Battery cell, battery, electric device, and welding apparatus

Abstract

The application discloses a battery monomer, a battery, a power utilization device and a welding device. The battery monomer comprises a shell, an electrode unit and an electrode lead-out piece. The electrode unit is accommodated in the shell and comprises at least one electrode assembly, and one electrode assembly comprises a plurality of tab groups stacked, and each tab group comprises at least one tab. The electrode lead-out piece is arranged on the shell and comprises a plurality of connecting parts, each connecting part is welded to at least one tab group; the polarity of the plurality of tab groups welded to the plurality of connecting parts of the electrode lead-out piece is the same. By arranging the plurality of connecting parts on the electrode lead-out piece, the number of layers of the tabs welded to a single connecting part is reduced, the difficulty of welding the connecting part and the tab is reduced, the connection strength between the connecting part and the corresponding tab is improved, the welding power is reduced and the welding time is shortened, the risk of tab cracking and the risk of virtual welding are reduced, and the overcurrent capacity and safety performance of the battery monomer are improved.

Description

[0001] This application is a divisional application based on application number 202211148623.4, filed on September 21, 2022, by Jiangsu Times New Energy Technology Co., Ltd. and CATL, entitled "Battery cell, battery, electrical device and welding equipment". Technical Field

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

[0003] Battery cells are widely used in electronic devices such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools, etc.

[0004] Improving the overcurrent capacity of individual battery cells is an important research direction in battery technology. Summary of the Invention

[0005] This application provides a battery cell, a battery, an electrical device, and welding equipment, which can improve the overcurrent capacity of the battery cell.

[0006] In a first aspect, this application provides a battery cell comprising a housing, an electrode unit, and an electrode lead. The electrode unit is housed within the housing and includes at least one electrode assembly. Each electrode assembly includes multiple stacked tab groups, each tab group including at least one tab. The electrode lead is disposed on the housing and includes multiple connecting portions, each connecting portion being welded to at least one tab group; the multiple tab groups welded to the multiple connecting portions of the electrode lead have the same polarity.

[0007] By setting multiple connecting parts on the electrode leads, the number of tabs welded to a single connecting part is reduced, thereby reducing the difficulty of welding the connecting part to the tab, increasing the connection strength between the connecting part and the corresponding tab, reducing welding power and shortening welding time, reducing the risk of tab cracking and poor welding, and improving the overcurrent capacity and safety performance of the battery cell.

[0008] In some embodiments, the number of tab assemblies is the same as the number of connectors, and each connector is welded to a tab assembly.

[0009] The one-to-one correspondence between multiple electrode lugs and multiple connecting parts allows for orderly stacking of the connecting parts and electrode lugs, reducing the difficulty of grouping the electrode lugs and improving welding efficiency.

[0010] In some embodiments, the plurality of connecting portions include a first connecting portion and a second connecting portion, and the plurality of tab groups of an electrode assembly include a first tab group and a second tab group. At least a portion of the first tab group is located between the first connecting portion and the second connecting portion and is welded to the first connecting portion, and at least a portion of the second tab group is located between the first tab group and the second connecting portion and is welded to the second connecting portion.

[0011] The first connecting portion and the second connecting portion can protect at least a portion of the first electrode group and at least a portion of the second electrode group from both sides, thereby reducing the risk of electrode damage.

[0012] In some embodiments, the plurality of connecting portions include a first connecting portion and a second connecting portion, and the plurality of electrode assemblies include a first electrode assembly and a second electrode assembly. At least a portion of the first electrode assembly is located on the side of the first connecting portion opposite to the second connecting portion and is welded to the first connecting portion, and at least a portion of the second electrode assembly is located on the side of the second connecting portion opposite to the first connecting portion and is welded to the second connecting portion.

[0013] In some embodiments, each connection portion is welded to a corresponding tab assembly to form a welded portion. The battery cell also includes an isolation assembly for isolating adjacent welded portions.

[0014] Isolation components can isolate adjacent welds to reduce the risk of friction between welds, reduce metal particles, reduce the risk of short circuits, and improve safety.

[0015] In some embodiments, the isolation component includes multiple isolation layers. Multiple connectors are stacked; in the stacking direction of the multiple connectors, a weld includes two weld surfaces disposed opposite each other; each weld surface is attached with an isolation layer.

[0016] An insulating layer is attached to the welding surface to cover at least part of the metal particles on the welding surface, thereby reducing the risk of metal particles falling into the electrode unit and improving safety.

[0017] In some embodiments, the isolation layer completely covers the welding surface to enclose metal particles between the welding surface and the isolation layer, reducing the risk of metal particles falling into the electrode unit and improving safety.

[0018] In some embodiments, the isolation component includes isolation layers. Two isolation layers are provided between two adjacent welded portions, and the two isolation layers are respectively attached to the two welded portions.

[0019] The two isolation layers can not only fix the residual metal particles on the two welded parts, but also form a double-layer protective structure between the two welded parts, reducing the risk of friction between the two welded parts.

[0020] In some embodiments, the isolation component includes an isolation layer. An isolation layer is provided between two adjacent welded portions, and the two surfaces of the isolation layer are respectively attached to the two welded portions.

[0021] The insulating layer not only secures residual metal particles on the two welded joints but also connects them, reducing relative displacement and the risk of friction. The insulating layer integrates multiple tab assemblies and connecting parts, thereby increasing the overall strength of the tab assemblies and reducing the risk of tab breakage.

[0022] In some embodiments, the thermal conductivity of the tab is less than 50 W / (m·℃).

[0023] The lower thermal conductivity of the tabs slows down the rate at which heat generated by the tabs dissipates outward, allowing the battery cells to exert more capacity in low-temperature environments.

[0024] In some embodiments, the melting point of the tab is greater than or equal to 1000°C.

[0025] Limiting the melting point of the tabs to 1000°C or higher can reduce the risk of tab meltdown, improve overcurrent capacity, extend the cycle life of individual battery cells, and reduce safety risks.

[0026] In some embodiments, the hardness of the tab is greater than 80 HV.

[0027] Limiting the hardness of the tabs to greater than 80 HV can effectively reduce the risk of the tabs being damaged by impurities, reduce the possibility of tab breakage, extend the cycle life of the battery cells, and reduce safety risks.

[0028] In some embodiments, the tensile strength of the tab is greater than 500 MPa.

[0029] The tensile strength of the tabs is limited to greater than 500 MPa to reduce the risk of the tabs breaking when the battery cell vibrates, extend the cycle life of the battery cell, and reduce safety risks.

[0030] In some embodiments, the tabs are copper foil, aluminum foil, steel foil, titanium foil, nickel foil, or nickel-iron alloy foil.

[0031] Copper foil, aluminum foil, steel foil, titanium foil, nickel foil, and nickel-iron alloy foil have high strength and hardness. The tabs made from these materials are not easy to break, thereby improving the current carrying capacity of the battery cell, extending the cycle life of the battery cell, and reducing safety risks.

[0032] In some embodiments, the electrode lead-out component further includes a current collector connected to multiple connection points. The current collector can collect the current from the multiple connection points to one, facilitating current extraction.

[0033] In some embodiments, the manifold and multiple connecting parts are integrally formed.

[0034] One-piece molding can reduce the resistance at the connection between the current collector and the connector, reduce heat generation, and improve the current carrying capacity of the electrode leads.

[0035] In some embodiments, the manifold passes through the housing.

[0036] The current collector passes through the housing and extends outside the housing to facilitate electrical connection with the external circuit and enable the charging and discharging of the electrode unit.

[0037] In some embodiments, the electrode lead-out member further includes electrode terminals disposed in the housing, with the electrode terminals protruding to the outside of the housing. A current collector is connected to the electrode terminals.

[0038] The electrode terminals are exposed outside the housing to facilitate connection with components outside the housing, thereby electrically connecting the electrode unit to an external circuit through the current collector and connection part to realize the charging and discharging of the electrode unit.

[0039] In some embodiments, the electrode unit includes multiple electrode assemblies, and each electrode assembly includes multiple tabs. Providing multiple electrode assemblies within a single battery cell can increase the capacity of the single battery cell.

[0040] Secondly, embodiments of this application provide a battery comprising multiple battery cells provided in any of the embodiments of the first aspect.

[0041] Thirdly, embodiments of this application provide an electrical device including a battery cell provided in any of the embodiments of the first aspect. The battery cell is used to provide electrical energy.

[0042] Fourthly, embodiments of this application provide a welding apparatus for welding multiple tab groups of an electrode assembly to multiple connecting portions of an electrode lead, wherein the polarity of the multiple tab groups welded to the multiple connecting portions of the electrode lead is the same. The welding apparatus includes multiple welding components, each welding component being used to weld the connecting portion to at least one tab group.

[0043] By setting up multiple welding components, the number of electrode layers that need to be welded in each component can be reduced, thereby reducing the difficulty of welding the connection part to the electrode, increasing the connection strength between the connection part and the corresponding electrode, reducing welding power and shortening welding time, reducing the risk of electrode cracking and poor welding, and improving the overcurrent capacity and safety performance of the battery cell. Multiple welding components can be welded simultaneously to improve welding efficiency.

[0044] In some embodiments, each welding assembly includes a first welding component and a second welding component disposed opposite to each other. The welding apparatus also includes at least three mounting plates disposed at intervals in sequence, with any two adjacent mounting plates configured to be able to move closer or further apart relative to each other. In any two adjacent mounting plates, a first welding component is fixed to the side of one mounting plate facing the other mounting plate, and a second welding component is fixed to the side of the other mounting plate facing one mounting plate.

[0045] By setting multiple mounting plates, the relative movement of the first and second welding components of multiple welding assemblies can be realized simultaneously, thereby synchronously welding multiple connecting parts and multiple electrode assemblies, improving welding efficiency. Attached Figure Description

[0046] The features, advantages, and technical effects of exemplary embodiments of this application will now be described with reference to the accompanying drawings.

[0047] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments;

[0048] Figure 2 Explosion diagrams of batteries provided for some embodiments of this application;

[0049] Figure 3 for Figure 2 The diagram shows the structure of the battery module.

[0050] Figure 4 A three-dimensional structural schematic diagram of a battery cell provided in some embodiments of this application;

[0051] Figure 5 A cross-sectional schematic diagram of a battery cell provided in some embodiments of this application;

[0052] Figure 6 for Figure 5 Enlarged view of point A in the circle;

[0053] Figure 7 A schematic diagram of the electrode unit and electrode lead-out of a battery cell provided in some embodiments of this application;

[0054] Figure 8 This is a schematic diagram of the structure of the electrode lead-out component of a battery cell provided in some embodiments of this application;

[0055] Figure 9 This is a schematic diagram of the structure of a battery cell provided in some other embodiments of this application, wherein the outer casing is omitted;

[0056] Figure 10 This is a schematic diagram of the structure of a battery cell provided in some other embodiments of this application, wherein the outer casing is omitted;

[0057] Figure 11 This is a schematic diagram of the structure of a battery cell provided in some other embodiments of this application, wherein the outer casing is omitted;

[0058] Figure 12 Explosion-proof diagrams of individual battery cells provided in other embodiments of this application;

[0059] Figure 13 for Figure 12 Enlarged view of point B in the circle;

[0060] Figure 14 This is a schematic diagram of the structure of a welding device provided in some embodiments of this application.

[0061] The accompanying drawings are not necessarily drawn to scale. Detailed Implementation

[0062] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0063] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0064] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0065] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0066] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0067] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0068] In this application, "multiple" means two or more (including two).

[0069] In this application, the term "parallel" includes not only the case of absolute parallelism, but also the case of approximate parallelism as commonly understood in engineering; similarly, "perpendicular" includes not only the case of absolute perpendicularity, but also the case of approximate perpendicularity as commonly understood in engineering.

[0070] In this application, the battery cell may include a lithium-ion secondary battery cell, a lithium-ion primary battery cell, a lithium-sulfur battery cell, a sodium-lithium-ion battery cell, a sodium-ion battery cell, or a magnesium-ion battery cell, etc., and the embodiments of this application are not limited thereto. The battery cell may be cylindrical, flat, cuboid, or other shapes, etc., and the embodiments of this application are not limited thereto.

[0071] The battery mentioned in the embodiments of this application refers to a single physical module comprising one or more battery cells to provide higher voltage and capacity. A battery may also generally include a housing for encapsulating one or more battery cells. The housing prevents liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0072] A single battery cell includes electrode components and an electrolyte. The electrode components include a positive electrode, a negative electrode, and a separator. The battery cell primarily functions by the movement of metal ions between the positive and negative electrodes. The positive electrode includes a positive current collector and a positive active material layer, which is coated on the surface of the positive current collector. The positive current collector includes a positive current collection section and a positive electrode tab connected to it. The positive current collection section is coated with the positive active material layer, while the positive electrode tab is not. Taking a lithium-ion battery as an example, the material of the positive current collector can be aluminum, and the positive active material layer includes the positive active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode includes a negative current collector and a negative active material layer, the negative active material layer being coated on the surface of the negative current collector. The negative current collector includes a negative current collection section and a negative electrode tab connected to the negative current collection section. The negative current collection section is coated with the negative active material layer, while the negative electrode tab is not coated with the negative active material layer. The material of the negative current collector can be copper, and the negative active material layer includes a negative active material, which can be carbon or silicon, etc. To ensure that a large current can pass through without melting, there are multiple positive electrode tabs stacked together, and there are multiple negative electrode tabs stacked together. The material of the separator can be PP (polypropylene) or PE (polyethylene), etc. Furthermore, the electrode assembly can be a wound structure or a stacked structure, and the embodiments of this application are not limited to these.

[0073] Battery cells typically have electrode leads for electrical connection to electrode assemblies. Electrode assemblies can then be electrically connected to external circuits via these leads to enable charging and discharging. In related technologies, to reduce resistance and improve connection strength, the tabs of the electrode assemblies are usually connected to the electrode leads by welding.

[0074] To improve the current-carrying capacity of individual battery cells and reduce heat generation from the tabs, the inventors attempted to increase the number of tab layers. However, they discovered that as the number of tab layers increases, the welding power and welding holding time also increase accordingly. Increasing the welding power and holding time makes the tabs prone to cracking, resulting in insufficient current-carrying capacity of the battery cell. When the battery cell vibrates, the cracked tabs may break off and become embedded inside the electrode assembly, causing a short circuit and posing a safety risk. Conversely, without increasing the welding power and holding time, the large number of tab layers may lead to incomplete soldering, resulting in insufficient connection strength between the tabs and electrode leads. When the battery cell vibrates, the tabs may detach from the electrode assembly and become embedded inside, causing a short circuit and posing a safety risk.

[0075] In view of this, this application provides a technical solution in which a battery cell includes a casing, an electrode unit, and an electrode lead-out member. The electrode unit is housed within the casing and includes multiple stacked tab groups, each tab group including at least one tab. The electrode lead-out member is disposed on the casing and includes multiple connecting portions, each connecting portion being welded to at least one tab group.

[0076] By setting multiple connecting parts on the electrode leads, the number of tabs welded to a single connecting part is reduced, thereby reducing the difficulty of welding the connecting part to the tab, increasing the connection strength between the connecting part and the corresponding tab, reducing welding power and shortening welding time, reducing the risk of tab cracking and poor welding, and improving the overcurrent capacity and safety performance of the battery cell.

[0077] The electrode plates described in the embodiments of this application are applicable to battery cells, batteries, and electrical devices that use batteries.

[0078] Electrical devices can include vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, and power tools, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles; new energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose any special limitations on the above-mentioned electrical devices.

[0079] For ease of explanation, the following embodiments will use a vehicle as an example of an electrical device.

[0080] Figure 1 The diagram shows the structural features of a vehicle provided in some embodiments of this application.

[0081] like Figure 1 As shown, a battery 2 is installed inside the vehicle 1. The battery 2 can be located at the bottom, front, or rear of the vehicle 1. The battery 2 can be used to power the vehicle 1; for example, the battery 2 can serve as the operating power source for the vehicle 1.

[0082] Vehicle 1 may also include controller 3 and motor 4. Controller 3 is used to control battery 2 to supply power to motor 4, for example, for the power needs of vehicle 1 during start-up, navigation and driving.

[0083] In some embodiments of this application, the battery 2 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0084] Figure 2 This is an exploded schematic diagram of a battery provided for some embodiments of this application.

[0085] like Figure 2 As shown, battery 2 includes a housing 5 and battery cells ( Figure 2 (Not shown), the battery cells are housed inside the casing 5.

[0086] The housing 5 is used to house individual battery cells, and the housing 5 can have various structures. In some embodiments, the housing 5 may include a first housing portion 5a and a second housing portion 5b, which overlap each other, and together define a housing space 5c for housing the individual battery cells. The second housing portion 5b may be a hollow structure with one end open, and the first housing portion 5a may be a plate-like structure, with the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c; alternatively, both the first housing portion 5a and the second housing portion 5b may be hollow structures with one side open, with the open side of the first housing portion 5a covering the open side of the second housing portion 5b to form a housing 5 with the housing space 5c. Of course, the first housing portion 5a and the second housing portion 5b can have various shapes, such as cylinders, cuboids, etc.

[0087] To improve the sealing performance after the first housing part 5a and the second housing part 5b are connected, a sealing element, such as sealant or sealing ring, can also be provided between the first housing part 5a and the second housing part 5b.

[0088] Assuming that the first box section 5a covers the top of the second box section 5b, the first box section 5a can also be called the upper box cover, and the second box section 5b can also be called the lower box.

[0089] In battery 2, there can be one or more individual battery cells. If there are multiple individual battery cells, they can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple individual battery cells are connected in both series and parallel configurations. Multiple individual battery cells can be directly connected in series, parallel, or in a mixed configuration and then housed within housing 5. Alternatively, multiple individual battery cells can first be connected in series, parallel, or in a mixed configuration to form battery module 6, and then multiple battery modules 6 can be connected in series, parallel, or in a mixed configuration to form a whole and housed within housing 5.

[0090] Figure 3 for Figure 2 The diagram shows the structure of the battery module.

[0091] like Figure 3 As shown, in some embodiments, there are multiple battery cells 7, which are first connected in series, parallel, or mixed to form a battery module 6. The multiple battery modules 6 are then connected in series, parallel, or mixed to form a whole and housed in a casing.

[0092] Multiple battery cells 7 in battery module 6 can be electrically connected through a busbar component to achieve parallel, series, or mixed connection of multiple battery cells 7 in battery module 6.

[0093] The battery cell 7 can be a cylindrical battery cell, a square battery cell, or a battery cell of other shapes.

[0094] The battery cell 7 can be a hard-shell battery cell or a soft-pack battery cell.

[0095] Figure 4 A three-dimensional structural schematic diagram of a battery cell provided in some embodiments of this application; Figure 5 A cross-sectional schematic diagram of a battery cell provided in some embodiments of this application; Figure 6 for Figure 5 Enlarged view of point A in the circle; Figure 7 A schematic diagram of the electrode unit and electrode lead-out of a battery cell provided in some embodiments of this application; Figure 8 This is a schematic diagram of the structure of the electrode lead-out of a battery cell provided in some embodiments of this application.

[0096] like Figures 4 to 8 As shown, some embodiments of this application provide a battery cell 7 including a housing 20, an electrode unit 10, and an electrode lead-out member 30. The electrode unit 10 is housed within the housing 20 and includes a plurality of stacked tab groups 11, each tab group 11 including at least one tab 111. The electrode lead-out member 30 is disposed on the housing 20 and includes a plurality of connecting portions 31, each connecting portion 31 being welded to at least one tab group 11.

[0097] The outer shell 20 is a hollow structure, with an internal cavity for accommodating the electrode unit 10 and the electrolyte. The shape of the outer shell 20 can be determined according to the specific shape of the electrode unit 10. For example, if the electrode unit 10 is a cylindrical structure, a cylindrical outer shell can be used; if the electrode unit 10 is a cuboid structure, a cuboid outer shell can be used.

[0098] The outer casing 20 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, or other materials. This application embodiment does not impose any special limitations on this. For example, the outer casing 20 can be made of aluminum-plastic packaging film or steel-plastic packaging film.

[0099] Electrode unit 10 includes one or more electrode assemblies 10a.

[0100] Electrode assembly 10a includes a positive electrode and a negative electrode. Exemplarily, electrode assembly 10a generates electrical energy through oxidation and reduction reactions during the insertion / extraction of ions in the positive and negative electrode plates. Optionally, electrode assembly 10a further includes a separator for insulating the positive and negative electrode plates.

[0101] In some examples, the positive electrode, negative electrode, and separator are all strip structures, wound together around a central axis to form a wound structure. The wound structure can be cylindrical, flat, or other shapes. In other examples, the electrode assembly 10a can also be a stacked structure formed by arranging the positive electrode, separator, and negative electrode in layers.

[0102] The positive electrode may include one or more positive electrode tabs. Exemplarily, a positive electrode tab is a portion of the positive electrode that is not coated with an active material layer. The negative electrode may include one or more negative electrode tabs. Exemplarily, a negative electrode tab is a portion of the negative electrode that is not coated with an active material layer.

[0103] The electrode assembly 10a includes multiple stacked positive electrode tabs and multiple stacked negative electrode tabs.

[0104] In some examples, electrode unit 10 includes an electrode assembly 10a. All positive tabs of electrode assembly 10a are divided into at least two positive tab groups 11, each positive tab group 11 including at least one positive tab; all negative tabs of electrode assembly 10a are divided into at least two negative tab groups 11, each negative tab group 11 including at least one negative tab.

[0105] In other examples, the electrode unit 10 includes a plurality of electrode components 10a. The positive electrode tabs of all electrode components 10a are divided into at least two positive electrode tab groups 11, each positive electrode tab group 11 including at least one positive electrode tab; the negative electrode tabs of all electrode components 10a are divided into at least two negative electrode tab groups, each negative electrode tab group 11 including at least one negative electrode tab.

[0106] The battery cell 7 is provided with at least one electrode lead 30. The electrode lead 30 is used to connect to the tab 111 of the same polarity.

[0107] In some examples, there is one electrode lead 30. The connection portion 31 of the electrode lead 30 is used for welding to the positive electrode tab assembly 11, or the connection portion 31 of the electrode lead 30 is used for welding to the negative electrode tab assembly 11.

[0108] In some other examples, there are two electrode leads 30. The connection portion 31 of one electrode lead 30 is used for welding to the positive electrode tab group 11, and the connection portion 31 of the other electrode lead 30 is used for welding to the negative electrode tab group 11.

[0109] The tab group 11 may include one tab 111 or multiple tabs 111 stacked together. For any two adjacent tab groups 11, the number of tabs 111 in the two tab groups 11 may be the same or different.

[0110] A connecting part 31 may be welded to only one tab group 11 or to multiple tab groups 11 at the same time.

[0111] In this embodiment of the application, by providing multiple connecting portions 31 on the electrode lead-out member 30, the number of layers of the tab 111 welded to a single connecting portion 31 is reduced, thereby reducing the difficulty of welding the connecting portion 31 to the tab 111, increasing the connection strength between the connecting portion 31 and the corresponding tab 111, reducing welding power and shortening welding time, reducing the risk of tab 111 cracking and the risk of poor welding, and improving the overcurrent capacity and safety performance of the battery cell 7.

[0112] The welding processes of the multiple connecting parts 31 are independent of each other; that is, the welding process of one connecting part 31 to its corresponding tab assembly 11 is not affected by other connecting parts 31 and other tab assemblies 11. The multiple connecting parts 31 are not connected by welding.

[0113] In some embodiments, the connecting part 31 and the tab assembly 11 are connected by ultrasonic welding or laser welding.

[0114] In some embodiments, each tab group 11 includes at least two tabs 111. This embodiment can reduce the total number of tab groups 11 and the total number of connecting parts 31, thereby reducing the number of welding operations and improving welding efficiency.

[0115] In some embodiments, the number of electrodes 111 in the electrode group 11 is 2-20. Optionally, the number of electrodes 111 in the electrode group 11 is 4-10.

[0116] In some embodiments, the number of electrodes 111 in the plurality of electrode groups 11 is the same.

[0117] In some embodiments, the number of tab assemblies 11 is the same as the number of connecting portions 31, and each connecting portion 31 is welded to one tab assembly 11.

[0118] In this embodiment, multiple electrode groups 11 and multiple connecting parts 31 are arranged in a one-to-one correspondence, which can make the stacking of connecting parts 31 and electrode groups 11 orderly, reduce the difficulty of grouping electrode 111, and improve welding efficiency.

[0119] In some embodiments, the thermal conductivity of tab 111 is less than 50 W / (m·℃). The low thermal conductivity of tab 111 slows down the rate at which heat generated by tab 111 dissipates outward, allowing the battery cell to exert more capacity in low-temperature environments.

[0120] In some embodiments, the melting point of tab 111 is greater than or equal to 1000°C. Optionally, the melting point of tab 111 is 1000°C-1500°C.

[0121] When current passes through tab 111, tab 111 generates heat and rises in temperature. If the melting point of tab 111 is too low, tab 111 may melt and break during charging and discharging, causing tab 111 to fail and causing safety problems.

[0122] After in-depth research and a large number of experiments, the inventors discovered that limiting the melting point of tab 111 to greater than or equal to 1000°C can reduce the risk of tab 111 melting, improve overcurrent capacity, extend the cycle life of battery cell 7, and reduce safety risks.

[0123] In some embodiments, the hardness of tab 111 is greater than 80 HV (Vickers hardness).

[0124] During the production of the battery cell 7, the electrode assembly 10a needs to go through multiple processes; impurities generated during the production process (such as particles generated during welding) may remain on the tab 111. If the hardness of the tab 111 is insufficient, the tab 111 may develop defects such as indentations and micropores under the pressure of impurities; when the battery cell 7 vibrates, the defects on the tab 111 may worsen under tension, leading to the risk of the tab 111 breaking.

[0125] After in-depth research and a large number of experiments, the inventors discovered that limiting the hardness of the tab 111 to greater than 80HV can effectively reduce the risk of the tab 111 being damaged by impurities, reduce the possibility of the tab 111 breaking, extend the cycle life of the battery cell 7, and reduce safety risks.

[0126] In some embodiments, the tensile strength of the tab 111 is greater than 500 MPa.

[0127] Tensile strength, also known as tensile resistance, characterizes a material's resistance to maximum uniform plastic deformation. Before being subjected to maximum tensile stress, a tensile specimen exhibits uniform deformation; however, beyond this stress, the material begins to neck, resulting in concentrated deformation. For brittle materials with little or no uniform plastic deformation, it reflects the material's fracture resistance. For metallic materials, tensile strength is the critical value for the transition from uniform plastic deformation to localized concentrated plastic deformation, and it is also the maximum load-bearing capacity of a metal under static tensile conditions.

[0128] When the battery cell 7 is vibrated due to an external impact, the electrode assembly 10a may move within the housing 20, causing the tab 111 to be under tension. If the tensile strength of the tab 111 is insufficient, there is a risk that the tab 111 may break.

[0129] After in-depth research and a large number of experiments, the inventors discovered that limiting the tensile strength of the tab 111 to greater than 500 MPa can reduce the risk of the tab 111 being pulled off when the battery cell 7 vibrates, extend the cycle life of the battery cell 7, and reduce safety risks.

[0130] The tab 111 in this embodiment has high strength and high hardness, which can effectively reduce wrinkling and collapse of the tab 111 and reduce the risk of breakage.

[0131] In some embodiments, the tab 111 is made of copper foil, aluminum foil, steel foil, titanium foil, nickel foil, or nickel-iron alloy foil. Copper foil, aluminum foil, steel foil, titanium foil, nickel foil, and nickel-iron alloy foil have high strength and hardness, and the tab 111 made of these materials is not easy to break, thereby improving the overcurrent capacity of the battery cell 7, extending the cycle life of the battery cell 7, and reducing safety risks.

[0132] Optionally, the tab 111 is made of stainless steel foil.

[0133] In some embodiments, the tab 111 may also be a specially treated high-strength copper foil or high-strength aluminum foil.

[0134] In some embodiments, the connecting portion 31 and the electrode tab 111 may be made of the same material or different materials. Optionally, the connecting portion 31 and the electrode tab 111 may be made of the same material to reduce welding difficulty and increase welding strength.

[0135] In some embodiments, the electrode lead-out member 30 further includes a current collector 32, which is connected to a plurality of connection portions 31.

[0136] The current collector 32 and the connecting part 31 can be an integrally formed structure or two independently formed parts. In some examples, the current collector 32 and the connecting part 31 are integrally formed; in other examples, multiple connecting parts 31 are connected to the current collector 32 by welding, bonding, snap-fitting or other means through holes; in still other examples, a portion of the connecting parts 31 and the current collector 32 are integrally formed, and the remaining portion of the connecting parts 31 is connected to the current collector 32 by welding, bonding, snap-fitting or other means through holes.

[0137] The current collector 32 can collect the current from multiple connection parts 31 into one, which facilitates the extraction of current.

[0138] In some embodiments, the current collector 32 and the plurality of connecting portions 31 are integrally formed. Integral forming can reduce the resistance at the connection between the current collector 32 and the connecting portions 31, reduce heat generation, and improve the current carrying capacity of the electrode lead-out member 30.

[0139] In some embodiments, a plurality of connecting portions 31 are connected to the same end of the current collector 32. Before welding the tab assembly 11 and the connecting portions 31, the plurality of connecting portions 31 may be bent relative to the current collector 32 and form a forked structure to create a gap between adjacent connecting portions 31. Welding equipment may extend into the gap to weld the connecting portions 31 and the corresponding tab assembly 11.

[0140] After welding is completed, multiple connecting parts 31 and multiple electrode lugs 11 can be gathered towards the center to reduce the space occupied by the multiple connecting parts 31 and multiple electrode lugs 11 and improve space utilization.

[0141] In some embodiments, the current collector 32 passes through the housing 20. One end of the current collector 32 is housed within the housing 20 and connected to a plurality of connecting portions 31, while the other end of the current collector 32 is located outside the housing 20.

[0142] The current collector 32 passes through the housing 20 and extends outside the housing 20 to facilitate electrical connection with the external circuit and realize the charging and discharging of the electrode unit 10.

[0143] For example, the current collector 32 is used to be electrically connected to the current collector component to realize series or parallel connection between battery cells 7.

[0144] In some embodiments, each connection portion 31 is welded to a corresponding tab assembly 11 to form a weld portion 40. The battery cell 7 also includes an isolation assembly 50 for isolating adjacent weld portions 40.

[0145] For example, during welding, a portion of the connecting portion 31 and a portion of each tab 111 of the tab assembly 11 melts and forms a molten pool, which solidifies to form a weld portion 40. The weld portion 40 fixes the connecting portion 31 and the corresponding tab assembly 11 together.

[0146] The isolation component 50 can isolate part of the welded portion 40 or isolate all of the welded portion 40. Optionally, the isolation component 50 can isolate any two adjacent welded portions 40.

[0147] The surface of the welded part 40 is uneven. If two welded parts 40 come into contact with each other, when the battery cell 7 vibrates, the two welded parts 40 may rub against each other and form metal particles. If the metal particles fall into the electrode unit 10, they may cause a short circuit.

[0148] The isolation component 50 of this application embodiment can isolate adjacent welded parts 40 to reduce the risk of friction between welded parts 40, reduce metal particles, reduce the risk of short circuit, and improve safety.

[0149] In some embodiments, the isolation component 50 includes a plurality of isolation layers 51. A plurality of connecting portions 31 are stacked. In the stacking direction of the plurality of connecting portions 31, a welding portion 40 includes two welding surfaces 41 disposed opposite to each other. Each welding surface 41 is attached to an isolation layer 51.

[0150] Attachment can refer to attaching and connecting.

[0151] The isolation layer 51 may completely cover the welding surface 41, or it may only cover a portion of the welding surface 41.

[0152] After welding, metal particles may remain on the weld surface 41. When the battery cell 7 vibrates, these metal particles may fall into the electrode unit 10, potentially causing a short circuit.

[0153] In this embodiment, the isolation layer 51 is attached to the welding surface 41 to cover at least a portion of the metal particles on the welding surface 41, thereby reducing the risk of metal particles falling into the electrode unit 10 and improving safety.

[0154] In some embodiments, the isolation layer 51 is bonded to the welding surface 41.

[0155] In some embodiments, the insulating layer 51 is bonded to an unwelded area (which may be an unwelded area of ​​the connecting portion 31 or an unwelded area of ​​the tab assembly 11). The unwelded area is relatively flat, and bonding the insulating layer 51 to the unwelded area can improve the stability of the insulating layer 51 and reduce the risk of the insulating layer 51 falling off.

[0156] In some embodiments, the isolation layer 51 completely covers the welding surface 41 to enclose the metal particles between the welding surface 41 and the isolation layer 51, reducing the risk of metal particles falling into the electrode unit 10 and improving safety.

[0157] In some embodiments, the isolation component 50 includes an isolation layer 51. Two isolation layers 51 are provided between two adjacent welded portions 40, and the two isolation layers 51 are respectively attached to the two welded portions 40.

[0158] For example, one isolation layer 51 covers one welding surface 41 of one welding part 40, and another isolation layer 51 covers one welding surface 41 of another welding part 40.

[0159] The two isolation layers 51 can not only fix the residual metal particles on the two welded parts 40, but also form a double-layer protective structure between the two welded parts 40, reducing the risk of friction between the two welded parts 40.

[0160] In some embodiments, the isolation layer 51 may be single-sided tape or double-sided tape. For example, the isolation layer 51 is double-sided tape, and the two isolation layers 51 located between the two welded portions 40 are bonded together.

[0161] In some embodiments, the plurality of connecting portions 31 include a first connecting portion 31a and a second connecting portion 31b, and the plurality of electrode assemblies 11 include a first electrode assembly 11a and a second electrode assembly 11b. At least a portion of the first electrode assembly 11a is located on the side of the first connecting portion 31a opposite to the second connecting portion 31b and is welded to the first connecting portion 31a, and at least a portion of the second electrode assembly 11b is located on the side of the second connecting portion 31b opposite to the first connecting portion 31a and is welded to the second connecting portion 31b.

[0162] In some embodiments, the first connecting portion 31a and the second connecting portion 31b are connected to the same end of the current collector 32. Before welding, the first connecting portion 31a is bent in a direction away from the second connecting portion 31b, and the second connecting portion 31b is bent in a direction away from the first connecting portion 31a, so as to form a gap between the first connecting portion 31a and the second connecting portion 31b.

[0163] The welding equipment can extend into the gap to weld the first tab assembly 11a to the first connecting portion 31a and the second tab assembly 11b to the second connecting portion 31b. After welding, the first connecting portion 31a and the second connecting portion 31b move closer to each other to bring the first tab assembly 11a and the second tab assembly 11b together.

[0164] By stacking the first tab assembly 11a onto the side of the first connecting portion 31a opposite to the second connecting portion 31b, interference between the current collector 32 and the first tab assembly 11a can be avoided, thereby reducing the size requirements of the first connecting portion 31a. Similarly, by stacking the second tab assembly 11b onto the side of the second connecting portion 31b opposite to the first connecting portion 31a, interference between the current collector 32 and the second tab assembly 11b can be avoided, thereby reducing the size requirements of the second connecting portion 31b.

[0165] Figure 9 The diagram below shows the structure of a battery cell provided in some other embodiments of this application, where the outer casing is omitted.

[0166] like Figure 9 As shown, in some embodiments, the plurality of connecting portions 31 include a first connecting portion 31a and a second connecting portion 31b, and the plurality of electrode groups 11 include a first electrode group 11a and a second electrode group 11b. At least a portion of the first electrode group 11a is located between the first connecting portion 31a and the second connecting portion 31b and is welded to the first connecting portion 31a. At least a portion of the second electrode group 11b is located between the first electrode group 11a and the second connecting portion 31b and is welded to the second connecting portion 31b.

[0167] In the embodiments of this application, the first connecting portion 31a and the second connecting portion 31b can protect at least a portion of the first tab assembly 11a and at least a portion of the second tab assembly 11b from both sides, thereby reducing the risk of damage to the tab 111.

[0168] In some embodiments, the first connecting portion 31a and the second connecting portion 31b are connected to the same end of the current collector 32. Before welding, the first connecting portion 31a is bent in a direction away from the second connecting portion 31b, and the second connecting portion 31b is bent in a direction away from the first connecting portion 31a, so as to form a gap between the first connecting portion 31a and the second connecting portion 31b.

[0169] The first tab assembly 11a and the second tab assembly 11b can extend into the gap and are welded to the first connecting portion 31a and the second connecting portion 31b, respectively. After welding, the first connecting portion 31a and the second connecting portion 31b move closer to each other to bring the first tab assembly 11a and the second tab assembly 11b together.

[0170] Figure 10 The diagram below shows the structure of a battery cell provided in some other embodiments of this application, where the outer casing is omitted.

[0171] like Figure 10 As shown, in some embodiments, the isolation component 50 includes an isolation layer 51. An isolation layer 51 is provided between two adjacent welded portions 40, and the two surfaces of the isolation layer 51 are respectively attached to the two welded portions 40.

[0172] The isolation layer 51 can both fix the residual metal particles on the two welded parts 40 and connect the two welded parts 40 to reduce the relative displacement of the two welded parts 40 and reduce the risk of friction between the two welded parts 40. The isolation layer 51 connects the multiple tab assemblies 11 and the multiple connecting parts 31 into one, thereby improving the overall strength of the multiple tab assemblies 11 and reducing the risk of tab 111 breakage.

[0173] In some embodiments, the isolation layer 51 may be formed by coating an colloid.

[0174] Figure 11 The following is a schematic diagram of the structure of a battery cell provided in some other embodiments of this application, wherein the outer casing 20 is omitted.

[0175] like Figure 11 As shown, in some embodiments, the electrode unit includes a plurality of electrode assemblies 10a, each electrode assembly 10a including at least one tab group 11.

[0176] A tab 111 of an electrode assembly 10a may not necessarily form a tab group 11 with its other tabs 111, but may form a tab group 11 with the tabs 111 of other electrode assemblies 10a. For example, a portion of the tabs 111 of an electrode assembly 10a may form a tab group 11 with a portion of the tabs 111 of another electrode assembly 10a.

[0177] In this embodiment, multiple electrode assemblies 10a are provided within the battery cell 7, which can increase the capacity of the battery cell 7. In this embodiment, the tabs 111 of the multiple electrode assemblies 10a are connected in groups, which will not cause poor welding due to too many layers of tabs 111.

[0178] In some embodiments, the number of connection portions 31 of the electrode lead-out member 30 may also be four. Of course, the number of connection portions 31 of the electrode lead-out member 30 may also be three, five or more.

[0179] Figure 12 This is an exploded view of a battery cell provided in some other embodiments of this application. Figure 13 for Figure 12 Enlarged view of point B in the circle.

[0180] like Figure 12 and Figure 13 As shown, the electrode lead-out member 30 also includes an electrode terminal 33 disposed on the housing 20, with the electrode terminal 33 protruding to the outside of the housing 20. The current collector 32 is connected to the electrode terminal 33.

[0181] The current collector 32 can be connected to the electrode terminal 33 by bonding, welding, riveting or other means.

[0182] Electrode terminals 33 are exposed to the outside of housing 20 to facilitate connection with components outside housing 20 (e.g., busbar components), thereby electrically connecting electrode unit 10 to an external circuit via current collector 32 and connection portion 31 to realize charging and discharging of electrode unit 10.

[0183] In some embodiments, the housing 20 includes a housing 21 and an end cap 22, the housing 21 having an opening and the end cap 22 for closing the opening.

[0184] The shell 21 and the end cap 22 enclose and form a receiving cavity.

[0185] The housing 21 can have various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 21 can be determined according to the specific shape and size of the electrode unit 10. The material of the housing 21 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose any special limitations on this.

[0186] The shape of the end cap 22 can be adapted to the shape of the housing 21 to fit the housing 21. Optionally, the end cap 22 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the end cap 22 is not easily deformed when subjected to compression and impact, so that the battery cell 7 can have higher structural strength and improve safety performance. The end cap 22 is connected to the housing 21 by welding, bonding, snap-fitting or other means.

[0187] The housing 21 may have an opening on one side, and the end cap 22 may be one that covers the opening of the housing 21. Alternatively, the housing 21 may have an opening on both sides, and the end caps 22 may be two, with the two end caps 22 respectively covering the two openings of the housing 21.

[0188] In some embodiments, electrode terminals 33 are mounted on end caps 22.

[0189] In some embodiments, the battery cell 7 is a cylindrical battery cell. Exemplarily, the casing 20 of the battery cell 7 is cylindrical.

[0190] In some embodiments, the battery cell 7 is a square battery cell. Exemplarily, the casing 20 of the battery cell 7 is rectangular.

[0191] According to some embodiments of this application, this application also provides a battery comprising multiple battery cells of any of the above embodiments.

[0192] According to some embodiments of this application, this application also provides an electrical device, including a battery cell from any of the above embodiments, wherein the battery cell is used to provide electrical energy to the electrical device. The electrical device can be any of the aforementioned devices or systems that utilize battery cells.

[0193] Figure 14 This is a schematic diagram of the structure of a welding device provided in some embodiments of this application.

[0194] like Figure 14 As shown, this application embodiment provides a welding apparatus 8, which can be used to weld multiple tab assemblies 11 of an electrode unit 10 to multiple connection portions 31 of an electrode lead-out member 30. The welding apparatus 8 includes multiple welding components 81, each welding component 81 being used to weld the connection portion 31 to at least one tab assembly 11.

[0195] This embodiment of the application, by setting multiple welding components 81, can reduce the number of layers of tabs 111 that need to be welded to each welding component 81, thereby reducing the difficulty of welding the connection part 31 to the tabs 111, increasing the connection strength between the connection part 31 and the corresponding tabs 111, reducing welding power and shortening welding time, reducing the risk of tab 111 cracking and poor welding, and improving the overcurrent capacity and safety performance of the battery cell 7. The multiple welding components 81 in this embodiment of the application can be welded simultaneously to improve welding efficiency.

[0196] In some embodiments, each welding assembly 81 includes a first welding component 811 and a second welding component 812 disposed opposite to each other. The welding apparatus 8 also includes at least three mounting plates 82 disposed at intervals in sequence, with any two adjacent mounting plates 82 configured to be able to move closer or further apart. In any two adjacent mounting plates 82, the first welding component 811 is fixed to the side of one mounting plate 82 facing the other mounting plate 82, and the second welding component 812 is fixed to the side of the other mounting plate 82 facing the first mounting plate 82.

[0197] The first welding component 811 and the second welding component 812 can clamp the connecting part 31 and the corresponding electrode group 11 from both sides to weld the connecting part 31 and the corresponding electrode group 11.

[0198] In two adjacent mounting plates 82, one may be fixed and the other movable. Alternatively, both mounting plates 82 may be movable.

[0199] The two mounting plates 82 can be moved away from each other to increase the distance between the first welding component 811 and the second welding component 812; then, the connecting part 31 and the electrode assembly 11 can extend between the first welding component 811 and the second welding component 812; then, the two mounting plates 82 can be brought closer to each other, and the first welding component 811 and the second welding component 812 press and weld the connecting part 31 and the electrode assembly 11 from both sides; finally, the two mounting plates 82 can be moved away from each other, and the first welding component 811 and the second welding component 812 disengage from the connecting part 31 and the electrode assembly 11.

[0200] By setting multiple mounting plates 82, the relative movement of the first welding component 811 and the second welding component 812 of multiple welding assemblies 81 can be realized simultaneously, thereby synchronously welding multiple connecting parts 31 and multiple electrode groups 11, improving welding efficiency.

[0201] In some embodiments, the first welding component 811 is a welding head, and the second welding component 812 is a welding base.

[0202] In some embodiments, there are three mounting plates 82. Exemplarily, the middle mounting plate 82 may be fixed, while the mounting plates 82 on both sides may be movable.

[0203] Reference Figures 4 to 8 According to an embodiment of this application, the battery cell 7 includes a housing 20, an electrode assembly 10a, and an electrode lead-out member 30. The electrode assembly 10a is housed within the housing 20 and includes a first tab group 11a and a second tab group 11b stacked together. Both the first tab group 11a and the second tab group 11b include a plurality of tabs 111 stacked together.

[0204] The electrode lead-out member 30 includes a first connecting part 31a, a second connecting part 31b, and a current collector 32. The first connecting part 31a and the second connecting part 31b are connected to the end of the current collector 32 facing the electrode assembly 10a and are stacked. The end of the current collector 32 away from the electrode assembly 10a extends to the outside of the housing 20.

[0205] At least a portion of the first tab assembly 11a is located on the side of the first connecting portion 31a opposite to the second connecting portion 31b and is welded to the first connecting portion 31a. At least a portion of the second tab assembly 11b is located on the side of the second connecting portion 31b opposite to the first connecting portion 31a and is welded to the second connecting portion 31b.

[0206] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0207] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features. However, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A battery cell, characterized in that, include: shell; An electrode unit, housed within the housing and including at least one electrode assembly, wherein one electrode assembly includes a plurality of stacked tab groups, and each tab group includes at least one tab. An electrode lead-out component is disposed on the housing and includes a current collector and a plurality of connecting portions. Each of the connecting portions is welded to at least one of the tabs to form a welded portion. The polarity of the plurality of tabs welded to the plurality of connecting portions of the electrode lead-out component is the same. The current collector and the plurality of connecting portions are integrally formed. One end of the current collector is accommodated in the housing and connected to the plurality of connecting portions. The other end of the current collector is located outside the housing. as well as An isolation assembly for isolating adjacent welded portions; The plurality of connecting portions include a first connecting portion and a second connecting portion disposed adjacently, the first connecting portion and the second connecting portion being connected to the same end of the current collecting portion, the first connecting portion being bent in a direction away from the second connecting portion, the second connecting portion being bent in a direction away from the first connecting portion, and at least a portion of the isolation component being located between the first connecting portion and the second connecting portion.

2. The battery cell according to claim 1, characterized in that, The number of electrode assemblies is the same as the number of connecting parts, and each connecting part is welded to one electrode assembly.

3. The battery cell according to claim 1, characterized in that, The plurality of tab groups of one of the electrode assemblies includes a first tab group and a second tab group; At least a portion of the first electrode assembly is located between the first connecting portion and the second connecting portion and is welded to the first connecting portion; at least a portion of the second electrode assembly is located between the first electrode assembly and the second connecting portion and is welded to the second connecting portion; or, at least a portion of the first electrode assembly is located on the side of the first connecting portion opposite to the second connecting portion and is welded to the first connecting portion; at least a portion of the second electrode assembly is located on the side of the second connecting portion opposite to the first connecting portion and is welded to the second connecting portion.

4. The battery cell according to claim 1, characterized in that, The isolation component includes multiple isolation layers; The plurality of connecting portions are stacked; in the stacking direction of the plurality of connecting portions, one welding portion includes two welding surfaces disposed opposite to each other; each welding surface is attached with the isolation layer.

5. The battery cell according to claim 4, characterized in that, The isolation layer completely covers the welding surface.

6. The battery cell according to claim 1, characterized in that, The isolation component includes an isolation layer; Two isolation layers are provided between two adjacent welded parts, and the two isolation layers are respectively attached to the two welded parts.

7. The battery cell according to claim 1, characterized in that, The isolation component includes an isolation layer; An isolation layer is provided between two adjacent welded parts, and the two surfaces of the isolation layer are respectively attached to the two welded parts.

8. The battery cell according to claim 1, characterized in that, The thermal conductivity of the electrode tab is less than 50 W / (m·℃).

9. The battery cell according to claim 1, characterized in that, The melting point of the electrode is greater than or equal to 1000°C.

10. The battery cell according to claim 1, characterized in that, The hardness of the electrode tab is greater than 80HV, and the tensile strength of the electrode tab is greater than 500MPa.

11. The battery cell according to claim 1, characterized in that, The tabs are made of steel foil, copper foil, aluminum foil, titanium foil, nickel foil, or nickel-iron alloy foil.

12. The battery cell according to claim 1, characterized in that, The electrode unit includes a plurality of electrode components, and each electrode component includes a plurality of tab groups.

13. A battery, characterized in that, It includes multiple battery cells according to any one of claims 1-12.

14. An electrical appliance, characterized in that, Includes a battery cell according to any one of claims 1-12, the battery cell being used to provide electrical energy.

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