Battery cell, battery, and electric device

Abstract

The application provides a battery monomer, a battery and a power utilization device, and belongs to the technical field of batteries. The battery monomer comprises an electrode assembly, a shell and a current collecting end cover. The electrode assembly comprises a first tab, the shell is formed with an accommodating cavity and an opening at one end of the accommodating cavity, the accommodating cavity is used for accommodating the electrode assembly, the current collecting end cover is connected with the shell to close the opening, the current collecting end cover comprises a tab connecting part and a shell connecting part which are connected with each other, the tab connecting part is connected with the first tab, and the shell connecting part is connected with the shell.

Description

[0001] Cross-referencing

[0002] This application incorporates 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] This application relates to the field of battery technology, and in particular to a battery cell, a battery, and an electrical device. Background Technology

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

[0005] In existing battery structures, the tabs of a battery cell are usually welded to the current collector first, then the current collector is welded to the end cover, and finally the end cover is welded to the housing. This not only involves many welding steps, but also makes it easy for incomplete welds to occur between the current collector and the end cover, which in turn affects the performance and reliability of the battery cell. Summary of the Invention

[0006] This application aims to at least address one of the technical problems existing in the background art. Therefore, one object of this application is to provide a battery cell, a battery, and an electrical device to improve the reliability of the battery cell.

[0007] An embodiment of the first aspect of this application provides a battery cell, which includes an electrode assembly, a housing, and a current collector cap. The electrode assembly includes a first tab; the housing has a receiving cavity and an opening at one end of the receiving cavity, the receiving cavity being used to receive the electrode assembly; the current collector cap is connected to the housing to close the opening, and the current collector cap includes a connected tab connection portion and a housing connection portion, the tab connection portion being connected to the first tab, and the housing connection portion being connected to the housing.

[0008] In the technical solution of this application embodiment, a reliable connection between the electrode connection part and the housing connection part can be completed before the electrode connection part and the first electrode connection step. This not only reduces the number of parts during battery assembly and simplifies the welding process, but also reduces the risk of poor welding and improves the reliability of the battery cell.

[0009] In some embodiments, the tab connection portion is welded to the first tab to form a welding area, and the projection of the welding area on the current collector cover is offset from that of the housing connection portion. This offset projection of the welding area formed by the tab connection portion and the first tab on the current collector cover is more conducive to the connection of the current collector cover to both the first tab and the housing, simplifies the manufacturing process of the battery cell, reduces the weight of the current collector cover, and helps to improve the energy density of the battery cell.

[0010] In some embodiments, the elongation at break of the housing connection is less than that of the tab connection. By setting the elongation at break of the tab connection to be less than that of the housing connection, the different connection requirements of the tab connection and the housing connection, as well as the overall structural strength requirements of the current collector cover, can be better balanced. At the same time, the tab connection will preferentially rupture when the internal pressure of the battery cell is high in order to release pressure, thereby improving the reliability of the battery cell.

[0011] In some embodiments, the ratio S of the elongation at break of the housing connection to the elongation at break of the tab connection satisfies 1.1 ≤ S ≤ 2.2. By setting the ratio S of the elongation at break of the housing connection to the elongation at break of the tab connection to satisfy 1.1 ≤ S ≤ 2.2, the stability and service life of the current collector end cover can be considered while meeting the structural strength and connection requirements of the current collector end cover.

[0012] In some embodiments, the elongation at break S1 of the tab connection portion satisfies 0.2 ≤ S1 ≤ 0.3, and the elongation at break S2 of the housing connection portion satisfies 0.35 ≤ S2 ≤ 0.45. Appropriate selection of the elongation at break of the tab connection portion and the housing connection portion allows the current collector end cap to meet both connection requirements and structural strength requirements.

[0013] In some embodiments, the tab connection includes a first body and a first connecting portion connected to the first body and disposed along the outer edge of the first body; the housing connection includes a second connecting portion and a first through hole, the orthographic projection of the first body on the housing connection is located within the first through hole, and the first connecting portion and the second connecting portion are welded together. By providing a first through hole on the housing connection, the orthographic projection of the first body included in the tab connection is located within the first through hole, and the first connecting portion and the second connecting portion are welded together, the integral molding of the current collector end cap can be better achieved, thereby reducing the risk of incomplete soldering between the current collector and the end cap caused by using through soldering, simplifying the manufacturing process and reducing manufacturing costs.

[0014] In some embodiments, the first connecting portion includes a first protrusion extending in a direction away from or towards the electrode assembly, and the first protrusion abuts against the second connecting portion along a first direction, the first direction being the direction from the center of the current collector cap to the edge of the current collector cap. By providing a first protrusion in the first connecting portion for connection with the housing connecting portion, a simpler and more reliable connection between the tab connecting portion and the housing connecting portion can be achieved.

[0015] In some embodiments, the second connection portion includes a second protrusion extending in a direction away from or towards the electrode assembly. Along a first direction, the second protrusion abuts against the first connection portion, whereby the direction is from the center of the current collector cap to the edge of the current collector cap. By providing a second protrusion in the second connection portion, the connection between the tab connection portion and the housing connection portion becomes simpler and more reliable.

[0016] 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 towards the electrode assembly. The first protrusion and the second protrusion abut against each other along a first direction, which is the direction from the center of the current collector cap to the edge of the current collector cap. Alternatively, the first connecting portion includes a second protrusion extending towards the electrode assembly, and the first protrusion and the second protrusion abut against each other along a first direction, which is the direction from the center of the current collector cap to the edge of the current collector cap. By providing a first protrusion on the first connecting portion and a second protrusion on the second connecting portion, the positioning between the first and second protrusions can reduce the precision requirements for operators when assembling the current collector cap, and also facilitates the welding process between the electrode tab connecting portion and the housing connecting portion, thereby achieving a more reliable connection.

[0017] In some embodiments, the tab connection portion is flat, and the orthographic projection of the first connection portion onto the housing connection portion at least partially overlaps with the second connection portion. By setting the tab connection portion as a flat plate and making the orthographic projection of the first connection portion onto the housing connection portion at least partially overlap with the second connection portion, the dimension of the current collector end cap along the thickness direction can be reduced while taking into account the connection positioning of the tab connection portion and the housing connection portion, which is beneficial to improving the energy density of the battery.

[0018] 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 collector can be reduced while maintaining the strength of the current collector, thereby increasing the capacity of the housing cavity and reducing the height of the battery cell.

[0019] In some embodiments, the base metal of the tab connection portion and the housing connection portion is different. By setting the base metal of the tab connection portion and the housing connection portion to be different, the different connection requirements of the tab connection portion and the housing connection portion, as well as the overall strength requirements of the current collector end cap, can be better taken into account, thereby improving the performance and reliability of the battery cell.

[0020] In some embodiments, the base metal of the tab connection portion is copper; the base metal of the housing 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 housing connection portion, the current carrying capacity and structural strength of the current collector cap can be improved, thereby enhancing the reliability of the battery cell.

[0021] In some embodiments, the base metal of the tab connection portion and the housing connection portion is the same. Setting the base metal of the tab connection portion and the housing connection portion to be the same can simplify the manufacturing of the current collector end cap and reduce the risk of unreliable connection between the tab connection portion and the housing connection portion.

[0022] In some embodiments, the base metal of the tab connection and the housing connection is copper. Using copper as the base metal for the tab connection and the housing connection can improve the current carrying capacity and corrosion resistance of the current collector cap, and improve the reliability of the battery cell.

[0023] In some embodiments, the maximum thickness of the tab connection is d1, the minimum thickness of the housing connection is d2, and d1 ≤ d2. The greater the component thickness, the greater the bending strength of the component. The maximum thickness d1 of the tab connection should be less than or equal to the minimum thickness d2 of the housing connection. In effect, this is equivalent to increasing the thickness of the housing connection to enhance the overall strength and deformation resistance of the current collector cap. At the same time, a smaller thickness of the tab connection helps to reduce internal resistance and the weight of the current collector cap, thereby improving the performance of the battery cell.

[0024] In some embodiments, the maximum thickness of the tab connection is d1, the minimum thickness of the housing connection is d2, and the following condition is met: 0.5 ≤ d1 / d2 ≤ 1. By controlling the ratio of the thickness d1 of the tab connection to the thickness d2 of the housing connection within a suitable range, the structural strength of the current collector cap and the energy density of the battery cell can be balanced, thereby improving the performance of the battery cell.

[0025] In some embodiments, the ratio 'a' of the projected area of ​​the tab connection portion on the first plane to the projected area 'a' of the current collector end cover on the first plane satisfies: 0.1 ≤ a ≤ 0.95, where the first plane is a plane perpendicular to the thickness direction of the current collector end cover. Limiting the ratio 'a' of the projected area of ​​the tab connection portion on the first plane to the projected area 'a' of the current collector end cover on the first plane within a suitable range better balances the connection reliability and current-carrying capacity between the current collector end cover and the first tab, as well as the overall structural strength, thereby improving the reliability of the current collector end cover.

[0026] In some embodiments, the ratio 'a' of the projected area of ​​the tab connection portion on the first plane to the projected area of ​​the collector end cover on the first plane satisfies: 0.4 ≤ a ≤ 0.6. By setting the area ratio 'a' of the tab connection portion to the collector end cover to 0.4 to 0.6, the current-carrying capacity, connection reliability, and structural strength of the collector end cover are made more uniform.

[0027] In some embodiments, the current collector cap further includes a structural reinforcement portion located at the end of the housing connection portion near the housing. Along the thickness direction of the current collector cap, the maximum dimension of the structural reinforcement portion is greater than the maximum thickness of the housing connection portion. By adding a structural reinforcement portion to the housing connection portion, the overall strength of the current collector cap can be increased, and its resistance to deformation can be improved. This not only facilitates installation and welding positioning during connection but also improves the structural reliability of the battery cell.

[0028] In some embodiments, the structural reinforcement includes at least one third protrusion, which protrudes away from the electrode assembly relative to the housing connection or protrudes closer to the electrode assembly relative to the housing connection. By providing a third protrusion, the structural reinforcement simplifies its structure, facilitates manufacturing, and reduces unnecessary weight gain while providing strength support.

[0029] In some embodiments, the projection of the third protrusion onto the first plane is annular, wherein the first plane is a plane perpendicular to the thickness direction of the collector end cover. The third protrusion may be continuously arranged along the outer periphery of the housing connection to form an annular reinforcing portion, which can further increase the structural strength of the collector end cover.

[0030] In some embodiments, there are multiple third protrusions, spaced apart along a first direction, which is the direction from the center of the current collector cap to the edge of the current collector cap. By providing multiple third protrusions along the direction from the center of the current collector cap to the edge of the current collector 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.

[0031] 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 collector cap on the first plane is 'a', and the minimum thickness of the tab connection portion along the thickness direction of the current collector cap is 'd0', where 0.05 ≤ d0 / a ≤ 40, and the first plane is a plane perpendicular to the thickness direction of the current collector cap. 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 collector cap on the first plane to the minimum thickness 'd0' of the tab connection portion along the thickness direction of the current collector cap between 0.05 and 40, the area where the tab connection portion is located can have suitable valve opening strength as an explosion-proof valve, thereby achieving more stable and reliable valve opening and pressure relief, and improving the reliability of the battery cell.

[0032] In some embodiments, the value of d0 / a satisfies: 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 collector end cover on the first plane to the minimum thickness d0 of the tab connection portion along the thickness direction of the current collector end cover between 0.8 and 1.6, the opening strength of the explosion-proof valve of the battery cell can be made within a more suitable range, thereby improving the reliability of the battery cell.

[0033] In some embodiments, the housing includes an end wall away from the opening, the end wall having a second through hole, and the electrode assembly further includes a second tab near the end wall, the second tab having a different polarity from the first tab. The battery cell also includes an electrode terminal, which passes through the through hole and is electrically connected to the second tab. By having the electrode terminal pass through the second through hole and be electrically connected to the second tab, the current collector end cap is electrically connected to the first tab. Furthermore, the current collector end cap achieves an integrated design of the current collector plate and the end cap, enabling a reliable electrical connection between the current collector plate and the end cap before battery assembly. This reduces the risk of poor soldering during battery cell assembly, thereby improving the reliability of the battery cell.

[0034] An embodiment of the second aspect of this application provides a method for manufacturing a battery cell. The method includes: providing an electrode assembly, a housing, and a current collector cap, wherein the electrode assembly includes a first tab, the housing has a receiving cavity and an opening at one end of the receiving cavity, the current collector cap includes a tab connection portion and a housing connection portion connected together, the electrode assembly is placed into the receiving cavity of the housing, the tab connection portion of the current collector cap is welded to the first tab of the electrode assembly, and the housing connection portion of the current collector cap is welded to the housing.

[0035] In the technical solution of this application embodiment, in the battery cell assembly process, the current collector end cap, as a separate incoming part, has already achieved a reliable connection between the electrode connection part and the housing connection part before welding with the first electrode and the housing. This can simplify the welding process during battery cell assembly, reduce the risk of false welding, and improve the reliability of the battery cell.

[0036] In some embodiments, welding the tab connection portion of the current collector cap to the first tab of the electrode assembly includes: arranging the current collector cap at the opening of the housing such that the tab connection portion abuts against the first tab; and emitting a laser from the side of the current collector 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 collector cap at the opening of the housing such that the tab connection portion abuts against the first tab, and emitting a laser from the side of the current collector 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 cell.

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

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

[0039] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0040] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout multiple drawings denote 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 this application and should not be considered as limiting the scope of this application. To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly described below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of the vehicle structure according to some embodiments of this application;

[0042] Figure 2 This is an exploded structural diagram of a battery according to some embodiments of this application;

[0043] Figure 3 This is an exploded structural diagram of a battery cell according to some embodiments of this application;

[0044] Figure 4 This is a schematic diagram of the structure of a battery cell according to some embodiments of this application;

[0045] Figure 5This is a schematic diagram of the structure of the current collector end cap in some embodiments of this application. Figure 1 ;

[0046] Figure 6 This is a schematic diagram of the structure of the current collector end cap in some embodiments of this application. Figure 2 ;

[0047] Figure 7 This is a schematic diagram of the structure of the current collector end cap in some embodiments of this application. Figure 3 ;

[0048] Figure 8 This is a schematic diagram of the structure of the current collector end cover in some embodiments of this application. Figure 4 ;

[0049] Figure 9 This is a schematic diagram of the structure of the current collector end cap in some embodiments of this application. Figure 5 ;

[0050] Figure 10 This is a schematic diagram of the structure of the current collector end cap in some embodiments of this application. Figure 6 ;

[0051] Figure 11 This is a schematic diagram of the structure of the current collector end cap in some embodiments of this application. Figure 7 ;

[0052] Figure 12 This is a schematic diagram of the structure of the current collector end cover in some embodiments of this application. Figure 8 ;

[0053] Figure 13 This is a schematic diagram of the structure of the current collector end cap in some embodiments of this application. Figure 9 ;

[0054] Figure 14 This is a top view of the current collection end cap of some embodiments of this application;

[0055] Figure 15 This is a top view of the current collection end cap of some other embodiments of this application;

[0056] Figure 16 This is a schematic diagram of the structure of another battery cell according to some embodiments of this application;

[0057] Figure 17 This is a flowchart illustrating a method for manufacturing a battery cell according to some embodiments of this application.

[0058] Explanation of reference numerals in the attached figures:

[0059] 1000, vehicles;

[0060] 100. Battery; 200. Controller; 300. Motor;

[0061] 10. Box body; 11. First part; 12. Second part;

[0062] 20. Battery cell; 21. Current collector cap; 211. Electrode terminal; 22. Housing; 23. Electrode assembly; 24. Tab; 25. First plane; 241. First tab; 242. Second tab; 212. Tab connection; 213. Housing connection; 2121. First body; 2122. First connection; 2131. Second connection; 2133. Structural reinforcement; 2134. Third protrusion. Detailed Implementation

[0063] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0064] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0065] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0066] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0067] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0068] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0069] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0070] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0071] Currently, judging from market trends, the application of power batteries is becoming increasingly widespread. Power batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. With the continuous expansion of power battery applications, market demand is also constantly increasing.

[0072] Cylindrical batteries are a common type of battery. In related technologies, a cylindrical battery cell includes a casing, electrode assembly, and end caps. In a cylindrical battery cell, the tab of the negative electrode is usually first connected to the current collector, then the current collector is connected to the end cap, and then the end cap is connected to the casing, ultimately making the casing charged.

[0073] In related technologies, the end cap of a cylindrical battery cell is located outside the negative current collector. Electrical connection is achieved by through welding from the end cap side. However, due to the inherent poor reliability of through welding and the flatness of the end cap material, current through welding is prone to producing poor welding between the current collector and the end cap, resulting in poor electrical connection of the battery cell and affecting the performance and reliability of the battery cell. At the same time, the method of through welding the end cap and current collector from the end cap side may damage the plating on the surface of the end cap and reduce the reliability of the end cap.

[0074] Based on the above considerations, in order to solve the problem of poor welding between the current collector and the end cap, this application proposes a battery cell including a current collector end cap connected to the tabs and the housing. By connecting the tab connection part on the current collector end cap to the first tab and the housing connection part to the housing, the current collector end cap achieves an integrated design of the current collector and the end cap. This allows for a reliable connection between the tab connection part and the housing connection part before the connection step between the tab connection part and the first tab. This not only reduces the number of parts during battery assembly and simplifies the welding process, but also reduces the risk of poor welding and improves the reliability of the battery cell.

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

[0076] This application provides an electrical device that uses a battery as a power source. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

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

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

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

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

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

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

[0083] According to some embodiments of this application, refer to Figure 3 and Figure 4 , Figure 3 This is an exploded structural diagram of the battery cell 20 provided in some embodiments of this application. Figure 4This is a schematic diagram of the structure of a battery cell according to some embodiments of this application. This application provides a battery cell 20, which includes an electrode assembly 23, a housing 22, and a current collector cap 21. The electrode assembly 23 includes a first tab 241; the housing 22 has a receiving cavity and an opening at one end of the receiving cavity, the receiving cavity being used to receive the electrode assembly 23; the current collector cap 21 is connected to the housing 22 to close the opening, and the current collector cap 21 includes a connected tab connection portion 212 and a housing connection portion 213, wherein the tab connection portion 212 is connected to the first tab 241, and the housing connection portion 213 is connected to the housing 22.

[0084] In this embodiment, 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 this embodiment is not limited thereto. The battery cell 20 may be cylindrical, flat, cuboid, or other shapes, and this embodiment is not limited thereto.

[0085] Electrode assembly 23 is the component in the battery cell 20 where the electrochemical reaction occurs. The housing 22 can contain one or more electrode assemblies 23. Electrode assembly 23 is mainly formed by winding or stacking positive and negative electrode sheets, and typically a separator is provided between the positive and negative electrode sheets. The portions of the positive and negative electrode sheets containing active material constitute the main body of electrode assembly 23, while the portions of the positive and negative electrode sheets without active material each constitute tabs 24. The positive and negative tabs can be located together at one end of the main body or at opposite ends of the main body. During the charging and discharging process of the battery cell 20, the positive and negative active materials react with the electrolyte, and the tabs 24 connect to the electrode terminals 211 to form a current loop. In this embodiment, the first tab 241 can be a negative tab.

[0086] The current collector cap 21 is a component that covers the opening of the housing 22 to isolate the housing cavity of the battery cell 20 from the external environment. In any case, the shape of the current collector cap 21 may be adapted to the shape of the housing 22 to fit the housing 22.

[0087] In this embodiment, the current collector end cap 21 includes a connected tab connection portion 212 and a housing connection portion 213. The tab connection portion 212 is connected to the first tab 241 and functions as a current collector plate. The housing connection portion 213 is located on the side of the tab connection portion 212 closer to the housing 22 and is connected to the housing 22, so that the current collector end cap 21 acts as an end cap to close the opening of the housing 22. That is, the current collector end cap 21 combines the functions of a current collector plate and an end cap, and the current collector end cap 21 is an integrated structure of a current collector plate and an end cap. The tab connection portion 212 and the housing connection portion 213 can be integrally formed or manufactured separately and then fixedly connected together. The current collector end cap 21 can connect the tab connection portion 212 to the first tab 241 and the housing connection portion 213 to the housing 22, and the connection method can also be welding, such as laser welding or friction welding.

[0088] The housing 22 is an assembly used to cooperate with the current collector cap 21 to form a receiving cavity for the battery cell 20. The formed receiving cavity can accommodate the electrode assembly 23, electrolyte, and other components. The housing 22 and the current collector cap 21 can be independent components. An opening can be provided on the housing 22, and the current collector cap 21 can close the opening to form the receiving cavity for the battery cell 20. Alternatively, the current collector cap 21 and the housing 22 can be integrated. Specifically, the current collector cap 21 and the housing 22 can form a common connecting surface before other components are inserted into the housing. When it is necessary to encapsulate the interior of the housing 22, the current collector cap 21 closes the housing 22. The housing 22 can be of various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 22 can be determined according to the specific shape and size of the electrode assembly 23. The material of the housing 22 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc., and this embodiment does not limit this.

[0089] In this embodiment, a reliable connection between the tab connection 212 and the housing connection 213 can be achieved before the connection step between the tab connection 212 and the first tab 241. This not only reduces the number of parts during battery assembly and simplifies the welding process, but also reduces the risk of poor welding and improves the reliability of the battery cell 20.

[0090] According to some embodiments of this application, the tab connection portion 212 is welded to the first tab 241 to form a welding area Q, and the projection of the welding area Q on the current collector end cover 21 is offset from the housing connection portion 213.

[0091] like Figure 4As shown, the tab connection portion 212 can be located in the central region of the current collector cap 21, and the housing connection portion 213 can be located in the peripheral region surrounding the tab connection portion 212. In some examples, the tab connection portion 212 and the housing connection portion 213 may have a partially overlapping area along the thickness direction of the current collector cap 21, or they may not overlap but simply be adjacent to each other, but the overlapping area will not extend to the area of ​​the tab connection portion 212 used for welding with the first tab 241. In this way, the housing connection portion 213 can expose the area of ​​the tab connection portion 212 used for welding with the first tab 241, so that it is convenient for the tab connection portion 212 and the first tab 241 to be welded and form a welding area Q during the assembly of the battery cell 20. In some examples, the tab connection portion 212 and the first tab 241 are formed to form the welding area Q by laser welding. For example, the laser is emitted from the outside of the current collector cap 21 (the side away from the electrode assembly) and melts the tab connection portion 212 and the first tab 241 (at least a portion) in sequence to form the welding area Q.

[0092] In this embodiment, the projection of the welding area Q formed by welding the tab connection 212 and the first tab 241 onto the current collector end cover 21 is offset from that of the housing connection 213. This is more conducive to the connection of the current collector end cover 21 to the first tab 241 and the housing 22 respectively, simplifies the manufacturing process of the battery cell 20, and reduces the weight of the current collector end cover 21, which is beneficial to improving the energy density of the battery cell 20.

[0093] According to some embodiments of this application, the elongation at break of the housing connection portion 213 is less than the elongation at break of the tab connection portion 212.

[0094] In this embodiment, the elongation at break is the ratio of the increase in length of the material before fracture to the original length. The specific test method for the elongation at break is as follows: take a tensile specimen with an original length of L0, stretch the tensile specimen on a tensile testing machine until fracture, and the length of the tensile specimen before fracture is Lh. Then the elongation at break of the tensile specimen is Δh=(Lh-L0) / L0×100%. The specific conditions and requirements for the tensile test can be carried out with reference to relevant standards, such as the relevant provisions and requirements in the Chinese National Standard GB / T 228.1—2021 "Metallic materials, tensile testing - Part 1: Test method at room temperature".

[0095] Elongation at break is closely related to the material's composition, structure, and processing. Generally, the higher the elongation at break, the better the material's ductility, allowing it to undergo plastic deformation under external forces, thus reducing stress concentration and improving tensile strength and impact resistance. Secondly, materials with high elongation at break possess better toughness, absorbing energy when subjected to impacts or vibrations, thereby reducing the likelihood of accidents. Furthermore, materials with high elongation at break can also improve product lifespan and reliability.

[0096] In this embodiment, the current collector end cap 21 needs to be connected to the first tab 241 and the housing 22 respectively. Material selection and processing must consider both the welding process requirements and conductivity requirements when welding to the first tab 241, as well as the structural strength requirements of the battery end cap. By rationally selecting material types and / or processing methods based on the performance requirements of the tab connection 212 and the housing connection 213 respectively, the elongation at break of the housing connection 213 can be made greater than that of the tab connection 212. This allows the tab connection 212 to be designed with greater consideration for current flow to the first tab 241, while the housing connection 213 provides support for the overall structural strength of the current collector end cap 21. In some embodiments, the elongation at break of the tab connection 212 and the housing connection 213 are different. Thus, the tab connection 212 on the current collector end cover 21 forms a structurally weakened area relative to the housing connection 213. Once thermal runaway occurs inside the battery cell 20, the solder area between the tab connection 212 and the first tab 241 can be broken as a weak area of ​​the current collector end cover 21, thereby improving the reliability of pressure relief to a certain extent.

[0097] In this embodiment, by setting the elongation at break of the tab connection 212 to be less than that of the housing connection 213, the different connection requirements of the tab connection 212 and the housing connection 213, as well as the overall structural strength requirements of the current collector end cover 21, can be better taken into account. At the same time, the tab connection 212 will break first when the internal pressure of the battery cell 20 is high in order to release pressure, thereby improving the reliability of the battery cell 20.

[0098] According to some embodiments of this application, the ratio S of the elongation at break of the housing connection portion 213 to the elongation at break of the tab connection portion 212 satisfies 1.1≤S≤2.2.

[0099] In this embodiment, both the housing connection portion 213 and the tab connection portion 212 are part of the current collector end cover 21. Therefore, when selecting materials and formulating processing technology, in addition to considering the individual performance requirements of the housing connection portion 213 and the tab connection portion 212, the overall stability and reliability of the current collector end cover 21 constituted by the two must also be considered. Thus, the difference between the elongation at break of the housing connection portion 213 and the elongation at break of the tab connection portion 212 should not be too large; otherwise, the current collector end cover 21 will suffer from insufficient overall reliability due to excessive local performance differences, thereby affecting its service life. Optionally, the ratio S of the elongation at break of the housing 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.

[0100] In this embodiment of the application, by setting the ratio S of the fracture elongation of the housing connection portion 213 to the fracture elongation of the electrode connection portion 212 to satisfy 1.1≤S≤2.2, the stability of the performance and service life of the current collector end cover 21 can be taken into account while meeting the structural strength and connection requirements of the current collector end cover 21.

[0101] According to some embodiments of this application, the elongation at break S1 of the tab connection 212 satisfies 0.2≤S1≤0.3, and the elongation at break S2 of the housing connection 213 satisfies 0.35≤S2≤0.45.

[0102] In this embodiment, a higher elongation at break of the material indicates better ductility, while a lower elongation at break makes the material more prone to fracture under stress. Appropriately selecting the elongation at break of the tab connection 212 and the housing connection 213 allows them to better meet connection requirements and ensures that the tab connection 212 ruptures first when the internal pressure of the battery cell 20 is excessive. Optionally, the elongation at break S1 of the tab connection 212 can be 0.2, 0.24, 0.26, 0.28, 0.3, etc., and the elongation at break S2 of the housing connection 213 can be 0.35, 0.38, 0.4, 0.42, 0.45, etc. In some examples, the tab connection 212 can be made of copper with an elongation at break of 0.24, such as CuT2, and the housing connection 213 can be made of nickel-plated steel with an elongation at break of 0.4.

[0103] In this embodiment of the application, by reasonably selecting the elongation at break of the tab connection 212 and the elongation at break of the housing connection 213, the performance of the current collector end cover 21 can take into account both connection requirements and structural strength requirements.

[0104] According to some embodiments of this application, Figure 5 This is a schematic diagram of the structure of the current collector end cap in some embodiments of this application. Figure 1 ,like Figure 5 As shown, the tab connection portion 212 includes a first body 2121 and a first connecting portion 2122 connected to the first body 2121 and disposed along the outer edge of the first body 2121; the housing connection portion 213 includes a second connecting portion 2131 and a first through hole, the orthographic projection of the first body 2121 on the housing connection portion 213 is located in the first through hole, and the first connecting portion 2122 is welded to the second connecting portion 2131.

[0105] In this embodiment, the tab connection portion 212 includes a first body 2121 for connecting to the first tab 241, and a first connecting portion 2122 disposed on the outer edge of the first body 2121 for connecting to the housing connection portion 213. The first body 2121 and the first connecting portion 2122 can be an integral structure. The shape of the first connecting portion 2122 can be any shape that can connect to the second connecting portion 2131, and the shape of the first connecting portion 2122 can be the same as the shape of the second connecting portion 2131. For example, the shape of the first connecting portion 2122 is a protrusion or a flat plate.

[0106] In this embodiment, the first through hole is defined by the second connecting portion 2131. The first through hole is formed in the central region of the housing connecting portion 213, and the second connecting portion 2131 is disposed 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, square, rectangle, triangle, rhombus, 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 housing connecting portion 213 is located inside 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 current collector end cover 21 and the first electrode tab 241.

[0107] In this embodiment, by providing a first through hole on the housing connection portion 213, the orthographic projection of the first main body 2121 of the electrode connection portion 212 on the housing connection portion 213 is located in the first through hole, and the first connection portion 2122 and the second connection portion 2131 are welded together, the integral molding of the current collector end cover 21 can be better realized, thereby reducing the risk of poor welding between the current collector plate and the end cover caused by the use of through welding, simplifying the manufacturing process and reducing the manufacturing cost.

[0108] According to some embodiments of this application, the first connection portion 2122 includes a first protrusion extending in a direction away from or close to the electrode assembly 23, and the first protrusion abuts against the second connection portion 2131 along a first direction X, where the first direction X is the direction from the center of the current collector cap 21 to the edge of the current collector cap 21.

[0109] In this embodiment, the first protrusion can be distributed on the outer edge of the first body 2121. The extension direction of the first protrusion is from the first body 2121 toward the electrode assembly 23. By abutting the first protrusion with the second connecting portion 2131, the first protrusion can guide the tab connecting portion 212 to complete rapid positioning when connecting with the housing connecting portion 213. This is beneficial for the welding connection of the first connecting portion 2122 and the second connecting portion 2131 in subsequent processes, reduces the precision requirements for operators during assembly, and makes the connection of the tab connecting portion 212 and the housing connecting portion 213 simpler and more convenient. In addition, by setting the first protrusion, the welding position of the tab connecting portion 212 and the housing connecting portion 213 and the connection position with the first tab 241 can be staggered. At the same time, the first protrusion and the housing connecting portion 213 can also be connected by welding methods other than through welding, such as butt welding, thereby providing more reliable connection methods.

[0110] For example, Figure 6 This is a schematic diagram of the structure of the current collection end cover 21 in some embodiments of this application. Figure 2 ,like Figure 6 As shown, the first connecting portion 2122 includes a first protrusion extending away from the electrode assembly 23, and the first protrusion abuts against the second connecting portion 2131 along the first direction X. In this way, the tab connecting portion 212 can be closer to the first tab 241 for welding, achieving a more reliable electrical connection.

[0111] In this embodiment of the application, by providing a first protrusion in the first connecting portion 2122 for connection with the housing connecting portion 213, a simpler and more reliable connection between the tab connecting portion 212 and the housing connecting portion 213 can be achieved.

[0112] According to some embodiments of this application, the second connection portion 2131 includes a second protrusion extending in a direction away from or close to the electrode assembly 23, and the second protrusion abuts against the first connection portion 2122 along a first direction X, where the first direction X is the direction from the center of the current collector cap 21 to the edge of the current collector cap 21.

[0113] In this embodiment, the second protrusion can be distributed on the edge of the housing connection portion 213 near the electrode connection portion 212. The extension direction of the second protrusion is from the housing connection portion 213 toward or away from the electrode assembly 23, facilitating the contact between the second protrusion and the first connection portion 2122. This allows the second protrusion to guide the electrode connection portion 212 to complete rapid positioning when connected to the housing connection portion 213, which is beneficial for the welding connection between the first connection portion 2122 and the second connection portion 2131 in subsequent processes. This reduces the precision requirements for assembly by operators and makes the connection between the electrode connection portion 212 and the housing connection portion 213 simpler and more convenient. The second protrusion and the electrode connection portion 212 can also be connected by welding methods other than through welding, such as butt welding, thereby providing more reliable connection methods.

[0114] Figure 7 This is a schematic diagram of the structure of the current collection end cover 21 in some embodiments of this application. Figure 3 ,like Figure 7 As shown, the second connection portion 2131 includes a second protrusion extending toward the electrode assembly 23, and the second protrusion abuts against the first connection portion 2122 along the first direction X.

[0115] In this embodiment of the application, by providing a second protrusion in the second connection portion 2131, the connection between the tab connection portion 212 and the housing connection portion 213 becomes simpler and more reliable.

[0116] According to some embodiments of this application, the first connecting portion 2122 includes a first protrusion extending away from the electrode assembly 23, and the second connecting portion 2131 includes a second protrusion extending towards the electrode assembly 23. Along a first direction X, the first protrusion and the second protrusion abut against each other, and the first direction X is the direction from the center of the current collector cap 21 to the edge of the current collector cap 21; or, the first connecting portion 2122 includes a second protrusion extending towards the electrode assembly 23, and along a first direction X, the first protrusion and the second protrusion abut against each other, and the first direction X is the direction from the center of the current collector cap 21 to the edge of the current collector cap 21.

[0117] In this embodiment, the first protrusion is distributed on the outer edge of the first body 2121, protruding away from the electrode assembly 23 relative to the first body 2121. The second protrusion is distributed on the edge of the housing connection portion 213 near the tab connection portion 212, protruding towards the electrode assembly 23. The first and second protrusions abut against each other to complete the positioning of the tab connection portion 212 and the housing connection portion 213 before welding, which is beneficial for the welding connection of the first connection portion 2122 and the second connection portion 2131 in subsequent processes. The first and second protrusions can be connected by through welding or by other welding methods, such as butt welding. The protrusion height of the first and second protrusions can be the same or different.

[0118] For example, Figure 8 This is a schematic diagram of the structure of the current collection end cover 21 in some embodiments of this application. Figure 4 ,like Figure 8 As shown, the first connecting portion 2122 includes a first protrusion extending away from the electrode assembly 23, and the second connecting portion 2131 includes a second protrusion extending towards the electrode assembly 23. Along the first direction X, the first protrusion and the second protrusion abut against each other.

[0119] In this embodiment of the application, by providing a first protrusion on the first connecting part 2122 and a second protrusion on the second connecting part 2131, the positioning between the first protrusion and the second protrusion can reduce the precision requirements for the operator when assembling the collector end cover 21, and at the same time facilitate the welding process between the electrode connecting part 212 and the housing connecting part 213, thereby achieving a more reliable connection.

[0120] According to some embodiments of this application, Figure 9 This is a schematic diagram of the structure of the current collection end cover 21 in some embodiments of this application. Figure 5 ,like Figure 9 As shown, 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.

[0121] In this embodiment, the tab connection 212 is flat, the first connection 2122 surrounds the periphery of the first body 2121, and the projected area of ​​the tab connection 212 along its thickness direction is larger than the area of ​​the first through hole on the housing connection 213. Thus, the orthographic projection of the first connection 2122 on the housing connection 213 at least partially overlaps with the second connection 2131. That is, the first connection 2122 at least partially overlaps one side surface of the second connection 2131 so that the first connection 2122 and the second connection 2131 can be connected by welding.

[0122] In this embodiment, by setting the tab connection 212 as a flat plate and making the orthographic projection of the first connection 2122 on the housing connection 213 at least partially overlap with the second connection 2131, the size of the current collector end cover 21 along the thickness direction can be reduced when taking into account the connection and positioning of the tab connection 212 and the housing connection 213, which is beneficial to improving the energy density of the battery.

[0123] According to some embodiments of this application, Figure 10 This is a schematic diagram of the structure of the current collection end cover 21 in some embodiments of this application. Figure 6 ,like Figure 10 As shown, the side of the tab connection portion 212 facing the electrode assembly 23 is flush with the side of the housing connection portion 213 facing the electrode assembly 23.

[0124] In this embodiment, the thickness of the tab connection portion 212 and the thickness of the housing connection portion 213 may be the same or different, but the surface of the current collector end cap 21 facing the electrode assembly 23 is a flat surface.

[0125] In this embodiment, by making the side of the tab connection 212 facing the electrode assembly 23 flush with the side of the housing connection 213 facing the electrode assembly 23, the height of the current collector cover 21 can be reduced while maintaining the strength of the current collector cover 21, thereby increasing the capacity of the housing cavity of the housing 22 and reducing the height of the battery cell 20.

[0126] According to some embodiments of this application, the base metal of the tab connection portion 212 is different from that of the housing connection portion 213.

[0127] In this embodiment, the base metal refers to the main component metal in the material (e.g., alloy or composite material), such as a metallic element with a mass fraction greater than 50%. Different base metal materials will have certain differences in performance. The tab connection 212 needs to be connected to the first tab 241, and the selection of materials and processing need to consider the welding process requirements and conductivity requirements when welding to the first tab 241; the housing connection 213 needs to be connected to the housing 22, and the structural strength requirements as a battery end cap need to be considered. By reasonably selecting the material type according to the performance requirements of the tab connection 212 and the housing connection 213 respectively, the base metals of the tab connection 212 and the housing connection 213 can be different. In this way, the tab connection 212 can meet the reliable connection and overcurrent problem with the first tab 241, while the housing connection 213 can meet the overall structural strength requirements of the current collector end cap 21.

[0128] In this embodiment of the application, by setting the base metal of the tab connection 212 and the housing connection 213 to be different, the different connection requirements of the tab connection 212 and the housing connection 213 as well as the overall strength requirements of the current collector end cover 21 can be better taken into account, thereby improving the performance and reliability of the battery cell 20.

[0129] According to some embodiments of this application, the base metal of the tab connection 212 is copper; the base metal of the housing connection 213 is iron or aluminum.

[0130] In this embodiment, copper possesses excellent electrical conductivity and corrosion resistance, enabling it to rapidly conduct electrons during electrochemical reactions. The base metal of the tab connection 212 is copper, ensuring that the current-carrying capacity of both the tab connection 212 and the first tab 241 is met when the tab connection 212 is connected to the first tab 241. Materials with copper as the base metal include pure copper, nickel-plated copper, iron-plated copper, copper-nickel composite materials, copper-iron composite materials, etc.

[0131] Iron is a common material, with advantages including strength, corrosion resistance, and low cost. Materials with iron as their base metal mainly include various types of steel, such as stainless steel and nickel-plated steel. Aluminum has properties such as hardness, high temperature resistance, and long service life. Materials with aluminum as their base metal include aluminum or aluminum alloys. Materials with iron or aluminum as their base metal have relatively high strength, and their use as the housing connection part 213 can meet the structural strength requirements of the current collector end cover 21.

[0132] In this embodiment, by using copper as the base metal of the tab connection portion 212 and iron or aluminum as the base metal of the housing connection portion 213, the current carrying capacity and structural strength of the current collector end cover 21 can be improved, thereby increasing the reliability of the battery cell 20.

[0133] According to some embodiments of this application, the base metal of the tab connection portion 212 and the housing connection portion 213 is the same.

[0134] In this embodiment, the fact that the base metal of the tab connection portion 212 and the housing connection portion 213 of the current collector end cover 21 is the same means that their materials are similar or even identical. This implies that when manufacturing the current collector end cover 21, the tab connection portion 212 and the housing connection portion 213 can be integrally formed from the same material. For example, the current collector end cover 21 can be manufactured by stamping or other methods. The current collector end cover 21 simultaneously functions as an end cover and a current collector plate, simplifying its structure, thereby reducing its manufacturing process and cost. In other examples, the base metal of the tab connection portion 212 and the housing connection portion 213 is the same, but different processing techniques, such as heat treatment, can result in slight differences in their performance, thus meeting their different performance requirements.

[0135] In this embodiment, the base metal of the tab connection 212 and the housing connection 213 is the same, which simplifies the preparation of the current collector end cap 21 and reduces the risk of unreliable connection between the tab connection 212 and the housing connection 213.

[0136] According to some embodiments of this application, the base metal of the tab connection portion 212 and the housing connection portion 213 is copper.

[0137] In this embodiment, copper has good electrical conductivity and can play a role in rapidly conducting electrons during electrochemical reactions. Copper also has strong corrosion resistance. It is understood that the fact that the base metal of the tab connection 212 and the housing connection 213 is copper does not mean that the two materials are completely identical. Different elements can be doped to form different alloys or composite materials, resulting in different properties. In some examples, the tab connection 212 can be copper, and the housing connection 213 can be a copper alloy or copper composite material, such as nickel-plated copper.

[0138] In this embodiment, copper is selected as the base metal for the tab connection portion 212 and the housing connection portion 213, which can improve the current carrying capacity and corrosion resistance of the current collector end cover 21 and improve the reliability of the battery cell 20.

[0139] According to some embodiments of this application, the maximum thickness of the tab connection portion 212 is d1, the minimum thickness of the housing connection portion 213 is d2, and d1≤d2 is satisfied.

[0140] In the embodiments of this application, due to factors such as manufacturing process and materials, the electrode connection portion 212 and the housing connection portion 213 may have uneven thickness. Figure 11 This is a schematic diagram of the structure of the current collection end cover 21 in some embodiments of this application. Figure 7 ,like Figure 11 As shown, the second direction Y is the same as the thickness direction of the current collector end cap 21. The maximum thickness d1 is the maximum dimension of the tab connection 212 along the second direction Y, and the minimum thickness d2 is the minimum dimension of the housing connection 213 along the second direction Y. d1≤d2 means that the thickness of the housing connection 213 is greater than the thickness of the tab connection 212.

[0141] In this embodiment, the greater the thickness of the component, the greater its bending strength. The maximum thickness d1 of the tab connection 212 is less than or equal to the minimum thickness d2 of the housing connection 213. This is equivalent to increasing the thickness of the housing connection 213 to enhance the overall strength and deformation resistance of the current collector end cover 21. At the same time, the smaller thickness of the tab connection 212 is beneficial to reducing the internal resistance and the weight of the current collector end cover 21, thereby improving the performance of the battery cell 20.

[0142] According to some embodiments of this application, the maximum thickness of the tab connection portion 212 is d1, the minimum thickness of the housing connection portion 213 is d2, and the following condition is met: 0.5≤d1 / d2≤1.

[0143] In this embodiment, if the ratio of the maximum thickness d1 of the tab connection portion 212 to the minimum thickness d2 of the housing connection portion 213 is too small (i.e., the maximum thickness d1 of the tab connection portion 212 is too thin compared to the minimum thickness d2 of the housing connection portion 213), the overall structural strength of the current collector cover 21 will be weakened. After electrical connection, gas generation in the battery cell 20 will cause the current collector cover 21 to bulge or even deform. Conversely, if the ratio is too large, it will lead to an unnecessary increase in weight, which is not conducive to improving the battery energy density.

[0144] Optionally, d1 / d2 can be 0.5, 0.6, 0.7, 0.8, 0.9 or 1, etc.

[0145] In this embodiment, by controlling the ratio of the thickness d1 of the tab connection portion 212 to the thickness d2 of the housing connection portion 213 within a suitable range, the structural strength of the current collector end cover 21 and the energy density of the battery cell 20 can be balanced, thereby improving the performance of the battery cell 20.

[0146] According to some embodiments of this application, the ratio α of the projected area of ​​the tab connection 212 on the first plane 25 to the projected area of ​​the current collector 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 collector end cover 21.

[0147] In this embodiment, the current collector end cap 21 has a generally flat plate structure, and the first plane 25 is a plane perpendicular to the thickness direction of the current collector end cap 21, such as... Figure 11As shown, 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 collector end cap 21.

[0148] The projected area of ​​the tab connection 212 on the first plane 25 is A1, and the projected area of ​​the current collector cover 21 on the first plane 25 is A2. The ratio 'a' between the two satisfies a = A1 / A2. The larger 'a' is, the larger the area proportion of the tab connection 212 in the current collector cover 21. Since the tab connection 212 needs to consider the reliability and current carrying capacity of its electrical connection with the first tab 241, an excessively large 'a' will negatively affect the overall strength of the current collector cover 21, while an excessively small 'a' will also adversely affect the reliability and current carrying capacity of its connection with the first tab 241.

[0149] Optionally, the ratio α of the projected area of ​​the tab connection 212 on the first plane 25 to the projected area of ​​the current collector end cover 21 on the first plane 25 can be 0.1, 0.3, 0.5, 0.7 or 0.95, etc.

[0150] In this embodiment of the application, limiting the ratio 'a' of the projected area of ​​the tab connection 212 on the first plane 25 to the projected area of ​​the current collector end cover 21 on the first plane 25 to a suitable range can better balance the connection reliability and current carrying capacity between the current collector end cover 21 and the first tab 241, as well as the overall structural strength, thereby improving the reliability of the current collector end cover 21.

[0151] According to some embodiments of this application, the ratio α of the projected area of ​​the tab connection 212 on the first plane 25 to the projected area of ​​the current collector end cover 21 on the first plane 25 satisfies: 0.4≤a≤0.6.

[0152] Optionally, the ratio α of the projected area of ​​the tab connection 212 on the first plane 25 to the projected area of ​​the current collector end cover 21 on the first plane 25 can be 0.4, 0.5 or 0.6, etc.

[0153] In this embodiment of the application, by setting the area ratio α of the tab connection portion 212 to the current collector end cover 21 between 0.4 and 0.6, the current collector end cover 21 has more uniform capabilities in terms of current carrying capacity, connection reliability, and structural strength.

[0154] According to some embodiments of this application, the current collector end cover 21 further includes a structural reinforcement portion 2133, which is located at the end of the housing connection portion 213 near the housing 22. Along the thickness direction of the current collector end cover 21, the maximum dimension d3 of the structural reinforcement portion 2133 is greater than the maximum thickness d4 of the housing connection portion 213.

[0155] In this embodiment, the structural reinforcement 2133 can be integrally formed with the housing connection 213, and even integrally formed with the electrode connection 212, and different thicknesses or structural forms can be formed later through processing. Alternatively, the structural reinforcement 2133 can be manufactured separately and connected to the housing connection 213 to obtain a complete current collector end cap 21.

[0156] The structural reinforcement 2133 can be achieved by thickening a local portion of the current collecting end cap 21. For example, Figure 12 This is a schematic diagram of the structure of the current collection end cover 21 in some embodiments of this application. Figure 8 ,like Figure 12 As shown, a structural reinforcement 2133 is provided around the housing connection portion 213 of the collector end cover 21. Along the second direction Y, which is the same as the thickness direction of the collector end cover 21, the maximum dimension d3 of the structural reinforcement 2133 is greater than the maximum thickness d4 of the housing connection portion 213.

[0157] Figure 13 This is a schematic diagram of the structure of the current collection end cover 21 in some embodiments of this application. Figure 9 .like Figure 13 As shown, it can be understood that the maximum dimension d3 of the structural reinforcement 2133 can be a local dimension, allowing the structural reinforcement 2133 to also have a dimension along the second direction Y that is smaller than the maximum thickness d4 of the shell connection 213. The structural reinforcement 2133 can be one or more folds stamped on a plate-like structure, wherein the maximum dimension d3 along the second direction Y is greater than the maximum thickness d4 of the shell connection 213.

[0158] In this embodiment of the application, by adding a structural reinforcement 2133 to the housing connection 213, the overall strength of the current collector end cover 21 can be increased, and the deformation resistance of the current collector end cover 21 can be improved. This is not only beneficial for installation and welding positioning during connection, but also beneficial for improving the structural reliability of the battery cell 20.

[0159] According to some embodiments of this application, the structural reinforcement 2133 includes at least one third protrusion 2134, which protrudes relative to the housing connection 213 in a direction away from the electrode assembly 23 or in a direction closer to the electrode assembly 23 relative to the housing connection 213.

[0160] In this embodiment, the structural reinforcement 2133 can also be implemented by providing a protrusion on the current collection end cover 21.

[0161] For example, such as Figure 13As shown, the structural reinforcement 2133 may include a third protrusion 2134. The third protrusion 2134 protrudes away from the electrode assembly 23 relative to the housing connection 213. The number of third protrusions 2134 may be one or more, and the shape of the third protrusion 2134 may be arbitrary; this embodiment does not impose any limitations. In other examples, the third protrusion 2134 may also protrude closer to the electrode assembly 23.

[0162] In this embodiment of the application, the structural reinforcement 2133 is formed by setting a third protrusion 2134, which simplifies the structural form of the structural reinforcement 2133, facilitates processing and manufacturing, and reduces unnecessary weight increase while providing strength support.

[0163] According to some embodiments of this application, the projection of the third protrusion 2134 onto the first plane 25 is annular, wherein the first plane 25 is a plane perpendicular to the thickness direction of the collector end cap 21.

[0164] In some examples, Figure 14 for Figure 13 Top view, such as Figure 14 As shown, the current 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 housing connection 213 to form an annular reinforcing part, which can further increase the structural strength of the current collecting end cover 21.

[0165] According to some embodiments of this application, there are multiple third protrusions 2134, which are spaced apart along a first direction X, where 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.

[0166] In this embodiment, the distance between two adjacent third protrusions 2134 can be the same or different, and this embodiment does not impose any restrictions.

[0167] In this embodiment, by providing multiple third protrusions 2134 along the direction X from the center of the current collector end cover 21 to the edge of the current collector end cover 21, compared with the increase in overall thickness, it can more effectively balance the strength requirements and energy density requirements, and improve the overall performance of the battery cell 20.

[0168] According to some embodiments of this application, such as Figure 11 As shown, the ratio of the projected area A1 of the tab connection 212 on the first plane 25 to the projected area A2 of the collector end cover 21 on the first plane 25 is a, and the minimum thickness of the tab connection 212 along the thickness direction of the collector 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 collector end cover 21.

[0169] In this embodiment, the solder area connecting the tab connection 212 and the first tab 241 can act as a relatively weak structural area, potentially rupturing when the internal pressure of the battery cell 20 reaches a certain preset threshold, thus functioning as an explosion-proof valve. Simultaneously, due to manufacturing process variations, the thickness of the tab connection 212 varies along the second direction Y, which is the same as the thickness direction of the current collector cap 21.

[0170] 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 collector 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 collector cap 21, both affect the strength of the area where the tab connection 212 is located in the battery cell 20 as an explosion-proof valve. Specifically, if the minimum thickness d0 of the tab connection 212 along the thickness direction of the current collector 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 collector cap 21 on the first plane 25 is too small, it will lead to excessively high explosion-proof valve strength, making it difficult to open the valve in time under severe conditions such as thermal runaway or excessive internal gas pressure in the battery cell 20, resulting in the shell 22 rupturing. If the minimum thickness d0 of the tab connection 212 along the thickness direction of the current collector cap 21 is too small, 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 collector cap 21 on the first plane 25 is too large, it will lead to insufficient strength of the explosion-proof valve. During the production and use of the battery cell 20, the explosion-proof valve may open uncontrollably due to other external forces, resulting in leakage of the battery cell 20, abnormal electrical connection, etc. Optionally, the value of d0 / a can be 0.05, 0.1, 1, 5, 10, 20, or 40, etc.

[0171] In some embodiments, the current collector cap 21 further includes at least one pressure relief portion configured to release pressure when the pressure within the receiving cavity of the battery cell 20 is greater than or equal to a preset threshold. For example, Figure 15 This is a top view of the current collector end cap of some other embodiments of this application, such as... Figure 15 As shown, the pressure relief section can be a groove, which is located on at least one of the first surface of the current collector end cover 21 facing the electrode assembly 23 and the second surface facing away from the electrode assembly 23, and the thickness of the groove is less than the thickness around the groove.

[0172] In this embodiment, by setting 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 collector end cover 21 on the first plane 25 to the minimum thickness d0 of the tab connection 212 along the thickness direction of the current collector end cover 21 between 0.05 and 40, the area where the tab connection 212 is located can have a suitable valve opening strength as an explosion-proof valve, thereby achieving more stable and reliable valve opening and pressure relief, and improving the reliability of the battery cell 20.

[0173] According to some embodiments of this application, the value of d0 / a satisfies: 0.8≤d0 / a≤1.6.

[0174] Optionally, the value of d0 / a can be 0.8, 1.0, 1.2, 1.5 or 1.6, etc.

[0175] In this embodiment, by setting 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 collector end cover 21 on the first plane 25 to the minimum thickness d0 of the tab connection 212 along the thickness direction of the current collector end cover 21 between 0.8 and 1.6, the opening strength of the explosion-proof valve of the battery cell 20 can be made within a more suitable range, thereby improving the reliability of the battery cell 20.

[0176] According to some embodiments of this application, Figure 16 This is a schematic diagram of the structure of another battery cell according to some embodiments of this application, such as... Figure 16 As shown, the housing 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 tab 242 near the end wall. The second tab 242 has a different polarity from the first tab 241. The battery cell 20 also includes an electrode terminal 211, which passes through the second through hole and is electrically connected to the second tab 242.

[0177] In this embodiment, the electrode terminal 211 is an output component for outputting electrical energy from the battery cell 20, such as a terminal post, and the number of electrode terminals 211 can be one. For example, the first electrode tab 241 is the negative electrode tab, and the second electrode tab 242 is the positive electrode tab.

[0178] In this embodiment, the electrode terminal 211 passes through the second through hole and is electrically connected to the second tab 242. The current collector end cover 21 is electrically connected to the first tab 241. The current collector end cover 21 realizes the integrated design of the current collector plate and the end cover. It can realize a reliable electrical connection between the current collector plate and the end cover before the battery is assembled, reduce the risk of poor soldering during battery cell assembly, and thus improve the reliability of the battery cell 20.

[0179] Figure 17 This is a flowchart illustrating a method for manufacturing a single battery cell according to some embodiments of this application. For example... Figure 17 As shown, the manufacturing method of a single battery cell includes:

[0180] Step S1710: Provide an electrode assembly, a housing, and a current collector cap. The electrode assembly includes a first tab, the housing has a receiving cavity and an opening at one end of the receiving cavity, and the current collector cap includes a connected tab connection portion and a housing connection portion.

[0181] Step S1720: Place the electrode assembly into the receiving cavity of the housing.

[0182] Step S1730: Weld the tab connection of the current collector end cap to the first tab of the electrode assembly.

[0183] Step S1740: Weld the housing connection part of the current collector end cover to the housing.

[0184] In this application embodiment, the battery cell 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 this application embodiment is not limited thereto. The battery cell may be cylindrical, flat, cuboid, or other shapes, etc., and this application embodiment is not limited thereto.

[0185] Electrode assemblies are components within a single battery cell where electrochemical reactions occur. The housing can contain one or more electrode assemblies. A current collector cap is a component that closes onto the opening of the housing to isolate the battery cell's containment from the external environment. The shape of the current collector cap may, without limitation, be adapted to the shape of the housing to fit the housing.

[0186] In this embodiment, the current collector end cap includes a connected tab connection portion and a housing connection portion. The tab connection portion is connected to the first tab and functions as a current collector plate. The housing connection portion is located on the side of the tab connection portion closer to the housing and is connected to the housing, so that the current collector end cap acts as an end cap to close the opening of the housing. In other words, the current collector end cap combines the functions of a current collector plate and an end cap, and is an integrated structure of a current collector plate and an end cap. The tab connection portion and the housing connection portion can be integrally formed or manufactured separately and then fixedly connected together.

[0187] In this embodiment of the application, the electrode assembly is placed in the receiving cavity of the housing. The current collector end cover can first weld the electrode tab connection part to the first electrode tab, and then weld the housing connection part to the housing, such as laser welding or friction welding.

[0188] In this embodiment of the application, during the assembly process of the battery cell, the current collector end cap, as a separate incoming part, achieves a reliable connection between the electrode connection part and the housing connection part before welding with the first electrode and the housing. This simplifies the welding process during battery cell assembly, reduces the risk of incomplete welding, and improves the reliability of the battery cell.

[0189] According to some embodiments of this application, the aforementioned step S1730 includes: placing the current collector end cap at the opening of the housing so that the electrode connection portion abuts against the first electrode tab; emitting a laser from the side of the current collector end cap away from the electrode assembly and penetrating the electrode connection portion so that the electrode connection portion is welded to the first electrode tab.

[0190] In this embodiment, since the electrode assembly is located inside the housing cavity, and the corresponding first electrode tab is also located inside the housing, when the current collector cap is placed at the opening of the housing, the electrode tab connection can abut against the first electrode tab. Laser welding can be used to weld the electrode tab connection to the first electrode tab. Specifically, the electrode tab connection and the first electrode tab are heated by laser radiation. The surface heat diffuses inward 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 electrode tab connection and melts the first electrode tab, thereby welding the electrode tab connection to the first electrode tab.

[0191] In this embodiment, the current collector end cap is arranged at the opening of the housing so that the electrode connection part abuts against the first electrode. The laser is emitted from the side of the current collector end cap away from the electrode assembly and penetrates the electrode connection part so that the electrode connection part is welded to the first electrode, which further simplifies the welding process of the battery cell.

[0192] This application provides a battery 100, which includes the battery cell 20 in the above embodiments.

[0193] By using the battery cell 20 in the embodiments of this application, the probability of poor soldering between the current collector and the end cover caused by the use of through soldering can be reduced, thereby improving the safety and reliability of the battery cell 20.

[0194] This application provides an electrical device, which includes the battery 100 in the above embodiment, and the battery 100 is used to provide electrical energy.

[0195] The technical solution of this application will be further described below through a specific embodiment, such as... Figures 1 to 15 As shown,

[0196] The battery cell 20 includes an electrode assembly 23, a housing 22, and a current collector cap 21. The electrode assembly 23 includes a first tab 241; the housing 22 has a receiving cavity and an opening at one end of the receiving cavity, the receiving cavity being used to house the electrode assembly 23; the current collector cap 21 is connected to the housing 22 to close the opening, and the current collector cap 21 includes a connected tab connection portion 212 and a housing connection portion 213, wherein the tab connection portion 212 is connected to the first tab 241, and the housing connection portion 213 is connected to the housing 22. The tab connection portion 212 is welded to the first tab 241 to form a welding area Q, and the projection of the welding area Q onto the current collector cap 21 is offset from that of the housing connection portion 213.

[0197] The housing 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 tab 242 near the end wall. The second tab 242 has a different polarity from the first tab 241. The battery cell 20 also includes an electrode terminal 211, which passes through the second through hole and is electrically connected to the second tab 242.

[0198] The elongation at break of the tab connection 212 is less than that of the shell connection 213. The ratio S of the elongation at break of the shell connection 213 to that of the tab connection 212 satisfies 1.1≤S≤2.2. The elongation at break of the tab connection 212 S1 satisfies 0.2≤S1≤0.3. The elongation at break of the shell connection 213 S2 satisfies 0.35≤S2≤0.45.

[0199] The tab connection portion 212 includes a first body 2121 and a first connecting portion 2122 connected to the first body 2121 and disposed along the outer edge of the first body 2121; the housing connection portion 213 includes a second connecting portion 2131 and a first through hole, the orthographic projection of the first body 2121 on the housing connection portion 213 is located in the first through hole, and the first connecting portion 2122 is welded to the second connecting portion 2131.

[0200] In some embodiments, the first connection portion 2122 includes a first protrusion extending in a direction away from or close to the electrode assembly 23, and the first protrusion abuts against the second connection portion 2131 along a first direction X, where the first direction X is the direction from the center of the current collector cap 21 to the edge of the current collector cap 21.

[0201] In some embodiments, the second connection portion 2131 includes a second protrusion extending in a direction away from or close to the electrode assembly 23, and the second protrusion abuts against the first connection portion 2122 along a first direction X, where the first direction X is the direction from the center of the current collector cap 21 to the edge of the current collector cap 21.

[0202] In some embodiments, the first connecting portion 2122 includes a first protrusion extending away from the electrode assembly 23, and the second connecting portion 2131 includes a second protrusion extending towards the electrode assembly 23. The first protrusion abuts against the second protrusion along a first direction X, where the first direction X is the direction from the center of the current collector cap 21 to the edge of the current collector cap 21; or, the first connecting portion 2122 includes a second protrusion extending towards the electrode assembly 23. The first protrusion abuts against the second protrusion along a first direction X, where the first direction X is the direction from the center of the current collector cap 21 to the edge of the current collector cap 21.

[0203] In some embodiments, the tab connection portion 212 is flat, and the orthographic projection of the first connection portion 2122 onto 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 side of the housing connection portion 213 facing the electrode assembly 23.

[0204] The base metal of the tab connection 212 and the housing connection 213 are different. For example, the base metal of the tab connection 212 is copper, and the base metal of the housing connection 213 is iron or aluminum; or the base metal of the tab connection 212 and the housing connection 213 are the same. For example, the base metal of the tab connection 212 and the housing connection 213 is copper.

[0205] The maximum thickness of the tab connection 212 is d1, and the minimum thickness of the housing connection 213 is d2, and d1≤d2 and 0.5≤d1 / d2≤1 are satisfied.

[0206] The ratio α of the projected area of ​​the tab connection 212 on the first plane 25 to the projected area of ​​the current collector end cover 21 on the first plane 25 satisfies: 0.4≤a≤0.6, where the first plane 25 is a plane perpendicular to the thickness direction of the current collector end cover 21.

[0207] The current collector end cap 21 also includes a structural reinforcement portion 2133, which is located at the end of the housing connection portion 213 near the housing 22. Along the thickness direction of the current collector end cap 21, the maximum dimension d3 of the structural reinforcement portion 2133 is greater than the maximum thickness d4 of the housing connection portion 213. The structural reinforcement portion 2133 includes at least one third protrusion 2134, which protrudes relative to the housing connection portion 213 in a direction away from the electrode assembly 23 or in a direction relative to the housing connection portion 213 in a direction closer to the electrode assembly 23. The projection of the third protrusion 2134 on the first plane 25 is annular. There are multiple third protrusions 2134, which are spaced apart along a first direction X, where the first direction X is the direction from the center of the current collector end cap 21 to the edge of the current collector end cap 21.

[0208] The ratio of the projected area of ​​the tab connection 212 on the first plane 25 to the projected area of ​​the collector end cover 21 on the first plane 25 is 'a'. The minimum thickness of the tab connection 212 along the thickness direction of the collector end cover 21 is 'd0', where 0.05 ≤ d0 / a ≤ 40. The first plane 25 is a plane perpendicular to the thickness direction of the collector end cover 21. The value of d0 / a satisfies: 0.8 ≤ d0 / a ≤ 1.6.

[0209] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized in that, include: Electrode assembly, including a first electrode tab; The housing has a receiving cavity and an opening at one end of the receiving cavity, the receiving cavity being used to receive the electrode assembly; A current collector end cap is connected to the housing to close the opening. The current collector end cap includes a connected tab connection portion and a housing connection portion. The tab connection portion is connected to the first tab, and the housing connection portion is connected to the housing. The current collecting end cover also includes a structural reinforcement, which is located at one end of the housing connection near the housing. Along the thickness direction of the current collecting end cover, the maximum dimension of the structural reinforcement is greater than the maximum thickness of the housing connection. The structural reinforcement includes at least one third protrusion that protrudes away from the electrode assembly relative to the housing connection or protrudes closer to the electrode assembly relative to the housing connection.

2. The battery cell according to claim 1, characterized in that, The electrode connecting part is welded to the first electrode to form a welding area, and the projection of the welding area on the current collector end cover is offset from the housing connecting part.

3. The battery cell according to claim 2, characterized in that, The elongation at break of the tab connection is less than that of the shell connection.

4. The battery cell according to claim 3, characterized in that, The ratio S of the elongation at break of the housing connection to the elongation at break of the tab connection satisfies 1.1≤S≤2.

2.

5. The battery cell according to claim 3, characterized in that, The elongation at break of the tab connection part S1 satisfies 0.2≤S1≤0.3, and the elongation at break of the shell connection part S2 satisfies 0.35≤S2≤0.

45.

6. The battery cell according to claim 1, characterized in that, The electrode connection portion includes a first main body and a first connection portion connected to the first main body and disposed along the outer edge of the first main body; The housing connection includes a second connection and a first through hole. The orthographic projection of the first body on the housing connection is located in the first through hole. The first connection is welded to the second connection.

7. The battery cell according to claim 6, characterized in that, The first connecting portion includes a first protrusion extending in a direction away from or towards the electrode assembly, and the first protrusion abuts against the second connecting portion along a first direction, the first direction being the direction from the center of the current collector cap to the edge of the current collector cap.

8. The battery cell according to claim 6, characterized in that, The second connection portion includes a second protrusion extending in a direction away from or towards the electrode assembly. Along a first direction, the second protrusion abuts against the first connection portion, the first direction being the direction from the center of the current collector cap to the edge of the current collector cap.

9. The battery cell according to claim 6, characterized in that, The first connecting portion includes a first protrusion extending away from the electrode assembly, and the second connecting portion includes a second protrusion extending towards the electrode assembly. Along a first direction, the first protrusion abuts against the second protrusion, and the first direction is the direction from the center of the current collector cap to the edge of the current collector cap; or, the first connecting portion includes a second protrusion extending towards the electrode assembly, and along a first direction, the first protrusion abuts against the second protrusion, and the first direction is the direction from the center of the current collector cap to the edge of the current collector cap.

10. The battery cell according to claim 6, characterized in that, The tab connection is flat, and the orthographic projection of the first connection on the housing connection overlaps at least partially with the second connection.

11. The battery cell according to claim 6, characterized in that, The side of the tab connection facing the electrode assembly is flush with the side of the housing connection facing the electrode assembly.

12. The battery cell according to any one of claims 1-11, characterized in that, The base metal of the tab connection part is different from that of the housing connection part.

13. The battery cell according to claim 12, characterized in that, The base metal of the tab connection is copper; the base metal of the housing connection is iron or aluminum.

14. The battery cell according to any one of claims 1-11, characterized in that, The base metal of the tab connection part is the same as that of the housing connection part.

15. The battery cell according to claim 14, characterized in that, The base metal of the electrode connection part and the housing connection part is copper.

16. The battery cell according to any one of claims 1-11, characterized in that, The maximum thickness of the tab connection is d1, the minimum thickness of the housing connection is d2, and d1≤d2 is satisfied.

17. The battery cell according to claim 16, characterized in that, The maximum thickness of the tab connection is d1, and the minimum thickness of the housing connection is d2, and both satisfy: 0.5 ≤ d1 d2≤1.

18. The battery cell according to any one of claims 1-11, characterized in that, The ratio 'a' of the projected area of ​​the tab connection portion on the first plane to the projected area of ​​the current collector end cover on the first plane satisfies: 0.1≤a≤0.95, where the first plane is a plane perpendicular to the thickness direction of the current collector end cover.

19. The battery cell according to claim 18, characterized in that, The ratio 'a' of the projected area of ​​the electrode connection part on the first plane to the projected area of ​​the current collecting end cover on the first plane satisfies: 0.4≤a≤0.

6.

20. The battery cell according to claim 1, characterized in that, The projection of the third protrusion onto the first plane is annular, wherein the first plane is a plane perpendicular to the thickness direction of the collector end cap.

21. The battery cell according to claim 1, characterized in that, The number of the third protrusions is multiple, and they are spaced apart along a first direction, which is the direction from the center of the collector end cover to the edge of the collector end cover.

22. The battery cell according to any one of claims 1-11, characterized in that, The ratio of the projected area of ​​the tab connection on the first plane to the projected area of ​​the collector end cover on the first plane is a, and the minimum thickness of the tab connection along the thickness direction of the collector end cover is d0, wherein 0.05≤d0 / a≤40, and wherein the first plane is a plane perpendicular to the thickness direction of the collector end cover.

23. The battery cell according to claim 22, characterized in that, The value of d0 / a satisfies: 0.8≤d0 / a≤1.

6.

24. The battery cell according to any one of claims 1-11, characterized in that, The housing includes an end wall away from the opening, and the end wall is provided with a second through hole. The electrode assembly further includes a second tab near the end wall, the second tab having a different polarity than the first tab. The battery cell also includes an electrode terminal, which passes through the second through hole and is electrically connected to the second tab.

25. A battery, characterized in that, Includes the battery cell as described in any one of claims 1-24.

26. An electrical appliance, characterized in that, The electrical device includes the battery as described in claim 25, the battery being used to provide electrical energy.

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