Battery cell, battery and electrical apparatus

Abstract

The present application provides a battery cell, a battery and an electrical apparatus, and belongs to the technical field of batteries. The battery cell comprises an electrode assembly, a casing and a current collecting end cover. The electrode assembly comprises a first tab; the casing forms a containing cavity and an opening located at one end of the containing cavity, the containing cavity being used for containing the electrode assembly; the current collecting end cover is connected to the casing to seal the opening; the current collecting end cover comprises a tab connecting part and a casing connecting part which are connected to each other, the tab connecting part being connected to the first tab, and the casing connecting part being connected to the casing.

Description

Battery cells, batteries and electrical devices

[0001] Cross-references

[0002] This application refers to Chinese patent application No. 202311437733.7, filed on November 1, 2023, entitled “Battery Cell, Battery and Electrical Device,” which is incorporated herein by reference in its entirety. Technical Field

[0003] The present application relates to the field of battery technology, and in particular to a battery cell, a battery, and an electrical device. Background Art

[0004] Energy conservation and emission reduction are key to the sustainable development of the automotive industry. Electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of the sustainable development of the automotive industry. For electric vehicles, battery technology is a key factor in their development.

[0005] In existing battery structures, the tabs of a battery cell are usually first welded to a current collecting plate, which is then welded to an end cap, and finally the end cap is welded to the housing. This not only involves many welding steps, but also makes it easy for cold welds to occur between the current collecting plate and the end cap, thus affecting the performance and reliability of the battery cell.

[0006] Summary of the Invention

[0007] The present application aims to solve at least one of the technical problems existing in the background art. To this end, one object of the present application is to provide a battery cell, a battery and an electrical device to improve the reliability of the battery cell.

[0008] An embodiment of the first aspect of the present application provides a battery cell, comprising an electrode assembly, a housing, and a current collecting end cap. The electrode assembly includes a first tab; the housing defines a receiving cavity and an opening at one end of the receiving cavity, the receiving cavity being configured to receive the electrode assembly; the current collecting end cap is connected to the housing to seal the opening, and includes a tab connecting portion and a housing connecting portion connected to each other, the tab connecting portion being connected to the first tab, and the housing connecting portion being connected to the housing.

[0009] In the technical solution of the embodiment of the present application, a reliable connection between the tab connection part and the shell connection part can be completed before the tab connection part is connected to the first tab. This not only reduces the number of components during battery assembly and simplifies the welding process, but also reduces the risk of cold welding and improves the reliability of the battery cell.

[0010] In some embodiments, the tab connecting portion is welded to the first tab to form a weld region, and the projection of the weld region on the current collecting end cap is staggered relative to the housing connecting portion. This staggered projection of the weld region formed by the welding of the tab connecting portion to the first tab on the current collecting end cap facilitates connection of the current collecting end cap to the first tab and the housing, simplifies the manufacturing process of the battery cell, reduces the weight of the current collecting end cap, and improves the energy density of the battery cell.

[0011] In some embodiments, the elongation at break of the shell connection portion is less than that of the tab connection portion. By setting the elongation at break of the tab connection portion to be less than that of the shell connection portion, the different connection requirements of the tab connection portion and the shell connection portion as well as the overall structural strength requirements of the current collecting end cap can be better considered. At the same time, the tab connection portion will preferentially rupture when the internal pressure of the battery cell is high to facilitate pressure relief, thereby improving the reliability of the battery cell.

[0012] In some embodiments, the ratio S of the elongation at break of the shell connection portion to the elongation at break of the tab connection portion satisfies 1.1≤S≤2.2. By setting the ratio S of the elongation at break of the shell connection portion to the elongation at break of the tab connection portion to satisfy 1.1≤S≤2.2, the stability and service life of the current collecting end cap can be taken into account while meeting the structural strength and connection requirements of the current collecting end cap.

[0013] In some embodiments, the elongation at break S1 of the tab connection satisfies 0.2≤S1≤0.3, and the elongation at break S2 of the shell connection satisfies 0.35≤S2≤0.45. Reasonable selection of the elongation at break of the tab connection and the shell connection can ensure that the performance of the current collecting end cap meets both connection requirements and structural strength requirements.

[0014] In some embodiments, the tab connection portion includes a first body and a first connection portion connected to the first body and disposed along an outer edge of the first body; the shell connection portion includes a second connection portion and a first through-hole, the orthographic projection of the first body on the shell connection portion being located within the first through-hole, and the first connection portion and the second connection portion being welded together. By providing the first through-hole in the shell connection portion, the orthographic projection of the first body included in the tab connection portion being located within the first through-hole, and the first connection portion and the second connection portion being welded together, the integrated molding of the current collecting end cap can be better achieved, thereby reducing the risk of cold welding between the current collecting plate and the end cap caused by through-hole welding, simplifying the manufacturing process, and reducing manufacturing costs.

[0015] In some embodiments, the first connecting portion includes a first protrusion extending in a direction away from or toward the electrode assembly. Along a first direction, the first protrusion abuts the second connecting portion, where the first direction is from the center of the current collecting end cap toward the edge of the current collecting end cap. Providing the first protrusion on the first connecting portion for connection to the housing connecting portion allows for a simpler and more reliable connection between the tab connecting portion and the housing connecting portion.

[0016] In some embodiments, the second connection portion includes a second protrusion extending away from or toward the electrode assembly. Along a first direction, the second protrusion abuts the first connection portion, where the first direction is from the center of the current collecting end cap toward the edge of the current collecting end cap. Providing the second protrusion on the second connection portion simplifies and makes the connection between the tab connection portion and the housing connection portion more reliable.

[0017] In some embodiments, the first connecting portion includes a first protrusion extending away from the electrode assembly, and the second connecting portion includes a second protrusion extending toward the electrode assembly, with the first protrusion abutting the second protrusion along a first direction, where the first direction is from the center of the current collecting end cap to the edge of the current collecting end cap. Alternatively, the first connecting portion includes a second protrusion extending toward the electrode assembly, with the first protrusion abutting the second protrusion along the first direction, where the first direction is from the center of the current collecting end cap to the edge of the current collecting end cap. By providing the first protrusion on the first connecting portion and the second protrusion on the second connecting portion, the positioning between the first protrusion and the second protrusion can reduce the precision requirements for assembling the current collecting end cap by the operator, and also facilitate the welding process between the tab connection portion and the shell connection portion, thereby achieving a more reliable connection.

[0018] In some embodiments, the tab connection portion is flat, and the orthographic projection of the first connection portion on the shell connection portion at least partially overlaps the second connection portion. By configuring the tab connection portion as a flat plate and ensuring that the orthographic projection of the first connection portion on the shell connection portion at least partially overlaps the second connection portion, the thickness dimension of the current collecting end cap can be reduced while taking into account the connection and positioning of the tab connection portion and the shell connection portion, thereby facilitating an improvement in the energy density of the battery.

[0019] In some embodiments, the side of the tab connection facing the electrode assembly is flush with the side of the housing connection facing the electrode assembly. By making the side of the tab connection facing the electrode assembly flush with the side of the housing connection facing the electrode assembly, the height of the current collecting end cover can be reduced while maintaining the strength of the current collecting end cover, thereby increasing the capacity of the housing cavity and reducing the height of the battery cell.

[0020] In some embodiments, the base metals of the tab connection portion and the shell connection portion are different. By setting the base metals of the tab connection portion and the shell connection portion to be different, the different connection requirements of the tab connection portion and the shell connection portion as well as the overall strength requirements of the current collecting end cap can be better considered, thereby improving the performance and reliability of the battery cell.

[0021] In some embodiments, the base metal of the tab connection portion is copper, and the base metal of the shell connection portion is iron or aluminum. By using copper as the base metal of the tab connection portion and iron or aluminum as the base metal of the shell connection portion, the current-collecting end cap's current carrying capacity and structural strength can be improved, thereby enhancing the reliability of the battery cell.

[0022] In some embodiments, the base metal of the tab connection portion and the shell connection portion is the same. Setting the base metal of the tab connection portion and the shell connection portion to be the same can simplify the preparation of the current collecting end cap and reduce the risk of unreliable connection between the tab connection portion and the shell connection portion.

[0023] In some embodiments, the base metal of the tab connection portion and the shell connection portion is copper. Selecting copper as the base metal of the tab connection portion and the shell connection portion can improve the current flow capacity and corrosion resistance of the current collecting end cap and improve the reliability of the battery cell.

[0024] In some embodiments, the maximum thickness of the tab connection is d1, the minimum thickness of the shell connection is d2, and d1 ≤ d2. The thicker the component, the greater the bending strength of the component. The maximum thickness d1 of the tab connection must be less than or equal to the minimum thickness d2 of the shell connection. This is equivalent to increasing the thickness of the shell connection to enhance the overall strength and deformation resistance of the current collecting end cap. Furthermore, a smaller thickness of the tab connection helps reduce internal resistance and the weight of the current collecting end cap, thereby improving the performance of the battery cell.

[0025] In some embodiments, the maximum thickness of the tab connection portion is d1, the minimum thickness of the shell connection portion is d2, and the following relationship is satisfied: 0.5 ≤ d1 / d2 ≤ 1. By controlling the ratio of the thickness of the tab connection portion d1 to the thickness of the shell connection portion d2 within an appropriate range, the structural strength of the current collecting end cap and the energy density of the battery cell can be balanced, thereby improving the performance of the battery cell.

[0026] In some embodiments, a ratio a of the projected area of ​​the tab connection portion on the first plane to the projected area of ​​the current collecting end cap on the first plane satisfies the following condition: 0.1 ≤ a ≤ 0.95, where the first plane is a plane perpendicular to the thickness direction of the current collecting end cap. Limiting the ratio a of the projected area of ​​the tab connection portion on the first plane to the projected area of ​​the current collecting end cap on the first plane within an appropriate range can better balance the connection reliability and current flow capacity of the current collecting end cap and the first tab, as well as the overall structural strength, thereby improving the reliability of the current collecting end cap.

[0027] In some embodiments, a ratio a of the projected area of ​​the tab connection portion on the first plane to the projected area of ​​the current collecting end cap on the first plane satisfies the following: 0.4 ≤ a ≤ 0.6. By setting the ratio a between the area of ​​the tab connection portion and the area of ​​the current collecting end cap to be between 0.4 and 0.6, the current collecting end cap can achieve more uniformity in terms of current flow capacity, connection reliability, and structural strength.

[0028] In some embodiments, the current collecting end cap further includes a structural reinforcement portion located at one end of the shell connection portion near the shell. Along the thickness direction of the current collecting end cap, the maximum dimension of the structural reinforcement portion is greater than the maximum thickness of the shell connection portion. Adding the structural reinforcement portion to the shell connection portion increases the overall strength of the current collecting end cap and improves its deformation resistance. This not only facilitates installation and welding positioning during connection, but also helps improve the structural reliability of the battery cell.

[0029] In some embodiments, the structural reinforcement portion includes at least one third protrusion, which protrudes relative to the housing connection portion in a direction away from the electrode assembly or in a direction toward the electrode assembly. Providing the structural reinforcement portion with a third protrusion simplifies its structure, facilitates manufacturing, and reduces unnecessary weight while providing strength support.

[0030] In some embodiments, the projection of the third protrusion on a first plane is annular, wherein the first plane is a plane perpendicular to the thickness direction of the current collecting end cover. The third protrusions can be continuously arranged along the outer circumference of the housing connecting portion to form an annular reinforcement portion, which can further increase the structural strength of the current collecting end cover.

[0031] In some embodiments, there are multiple third protrusions, spaced apart along a first direction, where the first direction is from the center of the current collecting end cap toward the edge of the current collecting end cap. By providing multiple third protrusions along the direction from the center of the current collecting end cap toward the edge of the current collecting end cap, compared to increasing the overall thickness, it is possible to more effectively balance strength requirements and energy density requirements, thereby improving the overall performance of the battery cell.

[0032] In some embodiments, the ratio of the projected area of ​​the tab connection portion on the first plane to the projected area of ​​the current collecting end cap on the first plane is a, and the minimum thickness of the tab connection portion along the thickness direction of the current collecting end cap is d0, where 0.05≤d0 / a≤40, and the first plane is a plane perpendicular to the thickness direction of the current collecting end cap. By setting the ratio of the projected area of ​​the tab connection portion on the first plane to the projected area of ​​the current collecting end cap on the first plane a to the minimum thickness of the tab connection portion along the thickness direction of the current collecting end cap d0 between 0.05 and 40, the area where the tab connection portion is located can be made to have suitable valve opening strength as an explosion-proof valve, thereby achieving more stable and reliable valve opening pressure relief, thereby improving the reliability of the battery cell.

[0033] In some embodiments, the value of d0 / a satisfies the following: 0.8≤d0 / a≤1.6. By setting the ratio (a) of the projected area of ​​the tab connection portion on the first plane to the projected area of ​​the current collecting end cap on the first plane to the minimum thickness d0 of the tab connection portion along the thickness direction of the current collecting end cap between 0.8 and 1.6, the opening strength of the explosion-proof valve of the battery cell can be adjusted to a more appropriate range, thereby improving the reliability of the battery cell.

[0034] In some embodiments, the housing includes an end wall distal from the opening, the end wall being provided with a second through-hole, the electrode assembly further including a second tab proximate the end wall, the second tab having a different polarity than the first tab, and the battery cell further including an electrode terminal, the electrode terminal being disposed through the through-hole and electrically connected to the second tab. With the electrode terminal disposed through the second through-hole and electrically connected to the second tab, the current collecting end cap is electrically connected to the first tab, and the current collecting end cap achieves an integrated design of the current collecting disc and the end cap, thereby achieving a reliable electrical connection between the current collecting disc and the end cap before battery assembly, reducing the risk of cold solder joints during battery cell assembly, thereby improving the reliability of the battery cell.

[0035] An embodiment of the second aspect of the present application provides a method for manufacturing a battery cell, which includes: providing an electrode assembly, a shell and a current collecting end cover respectively, the electrode assembly including a first pole ear, the shell forming a accommodating cavity and an opening at one end of the accommodating cavity, the current collecting end cover including a connected pole ear connection portion and a shell connection portion, placing the electrode assembly into the accommodating cavity of the shell, welding the pole ear connection portion of the current collecting end cover to the first pole ear of the electrode assembly, and welding the shell connection portion of the current collecting end cover to the shell.

[0036] In the technical solution of the embodiment of the present application, in the assembly process of the battery cell, the collecting end cover is a separate incoming part, and a reliable connection between the pole tab connection part and the shell connection part is achieved before being welded with the first pole tab and the shell. This can simplify the welding process during the assembly of the battery cell, reduce the risk of cold welding, and improve the reliability of the battery cell.

[0037] In some embodiments, welding the tab connection portion of the current collecting end cap to the first tab of the electrode assembly includes: arranging the current collecting end cap at the opening of the housing so that the tab connection portion abuts the first tab; and emitting a laser from a side of the current collecting end cap away from the electrode assembly and penetrating the tab connection portion to weld the tab connection portion to the first tab. Arranging the current collecting end cap at the opening of the housing so that the tab connection portion abuts the first tab, and emitting a laser from a side of the current collecting end cap away from the electrode assembly and penetrating the tab connection portion to weld the tab connection portion to the first tab further simplifies the welding process of the battery cells.

[0038] An embodiment of the third aspect of the present application provides a battery, which includes the battery cell in the above embodiment.

[0039] An embodiment of the fourth aspect of the present application provides an electrical device, which includes the battery in the above embodiment, and the battery is used to provide electrical energy.

[0040] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in the present application and should not be regarded as limiting the scope of the present application. In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on the drawings without paying creative work.

[0042] FIG1 is a schematic structural diagram of a vehicle according to some embodiments of the present application;

[0043] FIG2 is a schematic diagram of the exploded structure of a battery according to some embodiments of the present application;

[0044] FIG3 is a schematic diagram of the exploded structure of a battery cell according to some embodiments of the present application;

[0045] FIG4 is a schematic structural diagram of a battery cell according to some embodiments of the present application;

[0046] FIG5 is a first structural diagram of a current collecting end cover according to some embodiments of the present application;

[0047] FIG6 is a second structural diagram of a current collecting end cover according to some embodiments of the present application;

[0048] FIG7 is a third structural diagram of a current collecting end cover according to some embodiments of the present application;

[0049] FIG8 is a fourth structural diagram of a current collecting end cover according to some embodiments of the present application;

[0050] FIG9 is a fifth structural diagram of a current collecting end cover according to some embodiments of the present application;

[0051] FIG10 is a sixth structural diagram of a current collecting end cover according to some embodiments of the present application;

[0052] FIG11 is a seventh structural diagram of a current collecting end cover according to some embodiments of the present application;

[0053] FIG12 is a structural schematic diagram 8 of a current collecting end cover according to some embodiments of the present application;

[0054] FIG13 is a ninth structural diagram of a current collecting end cover according to some embodiments of the present application;

[0055] FIG14 is a top view of a current collecting end cover according to some embodiments of the present application;

[0056] FIG15 is a top view of a current collecting end cover according to some other embodiments of the present application;

[0057] FIG16 is a schematic structural diagram of another battery cell according to some embodiments of the present application;

[0058] FIG. 17 is a flow chart of a method for manufacturing a battery cell according to some embodiments of the present application.

[0059] Description of reference numerals:

[0060] 1000. Vehicle;

[0061] 100, battery; 200, controller; 300, motor;

[0062] 10. Box body; 11. First part; 12. Second part;

[0063] 20. Battery cell; 21. Current collecting end cap; 211. Electrode terminal; 22. Shell; 23. Electrode assembly; 24. Tab; 25. First plane; 241. First tab; 242. Second tab; 212. Tab connection; 213. Shell connection; 2121. First body; 2122. First connection; 2131. Second connection; 2133. Structural reinforcement; 2134. Third protrusion. DETAILED DESCRIPTION

[0064] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0065] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0066] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0067] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0068] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0069] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0070] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0071] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0072] Currently, market developments indicate that power batteries are becoming increasingly widely used. They are not only used in energy storage systems such as hydropower, thermal, wind, and solar power plants, but are also widely used in electric vehicles like electric bicycles, electric motorcycles, and electric vehicles, as well as in military equipment and aerospace. As power battery applications continue to expand, market demand is also growing.

[0073] Cylindrical batteries are a common type of battery. In related technologies, a cylindrical battery cell consists of a housing, an electrode assembly, and an end cap. The negative electrode tab of a cylindrical battery cell is typically first connected to a current collector plate, which is then connected to the end cap, and then to the housing through the end cap, ultimately achieving charging of the housing.

[0074] In the related art, the end cap of the cylindrical battery cell is located on the outside of the negative electrode current collecting plate, and electrical connection is achieved by penetration welding from the end cap side. However, due to the inherent poor reliability of penetration welding and the flatness problem of the end cap material, the current penetration welding is prone to cause cold welding problems between the current collecting plate and the end cap, resulting in poor electrical connection of the battery cell, affecting the performance and reliability of the battery cell. At the same time, the method of penetration welding the end cap and the current collecting plate from the end cap side may damage the coating on the surface of the end cap, reducing the reliability of the end cap.

[0075] Based on the above considerations, in order to solve the problem of cold welding between the current collecting plate and the end cover, the present application proposes a battery cell, including a current collecting end cover connected to the pole lug and the shell, by connecting the pole lug connecting part on the current collecting end cover to the first pole lug, and connecting the shell connection part to the shell, that is, the current collecting end cover realizes an integrated design of the current collecting plate and the end cover, and can achieve a reliable connection between the pole lug connecting part and the shell connection part before the step of connecting the pole lug connecting part to the first pole lug, which not only reduces the number of components during battery assembly and simplifies the welding process, but also reduces the risk of cold welding and improves the reliability of the battery cell.

[0076] The battery cells disclosed in the embodiments of this application can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft. A power supply system comprising the battery cells and batteries disclosed in this application can be used to reduce the problem of poor electrical connections in the battery cells and improve the reliability of the battery cells.

[0077] The present invention provides an electric device that uses a battery as a power source. The electric device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery-powered vehicle, an electric car, a ship, a spacecraft, etc. The electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc. The spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0078] For the convenience of description, the following embodiments are described by taking a vehicle 1000 as an example of an electrical device according to an embodiment of the present application.

[0079] Please refer to Figure 1, which is a schematic structural diagram of a vehicle 1000 provided in some embodiments of the present application. The vehicle 1000 can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000, and the battery 100 can be provided at the bottom, head or tail of the vehicle 1000. The battery 100 can be used to power the vehicle 1000. For example, the battery 100 can serve as an 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 power the motor 300, for example, for starting, navigating and driving the vehicle 1000.

[0080] In some embodiments of the present application, the battery 100 can serve not only as an operating power source for the vehicle 1000, but also as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0081] Please refer to Figure 2, which is a schematic diagram of the exploded structure of a battery 100 provided in some embodiments of the present application. The battery 100 includes a housing 10 and battery cells 20, with the battery cells 20 housed within the housing 10. The housing 10 provides a storage space for the battery cells 20 and can have various structures. In some embodiments, the housing 10 can include a first portion 11 and a second portion 12, which overlap each other and together define a storage space for the battery cells 20. The second portion 12 can be a hollow structure with one end open. The first portion 11 can be a plate-like structure, with the first portion 11 overlapping the open side of the second portion 12, so that the first portion 11 and the second portion 12 together define a storage space. Alternatively, the first portion 11 and the second portion 12 can each be a hollow structure with one end open, with the open side of the first portion 11 overlapping 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 or a rectangular parallelepiped.

[0082] In the battery 100, there may be multiple battery cells 20, and the multiple battery cells 20 may be connected in series, in parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections among the multiple battery cells 20. The multiple battery cells 20 may be directly connected in series, in parallel, or in a hybrid connection, and then the entire battery cell 20 may be housed within the housing 10. Alternatively, the battery 100 may be constructed by first connecting multiple battery cells 20 in series, in parallel, or in a hybrid connection to form a battery module, which is then connected in series, in parallel, or in a hybrid connection to form a complete battery module, and then housed within the housing 10. The battery 100 may also include other structures, such as a busbar assembly for electrically connecting the multiple battery cells 20.

[0083] Each battery cell 20 may be a secondary battery or a primary battery, and may also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 20 may be cylindrical, flat, rectangular, or in other shapes.

[0084] According to some embodiments of the present application, referring to Figures 3 and 4, Figure 3 is a schematic diagram of the decomposed structure of a battery cell 20 provided in some embodiments of the present application, and Figure 4 is a schematic diagram of the structure of a battery cell in some embodiments of the present application. The present application provides a battery cell 20, which includes an electrode assembly 23, a shell 22, and a current collecting end cover 21. The electrode assembly 23 includes a first pole tab 241; the shell 22 is formed with a receiving cavity and an opening at one end of the receiving cavity, and the receiving cavity is used to accommodate the electrode assembly 23; the current collecting end cover 21 is connected to the shell 22 to close the opening, and the current collecting end cover 21 includes a connected pole tab connection portion 212 and a shell connection portion 213, wherein the pole tab connection portion 212 is connected to the first pole tab 241, and the shell connection portion 213 is connected to the shell 22.

[0085] In the embodiment of the present application, the battery cell 20 may include a lithium-ion secondary battery, a lithium-ion primary battery, a lithium-sulfur battery, a sodium-lithium-ion battery, a sodium-ion battery, or a magnesium-ion battery, etc., and the embodiment of the present application is not limited to this. The battery cell 20 may be cylindrical, flat, rectangular, or other shapes, and the embodiment of the present application is not limited to this.

[0086] The electrode assembly 23 is a component in the battery cell 20 where electrochemical reactions occur. The housing formed by the shell 22 may include one or more electrode assemblies 23. The electrode assembly 23 is mainly formed by winding or stacking positive and negative electrode sheets, and a separator is usually provided between the positive and negative electrode sheets. The parts of the positive and negative electrode sheets with active materials constitute the main body of the electrode assembly 23, and the parts of the positive and negative electrode sheets without active materials each constitute a tab 24. The positive and negative tabs may be located together at one end of the main body or respectively at both ends of the main body. During the charge and discharge process of the battery cell 20, the positive active material and the negative active material react with the electrolyte, and the tab 24 connects to the electrode terminal 211 to form a current loop. In the embodiment of the present application, the first tab 241 may be a negative tab.

[0087] The current collecting end cap 21 is a component that covers the opening of the housing 22 to isolate the receiving cavity of the battery cell 20 from the external environment. Without limitation, the shape of the current collecting end cap 21 can be adapted to the shape of the housing 22 to match the housing 22.

[0088] In the embodiment of the present application, the current collecting end cover 21 includes a connected pole tab connection portion 212 and a shell connection portion 213. The pole tab connection portion 212 is connected to the first pole tab 241 and acts as a current collecting plate. The shell connection portion 213 is located on the side of the pole tab connection portion 212 close to the shell 22 and is connected to the shell 22, so that the current collecting end cover 21 acts as an end cover to close the opening of the shell 22. In other words, the current collecting end cover 21 combines the functions of the current collecting plate and the end cover, and the current collecting end cover 21 is an integrated structure of the current collecting plate and the end cover. The pole tab connection portion 212 and the shell connection portion 213 can be integrally formed or manufactured separately and then fixed together. The current collecting end cover 21 can connect the pole tab connection portion 212 to the first pole tab 241 and the shell connection portion 213 to the shell 22 respectively. The connection method can also be welding, such as laser welding or friction welding.

[0089] The housing 22 is a component that cooperates with the current collecting end cap 21 to form a housing cavity for the battery cell 20. This cavity can be used to accommodate the electrode assembly 23, electrolyte, and other components. The housing 22 and the current collecting end cap 21 can be separate components. An opening can be provided in the housing 22, and the current collecting end cap 21 can be used to close the opening to form a housing cavity for the battery cell 20. Alternatively, the current collecting end cap 21 and the housing 22 can be integrated. Specifically, the current collecting end cap 21 and the housing 22 can form a common connection surface before other components are inserted into the housing. When the interior of the housing 22 needs to be enclosed, the current collecting end cap 21 can be used to seal the housing 22. The housing 22 can be of various shapes and sizes, such as a rectangular parallelepiped, a cylinder, or a hexagonal prism. Specifically, the shape of the housing 22 can be determined based on the specific shape and size of the electrode assembly 23. The housing 22 can be made of a variety of materials, such as copper, iron, aluminum, stainless steel, and aluminum alloys, but this is not limited in this embodiment of the present application.

[0090] In the embodiment of the present application, a reliable connection between the pole tab connection portion 212 and the shell connection portion 213 can be completed before the pole tab connection portion 212 is connected to the first pole tab 241. This not only reduces the number of components during assembly of the battery 100 and simplifies the welding process, but also reduces the risk of cold welding and improves the reliability of the battery cell 20.

[0091] According to some embodiments of the present application, the tab connection portion 212 is welded to the first tab 241 to form a welding region Q. The projection of the welding region Q on the current collecting end cover 21 is staggered with the shell connection portion 213 .

[0092] As shown in FIG4 , the tab connection portion 212 can be located in the central region of the current collecting end cap 21, and the shell connection portion 213 can be located in a peripheral region surrounding the tab connection portion 212. In some examples, the tab connection portion 212 and the shell connection portion 213 may partially overlap along the thickness direction of the current collecting end cap 21, or they may be positioned adjacent to each other without overlapping, but the overlapping region does not extend to the region of the tab connection portion 212 used for welding to the first tab 241. This allows the shell connection portion 213 to expose the region of the tab connection portion 212 used for welding to the first tab 241, thereby facilitating welding of the tab connection portion 212 and the first tab 241 to form the weld region Q during assembly of the battery cell 20. In some examples, the weld region Q is formed by laser welding the tab connection portion 212 and the first tab 241. For example, a laser is emitted from the outer side of the current collecting end cap 21 (away from the electrode assembly) to sequentially melt the tab connection portion 212 and then (at least a portion of) the first tab 241 to form the weld region Q.

[0093] In the embodiment of the present application, the projection of the welding area Q formed by welding the pole tab connection portion 212 and the first pole tab 241 on the current collecting end cover 21 is staggered with the shell connection portion 213, which is more conducive to the connection of the current collecting end cover 21 with the first pole tab 241 and the shell 22 respectively, simplifies the manufacturing process of the battery cell 20, and can reduce the weight of the current collecting end cover 21, which is conducive to improving the energy density of the battery cell 20.

[0094] According to some embodiments of the present application, the fracture elongation of the shell connection portion 213 is smaller than the fracture elongation of the tab connection portion 212 .

[0095] In the embodiment of the present application, the elongation at fracture is the ratio of the length increment of the material before it is stretched to fracture to the original length. The specific testing method for the elongation at fracture is as follows: take a tensile specimen with an original length of L0, and stretch the tensile specimen on a tensile testing machine until it breaks. The length of the tensile specimen before it is stretched to fracture is Lh, then the elongation at fracture of the tensile specimen is Δh = (Lh-L0) / L0×100%. The specific conditions and requirements of the tensile test can be implemented in accordance with the relevant standards, for example, in accordance with the relevant provisions and requirements in the Chinese national standard GB / T 228.1-2021 "Tensile Test of Metal Materials Part 1: Room Temperature Test Method".

[0096] Elongation at break is closely related to factors such as the material's composition, structure, and processing. Generally speaking, the higher the elongation at break, the better the material's ductility, allowing it to undergo plastic deformation under external forces, thereby mitigating stress concentration and improving the material's tensile strength and impact resistance. Furthermore, materials with high elongation at break exhibit superior toughness, absorbing energy when subjected to external forces such as shock or vibration, thereby reducing the likelihood of accidents. Furthermore, materials with high elongation at break can also extend the product's service life and reliability.

[0097] In the embodiment of the present application, the current collecting end cap 21 needs to be connected to the first pole tab 241 and the shell 22 respectively. When selecting materials and processing, it is necessary to consider the welding process requirements and electrical conductivity requirements when welding to the first pole tab 241, and at the same time, the structural strength requirements of the battery end cap must also be considered. By rationally selecting the material type and / or processing method based on the performance requirements of the pole tab connection portion 212 and the shell connection portion 213, the elongation at break of the shell connection portion 213 can be made greater than the elongation at break of the pole tab connection portion 212. In this way, the pole tab connection portion 212 can be designed with more consideration for the overcurrent problem with the first pole tab 241, while the shell connection portion 213 can provide support for the overall structural strength of the current collecting end cap 21. In some embodiments, the tab connection portion 212 and the shell connection portion 213 have different elongations at break, so that the tab connection portion 212 located on the current collecting end cover 21 will form a structurally weakened area relative to the shell connection portion 213. Once thermal runaway occurs inside the battery cell 20, the welded area between the tab connection portion 212 and the first tab 241 can serve as a weak area of ​​the current collecting end cover 21 and rupture, thereby improving the reliability of pressure relief to a certain extent.

[0098] In the embodiment of the present application, by setting the fracture elongation of the pole tab connection part 212 to be smaller than the fracture elongation of the shell connection part 213, the different connection requirements of the pole tab connection part 212 and the shell connection part 213 and the overall structural strength requirements of the collecting end cover 21 can be better taken into account. At the same time, the pole tab connection part 212 will rupture first to facilitate pressure relief when the internal pressure of the battery cell 20 is relatively high, thereby improving the reliability of the battery cell 20.

[0099] According to some embodiments of the present application, a ratio S of the elongation at break of the shell connection portion 213 to the elongation at break of the tab connection portion 212 satisfies 1.1≤S≤2.2.

[0100] In the embodiment of the present application, the shell connection portion 213 and the tab connection portion 212 are both part of the current collecting end cap 21. Therefore, when selecting materials and formulating processing techniques, in addition to considering the performance requirements of the shell connection portion 213 and the tab connection portion 212, the stability and reliability of the overall performance of the current collecting end cap 21 formed by the two must also be considered. Therefore, the difference between the elongation at break of the shell connection portion 213 and the elongation at break of the tab connection portion 212 should not be too large, otherwise the current collecting end cap 21 will have insufficient overall performance reliability due to the large local performance difference, thereby affecting the service life of the current collecting end cap 21. Optionally, the ratio S of the elongation at break of the shell connection portion 213 to the elongation at break of the tab connection portion 212 can be 1.1, 1.3, 1.5, 1.7, 1.9, 2.0, or 2.2, etc.

[0101] In the embodiment of the present application, by setting the ratio S of the fracture elongation of the shell connection part 213 to the fracture elongation of the tab connection part 212 to satisfy 1.1≤S≤2.2, the stability of the performance and service life of the current collecting end cover 21 can be taken into account while meeting the structural strength and connection requirements of the current collecting end cover 21.

[0102] According to some embodiments of the present application, the elongation at break S1 of the tab connection portion 212 satisfies 0.2≤S1≤0.3, and the elongation at break S2 of the shell connection portion 213 satisfies 0.35≤S2≤0.45.

[0103] In the embodiment of the present application, when the elongation at break of the material is larger, its ductility is better. Conversely, when the elongation at break is smaller, the material is more likely to break during stress. Reasonable selection of the elongation at break of the tab connection portion 212 and the shell connection portion 213 can make the two better meet the connection requirements and make the tab connection portion 212 the first to break when the internal pressure of the battery cell 20 is too large. Optionally, the elongation at break S1 of the tab connection portion 212 can be 0.2, 0.24, 0.26, 0.28, 0.3, etc., and the elongation at break S2 of the shell connection portion 213 can be 0.35, 0.38, 0.4, 0.42, 0.45, etc. In some examples, the tab connection portion 212 can be made of copper with a elongation at break of 0.24, such as CuT2 material, and the shell connection portion 213 can be made of nickel-plated steel with a elongation at break of 0.4.

[0104] In the embodiment of the present application, reasonable selection of the elongation at break of the tab connection portion 212 and the elongation at break of the shell connection portion 213 can enable the performance of the current collecting end cover 21 to take into account both connection requirements and structural strength requirements.

[0105] According to some embodiments of the present application, Figure 5 is a structural schematic diagram of the collecting end cover of some embodiments of the present application. As shown in Figure 5, the pole ear connection portion 212 includes a first main body 2121 and a first connection portion 2122 connected to the first main body 2121 and arranged along the outer edge of the first main body 2121; the shell connection portion 213 includes a second connection portion 2131 and a first through hole, the orthographic projection of the first main body 2121 on the shell connection portion 213 is located in the first through hole, and the first connection portion 2122 is welded to the second connection portion 2131.

[0106] In the embodiment of the present application, the tab connection portion 212 includes a first body 2121, which is used to connect to the first tab 241. A first connection portion 2122 provided on the outer edge of the first body 2121 is used to connect to the housing connection portion 213. The first body 2121 and the first connection portion 2122 can be a unitary structure. The shape of the first connection portion 2122 can be any shape that can be connected to the second connection portion 2131. The shape of the first connection portion 2122 can be the same as the shape of the second connection portion 2131. For example, the shape of the first connection portion 2122 is a protrusion or a flat plate.

[0107] In the embodiment of the present application, the first through hole is defined by the second connecting portion 2131, the first through hole is formed in the central area of ​​the shell connecting portion 213, and the second connecting portion 2131 is arranged along the edge of the first through hole. In some examples, the first through hole is defined by the second connecting portion 2131. The shape of the first through hole can be any polygon, such as a circle, a square, a rectangle, a triangle, a diamond, a hexagon, etc. The shape of the first body 2121 can be adapted to the shape of the first through hole, and the orthographic projection of the first body 2121 on the shell connecting portion 213 is located in the first through hole, that is, the projected area of ​​the first body 2121 is smaller than the area of ​​the first through hole, so as to facilitate the connection between the first body 2121 of the collecting end cover 21 and the first pole ear 241.

[0108] In the embodiment of the present application, a first through hole is provided on the shell connection portion 213, the positive projection of the first main body 2121 included in the pole tab connection portion 212 on the shell connection portion 213 is located within the first through hole, and the first connection portion 2122 is welded to the second connection portion 2131, so that the one-piece forming of the collecting end cover 21 can be better achieved, thereby reducing the risk of cold welding between the collecting plate and the end cover caused by the use of through-hole welding, simplifying the manufacturing process and reducing the manufacturing cost.

[0109] According to some embodiments of the present application, the first connecting portion 2122 includes a first protrusion extending in a direction away from or close to the electrode assembly 23, and along the first direction X, the first protrusion abuts against the second connecting portion 2131, and the first direction X is the direction from the center of the current collecting end cover 21 to the edge of the current collecting end cover 21.

[0110] In the embodiment of the present application, the first protrusion can be distributed on the outer edge of the first body 2121, and the extension direction of the first protrusion is from the first body 2121 to the direction away from or close to the electrode assembly 23. By abutting the first protrusion with the second connection portion 2131, the first protrusion can be used to guide the tab connection portion 212 to complete rapid positioning when connecting with the shell connection portion 213, which is beneficial to the welding connection between the first connection portion 2122 and the second connection portion 2131 in the subsequent process, reducing the accuracy requirements of the operator during assembly, and making the connection between the tab connection portion 212 and the shell connection portion 213 simpler and more convenient. In addition, by providing the first protrusion, the welding position of the tab connection portion 212 and the shell connection portion 213 and the connection position with the first tab 241 can be staggered. At the same time, the first protrusion and the shell connection portion 213 can also be connected by other welding methods other than penetration welding, such as butt welding, thereby providing more reliable connection methods.

[0111] For example, FIG6 is a second structural schematic diagram of the current collecting end cap 21 according to some embodiments of the present application. As shown in FIG6 , the first connecting portion 2122 includes a first protrusion extending in a direction away from the electrode assembly 23. Along the first direction X, the first protrusion abuts against the second connecting portion 2131. In this way, the tab connecting portion 212 can be better positioned close to the first tab 241 for welding thereto, achieving a more reliable electrical connection.

[0112] In the embodiment of the present application, by providing a first protrusion on the first connection portion 2122 for connection with the shell connection portion 213 , a simpler and more reliable connection between the tab connection portion 212 and the shell connection portion 213 can be achieved.

[0113] According to some embodiments of the present application, the second connection portion 2131 includes a second protrusion extending in a direction away from or close to the electrode assembly 23, and along the first direction X, the second protrusion abuts against the first connection portion 2122, and the first direction X is the direction from the center of the current collecting end cover 21 to the edge of the current collecting end cover 21.

[0114] In the embodiment of the present application, the second protrusion can be distributed on the edge of the shell connection portion 213 close to the tab connection portion 212, and the extension direction of the second protrusion is from the shell connection portion 213 toward or away from the electrode assembly 23, so as to facilitate the abutment of the second protrusion with the first connection portion 2122. In this way, the second protrusion can be used to guide the tab connection portion 212 to complete rapid positioning when connected to the shell connection portion 213, which is beneficial to the welding connection between the first connection portion 2122 and the second connection portion 2131 in the subsequent process, reducing the accuracy requirements of the operator during assembly, making the connection between the tab connection portion 212 and the shell connection portion 213 simpler and more convenient. The second protrusion and the tab connection portion 212 can also be connected by other welding methods other than penetration welding, such as butt welding, thereby providing more reliable connection methods.

[0115] Figure 7 is a third structural schematic diagram of the current collecting end cover 21 of some embodiments of the present application. As shown in Figure 7, the second connecting portion 2131 includes a second protrusion extending in a direction close to the electrode assembly 23. Along the first direction X, the second protrusion abuts against the first connecting portion 2122.

[0116] In the embodiment of the present application, by providing a second protrusion on the second connecting portion 2131 , the connection between the tab connecting portion 212 and the shell connecting portion 213 is made simpler and more reliable.

[0117] According to some embodiments of the present application, the first connecting portion 2122 includes a first protrusion extending in a direction away from the electrode assembly 23, and the second connecting portion 2131 includes a second protrusion extending in a direction close to the electrode assembly 23, and along the first direction X, the first protrusion abuts the second protrusion, and the first direction X is the direction from the center of the current collecting end cover 21 to the edge of the current collecting end cover 21; or, the first connecting portion 2122 includes a second protrusion extending in a direction close to the electrode assembly 23, and along the first direction X, the first protrusion abuts the second protrusion, and the first direction X is the direction from the center of the current collecting end cover 21 to the edge of the current collecting end cover 21.

[0118] In the embodiment of the present application, the first protrusion is distributed on the outer edge of the first body 2121, and the first protrusion protrudes relative to the first body 2121 in the direction away from the electrode assembly 23; the second protrusion is distributed on the edge of the shell connection part 213 close to the tab connection part 212, and the second protrusion protrudes in the direction close to the electrode assembly 23. The first protrusion and the second protrusion are abutted to complete the positioning of the tab connection part 212 and the shell connection part 213 before welding, which is beneficial to the welding connection of the first connection part 2122 and the second connection part 2131 in the subsequent process. The first protrusion and the second protrusion can be connected by penetration welding, or by other welding methods other than penetration welding, such as butt welding. The protrusion height of the first protrusion and the protrusion height of the second protrusion can be the same or different.

[0119] For example, Figure 8 is a fourth structural schematic diagram of the current collecting end cover 21 of some embodiments of the present application. As shown in Figure 8, the first connecting portion 2122 includes a first protrusion extending in a direction away from the electrode assembly 23, and the second connecting portion 2131 includes a second protrusion extending in a direction close to the electrode assembly 23. Along the first direction X, the first protrusion abuts the second protrusion.

[0120] In the embodiment of the present application, by providing a first protrusion on the first connecting portion 2122 and a second protrusion on the second connecting portion 2131, the positioning between the first protrusion and the second protrusion can reduce the accuracy requirements of the operator when assembling the collecting end cover 21, and is also beneficial to the welding process between the pole ear connecting portion 212 and the shell connecting portion 213, thereby achieving a more reliable connection.

[0121] According to some embodiments of the present application, Figure 9 is a structural schematic diagram 5 of the current collecting end cover 21 of some embodiments of the present application. As shown in Figure 9, the pole ear connection portion 212 is flat, and the orthographic projection of the first connection portion 2122 on the shell connection portion 213 at least partially overlaps with the second connection portion 2131.

[0122] In an embodiment of the present application, the tab connection portion 212 is flat, the first connection portion 2122 is arranged around the periphery of the first main body 2121, and the projection area of ​​the tab connection portion 212 along its thickness direction is larger than the area of ​​the first through hole on the shell connection portion 213, so that the positive projection of the first connection portion 2122 on the shell connection portion 213 at least partially overlaps with the second connection portion 2131, that is, the first connection portion 2122 at least partially overlaps one side surface of the second connection portion 2131, so that the first connection portion 2122 and the second connection portion 2131 can be connected by welding.

[0123] In the embodiment of the present application, by setting the pole tab connection portion 212 as a flat plate and making the positive projection of the first connection portion 2122 on the shell connection portion 213 at least partially overlap with the second connection portion 2131, the size of the collecting end cover 21 along the thickness direction can be reduced while taking into account the connection and positioning of the pole tab connection portion 212 and the shell connection portion 213, which is beneficial to improving the energy density of the battery.

[0124] According to some embodiments of the present application, Figure 10 is a structural schematic diagram six of the current collecting end cover 21 of some embodiments of the present application. As shown in Figure 10, the side of the pole ear connection part 212 facing the electrode assembly 23 is flush with the surface of the side of the shell connection part 213 facing the electrode assembly 23.

[0125] In the embodiment of the present application, the thickness of the tab connection portion 212 may be the same as or different from the thickness of the shell connection portion 213 , but the surface of the current collecting end cover 21 facing the electrode assembly 23 is a flat surface.

[0126] In the embodiment of the present application, by making the side of the pole ear connection portion 212 facing the electrode assembly 23 flush with the surface of the side of the shell connection portion 213 facing the electrode assembly 23, the height of the current collecting end cover 21 can be reduced while maintaining the strength of the current collecting end cover 21, thereby making the capacity of the accommodating cavity of the shell 22 larger, thereby reducing the height of the battery cell 20.

[0127] According to some embodiments of the present application, the base metals of the tab connection portion 212 and the shell connection portion 213 are different.

[0128] In the embodiments of the present application, base metal refers to the main component metal in a material (such as an alloy or composite material), such as a metal element with a mass fraction greater than 50%. The performance of different base metal materials will also vary to a certain extent. The tab connection portion 212 needs to be connected to the first tab 241. When selecting materials and processing, it is necessary to consider the welding process requirements and electrical conductivity requirements when welding with the first tab 241; the shell connection portion 213 needs to be connected to the shell 22, and it is necessary to consider the structural strength requirements as a battery end cover. By reasonably selecting the material type according to the performance requirements of the tab connection portion 212 and the shell connection portion 213 respectively, the base metal of the tab connection portion 212 and the shell connection portion 213 can be different. In this way, the tab connection portion 212 can meet the reliable connection and overcurrent problems with the first tab 241, while the shell connection portion 213 can meet the overall structural strength requirements of the collecting end cover 21.

[0129] In the embodiment of the present application, by setting the base metals of the tab connection part 212 and the shell connection part 213 to be different, the different connection requirements of the tab connection part 212 and the shell connection part 213 and the overall strength requirements of the collecting end cover 21 can be better taken into account, thereby improving the performance and reliability of the battery cell 20.

[0130] According to some embodiments of the present application, the base metal of the tab connection portion 212 is copper; and the base metal of the shell connection portion 213 is iron or aluminum.

[0131] In the embodiment of the present application, copper has good electrical conductivity and corrosion resistance, and can quickly conduct electrons during electrochemical reactions. The base metal of the tab connection portion 212 is copper, so that when the tab connection portion 212 is connected to the first tab 241, the current flow capacity of the tab connection portion 212 and the first tab 241 is met. Materials with copper as the base metal include pure copper, nickel-plated copper, iron-plated copper, copper-nickel composite materials, copper-iron composite materials, and the like.

[0132] Iron is a common material with advantages such as durability, corrosion resistance, and low cost. Materials with iron as the base metal primarily include various types of steel, such as stainless steel and nickel-plated steel. Aluminum, with its strength, high temperature resistance, and long service life, includes aluminum or aluminum alloys. Materials with iron or aluminum as the base metal are relatively strong and can meet the structural strength requirements of the current collecting end cap 21 when used as the housing connection portion 213.

[0133] In the embodiment of the present application, by making the base metal of the tab connection portion 212 copper and the base metal of the shell connection portion 213 iron or aluminum, the flow capacity and structural strength of the collecting end cover 21 can be improved, thereby improving the reliability of the battery cell 20.

[0134] According to some embodiments of the present application, the base metal of the tab connection portion 212 and the shell connection portion 213 is the same.

[0135] In the embodiment of the present application, the base metal of the tab connection portion 212 and the shell connection portion 213 of the current collecting end cover 21 is the same, which means that the materials of the two are similar or even the same, that is, when preparing the current collecting end cover 21, the tab connection portion 212 and the shell connection portion 213 can be integrally formed with the same material. For example, the current collecting end cover 21 can be manufactured by stamping or the like. The current collecting end cover 21 serves as both an end cover and a current collecting plate, which can make the structure of the current collecting end cover 21 simpler, thereby simplifying the production process of the current collecting end cover 21 and reducing the manufacturing cost of the current collecting end cover 21. In other examples, the base metal of the tab connection portion 212 and the shell connection portion 213 is the same, but different processing techniques, such as heat treatment, can be used to make the performance of the tab connection portion 212 and the shell connection portion 213 somewhat different, thereby meeting the different performance requirements of the two.

[0136] In the embodiment of the present application, the base metals of the tab connection portion 212 and the shell connection portion 213 are set to be the same, which can simplify the preparation of the collecting end cover 21 and reduce the risk of unreliable connection between the tab connection portion 212 and the shell connection portion 213.

[0137] According to some embodiments of the present application, the base metal of the tab connection portion 212 and the shell connection portion 213 is copper.

[0138] In the embodiments of the present application, copper has excellent electrical conductivity and can quickly conduct electrons during electrochemical reactions. It is also highly corrosion-resistant. It is understood that the fact that the base metal of the tab connection portion 212 and the shell connection portion 213 is copper does not mean that the two materials are identical. Different properties can also be achieved by doping different elements to form different alloys or composite materials. In some examples, the tab connection portion 212 can be copper, and the shell connection portion 213 can be a copper alloy or copper composite material, such as nickel-plated copper.

[0139] In the embodiment of the present application, copper is selected as the base metal of the tab connection portion 212 and the shell connection portion 213 , which can improve the flow capacity and corrosion resistance of the collecting end cover 21 and improve the reliability of the battery cell 20 .

[0140] According to some embodiments of the present application, the maximum thickness of the tab connection portion 212 is d1, the minimum thickness of the shell connection portion 213 is d2, and d1≤d2 is satisfied.

[0141] In the embodiments of the present application, due to factors such as the manufacturing process and the material, the thickness of the tab connection portion 212 and the shell connection portion 213 may be uneven. Figure 11 is a seventh structural schematic diagram of the current collecting end cap 21 of some embodiments of the present application. As shown in Figure 11, the second direction Y is the same as the thickness direction of the current collecting end cap 21. The maximum thickness d1 is the maximum dimension of the tab connection portion 212 along the second direction Y, and the minimum thickness d2 is the minimum dimension of the shell connection portion 213 along the second direction Y. d1 ≤ d2 means that the thickness of the shell connection portion 213 is greater than the thickness of the tab connection portion 212.

[0142] In the embodiment of the present application, the greater the thickness of the component, the greater the bending strength of the component. The maximum thickness d1 of the tab connection portion 212 is less than or equal to the minimum thickness d2 of the shell connection portion 213. In fact, it is equivalent to enhancing the overall strength and deformation resistance of the current collecting end cover 21 by increasing the thickness of the shell connection portion 213. At the same time, the smaller thickness of the tab connection portion 212 is conducive to reducing the internal resistance and the weight of the current collecting end cover 21, thereby improving the performance of the battery cell 20.

[0143] According to some embodiments of the present application, the maximum thickness of the tab connection portion 212 is d1, the minimum thickness of the shell connection portion 213 is d2, and the following relationship is satisfied: 0.5≤d1 / d2≤1.

[0144] In the embodiment of the present application, if the ratio of the maximum thickness d1 of the tab connection portion 212 to the minimum thickness d2 of the shell connection portion 213 is too small, that is, if the maximum thickness d1 of the tab connection portion 212 is too thin compared to the minimum thickness d2 of the shell connection portion 213, the overall structural strength of the current collecting end cap 21 will be weakened. After electrical connection, gas generation from the battery cells 20 will cause the current collecting end cap 21 to bulge or even deform. If the ratio is too large, it will lead to unnecessary weight increase, which is not conducive to improving the battery energy density.

[0145] Optionally, d1 / d2 can be 0.5, 0.6, 0.7, 0.8, 0.9 or 1, etc.

[0146] In the embodiment of the present application, by controlling the ratio of the thickness d1 of the tab connection portion 212 to the thickness d2 of the shell connection portion 213 within an appropriate range, the structural strength of the collecting end cover 21 and the energy density of the battery cell 20 can be taken into account, thereby improving the performance of the battery cell 20.

[0147] According to some embodiments of the present application, the ratio a of the projected area of ​​the tab connection portion 212 on the first plane 25 to the projected area of ​​the current collecting end cover 21 on the first plane 25 satisfies: 0.1≤a≤0.95, wherein the first plane 25 is a plane perpendicular to the thickness direction of the current collecting end cover 21.

[0148] In the embodiment of the present application, the collecting end cover 21 is a roughly flat structure, and the first plane 25 is a plane perpendicular to the thickness direction of the collecting end cover 21. As shown in Figure 11, the first plane 25 is perpendicular to the second direction Y and parallel to the first direction X. The second direction Y is the same as the thickness direction of the collecting end cover 21.

[0149] The projected area of ​​the tab connection portion 212 on the first plane 25 is A1, and the projected area of ​​the current collecting end cap 21 on the first plane 25 is A2. The ratio a between the two satisfies a = A1 / A2. A larger a means a larger proportion of the area of ​​the tab connection portion 212 within the current collecting end cap 21. Because the tab connection portion 212 is more important for the reliability of the electrical connection with the first tab 241 and the current carrying capacity, an excessively large a can negatively impact the overall strength of the current collecting end cap 21, while an excessively small a can also adversely affect the reliability of the connection with the first tab 241 and the current carrying capacity.

[0150] Optionally, the ratio a of the projected area of ​​the tab connection portion 212 on the first plane 25 to the projected area of ​​the current collecting end cover 21 on the first plane 25 may be 0.1, 0.3, 0.5, 0.7 or 0.95, etc.

[0151] In the embodiment of the present application, limiting the ratio a of the projected area of ​​the tab connection portion 212 on the first plane 25 to the projected area of ​​the current collecting end cover 21 on the first plane 25 within an appropriate range can better balance the connection reliability and current flow capacity between the current collecting end cover 21 and the first tab 241, as well as the overall structural strength, thereby improving the reliability of the current collecting end cover 21.

[0152] According to some embodiments of the present application, a ratio a of a projected area of ​​the tab connection portion 212 on the first plane 25 to a projected area of ​​the current collecting end cap 21 on the first plane 25 satisfies: 0.4≤a≤0.6.

[0153] Optionally, the ratio a of the projected area of ​​the tab connection portion 212 on the first plane 25 to the projected area of ​​the current collecting end cover 21 on the first plane 25 may be 0.4, 0.5, 0.6, or the like.

[0154] In the embodiment of the present application, by setting the area ratio a of the tab connection portion 212 to the current collecting end cover 21 between 0.4 and 0.6, the current collecting end cover 21 has more uniform capabilities in terms of flow capacity, connection reliability, and structural strength.

[0155] According to some embodiments of the present application, the collecting end cover 21 also includes a structural reinforcement portion 2133, which is located at one end of the shell connecting portion 213 close to the shell 22. Along the thickness direction of the collecting end cover 21, the maximum dimension d3 of the structural reinforcement portion 2133 is greater than the maximum thickness d4 of the shell connecting portion 213.

[0156] In the embodiment of the present application, the structural reinforcement portion 2133 can be integrally formed with the housing connection portion 213, or even integrally formed with the tab connection portion 212, and can be formed into different thicknesses or structural forms through subsequent processing. Alternatively, the structural reinforcement portion 2133 can be manufactured separately and connected to the housing connection portion 213 to form a complete current collecting end cap 21.

[0157] The structural reinforcement portion 2133 can be implemented by thickening a local portion of the current collecting end cover 21. For example, FIG12 is a schematic structural diagram eight of the current collecting end cover 21 according to some embodiments of the present application. As shown in FIG12 , a structural reinforcement portion 2133 is provided on the periphery of the shell connecting portion 213 of the current collecting end cover 21. Along a second direction Y that is the same as the thickness direction of the current collecting end cover 21, the maximum dimension d3 of the structural reinforcement portion 2133 is greater than the maximum thickness d4 of the shell connecting portion 213.

[0158] Figure 13 is a ninth structural diagram of the current collecting end cap 21 according to some embodiments of the present application. As shown in Figure 13 , it is understood that the maximum dimension d3 of the structural reinforcement portion 2133 may be a localized dimension, allowing the structural reinforcement portion 2133 to simultaneously have a dimension along the second direction Y that is smaller than the maximum thickness d4 of the housing connection portion 213. The structural reinforcement portion 2133 may be one or more folds stamped into a plate-like structure, wherein the maximum dimension d3 along the second direction Y is greater than the maximum thickness d4 of the housing connection portion 213.

[0159] In the embodiment of the present application, by adding a structural reinforcement portion 2133 to the shell connection portion 213, the overall strength of the collecting end cover 21 can be increased and the deformation resistance of the collecting end cover 21 can be improved, which is not only beneficial for installation positioning and welding positioning during connection, but also beneficial for improving the structural reliability of the battery cell 20.

[0160] According to some embodiments of the present application, the structural reinforcement portion 2133 includes at least one third protrusion 2134 , which protrudes away from the electrode assembly 23 relative to the shell connection portion 213 or protrudes toward the electrode assembly 23 relative to the shell connection portion 213 .

[0161] In the embodiment of the present application, the structural reinforcement portion 2133 can also be realized by providing a protrusion on the collecting end cover 21.

[0162] For example, as shown in FIG13 , the structural reinforcement portion 2133 may include a third protrusion 2134 , which protrudes relative to the housing connection portion 213 in a direction away from the electrode assembly 23 . The number of third protrusions 2134 may be one or more, and the shape of the third protrusion 2134 may be arbitrary, and this embodiment does not limit this. In other examples, the third protrusion 2134 may also protrude in a direction closer to the electrode assembly 23 .

[0163] In the embodiment of the present application, the structural reinforcement portion 2133 is formed by providing a third protrusion 2134, which can simplify the structural form of the structural reinforcement portion 2133, facilitate processing and manufacturing, and reduce unnecessary weight increase while providing strength support.

[0164] According to some embodiments of the present application, the projection of the third protrusion 2134 on the first plane 25 is annular, wherein the first plane 25 is a plane perpendicular to the thickness direction of the current collecting end cover 21 .

[0165] In some examples, Figure 14 is a top view of Figure 13. As shown in Figure 14, the collecting end cover 21 can be a circular end cover, and the third protrusion 2134 can be continuously arranged along the outer periphery of the shell connecting portion 213 to form an annular reinforcement portion, which can further increase the structural strength of the collecting end cover 21.

[0166] According to some embodiments of the present application, there are multiple third protrusions 2134 , which are spaced apart along the first direction X. The first direction X is the direction from the center of the current collecting end cover 21 to the edge of the current collecting end cover 21 .

[0167] In the embodiment of the present application, the distance between two adjacent third protrusions 2134 can be the same or different, and this embodiment does not limit this.

[0168] In the embodiment of the present application, by providing a plurality of third protrusions 2134 along the direction X pointing from the center of the current collecting end cover 21 to the edge of the current collecting end cover 21 , compared with increasing the overall thickness, it is possible to more effectively balance the strength requirements and energy density requirements, thereby improving the overall performance of the battery cell 20 .

[0169] According to some embodiments of the present application, as shown in Figure 11, the ratio of the projected area A1 of the pole tab connection portion 212 on the first plane 25 to the projected area A2 of the current collecting end cover 21 on the first plane 25 is a, and the minimum thickness of the pole tab connection portion 212 along the thickness direction of the current collecting end cover 21 is d0, wherein 0.05≤d0 / a≤40, wherein the first plane 25 is a plane perpendicular to the thickness direction of the current collecting end cover 21.

[0170] In this embodiment of the present application, the weld mark area where the tab connection portion 212 connects to the first tab 241 can serve as a relatively weak structural area, rupturing when the internal pressure of the battery cell 20 reaches a certain preset threshold, thereby acting as an explosion-proof valve. At the same time, due to the influence of the manufacturing process, the thickness of the tab connection portion 212 along the second direction Y, which is the same as the thickness direction of the current collecting end cap 21, varies to a certain extent.

[0171] The ratio (a) of the projected area A1 of the tab connection 212 on the first plane 25 to the projected area A2 of the current collecting end cap 21 on the first plane 25, and the minimum thickness (d0) of the tab connection 212 along the second direction Y, which is the same as the thickness direction of the current collecting end cap 21, will both affect the strength of the explosion-proof valve in the region of the battery cell 20 where the tab connection 212 is located, as it functions as a valve opening device. Specifically, if the minimum thickness (d0) of the tab connection 212 along the thickness direction of the current collecting end cap 21 is too large, or if the ratio (a) of the projected area A1 of the tab connection 212 on the first plane 25 to the total projected area A2 of the current collecting end cap 21 on the first plane 25 is too small, the explosion-proof valve will be too strong, making it difficult to open the valve in a timely manner under adverse conditions such as thermal runaway or excessive internal pressure in the battery cell 20, potentially leading to rupture of the housing 22. If the minimum thickness d0 of the tab connection portion 212 along the thickness direction of the current collecting end cap 21 is too small, or if the ratio a between the projected area A1 of the tab connection portion 212 on the first plane 25 and the total projected area A2 of the current collecting end cap 21 on the first plane 25 is too large, the explosion-proof valve strength may be too weak. During the production and use of the battery cell 20, the explosion-proof valve may open uncontrollably due to other external forces, resulting in battery cell 20 leakage, abnormal electrical connections, etc. Optionally, the value of d0 / a can be 0.05, 0.1, 1, 5, 10, 20, or 40, etc.

[0172] In some embodiments, the current collecting end cap 21 further includes at least one pressure relief portion configured to relieve pressure when the pressure within the accommodating cavity of the battery cell 20 is greater than or equal to a preset threshold. For example, FIG15 is a top view of the current collecting end cap of other embodiments of the present application. As shown in FIG15 , the pressure relief portion can be a notch located on at least one of a first surface of the current collecting end cap 21 facing the electrode assembly 23 and a second surface facing away from the electrode assembly 23. The thickness of the portion where the notch is located is less than the thickness surrounding the notch.

[0173] In the embodiment of the present application, by setting the ratio a of the projected area A1 of the pole tab connection portion 212 on the first plane 25 to the projected area A2 of the current collecting end cover 21 on the first plane 25, and the ratio d0 of the minimum thickness of the pole tab connection portion 212 along the thickness direction of the current collecting end cover 21 to between 0.05 and 40, the area where the pole tab connection portion 212 is located can have suitable valve opening strength as an explosion-proof valve, thereby achieving more stable and reliable valve opening pressure relief, thereby improving the reliability of the battery cell 20.

[0174] According to some embodiments of the present application, the value of d0 / a satisfies: 0.8≤d0 / a≤1.6.

[0175] Optionally, the value of d0 / a may be 0.8, 1.0, 1.2, 1.5 or 1.6, etc.

[0176] In the embodiment of the present application, by setting the ratio a of the projected area A1 of the pole tab connection portion 212 on the first plane 25 to the projected area A2 of the current collecting end cover 21 on the first plane 25, and the ratio d0 of the minimum thickness of the pole tab connection portion 212 along the thickness direction of the current collecting end cover 21 to between 0.8 and 1.6, the strength of the explosion-proof valve opening of the battery cell 20 can be within a more appropriate range, thereby improving the reliability of the battery cell 20.

[0177] According to some embodiments of the present application, Figure 16 is a structural schematic diagram of another battery cell of some embodiments of the present application. As shown in Figure 16, the shell 22 includes an end wall away from the opening, and the end wall is provided with a second through hole. The electrode assembly 23 also includes a second pole ear 242 close to the end wall, and the polarity of the second pole ear 242 is different from that of the first pole ear 241. The battery cell 20 also includes an electrode terminal 211, and the electrode terminal 211 is passed through the second through hole and electrically connected to the second pole ear 242.

[0178] In the embodiment of the present application, the electrode terminal 211 is an output component, such as a pole, for outputting the electrical energy of the battery cell 20. There can be one electrode terminal 211. For example, the first electrode tab 241 is a negative electrode tab, and the second electrode tab 242 is a positive electrode tab.

[0179] In the embodiment of the present application, the electrode terminal 211 is passed through the second through hole and electrically connected to the second pole ear 242, and the current collecting end cover 21 is electrically connected to the first pole ear 241, and the current collecting end cover 21 realizes an integrated design of the current collecting plate and the end cover, which can achieve a reliable electrical connection between the current collecting plate and the end cover before the battery is assembled, reducing the risk of cold welding during the assembly of the battery cell, thereby improving the reliability of the battery cell 20.

[0180] FIG17 is a flow chart of a method for manufacturing a battery cell according to some embodiments of the present application. As shown in FIG17 , the method for manufacturing a battery cell includes:

[0181] Step S1710: providing an electrode assembly, a shell and a current collecting end cover respectively, wherein the electrode assembly includes a first electrode tab, the shell is formed with a receiving cavity and an opening at one end of the receiving cavity, and the current collecting end cover includes a connected electrode tab connection portion and a shell connection portion.

[0182] Step S1720: Place the electrode assembly into the accommodating cavity of the shell.

[0183] Step S1730: welding the tab connection portion of the current collecting end cap to the first tab of the electrode assembly.

[0184] Step S1740: welding the shell connection portion of the collecting end cover to the shell.

[0185] In the embodiments of the present application, the battery cells may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, and the embodiments of the present application are not limited thereto. The battery cells may be cylindrical, flat, rectangular, or in other shapes, and the embodiments of the present application are not limited thereto.

[0186] The electrode assembly is the component within the battery cell where the electrochemical reaction occurs. The housing formed by the casing may contain one or more electrode assemblies. The current collecting end cap is a component that fits over the opening of the casing to isolate the battery cell housing from the external environment. The shape of the current collecting end cap can be adapted to the shape of the casing to ensure a compatible fit.

[0187] In the embodiment of the present application, the current collecting end cap includes a connected tab connection portion and a shell connection portion. The tab connection portion is connected to the first tab and functions as a current collecting plate. The shell connection portion is located on the side of the tab connection portion closest to the shell and is connected to the shell, so that the current collecting end cap serves as an end cap to close the opening of the shell. In other words, the current collecting end cap combines the functions of the current collecting plate and the end cap, forming an integrated structure of the current collecting plate and the end cap. The tab connection portion and the shell connection portion can be integrally formed or manufactured separately and then fixedly connected together.

[0188] In an embodiment of the present application, the electrode assembly is placed in the accommodating cavity of the shell, and the collecting end cover can first weld the pole tab connection part to the first pole tab, and then weld the shell connection part to the shell, such as laser welding or friction welding.

[0189] In an embodiment of the present application, during the assembly process of the battery cell, the current collecting end cover is a separate incoming part, and a reliable connection between the pole tab connection part and the shell connection part is achieved before being welded to the first pole tab and the shell. This can simplify the welding process during the assembly of the battery cell, reduce the risk of cold welding, and improve the reliability of the battery cell.

[0190] According to some embodiments of the present application, the aforementioned step S1730 includes: arranging the current collecting end cover at the opening of the shell so that the pole tab connecting portion abuts the first pole tab; emitting a laser from the side of the current collecting end cover away from the electrode assembly and penetrating the pole tab connecting portion so that the pole tab connecting portion is welded to the first pole tab.

[0191] In the embodiment of the present application, since the electrode assembly is located within the housing cavity within the housing, the corresponding first tab is also located within the housing. When the current collecting end cap is arranged at the opening of the housing, the tab connection portion can abut the first tab, and laser welding can be used to achieve a welded connection between the tab connection portion and the first tab. Specifically, the tab connection portion and the first tab are heated by laser radiation, and the surface heat diffuses inwardly through heat conduction. By controlling laser parameters such as the width, energy, peak power, and repetition frequency of the laser pulse, the laser penetrates the tab connection portion and melts the first tab, thereby achieving a welded connection between the tab connection portion and the first tab.

[0192] In an embodiment of the present application, the current collecting end cover is arranged at the opening of the shell so that the pole tab connecting portion abuts the first pole tab, and the laser is emitted from the side of the current collecting end cover away from the electrode assembly and penetrates the pole tab connecting portion so that the pole tab connecting portion is welded to the first pole tab, further simplifying the welding process of the battery cell.

[0193] An embodiment of the present application provides a battery 100 , which includes the battery cell 20 in the above embodiment.

[0194] By adopting the battery cell 20 in the embodiment of the present application, the probability of cold welding between the current collecting plate and the end cover caused by penetration welding can be reduced, thereby improving the safety and reliability of the battery cell 20.

[0195] An embodiment of the present application provides an electrical device, which includes the battery 100 in the above embodiment, and the battery 100 is used to provide electrical energy.

[0196] The technical solution of the present application is further described below by using a specific embodiment, as shown in FIG1 to FIG15 .

[0197] The battery cell 20 includes an electrode assembly 23, a housing 22, and a current collecting end cap 21. The electrode assembly 23 includes a first electrode tab 241. The housing 22 has a cavity and an opening at one end thereof for accommodating the electrode assembly 23. The current collecting end cap 21 is connected to the housing 22 to seal the opening. The current collecting end cap 21 includes a connected electrode tab connection portion 212 and a housing connection portion 213. The electrode tab connection portion 212 is connected to the first electrode tab 241, and the housing connection portion 213 is connected to the housing 22. The electrode tab connection portion 212 is welded to the first electrode tab 241 to form a weld region Q. The weld region Q, when projected onto the current collecting end cap 21, is offset from the housing connection portion 213.

[0198] The shell 22 includes an end wall away from the opening, and the end wall is provided with a second through hole. The electrode assembly 23 also includes a second pole ear 242 close to the end wall. The polarity of the second pole ear 242 is different from that of the first pole ear 241. The battery cell 20 also includes an electrode terminal 211, which is passed through the second through hole and is electrically connected to the second pole ear 242.

[0199] The fracture elongation of the tab connection portion 212 is less than the fracture elongation of the shell connection portion 213, and the ratio S of the fracture elongation of the shell connection portion 213 to the fracture elongation of the tab connection portion 212 satisfies 1.1≤S≤2.2, the fracture elongation S1 of the tab connection portion 212 satisfies 0.2≤S1≤0.3, and the fracture elongation S2 of the shell connection portion 213 satisfies 0.35≤S2≤0.45.

[0200] The tab connection portion 212 includes a first main body 2121 and a first connection portion 2122 connected to the first main body 2121 and arranged along the outer edge of the first main body 2121; the shell connection portion 213 includes a second connection portion 2131 and a first through hole, the orthographic projection of the first main body 2121 on the shell connection portion 213 is located in the first through hole, and the first connection portion 2122 is welded to the second connection portion 2131.

[0201] In some embodiments, the first connection portion 2122 includes a first protrusion extending away from or toward the electrode assembly 23. Along the first direction X, the first protrusion abuts against the second connection portion 2131. The first direction X is the direction from the center of the current collecting end cover 21 to the edge of the current collecting end cover 21.

[0202] In some embodiments, the second connection portion 2131 includes a second protrusion extending away from or toward the electrode assembly 23, and along the first direction X, the second protrusion abuts against the first connection portion 2122, and the first direction X is the direction from the center of the current collecting end cover 21 to the edge of the current collecting end cover 21.

[0203] In some embodiments, the first connection portion 2122 includes a first protrusion extending in a direction away from the electrode assembly 23, and the second connection portion 2131 includes a second protrusion extending in a direction close to the electrode assembly 23, and along the first direction X, the first protrusion abuts the second protrusion, and the first direction X is the direction from the center of the current collecting end cover 21 to the edge of the current collecting end cover 21; or, the first connection portion 2122 includes a second protrusion extending in a direction close to the electrode assembly 23, and along the first direction X, the first protrusion abuts the second protrusion, and the first direction X is the direction from the center of the current collecting end cover 21 to the edge of the current collecting end cover 21.

[0204] In some embodiments, the tab connection portion 212 is flat, and the orthographic projection of the first connection portion 2122 on the housing connection portion 213 at least partially overlaps with the second connection portion 2131. The side of the tab connection portion 212 facing the electrode assembly 23 is flush with the surface of the side of the housing connection portion 213 facing the electrode assembly 23.

[0205] The base metals of the tab connection part 212 and the shell connection part 213 are different, for example, the base metal of the tab connection part 212 is copper, and the base metal of the shell connection part 213 is iron or aluminum; or the base metals of the tab connection part 212 and the shell connection part 213 are the same, for example, the base metals of the tab connection part 212 and the shell connection part 213 are copper.

[0206] The maximum thickness of the tab connection portion 212 is d1, the minimum thickness of the shell connection portion 213 is d2, and d1≤d2, 0.5≤d1 / d2≤1 are satisfied.

[0207] The ratio a of the projected area of ​​the tab connection portion 212 on the first plane 25 to the projected area of ​​the current collecting end cover 21 on the first plane 25 satisfies: 0.4≤a≤0.6, wherein the first plane 25 is a plane perpendicular to the thickness direction of the current collecting end cover 21 .

[0208] The current collecting end cap 21 also includes a structural reinforcement 2133 located at one end of the housing connection portion 213 proximal to the housing 22. Along the thickness direction of the current collecting end cap 21, the maximum dimension d3 of the structural reinforcement 2133 is greater than the maximum thickness d4 of the housing connection portion 213. The structural reinforcement 2133 includes at least one third protrusion 2134, which projects away from the electrode assembly 23 relative to the housing connection portion 213 or toward the electrode assembly 23 relative to the housing connection portion 213. The projection of the third protrusion 2134 onto the first plane 25 is annular. There are multiple third protrusions 2134, which are spaced apart along a first direction X, which is the direction from the center of the current collecting end cap 21 to the edge of the current collecting end cap 21.

[0209] The ratio of the projected area of ​​the tab connection portion 212 on the first plane 25 to the projected area of ​​the current collecting end cover 21 on the first plane 25 is a. The minimum thickness of the tab connection portion 212 along the thickness direction of the current collecting end cover 21 is d0, where 0.05≤d0 / a≤40, and the first plane 25 is a plane perpendicular to the thickness direction of the current collecting end cover 21. The value of d0 / a satisfies the following: 0.8≤d0 / a≤1.6.

[0210] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell, comprising: An electrode assembly including a first electrode tab; A shell, formed with a receiving cavity and an opening at one end of the receiving cavity, wherein the receiving cavity is used to receive the electrode assembly; A current collecting end cover is connected to the shell to close the opening, and the current collecting end cover includes a connected pole lug connection portion and a shell connection portion, the pole lug connection portion is connected to the first pole lug, and the shell connection portion is connected to the shell.

2. The battery cell according to claim 1, wherein: The pole tab connection portion is welded to the first pole tab to form a welding area, and a projection of the welding area on the current collecting end cover is staggered with the shell connection portion.

3. The battery cell according to claim 1 or 2, wherein: The elongation at break of the tab connection portion is smaller than the elongation at break of the shell connection portion.

4. The battery cell according to any one of claims 1 to 3, wherein: A ratio S of the elongation at break of the shell connection portion to the elongation at break of the tab connection portion satisfies 1.1≤S≤2.

2.

5. The battery cell according to any one of claims 1 to 4, wherein: The elongation at break S1 of the tab connection portion satisfies 0.2≤S1≤0.3, and the elongation at break S2 of the shell connection portion satisfies 0.35≤S2≤0.

45.

6. The battery cell according to any one of claims 1 to 5, wherein: The tab connection portion includes a first main body and a first connection portion connected to the first main body and arranged along the outer edge of the first main body; The shell connecting portion includes a second connecting portion and a first through hole, the orthographic projection of the first body on the shell connecting portion is located in the first through hole, and the first connecting portion is welded to the second connecting portion.

7. The battery cell according to claim 6, wherein: The first connection portion includes a first protrusion extending in a direction away from or close to the electrode assembly. Along a first direction, the first protrusion abuts against the second connection portion. The first direction is a direction from the center of the current collecting end cover to the edge of the current collecting end cover.

8. The battery cell according to claim 6, wherein: The second connection portion includes a second protrusion extending in a direction away from or close to the electrode assembly, and the second protrusion abuts against the first connection portion along a first direction, and the first direction is a direction from the center of the current collecting end cover to the edge of the current collecting end cover.

9. The battery cell according to claim 6, wherein: The first connecting portion includes a first protrusion extending in a direction away from the electrode assembly, and the second connecting portion includes a second protrusion extending in a direction close to the electrode assembly, and along a first direction, the first protrusion abuts against the second protrusion, and the first direction is a direction from the center of the current collecting end cover to the edge of the current collecting end cover; or, the first connecting portion includes a second protrusion extending in a direction close to the electrode assembly, and along the first direction, the first protrusion abuts against the second protrusion, and the first direction is a direction from the center of the current collecting end cover to the edge of the current collecting end cover.

10. The battery cell according to claim 6, wherein: The tab connection portion is in a flat plate shape, and the orthographic projection of the first connection portion on the shell connection portion at least partially overlaps with the second connection portion.

11. The battery cell according to claim 6, wherein: A side of the electrode tab connection portion facing the electrode assembly is flush with a surface of a side of the shell connection portion facing the electrode assembly.

12. The battery cell according to any one of claims 1 to 11, wherein: The base metals of the tab connection portion and the shell connection portion are different.

13. The battery cell according to claim 12, wherein: The base metal of the tab connection part is copper; the base metal of the shell connection part is iron or aluminum.

14. The battery cell according to any one of claims 1 to 11, wherein: The base metal of the tab connection portion is the same as that of the shell connection portion.

15. The battery cell according to claim 14, wherein: The base metal of the tab connection portion and the shell connection portion is copper.

16. The battery cell according to any one of claims 1 to 15, wherein: The maximum thickness of the tab connection portion is d1, the minimum thickness of the shell connection portion is d2, and d1≤d2 is satisfied.

17. The battery cell according to claim 16, wherein: The maximum thickness of the tab connection portion is d1, the minimum thickness of the shell connection portion is d2, and the following relationship is satisfied: 0.5≤d1 / d2≤1.

18. The battery cell according to any one of claims 1 to 17, wherein: A ratio a of a projected area of ​​the tab connection portion on a first plane to a projected area of ​​the current collecting end cover on a first plane satisfies: 0.1≤a≤0.95, wherein the first plane is a plane perpendicular to a thickness direction of the current collecting end cover.

19. The battery cell according to claim 18, wherein: A ratio a of a projected area of ​​the electrode tab connection portion on the first plane to a projected area of ​​the current collecting end cover on the first plane satisfies: 0.4≤a≤0.

6.

20. The battery cell according to any one of claims 1 to 19, wherein: The current collecting end cover also includes a structural reinforcement portion, which is located at one end of the shell connecting portion close to the shell. Along the thickness direction of the current collecting end cover, the maximum size of the structural reinforcement portion is greater than the maximum thickness of the shell connecting portion.

21. The battery cell according to claim 20, wherein: The structural reinforcement portion includes at least one third protrusion, and the third protrusion protrudes in a direction away from the electrode assembly relative to the shell connection portion or protrudes in a direction close to the electrode assembly relative to the shell connection portion.

22. The battery cell according to claim 21, wherein: The projection of the third protrusion on the first plane is annular, wherein the first plane is a plane perpendicular to the thickness direction of the current collecting end cover.

23. The battery cell according to claim 21 or 22, wherein: There are multiple third protrusions, which are arranged at intervals along a first direction, and the first direction is a direction from the center of the current collecting end cover to the edge of the current collecting end cover.

24. The battery cell according to any one of claims 1 to 23, wherein: The ratio of the projection area of ​​the pole tab connection portion on the first plane to the projection area of ​​the current collecting end cover on the first plane is a, and the minimum thickness of the pole tab connection portion along the thickness direction of the current collecting end cover is d0, wherein 0.05≤d0 / a≤40, wherein the first plane is a plane perpendicular to the thickness direction of the current collecting end cover.

25. The battery cell according to claim 24, wherein: The value of d0 / a satisfies: 0.8≤d0 / a≤1.

6.

26. The battery cell according to any one of claims 1 to 25, wherein: The housing comprises an end wall away from the opening, wherein the end wall is provided with a second through hole, The electrode assembly further includes a second electrode tab adjacent to the end wall, wherein the second electrode tab has a different polarity from the first electrode tab. The battery cell further includes an electrode terminal, which is disposed through the second through hole and is electrically connected to the second electrode tab.

27. A method for manufacturing a battery cell, comprising: An electrode assembly, a shell and a current collecting end cover are respectively provided, wherein the electrode assembly includes a first electrode tab, the shell is formed with a receiving cavity and an opening at one end of the receiving cavity, and the current collecting end cover includes a connected electrode tab connection portion and a shell connection portion; placing the electrode assembly into the accommodating cavity of the shell; Welding the tab connection portion of the current collecting end cap to the first tab of the electrode assembly; The shell connecting portion of the current collecting end cover is welded to the shell.

28. The method according to claim 27, wherein: The step of welding the tab connection portion of the current collecting end cap to the first tab of the electrode assembly comprises: Arranging the current collecting end cover at the opening of the housing so that the pole tab connecting portion abuts against the first pole tab; The laser is emitted from a side of the current collecting end cover away from the electrode assembly and penetrates the pole tab connecting portion so that the pole tab connecting portion is welded to the first pole tab.

29. A battery comprising the battery cell according to any one of claims 1 to 26.

30. An electrical device, comprising the battery as claimed in claim 29, wherein the battery is used for providing electrical energy.

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