Battery cell, battery, and electrical device

Abstract

The present application relates to the technical field of batteries. Provided are a battery cell, a battery and an electrical device. The battery cell comprises an electrode assembly and a current collection member, the electrode assembly comprising an electrode main body and tabs provided at the ends of the electrode main body; the current collection member is provided on a tab, and part of the outer edge portion of the current collection member coincides with the outer edge portion of the tab, such that part of the tab is exposed outside. In the battery cell provided by the present application, the outline dimension of the current collection member is smaller than that of the tab, such that the current collection member does not fully cover the tab. Thus, during laser welding of the current collection member and the tab, a laser beam can be incident laterally, so as to form a small acute angle with the plane where the tab is located, thereby lowering the probability of separator damage caused by the laser beam being vertically incident on the plane where the tab is located, and improving the yield of electrode assembly manufacturing.

Description

Battery cells, batteries and electrical equipment

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on October 26, 2023, with application number 202322882345.1 and invention name “Battery Cell, Battery and Electrical Equipment”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of battery technology, and in particular provides a battery cell, a battery, and an electrical device. Background Art

[0003] With the development of new energy technologies, batteries are being used more and more widely, for example, in mobile phones, laptops, electric vehicles, etc.

[0004] As an energy storage element, a battery cell generally outputs electrical energy through an electrochemical reaction between an electrode assembly and an electrolyte. In a battery cell, the end cap and the electrode assembly can be electrically connected through a current collecting member. Typically, the current collecting member and the electrode lug of the electrode assembly are connected by welding, and the welding direction of the welding device (the transmission direction of the welding laser) is perpendicular or approximately perpendicular to the current collecting member. In this way, it is difficult to avoid the diaphragm of the electrode assembly during the welding process, and the electrode assembly is prone to short circuiting. Technical issues

[0005] The purpose of this application is to provide a battery cell, a battery and an electrical device, aiming to solve the problem that the existing battery cells are prone to causing electrode short circuits during the manufacturing process. Technical Solutions

[0006] To achieve the above objectives, the technical solution adopted in this application is:

[0007] In a first aspect, an embodiment of the present application provides a battery cell, comprising:

[0008] An electrode assembly, the electrode assembly comprising an electrode body and an electrode tab provided at an end of the electrode body;

[0009] A current collecting member is placed on the tab, and an outer edge of a portion of the current collecting member overlaps with an outer edge of the tab, so that a portion of the tab is exposed to the outside.

[0010] In some embodiments, at least a portion of the outer edge of the current collecting member is recessed inward to form a notch structure.

[0011] In some embodiments, the current collecting component includes a base, an outer edge portion of the base is recessed inward to form the notch structure, and the tab can pass through the notch structure to the outside.

[0012] In some embodiments, the current collecting component includes a base and a stacked body, the base is placed on the tab, and an outer edge of the base and / or an outer edge of the stacked body is recessed inward to form the notch structure.

[0013] In some embodiments, the outer contour of the base is the same as the outer contour of the tab, and the base covers the tab, and the outer edge of the stack is recessed inward to form the notch structure.

[0014] In some embodiments, the geometric center of the current collecting member is colinear with the winding center axis of the electrode body, and the notch structure is recessed inwardly to the geometric center of the current collecting member.

[0015] In some embodiments, a projection of one of the outer edge portions of the current collecting member on the end portion of the electrode body is close to a winding center axis of the electrode body.

[0016] In some embodiments, a projection of an outer edge of the current collecting member on the electrode tab coincides with a winding center axis of the electrode body.

[0017] In a second aspect, an embodiment of the present application provides a battery comprising the battery cell described above.

[0018] In a third aspect, an embodiment of the present application provides an electrical device comprising the battery described above.

[0019] The beneficial effect of the battery cell provided by the embodiment of the present application is that: in the battery cell provided by the present application, the outer contour size of the current collecting component is smaller than the outer contour size of the pole tab, and the current collecting component fails to completely cover the pole tab, so that part of the pole tab is exposed. Therefore, when the current collecting component is laser-welded to the pole tab, the laser beam can be injected from the side, that is, at a smaller acute angle to the plane where the pole tab is located, so as to reduce the probability of damage to the diaphragm caused by the laser beam being vertically injected into the plane where the pole tab is located, thereby improving the yield rate of manufacturing electrode assemblies.

[0020] It can be understood that the beneficial effects of the second and third aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0022] FIG1 is a schematic structural diagram of an electrical device provided in an embodiment of the present application;

[0023] FIG2 is a schematic diagram of the structure of a battery provided in an embodiment of the present application;

[0024] FIG3 is a schematic structural diagram of a battery cell provided in an embodiment of the present application;

[0025] FIG4 is a schematic structural diagram of a tab and a current collecting component provided in Example 1 of the present application;

[0026] FIG5 is a schematic structural diagram of a tab and a current collecting component provided in Example 2 of the present application;

[0027] FIG6 is a schematic structural diagram of a tab and a current collecting component provided in Example 3 of the present application;

[0028] FIG7 is a schematic structural diagram of a tab and a current collecting component provided in Example 4 of the present application;

[0029] FIG8 is an exploded view of an electrode assembly provided in Example 5 of the present application;

[0030] FIG9 is an exploded view of the electrode assembly provided in Example 6 of the present application.

[0031] Among them, the figure marks in the figure are: 10000, electrical equipment; 1000, controller; 2000, motor; 3000, battery; 3001, battery cell; 3002, battery case; 30021, first part; 30022, second part; 10, electrode assembly; 20, shell; 30, end cover; 11, electrode body; 12, tab; 40, current collecting component; 40a, notch structure; 41, substrate; 42, laminated body; winding center axis N.

[0032] Implementation Methods of the Application

[0033] The following describes in detail embodiments of the present application, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0034] In the description of this application, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0035] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0036] In this application, unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components or interactions between two components. Those skilled in the art will understand the specific meanings of these terms in this application based on specific circumstances.

[0037] As an energy storage element, a battery cell generally outputs electrical energy through an electrochemical reaction between an electrode assembly and an electrolyte. In a battery cell, the end cap and the electrode assembly can be electrically connected through a current collecting disc. Usually, the current collecting disc and the tabs of the electrode assembly are connected by laser welding. Specifically, the laser welding beam is incident in a direction perpendicular to the tabs or approximately perpendicular to the plane where the tabs are located to achieve the connection between the current collecting disc and the tabs. However, in order to improve the reliability of the welding connection between the two, the thickness of the current collecting disc is relatively thin, which can easily cause the current collector to be welded through and cause damage to the diaphragm, ultimately leading to a short circuit in the electrode assembly.

[0038] In view of this, the present application provides an electrode assembly, wherein at least part of the outer edge of the current collecting component does not overlap with the outer edge of the pole ear, that is, the outer contour size of the current collecting component is smaller than the outer contour size of the pole ear. In this way, the current collecting component fails to completely cover the pole ear, so that part of the pole ear is exposed to the outside. Then, when the current collecting component is laser welded to the pole ear, the laser beam can be injected from the side, that is, at a smaller acute angle to the plane where the pole ear is located, so as to reduce the probability of damage to the diaphragm caused by the laser beam being vertically injected into the plane where the pole ear is located, thereby improving the yield of manufacturing electrode assemblies.

[0039] 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 current collector. The current collector uncoated with the positive active material layer protrudes from the current collector coated with the positive active material layer. The current collectors uncoated with the positive active material layer, when stacked, serve as the positive electrode tabs. For ease of description, the term "tab" will be used to refer to the positive and / or negative electrode tabs.

[0040] In this application, battery cells include, but are not limited to, lithium-ion secondary battery cells, lithium-ion primary battery cells, lithium-sulfur battery cells, sodium-lithium-ion battery cells, sodium-ion battery cells, or magnesium-ion battery cells. Battery cells may be cylindrical, flat, rectangular, or other shapes. Battery cells are generally categorized into three types based on packaging: cylindrical, prismatic, and soft-pack battery cells.

[0041] The present embodiment provides a device 10000 that uses the battery cell 3001 as a power source and can be applied to electrical equipment such as vehicles, mobile phones, portable devices, laptop computers, ships, spacecraft, and power tools. The vehicle can be a fuel-powered vehicle, a gas-powered vehicle, or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle, or an extended-range vehicle. The spacecraft includes aircraft, rockets, space shuttles, and spacecraft. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys. Electric tools include metal cutting power tools, grinding power tools, assembly power tools, and ironwork power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers.

[0042] The battery cell 3001 described in the embodiment of the present application is not limited to the electrical equipment 10000 described above, but can also be applied to all devices using the battery cell 3001. However, for the sake of simplicity, the following embodiments are described using electric vehicles as an example.

[0043] For example, please refer to Figure 1, which is a schematic structural diagram of a vehicle in an embodiment of the present application. The vehicle can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 3000, a controller 1000 and a motor 2000 can be set inside the vehicle. The controller 1000 is used to control the battery 3000 to power the motor 2000. For example, a battery 3000 can be set at the bottom, front or rear of the vehicle. The battery 3000 can be used to power the vehicle. For example, the battery 3000 can be used as an operating power source for the vehicle and for the circuit system of the vehicle, for example, for the working power requirements during the start-up, navigation and operation of the vehicle. In another embodiment of the present application, the battery 3000 can not only be used as an operating power source for the vehicle, but also as a driving power source for the vehicle, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle.

[0044] The battery 3000 mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells 3001 to provide higher voltage and capacity. Referring to Figure 2, the battery 3000 may include multiple battery cells 3001. The number of battery cells 3001 and the connection between the battery cells 3001 can be set as needed to meet different power requirements. Specifically, multiple battery cells 3001 can be connected in series, in parallel, or in hybrid mode. Hybrid mode refers to a mixture of series and parallel modes so that the battery 3000 has a larger capacity or power. Optionally, multiple battery cells 3001 can first be connected in series, in parallel, or in hybrid mode to form a battery 3000 module, and multiple battery 3000 modules can then be connected in series, in parallel, or in hybrid mode to form a battery 3000. In other words, multiple battery cells can directly form a battery 3000, or they can first form a battery module, and then the battery module can form a battery 3000.

[0045] The battery 3000 also includes a battery case 3002, which has a storage space inside, and multiple battery cells are stored in the storage space. As shown in the figure, the battery case 3002 can include two parts, which are respectively referred to as the first part 30021 and the second part 30022. Please refer to Figure and Figure, which show the first part 30021 of the battery case 3002. The first part 30021 and the second part 30022 can be connected by snapping, bonding, etc. to form a storage space. Multiple battery cells are connected in parallel, series, or mixed and placed in the case formed by connecting the first part 30021 and the second part 30022. The shapes of the first part 30021 and the second part 30022 can be determined according to the shape of the combination of multiple battery cells.

[0046] The battery case 3002 is used to protect at least one battery cell, thereby reducing the impact of liquid or other foreign matter outside the battery 3000 on the charging or discharging of the at least one battery cell. The battery cell may be cylindrical, flat, rectangular, or in other shapes, and this embodiment of the application does not limit this. Battery cell packaging methods include, but are not limited to, cylindrical battery cells, prismatic battery cells, and soft-pack battery cells, and this embodiment of the application does not specifically limit this.

[0047] In addition, the battery 3000 may also include other structures, which will not be described in detail here. For example, the battery 3000 may also include a busbar. The busbar is used to achieve electrical connection between multiple battery cells, such as achieving parallel connection, series connection, or mixed connection between multiple battery cells. Specifically, the busbar can achieve electrical connection between battery cells by connecting the electrode terminals of the battery cells. Furthermore, the busbar can be fixedly connected to the electrode terminals of the battery cells by welding. Optionally, the busbar may include a conductive mechanism, and the electrical energy generated by the multiple battery cells can be further led out through the battery case 3002 through the conductive mechanism.

[0048] Each battery cell 3001 can be a lithium-ion battery cell, a lithium-sulfur battery cell, a sodium-ion battery cell, or a magnesium-ion battery cell, but is not limited thereto. The battery cell 3001 can be cylindrical, flat, rectangular, or in other shapes.

[0049] Please refer to Figure 3, which is a schematic diagram of the exploded structure of a battery cell 3001 provided in some embodiments of the present application. A battery cell 3001 is the smallest unit that makes up a battery 3000. As shown in Figure 3, a battery cell 3001 includes a housing 20, an end cap 30, an electrode assembly 10, electrode terminals, and other functional components.

[0050] The end cap 30 is a component that covers the opening of the housing 20 to isolate the internal environment of the battery cell 3001 from the external environment. The shape of the end cap 30 can be adapted to the shape of the housing 20 to match the housing 20. Optionally, the end cap 30 can be made of a material with a certain hardness and strength (such as an aluminum alloy). This prevents the end cap 30 from deforming when subjected to compression or collision, giving the battery cell 3001 greater structural strength and improved safety. Functional components such as electrode terminals can be provided on the end cap 30. The electrode terminals can be used to connect to the electrode assembly 10 to output or input electrical energy to the battery cell. In some embodiments, the end cap 30 can also be provided with a pressure relief mechanism for relieving internal pressure when the internal pressure or temperature of the battery cell 3001 reaches a threshold. The end cap 30 can also be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this embodiment of the present application does not impose any specific limitations on this. In some embodiments, an insulating member may be provided inside the end cap 30 to isolate the electrical connection components in the housing 20 from the end cap 30 to reduce the risk of short circuit. For example, the insulating member may be made of plastic, rubber, or the like.

[0051] The housing 20 is a component that cooperates with the end cap 30 to form the internal environment of the battery cell 3001. This internal environment can be used to accommodate the electrode assembly 10, electrolyte, and other components. The housing 20 and end cap 30 can be separate components. An opening can be provided in the housing 20, and the end cap 30 is placed over the opening to form the internal environment of the battery cell. Alternatively, the end cap 30 and housing 20 can be integrated. Specifically, the end cap 30 and housing 20 can form a common connection surface before other components are inserted into the housing. When the interior of the housing 20 needs to be enclosed, the end cap 30 is placed over the housing 20. The housing 20 can have a variety of shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism, etc. Specifically, the shape of the housing 20 can be determined based on the specific shape and size of the electrode assembly. The housing 20 can be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this embodiment of the present application does not impose any particular limitations on this.

[0052] The electrode assembly 10 is a component in the battery cell 3001 where electrochemical reactions occur. One or more electrode assemblies 10 may be contained in the housing 20. The electrode assembly 10 is mainly formed by winding or stacking positive and negative electrode sheets, and a separator is usually provided between the positive and negative electrode sheets. The portions of the positive and negative electrode sheets with active materials constitute the electrode body of the electrode assembly, and the portions of the positive and negative electrode sheets without active materials each constitute a tab. The positive tab and the negative tab may be located together at one end of the electrode body or respectively at both ends of the electrode body. During the charge and discharge process of the battery, the positive active material and the negative active material react with the electrolyte, and the tabs connect the electrode terminals to form a current loop.

[0053] With reference to FIG3 to FIG9 , FIG3 is an exploded view of a battery cell 3001 provided in some embodiments of the present application;

[0054] In a first aspect, an embodiment of the present application provides a battery cell 3001 including an electrode assembly 10 and a current collecting member 40 .

[0055] The electrode assembly 10 includes an electrode body 11 and a tab 12 provided at an end of the electrode body 11;

[0056] The current collecting member 40 is placed on the electrode tab 12 , and the outer edge of the current collecting member 40 overlaps with the outer edge of the electrode tab 12 , so that part of the electrode tab 12 is exposed to the outside.

[0057] As can be understood, the current collecting member 40 is the component that electrically connects the end caps of the battery cells to the tabs 12. The current collecting member 40 can have a variety of contours, such as circular, rectangular, triangular, elliptical, and irregular shapes. The shape of the current collecting member 40 can be adapted to the shape of the battery cell housing. For example, if the housing is cylindrical and the current collecting member 40 is circular, the current collecting member 40 can also be referred to as a collecting tray.

[0058] In the installed position, the current collecting member 40 is connected to both the tab 12 of the electrode assembly 10 and the end cap of the electrode assembly 10. It should be noted that the tab 12 of the electrode assembly 10 connected to the current collecting member 40 can be either a positive tab or a negative tab.

[0059] The outer edge of the current collecting member 40 refers to the edge of the current collecting member 40 and also constitutes the outer contour of the current collecting member 40. The current collecting member 40 may have one or more outer edge portions. For example, a circular or elliptical current collecting member 40 may have only one outer edge portion, while a triangular or rectangular current collecting member 40 may have multiple outer edge portions. If the outer edge of part of the current collecting member 40 overlaps the outer edge of the tab 12, it means that the current collecting member 40 does not completely cover the tab 12, leaving part of the tab 12 exposed to the outside, allowing for welding using a side-entry laser beam.

[0060] For example, as shown in Figure 5, the current collecting component 40 is a circular structure, and the outer edge of the current collecting component 40 of the circular structure is tangent to the outer edge of the pole lug 12, so that a part of the pole lug 12 can be exposed to the outside from the uncovered area of ​​the current collecting component 40 to meet the lateral injection of the welding laser beam.

[0061] For example, as shown in Figure 6, the current collecting component 40 has a wavy outer edge structure, and one of the outer edges of the current collecting component 40 coincides with the outer edge of the pole lug 12. Similarly, a portion of the pole lug 12 can be exposed to the outside from the uncovered area of ​​the current collecting component 40 to meet the lateral entry of the welding laser beam.

[0062] For example, as shown in Figure 7, the current collecting component 40 is a rectangular structure, and the current collecting component 40 with the rectangular structure is set in the middle of the pole lug 12, so that the part where the outer edge of the current collecting component 40 overlaps with the outer edge of the pole lug 12 is the vertex of the current collecting component 40. Then, the pole lug 12 can be exposed to the outside from the area not covered by the current collecting component 40 to meet the lateral injection of the welding laser beam.

[0063] The battery cell provided in the present application is configured such that the outer edge of the current collecting component 40 is overlapped with the outer edge of the pole lug 12, so that the outer contour size of the current collecting component 40 is smaller than the outer contour size of the pole lug 12, so that part of the pole lug 12 is exposed. In this way, the current collecting component 40 cannot completely cover the pole lug 12. Then, when the current collecting component 40 is laser-welded to the pole lug 12, the laser beam can be injected from the side, that is, the incident direction of the laser beam forms a smaller acute angle with the plane where the pole lug 12 is located, so as to reduce the probability of damage to the diaphragm caused by the laser beam being vertically injected into the plane where the pole lug 12 is located, thereby improving the yield of manufacturing the electrode assembly 10; at the same time, the overall material consumption of the incoming current collecting component 40 can be reduced, which can reduce the material cost of the current collecting component 40 to a certain extent.

[0064] Referring to FIG. 4 , in some embodiments, at least a portion of the outer edge of the current collecting member 40 is recessed inward to form a notch structure 40 a .

[0065] It can be understood that the shape of the notch structure 40a includes but is not limited to semicircular, circular, rectangular, strip, etc.; the number of notch structures 40a can be one or more, and the setting position of the notch structure 40a can be any position on the outer edge of the current collecting component 40.

[0066] The tab 12 can be exposed to the outside through the notch structure 40 a , and during laser welding, the laser beam can be injected laterally into the notch structure 40 a to reduce the probability of damaging the diaphragm.

[0067] For example, as shown in Figure 4, the initial outer contour of the current collecting member 40 is circular. After the notch structure 40a is formed at its outer edge, the final outer contour of the current collecting member 40 is three-quarter circular. During laser welding, the welding trajectory of the laser beam follows the outer edge of the notch structure 40a and the curved outer edge of the current collecting member 40. Furthermore, when the curved outer edge of the current collecting member 40 coincides with the outer edge of the tab 12, the laser beam can be incident laterally at the outer edge of the notch structure 40a. That is, the incident direction of the laser beam forms a small acute angle with the plane of the tab 12.

[0068] For example, the initial outer contour of the current collecting member 40 is circular, and the number of notch structures 40a is two, and they are symmetrically arranged about the center point of the current collecting member 40. Similarly, during laser welding, the welding trajectory of the laser beam is along the outer edge of each notch structure 40a and the arc-shaped outer edge of the current collecting member 40. Moreover, when the arc-shaped outer edge of the current collecting member 40 coincides with the outer edge of the tab 12, the laser beam at the outer edge of each notch structure 40a can be incident laterally, that is, the incident direction of the laser beam forms a small acute angle with the plane of the tab 12.

[0069] Referring to FIG. 8 , in some embodiments, the current collecting member 40 includes a base 41 , the outer edge of the base 41 is recessed inward to form a notch structure 40 a , and the tab 12 can pass through the notch structure 40 a to reach the outside.

[0070] It can be understood that this type of current collecting component 40 is a single-layer sheet structure, and the notch structure 40a formed on the outer edge of the base 41 penetrates the base 41 along the thickness direction of the base 41. Therefore, when the base 41 is placed on the pole ear 12, part of the pole ear 12 can pass through the notch structure 40a to the outside.

[0071] The single-layer current collecting component 40 with only the base 41 is thinner and is suitable for welding scenarios with lower laser beam intensity. At the same time, the thinner current collecting component 40 is more conducive to welding the tabs 12 and reducing the probability of diaphragm damage.

[0072] For example, as shown in FIG8 , the initial outer contour of the current collecting member 40 is a circle. After the notch structure 40 a is formed at the outer edge thereof, the final outer contour of the current collecting member 40 is three-quarters of a circle.

[0073] 9 , in some embodiments, the current collecting member 40 includes a base 41 and a stack 42 , the base 41 being placed on the tab 12 , and the outer edge of the base 41 and / or the outer edge of the stack 42 being recessed inward to form a notch structure 40 a .

[0074] It can be understood that this type of current collecting component 40 is a layered structure with two or more layers. For example, a layer of laminate 42 is provided on the base 41 to form a two-layered structure, or a plurality of laminates 42 are provided on the base 41 to form a multi-layered structure. Here, the connection method between the base 41 and the laminate 42 includes but is not limited to one-piece molding, welding, plug-in connection, threaded connection and riveting, etc. At the same time, the materials of the base 41 and the laminate 42 can be the same or different. For example, the material of the base 41 is the same as that of the tab 12, and the material of the laminate 42 is the same as that of the end cover of the battery cell. Therefore, when the base 41 is connected to the tab 12 by welding, and when the end cover of the battery cell is connected to the laminate 42, the same material can optimize the stability of the welded connection.

[0075] Furthermore, the notch structure 40a can be selectively provided on the outer edge of the substrate 41; or on the outer edge of the laminate 42; or, the outer edges of both the substrate 41 and the laminate 42 are recessed inward to form the notch structure 40a. It should be noted that when the notch structure 40a is formed on the substrate 41, the laminate 42 should be offset from the notch structure 40a so that the notch structure 40a is exposed, thereby meeting the welding requirement of the laser beam entering from the side. Furthermore, when the notch structure 40a is provided on both the substrate 41 and the laminate 42, the projections of the notch structure 40a on the substrate 41 and the notch structure 40a on the laminate 42 on the tab 12 should overlap, so that each notch structure 40a is exposed, thereby meeting the welding requirement of the laser beam entering from the side.

[0076] With such a configuration, the multi-layered current collecting component 40 has a larger flow cross section and a higher flow performance. At the same time, by providing the notch structure 40a to meet the welding requirements of the laser beam entering from the side, the probability of the diaphragm being damaged is reduced.

[0077] 9 , in a specific embodiment, the outer contour of the base 41 is the same as that of the tab 12 , and the base 41 covers the tab 12 , and the outer edge of the laminate 42 is recessed inward to form a notch structure 40 a .

[0078] It is understood that the current collecting member 40 has a two-layer structure. The outer contour of the base 41 is the same as the outer contour of the tab 12, and the tab 12 is covered. For example, if the tab 12 is circular, the base 41 is also circular. The outer contour of the laminate 42 can be the same as or different from the outer contour of the base 41. For example, if the base 41 is circular, then the initial outer contour of the laminate 42 can also be circular.

[0079] Furthermore, when the notch structure 40a is formed in the laminate 42, the outer edge formed by the notch structure 40a is away from the outer edge of the tab 12, that is, the outer edge of the laminate 42 of the current collecting member 40 where the notch structure 40a is located does not overlap with the outer edge of the tab 12. Therefore, when the base 41 is positioned on the tab 12, the outer edge of the base 41 can optionally be selected to completely overlap with the outer edge of the tab 12, that is, completely cover the outer edge of the tab 12.

[0080] For example, as shown in Figure 9, the outer contour of the base 41 of the current collecting component 40 is circular, which is compatible with the outer shape of the tab 12. The initial outer contour of the stack 42 is circular. After the notch structure 40a is formed at its outer edge, the final outer contour of the stack 42 is three-quarters circular.

[0081] Referring to FIG. 8 , in some embodiments, the geometric center of the current collecting member 40 is collinear with the winding center axis N of the electrode body 11 , and the notch structure 40 a is recessed inwardly to the geometric center of the current collecting member 40 .

[0082] It is understood that when the current collecting member 40 has a regular geometric shape, such as a circle, square, or ellipse, the geometric center of the current collecting member 40 is the center of the circle, the intersection of the diagonals of the square, and the center of the ellipse. When the current collecting member 40 has an irregular geometric shape, the geometric center of the current collecting member 40 is the geometric center of gravity.

[0083] The electrode body 11 is formed by winding the electrode sheets and then placing them in the shell of the battery cell. Therefore, the winding center axis N of the electrode body 11 is collinear or substantially collinear with the central axis of the shell.

[0084] The notch structure 40a is recessed inward to the geometric center of the current collecting component 40, that is, recessed to the winding center axis N of the electrode body 11. Therefore, the outer edge of the notch structure 40a is close to the winding center axis N of the electrode body 11. When laser welding is performed, the welding trajectory extends along the outer edge of the notch structure 40a, and also extends from the inner circle to the outer circle of the electrode body 11.

[0085] Battery polarization refers to the phenomenon in which the potential of a battery deviates from its equilibrium potential when current flows through it. When the weld path between the current collecting member 40 and the tab 12 overlaps, or substantially overlaps, with the winding path of the electrode body 11, either single-layer or multi-layer, battery polarization occurs in the battery cell. To improve battery polarization, the weld path between the current collecting member 40 and the tab 12 extends from the inner to the outer coil of the electrode body 11. This allows the current collecting member 40 to maintain a weld connection with each coil layer, increasing the flow area.

[0086] Here, the notch structure 40a is recessed inward to the geometric center of the current collecting component 40. The outer edge of the notch structure 40a may be close to but not intersecting with the winding center axis N of the electrode body 11, or the outer edge of the notch structure 40a may intersect with the winding center axis N of the electrode body 11.

[0087] For example, as shown in Figure 4, the initial outer contour of the current collecting component 40 is circular, and the outer contour of the electrode tab 12 is also circular. After the notch structure 40a is formed at the outer edge of the current collecting component 40, the final outer contour of the current collecting component 40 is three-quarters circular, and the projection of the outer edge of the notch structure 40a on the electrode tab 12 extends from the inner circle of the electrode body 11 to the outer circle.

[0088] Referring to FIG. 9 , in some embodiments, a projection of one outer edge portion of the current collecting member 40 on the end portion of the electrode body 11 is close to the winding center axis N of the electrode body 11 .

[0089] It can be understood that the end of the electrode body 11 refers to the end of the electrode sheet that forms a columnar structure or a columnar structure after winding. Usually, the pole tab 12 and the current collecting member 40 are arranged on the end of the electrode body 11, and the pole tab 12 needs to completely cover the end of the electrode body 11 in the assembly process. Then, the winding center axis N of the electrode body 11 and the center line of the pole tab 12 coincide with each other, and the projection of the outer edge of the current collecting member 40 on the end of the electrode body 11 is close to the winding center axis N of the electrode body 11, that is, the projection of the outer edge of the current collecting member 40 on the end of the electrode body 11 is also located at the center line of the pole tab 12. Then, the welding trajectory of the current collecting member 40 and the pole tab 12 also extends from the inner circle of the electrode body 11 to the outer circle, which can also improve the battery polarization phenomenon.

[0090] Here, according to the outer contour of the current collecting member 40, the current collecting member 40 may have only one outer edge portion, for example, the current collecting member 40 has a circular structure or an elliptical structure; or, the current collecting member 40 may have multiple outer edges, for example, the current collecting member 40 has a triangular structure or a rectangular structure.

[0091] For example, the current collecting member 40 is a circular structure, and the arc-shaped outer edge of the current collecting member 40 is located at the winding center axis N of the electrode body 11, that is, the arc-shaped outer edge of the current collecting member 40 is close to the projection on the tab 12, and even intersects with the winding center axis N of the electrode body 11.

[0092] For example, as shown in the figure, the current collecting component 40 is a triangular structure, and one of the outer edges of the current collecting component 40 is located at the winding center axis N of the electrode body 11, that is, one of the outer edges of the current collecting component 40 is close to the projection on the electrode tab 12, and even intersects with the winding center axis N of the electrode body 11.

[0093] Referring to FIG. 9 , in a specific embodiment, the projection of the outer edge of the current collecting member 40 on the electrode tab 12 coincides with the winding center axis N of the electrode body 11 .

[0094] It can be understood that the projection of the outer edge of the current collecting component 40 on the pole tab 12 coincides with the winding center axis N of the electrode body 11. Then, the welding trajectory of the current collecting component 40 and the pole tab 12 extends from the innermost circle of the electrode body 11 to the outer circle, thereby maximizing the electrical connection between the various layers of the electrode body 11 and the current collecting component 40, and can greatly improve the battery polarization phenomenon.

[0095] Referring to Figures 4 and 8, the present application provides a specific embodiment in which a battery cell includes an electrode assembly 10 and a current collecting member 40. The electrode assembly 10 includes an electrode body 11 and a tab 12 provided at the end of the electrode body 11; the current collecting member 40 is placed on the tab 12, and the outer edge of the current collecting member 40 is recessed inward to form a notch structure 40a. The electrode body 11 is wound to form a columnar structure, and the tab 12 located at the end of the electrode body 11 is a circular structure. The current collecting member 40 includes a base 41, which is also a circular structure in its initial state. After the notch structure 40a is formed, the current collecting member 40 forms a three-quarter circular structure. In this way, the tab 12 can be exposed to the outside through the notch structure 40a. Therefore, during the welding process, the welding requirement of the welding beam entering from the side is met.

[0096] In addition, the projection of the outer edge of the notch structure 40a on the tab 12 intersects with the winding center axis N of the electrode body 11. In this way, the welding track between the current collecting component 40 and the tab 12 is from the winding center axis N of the electrode body 11 to the outer circle, which effectively improves the problem of battery polarization.

[0097] Please refer to Figure 9. The present application also provides another specific embodiment, which is different from the above embodiment in that the current collecting component 40 includes a base 41 and a stacked body 42 stacked on the base 41. The base 41 is provided on the tab 12 and completely covers the tab 12. The outer contour size of the stacked body 42 is smaller than the outer contour size of the base 41. The outer edge of the stacked body 42 is recessed inward to form a notch structure 40a. Similarly, after the notch structure 40a is formed, the stacked body 42 forms a three-quarter circular structure.

[0098] In a second aspect, an embodiment of the present application provides a battery comprising the above-mentioned battery cell.

[0099] In a third aspect, an embodiment of the present application provides an electrical device comprising the above-mentioned battery.

[0100] It can be understood that the beneficial effects of the second and third aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here.

[0101] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A battery cell, characterized in that: include: An electrode assembly, the electrode assembly comprising an electrode body and an electrode ear provided at an end of the electrode body; A current collecting component is placed on the electrode tab, and an outer edge of the current collecting component overlaps with an outer edge of the electrode tab, so that a portion of the electrode tab is exposed to the outside.

2. The battery cell according to claim 1, characterized in that: At least part of the outer edge of the current collecting component is recessed inward to form a notch structure.

3. The battery cell according to claim 2, characterized in that: The current collecting component includes a base body, the outer edge of the base body is recessed inward to form the notch structure, and the tab can pass through the notch structure to the outside.

4. The battery cell according to claim 2, characterized in that: The current collecting component includes a base body and a stacked body which are stacked together. The base body is placed on the tab. The outer edge of the base body and / or the outer edge of the stacked body are recessed inward to form the notch structure.

5. The battery cell according to claim 4, characterized in that: The outer contour of the substrate is the same as that of the tab, and the substrate covers the tab. The outer edge of the stack is recessed inward to form the notch structure.

6. The battery cell according to any one of claims 2 to 5, characterized in that: The geometric center of the current collecting component is colinear with the winding center axis of the electrode body, and the notch structure is recessed inwardly to the geometric center of the current collecting component.

7. The battery cell according to any one of claims 1 to 5, characterized in that: A projection of one of the outer edge portions of the current collecting member on an end portion of the electrode body is close to a winding center axis of the electrode body.

8. The battery cell according to claim 7, characterized in that: A projection of an outer edge portion of the current collecting member on the electrode tab coincides with a winding center axis of the electrode body.

9. A battery, characterized in that: The invention comprises a battery cell as claimed in any one of claims 1 to 8.

10. An electrical equipment, characterized in that: Comprising the battery as claimed in claim 9.

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