Electrode assembly, battery cell, battery and electric device

Abstract

The utility model discloses an electrode assembly, a battery monomer, a battery and a power utilization device. The battery monomer comprises an electrode assembly, and the electrode assembly comprises a first pole piece and a second pole piece. The first pole piece comprises a first body and a first pole lug, the first pole lug is provided with a first segmentation groove, the first segmentation groove segments the first pole lug into a plurality of first sub-pole lugs, and each first sub-pole lug is connected with the first body. The second pole piece and the first pole piece are stacked; the second pole piece comprises a second tab; wherein the plurality of first sub-tabs are respectively connected with the second tab. According to the structure, on one hand, the risk that the single lug is prone to burst points, bubbles and cracks in the welding process can be reduced; and on the other hand, the plurality of first sub-tabs are simultaneously connected with the second tab, so that the structural strength of connection of the first tab and the second tab can be improved, the overcurrent capacity between the first tab and the second tab can be improved, and the operation stability of the single battery is improved.

Description

Technical Field

[0001] The present application relates to the field of batteries, and in particular to an electrode assembly, a battery cell, a battery, and an electrical device. Background Art

[0002] Batteries are widely used in electronic devices, such as mobile phones, laptop computers, battery cars, electric vehicles, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, electric tools, and energy storage systems, etc.

[0003] Currently, how to improve the stability of battery cells during operation is also one of the problems studied in this field. Summary of the Utility Model

[0004] In view of the above problems, the present application provides an electrode assembly, a battery cell, a battery, and an electrical device, which can reduce the risk of battery cell operation failures caused by cracking of some tab ears in the battery cell and improve the stability of battery cell operation.

[0005] In a first aspect, the present application provides a battery cell, including an electrode assembly. The electrode assembly includes a first electrode tab and a second electrode tab. The first electrode tab includes a first body and a first tab ear. A first dividing groove is provided on the first tab ear, and the first dividing groove divides the first tab ear into a plurality of first sub-tab ears, and each first sub-tab ear is respectively connected to the first body. The second electrode tab is stacked with the first electrode tab, and the second electrode tab includes a second tab ear. Among them, the plurality of first sub-tab ears are respectively connected to the second tab ear.

[0006] In the technical solution of the embodiment of the present application, a first dividing groove is provided in the first electrode tab to divide the first tab ear into a plurality of first sub-tab ears, and a first tab ear connecting member is provided between each first sub-tab ear and the second tab ear to connect the plurality of first sub-tab ears to the second tab ear at the same time. On the one hand, it can reduce the risk of explosion points, bubbles, and cracks that are likely to occur in a single tab ear during the welding process; on the other hand, the plurality of first sub-tab ears are connected to the second tab ear at the same time, which can increase the structural strength of the connection between the first tab ear and the second tab ear, and can also increase the current-carrying capacity between the first tab ear and the second tab ear. In the case where a certain first sub-tab ear cracks, the other first sub-tab ears can still be normally electrically connected to the second tab ear, improving the operation stability of the battery cell.

[0007] In some embodiments, the number of first pole pieces is two, the second pole piece is disposed between the two first pole pieces, and any one of the second pole tabs is connected to at least two first sub-pole tabs. The outer pole tabs are subjected to greater forces during the assembly and folding process and are prone to deformation. In the above structure, the second pole piece is disposed on the inner layer, the first pole piece is disposed on the outer layer, and the first pole tab is divided into multiple first sub-pole tabs, which can effectively reduce the risk of rupture of the outer pole tab during folding due to the greater force, improve the stability of the connection between the first pole tab and the second pole tab, and further improve the operating stability of the battery cell. Moreover, the second pole tab is arranged as a single-piece structure, which can improve the energy density of the battery cell and reduce the processing difficulty of the electrode assembly.

[0008] In some embodiments, the electrode assembly further includes a third pole piece, the third pole piece includes a third body and a third pole tab, a second dividing groove is provided on the third pole tab to divide the third pole tab into multiple second sub-pole tabs, the second sub-pole tabs are electrically connected to the first sub-pole tabs, the number of the third pole pieces is multiple, and the multiple third pole pieces are stacked on a side of the first pole piece away from the second pole piece. In the above structure, setting the pole tabs of the multiple outer pole pieces as a multi-sub-pole-tab structure can further reduce the risk of cracking during the folding and assembly of the outer pole tabs and improve the yield rate of the battery cell.

[0009] In some embodiments, the orthographic projection of the second dividing groove on the first pole piece coincides with at least a part of the first dividing groove. In the above technical solution, aligning at least a part of the second dividing groove with the first dividing groove can improve the structural consistency of the outer pole tabs, improve the force balance of the multi-pole-tab structure on the outer layer, and improve the stability of the connection between the third sub-pole tab and the first sub-pole tab. In some embodiments, the thickness of the first pole tab is greater than the thickness of the second pole tab, and / or the thickness of the third pole tab is greater than the thickness of the second pole tab. In the above structure, setting the thickness of the outer pole tabs to be relatively thick can further improve the structural strength of the outer pole tabs, increase the anti-strain performance of the outer pole tabs, reduce the risk of cracking of the outer pole tabs, and improve the operating stability of the battery cell.

[0010] In some embodiments, the thickness of the first pole tab is H1, the thickness of the second pole tab is H2, and the thickness of the third pole tab is H3. H1, H2, and H3 satisfy the relationship: H2 < H1 ≤ 5H2, and / or H2 < H3 ≤ 5H2. In the above technical solution, setting the thicknesses of the outer pole tabs and the inner pole tabs within a reasonable range can reduce the risk of cracking of the outer pole tabs while minimizing the space occupied by the outer pole tabs as much as possible and improving the energy density of the battery cell.

[0011] In some embodiments, the first dividing groove is formed by extending from the edge of the first tab away from the first body towards the first body, and / or the second dividing groove is formed by extending from the edge of the third tab away from the third body towards the third body. In the above technical solution, a plurality of first dividing grooves extend from the top to the root of the first tab, dividing the first tab into a plurality of first sub-tabs arranged side by side along one side of the first body, so as to reduce the risk of cracking of the single tab edge due to excessive stress during the welding process and improve the anti-cracking performance of the third tab. A plurality of second dividing grooves extend from the top to the root of the third tab, dividing the third tab into a plurality of third sub-tabs arranged side by side along one side of the third body, so as to reduce the risk of cracking of the single tab edge due to excessive stress during the welding process and improve the anti-cracking performance of the third tab.

[0012] In some embodiments, the first body includes a conductor and an active material layer disposed on the surface of the conductor along a first direction. The first electrode sheet further includes a first connecting portion, the first connecting portion is connected to one side of the conductor along a second direction, the second direction intersects the first direction, and a plurality of first sub-tabs are respectively connected to the first connecting portion, and a first dividing groove is formed between two adjacent first sub-tabs. In the above structure, by providing the first connecting portion, the connection strength between the first sub-tab and the conductor is improved, and the risk of the first sub-tab falling off is reduced.

[0013] In some embodiments, at least two of the conductor, the first connecting portion, and the first sub-tab are integrally formed structures. The above technical solution improves the connection strength between the first body, the first connecting portion, and the first sub-tab, and improves the overall structural strength of the first electrode sheet.

[0014] In some embodiments, a plurality of sub-tabs are arranged at intervals along a third direction and are sequentially connected to the first connecting portion, and the third direction intersects the plane where the first direction and the second direction are located. In the above structure, a plurality of sub-tabs are arranged on one side of the conductor, which can effectively reduce the risk of cracking of the tab edge during the welding process and improve the structural stability of the first tab.

[0015] In a second aspect, the present application provides an electrode assembly, which includes a first electrode sheet and a second electrode sheet. The first electrode sheet includes a first body and a first tab, and a first dividing groove is provided on the first tab, and the first dividing groove divides the first tab into a plurality of first sub-tabs, and each first sub-tab is respectively connected to the first body. The second electrode sheet is stacked with the first electrode sheet, and the second electrode sheet includes a second tab. Among them, a plurality of first sub-tabs are respectively connected to the second tab.

[0016] In the above structure, a first dividing groove is provided in the first pole piece to divide the first tab into a plurality of first sub-tabs, and a first tab connecting member is provided between each first sub-tab and the second tab to connect the plurality of first sub-tabs to the second tab simultaneously. On the one hand, it can reduce the risk of explosion points, bubbles and cracks occurring in a single tab during the welding process; on the other hand, the plurality of first sub-tabs are connected to the second tab simultaneously, which can increase the structural strength of the connection between the first tab and the second tab, and can also increase the current-carrying capacity between the first tab and the second tab. In the case where a certain first sub-tab cracks, the other first sub-tabs can still be normally electrically connected to the second tab, improving the operation stability of the battery cell.

[0017] Thirdly, the present application provides a battery, which includes the battery cell in the above embodiment, or includes the electrode assembly in the above embodiment.

[0018] Fourthly, the present application provides an electrical device, which includes the battery in the above embodiment, and the battery is used to provide electrical energy.

[0019] The above description is only an overview of the technical solution of the present application. In order to be able to more clearly understand the technical means of the present application, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present application more obvious and understandable, the following specifically illustrates the specific embodiments of the present application. Description of the Drawings

[0020] Next, the features, advantages and technical effects of the exemplary embodiments of the present application will be described with reference to the drawings.

[0021] Figure 1 Schematic structural diagram of a vehicle provided in an embodiment of the present application;

[0022] Figure 2 Exploded structural diagram of a battery provided in an embodiment of the present application;

[0023] Figure 3 Exploded structural diagram of a battery cell provided in an embodiment of the present application;

[0024] Figure 4 Exploded structural diagram of an electrode assembly provided in an embodiment of the present application;

[0025] Figure 5 Schematic structural diagram of a first pole piece provided in an embodiment of the present application;

[0026] Figure 6 Exploded structural diagram of an electrode assembly provided in another embodiment of the present application;

[0027] Figure 7 Exploded structural diagram of an electrode assembly provided in another embodiment of the present application;

[0028] Figure 8 Schematic structural diagram of the first electrode tab provided for another embodiment of the present application.

[0029] Detailed description of reference numerals

[0030] 1. Vehicle; 2. Battery; X. First direction; Y. Second direction; Z. Third direction; 10. Electrode assembly; 101. First electrode tab; 102. Second electrode tab; 103. First body; 104. First tab; 105. First dividing groove; 106. First sub-tab; 107. Second tab; 108. Second body; 109. Third electrode tab; 110. Conductor; 111. Active material layer; 112. First connecting portion; 20. Housing; 25. Electrode terminal; 30. End cover; 40. Outer shell; 3. Controller; 4. Motor; 5. Box body; 51. First part; 52. Second part; 53. Accommodating space; 7. Battery cell. Detailed implementation manners

[0031] Hereinafter, embodiments of the technical solutions of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and thus are only examples and cannot be used to limit the protection scope of the present application.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above accompanying drawing descriptions are intended to cover non-exclusive inclusion.

[0033] In the description of the embodiments of the present application, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order or primary-secondary relationship of the indicated technical features. In the description of the embodiments of the present application, "a plurality of" means more than two unless otherwise specifically defined.

[0034] Referring to "embodiments" herein means that specific features, structures or characteristics described in connection with the embodiments may be included in at least one embodiment of the present application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein may be combined with other embodiments.

[0035] In the description of the embodiments of the present application, the term "and / or" is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. Additionally, in this document, the character " / " generally represents an "or" relationship between the associated objects before and after.

[0036] In the description of the embodiments of the present application, the term "plural" refers to two or more (including two). Similarly, "multiple groups" refers to two or more groups (including two groups), and "multiple pieces" refers to two or more pieces (including two pieces).

[0037] In the description of the embodiments of the present application, the orientation or positional relationship indicated by technical terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the embodiments of the present application.

[0038] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installation", "connection", "connection", "fixation", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can also be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0039] In the present application, the term "and / or" is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. Additionally, in the present application, the character " / " generally represents an "or" relationship between the associated objects before and after.

[0040] In the embodiments of the present application, the same reference numerals represent the same components. And for the sake of brevity, in different embodiments, the detailed description of the same components is omitted. It should be understood that the thickness, length, width, etc. of various components shown in the drawings of the embodiments of the present application, as well as the overall thickness, length, width, etc. of the integrated device, are only for illustrative purposes and should not constitute any limitation to the present application.

[0041] The energy density of a battery cell is a key performance indicator of the battery cell. The energy density of a battery cell refers to the amount of energy stored in the battery cell in a certain space or mass of material. The energy density can be measured in two dimensions: mass energy density and volume energy density. The energy density of a battery cell is strongly related to the internal structure of the battery cell. A high energy density often requires a stacked structure design.

[0042] Between the electrode plates of multiple single - pole tabs, usually ultrasonic welding is used to weld and connect two adjacent tabs to achieve structural connection and electrical connection. However, in the welding process of the stacked single - electrode - plate single - tab structure, problems such as explosion points, bubbles, and cracks are likely to occur. The cracking of the tab will cause the active material on the electrode plate to lose the current - passing path, making it difficult for lithium ions to be embedded and deposited, which will lead to uneven local lithium distribution and low capacity of the battery cell, etc., reducing the operating stability of the battery cell.

[0043] This is because during the welding process, the electrode plate is affected by the stress of the welding joint, resulting in explosion points, bubbles, or cracking, etc. In order to reduce the phenomenon of tab cracking, in the embodiments of the present application, a first splitting groove is provided in the first electrode plate to split the first tab into multiple first sub - tabs, and a first tab connecting member is provided between each first sub - tab and the second tab to connect the multiple first sub - tabs to the second tab simultaneously. On the one hand, it can reduce the risk of explosion points, bubbles, and cracks of a single tab during the welding process; on the other hand, the multiple first sub - tabs are connected to the second tab simultaneously, which can increase the structural strength of the connection between the first tab and the second tab, and can also increase the current - passing capacity between the first tab and the second tab. In the case where a certain first sub - tab cracks, the other first sub - tabs can still be normally electrically connected to the second tab, improving the operating stability of the battery cell.

[0044] The battery of the present application will be described in detail below.

[0045] The term "multiple" as used in the present application means two or more (including two).

[0046] In the embodiments of the present application, the battery cell can be a secondary battery, which refers to a battery cell that can activate the active material and continue to be used by charging after discharging.

[0047] The battery cell can include, but is not limited to, lithium - ion battery cells, sodium - ion battery cells, sodium - lithium - ion battery cells, lithium - metal battery cells, sodium - metal battery cells, lithium - sulfur battery cells, magnesium - ion battery cells, nickel - metal - hydride battery cells, nickel - cadmium battery cells, lead - acid battery cells, etc.

[0048] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell or a battery cell of other shapes. The prismatic battery cell includes a square shell battery cell, a blade-shaped battery cell, a multi-prismatic battery, and the multi-prismatic battery is, for example, a hexagonal prism battery, etc., and there is no special limitation in this application.

[0049] The battery mentioned in the embodiments of this application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.

[0050] In some embodiments, the battery can be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module. The multiple battery cells are stacked along the thickness direction to form a battery module.

[0051] In some embodiments, the battery can be a battery pack. The battery pack includes a box body and battery cells, and the battery cells or the battery module are accommodated in the box body.

[0052] In some embodiments, the box body can be a part of the chassis structure of a vehicle. For example, a part of the box body can become at least a part of the floor of the vehicle, or a part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0053] In some embodiments, the battery can be an energy storage device. The energy storage device includes an energy storage container, an energy storage electric cabinet, etc.

[0054] The battery disclosed in the embodiments of this application can be used in an electrical device using the battery as a power source or various energy storage systems using the battery as an energy storage element. The electrical device can be, but is not limited to, a mobile phone, a tablet computer, a laptop computer, an electric toy, an electric tool, a battery car, an electric vehicle, a ship, a spacecraft, etc.

[0055] For the convenience of description in the following embodiments, the electrical device is taken as a vehicle as an example for description.

[0056] Please refer to Figure 1 , Figure 1 which is a schematic structural diagram of a vehicle provided by an embodiment of this application. The vehicle 1 can be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 2 is arranged inside the vehicle 1, and the battery 2 can be arranged at the bottom, the head or the tail of the vehicle 1. The battery 2 can be used for power supply of the vehicle 1. For example, the battery 2 can be used as the operating power source of the vehicle 1. The vehicle 1 can also include a controller 3 and a motor 4. The controller 3 is used to control the battery 2 to supply power to the motor 4. For example, it is used for the working power requirements during the start, navigation and driving of the vehicle 1.

[0057] In some embodiments of the present application, the battery 2 can not only serve as the operating power source of the vehicle 1, but also as the driving power source of the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0058] In some embodiments, the battery can be an energy storage device. The energy storage device includes an energy storage container, an energy storage electrical cabinet, etc.

[0059] Please refer to Figure 2 , Figure 2 which is a schematic exploded view of the battery provided in an embodiment of the present application. The battery includes a box body 5 and battery cells 7, and the battery cells 7 are accommodated in the box body 8. Among them, the box body 8 is used to provide an accommodation space for the battery cells 7, and the box body 5 can adopt various structures.

[0060] In some alternative embodiments, the box body 5 includes a first part 51 and a second part 52. The first part 51 and the second part 52 cover each other, and the first part 51 and the second part 52 jointly define an accommodation space 53 for accommodating the battery cells 7.

[0061] In some embodiments, the box body 5 can be part of the chassis structure of the vehicle 1. For example, a part of the box body 5 can become at least a part of the floor of the vehicle 1, or a part of the box body 5 can become at least a part of the cross beam and longitudinal beam of the vehicle 1.

[0062] In the battery 2, there can be multiple battery cells 7. The multiple battery cells 7 can be connected in series, in parallel, or in a hybrid connection. A hybrid connection means that there are both series and parallel connections among the multiple battery cells 7. The multiple battery cells 7 can be directly connected in series, in parallel, or in a hybrid connection together, and then the whole formed by the multiple battery cells 7 is accommodated in the box body 5. Of course, the battery 2 can also be in the form that multiple battery cells 7 are first connected in series, in parallel, or in a hybrid connection to form battery modules, and then the multiple battery modules are connected in series, in parallel, or in a hybrid connection to form a whole and are accommodated in the box body 5. The battery 2 can also include other structures. For example, the battery 2 can also include a busbar component for realizing the electrical connection among the multiple battery cells 7.

[0063] Among them, each battery cell 7 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 7 can be in the shape of a cylinder, a flat body, a cuboid, or other shapes, etc.

[0064] In some embodiments, the battery cells 7 are connected through a busbar component to realize series or parallel circuits. Exemplarily, the busbar component includes a busbar, a busbar sheet, etc.

[0065] Please refer to Figure 3 , Figure 3Schematic exploded view of battery cell 7 provided by some embodiments of the present application. A battery cell 7 refers to the smallest unit that makes up battery 2. For example, Figure 3 the battery cell 7 includes a housing 40, an electrode assembly 10, and other functional components.

[0066] The housing 40 may include an end cap 30 and a housing body 20. The end cap 30 refers to a component that covers the opening of the housing body 20 to isolate the internal environment of the battery cell 7 from the external environment. Without limitation, the shape of the end cap 30 may be adapted to the shape of the housing body 20 to cooperate with the housing body 20. Optionally, the end cap 30 may be made of a material with a certain hardness and strength (such as aluminum alloy). In this way, the end cap 30 is not easily deformed when subjected to extrusion and collision, enabling the battery cell 7 to have higher structural strength and improved safety performance. Functional components such as electrode terminals 25 may be provided on the end cap 30. The electrode terminals 25 may be used for electrically connecting with the electrode assembly 10 to output or input the electrical energy of the battery cell 7.

[0067] In some embodiments, a pressure relief mechanism for relieving the internal pressure when the internal pressure or temperature of the battery cell 7 reaches a threshold may also be provided on the end cap 30. The material of the end cap 30 may also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiments of the present application do not make special restrictions on this.

[0068] The housing body 20 is a component for cooperating with the end cap 30 to form the internal environment of the battery cell 7. Among them, the formed internal environment may be used to accommodate the electrode assembly 10, the electrolyte, and other components. The housing body 20 and the end cap 30 may be independent components. An opening may be provided on the housing body 20, and the end cap 30 is covered at the opening to form the internal environment of the battery cell 7.

[0069] The electrode assembly 10 is a component in the battery cell 7 where an electrochemical reaction occurs. The housing body 20 may contain one or more electrode assemblies 10. Multiple electrode assemblies 10 form an electrode unit. The electrode assembly 10 includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of the battery cell 7, active ions (such as lithium ions) are embedded and extracted back and forth between the positive electrode and the negative electrode. The separator is disposed between the positive electrode and the negative electrode, which can play a role in preventing short circuit between the positive and negative electrodes and at the same time allow active ions to pass through. In some embodiments, the electrode assembly 10 further includes a separator, and the separator is disposed between the positive electrode and the negative electrode.

[0070] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive electrode and the negative electrode, and at the same time plays the role of transporting ions and isolating the positive and negative electrodes.

[0071] In some embodiments, the battery cell 7 further includes an electrolyte, which plays a role in conducting ions between the positive and negative electrodes. There is no specific limitation on the type of the electrolyte in this application, and it can be selected according to requirements. The electrolyte can be liquid, gel-like or solid-state.

[0072] In some embodiments, the electrode assembly 10 has a wound structure. The positive electrode sheet and the negative electrode sheet are wound into a wound structure. In some embodiments, the electrode assembly 10 has a stacked structure. In some embodiments, the shape of the electrode assembly 10 can be cylindrical, flat or multi-prismatic, etc. In some embodiments, the electrode assembly 10 is provided with tabs, and the tabs can lead the current out of the electrode assembly 10. The tabs include a positive tab and a negative tab.

[0073] Figure 4 It is a schematic structural diagram of the electrode assembly provided by an embodiment of this application. Figure 5 It is a schematic structural diagram of the first electrode sheet provided by an embodiment of this application. Figure 6 It is an exploded structural diagram of the electrode assembly provided by another embodiment of this application.

[0074] Please refer to Figures 4 to 6 , the electrode assembly 10 includes a first electrode sheet 101 and a second electrode sheet 102. The first electrode sheet 101 includes a first body 103 and a first tab 104. A first split groove 105 is provided on the first tab 104, and the first split groove 105 divides the first tab 104 into a plurality of first sub-tabs 106, and each first sub-tab 106 is respectively connected to the first body 103. The second electrode sheet 102 is stacked with the first electrode sheet 101, and the second electrode sheet 102 includes a second tab 107. Among them, the plurality of first sub-tabs 106 are respectively connected to the second tab 107.

[0075] The number of the first sub-tabs 106 can be set according to the width of the tab and the capacity of the battery cell 7, etc. Exemplarily, Figure 4 the number of the first sub-tabs 106 in the first tab 104 shown is two, and the two first sub-tabs are symmetric figures with the first split groove 105 as the axis. Figure 5 the number of the first sub-tabs 106 in the first tab 104 shown is three.

[0076] Optionally, the first tab 104 and / or the second tab 107 has a trapezoidal or rectangular structure. Optionally, the first tab 104 and / or the second tab 107 has a trapezoid with rounded corners or a rectangle with rounded corners. Among them, the trapezoidal structure can increase the connection area between the first tab 104 and the first body 103 and increase the connection strength. The rounded corner structure can reduce the risk of the sharp corner of the tab piercing the separator to cause a short circuit.

[0077] The connection of multiple first sub-tab ears 106 to the second tab ear 107 respectively means that there is not only a structural connection but also an electrical connection between the first sub-tab ears 106 and the second tab ear 107, and current can flow between the first sub-tab ears 106 and the second tab ear 107.

[0078] Optionally, the first electrode tab 101 can be an anode tab or a cathode tab. The second electrode tab 102 can be an anode tab or a cathode tab. A plurality of single-tab electrodes can also be provided on the side of the second electrode tab 102 facing away from the first electrode tab 101 to improve the energy density of the battery cell 7. The structure of the single-tab electrode can be the same as that of the second electrode tab 102, and the tab of the single-tab electrode is connected to the second electrode tab 102. An isolator can also be provided between the first electrode tab 101 and the second electrode tab 102. The second electrode tab 102 further includes a second body 108, and the second tab ear 107 is connected to the second body 108. The second body 108 is disposed opposite to the first body 103, and the first tab ear 104 is disposed opposite to the second tab ear 107. It can be understood that the structural shapes of the first electrode tab 101 and the second electrode tab 102 are basically the same. The difference is that a first dividing groove 105 is provided on the first tab ear 104 of the first electrode tab 101, and no dividing groove is provided on the second tab ear 107, and the second tab ear 107 is a single-piece single-tab structure.

[0079] Exemplarily, the first dividing groove 105 can be a strip-shaped groove penetrating in the thickness direction of the first tab ear 104, which can cut and separate between two sub-tab ears, and reduce the stress transmission between adjacent first sub-tab ears 106.

[0080] In the technical solution of the embodiment of the present application, the first electrode tab 101 can be the tab directly in contact with the welding head during the welding process. By providing the first dividing groove 105 in the first electrode tab 101, the first tab ear 104 is divided into multiple first sub-tab ears 106, which can reduce the heat and pressure concentration generated by a single tab ear during the welding process. This design helps to reduce the risk of welding defects such as explosion points, bubbles and cracks, and improve the welding quality. Multiple first sub-tab ears 106 are connected to the second tab ear 107 at the same time. Compared with the connection of a single tab ear, it has a larger contact area and more connection points. This can not only improve the firmness of the connection, but also enhance the structural strength of the entire battery cell 7, and reduce the connection failure caused by vibration or impact. Since multiple first sub-tab ears 106 participate in current transmission at the same time, the overcurrent capacity of the battery cell 7 is significantly improved. This helps to meet the requirements of high-power and high-energy-density batteries 2, and improve the use efficiency and performance of the batteries 2. When a certain first sub-tab ear 106 cracks for some reason, the other sub-tab ears can still maintain normal electrical connection with the second tab ear 107. This redundant design enables the battery cell 7 to still maintain a certain operating ability in the case of partial failure, and improves the safety and reliability of the battery 2.

[0081] like Figure 6 As shown, in some embodiments of the present application, there are two first pole pieces 101 , the second pole piece 102 is disposed between the two first pole pieces 101 , and any second pole lug 107 is connected to at least two first sub-pole lugs 106 .

[0082] During the assembly of the electrode assembly 10, the multiple stacked tabs need to be folded to reduce the space occupied by the tabs and improve the energy density of the battery cell 7. The outer tabs are subjected to greater force during the assembly and folding process and are prone to deformation.

[0083] In the above structure, by arranging the first pole piece 101 in the outer layer and dividing the first pole lug 104 into a plurality of first sub-pole lugs 106, the risk of the outer layer of the pole lug being broken due to the large force during the folding process of the pole lug can be effectively reduced. This is because the multiple sub-pole lugs share the stress and deformation originally concentrated on a single pole lug, thereby improving the mechanical stability and reliability of the entire battery cell 7. Multiple first sub-pole lugs 106 are connected to the second pole lug 107 at the same time, which not only increases the contact area, but also provides more connection points. This design can significantly improve the stability of the connection between the first pole lug 104 and the second pole lug 107, and reduce the risk of performance degradation or failure due to poor connection.

[0084] The second pole piece 102 is provided as a monolithic structure, which can simplify the processing of the electrode assembly 10 and reduce the processing difficulty and cost. At the same time, the monolithic structure also helps to improve the energy density of the battery cell 7 because it reduces unnecessary material waste and weight.

[0085] like Figure 7 As shown, in some embodiments of the present application, the electrode assembly 10 also includes a third pole piece 109, the third pole piece 109 includes a third body and a third pole ear, the third pole ear is provided with a second dividing groove to divide the third pole ear into a plurality of second sub-pole ears, the second sub-pole ears are electrically connected to the first sub-pole ear 106, the number of third pole pieces 109 is multiple, and the plurality of third pole pieces 109 are stacked on the side of the first pole piece 101 away from the second pole piece 102.

[0086] In the above structure, the tab structure of the plurality of outer pole pieces is set as a multi-sub-tab structure, which can further reduce the risk of cracking during the folding and assembly process of the outer tabs and improve the yield rate of the battery cell 7.

[0087] In some alternative embodiments, the number of the second pole pieces 102 is two, and the two second pole pieces 102 are respectively arranged corresponding to the two first pole pieces 101. A plurality of single-tab pole pieces are arranged in the second pole pieces 102. A plurality of third pole pieces 109 are arranged outside the first pole pieces 101. Wherein, the total number of layers of the inner second pole pieces 102 and the single-tab pole pieces can be 50 - 100 layers; the total number of layers of the unilateral first pole pieces 101 and the third pole pieces 109 can be 5 - 10 layers.

[0088] In some embodiments of the present application, the orthographic projection of the second dividing groove on the first pole piece 101 at least partially coincides with the first dividing groove 105.

[0089] In the above technical solution, aligning at least a part of the second dividing groove with the first dividing groove 105 can improve the structural consistency of the outer tabs, improve the force balance of the outer multi-tab structure, and improve the connection stability between the third sub-tab and the first sub-tab 106.

[0090] In some embodiments of the present application, the thickness of the first tab 104 is greater than the thickness of the second tab 107, and / or the thickness of the third tab is greater than the thickness of the second tab 107.

[0091] In the above structure, a thicker tab means a larger material cross-section, which can significantly improve the structural strength of the tab when subjected to external forces. During the assembly and operation of the battery 2, the outer tabs often need to withstand deformations such as folding and bending. The thicker tabs have stronger anti-deformation performance and are conducive to maintaining the structural integrity. The thicker tab material has better elasticity and ductility, and can withstand greater strain to a certain extent without breaking. Improve the overall durability and reliability of the battery cell 7. By increasing the thickness of the outer tabs, the risk of cracking of the outer tabs during the folding assembly process can be reduced.

[0092] Moreover, the thicker outer tabs not only improve the mechanical stability of the battery cell 7, but also enhance its electrical performance. A stable electrical connection helps to reduce energy loss and potential safety hazards during the operation of the battery cell 7, and improve the overall performance and safety of the battery 2.

[0093] In some embodiments of the present application, the thickness of the first tab 104 is H1, which is the thickness of a single first tab 104 here, or can also be the thickness of any one of the first sub-tabs 106. The thickness of the second tab 107 is H2, which is the thickness of a single second tab 107 here. The thickness of the third tab is H3, which is the thickness of a single third tab here, or can also be the thickness of any one of the third sub-tabs. H1, H2, and H3 satisfy the relationship: H2 < H1 ≤ 5H2, and / or H2 < H3 ≤ 5H2.

[0094] In the above technical solution, the thicknesses of the outer tab and the inner tab are set within a reasonable range, which can reduce the risk of cracking of the outer tab while minimizing the space occupied by the outer tab and improving the energy density of the battery cell 7.

[0095] In some embodiments of the present application, the first dividing groove 105 is formed by extending from the edge of the first tab 104 away from the first body 103 towards the first body 103, and / or the second dividing groove is formed by extending from the edge of the third tab away from the third body towards the third body.

[0096] In the above technical solution, a plurality of first dividing grooves 105 extend from the top to the root of the first tab 104, dividing the first tab 104 into a plurality of first sub-tabs 106 arranged side by side on one side of the first body 103, so as to reduce the risk of cracking of the single tab edge due to large force during the welding process and improve the anti-cracking performance of the third tab. A plurality of second dividing grooves extend from the top to the root of the third tab, dividing the third tab into a plurality of third sub-tabs arranged side by side on one side of the third body, so as to reduce the risk of cracking of the single tab edge due to large force during the welding process and improve the anti-cracking performance of the third tab.

[0097] In some optional embodiments, the first tab 104 and the second tab 107 have the same shape, and the overlapping area of the first tab 104 and the second tab 107 is greater than 95% of the total area of the first tab 104. The first tab 104 and the third tab have the same shape, and the overlapping area of the first tab 104 and the third tab is greater than 95% of the total area of the first tab 104. The above structure can improve the connection stability between the tabs, reduce the space occupied by the tabs, and improve the energy density of the battery cell 7.

[0098] As Figure 8 shown, in some embodiments of the present application, the first body 103 includes a conductor 110 and an active material layer 111 disposed on the surface of the conductor 110 along the first direction X. The first electrode plate 101 further includes a first connection portion 112, the first connection portion 112 is connected to one side of the conductor 110 along the second direction Y, the second direction Y intersects the first direction X, and a plurality of sub-tabs are respectively connected to the first connection portion 112, and a first dividing groove 105 is formed between two adjacent sub-tabs. In the above structure, by providing the first connection portion 112, the connection strength between the first sub-tab 106 and the conductor 110 is improved, and the risk of the first sub-tab 106 falling off is reduced.

[0099] In some embodiments of the present application, at least two of the conductor 110, the first connecting portion 112, and the first sub-tab 106 are integrally formed structures. The above technical solution improves the connection strength between the first body 103, the first connecting portion 112, and the first sub-tab 106, and improves the overall structural strength of the first electrode tab 101.

[0100] In some alternative embodiments, the width of the first connecting portion 112 in the third direction Z is L1, and the width of the first body 103 in the third direction Z is L2, where 0.5*L2 ≤ L1 ≤ 0.8*L2.

[0101] In the above structure, the width of the first connecting portion 112 is limited within a reasonable range, which can ensure the current-carrying area of the first tab 104 and improve the structural strength of the connection between the first tab 104 and the first body 103.

[0102] In some embodiments of the present application, a plurality of first sub-tabs 106 are arranged at intervals in the third direction Z and are sequentially connected to the first connecting portion 112, and the third direction Z intersects the plane where the first direction X and the second direction Y are located.

[0103] In the above structure, a plurality of first sub-tabs 106 are arranged on one side of the conductor 110, which can effectively reduce the risk of cracking at the edge of the tab during the welding process and improve the structural stability of the first tab 104.

[0104] In an alternative embodiment, a plurality of first sub-tabs 106 are directly connected to the first body 103, that is, the first cutting groove extends from the edge of the first tab 104 to the first body 103 along the second direction Y.

[0105] In some embodiments of the present application, the battery cell 7 includes a housing 20 and an electrode assembly 10. The housing 20 has a receiving cavity, and the electrode assembly 10 is disposed in the receiving cavity. The electrode assembly 10 includes a first electrode tab 101 and a second electrode tab 102. The first electrode tab 101 includes a first body 103 and a first tab 104. A first dividing groove 105 is provided on the first tab 104. The first dividing groove 105 divides the first tab 104 into a plurality of first sub-tabs 106, and each first sub-tab 106 is respectively connected to the first body 103. The second electrode tab 102 is stacked with the first electrode tab 101. The second electrode tab 102 includes a second tab 107. Among them, the plurality of first sub-tabs 106 are respectively connected to the second tab 107. The number of the first electrode tabs 101 is two, the second electrode tab 102 is disposed between the two first electrode tabs 101, and any one second tab 107 is connected to at least two first sub-tabs 106. The electrode assembly 10 further includes a third electrode tab 109. The third electrode tab 109 includes a third body and a third tab. A second dividing groove is provided on the third tab to divide the third tab into a plurality of second sub-tabs. The second sub-tabs are electrically connected to the first sub-tabs 106. The number of the third electrode tabs 109 is multiple, and the multiple third electrode tabs 109 are stacked on a side of the first electrode tab 101 facing away from the second electrode tab 102. The number of the second electrode tabs 102 is two, and the two second electrode tabs 102 are respectively disposed corresponding to the two first electrode tabs 101. A plurality of single-tab electrode tabs are provided in the second electrode tab 102. A plurality of third electrode tabs 109 are provided outside the first electrode tab 101. Among them, the total number of layers of the inner second electrode tab 102 and the single-tab electrode tabs is 50-100 layers; the total number of layers of the single-sided first electrode tab 101 and the third electrode tabs 109 is 5-10 layers. The first dividing groove 105 is formed by extending from the edge of the first tab 104 away from the first body 103 towards the first body 103, and the second dividing groove is formed by extending from the edge of the third tab away from the third body towards the third body.

[0106] An embodiment of the present application provides an electrode assembly 10, which includes a first electrode tab 101 and a second electrode tab 102. The first electrode tab 101 includes a first body 103 and a first tab 104. A first dividing groove 105 is provided on the first tab 104. The first dividing groove 105 divides the first tab 104 into a plurality of first sub-tabs 106, and each first sub-tab 106 is respectively connected to the first body 103. The second electrode tab 102 is stacked with the first electrode tab 101. The second electrode tab 102 includes a second tab 107. Among them, the plurality of first sub-tabs 106 are respectively connected to the second tab 107.

[0107] In the above structure, a first dividing groove 105 is provided in the first pole piece 101 to divide the first tab 104 into a plurality of first sub-tabs 106, and a first tab 104 connecting member is provided between each first sub-tab 106 and the second tab 107 to connect the plurality of first sub-tabs 106 to the second tab 107 simultaneously. On the one hand, it can reduce the risk of explosion points, air bubbles and cracks in a single tab during the welding process; on the other hand, the plurality of first sub-tabs 106 are connected to the second tab 107 simultaneously, which can increase the structural strength of the connection between the first tab 104 and the second tab 107, and can also increase the current-carrying capacity between the first tab 104 and the second tab 107. In the case where a certain first sub-tab 106 is cracked, the other first sub-tabs 106 can still be normally electrically connected to the second tab 107, improving the operation stability of the battery cell 7.

[0108] An embodiment of the present application provides a battery 2, which includes the battery cell 7 in the above embodiment, or includes the electrode assembly 10 in the above embodiment. An embodiment of the present application also provides an electrical device, which includes the battery 2 in the above embodiment, and the battery 2 is used to provide electrical energy. The above battery 2 and the electrical device both include the electrode assembly 10 in the above embodiment, and therefore also have the above technical effects, which will not be elaborated here.

[0109] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be covered by the scope of the claims and the specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell (7), characterized in that: An electrode assembly (10) is provided, wherein the electrode assembly (10) comprises: A first pole piece (101) comprises a first body (103) and a first pole tab (104), wherein the first pole tab (104) is provided with a first dividing groove (105), wherein the first dividing groove (105) divides the first pole tab (104) into a plurality of first sub-pole tabs (106), and each of the first sub-pole tabs (106) is respectively connected to the first body (103); A second pole piece (102) is stacked with the first pole piece (101), wherein the second pole piece (102) comprises a second pole lug (107). Wherein, a plurality of the first sub-electrode tabs (106) are respectively connected to the second electrode tabs (107).

2. The battery cell (7) according to claim 1, characterized in that: The number of the first pole pieces (101) is two, the second pole piece (102) is arranged between the two first pole pieces (101), and any one of the second pole tabs (107) is connected to at least two of the first sub-pole tabs (106).

3. The battery cell (7) according to claim 1 or 2, characterized in that: The electrode assembly (10) further comprises a third pole piece (109), the third pole piece (109) comprising a third body and a third pole ear, the third pole ear being provided with a second dividing groove to divide the third pole ear into a plurality of second sub-pole ears, the second sub-pole ears being electrically connected to the first sub-pole ear (106), the number of the third pole pieces (109) being multiple, and the plurality of third pole pieces (109) being stacked and arranged on a side of the first pole piece (101) facing away from the second pole piece (102).

4. The battery cell (7) according to claim 3, characterized in that: The orthographic projection of the second dividing groove on the first pole piece (101) at least partially overlaps with the first dividing groove (105).

5. The battery cell (7) according to claim 3, characterized in that: The thickness of the first pole tab (104) is greater than the thickness of the second pole tab (107), and / or the thickness of the third pole tab is greater than the thickness of the second pole tab (107).

6. The battery cell (7) according to claim 5, characterized in that: The thickness of the first pole tab (104) is H1, the thickness of the second pole tab (107) is H2, and the thickness of the third pole tab is H3. H1, H2 and H3 satisfy the relationship: H2<H1≤5H2, and / or H2<H3≤5H2.

7. The battery cell (7) according to claim 3, characterized in that: The first dividing groove (105) is formed by extending along the edge of the first pole ear (104) away from the first body (103) toward the first body (103), and / or the second dividing groove is formed by extending along the edge of the third pole ear away from the third body toward the third body.

8. The battery cell (7) according to claim 1 or 2, characterized in that: The first body (103) comprises a conductor (110) and an active material layer (111) arranged on the surface of the conductor (110) along a first direction (X), and the first pole piece (101) further comprises: A first connecting portion (112) is connected to one side of the conductor (110) along a second direction (Y), wherein the second direction (Y) intersects with the first direction (X), and a plurality of the first sub-pole ears (106) are respectively connected to the first connecting portion (112), and a first dividing groove (105) is formed between two adjacent first sub-pole ears (106).

9. The battery cell (7) according to claim 8, characterized in that: At least two of the conductor (110), the first connecting portion (112) and the first sub-electrode tab (106) are integrally formed structures.

10. The battery cell (7) according to claim 8, characterized in that: The plurality of first sub-electrode tabs (106) are arranged at intervals along a third direction (Z) and are sequentially connected to the first connecting portion (112), and the third direction (Z) intersects with a plane where the first direction (X) and the second direction (Y) are located.

11. An electrode assembly (10), characterized in that: include: A first pole piece (101) comprises a first body (103) and a first pole tab (104), wherein the first pole tab (104) is provided with a first dividing groove (105), wherein the first dividing groove (105) divides the first pole tab (104) into a plurality of first sub-pole tabs (106), and each of the first sub-pole tabs (106) is respectively connected to the first body (103); A second pole piece (102) is stacked with the first pole piece (101), wherein the second pole piece (102) comprises a second pole lug (107). Wherein, a plurality of the first sub-electrode tabs (106) are respectively connected to the second electrode tabs (107).

12. A battery (2), characterized in that: The method comprises a battery cell (7) as claimed in any one of claims 1 to 10, or an electrode assembly (10) as claimed in claim 11.

13. An electrical device, characterized in that: The electrical device comprises the battery (2) as claimed in claim 12, and the battery (2) is used to provide electrical energy.

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