Battery cell, battery, electrical equipment, and manufacturing method and equipment of battery cell

Abstract

Embodiments of the present application provide a battery cell, a battery, an electrical device, and a manufacturing method and device for the battery cell, belonging to the technical field of batteries. The battery cell includes a housing, an electrode assembly, an end cap, and a current collector member. The housing has an opening, the electrode assembly has a tab, the electrode assembly is configured to be received in the housing, the end cap is configured to cover the opening, and the current collector member is configured to connect the end cap and the tab to achieve electrical connection between the end cap and the tab. The current collector member is welded to the tab to form a first welding portion and a second welding portion, and the current collector member is welded to the end cap to form a third welding portion. The first welding portion is located on the inner peripheral side of the third welding portion, and the second welding portion is located on the outer peripheral side of the third welding portion. The battery cell with this structure can equalize the movement paths of electrons in the inner ring part and the outer ring part of the electrode assembly, reduce the internal resistance of the battery cell, and effectively improve the service life of the battery cell.

Description

Technical Field

[0001] The present application relates to the technical field of batteries, and more particularly, to a battery cell, a battery, an electrical device, and a manufacturing method and device for the battery cell. Background Art

[0002] Energy conservation and emission reduction are the keys to the sustainable development of the automotive industry. Electric vehicles have become an important part of the sustainable development of the automotive industry due to their advantages of energy conservation and environmental protection. For electric vehicles, battery technology is an important factor related to their development.

[0003] In battery technology, it is necessary to consider both the safety of the battery cell and the service life of the battery cell. Therefore, how to improve the service life of the battery cell is an urgent problem to be solved in battery technology. Summary of the Invention

[0004] Embodiments of the present application provide a battery cell, a battery, an electrical device, and a manufacturing method and device for the battery cell, which can effectively improve the service life of the battery cell.

[0005] In a first aspect, an embodiment of the present application provides a battery cell, including: a housing having an opening; an electrode assembly having a tab, the electrode assembly being configured to be received in the housing; an end cap for covering the opening; a current collector member for connecting the end cap and the tab to achieve electrical connection between the end cap and the tab; wherein, the current collector member is welded to the tab to form a first welding portion and a second welding portion, the current collector member is welded to the end cap to form a third welding portion, the first welding portion is located on the inner peripheral side of the third welding portion, and the second welding portion is located on the outer peripheral side of the third welding portion.

[0006] In the above technical solution, the current collector member is welded to the tab to form a first welding portion and a second welding portion, the current collector member is welded to the end cap to form a third welding portion, and the first welding portion and the second welding portion are respectively located on the inner peripheral side and the outer peripheral side of the third welding portion, so that the electrons in the inner ring portion of the electrode assembly can move along the path of the tab, the first welding portion, the current collector member, the third welding portion, and the end cap, and the electrons in the outer ring portion of the electrode assembly can move along the path of the tab, the second welding portion, the current collector member, the third welding portion, and the end cap, equalizing the movement paths of the electrons in the inner ring portion and the outer ring portion of the electrode assembly, reducing the internal resistance of the battery cell, and effectively improving the life of the battery cell.

[0007] In some embodiments, the current collector member includes: a body portion for abutting and welding with the tab to form the first welding portion and the second welding portion; a convex portion protruding from the outer surface of the body portion in a direction facing the end cap, the convex portion being used for abutting and welding with the end cap to form the third welding portion.

[0008] In the above technical solution, the body part is the part where the current collector member is welded to the tab, and the convex part is the part where the current collector member is welded to the end cap. The convex part of the current collector member protrudes from the outer surface of the body part in the direction facing the end cap. The contact between the convex part and the end cap can ensure good contact, which is convenient for welding the end cap and the current collector member.

[0009] In some embodiments, the body part includes: a first connecting part, which is connected to the convex part and located on the inner circumferential side of the convex part. The first connecting part is used to abut against and weld with the tab to form a first welding part; a second connecting part, which is connected to the convex part and located on the outer circumferential side of the convex part. The second connecting part is used to abut against and weld with the tab to form the second welding part.

[0010] In the above technical solution, the first connecting part of the body part is located on the inner circumferential side of the convex part, and the second connecting part of the body part is located on the outer circumferential side of the convex part. The first connecting part and the second connecting part are separated by the convex part, so that the entire current collector member forms three welding areas with obvious boundaries. The three welding areas are the areas corresponding to the first connecting part, the convex part, and the second connecting part of the current collector member respectively. By welding the first connecting part with the tab, the second connecting part with the tab, and the end cap with the convex part, it can be ensured that the first welding part and the second welding part are located on the inner circumferential side and the outer circumferential side of the third welding part respectively, which can improve the welding efficiency of the current collector member with the tab and the welding efficiency of the end cap with the current collector member, and improve the productivity.

[0011] In some embodiments, the outer surface of the first connecting part and the inner circumferential surface of the convex part jointly define a first avoiding part, and the first avoiding part is used to avoid the first welding part; the outer surface of the second connecting part and the outer circumferential surface of the convex part jointly define a second avoiding part, and the second avoiding part is used to avoid the second welding part.

[0012] In the above technical solution, the outer surface of the first connecting part and the inner circumferential surface of the convex part jointly define a first avoiding part for avoiding the first welding part, which ensures good contact between the convex part and the end cap. The outer surface of the second connecting part and the outer circumferential surface of the convex part jointly define a second avoiding part for avoiding the second welding part, which ensures good contact between the convex part and the end cap.

[0013] In some embodiments, a concave part is formed at the position of the current collector member corresponding to the convex part, and the concave part is recessed from the inner surface of the body part in the direction facing the end cap; the convex part has a first abutting surface for abutting against the end cap, and the convex part has a third connecting part located between the first abutting surface and the bottom surface of the concave part. The third connecting part is used to weld with the end cap to form the third welding part.

[0014] In the above technical solution, the provision of the concave portion of the current collecting member can, on the one hand, reduce the weight of the current collecting member and save materials, and on the other hand, the concave portion can avoid the third welding portion, reducing the impact on the position where the current collecting member and the tab have been welded when welding the end cap and the convex portion.

[0015] In some embodiments, the concave portion is an annular groove.

[0016] In the above technical solution, the concave portion is an annular groove, which has a simple structure and is easy to form and manufacture. When welding the end cap and the current collecting member, the end cap and the convex portion can be welded along the circumference of the concave portion, improving the firmness after welding the end cap and the current collecting member.

[0017] In some embodiments, the convex portion is an annular structure.

[0018] In the above technical solution, the convex portion is an annular structure, and any position on the circumference of the convex portion can be welded to the end cap, reducing the welding difficulty. Of course, the end cap and the convex portion can also be welded along the circumference of the convex portion, improving the firmness after welding the end cap and the current collecting member.

[0019] In some embodiments, the end cap has a second abutting surface, and the current collecting member abuts against the second abutting surface and is welded to the end cap to form the third welding portion; the end cap is provided with a third avoiding portion and a fourth avoiding portion that are recessed from the second abutting surface in a direction away from the current collecting member, the third avoiding portion is used to avoid the first welding portion, and the fourth avoiding portion is used to avoid the second welding portion.

[0020] In the above technical solution, the end cap is provided with a third avoiding portion and a fourth avoiding portion that are recessed from the second abutting surface in a direction away from the current collecting member. The third avoiding portion and the fourth avoiding portion can respectively avoid the first welding portion and the second welding portion, ensuring good contact between the second abutting surface and the current collecting member. The third avoiding portion and the fourth avoiding portion are provided on the end cap, which can simplify the structure of the current collecting member.

[0021] In some embodiments, the current collecting member is a flat plate structure.

[0022] In the above technical solution, the current collecting member is a flat plate structure, which has a simple structure and is easy to form and manufacture.

[0023] In some embodiments, the end cap includes: a cap body for covering the opening; a terminal portion protruding from the outer surface of the cap body in a direction away from the electrode assembly; the third welding portion is located on the outer peripheral side of the terminal portion, and in the thickness direction of the end cap, the projection of the terminal portion partially or completely covers the first welding portion.

[0024] In the above technical solution, the terminal portion of the end cap is used to connect to other components to output the electrical energy of the battery cell. The third welding portion is located on the outer peripheral side of the terminal portion. The thickness of the portion where the end cap is welded to the current collector member is relatively thin, ensuring the firmness after the end cap and the current collector member are welded. The projection of the terminal portion in the thickness direction of the end cap partially or completely covers the first welding portion, making the radial dimension of the terminal portion larger, facilitating connection to other components to output electrical energy.

[0025] In some embodiments, a welding groove is provided on the end cap, and a fourth connecting portion is formed at the bottom of the welding groove of the end cap. The fourth connecting portion is used to be welded to the current collector member to form the third welding portion.

[0026] In the above technical solution, the setting of the welding groove on the end cap, on the one hand, reduces the thickness of the portion of the end cap used for welding to the current collector member, increases the depth of the portion of the third welding portion located inside the current collector member, and improves the firmness after the end cap and the current collector member are welded. On the other hand, the position where the welding groove is located is the welding position of the end cap and the current collector member. When welding the end cap and the current collector member, the welding position where the end cap needs to be welded to the current collector member can be quickly found, improving the welding efficiency.

[0027] In some embodiments, the first welding portion is an annular structure; or, the first welding portion includes a plurality of first welding segments distributed at intervals in the circumferential direction, and the first welding segments are configured to connect the current collector member and the tab.

[0028] In the above technical solution, the first welding portion being an annular structure enables the current collector member and the tab to have good firmness after welding and has a relatively large current-carrying area. The first welding portion includes a plurality of first welding segments distributed at intervals in the circumferential direction. The current collector member and the tab are welded at multiple positions in the circumferential direction to form a first welding segment corresponding to each position, which not only ensures good firmness after the current collector member and the tab are welded but also improves the welding efficiency of the current collector member and the tab.

[0029] In some embodiments, the second welding portion is an annular structure; or, the second welding portion includes a plurality of second welding segments distributed at intervals in the circumferential direction, and the second welding segments are configured to connect the current collector member and the tab.

[0030] In the above technical solution, the second welding portion being an annular structure enables the current collector member and the tab to have good firmness after welding and has a relatively large current-carrying area. The second welding portion includes a plurality of second welding segments distributed at intervals in the circumferential direction. The current collector member and the tab are welded at multiple positions in the circumferential direction to form a second welding segment corresponding to each position, which not only ensures good firmness after the current collector member and the tab are welded but also improves the welding efficiency of the current collector member and the tab.

[0031] In some embodiments, the third welding portion is an annular structure; or, the third welding portion includes a plurality of third welding segments spaced circumferentially, and the third welding segments are configured to connect the current collecting member and the end cap.

[0032] In the above technical solution, the third welding portion is an annular structure, so that the end cap and the current collecting member have good firmness after welding and have a large current-carrying area. The third welding portion includes a plurality of third welding segments spaced circumferentially. The end cap and the current collecting member are welded at multiple positions in the circumferential direction, and a third welding segment is formed corresponding to each position, which not only ensures good firmness of the end cap and the current collecting member after welding, but also improves the welding efficiency of the end cap and the current collecting member.

[0033] In a second aspect, an embodiment of the present application provides a battery, including: a battery cell provided in any one of the first aspects; and a box body for accommodating the battery cell.

[0034] In a third aspect, an embodiment of the present application provides an electrical device, including the battery provided in any one of the second aspects.

[0035] In a fourth aspect, an embodiment of the present application provides a method for manufacturing a battery cell, the method including: providing a housing having an opening; providing an electrode assembly having a tab; providing an end cap; providing a current collecting member; welding the current collecting member and the tab to form a first welding portion and a second welding portion; accommodating the electrode assembly in the housing; covering the end cap on the opening; welding the end cap and the current collecting member to form a third welding portion; wherein, the first welding portion is located on the inner circumferential side of the third welding portion, and the second welding portion is located on the outer circumferential side of the third welding portion.

[0036] In a fifth aspect, an embodiment of the present application provides a manufacturing device for a battery cell, the manufacturing device including: a first providing device for providing a housing having an opening; a second providing device for providing an electrode assembly having a tab; a third providing device for providing an end cap; a fourth providing device for providing a current collecting member; an assembling device for welding the current collecting member and the tab to form a first welding portion and a second welding portion; and further for accommodating the electrode assembly in the housing; and further for covering the end cap on the opening; and further for welding the end cap and the current collecting member to form a third welding portion; wherein, the first welding portion is located on the inner circumferential side of the third welding portion, and the second welding portion is located on the outer circumferential side of the third welding portion. Description of the Drawings

[0037] To more clearly illustrate the technical solutions of the embodiments of the present application, the accompanying drawings required for the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation of the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0038] Figure 1 Structural schematic diagram of a vehicle provided by some embodiments of the present application;

[0039] Figure 2 Structural schematic diagram of a battery provided by some embodiments of the present application;

[0040] Figure 3 Explosion diagram of a battery cell provided by some embodiments of the present application;

[0041] Figure 4 Partial schematic diagram of a battery cell provided by some embodiments of the present application;

[0042] Figure 5 Partial schematic diagram of a battery cell provided by other embodiments of the present application;

[0043] Figure 6 Distribution diagram of a first welding part, a second welding part and a third welding part provided by some embodiments of the present application;

[0044] Figure 7 Distribution diagram of a first welding part, a second welding part and a third welding part provided by other embodiments of the present application;

[0045] Figure 8 Flow chart of a manufacturing method of a battery cell provided by some embodiments of the present application;

[0046] Figure 9 Structural schematic diagram of a manufacturing device of a battery cell provided by some embodiments of the present application.

[0047] Icons: 10 - box body; 11 - first part; 12 - second part; 20 - battery cell; 21 - housing; 22 - electrode assembly; 221 - tab; 23 - end cap; 231 - second abutting surface; 232 - third avoidance portion; 233 - fourth avoidance portion; 234 - cap body; 235 - terminal portion; 236 - welding groove; 237 - fourth connecting portion; 24 - current collecting member; 241 - body portion; 2411 - first connecting portion; 2412 - second connecting portion; 242 - convex portion; 2421 - first abutting surface; 2422 - third connecting portion; 243 - first avoidance portion; 244 - second avoidance portion; 245 - concave portion; 25 - first welding portion; 251 - first welding section; 26 - second welding portion; 261 - second welding section; 27 - third welding portion; 271 - third welding section; 100 - battery; 200 - controller; 300 - motor; 1000 - vehicle; 2000 - manufacturing equipment; 2100 - first providing device; 2200 - second providing device; 2300 - third providing device; 2400 - fourth providing device; 2500 - assembling device; Z - thickness direction. Detailed implementation manners

[0048] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0049] Unless otherwise defined, all technical and scientific terms used in the present application have the same meanings as those commonly understood by those skilled in the technical field to which the present application belongs; the terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application; the terms "including" and "having" and any variations thereof in the specification and claims of the present application and the above drawings are intended to cover non - exclusive inclusion. The terms "first", "second", etc. in the specification and claims of the present application or the above drawings are used to distinguish different objects and are not used to describe a specific order or primary - secondary relationship.

[0050] Referring to "embodiments" in the present application means that specific features, structures or characteristics described in connection with the embodiments can be included in at least one embodiment of the present application. The phrase appears in various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments.

[0051] In the description of the present application, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", "joined", and "attached" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0052] In the embodiments of the present application, the same reference numerals denote the same components, and for the sake of brevity, in different embodiments, the detailed description of the same components is omitted. It should be understood that the thicknesses, lengths, widths, etc. of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width, etc. of the integrated device are only illustrative descriptions and should not constitute any limitation to the present application.

[0053] The term "a plurality of" as used in the present application means two or more (including two).

[0054] In the present application, 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, a magnesium-ion battery, etc., and the embodiments of the present application do not limit this. The battery cell can be in a cylindrical shape, a flat shape, a cuboid shape, or other shapes, etc., and the embodiments of the present application do not limit this either. Generally, the battery cell is divided into three types according to the packaging method: cylindrical battery cell, square battery cell, and soft-pack battery cell, and the embodiments of the present application do not limit this either.

[0055] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide a higher voltage and capacity. For example, the battery mentioned in the present application may include a battery module or a battery pack, etc. The battery generally includes a box body for encapsulating one or more battery cells. The box body can prevent liquids or other foreign objects from affecting the charging or discharging of the battery cells.

[0056] The battery cell includes an electrode assembly and an electrolyte. The electrode assembly is composed of a positive electrode plate, a negative electrode plate, and a separator. The battery cell mainly operates by the movement of metal ions between the positive electrode plate and the negative electrode plate. The positive electrode plate includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive current collector. The positive current collector without the coated positive active material layer protrudes from the positive current collector with the coated positive active material layer. The positive current collector without the coated positive active material layer serves as the positive electrode tab. Taking a lithium-ion battery as an example, the material of the positive current collector can be aluminum, and the positive active material can be lithium cobaltate, lithium iron phosphate, ternary lithium, lithium manganate, etc. The negative electrode plate includes a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative current collector. The negative current collector without the coated negative active material layer protrudes from the negative current collector with the coated negative active material layer. The negative current collector without the coated negative active material layer serves as the negative electrode tab. The material of the negative current collector can be copper, and the negative active material can be carbon or silicon, etc. To ensure that large currents can pass through without fusing, the number of positive electrode tabs is multiple and they are stacked together, and the number of negative electrode tabs is multiple and they are stacked together. The material of the separator can be PP (polypropylene) or PE (polyethylene), etc. In addition, the electrode assembly can be a wound structure or a stacked structure, and the embodiments of the present application are not limited thereto.

[0057] The development of battery technology needs to consider various design factors simultaneously. For example, performance parameters such as energy density, cycle life, discharge capacity, charge-discharge rate, etc. In addition, the safety of the battery also needs to be considered.

[0058] The inventors found that for general battery cells, during the charge-discharge cycle, the battery cells are prone to heat generation, which affects the life of the battery cells. The inventors further studied and found that in the battery cell, the end cap is directly welded to the electrode tab to output electrical energy through the end cap. However, due to the structural limitations of the end cap, the welding part formed by welding the end cap and the electrode tab (the part where the end cap and the electrode tab are welded to form a weld mark) is relatively far from the center of the electrode assembly, so that the movement path of electrons in the inner ring part of the electrode assembly to the end cap through the welding part is large, and the movement path of the electrodes in the outer ring part of the electrode assembly to the end cap through the welding part is small, resulting in an increase in the internal resistance of the battery cell and polarization phenomenon, thereby causing a large amount of heat to be generated during the charge-discharge process of the battery cell, affecting the life of the battery cell.

[0059] In view of this, an embodiment of the present application provides a battery cell. By connecting the end cap and the tab through a current collector member, the electrical connection between the end cap and the tab is realized. The current collector member is welded to the tab to form a first welding portion and a second welding portion, and the current collector member is welded to the end cap to form a third welding portion. The first welding portion is located on the inner peripheral side of the third welding portion, and the second welding portion is located on the outer peripheral side of the third welding portion. This enables the electrons in the inner ring part of the electrode assembly to move along the path of the tab, the first welding portion, the current collector member, the third welding portion, and the end cap, and the electrons in the outer ring part of the electrode assembly to move along the path of the tab, the second welding portion, the current collector member, the third welding portion, and the end cap. This equalizes the movement paths of the electrons in the inner ring part and the outer ring part of the electrode assembly, reduces the internal resistance of the battery cell, and effectively improves the lifespan of the battery cell.

[0060] The technical solutions described in the embodiments of the present application are applicable to batteries and electrical equipment using batteries.

[0061] The electrical equipment may be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, etc. The vehicle may be a fuel vehicle, a gas vehicle, or a new energy vehicle. The new energy vehicle may be a pure electric vehicle, a hybrid electric vehicle, or an extended-range electric vehicle, etc.; the spacecraft includes an airplane, a rocket, a space shuttle, a spaceship, etc.; the electric toy includes a fixed or mobile electric toy, for example, a game console, an electric vehicle toy, an electric ship toy, an electric airplane toy, etc.; the electric tool includes a metal cutting electric tool, a grinding electric tool, an assembly electric tool, and a railway electric tool, for example, an electric drill, an electric grinder, an electric wrench, an electric screwdriver, a hammer drill, an impact electric drill, a concrete vibrator, an electric planer, etc. The embodiments of the present application do not impose special restrictions on the above-mentioned electrical equipment.

[0062] For the convenience of description, the following embodiments take the electrical equipment as a vehicle as an example for illustration.

[0063] Please refer to Figure 1 , Figure 1 which is a schematic structural diagram of a vehicle 1000 provided by some embodiments of the present application. A battery 100 is disposed inside the vehicle 1000, and the battery 100 may be disposed at the bottom, the head, or the tail of the vehicle 1000. The battery 100 can be used to supply power to the vehicle 1000. For example, the battery 100 can be used as the operating power source of the vehicle 1000.

[0064] The vehicle 1000 may further 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, it is used for the working power requirements during the start, navigation, and driving of the vehicle 1000.

[0065] In some embodiments of the present application, the battery 100 can not only serve as the operating power source of the vehicle 1000, but also as the driving power source of the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0066] Please refer to Figure 2 , Figure 2 FIG. is a schematic structural diagram of the battery 100 provided in some embodiments of the present application. The battery 100 includes a box body 10 and battery cells 20. The box body 10 is used to accommodate the battery cells 20.

[0067] Among them, the box body 10 is a component for accommodating the battery cells 20. The box body 10 provides an accommodation space for the battery cells 20, and the box body 10 can adopt various structures. In some embodiments, the box body 10 can include a first part 11 and a second part 12. The first part 11 and the second part 12 are covered with each other to define an accommodation space for accommodating the battery cells 20. The first part 11 and the second part 12 can be of various shapes, such as a cuboid, a cylinder, etc. The first part 11 can be a hollow structure with one side open, and the second part 12 can also be a hollow structure with one side open. The open side of the second part 12 is covered on the open side of the first part 11, then the box body 10 with an accommodation space is formed. It can also be that the first part 11 is a hollow structure with one side open, and the second part 12 is a plate-like structure. The second part 12 is covered on the open side of the first part 11, then the box body 10 with an accommodation space is formed. The first part 11 and the second part 12 can be sealed through a sealing element, and the sealing element can be a sealing ring, a sealant, etc.

[0068] In the battery 100, the battery cells 20 can be one or multiple. If there are multiple battery cells 20, the multiple battery cells 20 can be connected in series, in parallel, or in a mixed connection. A mixed connection means that there are both series and parallel connections among the multiple battery cells 20. It can be that multiple battery cells 20 are first connected in series, in parallel, or in a mixed connection to form a battery module, and then multiple battery modules are connected in series, in parallel, or in a mixed connection to form a whole and are accommodated in the box body 10. It can also be that all the battery cells 20 are directly connected in series, in parallel, or in a mixed connection together, and then the whole formed by all the battery cells 20 is accommodated in the box body 10.

[0069] In some embodiments, the battery 100 can further include a busbar component. The multiple battery cells 20 can be electrically connected through the busbar component to achieve series, parallel, or mixed connection of the multiple battery cells 20. The busbar component can be a metal conductor, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0070] Please refer to Figure 3 , Figure 3An exploded view of the battery cell 20 provided by some embodiments of the present application. The battery cell 20 includes a housing 21, an electrode assembly 22, an end cap 23, and a current collector member 24.

[0071] The housing 21 is a component for accommodating the electrode assembly 22. The housing 21 can be a hollow structure with an opening formed at one end, or it can be a hollow structure with openings formed at both opposite ends. If the housing 21 is a hollow structure with an opening formed at one end, there can be one end cap 23, and the end cap 23 correspondingly covers the opening of the housing 21; if the housing 21 is a hollow structure with openings formed at both ends, there can be two end caps 23, and the two end caps 23 respectively cover the openings at both ends of the housing 21. The material of the housing 21 can be various, such as copper, iron, aluminum, steel, aluminum alloy, etc. The housing 21 can be in various shapes, such as a cylinder, a cuboid, etc. Exemplarily, in Figure 3 it, the housing 21 is a cylinder, and the housing 21 is a hollow structure with openings formed at both ends.

[0072] The electrode assembly 22 is a component in the battery cell 20 where an electrochemical reaction occurs. The electrode assembly 22 can include a positive electrode tab, a negative electrode tab, and a separator. The electrode assembly 22 can be a wound structure formed by winding the positive electrode tab, the separator, and the negative electrode tab, or it can be a stacked structure formed by stacking the positive electrode tab, the separator, and the negative electrode tab. The electrode assembly 22 can be in various shapes, such as a cylinder, a cuboid, etc. If the housing 21 is a cylinder, the electrode assembly 22 can be a cylinder; if the housing 21 is a cuboid, the electrode assembly 22 can be a cuboid.

[0073] The positive electrode tab can include a positive electrode current collector and positive electrode active material layers coated on opposite sides of the positive electrode current collector. The negative electrode tab can include a negative electrode current collector and negative electrode active material layers coated on opposite sides of the negative electrode current collector. The electrode assembly 22 includes tabs 221. The tabs 221 are divided into positive electrode tabs and negative electrode tabs. The positive electrode tab can be the part of the positive electrode tab where the positive electrode active material layer is not coated, and the negative electrode tab can be the part of the negative electrode tab where the negative electrode active material layer is not coated.

[0074] The end cap 23 is a component that covers the opening of the housing 21 to isolate the internal environment of the battery cell 20 from the external environment. The end cap 23 covers the opening of the housing 21, and the shape of the end cap 23 can be adapted to the shape of the housing 21. For example, if the housing 21 is a cuboid structure, the end cap 23 is a rectangular plate-like structure adapted to the housing 21. Again, such as Figure 3As shown, the housing 21 is a cylindrical structure, and the end cap 23 is a circular plate-like structure adapted to the housing 21. The material of the end cap 23 can also be various, such as copper, iron, aluminum, steel, aluminum alloy, etc. The material of the end cap 23 can be the same as or different from that of the housing 21. In the embodiment where there are two end caps 23 in the battery cell 20, the materials of the two end caps 23 can be the same or different.

[0075] The end cap 23 and the housing 21 can be hermetically connected through a seal. The seal can isolate the end cap 23 from the housing 21, and while achieving the sealing between the end cap 23 and the housing 21, it also achieves the insulation between the end cap 23 and the housing 21. The material of the seal can be plastic, rubber, etc.

[0076] The current collector member 24 is a component for realizing the electrical connection between the end cap 23 and the tab 221. The current collector member 24 can be one or two. In the embodiment where there is only one end cap 23 in the battery cell 20, the current collector member 24 can be one. One of the positive tab and the negative tab is connected to one end cap 23 through one current collector member 24, and the other is directly connected to the housing 21. In the embodiment where there are two end caps 23 in the battery cell 20, the current collector member 24 can be two. One of the positive tab and the negative tab is connected to one end cap 23 through one current collector member 24, and the other is connected to the other end cap 23 through the other current collector member 24. The current collector member 24 can be a metal conductor, such as copper, iron, aluminum, steel, aluminum alloy, etc. In the embodiment where there are two current collector members 24 in the battery cell 20, the materials and structures of the two current collector members 24 can be the same or different.

[0077] Please refer to Figure 4 , Figure 4 which is a partial schematic diagram of the battery cell 20 provided by some embodiments of the present application. The embodiments of the present application provide a battery cell 20, which includes a housing 21, an electrode assembly 22, an end cap 23, and a current collector member 24. The housing 21 has an opening, the electrode assembly 22 has tabs 221, the electrode assembly 22 is configured to be received in the housing 21, the end cap 23 is configured to cover the opening, and the current collector member 24 is configured to connect the end cap 23 and the tab 221 to achieve the electrical connection between the end cap 23 and the tab 221. Wherein, the current collector member 24 is welded to the tab 221 to form a first welding portion 25 and a second welding portion 26, and the current collector member 24 is welded to the end cap 23 to form a third welding portion 27. The first welding portion 25 is located on the inner peripheral side of the third welding portion 27, and the second welding portion 26 is located on the outer peripheral side of the third welding portion 27.

[0078] The current collecting member 24 is used to connect the end cap 23 and the tab 221 to achieve the electrical connection between the end cap 23 and the tab 221. The end cap 23 can be connected to the positive tab through the current collecting member 24, or the end cap 23 can be connected to the negative tab through the current collecting member 24.

[0079] The current collecting member 24 is welded to the tab 221 to form a first welding portion 25 and a second welding portion 26. Both the first welding portion 25 and the second welding portion 26 are parts where the current collecting member 24 is welded to the tab 221 to form welding imprints, and both the first welding portion 25 and the second welding portion 26 serve to connect the current collecting member 24 and the tab 221. The current collecting member 24 and the tab 221 can be welded by various welding methods. For example, the current collecting member 24 and the tab 221 can be welded by penetration welding, and the welding can be performed on the outer side of the current collecting member 24 (the side of the current collecting member 24 facing away from the tab) to weld the current collecting member 24 and the tab 221 together.

[0080] The current collecting member 24 is welded to the end cap 23 to form a third welding portion 27. The third welding portion 27 is the part where the current collecting member 24 is welded to the tab 221 to form a welding imprint, and the third welding portion 27 serves to connect the current collecting member 24 and the end cap 23. The current collecting member 24 and the end cap 23 can be welded by various welding methods. For example, the current collecting member 24 and the end cap 23 can be welded by penetration welding, and the welding can be performed on the outer side of the end cap 23 (the side of the end cap 23 facing away from the current collecting member) to weld the end cap 23 and the current collecting member 24 together.

[0081] The first welding part 25 is located on the inner circumferential side of the third welding part 27, that is, the third welding part 27 is located outside the first welding part 25 in the direction perpendicular to the thickness direction Z of the end cover 23. It can also be understood that the third welding part 27 is located outside the outer circumferential surface of the first welding part 25; the second welding part 26 is located on the outer circumferential side of the third welding part 27, that is, the second welding part 26 is located outside the third welding part 27 in the direction perpendicular to the thickness direction Z of the end cover 23. It can also be understood that the second welding part 26 is located outside the outer circumferential surface of the third welding part 27. That is to say, in the direction perpendicular to the thickness direction Z of the end cover 23, the first welding part 25, the third welding part 27, and the second welding part 26 are arranged in sequence from the inside to the outside. The first welding part 25, the second welding part 26, and the third welding part 27 can be coaxially arranged or eccentrically arranged. It should be noted that the first welding part 25 is located on the inner circumferential side of the third welding part 27, which defines the inner and outer relationship between the first welding part 25 and the third welding part 27, and does not limit the positional relationship between the first welding part 25 and the third welding part 27 in the thickness direction Z of the end cover 23. That is to say, there may or may not be a distance between the first welding part 25 and the third welding part 27 in the thickness direction Z of the end cover 23. Similarly, the second welding part 26 is located on the outer circumferential side of the third welding part 27, which defines the inner and outer relationship between the second welding part 26 and the third welding part 27, and does not limit the positional relationship between the second welding part 26 and the third welding part 27 in the thickness direction Z of the end cover 23. That is to say, there may or may not be a distance between the second welding part 26 and the third welding part 27 in the thickness direction Z of the end cover 23.

[0082] The first welding part 25 can be a closed structure that extends along the circumference and is connected end to end. For example, the first welding part 25 is an annular structure; the first welding part 25 can also be a non-closed structure that extends along the circumference and has a distance between the head and the tail. For example, the first welding part 25 is a semi-circular structure; of course, the first welding part 25 can also be divided into multiple segments that are circumferentially spaced apart. The second welding part 26 can be a closed structure that extends along the circumference and is connected end to end. For example, the second welding part 26 is an annular structure; the second welding part 26 can also be a non-closed structure that extends along the circumference and has a distance between the head and the tail. For example, the second welding part 26 is a semi-circular structure; of course, the second welding part 26 can also be divided into multiple segments that are circumferentially spaced apart. The third welding part 27 can be a closed structure that extends along the circumference and is connected end to end. For example, the third welding part 27 is an annular structure; the third welding part 27 can also be a non-closed structure that extends along the circumference and has a distance between the head and the tail. For example, the third welding part 27 is a semi-circular structure; of course, the third welding part 27 can also be divided into multiple segments that are circumferentially spaced apart.

[0083] The second welding portion 26 located on the outer peripheral side of the third welding portion 27 may be one turn or multiple turns. The first welding portion 25 located on the inner peripheral side of the third welding portion 27 may be one turn or multiple turns.

[0084] In the battery cell 20, the tab 221 and the end cap 23 are connected by a current collecting member 24, and the current collecting member 24 is welded to the tab 221 to form a first welding portion 25 and a second welding portion 26. The current collecting member 24 is welded to the end cap 23 to form a third welding portion 27. The first welding portion 25 and the second welding portion 26 are respectively located on the inner peripheral side and the outer peripheral side of the third welding portion 27, so that the electrons in the inner ring portion of the electrode assembly 22 can move along the paths of the tab 221, the first welding portion 25, the current collecting member 24, the third welding portion 27, and the end cap 23. The electrons in the outer ring portion of the electrode assembly 22 can move along the paths of the tab 221, the second welding portion 26, the current collecting member 24, the third welding portion 27, and the end cap 23. The movement paths of the electrons in the inner ring portion of the electrode assembly 22 and the movement paths of the electrons in the outer ring portion are basically the same, equalizing the movement paths of the electrons in the inner ring portion and the outer ring portion of the electrode assembly 22, reducing the internal resistance of the battery cell 20, and effectively improving the life of the battery cell 20.

[0085] In addition, since the current collecting member 24 and the tab 221 are connected together through the first welding portion 25 and the second welding portion 26, both the first welding portion 25 and the second welding portion 26 can conduct current, increasing the current-carrying capacity and meeting the requirements of high-rate overcurrent. Since the first welding portion 25 and the second welding portion 26 are respectively located on the inner peripheral side and the outer peripheral side of the third welding portion 27, the first welding portion 25, the second welding portion 26, and the third welding portion 27 do not overlap in the thickness direction Z of the end cap 23, reducing the risk that the welding between the end cap 23 and the current collecting member 24 is not firm due to the overlap of the third welding portion 27 with the first welding portion 25 or the second welding portion 26.

[0086] For a general battery cell 20, the welding portion formed by welding the current collecting member 24 and the tab 221 and the welding portion formed by welding the end cap 23 and the current collecting member 24 are basically located on the same circumference. To avoid the overlap of the welding portion formed by welding the current collecting member 24 and the tab 221 and the welding portion formed by welding the end cap 23 and the current collecting member 24 in the thickness direction Z of the end cap 23, when welding the end cap 23 and the current collecting member 24, it is necessary to find the welding position accurately to ensure that the welding portion formed by welding the end cap 23 and the current collecting member 24 is circumferentially staggered from the welding portion formed by welding the current collecting member 24 and the tab 221, resulting in a low welding efficiency.

[0087] In the battery cell 20 provided in the embodiment of the present application, since the first welding portion 25 is located on the inner peripheral side of the third welding portion 27, and the second welding portion 26 is located on the outer peripheral side of the third welding portion 27, during the actual welding process, after welding the current collector member 24 and the tab 221 to form the first welding portion 25 and the second welding portion 26, welding the end cap 23 and the current collector member 24 in the area between the first welding portion 25 and the second welding portion 26 can form the third welding portion 27 located on the outer peripheral side of the first welding portion 25 and on the inner peripheral side of the second welding portion 26, improving the welding efficiency of the end cap 23 and the current collector member 24, and thus improving the production efficiency.

[0088] In some embodiments, please continue to refer to Figure 4 , the current collector member 24 includes a body portion 241 and a convex portion 242. The body portion 241 is used to abut against and weld with the tab 221 to form the first welding portion 25 and the second welding portion 26. The convex portion 242 protrudes from the outer surface of the body portion 241 in the direction facing the end cap 23, and the convex portion 242 is used to abut against and weld with the end cap 23 to form the third welding portion 27.

[0089] The outer surface of the body portion 241 refers to the surface of the body portion 241 facing away from the tab 221. Of course, the body portion 241 also has an inner surface, and the inner surface of the body portion 241 refers to the surface in contact with the tab 221. The body portion 241 may be a plate-like structure.

[0090] The convex portion 242 protrudes from the outer surface of the body portion 241 in the direction facing the end cap 23. In other words, in the thickness direction Z of the end cap 23, the convex portion 242 extends from the outer surface of the body portion 241 in the direction close to the end cap 23.

[0091] In this embodiment, the body portion 241 is the part of the current collector member 24 welded to the tab 221, and the convex portion 242 is the part of the current collector member 24 welded to the end cap 23. The convex portion 242 of the current collector member 24 protrudes from the outer surface of the body portion 241 in the direction facing the end cap 23, and the abutment of the convex portion 242 with the end cap 23 can ensure good contact, facilitating the welding of the end cap 23 and the current collector member 24.

[0092] In some embodiments, please continue to refer to Figure 4 , the body portion 241 includes a first connection portion 2411 and a second connection portion 2412. The first connection portion 2411 is connected to the convex portion 242 and is located on the inner peripheral side of the convex portion 242. The first connection portion 2411 is used to abut against and weld with the tab 221 to form the first welding portion 25; the second connection portion 2412 is connected to the convex portion 242 and is located on the outer peripheral side of the convex portion 242. The second connection portion 2412 is used to abut against and weld with the tab 221 to form the second welding portion 26.

[0093] The first connecting portion 2411 is connected to the convex portion 242 and is located on the inner peripheral side of the convex portion 242. That is, the first connecting portion 2411 is connected to the convex portion 242, and in the direction perpendicular to the thickness direction Z of the end cover 23, the first connecting portion 2411 is located inside the convex portion 242. The second connecting portion 2412 is connected to the convex portion 242 and is located on the outer peripheral side of the convex portion 242. That is, the second connecting portion 2412 is connected to the convex portion 242, and in the direction perpendicular to the thickness direction Z of the end cover 23, the second connecting portion 2412 is located outside the convex portion 242.

[0094] The first connecting portion 2411, the convex portion 242, and the second connecting portion 2412 can be an integrally formed structure. Both the first connecting portion 2411 and the second connecting portion 2412 can be plate-like structures.

[0095] In this embodiment, the first connecting portion 2411 of the main body portion 241 is located on the inner peripheral side of the convex portion 242, and the second connecting portion 2412 of the main body portion 241 is located on the outer peripheral side of the convex portion 242. The first connecting portion 2411 and the second connecting portion 2412 are separated by the convex portion 242, so that the entire current collecting member 24 forms three welding regions with distinct boundaries. The three welding regions are the regions corresponding to the current collecting member 24 and the first connecting portion 2411, the convex portion 242, and the second connecting portion 2412 respectively. By welding the first connecting portion 2411 to the tab 221, the second connecting portion 2412 to the tab 221, and the end cover 23 to the convex portion 242, it can be ensured that the first welding portion 25 and the second welding portion 26 are respectively located on the inner peripheral side and the outer peripheral side of the third welding portion 27, which can improve the welding efficiency of the current collecting member 24 and the tab 221, as well as the welding efficiency of the end cover 23 and the current collecting member 24, and improve the productivity.

[0096] In some embodiments, please continue to refer to Figure 4 , the outer surface of the first connecting portion 2411 and the inner peripheral surface of the convex portion 242 jointly define a first avoidance portion 243, and the first avoidance portion 243 is used to avoid the first welding portion 25; the outer surface of the second connecting portion 2412 and the outer peripheral surface of the convex portion 242 jointly define a second avoidance portion 244, and the second avoidance portion 244 is used to avoid the second welding portion 26.

[0097] The outer surface of the first connecting portion 2411 refers to the surface of the first connecting portion 2411 facing away from the tab 221. The outer surface of the second connecting portion 2412 refers to the surface of the second connecting portion 2412 facing away from the tab 221. The convex portion 242 has a first abutting surface 2421 for abutting against the end cover 23. The inner peripheral surface of the convex portion 242 is the surface of the convex portion 242 connected between the first abutting surface 2421 and the outer surface of the first connecting portion 2411. The outer peripheral surface of the convex portion 242 is the surface of the convex portion 242 connected between the first abutting surface 2421 and the outer surface of the second connecting portion 2412.

[0098] The first avoidance portion 243 functions to avoid the first welding portion 25, such that at least part of the first welding portion 25 is received within the first avoidance portion 243. The first avoidance portion 243 may be a groove structure that is recessed from the first abutting surface 2421 of the convex portion 242 in a direction away from the end cap 23. The second avoidance portion 244 functions to avoid the second welding portion 26, such that at least part of the second welding portion 26 is received within the second avoidance portion 244. The second avoidance portion 244 may also be a groove structure that is recessed from the first abutting surface 2421 of the convex portion 242 in a direction away from the end cap 23.

[0099] Since the end cap 23 abuts against the convex portion 242, the end cap 23 closes the first avoidance portion 243, and the portion of the first welding portion 25 located within the first avoidance portion 243 is restricted within the first avoidance portion 243 by the end cap 23. Even if part of the first welding portion 25 comes off, it will not fall into the interior of the battery cell 20, and there is less risk that part of the first welding portion 25 will come off and fall into the interior of the battery cell 20, affecting the performance of the battery cell 20.

[0100] Since the outer surface of the first connecting portion 2411 and the inner peripheral surface of the convex portion 242 jointly define the first avoidance portion 243 for avoiding the first welding portion 25, good contact between the convex portion 242 and the end cap 23 is ensured, and the firmness after welding the end cap 23 and the current collecting member 24 is improved. Since the outer surface of the second connecting portion 2412 and the outer peripheral surface of the convex portion 242 jointly define the second avoidance portion 244 for avoiding the second welding portion 26, good contact between the convex portion 242 and the end cap 23 is ensured, and the firmness after welding the end cap 23 and the current collecting member 24 is improved.

[0101] In some embodiments, please continue to refer to Figure 4 , a concave portion 245 is formed at a position corresponding to the convex portion 242 of the current collecting member 24. The concave portion 245 is recessed from the inner surface of the body portion 241 in a direction facing the end cap 23. The convex portion 242 has a first abutting surface 2421 for abutting against the end cap 23, and the convex portion 242 has a third connecting portion 2422 located between the first abutting surface 2421 and the bottom surface of the concave portion 245. The third connecting portion 2422 is used for welding with the end cap 23 to form a third welding portion 27.

[0102] The bottom surface of the concave portion 245 is a surface connected to the side surface of the concave portion 245. The bottom surface of the concave portion 245 faces the tab 221 and has a distance from the tab 221. The convex portion 242 has a third connecting portion 2422 located between the first abutting surface 2421 and the bottom surface of the concave portion 245. The third connecting portion 2422 is the portion of the convex portion 242 located between the first abutting surface 2421 and the bottom surface of the concave portion 245. The concave portion 245 may be an annular groove, which has a simple structure and is easy to form and manufacture.

[0103] In the thickness direction Z of the end cap 23, the third connecting portion 2422 may be spaced apart from the first connecting portion 2411 and the second connecting portion 2412. The third connecting portion 2422 may also be a plate-like structure like the first connecting portion 2411 and the second connecting portion 2412.

[0104] The current collecting member 24 may be formed by stamping a sheet material. While a recess 245 is formed by stamping one side of the sheet material, a protrusion 242 is formed at a position corresponding to the recess 245 on the other side of the sheet material.

[0105] In this embodiment, the provision of the recess 245 in the current collecting member 24 can, on the one hand, reduce the weight of the current collecting member 24 and save materials, and on the other hand, the recess 245 can avoid the third welding portion 27, reducing the impact on the position where the current collecting member 24 and the tab 221 have been welded well when welding the end cap 23 and the protrusion 242.

[0106] In some embodiments, the protrusion 242 is an annular structure.

[0107] In this embodiment, the recess 245 may be an annular groove, the second connecting portion 2412 and the third connecting portion 2422 may be annular structures, and the first connecting portion 2411 may be an annular structure or a circular structure.

[0108] Since the protrusion 242 is an annular structure, any position in the circumferential direction of the protrusion 242 can be welded to the end cap 23, reducing the welding difficulty. Of course, the end cap 23 and the protrusion 242 can also be welded along the circumferential direction of the protrusion 242 to improve the firmness after welding the end cap 23 and the current collecting member 24.

[0109] In some embodiments, please refer to Figure 5 , Figure 5 is a partial schematic view of the battery cell 20 provided in some other embodiments of the present application. The end cap 23 has a second abutting surface 231. The current collecting member 24 abuts against the second abutting surface 231 and is welded to the end cap 23 to form a third welding portion 27. The end cap 23 is provided with a third avoiding portion 232 and a fourth avoiding portion 233 that are recessed from the second abutting surface 231 in a direction away from the current collecting member 24. The third avoiding portion 232 is used to avoid the first welding portion 25, and the fourth avoiding portion 233 is used to avoid the second welding portion 26.

[0110] The third avoidance portion 232 functions to avoid the first welding portion 25, such that at least a part of the first welding portion 25 is received within the third avoidance portion 232. The third avoidance portion 232 may be a groove structure that is recessed from the second abutting surface 231 in a direction away from the current collecting member 24. The fourth avoidance portion 233 functions to avoid the second welding portion 26, such that at least a part of the second welding portion 26 is received within the fourth avoidance portion 233. The fourth avoidance portion 233 may also be a groove structure that is recessed from the second abutting surface 231 in a direction away from the current collecting member 24.

[0111] It should be noted that in the case where two end caps 23 and two current collecting members 24 are provided in the battery cell 20, the structures of the two end caps 23 may be the same or different, and the structures of the two current collecting members 24 may also be the same or different. For example, one end cap 23 and one current collecting member 24 adopt Figure 5 the structure shown (the avoidance portions for avoiding the first welding portion 25 and the second welding portion 26 are provided on the end cap 23), and the other end cap 23 and the other current collecting member 24 adopt Figure 4 the structure shown (the avoidance portions for avoiding the first welding portion 25 and the second welding portion 26 are provided on the current collecting member 24).

[0112] Since the third avoidance portion 232 and the fourth avoidance portion 233 that are recessed from the second abutting surface 231 in a direction away from the current collecting member 24 are provided on the end cap 23, the third avoidance portion 232 and the fourth avoidance portion 233 can respectively avoid the first welding portion 25 and the second welding portion 26, ensuring good contact between the second abutting surface 231 and the current collecting member 24. The third avoidance portion 232 and the fourth avoidance portion 233 are provided on the end cap 23, which can simplify the structure of the current collecting member 24.

[0113] In some embodiments, please continue to refer to Figure 5 , the current collecting member 24 is a flat plate structure.

[0114] The current collecting member 24 being a flat plate structure means that the current collecting member 24 is a plate-like structure with a substantially uniform thickness. If the outer surface and the inner surface of the current collecting member 24 are arranged in parallel, the thickness of the current collecting member 24 can be made substantially uniform.

[0115] In this embodiment, the current collecting member 24 is a flat plate structure, which has a simple structure and is easy to form and manufacture.

[0116] It should be noted that in other embodiments, when the third avoidance portion 232 and the fourth avoidance portion 233 for avoiding the first welding portion 25 and the second welding portion 26 are provided on the end cap 23 respectively, the first avoidance portion 243 and the second avoidance portion 244 for avoiding the first welding portion 25 and the second welding portion 26 can also be provided on the current collecting member 24, so that the whole structure has a larger avoidance space for avoiding the first welding portion 25 and the second welding portion 26.

[0117] In some embodiments, please continue to refer to Figure 4 and Figure 5 , the end cap 23 includes a cap body 234 and a terminal portion 235. The cap body 234 is used to cover the opening of the housing 21, and the terminal portion 235 protrudes from the outer surface of the cap body 234 in a direction away from the electrode assembly 22. The third welding portion 27 is located on the outer peripheral side of the terminal portion 235. In the thickness direction Z of the end cap 23, the projected portion of the terminal portion 235 covers the first welding portion 25 partially or entirely.

[0118] The terminal portion 235 is the part of the end cap 23 for outputting the electric energy of the battery cell 20. The terminal portion 235 is used to be connected to other components. For example, the terminal portion 235 is connected to a bus bar component. The cap body 234 is the part of the end cap 23 for being connected to the housing 21 and covering the opening of the housing 21. The terminal portion 235 and the cap body 234 can be an integrally formed structure or a split structure and connected together. For example, the terminal portion 235 and the cap body 234 are welded. The terminal portion 235 can be located at the central position of the cap body 234. In an embodiment where the electrode assembly 22 is a cylindrical structure, the tab 221 can be an annular structure, and the terminal portion 235 can be coaxially arranged with the tab 221.

[0119] In this embodiment, the third welding portion 27 is located on the outer peripheral side of the terminal portion 235, and the thickness of the portion where the end cap 23 is welded to the current collecting member 24 is relatively thin, ensuring the firmness after the end cap 23 and the current collecting member 24 are welded. The projected portion of the terminal portion 235 in the thickness direction Z of the end cap 23 covers the first welding portion 25 partially or entirely, so that the radial dimension of the terminal portion 235 is relatively large, facilitating connection to other components (such as a bus bar component) to output electric energy.

[0120] For a general battery cell 20, to achieve electrical connection between the end cap 23 and the tab 221, direct welding of the end cap 23 and the tab 221 can be adopted. However, since the thickness of the end cap 23 is relatively thick in the region of the terminal portion 235, welding cannot be performed between the end cap 23 in the region of the terminal portion 235 and the tab 221. The end cap 23 can only weld the cap body 234 and the tab 221 to form a welded portion. The welded portion formed by welding the cap body 234 and the tab 221 can only be located on the outer peripheral side of the terminal portion 235, making the welded portion far from the center of the electrode assembly 22 and increasing the internal resistance of the battery cell 20. However, in this embodiment, since the end cap 23 and the tab 221 are connected by the current collector member 24, the position of the first welded portion 25 formed by welding the current collector member 24 and the tab 221 is no longer restricted by the structure of the end cap 23. The projection of the terminal portion 235 in the thickness direction Z of the end cap 23 partially or entirely covers the first welded portion 25, enabling the first welded portion 25 to be closer to the center position of the electrode assembly 22, which is beneficial to reducing the internal resistance of the battery cell 20.

[0121] In some embodiments, please continue to refer to Figure 4 and Figure 5 , a welding groove 236 is provided on the end cap 23, and a fourth connecting portion 237 is formed at the bottom of the welding groove 236. The fourth connecting portion 237 is used to weld with the current collector member 24 to form a third welded portion 27.

[0122] The fourth connecting portion 237 is the part where the end cap 23 is welded to the current collector member 24. The part between the bottom surface of the welding groove 236 and the surface where the end cap 23 abuts against the current collector member 24 is the fourth connecting portion 237. As Figure 5 shown, taking the surface where the end cap 23 abuts against the current collector member 24 as the second abutting surface 231 as an example, the part between the bottom surface of the welding groove 236 of the end cap 23 and the second abutting surface 231 is the fourth connecting portion 237. Taking the example of adopting penetration welding to realize the welding between the end cap 23 and the current collector member 24, since the thickness of the fourth connecting portion 237 is relatively thinner than the thickness of other parts of the end cap 23, it is easier to penetrate the end cap 23 during welding to connect the end cap 23 and the current collector member 24 together.

[0123] In the embodiment where the end cap 23 includes a cap body 234 and a terminal portion 235, the welding groove 236 can be recessed from the outer surface of the cap body 234 in the direction facing the electrode assembly 22.

[0124] The provision of the welding groove 236 on the end cap 23 reduces the thickness of the part of the end cap 23 for welding with the current collecting member 24 on the one hand, increases the depth of the part of the third welding portion 27 located inside the current collecting member 24, and improves the firmness after welding the end cap 23 and the current collecting member 24. On the other hand, the position where the welding groove 236 is located is the welding position of the end cap 23 and the current collecting member 24. When welding the end cap 23 and the current collecting member 24, the welding position where the end cap 23 needs to be welded with the current collecting member 24 can be quickly found, improving the welding efficiency.

[0125] In some embodiments, please refer to Figure 6 , Figure 6 which is a distribution diagram of the first welding portion 25, the second welding portion 26 and the third welding portion 27 provided for some embodiments of the present application. The first welding portion 25 is an annular structure, so that after the current collecting member 24 is welded to the tab 221, it has good firmness and a large current-carrying area.

[0126] In some other embodiments, please refer to Figure 7 , Figure 7 which is a distribution diagram of the first welding portion 25, the second welding portion 26 and the third welding portion 27 provided for some other embodiments of the present application. The first welding portion 25 includes a plurality of first welding segments 251 distributed at intervals in the circumferential direction. The first welding segments 251 are configured to connect the current collecting member 24 and the tab 221. The current collecting member 24 and the tab 221 are welded at multiple positions in the circumferential direction to form a first welding segment 251 at each position, which not only ensures good firmness after welding the current collecting member 24 and the tab 221, but also improves the welding efficiency of the current collecting member 24 and the tab 221.

[0127] In some embodiments, please continue to refer to Figure 6 , the second welding portion 26 is an annular structure, so that after the current collecting member 24 is welded to the tab 221, it has good firmness and a large current-carrying area.

[0128] In some other embodiments, please continue to refer to Figure 7 , the second welding portion 26 includes a plurality of second welding segments 261 distributed at intervals in the circumferential direction. The second welding segments 261 are configured to connect the current collecting member 24 and the tab 221. The current collecting member 24 and the tab 221 are welded at multiple positions in the circumferential direction to form a second welding segment 261 at each position, which not only ensures good firmness after welding the current collecting member 24 and the tab 221, but also improves the welding efficiency of the current collecting member 24 and the tab 221.

[0129] In some embodiments, please continue to refer to Figure 6 , the third welding portion 27 is an annular structure, so that after the end cap 23 is welded to the current collecting member 24, it has good firmness and a large current-carrying area.

[0130] Exemplarily, in the thickness direction Z ( Figure 6 not shown) of the end cap 23, the projection of the third welding portion 27 divides the tab 221 ( Figure 6 not shown) into two parts with equal areas. In other words, the area of the portion of the tab 221 located on the inner circumferential side of the third welding portion 27 is equal to the area of the portion of the tab 221 located on the outer circumferential side of the third welding portion 27.

[0131] In some other embodiments, please continue to refer to Figure 7 , the third welding portion 27 includes a plurality of third welding segments 271 that are circumferentially spaced apart. The third welding segments 271 are configured to connect the current collecting member 24 and the end cap 23. The end cap 23 and the current collecting member 24 are welded at multiple positions in the circumferential direction to form a third welding segment 271 at each position, which not only ensures good firmness after welding the end cap 23 and the current collecting member 24, but also improves the welding efficiency of the end cap 23 and the current collecting member 24.

[0132] An embodiment of the present application provides a battery 100, including a box body 10 and the battery cell 20 provided in any one of the above embodiments. The box body 10 is used to accommodate the battery cell 20.

[0133] An embodiment of the present application provides an electrical device, including the battery 100 provided in any one of the above embodiments.

[0134] The electrical device can be any of the devices using the battery 100 above.

[0135] In addition, please refer to Figure 3 , an embodiment of the present application further provides a cylindrical battery, including a housing 21, an electrode assembly 22, two end caps 23, and two current collecting members 24. The housing 21 has two openings arranged oppositely. The two end caps 23 are respectively used to cover the two openings. The electrode assembly 22 is used to be accommodated in the housing 21. The electrode assembly 22 has two tabs 221 arranged oppositely and with opposite polarities. One tab 221 is electrically connected to one end cap 23 through one current collecting member 24, and the other tab 221 is electrically connected to the other end cap 23 through the other current collecting member 24. Among them, please refer to Figure 4 and Figure 5 , the current collecting member 24 is welded to the tab 221 to form a first welding portion 25 and a second welding portion 26, and the current collecting member 24 is welded to the end cap 23 to form a third welding portion 27. The first welding portion 25 is located on the inner circumferential side of the third welding portion 27, and the second welding portion 26 is located on the outer circumferential side of the third welding portion 27. The cylindrical battery with this structure has a smaller internal resistance and a longer service life.

[0136] An embodiment of the present application provides a manufacturing method for the battery cell 20. Please refer to Figure 8, Figure 8 A flowchart of a manufacturing method of a battery cell 20 provided for some embodiments of the present application. The manufacturing method of the battery cell 20 includes:

[0137] S100: Provide a housing 21 having an opening;

[0138] S200: Provide an electrode assembly 22 having a tab 221;

[0139] S300: Provide an end cap 23;

[0140] S400: Provide a current collector member 24;

[0141] S500: Weld the current collector member 24 to the tab 221 of the electrode assembly 22 to form a first welding portion 25 and a second welding portion 26;

[0142] S600: Accommodate the electrode assembly 22 in the housing 21;

[0143] S700: Cover the end cap 23 on the opening of the housing 21;

[0144] S800: Weld the end cap 23 to the current collector member 24 to form a third welding portion 27.

[0145] Wherein, the first welding portion 25 is located on the inner circumferential side of the third welding portion 27, and the second welding portion 26 is located on the outer circumferential side of the third welding portion 27.

[0146] In the above method, the order of steps S100, S200, S300, and S400 is not limited. For example, step S400 can be executed first, then step S300, then step S200, and then step S100.

[0147] It should be noted that for the related structures of the battery cell 20 manufactured by the manufacturing methods provided in the above embodiments, reference can be made to the battery cell 20 provided in the foregoing embodiments, which will not be elaborated herein.

[0148] In addition, an embodiment of the present application provides a manufacturing device 2000 for a battery cell 20. Please refer to Figure 9 , Figure 9Schematic structural diagram of a manufacturing apparatus 2000 for a battery cell 20 provided in some embodiments of the present application. The manufacturing apparatus 2000 includes a first providing device 2100, a second providing device 2200, a third providing device 2300, a fourth providing device 2400, and an assembling device 2500. The first providing device 2100 is configured to provide a housing 21 having an opening. The second providing device 2200 is configured to provide an electrode assembly 22 having a tab 221. The third providing device 2300 is configured to provide an end cap 23. The fourth providing device 2400 is configured to provide a current collecting member 24. The assembling device 2500 is configured to weld the current collecting member 24 to the tab 221 to form a first welding portion 25 and a second welding portion 26. The assembling device 2500 is further configured to accommodate the electrode assembly 22 within the housing 21. The assembling device 2500 is further configured to cover the end cap 23 on the opening. The assembling device 2500 is further configured to weld the end cap 23 to the current collecting member 24 to form a third welding portion 27. Among them, the first welding portion 25 is located on the inner circumferential side of the third welding portion 27, and the second welding portion 26 is located on the outer circumferential side of the third welding portion 27.

[0149] It should be noted that for the related structure of the battery cell 20 manufactured by the manufacturing apparatus 2000 provided by the above embodiments, reference may be made to the battery cell 20 provided in the foregoing embodiments, which will not be elaborated herein.

[0150] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments may be combined with each other.

[0151] The above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit the present application. For those skilled in the art, various modifications and changes can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A battery cell, characterized in that, Comprising: A housing having an opening; An electrode assembly having a tab, the electrode assembly being adapted to be received within the housing; An end cap for closing the opening; A current collecting member for connecting the end cap and the tab to effect electrical connection between the end cap and the tab; Wherein, the current collecting member is welded to the tab to form a first welding portion and a second welding portion, the current collecting member is welded to the end cap to form a third welding portion, the first welding portion is located on the inner circumferential side of the third welding portion, the second welding portion is located on the outer circumferential side of the third welding portion, and in the thickness direction of the end cap, the projections of the first welding portion, the second welding portion and the third welding portion on the end cap do not overlap each other.

2. The battery cell according to claim 1, wherein The current collecting member includes: A body portion for abutting against and welding to the tab to form the first welding portion and the second welding portion; A convex portion protruding from the outer surface of the body portion in a direction facing the end cap, the convex portion for abutting against and welding to the end cap to form the third welding portion.

3. The battery cell according to claim 2, wherein The body portion includes: A first connecting portion connected to the convex portion and located on the inner circumferential side of the convex portion, the first connecting portion for abutting against and welding to the tab to form the first welding portion; A second connecting portion connected to the convex portion and located on the outer circumferential side of the convex portion, the second connecting portion for abutting against and welding to the tab to form the second welding portion.

4. The battery cell according to claim 3, characterized in that, The outer surface of the first connecting portion and the inner circumferential surface of the convex portion together define a first avoidance portion for avoiding the first welding portion; The outer surface of the second connecting portion and the outer circumferential surface of the convex portion together define a second avoidance portion for avoiding the second welding portion.

5. The battery cell according to claim 2, characterized in that, A concave portion is formed at a position corresponding to the convex portion of the current collecting member, the concave portion being recessed from the inner surface of the body portion in a direction facing the end cap; The convex portion has a first abutting surface for abutting against the end cap, and the convex portion has a third connecting portion located between the first abutting surface and the bottom surface of the concave portion, the third connecting portion for welding to the end cap to form the third welding portion.

6. The battery cell according to claim 5, characterized in that The concave portion is an annular groove.

7. The battery cell according to claim 2, characterized in that, The convex portion is an annular structure.

8. The battery cell according to claim 1, wherein The end cap has a second abutting surface, the current collecting member abuts against the second abutting surface and is welded to the end cap to form the third welding portion; The end cap is provided with a third avoidance portion and a fourth avoidance portion recessed from the second abutting surface in a direction away from the current collecting member, the third avoidance portion for avoiding the first welding portion, and the fourth avoidance portion for avoiding the second welding portion.

9. The battery cell according to claim 8, wherein, The current collecting member is a flat plate structure.

10. The battery cell according to any one of claims 1-9, characterized in that, The end cap includes: A cap body for closing the opening; A terminal portion protruding from the outer surface of the cap body in a direction away from the electrode assembly; The third welding portion is located on the outer circumferential side of the terminal portion, and in the thickness direction of the end cap, the projection of the terminal portion partially or entirely covers the first welding portion.

11. The battery cell according to any one of claims 1-9, characterized in that, The end cap is provided with a welding groove, and the end cap forms a fourth connecting portion at the bottom of the welding groove. The fourth connecting portion is used to be welded to the current collector member to form the third welding portion.

12. The battery cell according to any one of claims 1-9, characterized in that, The first welding portion is an annular structure; or, the first welding portion includes a plurality of first welding segments that are circumferentially spaced apart, and the first welding segments are configured to connect the current collector member and the tab.

13. The battery cell according to any one of claims 1-9, characterized in that, The second welding portion is an annular structure; or, the second welding portion includes a plurality of second welding segments that are circumferentially spaced apart, and the second welding segments are configured to connect the current collector member and the tab.

14. The battery cell according to any one of claims 1-9, characterized in that, The third welding portion is an annular structure; or, the third welding portion includes a plurality of third welding segments that are circumferentially spaced apart, and the third welding segments are configured to connect the current collector member and the end cap.

15. A battery, comprising: The battery cell according to any one of claims 1-14; And A box body for accommodating the battery cell.

16. An electrical device, comprising the battery according to claim 15.

17. A method for manufacturing a battery cell, the method comprising: Providing a housing having an opening; Providing an electrode assembly having tabs; Providing an end cap; Providing a current collector member; Welding the current collector member to the tab to form a first welding portion and a second welding portion; Placing the electrode assembly in the housing; Closing the end cap on the opening; Welding the end cap to the current collector member to form a third welding portion; Wherein, the first welding portion is located on the inner circumferential side of the third welding portion, the second welding portion is located on the outer circumferential side of the third welding portion, and in the thickness direction of the end cap, the projections of the first welding portion, the second welding portion, and the third welding portion on the end cap do not overlap each other.

18. A manufacturing device for a battery cell, characterized in that, The manufacturing equipment includes: A first providing device for providing a housing having an opening; A second providing device for providing an electrode assembly having tabs; A third providing device for providing an end cap; A fourth providing device for providing a current collector member; An assembling device for welding the current collector member to the tab to form a first welding portion and a second welding portion; and for placing the electrode assembly in the housing; and for closing the end cap on the opening; and for welding the end cap to the current collector member to form a third welding portion; Wherein, the first welding portion is located on the inner circumferential side of the third welding portion, the second welding portion is located on the outer circumferential side of the third welding portion, and in the thickness direction of the end cap, the projections of the first welding portion, the second welding portion, and the third welding portion on the end cap do not overlap each other.

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