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

Abstract

The embodiments of the present application provide a battery cell, a battery, an electrical device, and a manufacturing method and equipment for a battery cell, which belong to the field of battery technology. Among them, the battery cell includes a shell, an electrode assembly, a current collecting component, and a pressure relief mechanism. The electrode assembly is used to be accommodated in the shell. The end cover is used to cover the opening of the shell. The current collecting component is used to connect the electrode assembly and the end cover. The pressure relief mechanism is arranged on the end cover. A recess is provided on the side of the end cover away from the electrode assembly, and the recess is used to accommodate at least a part of the pressure relief mechanism. The end cover forms a connecting portion in the area where the recess is provided, and the connecting portion is used to be welded with the current collecting component and form a first welding portion. The pressure relief mechanism covers the first welding portion along the thickness direction of the end cover. The size of the pressure relief mechanism in the direction perpendicular to the thickness of the end cover will not be limited by the first welding portion. The size of the recess and the pressure relief mechanism can be enlarged as needed, which is beneficial to improving the pressure relief capacity of the pressure relief mechanism and enhancing the safety of the battery cell.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery cell, a battery, an electrical device, and a method and equipment for manufacturing the battery cell. Background Art

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

[0003] In battery technology, both battery performance and safety need to be considered. Therefore, how to improve battery safety is an urgent problem to be solved in battery technology. Summary of the Invention

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

[0005] In a first aspect, an embodiment of the present application provides a battery cell, comprising: a shell having an opening; an electrode assembly for being accommodated in the shell; an end cover for covering the opening; a current collecting member located on a side of the electrode assembly facing the end cover, the current collecting member being used to connect the electrode assembly and the end cover to achieve electrical connection between the electrode assembly and the end cover; a pressure relief mechanism provided on the end cover, the pressure relief mechanism being used to actuate when the pressure or temperature inside the battery cell reaches a threshold value to relieve the pressure inside the battery cell; wherein a recess is provided on a side of the end cover facing away from the electrode assembly, the recess being used to accommodate at least a portion of the pressure relief mechanism, the end cover forming a connecting portion in the area where the recess is provided, the connecting portion being used to be welded to the current collecting member and forming a first welding portion, the pressure relief mechanism covering the first welding portion along the thickness direction of the end cover.

[0006] In the above technical solution, at least a portion of the pressure relief mechanism is housed within the recess of the end cap, reducing the space the pressure relief mechanism occupies outside the battery cell and making the battery cell smaller overall. Because the end cap forms a connection portion in the area where the recess is provided, the connection portion is welded to the current collecting member to form a first weld. The pressure relief mechanism covers the first weld along the thickness of the end cap, allowing the pressure relief mechanism and the first weld to be distributed throughout the thickness of the end cap. The size of the pressure relief mechanism in a direction perpendicular to the thickness of the end cap is not limited by the first weld. The size of the recess and the pressure relief mechanism can be increased as needed, which helps improve the pressure relief capacity of the pressure relief mechanism and enhances the safety of the battery cell.

[0007] In some embodiments, the pressure relief mechanism is welded to the end cover to form a second welding portion, and along the thickness direction, a projection of the second welding portion does not overlap with a projection of the first welding portion.

[0008] In the above technical solution, the pressure relief mechanism is welded to the end cap to form a second weld. This second weld serves to connect the pressure relief mechanism and the end cap, enhancing the securement of the pressure relief mechanism after it is mounted on the end cap. Because the projection of the second weld along the thickness of the end cap does not overlap with the projection of the first weld along the thickness of the end cap, the second weld is not formed in the location of the first weld during the welding process between the pressure relief mechanism and the end cap. This prevents damage to the first weld due to secondary welding and ensures the securement of the connection portion after welding to the current collecting component.

[0009] In some embodiments, both the first welding portion and the second welding portion extend along the circumference of the end cover, and the second welding portion is located on an outer circumferential side of the first welding portion.

[0010] In the above technical solution, the second welding portion is located on the outer peripheral side of the first welding portion, so that the projection of the second welding portion along the thickness direction of the end cover does not overlap with the projection of the first welding portion along the thickness direction of the end cover, and the circumferential dimension of the second welding portion in the end cover is larger, thereby improving the firmness of the pressure relief mechanism and the end cover after welding.

[0011] In some embodiments, along the circumference of the end cover, the second welding portions and the first welding portions are arranged alternately.

[0012] In the above technical solution, the second welding parts and the first welding parts are alternately arranged along the circumference of the end cover, so that the projection of the second welding parts along the thickness direction of the end cover does not overlap with the projection of the first welding parts along the thickness direction of the end cover.

[0013] In some embodiments, a side of the pressure relief mechanism facing the connecting portion is provided with an avoidance groove, and the avoidance groove is used to avoid the first welding portion.

[0014] In the above technical solution, an avoidance groove is provided on the pressure relief mechanism, which serves to avoid the first welding part, which is conducive to making the pressure relief mechanism rest against the connecting part, making the pressure relief mechanism more stable during the welding process with the end cover, and improving the welding quality of the pressure relief mechanism and the end cover.

[0015] In some embodiments, the pressure relief mechanism includes: a base, used to be welded with the end cover to form a second welding portion; a pressure relief portion, used to actuate when the pressure or temperature inside the battery cell reaches a threshold value to release the pressure inside the battery cell, the pressure relief portion is connected to the inner circumferential surface of the base, the pressure relief portion covers the first welding portion along the thickness direction, and the pressure relief portion and the base jointly define the avoidance groove.

[0016] In the above technical solution, the pressure relief part of the pressure relief mechanism is used to release the pressure inside the battery cell, and the base of the pressure relief mechanism is used to be welded and fixed to the end cover. The pressure relief part and the base together define a avoidance groove for avoiding the first welding part, so that the area where the avoidance groove is set in the pressure relief mechanism corresponds to the pressure relief part for pressure relief, and the structure is simple.

[0017] In some embodiments, the thickness of the pressure relief portion is smaller than the thickness of the base portion.

[0018] In the above technical solution, the thickness of the pressure relief portion is smaller than that of the base portion, so that the pressure relief mechanism is weaker in the area of ​​the pressure relief portion, which facilitates the release of pressure inside the battery cell.

[0019] In some embodiments, the base and the connecting portion are welded to form the second welding portion; or, the outer circumference of the base and the inner circumference of the recess are welded to form the second welding portion.

[0020] In the above technical solution, the base and the connecting part are welded to form a second welding part. The base and the connecting part can be welded together by penetration welding. The second welding part passes through the base and is combined with the connecting part, so that the pressure relief mechanism has good firmness after being welded to the end cover.

[0021] The outer circumference of the base and the inner circumference of the recess are welded to form a second welded portion, allowing the pressure relief mechanism to be welded to the end cap by seam welding. This method is simple and efficient. In addition, the second welded portion formed by welding the outer circumference of the base and the inner circumference of the recess is located away from the pressure relief portion, reducing the risk of damage to the pressure relief portion during welding.

[0022] In some embodiments, the end cover includes: a cover body for connecting to the shell, the cover body having an outer surface and an inner surface arranged opposite to each other along the thickness direction, the inner surface facing the current collecting component, and the recessed portion is recessed from the outer surface along the direction facing the current collecting component; a protruding portion protruding from the inner surface and located at a position of the cover body corresponding to the recessed portion, the protruding portion having abutting surface for abutting against the current collecting component, and the portion of the end cover located between the abutting surface and the bottom surface of the recessed portion is the connecting portion.

[0023] In the above technical solution, the protrusion is located at a position on the cover body corresponding to the recess and is provided protruding from the inner surface of the cover body. The protrusion reinforces the location of the recess on the cover body and allows the recess to be recessed as deeply as possible in the direction facing the current collecting member, thereby increasing the depth of the recess. Furthermore, the protrusion's protrusion from the inner surface of the cover body makes it easier to ensure the flatness of the abutment surface of the protrusion, allowing the protrusion to maintain good contact with the current collecting member, thereby ensuring the flow area between the current collecting member and the end cover.

[0024] In some embodiments, along the thickness direction, the bottom surface is closer to the current collecting member than the inner surface; or, the bottom surface is flush with the inner surface.

[0025] In the above technical solution, the bottom surface of the recess is closer to the current collecting component than the inner surface of the cover body along the thickness direction of the end cover, or the bottom surface of the recess is flush with the inner surface of the cover body. On the one hand, the depth of the recess is increased, thereby increasing the space of the recess for accommodating the pressure relief mechanism; on the other hand, the distance between the abutting surface of the protrusion and the bottom surface of the recess is relatively small, so that the thickness of the connecting part is relatively small, which facilitates welding the connecting part and the current collecting component from the outside of the end cover, thereby improving the firmness of the connecting part and the current collecting component after welding.

[0026] In some embodiments, the pressure relief mechanism is entirely housed within the recess.

[0027] In the above technical solution, the pressure relief mechanism is entirely accommodated in the recess, and the pressure relief mechanism does not occupy the space outside the recess, thereby further reducing the overall volume of the battery cell.

[0028] In some embodiments, a hole is provided on the connecting portion, the hole passes through two surfaces of the connecting portion that are opposite to each other along the thickness direction, and the pressure relief mechanism covers the hole along the thickness direction.

[0029] In the above technical solution, a hole is provided through the connecting portion, which can relieve stress generated during welding between the connecting portion and the current collecting member. The pressure relief mechanism covers the hole along the thickness of the end cap, and when the pressure relief mechanism is activated, it can release pressure within the battery cell through the hole.

[0030] In some embodiments, the first welding portion extends along the circumference of the hole, the hole is located on the inner circumference of the welding portion, and the hole is used to inject electrolyte into the interior of the battery cell.

[0031] In the above technical solution, the hole on the connecting portion is an electrolyte injection hole, and the electrolyte can be injected into the battery cell through the hole.

[0032] In some embodiments, the current collecting component is provided with a first central hole and a guide channel for the electrolyte to enter the battery cell. The guide channel is arranged around the first central hole. Along the thickness direction, the first central hole and the channel are arranged opposite to each other.

[0033] In the above technical solution, the first center hole and the channel are arranged opposite to each other along the thickness direction of the end cover, and the guide channel is arranged around the first center hole. In the process of injecting electrolyte into the battery cell through the channel, the electrolyte can not only flow into the battery cell along the first center hole, but also flow into the battery cell along the guide channel, thereby improving the injection efficiency and allowing the electrolyte to better infiltrate the electrode assembly.

[0034] In some embodiments, the flow guide channel includes a flow guide hole, which passes through two surfaces of the collecting component arranged opposite to each other along the thickness direction; and / or, the flow guide channel includes a flow guide groove, which is arranged on at least one surface of the collecting component in the thickness direction.

[0035] In the above technical solution, the flow-guiding channel can be a flow-guiding hole extending through both surfaces of the current collecting member along the thickness direction. The electrolyte entering through the hole can quickly flow through the flow-guiding hole from the side of the current collecting member facing the end cap to the side facing away from the end cap. The flow-guiding channel can also be a flow-guiding groove provided on the surface of the current collecting member. The electrolyte entering through the hole can flow laterally along the flow-guiding groove, facilitating the electrolyte entering the electrode assembly to wet the electrode sheets.

[0036] In a second aspect, an embodiment of the present application provides a battery, comprising: a battery cell provided in any one embodiment of the first aspect above; and a box for accommodating the battery cell.

[0037] In a third aspect, an embodiment of the present application provides an electrical device, comprising a battery provided by any one of the embodiments of the second aspect above.

[0038] In a fourth aspect, an embodiment of the present application provides a method for manufacturing a battery cell, the manufacturing method comprising: providing a shell having an opening; providing an electrode assembly; providing an end cover, the end cover being provided with a recess, the end cover forming a connection portion in the area where the recess is provided to provide a current collecting member; providing a pressure relief mechanism, the pressure relief mechanism being used to actuate when the pressure or temperature inside the battery cell reaches a threshold value to relieve the pressure inside the battery cell; accommodating the electrode assembly in the shell; connecting the current collecting member to the electrode assembly; covering the end cover with the opening so that the recess is located on the side of the end cover away from the electrode assembly; welding the connection portion to the current collecting member to form a first welding portion; installing the pressure relief mechanism in the end cover so that at least a portion of the pressure relief mechanism is accommodated in the recess, so that the pressure relief mechanism covers the first welding portion along the thickness direction of the end cover.

[0039] In a fifth aspect, an embodiment of the present application further provides a manufacturing device for a battery cell, the manufacturing device comprising: a first providing device for providing a shell having an opening; a second providing device for providing an electrode assembly; a third providing device for providing an end cover, the end cover being provided with a recess, the end cover forming a connection portion in the area where the recess is provided; a fourth providing device for providing a current collecting component; a fifth providing device for providing a pressure relief mechanism, the pressure relief mechanism being activated when the pressure or temperature inside the battery cell reaches a threshold value to relieve the pressure inside the battery cell; an assembling device for: accommodating the electrode assembly in the shell; connecting the current collecting component to the electrode assembly; covering the end cover on the opening so that the recess is located on the side of the end cover away from the electrode assembly; welding the connection portion to the current collecting component to form a first welding portion; installing the pressure relief mechanism in the end cover so that at least a portion of the pressure relief mechanism is accommodated in the recess, so that the pressure relief mechanism covers the first welding portion along the thickness direction of the end cover. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0041] Figure 1 A schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0042] Figure 2 A schematic diagram of the structure of a battery provided in some embodiments of the present application;

[0043] Figure 3 An exploded view of a battery cell provided in some embodiments of the present application;

[0044] Figure 4 for Figure 3 A cross-sectional view of a battery cell is shown;

[0045] Figure 5 Bottom views of battery cells provided in some other embodiments of the present application;

[0046] Figure 6 for Figure 4 A partial view of a battery cell is shown;

[0047] Figure 7 for Figure 6 Schematic diagram of the connection between the pressure relief mechanism and the end cover shown;

[0048] Figure 8 A schematic diagram of the connection between the pressure relief mechanism and the end cover provided in other embodiments of the present application;

[0049] Figure 9 for Figure 6 The structural schematic diagram of the current collecting component shown;

[0050] Figure 10 A flowchart of a method for manufacturing a battery cell provided in some embodiments of the present application;

[0051] Figure 11 A schematic block diagram of a battery cell manufacturing device provided in some embodiments of the present application.

[0052] Icons: 10-case; 11-first part; 12-second part; 20-battery cell; 21-housing; 22-electrode assembly; 221-positive electrode tab; 222-negative electrode tab; 223-second center hole; 23-end cover; 231-recess; 2311-bottom surface; 232-connecting portion; 2321-channel; 233-cover; 2331-outer surface; 2332-inner surface; 234-protrusion; 2341-rest surface; 24-current collecting member; 241-first center hole; 242-flow guide channel; 2 5-pressure relief mechanism; 251-avoidance groove; 252-base; 253-pressure relief part; 2531-notched groove; 26-electrode terminal; 27-first welding part; 28-second welding part; 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-fifth providing device; 2600-assembly device; Z-thickness direction. DETAILED DESCRIPTION

[0053] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0054] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first" and "second" in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.

[0055] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments.

[0056] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0057] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0058] In the embodiments of this application, the same reference numerals represent 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 thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.

[0059] The term "plurality" used in this application refers to two or more (including two).

[0060] In this application, battery cells may include lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, etc., and the embodiments of this application do not limit this. Battery cells may be cylindrical, flat, rectangular, or other shapes, etc., and the embodiments of this application do not limit this. Battery cells are generally divided into three types based on the packaging method: cylindrical battery cells, prismatic battery cells, and soft-pack battery cells, and the embodiments of this application do not limit this.

[0061] The battery referred to in the embodiments of this 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 this application may include a battery module or a battery pack. A battery generally includes a casing that encloses one or more battery cells. The casing prevents liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0062] A battery cell includes an electrode assembly and an electrolyte. The electrode assembly consists of a positive electrode sheet, a negative electrode sheet, and a separator. A battery cell primarily operates by the movement of metal ions between the positive and negative electrode sheets. The positive electrode sheet includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive electrode collector. The uncoated positive electrode collector protrudes from the coated positive electrode collector, and the uncoated positive electrode collector serves as the positive electrode tab. For lithium-ion batteries, for example, the positive electrode current collector can be made of aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The negative electrode sheet includes a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative electrode collector. The uncoated negative electrode collector protrudes from the coated negative electrode collector, and the uncoated negative electrode collector serves as the negative electrode tab. The negative electrode current collector can be made of copper, and the negative electrode active material can be carbon or silicon, among others. To ensure that high currents can pass without fusing, multiple positive electrode tabs are stacked together, and multiple negative electrode tabs are stacked together. The separator can be made of materials such as PP (polypropylene) or PE (polyethylene). Furthermore, the electrode assembly can be a wound or laminated structure, but the embodiments of the present application are not limited thereto.

[0063] The development of battery technology must take into account multiple design factors at the same time, such as energy density, cycle life, discharge capacity, charge and discharge rate and other performance parameters. In addition, battery safety must also be considered.

[0064] For battery cells, the main safety hazards come from the charging and discharging process, as well as the appropriate ambient temperature design. In order to effectively avoid unnecessary losses, there are generally at least three protection measures for battery cells. Specifically, the protection measures include at least switching elements, selection of appropriate isolation membrane materials, and pressure relief mechanisms. The switching element refers to an element that can stop the battery from charging or discharging when the temperature or resistance inside the battery cell reaches a certain threshold. The isolation membrane is used to isolate the positive and negative pole pieces. When the temperature rises to a certain value, it can automatically dissolve the micron-level (or even nano-level) micropores attached to it, so that metal ions cannot pass through the isolation membrane, terminating the internal reaction of the battery cell.

[0065] A pressure relief mechanism is a component that activates to release pressure or temperature inside a battery cell when the pressure or temperature reaches a predetermined threshold. This threshold varies depending on the design requirements. It may be determined by one or more of the materials in the battery cell: the positive electrode sheet, the negative electrode sheet, the electrolyte, and the separator.

[0066] The "activation" mentioned in this application refers to the action of the pressure relief mechanism or its activation to a certain state, thereby allowing the pressure and temperature inside the battery cell to be released. The action produced by the pressure relief mechanism may include, but is not limited to: at least a portion of the pressure relief mechanism is ruptured, broken, torn or opened, etc. When the pressure relief mechanism is actuated, the high-temperature and high-pressure substances inside the battery cell will be discharged outward from the actuated part as emissions. In this way, the pressure and temperature of the battery cell can be relieved under controllable pressure or temperature, thereby avoiding potential more serious accidents.

[0067] For typical battery cells, the end caps need to be electrically connected to the electrode assembly, allowing the end caps to function as an output terminal for the battery cell to output electrical energy. To better achieve this electrical connection between the end caps and the tabs, a current collecting member is typically positioned between the electrode assembly and the end caps. This current collecting member connects the end caps and electrode assembly to achieve electrical connection between the end caps and the electrode assembly.

[0068] The inventors noted that to ensure the stability of the flow between the end cap and the current collecting member, the end cap and current collecting member are generally welded together. A welding groove is provided on the outside of the end cap, and the end cap is welded to the current collecting member in the area where the welding groove is provided to form a welded portion. At the same time, to ensure the safety of the battery cell, a pressure relief mechanism is generally provided on the end cap. In the direction perpendicular to the thickness of the end cap, the welding groove is located on the outside of the pressure relief mechanism, and the welded portion is also located on the outside of the pressure relief mechanism. The pressure relief mechanism is limited by the welding groove and the welded portion and cannot be increased in size, resulting in insufficient pressure relief capacity of the pressure relief mechanism. The pressure relief capacity of the pressure relief mechanism is poor, and the internal emissions of the battery cell cannot be discharged in time when thermal runaway occurs, which makes it easy for the battery cell to explode or catch fire, resulting in poor safety of the battery cell.

[0069] Based on the above considerations, in order to solve the problem of poor safety of battery cells, the inventors have designed a battery cell after in-depth research. A recess is provided on the side of the end cover facing away from the electrode assembly, and the recess is used to accommodate at least a part of the pressure relief mechanism. The end cover forms a connecting portion in the area where the recess is provided, and the connecting portion is used to be welded to the current collecting component and form a first welding portion. The pressure relief mechanism covers the first welding portion along the thickness direction of the end cover.

[0070] In such a battery cell, since the end cover forms a connecting portion in the area where the recess is provided, the connecting portion is welded to the current collecting member to form a first welding portion, and the pressure relief mechanism covers the first welding portion along the thickness direction of the end cover, so that the pressure relief mechanism and the first welding portion are distributed in the thickness direction of the end cover. The size of the pressure relief mechanism in the direction perpendicular to the thickness of the end cover will not be restricted by the first welding portion. The size of the recess and the pressure relief mechanism can be enlarged as needed, which is beneficial to improving the pressure relief capacity of the pressure relief mechanism and enhancing the safety of the battery cell.

[0071] The technical solutions described in the embodiments of the present application are applicable to batteries and electrical devices using batteries.

[0072] Electrical equipment can be vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and electric tools, etc. Vehicles can be fuel vehicles, gas vehicles, or new energy vehicles. New energy vehicles can be pure electric vehicles, hybrid vehicles, or extended-range vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical equipment.

[0073] For the convenience of description, the following embodiments are described by taking the electric device as a vehicle as an example.

[0074] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of the present application. A battery 100 is disposed inside the vehicle 1000. The battery 100 can be disposed at the bottom, head, or tail of the vehicle 1000. The battery 100 can be used to power the vehicle 1000. For example, the battery 100 can serve as an operating power source for the vehicle 1000.

[0075] 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, to meet the power requirements of the vehicle 1000 during startup, navigation, and driving.

[0076] 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 serve 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.

[0077] Please refer to Figure 2 , Figure 2 This is a structural diagram of a battery 100 provided in some embodiments of the present application. The battery 100 includes a box body 10 and a battery cell 20 . The box body 10 is used to accommodate the battery cell 20 .

[0078] The housing 10 is a component that houses the battery cells 20, providing a storage space for the battery cells 20. The housing 10 can have various structures. In some embodiments, the housing 10 can include a first portion 11 and a second portion 12, which overlap to define a storage space for the battery cells 20. The first portion 11 and the second portion 12 can have various shapes, such as a rectangular parallelepiped or a cylinder. The first portion 11 can be a hollow structure with one side open, and the second portion 12 can also be a hollow structure with one side open. The open side of the second portion 12 overlaps the open side of the first portion 11, forming the housing 10 with a storage space. Alternatively, the first portion 11 can be a hollow structure with one side open, and the second portion 12 can be a plate-like structure. The second portion 12 overlaps the open side of the first portion 11, forming the housing 10 with a storage space. The first portion 11 and the second portion 12 can be sealed by a sealing element, such as a sealing ring, sealant, etc.

[0079] In the battery 100, there can be one or more battery cells 20. If there are multiple battery cells 20, the multiple battery cells 20 can be connected in series, parallel, or in a hybrid connection. A hybrid connection refers to a combination of series and parallel connections among the multiple battery cells 20. Multiple battery cells 20 can be connected in series, parallel, or in a hybrid connection to form a battery module, which is then connected in series, parallel, or in a hybrid connection to form a whole and housed within the housing 10. Alternatively, all battery cells 20 can be directly connected in series, parallel, or in a hybrid connection, and then the whole battery module can be housed within the housing 10.

[0080] In some embodiments, the battery 100 may further include a busbar component, through which the multiple battery cells 20 can be electrically connected to each other, thereby enabling series connection, parallel connection, or hybrid connection of the multiple battery cells 20. The busbar component may be a metal conductor, such as copper, iron, aluminum, stainless steel, or aluminum alloy.

[0081] Please refer to Figure 3 , Figure 3 This is an exploded view of a battery cell 20 provided in some embodiments of the present application. The battery cell 20 includes a housing 21 , an electrode assembly 22 , an end cover 23 , a current collecting member 24 and a pressure relief mechanism 25 .

[0082] The housing 21 is a component for accommodating the electrode assembly 22. The housing 21 may be a hollow structure with an opening at one end and a cavity therein for accommodating the electrode assembly 22. Alternatively, the housing 21 may be a hollow structure with openings at opposite ends and a cavity therein for accommodating the electrode assembly 22. The housing 21 may have various shapes, such as a cylinder or a rectangular parallelepiped. The housing 21 may be made of various materials, such as copper, iron, aluminum, steel, and aluminum alloys.

[0083] The electrode assembly 22 is the component where the electrochemical reaction occurs in the battery cell 20. The electrode assembly 22 may include a positive electrode sheet, a negative electrode sheet, and a separator. The electrode assembly 22 may be a wound structure formed by winding the positive electrode sheet, the separator, and the negative electrode sheet, or a laminated structure formed by stacking the positive electrode sheet, the separator, and the negative electrode sheet. The electrode assembly 22 has a positive electrode tab 221 and a negative electrode tab 222 ( Figure 3 The positive electrode tab 221 may be a portion of the positive electrode sheet that is not coated with the positive electrode active material layer, and the negative electrode tab 222 may be a portion of the negative electrode sheet that is not coated with the negative electrode active material layer.

[0084] The end cap 23 covers the opening of the housing 21 to isolate the internal environment of the battery cell 20 from the external environment. The shape of the end cap 23 can be compatible with the shape of the housing 21. For example, if the housing 21 is a rectangular parallelepiped structure, the end cap 23 can be a rectangular plate-shaped structure that matches the housing 21. For another example, if the housing 21 is a cylindrical structure, the end cap 23 can be a circular plate-shaped structure that matches the housing 21. The end cap 23 can also be made of a variety of materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. The material of the end cap 23 can be the same as or different from the material of the housing 21.

[0085] In the battery cell 20, there can be one or two end caps 23, and the number of end caps 23 can be determined based on the specific structure of the housing 21. For example, if the housing 21 is a hollow structure with an opening at one end, one end cap 23 can be provided. For another example, if the housing 21 is a hollow structure with openings at two opposite ends, two end caps 23 can be provided, with the two end caps 23 covering the two openings of the end cap 23 respectively.

[0086] The current collecting component 24 is a conductor, and the current collecting component 24 can be a metal conductor such as copper, iron, aluminum, steel, or aluminum alloy. In the battery cell 20, there can be one or two current collecting components 24. In the embodiment where there is one end cover 23 in the battery cell 20, one current collecting component 24 can be provided accordingly, and the electrode assembly 22 can be connected to the end cover 23 through the current collecting component 24. Exemplarily, the positive pole tab 221 of the electrode assembly 22 is connected to the end cover 23 through the current collecting component 24, and the negative pole tab 222 of the electrode assembly 22 is connected to the shell 21, so that the end cover 23 and the shell 21 serve as two output poles of opposite polarity of the battery cell 20 respectively. In the embodiment where there are two end covers 23 in the battery cell 20, two current collecting components 24 can be provided accordingly, and one current collecting component 24 is provided for each end cover 23. Exemplarily, as Figure 3 As shown, the positive electrode tab 221 of the electrode assembly 22 is connected to the electrode terminal 26 on one end cover 23 through a current collecting component 24, and the negative electrode tab 222 of the electrode assembly 22 is connected to the other end cover 23 through another current collecting component 24, so that the electrode terminal 26 of one end cover 23 and the other end cover 23 respectively serve as two output poles with opposite polarities of the battery cell 20.

[0087] The pressure relief mechanism 25 is a component that releases pressure within the battery cell 20. When the pressure or temperature within the battery cell 20 reaches a threshold, the pressure within the battery cell 20 is released through the pressure relief mechanism 25. The pressure relief mechanism 25 can take the form of, for example, an explosion-proof valve, an explosion-proof disk, an air valve, a pressure relief valve, or a safety valve, and can specifically employ a pressure-sensitive or temperature-sensitive element or structure. That is, when the pressure or temperature within the battery cell 20 reaches a predetermined threshold, the pressure relief mechanism 25 activates or a weak structure within the pressure relief mechanism 25 is destroyed, thereby forming an opening or channel for the pressure or temperature within the battery cell 20 to be released.

[0088] Please refer to Figure 4 , Figure 4 for Figure 3The cross-sectional view of the battery cell 20 shown in the figure, an embodiment of the present application provides a battery cell 20, including a shell 21, an electrode assembly 22, an end cover 23, a current collecting member 24 and a pressure relief mechanism 25. The shell 21 has an opening. The electrode assembly 22 is used to be accommodated in the shell 21. The end cover 23 is used to cover the opening. The current collecting member 24 is located on the side of the electrode assembly 22 facing the end cover 23, and the current collecting member 24 is used to connect the electrode assembly 22 and the end cover 23 to achieve electrical connection between the electrode assembly 22 and the end cover 23. The pressure relief mechanism 25 is provided on the end cover 23, and the pressure relief mechanism 25 is used to actuate when the pressure or temperature inside the battery cell 20 reaches a threshold value to relieve the pressure inside the battery cell 20.

[0089] Among them, a recess 231 is provided on the side of the end cover 23 facing away from the electrode assembly 22, and the recess 231 is used to accommodate at least a portion of the pressure relief mechanism 25. The end cover 23 forms a connecting portion 232 in the area where the recess 231 is set, and the connecting portion 232 is used to be welded with the current collecting component 24 and form a first welding portion 27. The pressure relief mechanism 25 covers the first welding portion 27 along the thickness direction Z of the end cover 23.

[0090] The pressure relief mechanism 25 is a component for releasing the pressure inside the battery cell 20. The pressure relief mechanism 25 and the end cap 23 can be connected in various ways, such as bonding, welding, interference fit connection, etc.

[0091] The current collecting member 24 is connected to both the end cap 23 and the electrode assembly 22 to achieve electrical connection between the electrode assembly 22 and the end cap 23. The current collecting member 24 can connect the end cap 23 to the positive electrode tab 221 of the electrode assembly 22, or it can connect the end cap 23 to the negative electrode tab 222 of the electrode assembly 22. The current collecting member 24 and the positive electrode tab 221 or the negative electrode tab 222 can be connected in a non-fixed manner, such as by abutting contact between the current collecting member 24 and the positive electrode tab 221 or the negative electrode tab 222; or the current collecting member 24 and the positive electrode tab 221 or the negative electrode tab 222 can be connected in a fixed manner, such as by welding the current collecting member 24 and the positive electrode tab 221 or the negative electrode tab 222.

[0092] The recess 231 is provided on the side of the end cover 23 facing away from the electrode assembly 22. It is understandable that the opening of the recess 231 faces away from the electrode assembly 22. The recess 231 is recessed from the surface of the end cover 23 facing away from the electrode assembly 22 in the direction facing the electrode assembly 22, and the opening of the recess 231 is formed on the surface. The recess 231 can be in a variety of shapes, such as circular, square, etc. The recess 231 provides space for the pressure relief mechanism 25. The pressure relief mechanism 25 can be fully accommodated in the recess 231, or partially accommodated in the recess 231. For example, in the thickness direction Z direction of the end cover 23, a portion of the pressure relief mechanism 25 is located in the recess 231, and a portion is located outside the recess 231.

[0093] The end cover 23 forms a connecting portion 232 in the area where the recess 231 is set. The connecting portion 232 is the portion of the end cover 23 located at the bottom of the recess 231. It can also be understood that the connecting portion 232 is the portion remaining in the recess direction of the recess 231 after the end cover 23 is set with the recess 231.

[0094] The first weld 27 is the portion where the connecting portion 232 and the current collecting member 24 are connected after being welded to each other. The area where the weld mark is formed between the connecting portion 232 and the current collecting member 24 forms the first weld 27. For example, if the connecting portion 232 and the current collecting member 24 are welded together using penetration welding, the first weld 27 may be the portion where the connecting portion 232 and the current collecting member 24 are welded together.

[0095] The pressure relief mechanism 25 covers the first welding portion 27 along the thickness direction Z of the end cover 23, that is, the pressure relief mechanism 25 completely covers the first welding portion 27 along the thickness direction Z of the end cover 23. It can also be understood that the first welding portion 27 is located in the area formed by the projection of the pressure relief mechanism 25 along the thickness direction Z of the end cover 23.

[0096] In the embodiment of the present application, at least a portion of the pressure relief mechanism 25 is housed within the recess 231 of the end cap 23, reducing the space occupied by the pressure relief mechanism 25 outside the battery cell 20 and making the battery cell 20 smaller overall. Because the end cap 23 forms a connecting portion 232 in the area where the recess 231 is located, the connecting portion 232 is welded to the current collecting member 24 to form a first weld 27. The pressure relief mechanism 25 covers the first weld 27 along the thickness direction Z of the end cap 23, so that the pressure relief mechanism 25 and the first weld 27 are distributed in the thickness direction Z of the end cap 23. The size of the pressure relief mechanism 25 perpendicular to the thickness direction Z of the end cap 23 is not limited by the first weld 27. The size of the recess 231 and the pressure relief mechanism 25 can be increased as needed, which helps improve the pressure relief capacity of the pressure relief mechanism 25 and enhances the safety of the battery cell 20.

[0097] In some embodiments, please refer to Figure 4 The pressure relief mechanism 25 is welded to the end cover 23 to form a second welding portion 28 . Along the thickness direction Z of the end cover 23 , the projection of the second welding portion 28 does not overlap with the projection of the first welding portion 27 .

[0098] The second weld 28 is the portion connecting the pressure relief mechanism 25 and the end cover 23 after welding. The area where the weld mark is formed between the pressure relief mechanism 25 and the end cover 23 forms the second weld 28. For example, if the pressure relief mechanism 25 and the end cover 23 are welded together using penetration welding, the second weld 28 may be the portion where the pressure relief mechanism 25 and the connection portion 232 of the end cover 23 are welded together. For example, if the pressure relief mechanism 25 and the end cover 23 are welded together using seam welding, the second weld 28 may be the solder connecting the outer circumferential surface of the pressure relief mechanism 25 and the inner circumferential surface of the recess 231.

[0099] In this embodiment, the pressure relief mechanism 25 is welded to the end cap 23 to form a second weld 28. The second weld 28 serves to connect the pressure relief mechanism 25 and the end cap 23, thereby enhancing the securement of the pressure relief mechanism 25 after being mounted on the end cap 23. Because the projection of the second weld 28 along the thickness direction Z of the end cap 23 does not overlap with the projection of the first weld 27 along the thickness direction Z of the end cap 23, during the process of welding the pressure relief mechanism 25 to the end cap 23 to form the second weld 28, the second weld 28 is not formed in the location of the first weld 27. This prevents damage to the first weld 27 caused by secondary welding and ensures the securement of the connection portion 232 after being welded to the current collecting member 24.

[0100] In some embodiments, please refer to Figure 4 The first welding portion 27 and the second welding portion 28 both extend along the circumferential direction of the end cover 23 , and the second welding portion 28 is located on the outer peripheral side of the first welding portion 27 .

[0101] The first weld portion 27 may be a closed structure extending along the circumference of the end cap 23, for example, the first weld portion 27 may be an annular structure. The first weld portion 27 may also be a non-closed structure extending along the circumference of the end cap 23, for example, the first weld portion 27 may be divided into multiple sections, and the multiple sections may be arranged at intervals along the circumference of the end cap 23. The second weld portion 28 may be a closed structure extending along the circumference of the end cap 23, for example, the second weld portion 28 may be an annular structure. The second weld portion 28 may also be a non-closed structure extending along the circumference of the end cap 23, for example, the second weld portion 28 may be divided into multiple sections, and the multiple sections may be arranged at intervals along the circumference of the end cap 23.

[0102] The second welding portion 28 is located on the outer peripheral side of the first welding portion 27, so that the second welding portion 28 and the first welding portion 27 are staggered in the radial direction of the end cover 23. Figure 4 As shown, taking the first welding portion 27 and the second welding portion 28 as an example, both of which are annular structures, the second welding portion 28 is located on the outer peripheral side of the first welding portion 27, so that the first welding portion 27 is an inner ring and the second welding portion 28 is an outer ring.

[0103] In this embodiment, the second welding portion 28 is located on the outer peripheral side of the first welding portion 27, so that the projection of the second welding portion 28 along the thickness direction Z of the end cover 23 does not overlap with the projection of the first welding portion 27 along the thickness direction Z of the end cover 23, and the circumferential dimension of the second welding portion 28 on the end cover 23 is larger, thereby improving the firmness of the pressure relief mechanism 25 and the end cover 23 after welding.

[0104] In other embodiments, please refer to Figure 5 , Figure 5 In a bottom view of a battery cell 20 provided in some other embodiments of the present application, the second welds 28 and the first welds 27 are arranged alternately along the circumference of the end cap 23. This arrangement simplifies the arrangement by ensuring that the projections of the second welds 28 along the thickness direction Z of the end cap 23 do not overlap with the projections of the first welds 27 along the thickness direction Z of the end cap 23.

[0105] The second welding portion 28 and the first welding portion 27 are arranged alternately, so that the first welding portion 27 and the second welding portion 28 are staggered in the circumferential direction of the end cover 23. The first welding portion 27 and the second welding portion 28 can be one or more. Figure 5 In the embodiment, there are two first welding portions 27 and two second welding portions 28.

[0106] Exemplarily, the first welding portion 27 and the second welding portion 28 are both V-shaped.

[0107] In some embodiments, please refer to Figure 6 , Figure 6 for Figure 4 In the partial view of the battery cell 20 shown, a relief groove 251 is provided on the side of the pressure relief mechanism 25 facing the connecting portion 232 , and the relief groove 251 is used to avoid the first welding portion 27 .

[0108] The escape groove 251 is a space on the pressure relief mechanism 25 that allows the first weld portion 27 to escape. The escape groove 251 can accommodate the portion of the first weld portion 27 that protrudes from the connecting portion 232. The escape groove 251 can be circular, square, or other shapes. For example, if the first weld portion 27 is annular, the escape groove 251 is a circular structure coaxially arranged with the first weld portion 27.

[0109] It should be noted that, no matter the first welding portion 27 and the second welding portion 28 are staggered in the radial direction of the end cover 23 or in the circumferential direction of the end cover 23, an avoidance groove 251 for avoiding the first welding portion 27 can be provided on the side of the pressure relief mechanism 25 facing the connecting portion 232.

[0110] In this embodiment, the avoidance groove 251 serves to avoid the first welding portion 27, which is conducive to the pressure relief mechanism 25 being against the connecting portion 232, making the pressure relief mechanism 25 more stable during the welding process with the end cover 23, thereby improving the welding quality of the pressure relief mechanism 25 and the end cover 23.

[0111] In some embodiments, please refer to Figure 7 , Figure 7 for Figure 6 The diagram shows the connection between the pressure relief mechanism 25 and the end cap 23. The pressure relief mechanism 25 includes a base 252 and a pressure relief portion 253. The base 252 is welded to the end cap 23 to form a second weld 28. The pressure relief portion 253 is activated when the pressure or temperature inside the battery cell 20 reaches a threshold value to release the pressure inside the battery cell 20. The pressure relief portion 253 is connected to the inner circumference of the base 252. The pressure relief portion 253 covers the first weld 27 along the thickness direction Z of the end cap 23. The pressure relief portion 253 and the base 252 together define an escape groove 251.

[0112] The base 252 is the portion where the pressure relief mechanism 25 is welded to the end cap 23, and the pressure relief portion 253 is the portion where the pressure relief mechanism 25 releases the pressure inside the battery cell 20. The base 252 and the pressure relief portion 253 may be integrally formed.

[0113] Exemplarily, the pressure relief mechanism 25 is a circular explosion-proof disk, the base 252 is annular in structure, the pressure relief portion 253 is circular in structure, and the outer circumference of the pressure relief portion 253 is connected to the inner circumference of the base 252. The inner circumference of the base 252 refers to the surface located inside the base 252 and extending along the thickness direction Z of the end cap 23. Taking the annular base 252 as an example, the inner circumference of the base 252 is the surface of the circular inner side of the base 252.

[0114] The avoidance groove 251 is defined by the pressure relief portion 253 and the base 252 . The side surface of the avoidance groove 251 is the inner circumferential surface of the base 252 . The bottom surface 2311 of the avoidance groove 251 is the surface of the pressure relief portion 253 facing the connecting portion 232 .

[0115] When the pressure or temperature inside the battery cell 20 reaches a threshold, the pressure relief portion 253 is actuated so that the pressure relief portion 253 is broken, shattered, torn or opened. Figure 7 In the embodiment, the pressure relief portion 253 is provided with a notch 2531 . When the internal pressure or temperature of the battery cell 20 reaches a threshold, the pressure relief portion 253 ruptures at the position of the notch 2531 to form an opening for releasing the pressure or temperature inside the battery cell 20 .

[0116] In this embodiment, the pressure relief portion 253 and the base 252 jointly define an avoidance groove 251 for avoiding the first welding portion 27, so that the area where the pressure relief mechanism 25 is provided with the avoidance groove 251 corresponds to the formation of the pressure relief portion 253 for pressure relief. The structure is simple, which is conducive to the pressure relief mechanism 25 to release the pressure inside the battery cell 20.

[0117] In some embodiments, please refer to Figure 7 , the thickness of the pressure relief portion 253 is smaller than the thickness of the base 252 .

[0118] The thickness of the pressure relief portion 253 is the dimension of the pressure relief portion 253 in the thickness direction Z of the end cover 23 , and the thickness of the base portion 252 is the dimension of the pressure relief portion 253 in the thickness direction Z of the end cover 23 .

[0119] Illustratively, along the thickness direction Z of the end cover 23 , a surface of the pressure relief portion 253 facing away from the connecting portion 232 is coplanar with a surface of the base portion 252 facing away from the connecting portion 232 .

[0120] The thickness of the pressure relief portion 253 is smaller than that of the base portion 252, making the pressure relief mechanism 25 weaker in the region of the pressure relief portion 253, thereby facilitating the release of pressure within the battery cell 20. If the pressure relief portion 253 is provided with a notched groove 2531, the notched groove 2531 does not need to be too deep to allow the pressure relief portion 253 to be actuated to release pressure within the battery cell 20.

[0121] In some embodiments, please refer to Figure 7 The outer peripheral surface of the base portion 252 is welded to the inner peripheral surface of the recessed portion 231 to form a second welding portion 28 .

[0122] The outer circumferential surface of the base 252 refers to the surface located outside the base 252 and extending along the thickness direction Z of the end cap 23. Taking the ring-shaped base 252 as an example, the outer circumferential surface of the base 252 is the circular surface outside the base 252. The inner circumferential surface of the recessed portion 231 is the surface of the recessed portion 231 extending along the thickness direction Z of the end cap 23.

[0123] The second welding portion 28 is located in the gap formed between the outer circumference of the base 252 and the inner circumference of the recess 231, so that the second welding portion 28 is away from the pressure relief portion 253, thereby reducing the risk of damage to the pressure relief portion 253 during welding of the pressure relief mechanism 25. The pressure relief mechanism 25 can be welded to the end cover 23 by seam welding, which is simple and efficient.

[0124] In other embodiments, please refer to Figure 8 , Figure 8 This is a schematic diagram of the connection between the pressure relief mechanism 25 and the end cover 23 provided in some other embodiments of the present application, where the base 252 and the connecting portion 232 are welded to form a second welding portion 28 .

[0125] The base 252 and the connecting portion 232 can be welded together by penetration welding. The second welding portion 28 passes through the base 252 and is combined with the connecting portion 232, so that the pressure relief mechanism 25 has good firmness after being welded to the end cover 23.

[0126] In some embodiments, please refer to Figure 6-Figure 8 The end cap 23 includes a cover body 233 and a protrusion 234. The cover body 233 is used to connect to the housing 21. The cover body 233 has an outer surface 2331 and an inner surface 2332 arranged opposite each other along the thickness direction Z of the end cap 23. The inner surface 2332 faces the current collecting member 24, and the recess 231 is recessed from the outer surface 2331 in a direction facing the current collecting member 24. The protrusion 234 is provided protruding from the inner surface 2332 and is located at a position on the cover body 233 corresponding to the recess 231. The protrusion 234 has an abutment surface 2341 for abutting against the current collecting member 24. The portion of the end cap 233 located between the abutment surface 2341 and the bottom surface 2311 of the recess 231 constitutes the connecting portion 232.

[0127] The cover 233 is the main portion connecting the end cap 23 to the housing 21, and the protrusion 234 is the portion of the end cap 23 that protrudes from the cover 233. The cover 233 can have a plate-like structure, and the protrusion 234 can be a boss provided on the inner surface 2332 of the cover 233. The inner surface 2332 of the cover 233 is the surface of the cover 233 facing the current collecting member 24 along the thickness direction Z of the end cap 23. The outer surface 2331 of the cover 233 is the surface of the cover 233 facing away from the current collecting member 24 along the thickness direction Z of the end cap 23. The abutment surface 2341 of the protrusion 234 is the end surface of the protrusion 234 facing away from the cover 233 along the thickness direction Z of the end cap 23. The bottom surface 2311 of the recess 231 is the surface of the recess 231 closest to the current collecting member 24 along the thickness direction Z of the end cover 23. Along the thickness direction Z of the end cover 23, the bottom surface 2311 of the recess 231 and the abutting surface 2341 of the protrusion 234 are respectively two surfaces of the connecting portion 232.

[0128] In this embodiment, the protrusion 234 is located at a position on the cover 233 corresponding to the recess 231 and is protruded from the inner surface 2332 of the cover 233. The protrusion 234 reinforces the position of the recess 231 on the cover 233 and allows the recess 231 to be recessed as deeply as possible in the direction facing the current collecting member 24, thereby increasing the depth of the recess 231. Furthermore, the protrusion 234 protruding from the inner surface 2332 of the cover 233 makes it easier to ensure the flatness of the abutment surface 2341, allowing the protrusion 234 to maintain good contact with the current collecting member 24, thereby ensuring the flow area between the current collecting member 24 and the end cap 23.

[0129] In some embodiments, along the thickness direction Z of the end cover 23 , the bottom surface 2311 of the recess 231 is closer to the current collecting member 24 than the inner surface 2332 of the cover 233 ; or, the bottom surface 2311 of the recess 231 is flush with the inner surface 2332 of the cover 233 .

[0130] If the bottom surface 2311 of the recess 231 is closer to the current collecting component 24 than the inner surface 2332 of the cover body 233, the recess 231 is recessed into the protrusion 234; if the bottom surface 2311 of the recess 231 is flush with the inner surface 2332 of the cover body 233, the bottom surface 2311 of the recess 231 and the inner surface 2332 of the cover body 233 are located in the same plane.

[0131] The above structure, on the one hand, increases the depth of the recess 231, thereby increasing the space of the recess 231 for accommodating the pressure relief mechanism 25; on the other hand, it makes the distance between the abutment surface 2341 of the protrusion 234 and the bottom surface 2311 of the recess 231 relatively small, so that the thickness of the connecting portion 232 is relatively small, which facilitates welding the connecting portion 232 and the current collecting component 24 from the outside of the end cover 23 (such as, through-welding connection), thereby improving the firmness of the connecting portion 232 and the current collecting component 24 after welding.

[0132] In some embodiments, the pressure relief mechanism 25 is entirely contained within the recess 231. The pressure relief mechanism 25 has no portion outside the recess 231 and does not occupy space outside the recess 231, further reducing the overall volume of the battery cell 20.

[0133] In some embodiments, please refer to Figure 6-Figure 8 A hole 2321 is provided on the connecting portion 232 , and the hole 2321 passes through two surfaces of the connecting portion 232 that are oppositely arranged along the thickness direction Z of the end cover 23 , and the pressure relief mechanism 25 covers the hole 2321 along the thickness direction Z of the end cover 23 .

[0134] The hole 2321 is a through-hole structure provided in the connecting portion 232 , and the hole 2321 can be provided at the center of the connecting portion 232 . In the embodiment where the pressure relief mechanism 25 is provided with the avoidance groove 251 , the hole 2321 is communicated with the avoidance groove 251 .

[0135] In the embodiment where the end cover 23 has the protrusion 234 , two surfaces of the connection portion 232 opposite to each other along the thickness direction Z of the end cover 23 are respectively the abutting surface 2341 of the protrusion 234 and the bottom surface 2311 of the recess 231 .

[0136] In this embodiment, the connection portion 232 is provided with a hole 2321 that passes through the connection portion 232. The provision of the hole 2321 can relieve stress generated when the connection portion 232 is welded to the current collecting member 24. The pressure relief mechanism 25 covers the hole 2321 along the thickness direction Z of the end cap 23. When the pressure relief mechanism 25 is actuated, the pressure inside the battery cell 20 can be released through the hole 2321.

[0137] In some embodiments, the first welding portion 27 extends along the circumference of the hole 2321 , which is located on the inner circumference of the welding portion and is used to inject electrolyte into the battery cell 20 . The electrolyte can be injected into the battery cell 20 through the hole 2321 .

[0138] The first welding portion 27 can be a closed structure extending along the circumference of the end cap 23, for example, the first welding portion 27 is an annular structure. The first welding portion 27 can also be a non-closed structure extending along the circumference of the end cap 23, for example, the first welding portion 27 is divided into multiple sections, and the multiple sections are arranged at intervals along the circumference of the end cap 23. Taking the first welding portion 27 as an annular structure as an example, the first welding portion 27 can be coaxially arranged with the channel 2321, so that the channel 2321 is located on the inner circumference of the first welding portion 27.

[0139] When the first welding portion 27 and the second welding portion 28 both extend along the circumference of the end cover 23, and the second welding portion 28 is located on the outer peripheral side of the first welding portion 27, the second welding portion 28, the first welding portion 27 and the channel 2321 are arranged in sequence from the outside to the inside in the radial direction of the channel 2321, that is, the second welding portion 28 is located on the outer peripheral side of the first welding portion 27, and the first welding portion 27 is located on the outer peripheral side of the channel 2321.

[0140] When electrolyte is injected into the battery cell 20 through the hole 2321, residual electrolyte may remain around the connection portion 232 on the hole 2321. If the pressure relief mechanism 25 and the end cap 23 are welded close to the hole 2321, the residual electrolyte on the connection portion 232 may cause the weld between the pressure relief mechanism 25 and the end cap 23 to become loose, resulting in a low weld quality rate. However, because the second weld portion 28 is located on the outer periphery of the first weld portion 27, the second weld portion 28 is further away from the hole 2321 than the first weld portion 27, which makes the weld position between the pressure relief mechanism 25 and the end cap 23 further away from the hole 2321. When welding the pressure relief mechanism 25 and the end cap 23, the residual electrolyte around the hole 2321 is less likely to affect the weld, ensuring a secure weld between the pressure relief mechanism 25 and the end cap 23 and improving the weld quality rate.

[0141] In some embodiments, please refer to Figure 9 , Figure 9 for Figure 6As shown in the structural schematic diagram of the current collecting component 24, the current collecting component 24 is provided with a first center hole 241 and a guide channel 242 for allowing electrolyte to enter the interior of the battery cell 20. The guide channel 242 is arranged around the first center hole 241. Along the thickness direction Z of the end cover 23, the first center hole 241 and the channel 2321 are arranged opposite to each other.

[0142] The first center hole 241 is a through-hole located at the center of the current collecting member 24. For example, if the current collecting member 24 is a disc, the axis of the first center hole 241 coincides with the axis of the current collecting member 24. The first center hole 241 and the channel 2321 are positioned opposite each other along the thickness direction Z of the end cap 23. The first center hole 241 and the channel 2321 can be coaxial, or the axis of the first center hole 241 can be slightly offset from the axis of the channel 2321. As long as the first center hole 241 and the channel 2321 are not completely offset in the radial direction of the first center hole 241, it should be understood that the first center hole 241 and the channel 2321 are positioned opposite each other along the thickness direction Z of the end cap 23.

[0143] The flow guiding channel 242 is a channel on the current collecting member 24 that is distinct from the first central hole 241 and is used to transport electrolyte. The flow guiding channel 242 can be independent of the first central hole 241 or can be connected to the first central hole 241. There can be one or more flow guiding channels 242. For example, if there are multiple flow guiding channels 242, the multiple flow guiding channels 242 can be distributed around the first central hole 241.

[0144] Exemplarily, the electrode assembly 22 has a second central hole 223. Along the thickness direction Z of the end cap 23, the first central hole 241 is disposed opposite the second central hole 223. For example, in the case of a wound structure of the electrode assembly 22 formed by winding a positive electrode sheet, a separator, and a negative electrode sheet, the second central hole 223 is formed at the winding core of the main body.

[0145] In this embodiment, since the first center hole 241 and the channel 2321 are arranged relative to each other along the thickness direction Z of the end cover 23, and the guide channel 242 is arranged around the first center hole 241, in the process of injecting electrolyte into the battery cell 20 through the channel 2321, the electrolyte can not only flow into the battery cell 20 along the first center hole 241, but also flow into the battery cell 20 along the guide channel 242, thereby improving the injection efficiency and allowing the electrolyte to better infiltrate the electrode assembly 22.

[0146] In some embodiments, please refer to Figure 9 The flow guide channel 242 includes a flow guide hole, which passes through two surfaces of the collecting component 24 that are relatively arranged along the thickness direction Z of the end cover 23; and / or, the flow guide channel 242 includes a flow guide groove, which is arranged on at least one surface of the collecting component 24 in the thickness direction Z of the end cover 23.

[0147] The guide groove is arranged on at least one surface of the current collecting component 24 in the thickness direction Z of the end cover 23. The guide groove may be provided only on the surface of the current collecting component 24 facing the electrode assembly 22, or only on the surface of the current collecting component 24 facing the end cover 23, or both on the surface of the current collecting component 24 facing the end cover 23 and on the surface facing the electrode assembly 22.

[0148] In this embodiment, if the flow guide channel 242 is a flow-guiding hole that penetrates both surfaces of the current collecting member 24 along the thickness direction Z of the end cap 23, the electrolyte entering through the hole 2321 can quickly flow from the side of the current collecting member 24 facing the end cap 23 to the side facing away from the end cap 23 through the flow-guiding hole. If the flow guide channel 242 is a flow-guiding groove provided on the surface of the current collecting member 24, the electrolyte entering through the hole 2321 can flow laterally along the flow-guiding groove, which facilitates the electrolyte to enter the electrode assembly 22 and infiltrate the electrode sheets.

[0149] An embodiment of the present application provides a battery 100 , comprising a housing 10 and a battery cell 20 provided in any one of the above embodiments. The housing 10 is used to accommodate the battery cell 20 .

[0150] An embodiment of the present application provides an electrical device, including a battery 100 and the battery 100 provided by any embodiment.

[0151] In addition, please refer to Figure 3 and Figure 4 The embodiment of the present application provides a cylindrical battery, including a housing 21, an electrode assembly 22, an end cap 23, a current collecting member 24, and a pressure relief mechanism 25. The housing 21 has openings at opposite ends. One end cap 23 covers the top opening of the housing 21, and the other end cap 23 covers the bottom opening of the housing 21. The end cap 23 at the top of the housing 21 is provided with an electrode terminal 26. The electrode assembly 22 has a positive electrode tab 221 and a negative electrode tab 222. The positive electrode tab 221 is connected to the electrode terminal 26 via a current collecting member 24, and the negative electrode tab 222 is connected to the end cap 23 at the bottom of the housing 21 via another current collecting member 24. The pressure relief mechanism 25 is provided on the end cap 23 at the bottom of the housing 21. Among them, the end cover 23 at the bottom of the shell 21 is provided with a recess 231 on the side facing away from the electrode assembly 22, and the recess 231 is used to accommodate at least a part of the pressure relief mechanism 25. The end cover 23 at the bottom of the shell 21 forms a connecting portion 232 in the area where the recess 231 is provided, and the connecting portion 232 is used to be welded with the current collecting component 24 and form a first welding portion 27. The pressure relief mechanism 25 covers the first welding portion 27 along the thickness direction Z of the end cover 23.

[0152] In such a cylindrical battery, since the end cover 23 forms a connecting portion 232 in the area where the recess 231 is provided, the connecting portion 232 is welded to the current collecting member 24 to form a first welding portion 27, and the pressure relief mechanism 25 covers the first welding portion 27, so that the pressure relief mechanism 25 and the first welding portion 27 are distributed in the thickness direction Z of the end cover 23. The size of the pressure relief mechanism 25 in the thickness direction Z perpendicular to the end cover 23 will not be restricted by the first welding portion 27. The size of the recess 231 and the pressure relief mechanism 25 can be enlarged as needed, which is beneficial to improving the pressure relief capacity of the pressure relief mechanism 25 and enhancing the safety of the battery cell 20.

[0153] Please refer to Figure 10 , Figure 10 This is a flow chart of a method for manufacturing a battery cell 20 provided in some embodiments of the present application. The present application provides a method for manufacturing a battery cell 20, and the manufacturing method includes:

[0154] S100: Providing a housing 21 having an opening;

[0155] S200: Providing an electrode assembly 22;

[0156] S300: providing an end cover 23, wherein the end cover 23 is provided with a recess 231, and a connecting portion 232 is formed in the region where the recess 231 is provided; providing a current collecting member 24;

[0157] S400: providing a pressure relief mechanism 25, the pressure relief mechanism 25 being configured to be actuated when the pressure or temperature inside the battery cell 20 reaches a threshold value, so as to relieve the pressure inside the battery cell 20;

[0158] S500: accommodating the electrode assembly 22 in the housing 21;

[0159] S600: Connecting the current collecting member 24 to the electrode assembly 22;

[0160] S700: Cover the end cover 23 with the opening so that the recess 231 is located on the side of the end cover 23 facing away from the electrode assembly 22;

[0161] S800: Welding the connection portion 232 to the current collecting member 24 to form a first welding portion 27;

[0162] S900 : Install the pressure relief mechanism 25 in the end cover 23 so that at least a portion of the pressure relief mechanism 25 is accommodated in the recess 231 , and the pressure relief mechanism 25 covers the first welding portion 27 along the thickness direction Z of the end cover 23 .

[0163] In the above method, the order of step S100, step S200, step S300 and step S400 is not limited. For example, step S400 may be performed first, then step S300, then step S200, and finally step S100.

[0164] It should be noted that the relevant structure of the battery cell 20 manufactured by the manufacturing method provided by the above embodiment can refer to the battery cell 20 provided by the above embodiments, and will not be repeated here.

[0165] Please refer to Figure 11 , Figure 11 This is a schematic block diagram of a manufacturing device 2000 for a battery cell 20 provided in some embodiments of the present application. The embodiments of the present application also provide a manufacturing device 2000 for a battery cell 20, and the manufacturing device 2000 includes a first providing device 2100, a second providing device 2200, a third providing device 2300, a fourth providing device 2400, a fifth providing device 2500 and an assembling device 2600.

[0166] The first providing device 2100 is used to provide a housing 21 having an opening. The second providing device 2200 is used to provide an electrode assembly 22. The third providing device 2300 is used to provide an end cap 23, which is provided with a recess 231 and has a connection portion 232 formed in the area where the recess 231 is provided. The fourth providing device 2400 is used to provide a current collecting member 24. The fifth providing device 2500 is used to provide a pressure relief mechanism 25, which is activated when the pressure or temperature inside the battery cell 20 reaches a threshold value to relieve the pressure inside the battery cell 20. The assembly device 2600 is used to accommodate the electrode assembly 22 in the shell 21; the assembly device 2600 is also used to connect the current collecting component 24 to the electrode assembly 22; the assembly device 2600 is also used to cover the end cover 23 on the opening so that the recess 231 is located on the side of the end cover 23 away from the electrode assembly 22; the assembly device 2600 is also used to weld the connecting portion 232 to the current collecting component 24 to form a first welding portion 27; the assembly device 2600 is also used to install the pressure relief mechanism 25 in the end cover 23 so that at least a portion of the pressure relief mechanism 25 is accommodated in the recess 231, so that the pressure relief mechanism 25 covers the first welding portion 27 along the thickness direction Z of the end cover 23.

[0167] It should be noted that the relevant structures of the battery cells 20 manufactured by the manufacturing equipment 2000 provided by the above embodiment can refer to the battery cells 20 provided by the above embodiments, and will not be repeated here.

[0168] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0169] The above embodiments are intended only to illustrate the technical solutions of this application and are not intended to limit this application. Those skilled in the art will appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this application are intended to be within the scope of protection of this application.

Claims

1. A battery cell, characterized in that: include: a housing having an opening; an electrode assembly, configured to be accommodated in the housing; an end cover, used to cover the opening, wherein the shape of the end cover is adapted to the shape of the housing; a current collecting member, located on a side of the electrode assembly facing the end cap, the current collecting member being used to connect the electrode assembly and the end cap to achieve electrical connection between the electrode assembly and the end cap; a pressure relief mechanism, disposed on the end cover, configured to be actuated when the pressure or temperature inside the battery cell reaches a threshold value to relieve the pressure inside the battery cell; The end cap is provided with a recess on a side facing away from the electrode assembly, the recess being used to accommodate at least a portion of the pressure relief mechanism. The end cap forms a connecting portion in the region where the recess is provided, the connecting portion being used to be welded to the current collecting member to form a first welding portion, and the pressure relief mechanism covers the first welding portion along the thickness direction of the end cap. The end cap comprises: a cover body, configured to be connected to the housing, the cover body having an outer surface and an inner surface disposed opposite to each other along the thickness direction, the inner surface facing the current collecting member, and the recessed portion being recessed from the outer surface in a direction facing the current collecting member; A protrusion is provided on the inner surface and is located at a position corresponding to the cover body and the recess. The protrusion has a supporting surface for abutting against the current collecting component. The portion of the end cover located between the supporting surface and the bottom surface of the recess is the connecting portion. Along the thickness direction, the bottom surface is closer to the current collecting component than the inner surface; or, the bottom surface is flush with the inner surface.

2. The battery cell according to claim 1, wherein: The pressure relief mechanism and the end cover are welded to form a second welding portion. Along the thickness direction, a projection of the second welding portion does not overlap with a projection of the first welding portion.

3. The battery cell according to claim 2, characterized in that: The first welding portion and the second welding portion both extend along the circumferential direction of the end cover, and the second welding portion is located on the outer circumferential side of the first welding portion.

4. The battery cell according to claim 2, characterized in that: Along the circumference of the end cover, the second welding portions and the first welding portions are arranged alternately.

5. The battery cell according to claim 1, characterized in that A side of the pressure relief mechanism facing the connecting portion is provided with an avoidance groove, and the avoidance groove is used to avoid the first welding portion.

6. The battery cell according to claim 5, characterized in that The pressure relief mechanism comprises: a base portion, configured to be welded to the end cover to form a second welding portion; A pressure relief portion is used to actuate when the pressure or temperature inside the battery cell reaches a threshold value to release the pressure inside the battery cell. The pressure relief portion is connected to the inner circumferential surface of the base, and the pressure relief portion covers the first welding portion along the thickness direction. The pressure relief portion and the base jointly define the avoidance groove.

7. The battery cell according to claim 6, characterized in that The thickness of the pressure relief portion is smaller than that of the base portion.

8. The battery cell according to claim 6, characterized in that The base portion and the connecting portion are welded to form the second weld portion; or the outer peripheral surface of the base portion and the inner peripheral surface of the recessed portion are welded to form the second weld portion.

9. The battery cell according to any one of claims 1 to 8, characterized in that: The pressure relief mechanism is entirely accommodated in the recess.

10. The battery cell according to any one of claims 1 to 8, characterized in that: The connecting portion is provided with a hole, the hole passing through two surfaces of the connecting portion that are opposite to each other along the thickness direction, and the pressure relief mechanism covers the hole along the thickness direction.

11. The battery cell according to claim 10, characterized in that The first welding portion extends along the circumference of the hole, the hole is located on the inner circumference of the first welding portion, and the hole is used to inject electrolyte into the battery cell.

12. The battery cell according to claim 11, wherein The current collecting component is provided with a first central hole and a guide channel for the electrolyte to enter the battery cell. The guide channel is arranged around the first central hole. Along the thickness direction, the first central hole and the channel are arranged opposite to each other.

13. The battery cell according to claim 12, characterized in that: The flow guiding channel comprises a flow guiding hole, and the flow guiding hole penetrates two surfaces of the flow collecting component that are opposite to each other along the thickness direction; and / or The flow guiding channel includes a flow guiding groove, and the flow guiding groove is provided on at least one surface of the current collecting member in the thickness direction.

14. A battery, characterized in that: include: The battery cell according to any one of claims 1 to 13; The box is used to accommodate the battery cells.

15. An electrical device, characterized in that: Comprising the battery of claim 14.

16. A method for manufacturing a battery cell, characterized in that: The manufacturing method comprises: providing a housing having an opening; providing an electrode assembly; Providing an end cap, wherein the end cap is provided with a recess, and the end cap forms a connecting portion in an area where the recess is provided; providing a current collecting component; Providing a pressure relief mechanism, the pressure relief mechanism being configured to be actuated when the pressure or temperature inside the battery cell reaches a threshold value to relieve the pressure inside the battery cell; accommodating the electrode assembly in the housing; connecting the current collecting member to the electrode assembly; Covering the end cover with the opening so that the recess is located on a side of the end cover facing away from the electrode assembly; welding the connecting portion and the current collecting member to form a first welding portion; The pressure relief mechanism is installed in the end cover so that at least a portion of the pressure relief mechanism is accommodated in the recess, and the pressure relief mechanism covers the first welding portion along the thickness direction of the end cover, wherein the end cover comprises: a cover body, configured to be connected to the housing, the cover body having an outer surface and an inner surface disposed opposite to each other along the thickness direction, the inner surface facing the current collecting member, and the recessed portion being recessed from the outer surface in a direction facing the current collecting member; A protrusion is provided on the inner surface and is located at a position corresponding to the cover body and the recess. The protrusion has a supporting surface for abutting against the current collecting component. The portion of the end cover located between the supporting surface and the bottom surface of the recess is the connecting portion. Along the thickness direction, the bottom surface is closer to the current collecting component than the inner surface; or, the bottom surface is flush with the inner surface.

17. A battery cell manufacturing device, characterized in that: The manufacturing equipment includes: A first providing device is used to provide a housing having an opening; a second providing device for providing an electrode assembly; A third providing device is used to provide an end cap, wherein the end cap is provided with a recess, and the end cap forms a connecting portion in an area where the recess is provided; A fourth providing device, for providing a current collecting member; A fifth providing device is configured to provide a pressure relief mechanism, wherein the pressure relief mechanism is configured to be actuated when the pressure or temperature inside the battery cell reaches a threshold value to relieve the pressure inside the battery cell; Assembly device for: accommodating the electrode assembly in the housing; connecting the current collecting member to the electrode assembly; Covering the end cover with the opening so that the recess is located on a side of the end cover facing away from the electrode assembly; welding the connecting portion and the current collecting member to form a first welding portion; The pressure relief mechanism is installed in the end cover so that at least a portion of the pressure relief mechanism is accommodated in the recess, and the pressure relief mechanism covers the first welding portion along the thickness direction of the end cover, wherein the end cover comprises: a cover body, configured to be connected to the housing, the cover body having an outer surface and an inner surface disposed opposite to each other along the thickness direction, the inner surface facing the current collecting member, and the recessed portion being recessed from the outer surface in a direction facing the current collecting member; A protrusion is provided on the inner surface and is located at a position corresponding to the cover body and the recess. The protrusion has a supporting surface for abutting against the current collecting component. The portion of the end cover located between the supporting surface and the bottom surface of the recess is the connecting portion. Along the thickness direction, the bottom surface is closer to the current collecting component than the inner surface; or, the bottom surface is flush with the inner surface.

Images