Battery cell, battery, power consumption device, and method and device for manufacturing battery cell

Abstract

The present application provides a battery cell, a battery, a power consumption device, and a manufacturing method and device for the battery cell, which belong to the battery technical field. The battery cell includes a housing, an electrode assembly, an end cap, and a current collecting element. The housing has an opening, and the electrode assembly has a tab. The electrode assembly is adapted to be housed in the housing, the end cap is adapted to cover the opening, and the current collecting element is adapted to connect the connecting end cap and the tab to realize an electrical connection between the end cap and the tab. The current collecting element and the tab are welded to form a first weld and a second weld, and the current collecting element and the end cap are welded to form a third weld, the first weld being located on the inner periphery of the third weld, and the second weld being located on the outer periphery of the third weld. A battery cell with this structure can uniform the movement paths of 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 battery cell's lifespan.

Description

[Technical field]

[0001] The present application relates to the field of battery technology, and in particular to battery cells, batteries, power consuming devices, and methods and devices for manufacturing battery cells. [Background technology]

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

[0003] In battery technology, not only do we need to consider the safety of the battery cells, but we also need to consider the service life of the battery cells, so how to improve the service life of the battery cells has become one of the problems in battery technology that needs to be solved quickly. Summary of the Invention

[0004] The embodiments of the present application provide a battery cell, a battery, a power consuming device, and a manufacturing method and device for the battery cell, which can effectively improve the service life of the battery cell.

[0005] According to a first aspect, an embodiment of the present application provides a battery cell, the battery cell including a housing having an opening, an electrode assembly for receiving in the housing having a tab, an end cap for covering the opening, and a current collecting part for connecting the end cap and the tab to realize an electrical connection between the end cap and the tab, wherein the current collecting part and the tab are welded to form a first weld and a second weld, the current collecting part and the end cap are welded to form a third weld, the first weld is located on an inner peripheral side of the third weld, and the second weld is located on an outer peripheral side of the third weld.

[0006] In the above technical solution, the current collecting part and the tab are welded to form a first weld and a second weld, and the current collecting part and the end cap are welded to form a third weld, and the first weld and the second weld are located on the inner and outer peripheral sides of the third weld, respectively. Thus, electrons in the inner ring part of the electrode assembly can move along a path from the tab, the first weld, the current collecting part, the third weld and the end cap, and electrons in the outer ring part of the electrode assembly can move along a path from the tab, the second weld, the current collecting part, the third weld and the end cap, thereby making the movement paths of the electrons in the inner ring part and the electrons in the outer ring part of the electrode assembly uniform, reducing the internal resistance of the battery cell, and effectively improving the service life of the battery cell.

[0007] In some examples, the current collecting part includes a body portion for abutting and welding to the tab to form the first weld and the second weld, and a protrusion protruding from an outer surface of the body portion in a direction facing the end cap, for abutting and welding to the end cap to form the third weld.

[0008] In the above technical solution, the main body is the part that welds the current collecting part and the tab, and the convex part is the part that welds the current collecting part and the end cap. The convex part of the current collecting part protrudes from the outer surface of the main body along the direction facing the end cap, and the abutment of the convex part with the end cap ensures good contact and makes it easy to weld the end cap and the current collecting part together.

[0009] In some embodiments, the main body includes a first connection portion connected to the protrusion and located on an inner circumferential side of the protrusion, for abutting and welding to the tab to form a first welded portion, and a second connection portion connected to the protrusion and located on an outer circumferential side of the protrusion, for abutting and welding to the tab to form the second welded portion.

[0010] In the above technical solution, the first connection portion of the main body is located on the inner side of the convex portion, and the second connection portion of the main body is located on the outer side of the convex portion. The first connection portion and the second connection portion are separated by the convex portion, thereby forming three clearly separated welding areas across the entire current collecting part. The three welding areas correspond to the first connection portion, the convex portion and the second connection portion of the current collecting part, respectively. By welding the first connection portion to the tab, welding the second connection portion to the tab, and welding the end cap to the convex portion, it is possible to ensure that the first welded portion and the second welded portion are located on the inner side and the outer side of the third welded portion, respectively, thereby improving the welding efficiency between the current collecting part and the tab and between the end cap and the current collecting part, and improving productivity.

[0011] In some embodiments, the outer surface of the first connection portion and the inner peripheral surface of the convex portion collectively define a first avoidance portion, the first avoidance portion being used to avoid the first welded portion, and the outer surface of the second connection portion and the outer peripheral surface of the convex portion collectively define a second avoidance portion, the second avoidance portion being used to avoid the second welded portion.

[0012] In the above technical proposal, the outer surface of the first connection portion and the inner peripheral surface of the protrusion collectively define a first avoidance portion for avoiding the first welded portion, thereby ensuring good contact between the protrusion and the end cap. The outer surface of the second connection portion and the outer peripheral surface of the protrusion collectively define a second avoidance portion for avoiding the second welded portion, thereby ensuring good contact between the protrusion and the end cap.

[0013] In some embodiments, a recess is formed at a position corresponding to the convex portion of the current collecting part, the recess is recessed along a direction facing the end cap from the inner surface of the main body portion, the convex portion has a first abutment surface for abutting the end cap, the convex portion has a third connection portion located between the first abutment surface and a bottom surface of the recess, and the third connection portion is used for welding to the end cap to form the third weld portion.

[0014] In the above technical solution, the provision of the recess in the current collecting part can reduce the weight of the current collecting part and save materials, while the recess can avoid a third welding part and reduce the impact on the position where the welding between the current collecting part and the tab has already been completed when welding the end cap to the protrusion.

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

[0016] In the above technical solution, the recess is an annular groove, which has a simple structure and is easy to mold and manufacture. When welding the end cap and the current collecting part, the end cap and the protrusion are welded along the circumferential direction of the recess, which can improve the robustness of the end cap and the current collecting part after welding.

[0017] In some embodiments, the protrusion is a ring structure.

[0018] In the above technical proposal, the protrusion has a ring structure, and any position in the circumferential direction of the protrusion can be welded to the end cap to reduce the difficulty of welding. Of course, the end cap and the protrusion can be welded along the circumferential direction of the protrusion to improve the robustness of the end cap and the current collecting component after welding.

[0019] In some embodiments, the end cap has a second abutment surface, the current collecting part abuts against the second abutment surface and is welded to the end cap to form the third weld, the end cap is provided with a third avoidance portion and a fourth avoidance portion recessed along a direction away from the current collecting part from the second abutment surface, the third avoidance portion is used to avoid the first weld, and the fourth avoidance portion is used to avoid the second weld.

[0020] In the above technical solution, the end cap is provided with a third avoidance portion and a fourth avoidance portion recessed in a direction away from the second abutment surface to the current collecting component, the third avoidance portion and the fourth avoidance portion can respectively avoid the first welded portion and the second welded portion, and good contact between the second abutment surface and the current collecting component is ensured. The third avoidance portion and the fourth avoidance portion are installed on the end cap, and the structure of the current collecting component can be simplified.

[0021] In some embodiments, the current collecting component is a tablet structure.

[0022] In the above technical solution, the current collecting part has a tablet structure, which is simple in structure and easy to mold and manufacture.

[0023] In some embodiments, the end cap includes a lid body for covering the opening and a terminal portion protruding from an outer surface of the lid body in a direction away from the electrode assembly, the third weld portion is located on the outer circumferential side of the terminal portion, and in the thickness direction of the end cap, a portion or all of the projection of the terminal portion covers the first weld portion.

[0024] In the above technical solution, the terminal portion of the end cap is used to connect with other components so as to output the electrical energy of the battery cell. The third welded portion is located on the outer periphery of the terminal portion, and the thickness of the portion where the end cap and the current collecting component are welded is relatively thin, ensuring robustness after welding between the end cap and the current collecting component. In the thickness direction of the end cap, a part or the whole of the projection of the terminal portion covers the first welded portion, so that the radial size of the terminal portion is relatively large, which makes it easy to connect with other components and output electrical energy.

[0025] In some embodiments, the end cap has a weld groove formed therein, the end cap forming a fourth connection at a bottom of the weld groove, the fourth connection being adapted for welding to the current collecting piece to form the third weld.

[0026] In the above technical solution, the provision of the welding groove on the end cap reduces the thickness of the portion of the end cap for welding to the current collecting component, increases the depth of the portion of the third weld located in the current collecting component, and improves the robustness after welding between the end cap and the current collecting component; meanwhile, the position of the welding groove is the position where the end cap and the current collecting component are welded together, so that when welding the end cap and the current collecting component, the welding position where the end cap needs to be welded to the current collecting component can be quickly found, and the welding efficiency can be improved.

[0027] In some embodiments, the first weld is annular in structure or includes a plurality of first weld sections spaced apart along a circumferential direction, the first weld sections configured to connect the current collecting piece and the tab.

[0028] In the above technical solution, the first weld has an annular structure, and therefore has good robustness and a relatively large overcurrent area after welding the current collecting part and the tab. The first weld includes a plurality of first weld sections spaced apart along the circumferential direction, and the current collecting part and the tab are welded at a plurality of positions along the circumferential direction to form a first weld section corresponding to each position, which can ensure good robustness after welding the current collecting part and the tab, and can also improve the welding efficiency between the current collecting part and the tab.

[0029] In some embodiments, the second weld is annular in structure or includes a plurality of second weld sections spaced apart along a circumferential direction, the second weld sections configured to connect the current collecting piece and the tab.

[0030] In the above technical solution, the second weld has an annular structure, and therefore has good robustness and a relatively large overcurrent area after welding the current collecting part and the tab. The second weld includes a plurality of second weld sections spaced apart along the circumferential direction, and the current collecting part and the tab are welded at a plurality of positions along the circumferential direction to form a second weld section corresponding to each position, which can ensure good robustness after welding the current collecting part and the tab, and can also improve the welding efficiency between the current collecting part and the tab.

[0031] In some embodiments, the third weld is annular in structure or includes a plurality of third weld sections spaced apart along a circumferential direction, the third weld sections configured to connect the current collecting piece and the end cap.

[0032] In the above technical solution, the third weld has an annular structure, and therefore has good robustness and a relatively large overcurrent area after welding the end cap and the current collecting part. The third weld includes a plurality of third weld sections spaced apart along the circumferential direction, and the end cap and the current collecting part are welded at a plurality of positions along the circumferential direction to form a third weld section corresponding to each position, which can ensure that the end cap and the current collecting part have good robustness after welding, and can improve the welding efficiency between the end cap and the current collecting part.

[0033] According to a second aspect, an embodiment of the present application provides a battery, the battery including a battery cell according to any one of the embodiments of the first aspect, and a housing for housing the battery cell.

[0034] According to a third aspect, an embodiment of the present application provides a power consumer device, said power consumer device comprising a battery according to any one of the embodiments of the second aspect.

[0035] According to a fourth aspect, an embodiment of the present application provides a method for manufacturing a battery cell, the method including the steps of providing a housing having an opening, providing an electrode assembly having a tab, providing an end cap, providing a current collecting piece, welding the current collecting piece and the tab to form a first weld and a second weld, housing the electrode assembly within the housing, placing the end cap over the opening, and welding the end cap and the current collecting piece to form a third weld, where the first weld is located on an inner circumferential side of the third weld and the second weld is located on an outer circumferential side of the third weld.

[0036] According to a fifth aspect, an embodiment of the present application provides a battery cell manufacturing apparatus, the manufacturing apparatus 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 part, and an assembly device used for welding the current collecting part and the tab to form a first weld and a second weld, the assembly device also used for housing the electrode assembly in the housing, the end cap to cover the opening, and the assembly device also used for welding the end cap and the current collecting part to form a third weld, where the first weld is located on an inner circumferential side of the third weld and the second weld is located on an outer circumferential side of the third weld. [Brief description of the drawings]

[0037] In order to more clearly explain the technical solutions of the embodiments of the present application, the following briefly introduces drawings that need to be used in the embodiments. It should be understood that the following drawings only illustrate some embodiments of the present application, and should not be regarded as limiting the scope. Those skilled in the art can also obtain other related drawings based on these drawings without exerting creative efforts. [Figure 1]1 is a structural schematic diagram of a vehicle according to some embodiments of the present application. [Diagram 2] FIG. 1 is a structural schematic diagram of a battery according to some embodiments of the present application. [Diagram 3] 1 is an exploded view of a battery cell according to some embodiments of the present application. [Figure 4] FIG. 1 is a partial schematic diagram of a battery cell according to some embodiments of the present application. [Diagram 5] FIG. 2 is a partial schematic diagram of a battery cell according to some further embodiments of the present application. [Figure 6] FIG. 2 is a distribution diagram of a first weld, a second weld, and a third weld according to some embodiments of the present application. [Figure 7] FIG. 11 is a distribution diagram of a first weld, a second weld, and a third weld according to some further embodiments of the present application. [Figure 8] 1 is a flow chart of a method for manufacturing a battery cell according to some embodiments of the present application. [Figure 9] FIG. 2 is a structural schematic diagram of a battery cell manufacturing equipment according to some embodiments of the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the following will clearly describe the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only some of the embodiments of the present application, and not all of the embodiments. All other embodiments obtained based on the embodiments of the present application without the need for creative efforts by those skilled in the art are all within the scope of protection of the present application.

[0039] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by those skilled in the art in the technical field of this application, and the terms used in the specification of this application are only for describing specific embodiments and are not intended to limit this application, and the terms "include" and "have" and any variations thereof in the specification and claims of this application and the above drawings are intended to cover non-exclusive "include". The terms "first", "second", etc. in the specification and claims of this application or the above drawings are not intended to describe a specific order or subordinate relationship, but are intended to distinguish different objects.

[0040] An "embodiment" referred to in this application means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. Appearances of this phrase in various places throughout the specification are not necessarily all referring to the same embodiment, nor are they mutually exclusive separate or alternative embodiments of other embodiments.

[0041] In the description of this application, it should be explained that unless otherwise clearly defined or limited, the terms "attached", "connected", "connected" and "mounted" should be understood in a broad sense, for example, may be a fixed connection, a detachable connection, or an integral connection, may be a direct connection, may be an indirect connection through an intermediate medium, or may be communication between the insides of two elements. Those skilled in the art can understand the specific meaning of the above terms in the present application according to the specific situation.

[0042] In the embodiments of the present application, the same reference numerals refer to the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the dimensions such as thickness, length and width of various components in the embodiments of the present application shown in the drawings, and the overall dimensions such as thickness, length and width of the integrated device, are merely illustrative and should not be construed as any limitation to the present application.

[0043] The term "plurality" as used herein refers to two or more (including two).

[0044] 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, or a magnesium ion battery, etc., and the embodiments of the present application are not limited thereto. The battery cell may be a cylinder, a flat body, a rectangular body, or other shapes, and the embodiments of the present application are not limited thereto. Generally, the battery cell is divided into three types according to the packaging manner, namely, a prismatic battery cell, a rectangular battery cell, and a pouch battery cell, and the embodiments of the present application are not limited thereto.

[0045] The battery referred to in the embodiments of the present application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, the battery referred to in the present application may include a battery module or a battery pack. The battery generally includes a housing for packaging one or more battery cells. The housing can prevent liquid or other foreign matter from affecting the charging or discharging of the battery cells.

[0046] The battery cell includes an electrode assembly and an electrolyte, and the electrode assembly is composed of a positive electrode plate, a negative electrode plate, and a separator. The battery cell is mainly operated by the movement of metal ions between the positive electrode plate and the negative electrode plate. The positive electrode plate includes a positive electrode collector and a positive electrode active material layer, and the positive electrode active material layer is coated on the surface of the positive electrode collector, and the positive electrode collector without the positive electrode active material layer protrudes from the positive electrode collector already coated with the positive electrode active material layer, and the positive electrode collector without the positive electrode active material layer is the positive electrode tab. Taking a lithium ion battery as an example, the material of the positive electrode collector can be aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganate, etc. The negative electrode plate includes a negative electrode collector and a negative electrode active material layer, the negative electrode active material layer is coated on the surface of the negative electrode collector, the negative electrode collector not coated with the negative electrode active material layer protrudes from the negative electrode collector already coated with the negative electrode active material layer, and the negative electrode collector not coated with the negative electrode active material layer is the negative electrode tab. The material of the negative electrode collector may be copper, and the negative electrode active material may be carbon or silicon, etc. In order to ensure that the electrode assembly does not melt even when a large current flows, the number of positive electrode tabs is multiple and stacked, and the number of negative electrode tabs is multiple and stacked. The material of the separator may be PP (polypropylene) or PE (polyethylene), etc. In addition, the electrode assembly may be a wound type structure or a stacked type structure, and the embodiment of the present application is not limited thereto.

[0047] The development of battery technology requires simultaneous consideration of a wide range of design factors, such as performance parameters such as energy density, cycle life, discharge capacity, and charge / discharge ratio, as well as battery safety.

[0048] The inventor found that for a general battery cell, the battery cell is prone to heat generation during the charging and discharging cycle, which affects the life of the battery cell. The inventor further researched and found that in a battery cell, the end cap and the tab are directly welded to output electrical energy through the end cap. However, due to the structural limitations of the end cap, the welded part (the part where the weld mark is formed by welding the end cap and the tab) formed by welding the end cap and the tab is relatively far away from the center of the electrode assembly, so that the movement path of the electrons of the inner ring part of the electrode assembly to the end cap through the welded part is relatively large, and the movement path of the electrodes of the outer ring part of the electrode assembly to the end cap through the welded part is relatively small, which increases the internal resistance of the battery cell and causes polarization phenomenon, which generates a large amount of heat during charging and discharging of the battery cell, which affects the life of the battery cell.

[0049] In view of this, an embodiment of the present application provides a battery cell, in which an end cap and a tab are connected via a current collecting part to realize an electrical connection between the end cap and the tab, and the current collecting part and the tab are welded to form a first weld and a second weld, and the current collecting part and the end cap are welded to form a third weld, with the first weld located on the inner peripheral side of the third weld and the second weld located on the outer peripheral side of the third weld, so that electrons in the inner ring portion of the electrode assembly can move along a path of the tab, the first weld, the current collecting part, the third weld and the end cap, and electrons in the outer ring portion of the electrode assembly can move along a path of the tab, the second weld, the current collecting part, the third weld and the end cap, thereby making the movement paths of the electrons in the inner ring portion and the electrons in the outer ring portion of the electrode assembly uniform, reducing the internal resistance of the battery cell, and effectively improving the service life of the battery cell.

[0050] The technical solutions described in the embodiments of the present application can be used in batteries and power-consuming devices that use batteries.

[0051] The power consumption devices may be vehicles, mobile phones, portable devices, notebook computers, ships, spacecraft, electric toys and power tools, etc. The vehicles may be fuel oil vehicles, gas vehicles or new energy vehicles, and the new energy vehicles may be pure electric vehicles, hybrid vehicles or range extender vehicles, etc. The spacecraft include airplanes, rockets, space shuttles and spaceships, etc. The electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys and electric plane toys, etc. The electric tools include metal cutting power tools, polishing power tools, assembly power tools and railway power tools, such as electric drills, electric grinders, electric wrenches, electric drivers, electric hammers, hammer drills, concrete vibrators, electric planers, etc. The embodiments of the present application do not place any particular restrictions on the above power consumption devices.

[0052] For convenience of explanation, the following embodiment will be described taking an example in which the power consuming device is a vehicle.

[0053] 1, which is a structural schematic diagram of a vehicle 1000 according to some embodiments of the present application, in which a battery 100 is installed inside the vehicle 1000, and the battery 100 may be installed at the bottom, head or tail of the vehicle 1000. The battery 100 can be used to power the vehicle 1000, for example, the battery 100 can be used as an operating power source for the vehicle 1000.

[0054] The vehicle 1000 may further include a controller 200 and a motor 300, where the controller 200 is used to control the battery 100 to power the motor 300, for example for startup, navigation and operating power consumption needs of the vehicle 1000 during driving.

[0055] In some embodiments of the present application, the battery 100 can be used not only as an operating power source for the vehicle 1000, but also as a driving power source for the vehicle 1000, providing driving power to the vehicle 1000 in place of, or in place of, fuel oil or natural gas.

[0056] Referring to FIG. 2, FIG. 2 is a structural schematic diagram of a battery 100 according to some embodiments of the present application, the battery 100 includes a housing 10 and a battery cell 20, and the housing 10 is used to accommodate the battery cell 20.

[0057] Here, the housing 10 is a member that houses the battery cells 20, and the housing 10 provides a housing space for the battery cells 20, and the housing 10 can adopt various structures. In some embodiments, the housing 10 may include a first portion 11 and a second portion 12, and the first portion 11 and the second portion 12 are placed on each other to define a housing space for storing the battery cells 20. The first portion 11 and the second portion 12 may have various shapes, for example, a rectangular parallelepiped, a cylindrical body, etc. The first portion 11 may be a hollow structure that is open on one side, and the second portion 12 may be a hollow structure that is open on one side, and the housing 10 having the housing space is formed by placing the open side of the second portion 12 on the open side of the first portion 11. The first portion 11 is a hollow structure that is open on one side, and the second portion 12 may be a plate-shaped structure, and the housing 10 having the housing space is formed by placing the open side of the first portion 11 on the open side of the second portion 12. The first part 11 and the second part 12 may achieve a seal via a sealing element, which may be a sealing ring, a sealant, or the like.

[0058] In the battery 100, the battery cell 20 may be one or more. When there are more than one battery cell 20, the battery cells 20 may be connected in series, in parallel, or in series-parallel, and series-parallel connection means that the battery cells 20 are connected in series or in parallel. First, the battery cells 20 are connected in series, in parallel, or in series-parallel to form a battery module, and then the battery modules are connected in series, in parallel, or in series-parallel to be integrated and housed in the housing 10. All the battery cells 20 may be directly connected in series, in parallel, or in series-parallel, and then the entire battery cell module made up of all the battery cells 20 may be housed in the housing 10.

[0059] In some embodiments, the battery 100 may further include a bus bar member, and the multiple battery cells 20 may be electrically connected to each other through the bus bar member to realize a series connection, a parallel connection, or a series-parallel connection of the multiple battery cells 20. The bus bar member may be a metal conductor, such as copper, iron, aluminum, stainless steel, an aluminum alloy, or the like.

[0060] Referring to FIG. 3, FIG. 3 is an exploded view of a battery cell 20 according to some embodiments of the present application, the battery cell 20 including a housing 21, an electrode assembly 22, an end cap 23, and a current collecting component 24.

[0061] The housing 21 is a member for accommodating the electrode assembly 22. The housing 21 may be a hollow structure with an opening at one end, or may be a hollow structure with openings at both opposing ends. When the housing 21 is a hollow structure with an opening at one end, the number of end caps 23 may be one, and this end cap 23 is fitted over the opening of the housing 21 accordingly. When the housing 21 is a hollow structure with openings at both ends, the number of end caps 23 may be two, and the two end caps 23 are fitted over the openings at both ends of the housing 21, respectively. The material of the housing 21 may be various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. The housing 21 may be various shapes, such as a cylinder, a rectangle, etc. Exemplarily, in FIG. 3, the housing 21 is a cylinder, and the housing 21 is a hollow structure with openings at both ends.

[0062] The electrode assembly 22 is a member in which an electrochemical reaction occurs in the battery cell 20. The electrode assembly 22 may include a positive electrode plate, a negative electrode plate, and a separator. The electrode assembly 22 may have a wound structure formed by winding a positive electrode plate, a separator, and a negative electrode plate, or may have a stacked structure formed by stacking a positive electrode plate, a separator, and a negative electrode plate. The electrode assembly 22 may have various shapes, such as a cylinder, a rectangle, and the like. When the housing 21 is a cylinder, the electrode assembly 22 may be a cylinder, and when the housing 21 is a rectangle, the electrode assembly 22 may be a rectangle.

[0063] The positive electrode plate may include a positive electrode current collector and a positive electrode active material layer coated on both opposing sides of the positive electrode current collector. The negative electrode plate may include a negative electrode current collector and a negative electrode active material layer coated on both opposing sides of the negative electrode current collector. The electrode assembly 22 includes a tab 221, which is divided into a positive electrode tab and a negative electrode tab. The positive electrode tab may be a portion of the positive electrode plate that is not coated with a positive electrode active material layer, and the negative electrode tab may be a portion of the negative electrode plate that is not coated with a negative electrode active material layer.

[0064] The end cap 23 is a member that covers the opening of the housing 21 so as to isolate the internal environment of the battery cell 20 from the external environment. The end cap 23 is placed over the opening of the housing 21, and the shape of the end cap 23 may be adapted to the shape of the housing 21. For example, the housing 21 has a rectangular parallelepiped structure, and the end cap 23 has a rectangular plate-like structure that fits the housing 21. Furthermore, for example, as shown in FIG. 3, the housing 21 has a cylindrical structure, and the end cap 23 has a circular plate-like structure that fits the housing 21. The material of the end cap 23 may be various materials, for example, copper, iron, aluminum, steel, aluminum alloy, etc., and the material of the end cap 23 and the material of the housing 21 may be the same or different. In an embodiment in which the battery cell 20 has two end caps 23, the materials of the two end caps 23 may be the same or different.

[0065] A sealant can be used to achieve a sealed connection between the end cap 23 and the housing 21. The sealant can be used to separate the end cap 23 from the housing 21, thereby achieving a seal between the end cap 23 and the housing 21 and insulating the end cap 23 from the housing 21. The sealant can be made of plastic, rubber, or the like.

[0066] The current collecting element 24 is a member that realizes an electrical connection between the end cap 23 and the tab 221. The current collecting element 24 may be one or two. In an embodiment in which only one end cap 23 is installed on the battery cell 20, the current collecting element 24 may be one, and one of the positive and negative tabs is connected to one end cap 23 via one current collecting element 24, and the other is directly connected to the housing 21. In an embodiment in which two end caps 23 are installed on the battery cell 20, the current collecting element 24 may be two, and one of the positive and negative tabs is connected to one end cap 23 via one current collecting element 24, and the other is connected to the other end cap 23 via another current collecting element 24. The current collecting element 24 may be a metal conductor, such as copper, iron, aluminum, steel, aluminum alloy, etc. In an embodiment in which the battery cell 20 has two current collecting elements 24, the materials and structures of the two current collecting elements 24 may be the same or different.

[0067] 4, which is a partial schematic diagram of a battery cell 20 according to 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 collecting part 24. The housing 21 has an opening, the electrode assembly 22 has a tab 221, the electrode assembly 22 is used to be accommodated in the housing 21, the end cap 23 is used to cover the opening, and the current collecting part 24 is used to connect the end cap 23 and the tab 221 to realize an electrical connection between the end cap 23 and the tab 221. Here, the current collecting part 24 and the tab 221 are welded to form a first weld 25 and a second weld 26, and the current collecting part 24 and the end cap 23 are welded to form a third weld 27, the first weld 25 is located on the inner periphery side of the third weld 27, and the second weld 26 is located on the outer periphery side of the third weld 27.

[0068] The current collecting part 24 is used to connect the end cap 23 and the tab 221 to realize an electrical connection between the end cap 23 and the tab 221, and the end cap 23 and the positive electrode tab may be connected via the current collecting part 24, and the end cap 23 and the negative electrode tab may be connected via the current collecting part 24.

[0069] The current collecting part 24 and the tab 221 are welded to form a first welded part 25 and a second welded part 26, and the first welded part 25 and the second welded part 26 are both parts where a weld mark is formed by welding the current collecting part 24 and the tab 221, and the first welded part 25 and the second welded part 26 both play a role of connecting the current collecting part 24 and the tab 221. The current collecting part 24 and the tab 221 can be welded by various welding methods, for example, the current collecting part 24 and the tab 221 can be welded by adopting a penetration welding method, and the current collecting part 24 and the tab 221 can be welded on the outside of the current collecting part 24 (the side away from the tab of the current collecting part 24) so ​​as to weld the current collecting part 24 and the tab 221.

[0070] The current collecting part 24 and the end cap 23 are welded to form a third weld 27, where a weld mark is formed by welding the current collecting part 24 and the tab 221, and the third weld 27 serves to connect the current collecting part 24 and the end cap 23. The current collecting part 24 and the end cap 23 can be welded by various welding methods, for example, the current collecting part 24 and the end cap 23 can be welded by a full penetration welding method, and the outer side of the end cap 23 (the side of the end cap 23 away from the current collecting part) can be welded to the end cap 23 and the current collecting part 24.

[0071] The first welded portion 25 is located on the inner periphery side of the third welded portion 27, i.e., the third welded portion 27 is located outside the first welded portion 25 in a direction perpendicular to the thickness direction Z of the end cap 23, and the third welded portion 27 may be understood to be located other than the outer periphery surface of the first welded portion 25. The second welded portion 26 is located on the outer periphery side of the third welded portion 27, i.e., the second welded portion 26 is located outside the third welded portion 27 in a direction perpendicular to the thickness direction Z of the end cap 23, and the second welded portion 26 may be understood to be located other than the outer periphery surface of the third welded portion 27. In other words, in the direction perpendicular to the thickness direction Z of the end cap 23, the first welded portion 25, the third welded portion 27, and the second welded portion 26 are arranged in order from the inside to the outside. The first welded portion 25, the second welded portion 26, and the third welded portion 27 may be arranged coaxially or eccentrically. It should be explained that the first welded portion 25 is located on the inner circumferential side of the third welded portion 27, and does not limit the positional relationship between the first welded portion 25 and the third welded portion 27 in the thickness direction Z of the end cap 23, but limits the inside-outside relationship between the first welded portion 25 and the third welded portion 27, that is, the first welded portion 25 and the third welded portion 27 may or may not be spaced apart in the thickness direction Z of the end cap 23. Similarly, the second welded portion 26 is located on the outer circumferential side of the third welded portion 27, and does not limit the positional relationship between the second welded portion 26 and the third welded portion 27 in the thickness direction Z of the end cap 23, but limits the inside-outside relationship between the second welded portion 26 and the third welded portion 27, that is, the second welded portion 26 and the third welded portion 27 may or may not be spaced apart in the thickness direction Z of the end cap 23.

[0072] The first weld 25 may be a closed structure extending along the circumferential direction and connected to the end, for example, the first weld 25 is an annular structure. The first weld 25 may be a non-closed structure extending along the circumferential direction and spaced apart, for example, the first weld 25 is a semi-annular structure. Of course, the first weld 25 may be divided into a plurality of sections distributed at intervals along the circumferential direction. The second weld 26 may be a closed structure extending along the circumferential direction and connected to the end, for example, the second weld 26 is an annular structure. The second weld 26 may be a non-closed structure extending along the circumferential direction and spaced apart, for example, the second weld 26 is a semi-annular structure. Of course, the second weld 26 may be divided into a plurality of sections distributed at intervals along the circumferential direction. The third weld 27 may be a closed structure extending along the circumferential direction and connected to the end, for example, the third weld 27 is an annular structure. The third weld 27 may be a non-closed structure extending along the circumferential direction and spaced apart from the end, for example, the third weld 27 is a semi-annular structure. Of course, the third weld 27 may be divided into multiple sections distributed at intervals along the circumferential direction.

[0073] The second welded portion 26 located on the outer circumferential side of the third welded portion 27 may have one turn or multiple turns. The first welded portion 25 located on the inner circumferential side of the third welded portion 27 may have one turn or multiple turns.

[0074] In the battery cell 20, the tab 221 and the end cap 23 are connected via the current collecting part 24, and the current collecting part 24 and the tab 221 are welded to form a first welded part 25 and a second welded part 26, and the current collecting part 24 and the end cap 23 are welded to form a third welded part 27. The first welded part 25 and the second welded part 26 are located on the inner periphery side and the outer periphery side of the third welded part 27, respectively. Thus, the electrons in the inner ring portion of the electrode assembly 22 are welded through the tab 221, the first welded part 25, the current collecting part 24, the third welded part 27, and the tab 221. The electrons in the outer ring portion of the electrode assembly 22 can move along a path through the tab 221, the second welded portion 26, the current collecting part 24, the third welded portion 27 and the end cap 23, and the paths of movement of the electrons in the inner ring portion and the outer ring portion of the electrode assembly 22 are approximately identical to each other, so that the paths of movement of the electrons in the inner ring portion and the electrons in the outer ring portion of the electrode assembly 22 are uniform, the internal resistance of the battery cell 20 is reduced, and the service life of the battery cell 20 is effectively improved.

[0075] In addition, since the current collecting part 24 and the tab 221 are connected via the first welded part 25 and the second welded part 26, both the first welded part 25 and the second welded part 26 are capable of overcurrent, increasing the overcurrent capacity and meeting the demand for large magnification overcurrent. The first welded part 25 and the second welded part 26 are located on the inner periphery and outer periphery of the third welded part 27, respectively, so that the first welded part 25, the second welded part 26, and the third welded part 27 do not overlap in the thickness direction Z of the end cap 23, reducing the risk of weak welding between the end cap 23 and the current collecting part 24 due to overlapping of the third welded part 27 with the first welded part 25 or the second welded part 26.

[0076] In a typical battery cell 20, the weld formed by welding the current collecting part 24 to the tab 221 and the weld formed by welding the end cap 23 to the current collecting part 24 are basically located on the same circumference. In order to prevent the weld formed by welding the current collecting part 24 to the tab 221 and the weld formed by welding the end cap 23 to the current collecting part 24 from overlapping in the thickness direction Z of the end cap 23, when welding the end cap 23 to the current collecting part 24, it is necessary to find a welding position to ensure that the weld formed by welding the end cap 23 to the current collecting part 24 and the weld formed by welding the current collecting part 24 to the tab 221 are misaligned in the circumferential direction, and the welding efficiency is relatively low.

[0077] On the other hand, in the battery cell 20 according to the embodiment of the present application, the first weld 25 is located on the inner periphery of the third weld 27, and the second weld 26 is located on the outer periphery of the third weld 27. Therefore, in the actual welding process, the current collecting part 24 and the tab 221 are welded to form the first weld 25 and the second weld 26, and then the end cap 23 and the current collecting part 24 are welded in the region between the first weld 25 and the second weld 26, thereby forming the third weld 27 located on the outer periphery of the first weld 25 and on the inner periphery of the second weld 26. This improves the welding efficiency between the end cap 23 and the current collecting part 24, and further improves production efficiency.

[0078] 4 , in some embodiments, the current collecting part 24 includes a body portion 241 and a protruding portion 242. The body portion 241 is used to abut and weld to the tab 221 to form the first welded portion 25 and the second welded portion 26. The protruding portion 242 protrudes from the outer surface of the body portion 241 in a direction facing the end cap 23, and the protruding portion 242 is used to abut and weld to the end cap 23 to form the third welded portion 27.

[0079] The outer surface of the main body portion 241 refers to the surface of the main body portion 241 that is away from the tab 221. Of course, the main body portion 241 also has an inner surface, and the inner surface of the main body portion 241 refers to the surface that is in contact with the tab 221. The main body portion 241 may have a plate-like structure.

[0080] The convex portion 242 protrudes from the outer surface of the main body portion 241 in a 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 main body portion 241 in a direction approaching the end cap 23.

[0081] In this embodiment, the main body portion 241 is the part that welds the current collecting part 24 and the tab 221, and the convex portion 242 is the part that welds the current collecting part 24 and the end cap 23. The convex portion 242 of the current collecting part 24 protrudes from the outer surface of the main body portion 241 in the direction facing the end cap 23, and when the convex portion 242 abuts the end cap 23, good contact can be ensured, making it easier to weld the end cap 23 and the current collecting part 24 together.

[0082] 4 , in some embodiments, the main body portion 241 includes a first connecting portion 2411 and a second connecting portion 2412. The first connecting portion 2411 is connected to the protrusion 242 and is located on the inner circumferential side of the protrusion 242, and the first connecting portion 2411 is used to abut and weld with the tab 221 to form the first welded portion 25, and the second connecting portion 2412 is connected to the protrusion 242 and is located on the outer circumferential side of the protrusion 242, and the second connecting portion 2412 is used to abut and weld with the tab 221 to form the second welded portion 26.

[0083] The first connection portion 2411 is connected to the protrusion 242 and is located on the inner periphery side of the protrusion 242, i.e., the first connection portion 2411 and the protrusion 242 are connected, and the first connection portion 2411 is located inside the protrusion 242 in the direction perpendicular to the thickness direction Z of the end cap 23. The second connection portion 2412 is connected to the protrusion 242 and is located on the outer periphery side of the protrusion 242, i.e., the second connection portion 2412 and the protrusion 242 are connected, and the second connection portion 2412 is located outside the protrusion 242 in the direction perpendicular to the thickness direction Z of the end cap 23.

[0084] The first connecting portion 2411, the protruding portion 242, and the second connecting portion 2412 may have an integrally molded structure. The first connecting portion 2411 and the second connecting portion 2412 may each have a plate-like structure.

[0085] In this embodiment, the first connection portion 2411 of the main body portion 241 is located on the inner circumferential side of the protrusion 242, and the second connection portion 2412 of the main body portion 241 is located on the outer circumferential side of the protrusion 242. The first connection portion 2411 and the second connection portion 2412 are partitioned by the protrusion 242, so that three clearly separated welding regions are formed over the entire current collecting part 24. The three welding regions are respectively the first connection portion 2411, the protrusion 242, and the second connection portion 2412 of the current collecting part 24. By welding the first connection portion 2411 to the tab 221, welding the second connection portion 2412 to the tab 221, and welding the end cap 23 to the convex portion 242, it is possible to ensure that the first welded portion 25 and the second welded portion 26 are located on the inner and outer circumferential sides of the third welded portion 27, respectively, thereby improving the welding efficiency between the current collecting part 24 and the tab 221, and between the end cap 23 and the current collecting part 24, and thereby improving productivity.

[0086] In some embodiments, still referring to FIG. 4 , the outer surface of the first connection portion 2411 and the inner surface of the convex portion 242 collectively define a first avoidance portion 243, which is used to avoid the first weld portion 25, and the outer surface of the second connection portion 2412 and the outer surface of the convex portion 242 collectively define a second avoidance portion 244, which is used to avoid the second weld portion 26.

[0087] The outer surface of the first connecting portion 2411 refers to the surface of the first connecting portion 2411 that is away from the tab 221. The outer surface of the second connecting portion 2412 refers to the surface of the second connecting portion 2412 that is away from the tab 221. The protrusion 242 has a first abutment surface 2421 for abutting against the end cap 23, the inner circumferential surface of the protrusion 242 is a surface that is connected between the first abutment surface 2421 of the protrusion 242 and the outer surface of the first connecting portion 2411, and the outer circumferential surface of the protrusion 242 is a surface that is connected between the first abutment surface 2421 of the protrusion 242 and the outer surface of the second connecting portion 2412.

[0088] Since the first avoidance portion 243 serves to avoid the first welded portion 25, at least a portion of the first welded portion 25 is accommodated within the first avoidance portion 243, and the first avoidance portion 243 may have a concave groove structure that is recessed in a direction away from the first abutment surface 2421 of the convex portion 242 and away from the end cap 23. Since the second avoidance portion 244 serves to avoid the second welded portion 26, at least a portion of the second welded portion 26 is accommodated within the second avoidance portion 244, and the second avoidance portion 244 may have a concave groove structure that is recessed in a direction away from the first abutment surface 2421 of the convex portion 242 and away from the end cap 23.

[0089] Because the end cap 23 abuts against the convex portion 242, the end cap 23 seals the first avoidance portion 243, and the portion of the first welded portion 25 located within the first avoidance portion 243 is restricted within the first avoidance portion 243 by the end cap 23. Even if a part of the first welded portion 25 falls off, it will not fall into the interior of the battery cell 20, and there is less risk of the first welded portion 25 falling off locally and falling into the interior of the battery cell 20, which would affect the performance of the battery cell 20.

[0090] The outer surface of the first connecting portion 2411 and the inner peripheral surface of the convex portion 242 collectively define a first avoidance portion 243 for avoiding the first welded portion 25, thereby ensuring good contact between the convex portion 242 and the end cap 23, and improving robustness after welding between the end cap 23 and the current collecting part 24. The outer surface of the second connecting portion 2412 and the outer peripheral surface of the convex portion 242 collectively define a second avoidance portion 244 for avoiding the second welded portion 26, thereby ensuring good contact between the convex portion 242 and the end cap 23, and improving robustness after welding between the end cap 23 and the current collecting part 24.

[0091] 4 , in some embodiments, a recess 245 is formed at a position corresponding to the protrusion 242 of the current collecting part 24, and the recess 245 is recessed along a direction facing the end cap 23 from the inner surface of the body part 241. The protrusion 242 has a first abutment surface 2421 for abutting against the end cap 23, and the protrusion 242 has a third connection portion 2422 located between the first abutment surface 2421 and a bottom surface of the recess 245, and the third connection portion 2422 is used for welding to the end cap 23 to form a third welded portion 27.

[0092] The bottom surface of the recess 245 is a surface connected to the side surface of the recess 245, and the bottom surface of the recess 245 faces the tab 221 and is spaced apart from the tab 221. The protrusion 242 has a third connecting portion 2422 located between the first abutment surface 2421 and the bottom surface of the recess 245, and the third connecting portion 2422 is a portion of the protrusion 242 located between the first abutment surface 2421 and the bottom surface of the recess 245. The recess 245 may be an annular groove, which has a simple structure and is easy to mold and manufacture.

[0093] 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 have a plate-like structure, similar to the first connecting portion 2411 and the second connecting portion 2412.

[0094] The current collecting piece 24 may be formed from a single sheet of plate material by pressing, whereby one side of the plate material is pressed to form a recess 245 and the other side of the plate material is pressed to form a protrusion 242 at a position corresponding to the recess 245.

[0095] In this embodiment, the provision of the recess 245 in the current collecting part 24 can reduce the weight of the current collecting part 24 and save material, while the recess 245 can avoid the third welding part 27 and reduce the impact on the position where welding between the current collecting part 24 and the tab 221 has already been completed when welding the end cap 23 and the protrusion 242.

[0096] In some embodiments, protrusion 242 is a ring-shaped structure.

[0097] In an 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 annular structure or may be circular structure.

[0098] Since the protrusion 242 has an annular structure, any position in the circumferential direction of the protrusion 242 can be welded to the end cap 23, thereby reducing the difficulty of welding. 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 robustness of the end cap 23 and the current collecting part 24 after welding.

[0099] In some embodiments, referring to Fig. 5, Fig. 5 is a partial schematic diagram of a battery cell 20 according to some other embodiments of the present application, in which the end cap 23 has a second abutment surface 231, and the current collecting part 24 abuts against the second abutment surface 231 and is welded to the end cap 23 to form a third welded part 27. The end cap 23 is provided with a third avoidance portion 232 and a fourth avoidance portion 233 recessed along a direction away from the current collecting part 24 from the second abutment surface 231, and the third avoidance portion 232 is used to avoid the first welded part 25, and the fourth avoidance portion 233 is used to avoid the second welded part 26.

[0100] Since the third avoidance portion 232 serves to avoid the first welded portion 25, at least a portion of the first welded portion 25 is accommodated within the third avoidance portion 232, and the third avoidance portion 232 may have a concave groove structure that is recessed in a direction away from the second abutment surface 231 and away from the current collecting part 24. Since the fourth avoidance portion 233 serves to avoid the second welded portion 26, at least a portion of the second welded portion 26 is accommodated within the fourth avoidance portion 233, and the fourth avoidance portion 233 may have a concave groove structure that is recessed in a direction away from the second abutment surface 231 and away from the current collecting part 24.

[0101] It should be noted that when two end caps 23 and two current collecting parts 24 are installed on 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 parts 24 may be the same or different. For example, one end cap 23 and one current collecting part 24 adopt the structure shown in Fig. 5 (avoiding parts for avoiding the first welded part 25 and the second welded part 26 are installed on the end cap 23), and another end cap 23 and another current collecting part 24 adopt the structure shown in Fig. 4 (avoiding parts for avoiding the first welded part 25 and the second welded part 26 are installed on the current collecting part 24).

[0102] End cap 23 is provided with third avoidance portion 232 and fourth avoidance portion 233 recessed in a direction away from second abutment surface 231 toward current collecting part 24, so that third avoidance portion 232 and fourth avoidance portion 233 can avoid first welded portion 25 and second welded portion 26, respectively, ensuring good contact between second abutment surface 231 and current collecting part 24. Third avoidance portion 232 and fourth avoidance portion 233 are provided in end cap 23, and the structure of current collecting part 24 can be simplified.

[0103] In some embodiments, with continued reference to FIG. 5, current collecting element 24 is a tablet structure.

[0104] The current collecting element 24 has a tablet structure, that is, the current collecting element 24 has a plate structure with a uniform thickness. When the outer surface and the inner surface of the current collecting element 24 are arranged parallel to each other, the thickness of the current collecting element 24 can be made almost uniform.

[0105] In this embodiment, the current collecting part 24 has a tablet structure, which is simple in structure and easy to mold and manufacture.

[0106] It should be noted that in other embodiments, when the end cap 23 is provided with a third avoidance portion 232 and a fourth avoidance portion 233 for avoiding the first welded portion 25 and the second welded portion 26, respectively, the current collecting part 24 is provided with a first avoidance portion 243 and a second avoidance portion 244 for avoiding the first welded portion 25 and the second welded portion 26, respectively, thereby making it possible to increase the avoidance space for avoiding the first welded portion 25 and the second welded portion 26 for the entire structure.

[0107] 4 and 5 , in some embodiments, the end cap 23 includes a lid body 234 and a terminal portion 235, the lid body 234 is used to cover the opening of the housing 21, and the terminal portion 235 protrudes from the outer surface of the lid body 234 in a direction away from the electrode assembly 22. The third welding portion 27 is located on the outer periphery of the terminal portion 235, and a part or all of the projection of the terminal portion 235 in the thickness direction Z of the end cap 23 covers the first welding portion 25.

[0108] The terminal portion 235 is a portion of the end cap 23 for outputting electrical energy from the battery cell 20, and is used for connecting to other members, for example, the terminal portion 235 is connected to a bus bar member. The lid body 234 is a portion of the end cap 23 for connecting to the housing 21 and for covering an opening of the housing 21. The terminal portion 235 and the lid body 234 may be an integrally molded structure, or may be a separate structure connected to each other, for example, the terminal portion 235 and the lid body 234 are welded to each other. The terminal portion 235 may be located at the center of the lid body 234. In an embodiment in which the electrode assembly 22 has a cylindrical structure, the tab 221 may be an annular structure, and the terminal portion 235 may be disposed coaxially with the tab 221.

[0109] In this embodiment, the third welded portion 27 is located on the outer periphery of the terminal portion 235, and the thickness of the portion where the end cap 23 and the current collecting part 24 are welded is relatively thin, ensuring robustness after welding between the end cap 23 and the current collecting part 24. In the thickness direction Z of the end cap 23, a part or all of the projection of the terminal portion 235 covers the first welded portion 25, and therefore the radial size of the terminal portion 235 is relatively large, making it easy to connect to other members (e.g., bus bar members) and outputting electrical energy.

[0110] For a general battery cell 20, direct welding of the end cap 23 and the tab 221 may be adopted to realize electrical connection between the end cap 23 and the tab 221. However, due to the large thickness of the end cap 23 in the area of ​​the terminal portion 235, it is not possible to weld the tab 221 to the area of ​​the end cap 23 located at the terminal portion 235. The end cap 23 can only form a weld by welding the lid body 234 and the tab 221, and the weld formed by welding the lid body 234 and the tab 221 can only be located on the outer periphery of the terminal portion 235, so that the weld is far away from the center of the electrode assembly 22, and the internal resistance of the battery cell 20 is increased. However, in this embodiment, since the end cap 23 and the tab 221 are connected via the current collecting part 24, the position of the first weld 25 formed by welding the current collecting part 24 and the tab 221 is no longer restricted by the structure of the end cap 23. In the thickness direction Z of the end cap 23, part or all of the projection of the terminal portion 235 covers the first weld 25, so that the first weld 25 can be brought closer to the center position of the electrode assembly 22, which is advantageous for reducing the internal resistance of the battery cell 20.

[0111] In some embodiments, with continued reference to FIGS. 4 and 5 , the end cap 23 is provided with a weld groove 236, and the end cap 23 forms a fourth connection portion 237 at the bottom of the weld groove 236, which is used for welding to the current collecting piece 24 to form the third weld portion 27.

[0112] The fourth connection portion 237 is a portion where the end cap 23 and the current collecting part 24 are welded together, and the portion between the bottom surface of the welding groove 236 and the surface of the end cap 23 that abuts against the current collecting part 24 is the fourth connection portion 237. As shown in FIG. 5, for example, the surface of the end cap 23 that abuts against the current collecting part 24 is the second abutment surface 231, and the portion of the end cap 23 between the bottom surface of the welding groove 236 and the second abutment surface 231 is the fourth connection portion 237. For example, the welding between the end cap 23 and the current collecting part 24 is achieved by using a penetration welding method, and the thickness of the fourth connection portion 237 is relatively thin compared to the thickness of other parts of the end cap 23, so that the end cap 23 can be easily penetrated during welding, and the end cap 23 and the current collecting part 24 are connected together.

[0113] In an embodiment in which the end cap 23 includes a lid body 234 and a terminal portion 235 , the weld groove 236 may be recessed from the outer surface of the lid body 234 along a direction facing the electrode assembly 22 .

[0114] The provision of the welding groove 236 on the end cap 23 reduces the thickness of the portion of the end cap 23 for welding to the current collecting part 24, increases the depth of the portion of the third weld 27 located within the current collecting part 24, and improves the robustness after welding between the end cap 23 and the current collecting part 24. Meanwhile, the position of the welding groove 236 is the position where the end cap 23 and the current collecting part 24 are welded together. When welding the end cap 23 and the current collecting part 24 together, the welding position where the end cap 23 needs to be welded to the current collecting part 24 can be quickly found, and the welding efficiency can be improved.

[0115] In some embodiments, referring to FIG. 6, FIG. 6 is a distribution diagram of the first weld 25, the second weld 26, and the third weld 27 according to some embodiments of the present application, in which the first weld 25 has an annular structure, and therefore has good robustness and a relatively large overcurrent area after welding between the current collecting part 24 and the tab 221.

[0116] In some other embodiments, refer to Fig. 7, which is a distribution map of the first weld 25, the second weld 26, and the third weld 27 according to some other embodiments of the present application, in which the first weld 25 includes a plurality of first weld sections 251 spaced apart along the circumferential direction, and the first weld sections 251 are configured to connect the current collecting part 24 and the tab 221. The current collecting part 24 and the tab 221 are welded at a plurality of positions in the circumferential direction to form one first weld section 251 corresponding to each position, which can ensure good robustness after welding between the current collecting part 24 and the tab 221, and can also improve the welding efficiency between the current collecting part 24 and the tab 221.

[0117] In some embodiments, with continued reference to FIG. 6, the second weld 26 has an annular structure, so that after welding the current collecting part 24 and the tab 221, it has good robustness and a relatively large overcurrent area.

[0118] 7 , in some other embodiments, the second welded portion 26 includes a plurality of second welded sections 261 spaced apart along the circumferential direction, and the second welded sections 261 are configured to connect the current collecting part 24 and the tab 221. The current collecting part 24 and the tab 221 are welded at a plurality of positions along the circumferential direction to form one second welded section 261 corresponding to each position, which can ensure good robustness after welding between the current collecting part 24 and the tab 221, and can also improve the welding efficiency between the current collecting part 24 and the tab 221.

[0119] In some embodiments, still referring to FIG. 6, the third weld 27 has an annular structure, so that after welding the end cap 23 and the current collecting piece 24 together, it has good robustness and a relatively large overcurrent area.

[0120] Illustratively, in the thickness direction Z (not shown in FIG. 6) of the end cap 23, the projection of the third weld 27 divides the tab 221 (not shown in FIG. 6) into two parts, the areas of which are equal; in other words, the area of ​​the part of the tab 221 located on the inner side of the third weld 27 is equal to the area of ​​the part of the tab 221 located on the outer side of the third weld 27.

[0121] 7 , in some other embodiments, the third weld 27 includes a plurality of third weld sections 271 spaced apart along the circumferential direction, and the third weld sections 271 are configured to connect the current collecting part 24 and the end cap 23. The end cap 23 and the current collecting part 24 are welded at a plurality of positions along the circumferential direction to form one third weld section 271 corresponding to each position, which can ensure good robustness after welding between the end cap 23 and the current collecting part 24, and can also improve the welding efficiency between the end cap 23 and the current collecting part 24.

[0122] An embodiment of the present application provides a battery 100, which includes a housing 10 for housing a battery cell 20, and the battery cell 20 according to any one of the embodiments described above.

[0123] An embodiment of the present application provides a power consumer device, including a battery 100 according to any one of the embodiments described above.

[0124] The power consuming device may be any one of the battery 100 applications described above.

[0125] Furthermore, referring to FIG. 3 , an embodiment of the present application further provides a cylindrical battery, comprising a housing 21, an electrode assembly 22, two end caps 23, and two current collecting parts 24, in which the housing 21 has two openings arranged opposite to each other, the two end caps 23 are used to cover the two openings, respectively, the electrode assembly 22 is used to be accommodated in the housing 21, the electrode assembly 22 has two tabs 221 arranged opposite to each other and having opposite polarities, one tab 221 is electrically connected to one end cap 23 via one current collecting part 24, and another tab 221 is electrically connected to the other end cap 23 via the other current collecting part 24. 4 and 5, the current collecting part 24 and the tab 221 are welded to form a first weld 25 and a second weld 26, and the current collecting part 24 and the end cap 23 are welded to form a third weld 27, with the first weld 25 located on the inner periphery side of the third weld 27 and the second weld 26 located on the outer periphery side of the third weld 27. A cylindrical battery with such a structure has a relatively small internal resistance and a longer service life.

[0126] An embodiment of the present application provides a method for manufacturing a battery cell 20. Referring to FIG. 8, FIG. 8 is a flow chart of a method for manufacturing a battery cell 20 according to some embodiments of the present application, the method for manufacturing the battery cell 20 includes: S100 providing a housing 21 having an opening; providing an electrode assembly 22 having a tab 221; S300 providing the end cap 23; S400 providing a current collecting component 24; welding the current collecting member 24 and the tab 221 of the electrode assembly 22 to form a first weld 25 and a second weld 26 (S500); S600 for housing the electrode assembly 22 in the housing 21; S700: placing the end cap 23 over the opening of the housing 21; S800 welding the end cap 23 and the current collecting piece 24 to form a third weld 27.

[0127] Here, the first welded portion 25 is located on the inner peripheral side of the third welded portion 27 , and the second welded portion 26 is located on the outer peripheral side of the third welded portion 27 .

[0128] In the above method, there is no restriction on the order of steps S100, S200, S300, and S400. For example, step S400 may be performed first, then step S300, then step S200, and then step S100.

[0129] It should be noted that the relevant structures of the battery cell 20 manufactured by the manufacturing methods according to the above embodiments may refer to the battery cell 20 according to the above embodiments, and will not be further described here.

[0130] In addition, an embodiment of the present application provides a manufacturing apparatus 2000 for a battery cell 20. Referring to FIG. 9, FIG. 9 is a structural schematic diagram of the manufacturing apparatus 2000 for a battery cell 20 according to some embodiments of the present application, in which 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 assembly device 2500. The first providing device 2100 is used to provide a housing 21 and has an opening. The second providing device 2200 is used to provide an electrode assembly 22, and the electrode assembly 22 has a tab 221. The third providing device 2300 is used to provide an end cap 23, and the fourth providing device 2400 is used to provide a current collecting part 24. The assembling device 2500 is used to weld the current collecting part 24 and the tab 221 to form the first welded part 25 and the second welded part 26, the assembling device 2500 is also used to house the electrode assembly 22 in the housing 21, and the assembling device 2500 is also used to cover the opening with the end cap 23. The assembling device 2500 is also used to weld the end cap 23 and the current collecting part 24 to form the third welded part 27. Here, the first welded part 25 is located on the inner periphery side of the third welded part 27, and the second welded part 26 is located on the outer periphery side of the third welded part 27.

[0131] It should be noted that the relevant structures of the battery cell 20 manufactured by the manufacturing equipment 2000 according to the above embodiment may refer to the battery cell 20 according to the above embodiments, and will not be further described here.

[0132] It should be noted that, unless there is a conflict, the embodiments and features in the embodiments in the present application can be combined with each other.

[0133] The above examples are only intended to explain the technical solution of the present application, and are not intended to limit the present application. Those skilled in the art may make various modifications and variations to the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application. [Explanation of symbols]

[0134] 10. Chassis 11 First Part 12 Second Part 20 Battery Cells 21 Housing 22 Electrode Assembly 221 tabs 23 End cap 231 Second abutment surface 232 Third Evasion 233 The Fourth Evasion 234 Lid body 235 Terminal section 236 Welding Groove 237 Fourth Connection 24 Current collector 241 Main body 2411 First Connection 2412 Second Connection 242 Convex 2421 First contact surface 2422 Third Connection 243 First Evasion 244 Second Evasion 245 Recess 25 First Weld 251 First Welding Section 26 Second Weld 261 Second Welding Section 27 Third Weld 271 Third Welding Section 100 batteries 200 Controller 300 Motor 1000 vehicles 2000 Manufacturing equipment 2100 First provision device 2200 Secondary provider 2300 Third provision device 2400 Fourth Provider 2500 Assembly Equipment Z thickness direction

Claims

1. A battery cell, a housing having an opening; an electrode assembly having a tab for receipt within said housing; an end cap for covering the opening; a current collecting part for connecting the end cap and the tab so as to realize an electrical connection between the end cap and the tab; Here, the current collecting part and the tab are welded to form a first weld and a second weld, and the current collecting part and the end cap are welded to form a third weld, the first weld is located on the inner circumferential side of the third weld and the second weld is located on the outer circumferential side of the third weld, and the first weld, the second weld and the third weld do not overlap in the thickness direction of the end cap, The current collecting component is a body portion for abutting and welding to the tab to form the first weld and the second weld; a protrusion protruding from an outer surface of the body portion along a direction facing the end cap and adapted to abut against and weld to the end cap to form the third weld; a recess is formed at a position of the current collecting part corresponding to the protrusion, the recess being recessed along a direction from an inner surface of the main body part toward the end cap, the protrusion has a first abutment surface for abutting against an end cap, the protrusion has a third connection portion located between the first abutment surface and a bottom surface of the recess, the third connection portion being used for welding to the end cap to form the third welded portion; The battery cell, wherein the recess is an annular groove.

2. The main body portion is a first connection portion that is connected to the protrusion and is located on an inner peripheral side of the protrusion, the first connection portion being adapted to abut and weld to the tab so as to form a first weld; 2. The battery cell according to claim 1, further comprising: a second connection portion connected to the protrusion and located on an outer circumferential side of the protrusion, the second connection portion being adapted to abut and weld to the tab to form the second welded portion.

3. an outer surface of the first connection portion and an inner circumferential surface of the protrusion jointly define a first avoidance portion for avoiding the first welded portion; The battery cell according to claim 2 , wherein an outer surface of the second connection portion and an outer circumferential surface of the protrusion collectively define a second avoidance portion for avoiding the second welded portion.

4. The battery cell according to any one of claims 1 to 3, wherein the protrusion has a ring structure.

5. the end cap has a second abutment surface, the current collecting part abuts against the second abutment surface and is welded to the end cap to form the third weld; 2. The battery cell of claim 1, wherein the end cap has a third avoidance portion and a fourth avoidance portion recessed in a direction away from the second abutment surface and away from the current collecting component, the third avoidance portion being used to avoid the first welded portion, and the fourth avoidance portion being used to avoid the second welded portion.

6. The battery cell according to claim 5 , wherein the current collecting component has a tablet structure.

7. A battery cell, a housing having an opening; an electrode assembly having a tab for receipt within said housing; an end cap for covering the opening; a current collecting part for connecting the end cap and the tab so as to realize an electrical connection between the end cap and the tab; Here, the current collecting part and the tab are welded to form a first weld and a second weld, and the current collecting part and the end cap are welded to form a third weld, the first weld is located on the inner circumferential side of the third weld and the second weld is located on the outer circumferential side of the third weld, and the first weld, the second weld and the third weld do not overlap in the thickness direction of the end cap, The end cap is A lid body for covering the opening; a terminal portion protruding from an outer surface of the lid body in a direction away from the electrode assembly, the third welded portion is located on an outer circumferential side of the terminal portion, and in a thickness direction of the end cap, a part or all of a projection of the terminal portion covers the first welded portion.

8. The battery cell according to any one of claims 1 to 7, wherein the end cap has a weld groove, the end cap forms a fourth connection portion at a bottom of the weld groove, and the fourth connection portion is used for welding to the current collecting component to form the third weld portion.

9. 9. The battery cell according to claim 1, wherein the first welded portion has an annular structure or includes a plurality of first welded sections distributed at intervals along a circumferential direction, and the first welded sections are configured to connect the current collecting component and the tab.

10. The battery cell according to any one of claims 1 to 9, wherein the second welded portion has an annular structure or includes a plurality of second welded sections distributed at intervals along a circumferential direction, and the second welded sections are configured to connect the current collecting component and the tab.

11. The battery cell according to any one of claims 1 to 10, wherein the third welded portion has an annular structure or includes a plurality of third welded sections distributed at intervals along a circumferential direction, and the third welded sections are configured to connect the current collecting component and the end cap.

12. A battery, A battery cell according to any one of claims 1 to 11, a housing for housing the battery cell.

13. 13. A power consuming device comprising the battery of claim 12.

14. A method for manufacturing a battery cell, comprising: Providing a housing having an opening; Providing an electrode assembly having a tab; providing an end cap; Providing a current collecting component; welding the current collecting piece and the tab to form a first weld and a second weld; housing the electrode assembly within the housing; placing the end cap over the opening; and welding the end cap and the current collecting piece to form a third weld. Here, the first welded portion is located on the inner circumferential side of the third welded portion, the second welded portion is located on the outer circumferential side of the third welded portion, the first welded portion, the second welded portion, and the third welded portion do not overlap in a thickness direction of the end cap, The current collecting component is a body portion for abutting and welding to the tab to form the first weld and the second weld; a protrusion protruding from an outer surface of the body portion along a direction facing the end cap and adapted to abut against and weld to the end cap to form the third weld; a recess is formed at a position of the current collecting part corresponding to the protrusion, the recess being recessed along a direction from an inner surface of the main body part toward the end cap, the protrusion has a first abutment surface for abutting against an end cap, the protrusion has a third connection portion located between the first abutment surface and a bottom surface of the recess, the third connection portion being used for welding to the end cap to form the third welded portion; The method for manufacturing a battery cell, wherein the recess is an annular groove.

15. A battery cell manufacturing device comprising: a first providing device for providing a housing having an opening; a second presentation device for presenting an electrode assembly having a tab; a third application device for applying an end cap; a fourth presenting device for presenting a current collecting piece; an assembly device that is used to weld the current collecting piece and the tab to form a first weld and a second weld, that is also used to house the electrode assembly within the housing, that is also used to place the end cap over the opening, and that is also used to weld the end cap and the current collecting piece to form a third weld; Here, the first welded portion is located on the inner circumferential side of the third welded portion, the second welded portion is located on the outer circumferential side of the third welded portion, the first welded portion, the second welded portion, and the third welded portion do not overlap in a thickness direction of the end cap, The current collecting component is a body portion for abutting and welding to the tab to form the first weld and the second weld; a protrusion protruding from an outer surface of the body portion along a direction facing the end cap and adapted to abut against and weld to the end cap to form the third weld; a recess is formed at a position of the current collecting part corresponding to the protrusion, the recess being recessed along a direction from an inner surface of the main body part toward the end cap, the protrusion has a first abutment surface for abutting against an end cap, the protrusion has a third connection portion located between the first abutment surface and a bottom surface of the recess, the third connection portion being used for welding to the end cap to form the third welded portion; The recess is an annular groove.

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