 affected by welding stress have a certain degree of adaptability.

[0146] By providing a first groove 251 for both the first connector 231 and the second connector 232, and ensuring that the orthographic projection of the first groove 251 on the first connector 231 is completely offset from the orthographic projection of the first groove 251 on the second connector 232 in a projection plane perpendicular to the first direction X, the welding stress during welding of the first connector 231 and the second connector 232 can be further alleviated, and the deformation difference between the first connector 231 and the second connector 232 can be coordinated.

[0147] Please continue reading. Figure 12 In some embodiments, both the first connector 231 and the second connector 232 are provided with a first groove 251. In a projection plane perpendicular to the first direction X, the orthographic projection of the first groove 251 provided on the first connector 231 and the orthographic projection of the first groove 251 provided on the second connector 232 at least partially overlap.

[0148] The first groove 251 provided in the first connector 231 mentioned above can be a non-penetrating first groove 251 provided on the first surface 231A of the first connector 231, or a non-penetrating first groove 251 provided on the second surface 231B of the first connector 231, or a first groove 251 provided in the first connector 231 that penetrates the first connector 231 along the first direction X, or a combination of the above situations.

[0149] The first groove 251 provided in the second connector 232 as described above can be a non-penetrating first groove 251 provided on the third surface 232A of the second connector 232, or a non-penetrating first groove 251 provided on the fourth surface 232B of the second connector 232, or a first groove 251 provided in the second connector 232 that penetrates the second connector 232 along the first direction X, or a combination of the above situations.

[0150] In a projection plane perpendicular to the first direction X, the orthographic projection of the first groove 251 on the first connector 231 and the orthographic projection of the first groove 251 on the second connector 232 at least partially overlap may include: in a projection plane perpendicular to the first direction X, the orthographic projection of the first groove 251 on the first connector 231 and the orthographic projection of the first groove 251 on the second connector 232 completely coincide; or it may include in a projection plane perpendicular to the first direction X, the orthographic projection of the first groove 251 on the first connector 231 and the orthographic projection of the first groove 251 on the second connector 232 only partially overlap.

[0151] In a projection plane perpendicular to the first direction X, the orthographic projection of the first groove 251 on the first connector 231 and the orthographic projection of the first groove 251 on the second connector 232 overlap at least partially, which helps to reduce the impact of the first groove 251 on the welding area of ​​the first connector 231 and the second connector 232.

[0152] In some embodiments, the notch 241A of the first solder mark 241 is correspondingly disposed to the orthographic projection of the first groove 251 on a projection plane perpendicular to the first direction X. For example, it can be a one-to-one correspondence, or one notch 241A can be correspondingly disposed to multiple first grooves 251, that is, the orthographic projections of multiple first grooves 251 on a projection plane perpendicular to the first direction X are at least partially located within the orthographic projection range of one notch 241A.

[0153] In some embodiments, when the first connector 231 and the second connector 232 are stacked along the first direction X, and the first surface 231A and the third surface 232A are welded together, only when the first groove 251 is provided on the second surface 231B and / or the fourth surface 232B, in the projection plane perpendicular to the first direction, the orthographic projection of the first groove 251 on the first connector 231 and the orthographic projection of the first groove 251 on the second connector 232 at least partially overlap.

[0154] In some embodiments, when both the first connector 231 and the second connector 232 are provided with a first groove 251, the groove width of the first groove 251 provided on the first connector 231 is equal to the groove width of the first groove 251 provided on the second connector 232.

[0155] The slot width of the first groove 251 on the first connector 231 refers to the dimension of the first groove 251 on the first connector 231 along the direction perpendicular to the slot depth. The slot width of the first groove 251 on the first connector 231 can be greater than or equal to 0.1 times the thickness of the first connector 231, and less than or equal to 10 times the thickness of the first connector 231. For example, the slot width of the first groove 251 on the first connector 231 can be 0.1H, 0.2H, 0.3H, 0.5H, 0.8H, 1H, 1.5H, 2H, 2.5H, 3H, 4H, 5H, 6H, 7H, 8H, 9H, 9.5H, or 10H. Wherein, H represents the thickness of the first connector 231. By appropriately setting the groove width of the first groove 251 provided on the first connector 231, welding stress can be alleviated while ensuring sufficient welding area between the first connector 231 and the second connector 232. In some embodiments, the thickness of the first connector 231 is greater than or equal to 0.1 mm and less than or equal to 3 mm. For example, the thickness of the first connector 231 is equal to 0.5 mm, 1 mm, 1.5 mm, 2 mm, or 2.5 mm.

[0156] The slot width of the first groove 251 on the second connector 232 refers to the dimension of the first groove 251 on the second connector 232 along the direction perpendicular to the slot depth of the first groove 251. The width of the first groove 251 on the second connector 232 can be greater than or equal to 0.1 times the thickness of the second connector 232, and less than or equal to 10 times the thickness of the second connector 232. For example, the width of the first groove 251 on the second connector 232 can be 0.1h, 0.2h, 0.3h, 0.5h, 0.8h, 1h, 1.5h, 2h, 2.5h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 9.5h, or 10h. Here, h represents the thickness of the second connector 232. By appropriately setting the width of the first groove 251 on the second connector 232, welding stress can be alleviated while ensuring sufficient welding area between the first connector 231 and the second connector 232. In some embodiments, the thickness of the second connector 232 is greater than or equal to 0.1 mm and less than or equal to 3 mm. For example, the thickness of the second connector 232 is 0.5 mm, 1 mm, 1.5 mm, 2 mm, or 2.5 mm.

[0157] When the first connector 231 and the second connector 232 are welded together, and the first weld mark 241 is intermittently set due to the influence of the first groove 251, the width of either the first groove 251 on the first connector 231 or the first groove 251 on the second connector 232 will affect the welding area between the first connector 231 and the second connector 232. The larger the groove width, the smaller the area available for welding the first connector 231 and the second connector 232, and the greater the impact on welding reliability and electrical conductivity. When the first groove 251 on the first connector 231 corresponds to the first groove 251 on the second connector 232, the influence of the groove widths of the first groove 251 on the first connector 231 and the first groove 251 on the second connector 232 on the welding area depends on the larger of the two groove widths. At this time, making the groove width of the first groove 251 on the first connector 231 equal to the groove width of the first groove 251 on the second connector 232 can alleviate welding stress and reduce the impact of the groove width on the welding area.

[0158] When the first groove 251 on the first connector 231 does not correspond to the first groove 251 on the second connector 232, the groove width of the first groove 251 on the first connector 231 and the groove width of the first groove 251 on the second connector 232 will both affect the welding area.

[0159] By providing a first groove 251 for both the first connector 231 and the second connector 232, and ensuring that the orthographic projection of the first groove 251 on the first connector 231 and the orthographic projection of the first groove 251 on the second connector 232 at least partially overlap in a projection plane perpendicular to the first direction X, the welding stress between the first connector 231 and the second connector 232 can be relieved simultaneously, and the welding deformation of the first connector 231 and the second connector 232 can be suppressed.

[0160] Please see Figure 12 In some embodiments, the first solder mark 241 is provided with a plurality of notches 241A, which break the first solder mark 241 to form a plurality of sub-solder marks 2411. In a projection plane perpendicular to the first direction X, the orthographic projection of any first groove 251 is at least partially disposed within the orthographic projection of the notch 241A between two adjacent sub-solder marks 2411.

[0161] The phrase "multiple notches 241A break the first solder mark 241 to form multiple sub-solder marks 2411" means that the first solder mark 241 includes at least two sub-solder marks 2411. That is, the first solder mark 241 has at least two notches 241A.

[0162] It should be noted that in some other embodiments of this application, the first solder mark 241 may also have only one notch 241A. In this case, the orthographic projection of the first solder mark 241 in the projection plane perpendicular to the first direction X is a continuous, non-closed shape.

[0163] In a projection plane perpendicular to the first direction X, the orthographic projections of multiple notches 241A and multiple sub-solder marks 2411 are alternately arranged circumferentially along the geometric center of the orthographic projection of the second connector 232. The orthographic projection of any first groove 251 is at least partially disposed within the orthographic projection of the notch 241A between two adjacent sub-solder marks 2411, such that in a projection plane perpendicular to the first direction X, in the circumferential direction along the geometric center of the orthographic projection of the second connector 232, the orthographic projections of a sub-solder mark 2411 are respectively located on both sides of the orthographic projection of the first groove 251, and the orthographic projection of the first groove 251 and the orthographic projection of the notch 241A at least partially overlap.

[0164] In some embodiments, in a projection plane perpendicular to the first direction X, the orthographic projections of the multi-pass solder marks 2411 are equally spaced circumferentially along the geometric center of the orthographic projection of the second connector 232 to uniformly alleviate welding stress.

[0165] By providing multiple notches 241A to the first weld mark 241, the multiple notches 241A break the first weld mark 241 to form multiple sub-weld marks 2411. In the projection plane perpendicular to the first direction X, the orthographic projection of any first groove 251 is at least partially disposed within the orthographic projection of the notch 241A between two adjacent sub-weld marks 2411, so as to further alleviate welding stress and reduce the probability of deformation of the current collector 23.

[0166] Please continue reading. Figure 12 In some embodiments, in a projection plane perpendicular to the first direction X, the sum of the central angles α formed by the geometric centers of the orthographic projection of the first solder mark 241 relative to the orthographic projection of the second connector 232 satisfies: 210°≤α<360°, preferably 250°≤α≤350°.

[0167] Taking the second connector 232 as a disk shape as an example, in the projection plane perpendicular to the first direction X, the sum of the central angles α formed by the geometric center of the orthographic projection of the first solder mark 241 relative to the orthographic projection of the second connector 232 refers to the central angle corresponding to the length of the orthographic projection of the first solder mark 241 in the projection plane perpendicular to the first direction X.

[0168] Taking the first solder mark 241, which includes four sub-solder marks 2411, as an example, in the projection plane perpendicular to the first direction X, the central angles formed by the geometric centers of the orthographic projections of the four sub-solder marks 2411 relative to the orthographic projection of the second connector 232 are α1, α2, α3, and α4, respectively. Therefore, in the projection plane perpendicular to the first direction X, the sum of the central angles formed by the geometric centers of the orthographic projections of the first solder mark 241 relative to the orthographic projection of the second connector 232 is α = α1 + α2 + α3 + α4. Here, α1, α2, α3, and α4 can be the same or different.

[0169] In some embodiments, in a projection plane perpendicular to the first direction X, the sum of the central angles α formed by the geometric centers of the orthographic projection of the first solder mark 241 relative to the orthographic projection of the second connector 232 can be equal to 210°, 220°, 2130°, 240°, 250°, 260°, 270°, 280°, 290°, 300°, 310°, 320°, 330°, 340°, 350°, 355°, or any other value between any two of the above values.

[0170] The longer the first weld mark 241, the larger the sum of the central angles α formed by the geometric centers of the orthographic projection of the first weld mark 241 relative to the orthographic projection of the second connector 232 in the projection plane perpendicular to the first direction X. The larger the flow area of ​​the first electrode 211 welded to the current collector 23 is. Therefore, in order to relieve welding stress while meeting the flow requirements, the sum of the central angles α formed by the geometric centers of the orthographic projection of the first weld mark 241 relative to the orthographic projection of the second connector 232 in the projection plane perpendicular to the first direction X can satisfy: 250°≤α≤350°.

[0171] In the projection plane perpendicular to the first direction X, the sum of the central angles α formed by the geometric centers of the orthographic projection of the first solder mark 241 relative to the orthographic projection of the second connector 232 satisfies the set numerical range, which can alleviate welding stress while increasing the flow area of ​​the solder mark.

[0172] Please continue reading. Figure 12 In some embodiments, the second connector 232 includes a first portion 2321 and a second portion 2322. The first portion 2321 is located in the central region of the second connector 232 and is used for welding to the first tab 211. The second portion 2322 surrounds the outer periphery of the first portion 2321 and is used for welding to the first connector 231.

[0173] The second part 2322 is located around the first part 2321 and is welded to the first connector 231, such that the welding positions of the second connector 232 and the first connector 231 and the first connector 232 and the first tab 211 are staggered.

[0174] In some embodiments, the first part 2321 and the second part 2322 may be coplanar flat plates to reduce the amount of processing required for the second connector 232 and reduce manufacturing costs. The first part 2321 and the second part 2322 can be formed in one step.

[0175] By having the second part 2322 surround the outer periphery of the first part 2321 and weld the second part 2322 to the first connector 231, the welding areas of the current collector 23 and the first tab 211 and the first electrode lead-out part 22A can be separated. This helps to reduce the welding influence between the welding of the second connector 232 and the first connector 231 and the welding of the second connector 232 and the first tab 211, and alleviates welding deformation.

[0176] Please continue reading. Figure 5 , Figures 7-12According to some embodiments of this application, the first connector 231 includes a hollow area 231C located in the central region. The first connector 231 and the second connector 232 are stacked along a first direction X, and the first part 2321 is directly opposite the hollow area 231C.

[0177] Please continue reading. Figures 6 to 11 According to some embodiments of this application, the first connector 231 includes a hollow area 231C located in the central region. The first connector 231 and the second connector 232 are mated along a second direction Y, and the second connector 232 is located within the hollow area 231C. The second direction Y is perpendicular to the thickness direction of the second connector 232.

[0178] The hollow area 231C can be a through hole extending through the first connector 231 along the first direction X. The shape of the hollow area 231C can be any closed shape formed by at least one of straight lines and curves, including but not limited to oval holes, square holes, and circular holes. The hollow area 231C can be located in the central region of the first connector 231, making the first connector 231 approximately annular plate structure.

[0179] The first part 2321 and the hollow area 231C are positioned opposite each other, meaning that the orthographic projection of the hollow area 231C on the second connector 232 coincides with the first part 2321. After the first connector 231 and the second connector 232 are welded, the hollow area 231C exposes the first part 2321, which is beneficial for the welding between the first part 2321 and the first tab 211.

[0180] The second connector 232 being located within the cutout area 231C means that the first connector 231 is located around the second connector 232. After the first connector 231 and the second connector 232 are welded, the cutout area 231C exposes the second connector 232.

[0181] In some embodiments, the second connector 232 is disc-shaped, and the first connector 231 is annular. The inner diameter of the first connector 231 is greater than or equal to the outer diameter of the second connector 232. Thus, the disc-shaped second connector 232 can be arranged within the hollow area 231C of the first connector 231, and the outer surface of the second connector 232 can be welded to the inner surface of the first connector 231 by butt welding.

[0182] By stacking the first connector 231 and the second connector 232 along the first direction X, and with the first part 2321 facing the hollow area 231C, it is more conducive to realizing the welding process of the first connector 231 and the first tab 211, which is beneficial to improving welding efficiency and welding quality.

[0183] By aligning the first connector 231 and the second connector 232 along the second direction Y, with the second connector 232 located within the hollow area 231C, the overall height of the current collector 23 can be reduced. At the same time, the staggered arrangement of the first connector 231 and the second connector 232 allows the solder marks to be staggered, thereby reducing the influence between them during welding and improving the welding quality of the battery cells.

[0184] Please continue reading. Figures 7-8 According to some embodiments of this application, the first connector 231 is a closed ring, and a plurality of first grooves 251 disposed on the first connector 231 are spaced apart circumferentially along the geometric center of the first connector 231.

[0185] The geometric center of the first connector 231 refers to its centroid. The multiple first grooves 251 spaced apart circumferentially along the geometric center of the first connector 231 means that multiple first grooves 251 are arranged along the circumferential direction surrounding the centroid of the first connector 231, and the multiple first grooves 251 are spaced apart. That is, multiple first grooves 251 are spaced apart along the circumference of the first connector 231.

[0186] The number of slot 251 is greater than or equal to 1. For example, the number of slot 251 in the first slot is 2, 4 or 6, etc.

[0187] In some embodiments, to balance the relationship between the structural strength of the first connector 231 and the effect of relieving welding stress, the first groove 251 may be configured as four.

[0188] Multiple first grooves 251 may be arranged at equal intervals to uniformly relieve welding stress on the first connector 231.

[0189] By circumferentially spacing multiple first grooves 251 along the geometric center of the first connector 231, the stress on the first connector 231 is further relieved when welding the first connector 231 and the second connector 232, thereby reducing the deformation of the current collection member 23 and the probability of welding defects.

[0190] According to some embodiments of this application, any of the first grooves 251 disposed on the first connector 231 extends radially along the geometric center of the first connector 231.

[0191] Taking the first connector 231 as an example (which is annular), the radial direction of the geometric center of the first connector 231 refers to the direction of the radius passing through the geometric center of the first connector 231. The first groove 251 can extend radially along the geometric center of the first connector 231 in a straight line towards the geometric center of the first connector 231. Alternatively, the first groove 251 can also extend in a curved manner, such as extending radially outward towards the geometric center of the first connector 231 in a wavy line shape.

[0192] By extending the first groove 251 radially along the geometric center of the first connector 231, the extension direction of the first groove 251 can intersect with the extension direction of the solder mark, thereby better releasing welding stress and improving the incoming material quality of the current collector 23.

[0193] Please continue reading. Figure 13 , Figure 13 This is a schematic diagram of the structure of another first connector according to some embodiments of this application.

[0194] According to some embodiments of this application, the extension direction of the first groove 251 disposed on the first connector 231 intersects the extension direction of the first connector 231, and at least one first groove 251 is configured to completely disconnect the first connector 231.

[0195] The extension direction of the first groove 251 provided on the first connector 231 intersects the extension direction of the first connector 231, and at least one first groove 251 is configured to completely disconnect the first connector 231, meaning that the solid portion of the first connector 231 is discontinuous due to the presence of the first groove 251. The solid portion of the first connector 231 refers to the part of the first connector 231 without the hollow area 231C and the first groove 251. Therefore, the presence of the first groove 251 can make the solid portion of the first connector 231 discontinuous, thereby forming a free edge that can be used for stress relief.

[0196] In some embodiments, the first connector 231 is divided into multiple segments at equal intervals by the first groove 251 to uniformly relieve welding stress.

[0197] By making the extension direction of the first groove 251 provided on the first connector 231 intersect with the extension direction of the first connector 231, and at least one of the first grooves 251 is configured to completely disconnect the first connector 231, a space for releasing welding stress is provided for the first connector 231 when welding the first connector 231 and the second connector 232, thereby further alleviating the deformation and cracks of the current collector 23 caused by the difference in deformation between the first connector 231 and the second connector 232, thereby improving the incoming material quality of the current collector 23, and further improving the connection quality between the current collector 23 and the first tab 211 and the first electrode lead-out portion 22A.

[0198] Please continue reading. Figure 14 , Figure 14 This is a schematic diagram of the structure of another second connector according to some embodiments of this application.

[0199] According to some embodiments of this application, the first groove 251 disposed on the second connector 232 is located in the second part 2322 of the second connector 232.

[0200] The first groove 251 disposed on the second connector 232 located in the second part 2322 of the second connector 232 may include: the first groove 251 disposed on the second connector 232 extends radially along the geometric center of the second connector 232 and penetrates the second part 2322; or the first groove 251 disposed on the second connector 232 extends radially along the geometric center of the second connector 232, but does not penetrate the second part 2322.

[0201] By providing a first groove 251 on the second part 2322 of the second connector 232, the welding stress on the second connector 232 can be relieved when welding the first connector 231 and the second connector 232, and the deformation of the second connector 232 caused by welding can be reduced.

[0202] Please continue reading. Figure 14 In some embodiments, a plurality of first grooves 251 disposed on the second connector 232 extend radially along the geometric center of the second connector 232 and are spaced circumferentially along the geometric center of the second connector 232.

[0203] The geometric center of the second connector 232 refers to its centroid. The multiple first grooves 251 spaced circumferentially around the geometric center of the second connector 232 mean that multiple first grooves 251 are arranged along the circumferential direction surrounding the centroid of the second connector 232, and these multiple first grooves 251 are spaced apart. For example, if the second connector 232 is disc-shaped, the multiple first grooves 251 are spaced apart along the circumference of the second connector 232.

[0204] Taking the second connector 232 as a disk shape as an example, the radial direction of the geometric center of the second connector 232 refers to the direction of the radius passing through the geometric center of the second connector 232. The first groove 251 can extend radially along the geometric center of the second connector 232 in a straight line towards the geometric center of the second connector 232. Alternatively, the first groove 251 can also extend in a curved manner, such as extending radially outward towards the geometric center of the second connector 232 in a wavy form.

[0205] In the direction extending radially along the geometric center of the second connector 232, the length of the first groove 251 can be greater than or equal to the length of the second part 2322. That is, the boundary of the first groove 251 extending radially along the geometric center of the second connector 232 can correspond to the boundary of the first part 2321 and the boundary of the second part 2322, or it can be located within the boundary of the second part 2322. The radial extension of the first groove 251 along the geometric center of the second connector 232 can also extend into the first part 2321, so that the boundary of the first groove 251 extending radially along the geometric center of the second connector 232 is located within the first part 2321.

[0206] In some embodiments, the second connector 232 is disk-shaped, and the length of the first groove 251 in a direction extending radially along the geometric center of the second connector 232 can be greater than or equal to 1 / 6 times the radius of the second connector 232, and less than or equal to 5 / 6 times the radius of the second connector 232. For example, the length of the first groove 251 is 1 / 6r, 1 / 3r, or 1 / 2r, etc., where r represents the radius of the second connector 232.

[0207] By making a plurality of first grooves 251 provided on the second connector 232 extend radially along the geometric center of the second connector 232 and are spaced circumferentially along the geometric center of the second connector 232, the stress on the second connector 232 is further relieved when welding the first connector 231 and the second connector 232, the deformation of the current collecting member 23 and the probability of welding defects are reduced, and the influence of the first grooves 251 on the subsequent welding of the second connector 232 is reduced.

[0208] Please continue reading. Figures 9-12 and Figure 14 According to some embodiments of this application, the first part 2321 of the second connector 232 further includes a second groove 252. The second groove 252 extends through the second connector 232 along a first direction X, or the groove depth of the second groove 252 along the first direction X is less than the thickness of the second connector 232.

[0209] The second groove 252 is a groove that may or may not penetrate the first portion 2321 along the first direction X. In some examples, the second groove 252 that does not penetrate may be formed by stamping the first portion 2321 of the second connector 232.

[0210] In some embodiments, at least one of the third surface 232A and the fourth surface 232B is provided with a second groove 252.

[0211] It should be noted that in some embodiments, the first part 2321 of the second connector 232 may not have a second slot 252.

[0212] By providing a second groove 252 on the first part 2321, stress release space can be provided for welding stress when welding the second connector 232 and the first electrode lug 211, reducing the probability of welding deformation of the current collector 23.

[0213] Please continue reading. Figures 9-12 and Figure 14 According to some embodiments of this application, at least one second groove 252 extends in a direction that coincides with the extension direction of the first groove 251 disposed on the second connector 232, and both extend radially along the geometric center of the second connector 232.

[0214] Taking the second connector 232 as a disc shape as an example, the extension direction of the second groove 252 coincides with the extension direction of the first groove 251 provided on the second connector 232, and both extend radially along the geometric center of the second connector 232. This can mean that the second groove 252 and the first groove 251 provided on the second connector 232 both extend along the radial direction of the second connector 232.

[0215] The first groove 251 provided on the second connector 232 can be a straight line, a curve, or a continuous shape formed by multiple straight lines and / or curves in its extension direction. The second groove 252 can be a straight line, a curve, or a continuous shape formed by multiple straight lines and / or curves in its extension direction.

[0216] By aligning the extension direction of at least one second groove 252 with the extension direction of the first groove 251 provided on the second connector 232, and both extending radially along the geometric center of the second connector 232, the mutual influence between the preceding and following welding processes can be reduced, and welding stress deformation can be alleviated.

[0217] Please continue reading. Figures 9-12 and Figure 14 According to some embodiments of this application, at least one second groove 252 extends in a different direction than the first groove 251 disposed on the second connector 232.

[0218] Taking the second connector 232 as a disc as an example, the extension direction of the second groove 252 is different from the extension direction of the first groove 251 provided on the second connector 232. This can mean that along the circumference of the second connector 232, the second groove 252 and the first groove 251 provided on the second connector 232 are alternately arranged.

[0219] In some embodiments, the second groove 252 and the first groove 251 disposed on the second connector 232 are equally spaced along the circumferential direction of the geometric center of the second connector 232.

[0220] By making the extension direction of at least one second groove 252 different from the extension direction of the first groove 251 provided on the second connector 232, the stress during welding of the first connector 231 and the second connector 232 can be relieved, as well as the stress during welding of the second connector 232 and the first tab 211.

[0221] Please continue reading. Figures 9-12 and Figure 14 According to some embodiments of this application, the number of second grooves 252 is multiple, and the multiple second grooves 252 are arranged circumferentially at intervals along the geometric center of the second connector 232.

[0222] The number of second slots 252 can be greater than or equal to 1. Taking the second connector 232 as a disc as an example, the multiple second slots 252 arranged circumferentially along the geometric center of the second connector 232 means that the multiple second slots 252 are spaced apart along the circumferential direction of the second connector 232.

[0223] In some embodiments, the plurality of second grooves 252 may be evenly spaced to make the deformation at various points on the second connector 232 similar when the second connector 232 is welded to the first tab 211.

[0224] By circumferentially spacing multiple second grooves 252 along the geometric center of the second connector 232, the stress during welding of the second connector 232 and the first electrode 211 is further relieved, the deformation of the current collector 23 is reduced, and the welding quality of the current collector 23 and the first electrode 211 is improved.

[0225] Please continue reading. Figures 9-12 and Figure 14 According to some embodiments of this application, the number of second slots 252 is multiple, and at least two second slots 252 have different extension lengths.

[0226] For example, the second slot 252 includes a first slot 2521 and a second slot 2522. The first slot 2521 extends radially along the geometric center of the second connector 232. The second slot 2522 extends radially along the geometric center of the second connector 232 and is offset from the first slot 2521, circumferentially spaced along the geometric center of the second connector 232. The radial extension length of the first slot 2521 along the geometric center of the second connector 232 is greater than the radial extension length of the second slot 2522 along the geometric center of the second connector 232. Both the first slot 2521 and the second slot 2522 are slots that penetrate or do not penetrate the first part 2321 along the thickness direction. The extension shape of the first slot 2521 and the second slot 2522 can be a straight line, a curve, or a continuous combination of multiple straight lines or curves.

[0227] Taking the second connector 232 as a disk shape as an example, the second slot 2522 extending radially along the geometric center of the second connector 232 can mean that the second slot 2522 extends radially along the radius of the second connector 232. The radial extension length of the first slot 2521 along the geometric center of the second connector 232 refers to the length of the first slot 2521 extending radially along the radius of the second connector 232. The radial extension length of the second slot 2522 along the geometric center of the second connector 232 refers to the length of the second slot 2522 extending radially along the radius of the second connector 232. The second slot 2522 and the first slot 2521 being offset from each other along the circumferential direction of the geometric center of the second connector 232 can mean that the second slot 2522 and the first slot 2521 are offset from each other along the circumference of the second connector 232.

[0228] In some embodiments, the second slot 2522 is offset from the first slot 2521 and is uniformly spaced along the circumferential direction of the geometric center of the second connector 232.

[0229] In some embodiments, at least one of the first slot 2521 and the second slot 2522 has a radial extension length along the geometric center of the second connector 232 that is greater than or equal to 1 / 6 times the radius of the second connector 232 and less than or equal to 5 / 6 times the radius of the second connector 232, in order to balance the relationship between the welding area and the effect of relieving welding stress.

[0230] In some embodiments, the number of first slots 2521 is multiple and they are arranged in pairs, and the extension direction of any pair of first slots 2521 coincides with a straight line passing through the geometric center of the second connector 232; and / or, the number of second slots 2522 is multiple and they are arranged in pairs, and the extension direction of any pair of second slots 2522 coincides with a straight line passing through the geometric center of the second connector 232.

[0231] The presence of multiple first slots 2521 arranged in pairs indicates that the number of first slots 2521 can be even. For example, the number of first slots 2521 can be 2, 4, or 8. The extension direction of the paired first slots 2521 coincides with the straight line passing through the geometric center of the second connector 232. For example, if the second connector 232 is disc-shaped, the paired first slots 2521 extend along the diameter direction of the second connector 232.

[0232] The presence of multiple second slots 2522 arranged in pairs indicates that the number of second slots 2522 can be even. For example, the number of second slots 2522 can be 2, 4, or 8, etc. The extension direction of the paired second slots 2522 coincides with the straight line passing through the geometric center of the second connector 232. For example, if the second connector 232 is disc-shaped, the paired second slots 2522 extend along the diameter direction of the second connector 232.

[0233] By arranging the first slot 2521 in pairs with respect to the geometric center of the second connector 232, and / or arranging the second slot 2522 in pairs with respect to the geometric center of the second connector 232, the stress effects during welding of the second connector 232 and the first tab 211 can be alleviated relatively evenly, which is beneficial to alleviating the problem of deformation of the current collector 23 caused by welding.

[0234] In some embodiments, the number of second slots 2522 is the same as the number of first slots 251 provided on the second connector 232, and they are arranged in a one-to-one correspondence. Each second slot 2522 and each first slot 251 on the second connector 232 are located on the same side of the geometric center of the second connector 232 and extend in the same direction. This facilitates welding positioning between the first connecting portion 231 and the second connecting portion 232, and between the second connecting portion 232 and the first electrode tab 211, reduces the mutual influence between preceding and following welding processes, alleviates welding stress deformation, and improves the overall welding quality.

[0235] The one-to-one correspondence between the first groove 251 and the second slot 2522 on the second connector 232 means that each second slot 2522 is directly opposite a first groove 251 in the radial direction along the geometric center of the second connector 232. Each second slot 2522 and its opposite first groove 251 are located on the same side of the geometric center of the second connector 232. The same extension direction of the first groove 251 and the second slot 2522 means that both the first groove 251 and the second slot 2522 extend radially along the geometric center of the second connector 232.

[0236] By setting a second groove 252 of different lengths, the second connector 232 forms an asymmetrical groove. This facilitates the welding positioning between the first connector 231 and the second connector 232, and also reduces the overall warping of the second connector 232 caused by welding deformation. This reduces the deformation when the second connector 232 and the first connector 231 are combined, which is beneficial to improving the subsequent welding quality of the current collector.

[0237] Please continue reading. Figures 9-12 and Figure 14According to some embodiments of this application, the second connector 232 is provided with a central through hole 232C, and one end of at least one second groove 252 is connected to the central through hole 232C.

[0238] The central through hole 232C is a hole located at the geometric center of the second connector 232 and extending through the second connector 232 along the thickness direction.

[0239] In some embodiments, the second slot 2522 and the first slot 2521 may be connected to or not connected to the central through hole 232C, respectively.

[0240] By providing a central through hole 232C on the second connector 232, and having at least one end of a second groove 252 connected to the central through hole 232C, welding stress can be relieved while facilitating welding positioning when welding the second connector 232 and the first tab 211.

[0241] Please continue reading. Figure 14 In some embodiments, both the second groove 252 and the first groove 251 disposed on the second connector 232 extend radially along the geometric center of the second connector 232. Furthermore, along the extension direction of either the second groove 252 or the first groove 251, the ratio k of the effective length of the ungrooved portion from the geometric center to the outer edge of the second connector 232 to the total length from the geometric center to the outer edge of the second connection portion satisfies: 1 / 6 ≤ k ≤ 5 / 6.

[0242] Taking the second connector 232 as a disc shape as an example, both the second groove 252 and the first groove 251 disposed on the second connector 232 extend radially along the geometric center of the second connector 232, and both extend along the radial direction of the second connector 232. Along the extension direction of any second groove 252 or any first groove 251, the total length of the second connector 232 from its geometric center to its outer edge refers to the length of the second connector 232 along the radial direction. Along the extension direction of any second groove 252 or any first groove 251, the effective length of the second connector 232 from its geometric center to its outer edge without grooves refers to the remaining length obtained by subtracting the length of the second groove 252 and the length of the third groove from the radius of the second connector 232 along the radial direction of the second connector 232.

[0243] Along the extension direction of any second groove 252 or any first groove 251, the ratio k of the effective length of the second connector 232 from the geometric center to the outer edge without grooves to the total length of the second connection from the geometric center to the outer edge is the remaining length obtained by subtracting the length of the second groove 252 and the length of the third groove from the radius of the second connector 232. The ratio of this remaining length to the radius of the second connector 232 is greater than or equal to 1 / 6 and less than or equal to 5 / 6.

[0244] By specifically setting the ratio of the effective length of the ungrooved portion between the geometric center and the outer edge of the second connector 232 to the total length between the geometric center and the outer edge of the second connection portion, the second connector 232 can have a sufficient welding area when welding with the first electrode 211, while also taking into account the structural strength of the current collector 23 itself, reducing the amount of welding deformation, and thus improving the welding quality between the current collector 23 and the first electrode 211.

[0245] Please continue reading. Figure 4 In some embodiments, the first electrode lead-out portion 22A is welded to the first connector 231 to form a second solder mark 242, and the orthographic projection of the second solder mark 242 on the current collector 23 is offset from the first solder mark 241.

[0246] The first electrode lead-out portion 22A is connected to the first connector 231 through the second solder mark 242. The second solder mark 242 is orthogonally projected onto the current collector 23 and is offset from the first solder mark 241, meaning that the orthogonal projection of the second solder mark 242 onto the current collector 23 does not overlap with the first solder mark 241.

[0247] By setting the orthographic projection of the second solder mark 242 connecting the first electrode lead-out portion 22A and the first connector 231 on the current collector component to be offset from the first solder mark 241, the area where the first connector 231 is welded to the second connector 232 and the area where the first connector 231 is welded to the first electrode lead-out portion 22A can be distinguished. This helps to reduce the welding impact when welding the second connector 232 to the first connector 231 and welding the first connector 231 to the first electrode lead-out portion 22A, and alleviates welding deformation.

[0248] According to some embodiments of this application, the base metal of the second connector 232 is copper; the base metal of the first connector 231 is steel or aluminum.

[0249] In some embodiments, the first tab 211 is made of copper, and the base metal of the second connector 232 can be the same as that of the first tab 211, both being made of copper.

[0250] The base metal of the first connector 231 can be the same material as the first electrode lead-out portion 22A. In some examples, the first electrode lead-out portion 22A is the housing 221 or end cap 222 of the battery cell 20, and its material is steel or aluminum.

[0251] By making the base metal of the second connector 232 copper and the base metal of the first connector 231 steel or aluminum, it is possible to better adapt to subsequent welding processes and improve the overall quality of the battery.

[0252] Please continue reading. Figure 15 , Figure 15This is a schematic diagram of the structure of the first connector and the second connector in some embodiments of this application.

[0253] According to some embodiments of this application, the first connector 231 includes a first metal layer 2311 and a first flux layer 2312, wherein the first flux layer 2312 is disposed on at least one side of the surface of the first metal layer 2311.

[0254] According to some embodiments of this application, the second connector 232 includes a second metal layer 2323 and a second flux layer 2324, the second flux layer 2324 being located on at least one side of the surface of the second metal layer 2323.

[0255] A flux layer helps reduce welding defects. Especially when welding dissimilar materials, applying a flux layer to the surface of the welding materials can effectively reduce welding defects and the risk of incomplete welds or weld cracks.

[0256] The first flux layer 2312 is disposed on the surface of the first metal layer 2311, such that the first flux layer 2312 and the first metal layer 2311 are two parts stacked together along the thickness direction of the first connector 231. In one example, the first flux layer 2312 may be a nickel plating layer formed by electroplating.

[0257] In some embodiments, the first flux layer 2312 is disposed on the surface of the first metal layer 2311 facing the first electrode lead-out portion 22A. In other embodiments, at least a portion of the first flux layer 2312 is disposed on the surface of the first metal layer 2311 facing the second connector 232 to improve the welding quality of the first connector 231 and the second connector 232. In still other embodiments, the first flux layer 2312 is disposed on both sides of the first metal layer 2311 along its thickness direction.

[0258] The second flux layer 2324 and the second metal layer 2323 are two parts stacked together along the thickness direction of the second connection portion 231. The second flux layer 2324 can be formed on at least one side of the surface of the second metal layer 2323 by electroplating. The second metal layer 2323 can be plated with flux layer on its entire surface, or, depending on the specific welding position and material, flux layer can be plated on the surface of the area where the welding position is located to facilitate welding.

[0259] In some embodiments, a second flux layer 2324 is disposed on the surface of the second metal layer 2323 facing the first tab 211 to improve the welding quality between the second connector 232 and the first tab 211. In other embodiments, at least a portion of the second flux layer 2324 is disposed on the surface of the second metal layer 2323 facing the first connector 231 to improve the welding quality between the first connector 231 and the second connector 232. In still other embodiments, the second flux layer 2324 is disposed on both sides of the second metal layer 2323 along its thickness direction.

[0260] By providing a flux layer on the surface of at least one of the first metal layer 2311 and the second metal layer 2323, welding defects caused by differences in material welding performance can be mitigated, and the welding quality inside the current collector 23 or the welding quality between it and external components can be improved.

[0261] In some embodiments, such as Figure 3 and Figure 4 As shown, the electrode assembly 21 also includes a second electrode 212 with a polarity different from that of the first electrode 211; the first electrode 211 and the second electrode 212 are located at both ends of the electrode assembly 21 along the first direction X.

[0262] The housing assembly 22 includes a housing 221 and an end cap 222. The housing 221 forms a receiving space for accommodating the electrode assembly 21. The housing 221 includes an end wall 2212 located at one end of the receiving space and an opening located at the other end of the receiving space. The end cap 222 is connected to the housing 221 to close the opening. The first electrode lead-out portion 22A is either the housing 221 or the end cap 222.

[0263] The housing assembly 22 also includes a second electrode lead-out portion 22B, which passes through the end wall 2212 and is electrically connected to the second electrode tab 212.

[0264] The second electrode lead-out portion 22B can be an electrode post, and the end wall 2212 is provided with a mounting hole. The second electrode lead-out portion 22B is insulated from the mounting hole on the end wall 2212 by an insulating member. The part of the second electrode lead-out portion 22B located in the receiving space is electrically connected to the second electrode tab 212 so that the current of the second electrode tab 212 can be conducted to the outside of the housing assembly 22 through the second electrode lead-out portion 22B.

[0265] By electrically connecting the second electrode lead-out portion 22B to the second electrode tab 212, the current of the second electrode tab 212 can be conducted to the outside of the housing assembly 22 through the second electrode lead-out portion 22B.

[0266] The second aspect of this application also provides a battery 100, such as Figure 2 As shown, it includes the battery cell 20 in the above embodiment.

[0267] It is understood that the battery 100 provided in this application, by using any of the aforementioned battery cells 20, has all the beneficial effects of the aforementioned battery cells 20, which will not be elaborated here.

[0268] An embodiment of the third aspect of this application provides an electrical device that includes the battery 100 described in the above embodiments, the battery 100 being used to provide electrical energy.

[0269] Electrical devices include vehicles (such as cars, electric vehicles, ships, spacecraft, etc.), display devices (such as mobile phones, tablets, laptops, etc.), electric toys, power tools, etc.

[0270] It is understood that the electrical device provided in this application, by using any of the aforementioned batteries 100, has all the beneficial effects of the aforementioned batteries 100, which will not be repeated here.

[0271] An embodiment of the fourth aspect of this application provides an energy storage device, which includes the battery 100 in the above embodiments, the battery 100 being used to store electrical energy and provide electrical energy.

[0272] Energy storage devices can include, but are not limited to, centralized energy storage devices (such as containerized energy storage devices), distributed energy storage devices, mobile energy storage devices, wearable energy storage devices, and so on.

[0273] It is understood that the energy storage device provided in this application, by using any of the aforementioned batteries 100, has all the beneficial effects of the aforementioned batteries 100, which will not be elaborated here.

[0274] The following description, in conjunction with a specific embodiment, further illustrates the battery cell of this application.

[0275] The battery cell 20 provided in this application embodiment includes an electrode assembly 21, a housing assembly 22, and a current collector 23.

[0276] The electrode assembly 21 includes a first tab 211 and a second tab 212 that protrude along a first direction X.

[0277] The housing assembly 22 is used to house the electrode assembly 21. The housing assembly 22 includes a first electrode lead-out portion 22A and a second electrode lead-out portion 22B. The first electrode lead-out portion 22A is connected to the first electrode tab 211 through the current collector 23, and the second electrode lead-out portion 22B is electrically connected to the second electrode tab 212.

[0278] The current collector 23 includes a first connector 231 and a second connector 232. The base metals of the first connector 231 and the second connector 232 are different, and they are stacked along a first direction. The first connector 231 is welded to the first electrode lead-out portion 22A, and the second connector 232 is welded to the first electrode tab 211. The first connector 231 and the second connector 232 are welded to form a first solder mark 241. The first solder mark 241 has multiple notches 241A, which break the first solder mark 241 to form multiple sub-solder marks 2411.

[0279] The first connector 231 includes a hollow area 231C and a plurality of first grooves 251 communicating with the hollow area 231C. The plurality of first grooves 251 are circumferentially spaced along the geometric center of the first connector 231. Any first groove 251 penetrates the first connector 231 along the thickness direction so that the first connector 231 is disconnected.

[0280] The second connector 232 includes a first part 2321 and a second part 2322. The first part 2321 is located in the central region of the second connector 232 and is correspondingly disposed with respect to the hollowed-out area 231C. The first part 2321 is welded to the first tab 211. The second part 2322 surrounds the outer periphery of the first part 2321 and is welded to the first connector 231.

[0281] The second part 2322 of the second connector 232 is provided with a first groove 251 extending through the second connector 232 along the first direction X. The first groove 251 extends radially along the geometric center of the second connector 232. In a projection plane perpendicular to the first direction X, the orthographic projection of the first groove 251 provided on the first connector 231 at least partially overlaps with the orthographic projection of the first groove 251 provided on the second connector 232.

[0282] The first part 2321 of the second connector 232 is provided with a second groove 252 penetrating the second connector 232 along a first direction X. The second groove 252 extends radially along the geometric center of the second connector 232. The second groove 252 includes first slot holes 2521 and second slot holes 2522 that are circumferentially offset along the geometric center of the second connector 232. The radial extension length of the first slot holes 2521 along the geometric center of the second connector 232 is greater than the radial extension length of the second slot holes 2522 along the geometric center of the second connector 232. The number of second slot holes 2522 is the same as the number of first grooves 251 provided on the second connector 232 and they are arranged in a one-to-one correspondence. The extension direction of the paired first slot holes 2521 coincides with the straight line passing through the geometric center of the second connector 232, and the extension direction of the paired second slot holes 2522 coincides with the straight line passing through the geometric center of the second connector 232.

[0283] In a projection plane perpendicular to the first direction X, the orthographic projection of any first groove 251 is at least partially located within the orthographic projection of the notch 241 between two adjacent sub-soldering marks 2411, and the first direction X is parallel to the thickness direction of the second connector 232.

[0284] In this embodiment, by providing a first groove 251 for the first connector 231 and the second connector 232 of the current collector 23, and a second groove 252 for the second connector 232, and providing a notch 241A for the first solder mark 241, space can be provided for releasing welding stress when welding the first connector 231 and the second connector 232, as well as when welding the second connector 232 to the first electrode tab 211. This reduces the probability of deformation and cracking of the current collector 23 during welding, thereby improving the incoming material quality of the current collector 23 and further enhancing the connection quality between the current collector 23 and the first electrode tab 211 and the first electrode lead-out portion 22A.

[0285] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized in that, include: An electrode assembly includes an electrode sheet, the electrode sheet including a first tab protruding along a first direction; A housing assembly for accommodating the electrode assembly, the housing assembly including a first electrode lead-out portion; Current collection components, including The first connector is used to connect to the first electrode lead-out portion; as well as The second connector is used to connect to the first electrode tab; the base metal of the first connector and the second connector is different. Wherein, at least one of the first connector and the second connector is provided with a first groove, the first connector and the second connector are welded to form a first weld mark, the first weld mark is provided with at least one notch; in a projection plane perpendicular to the first direction, the orthographic projection of the first groove is at least partially located within the orthographic projection of the notch.

2. The battery cell according to claim 1, characterized in that, The first connector and the second connector are stacked along the first direction.

3. The battery cell according to claim 1, characterized in that, The first connector and the second connector are mated along a second direction, which is perpendicular to the thickness direction of the second connector.

4. The battery cell according to any one of claims 1-3, characterized in that, The first groove is located on the surface of the first connector; Wherein, along the first direction, the maximum groove depth of the first groove is less than the thickness of the first connector, or Along the first direction, at least a portion of the first groove extends through the first connector.

5. The battery cell according to any one of claims 1-3, characterized in that, The first groove is located on the surface of the second connector; Wherein, along the first direction, the maximum groove depth of the first groove is less than the thickness of the second connector; or Along the first direction, at least a portion of the first groove extends through the second connector.

6. The battery cell according to any one of claims 1-3, characterized in that, Both the first connector and the second connector are provided with the first groove; in the projection plane perpendicular to the first direction, the orthographic projection of the first groove provided on the first connector is completely offset from the orthographic projection of the first groove provided on the second connector.

7. The battery cell according to any one of claims 1-3, characterized in that, Both the first connector and the second connector are provided with the first groove; in a projection plane perpendicular to the first direction, the orthographic projection of the first groove provided on the first connector and the orthographic projection of the first groove provided on the second connector at least partially overlap.

8. The battery cell according to any one of claims 1-3, characterized in that, The first solder mark has a plurality of said notches, and the plurality of said notches break the first solder mark to form a multi-pass sub-solder mark; Wherein, in a projection plane perpendicular to the first direction, the orthographic projection of any of the first slots is at least partially disposed within the orthographic projection of the notch between two adjacent sub-soldering marks.

9. The battery cell according to any one of claims 1-3, characterized in that, In the projection plane perpendicular to the first direction, the sum of the central angles α formed by the geometric center of the orthographic projection of the first solder mark relative to the orthographic projection of the second connector satisfies: 210°≤α<360°.

10. The battery cell according to claim 1, characterized in that, The second connector includes: The first part, located in the central region of the second connector, is used for welding to the first electrode tab; and The second part surrounds the outer periphery of the first part and is used for welding connection with the first connector.

11. The battery cell according to claim 10, characterized in that, The first connector includes a hollowed-out area located in the central region. Furthermore, the first connector and the second connector are stacked along the first direction, and the first part is directly opposite the hollowed-out area; or The first connector and the second connector are disposed together along the second direction, and the second connector is located within the hollow area, with the second direction being perpendicular to the thickness direction of the second connector.

12. The battery cell according to claim 11, characterized in that, The first connector is a closed ring, and a plurality of the first grooves disposed on the first connector are spaced apart circumferentially along the geometric center of the first connector.

13. The battery cell according to any one of claims 10-12, characterized in that, Any of the first grooves disposed on the first connector extends radially along the geometric center of the first connector.

14. The battery cell according to any one of claims 10-12, characterized in that, The extension direction of the first groove disposed on the first connector intersects the extension direction of the first connector, and at least one of the first grooves is configured to completely disconnect the first connector.

15. The battery cell according to any one of claims 10-12, characterized in that, The first groove provided on the second connector is located in the second part of the second connector.

16. The battery cell according to claim 15, characterized in that, The plurality of first grooves disposed on the second connector extend radially along the geometric center of the second connector and are circumferentially spaced along the geometric center of the second connector.

17. The battery cell according to claim 16, characterized in that, The first part of the second connector also includes a second groove; Wherein, the second groove penetrates the second connector along the first direction, or the groove depth of the second groove along the first direction is less than the thickness of the second connector.

18. The battery cell according to claim 17, characterized in that, At least one of the second grooves extends in the same direction as the first groove disposed on the second connector, and both extend radially along the geometric center of the second connector.

19. The battery cell according to claim 17, characterized in that, At least one of the second grooves extends in a different direction than the first groove disposed on the second connector.

20. The battery cell according to claim 17, characterized in that, The second groove is multiple, and the multiple second grooves are arranged circumferentially along the geometric center of the second connector.

21. The battery cell according to claim 17, characterized in that, The second groove has multiple channels, with at least two channels having different extension lengths.

22. The battery cell according to claim 17, characterized in that, The second connector has a central through hole, and at least one end of the second groove is connected to the central through hole.

23. The battery cell according to claim 17, characterized in that, Both the second groove and the first groove disposed on the second connector extend radially along the geometric center of the second connector; Furthermore, along the extension direction of any of the second grooves or any of the first grooves, the ratio k of the effective length of the second connector from its geometric center to its outer edge without grooves to the total length of the second connector from its geometric center to its outer edge satisfies: 1 / 6 ≤ k ≤ 5 / 6.

24. The battery cell according to any one of claims 1-3, characterized in that, The first electrode lead-out portion is welded to the first connector to form a second solder mark; the orthographic projection of the second solder mark on the current collector is offset from the first solder mark.

25. The battery cell according to any one of claims 1-3, characterized in that, The base metal of the second connector is copper; the base metal of the first connector is steel or aluminum.

26. The battery cell according to any one of claims 1-3, characterized in that, The first connector includes a first metal layer and a first flux layer, wherein the first flux layer is disposed on at least one surface of the first metal layer; and / or The second connector includes a second metal layer and a second flux layer, wherein the second flux layer is disposed on at least one side of the surface of the second metal layer.

27. The battery cell according to any one of claims 1-3, characterized in that, The electrode assembly further includes a second electrode with a polarity different from that of the first electrode, and the first electrode and the second electrode are respectively located at both ends of the electrode assembly along the first direction. The housing assembly includes a housing and an end cap. The housing forms a receiving space for accommodating the electrode assembly. The housing includes an end wall at one end of the receiving space and an opening at the other end of the receiving space. The end cap is connected to the housing to cover the opening. The first electrode lead-out portion is either the end cap or the housing. The housing assembly further includes a second electrode lead-out portion, which is insulated through the end wall and electrically connected to the second electrode tab.

28. A battery, characterized in that, Includes the battery cell as described in any one of claims 1 to 27.

29. An electrical appliance, characterized in that, The electrical device includes the battery as described in claim 28, the battery being used to provide electrical energy.

30. An energy storage device, characterized in that, The energy storage device includes the battery as described in claim 29, the battery being used to store electrical energy and provide electrical energy.

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