Electrode assembly, battery cell, battery, and electrical device

Abstract

An electrode assembly, a battery cell, a battery, and an electrical device. The electrode assembly comprises a main body, a plurality of tabs are led out from an end of the main body, and the plurality of tabs are stacked; the part of at least one tab close to the main body is provided with a weakening structure, and the weakening structure is used for reducing the structural strength of the part of the tab close to the main body, so that the part of the tab close to the main body is easy to bend, thereby reducing the stress generated when the tabs are folded, reducing the pulling force caused by stress release to the tabs in a subsequent welding process, alleviating cracking and fragmenting of the tabs, improving the performance of the battery cell.

Description

Electrode assembly, battery cell, battery and electrical device

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on July 25, 2023, with application number 202310920754.8 and invention name “Electrode assembly, battery cell, battery and electrical device”, the entire contents of which are incorporated by reference into this application. Technical Field

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

[0003] A battery cell usually includes a shell and an electrode assembly. The electrode assembly includes a main body and multiple tabs extending from the ends of the main body. The multiple tabs are electrically connected to the electrode terminals on the shell, thereby realizing the output and input of electrical energy of the battery cell. During the production process of the battery cell, when the multiple tabs are gathered and welded, the tabs are prone to cracking and debris, affecting the reliability of the battery cell.

[0004] The above statements are only used to provide background information related to the present application and do not necessarily constitute prior art.

[0005] Application Contents

[0006] The purpose of the embodiments of the present application is to provide an electrode assembly, a battery cell, a battery and an electrical device, including but not limited to solving the problem in the related art that when multiple tabs are folded and welded together, the tabs are prone to cracking and debris.

[0007] The technical solution adopted in the embodiment of this application is:

[0008] In a first aspect, an electrode assembly is provided, which includes a main body, a plurality of tabs extending from the end of the main body, and the plurality of tabs are stacked; wherein, at least one tab is provided with a weakening structure at a portion close to the main body, and the weakening structure is used to reduce the structural strength of the portion of the tab close to the main body.

[0009] The electrode assembly of the embodiment of the present application includes a main body, and a plurality of stacked tabs are extended from the end of the main body, and a weakening structure is provided at the portion of at least one tab close to the main body. The weakening structure can reduce the structural strength of the portion of the tab close to the main body, so that the portion of the tab close to the main body is easy to bend, reducing the stress generated by the tab when it is folded, reducing the pulling force on the tab caused by the stress release during subsequent welding, improving the cracking and debris of the tab, and improving the performance of the battery cell.

[0010] In one embodiment, a plurality of stacked tabs form a tab portion; in the stacking direction of the plurality of tabs, at least the tab close to the outer side of the tab portion is provided with a weakening structure.

[0011] By adopting the technical solution of this embodiment, after the multiple tabs are folded together, the tabs near the outer side of the tab portion are subject to large bending deformation and stress, while the tabs near the outer side of the tab portion are provided with a weakening structure, which can effectively reduce the stress of the tabs near the outer side of the tab portion and effectively improve the cracking and debris conditions of the tabs.

[0012] In one embodiment, the number of tabs provided with the weakening structure is N1, and the total number of tabs is N2, wherein 0<N1 / N2≤0.2.

[0013] By adopting the technical solution of this embodiment, the design of 0<N1 / N2≤0.2 makes it possible that when the total number of tabs is constant, the proportion of tabs with weakening structures is small, that is, the number of tabs with weakening structures in the tabs is small, which can facilitate the production of pole pieces.

[0014] In one embodiment, 0.05≤N1 / N2≤0.1.

[0015] By adopting the technical solution of this embodiment, the design of 0.05≤N1 / N2≤0.1 makes it possible to have a reasonable proportion of the pole ears with weakening structures when the total number of pole ears is certain, that is, the number of pole ears with weakening structures in the pole ears is reasonable, which can effectively alleviate the cracking and debris of the pole ears, and the production of the pole sheets is also simpler and faster.

[0016] In one embodiment, the number of tabs provided with the weakening structure is N1, where 1≤N1≤20.

[0017] By adopting the technical solution of this embodiment and the design of 1≤N1≤20, the number of tabs provided with weakening structures is reduced, which can facilitate the production of the pole piece.

[0018] In one embodiment, 5≤N1≤15.

[0019] By adopting the technical solution of this embodiment, 5≤N1≤15, a reasonable number of tabs with weakening structures are provided in the tabs, which can effectively alleviate the cracking and debris of the tabs, and the production of the pole pieces is also simpler and faster.

[0020] In one embodiment, the weakened structure includes at least one of a hollow structure or a thinned structure.

[0021] By adopting the technical solution of this embodiment, the weakening structure has a variety of structures to be applicable to different types of tabs, so as to better improve the tab cracking and chipping conditions.

[0022] In one embodiment, when the weakened structure includes a hollow structure, the hollow structure is a through hole.

[0023] By adopting the technical solution of this embodiment, the hollow structure adopts a through-hole structure, which can effectively reduce the structural strength of the tab, reduce the stress generated by the bending of the tab, and effectively improve the cracking and debris of the tab; in addition, the through-hole structure is simple and easy to process and manufacture.

[0024] In one embodiment, the through hole includes at least one of an elongated hole, a wavy hole, a circular hole or a polygonal hole.

[0025] By adopting the technical solution of this embodiment, the shape of the through hole is more regular, which is convenient for processing and manufacturing.

[0026] In one embodiment, the distance between the weakened structure and the active material of the electrode assembly is L, wherein 5 mm ≤ L ≤ 25 mm.

[0027] By adopting the technical solution of this embodiment, the setting of 5mm≤L≤25mm allows a certain distance to exist between the weakened structure and the active material, which can reduce the risk of the tab cracking to the active material coating area, and is beneficial to improving the reliability of the battery cell; in addition, a certain distance can be created between the weakened structure and the welding area of ​​the tab, which has good welding strength and is also beneficial to alleviating the cracking and debris of the tab, thereby improving the performance of the battery cell.

[0028] In one embodiment, 10 mm ≤ L ≤ 20 mm.

[0029] By adopting the technical solution of this embodiment, the setting of 10mm≤L≤20mm allows a reasonable distance between the weakened structure and the active material, thereby effectively reducing the risk of the tab cracking to the active material coating area and effectively improving the reliability of the battery cell.

[0030] In one embodiment, the weakened structure is in the shape of an elongated strip.

[0031] By adopting the technical solution of this embodiment, the setting of 10mm≤L≤20mm allows a reasonable distance between the weakened structure and the active material, which effectively reduces the risk of the tab cracking to the active material coating area and effectively improves the reliability of the battery cell. In addition, the spacing between the weakened structure and the welding area of ​​the tab can be set more reasonably, which is conducive to improving the welding strength, and can also effectively alleviate the cracking and debris of the tab and improve the performance of the battery cell.

[0032] In one embodiment, the weakening structure forms a preset angle with the end surface of the main body, and the preset angle is A, wherein 0°≤A≤30°.

[0033] By adopting the technical solution of this embodiment, the design of 0°≤A≤30° makes the inclination angle of the length direction of the weakening structure relative to the edge of the current collector smaller. In this way, the tab cracks along the length direction of the weakening structure and is not likely to crack into the active material coating area, thereby reducing the risk of active material falling off the current collector, which is beneficial to improving the reliability of the battery cell.

[0034] In one embodiment, 0°≤A≤10°.

[0035] By adopting the technical solution of this embodiment, the design of 0°≤A≤30° makes the inclination angle of the length direction of the weakening structure relative to the edge of the current collector smaller, so that the tab is less likely to crack along the length direction of the weakening structure and to crack into the current collector area, which can effectively reduce the risk of active materials on the current collector falling off and effectively alleviate the debris situation.

[0036] In one embodiment, the weakening structure is located between two opposite sides of the tab in the width direction.

[0037] By adopting the technical solution of this embodiment, the structural strength of the tab at both ends of the weakened structure is good, which can reduce the risk of the tab breaking at the weakened structure.

[0038] In one embodiment, in the width direction of the tab, the dimension of the weakened structure is W1, and the maximum dimension of the tab is W2, wherein 0<W1 / W2≤0.8.

[0039] By adopting the technical solution of this embodiment, with a design where 0 < W1 / W2 ≤ 0.8, the weakened structure can reduce the structural strength of the tab near the main body, reducing the risk of tab cracking due to stress release. At the same time, the tab also has a certain degree of structural strength at the weakened structure, reducing the risk of tab fracture at the weakened structure. Furthermore, the tab has a large cross-sectional area at the weakened structure, providing excellent current flow capacity and meeting the requirements of rapid charging and discharging.

[0040] In one embodiment, 0<W1 / W2≤0.5.

[0041] By adopting the technical solution of this embodiment, with a design of 0 < W1 / W2 ≤ 0.5, the weakening structure has a more reasonable proportion across the width of the tab. This allows the weakening structure to reduce the structural strength of the portion of the tab near the main body, thus reducing the risk of tab cracking due to stress release. The tab also maintains reasonable structural strength at the weakening structure, effectively reducing the risk of tab fracture at the weakening structure. Furthermore, the tab has a larger cross-sectional area at the weakening structure, providing excellent current flow capacity and better meeting the requirements of rapid charging and discharging.

[0042] In one embodiment, in the width direction of the tab, the size of the weakened structure is W1, 4 mm ≤ W1 ≤ 80 mm.

[0043] By adopting the technical solution of this embodiment, the design of 4mm≤W1≤80mm, the size of the weakening structure in the width direction of the pole ear is reasonably set, so that the weakening structure can reduce the structural strength of the part of the pole ear close to the main body and reduce the cracking of the pole ear due to stress release. At the same time, the pole ear also has a certain structural strength at the weakening structure, reducing the risk of the pole ear breaking at the weakening structure; in addition, the cross-sectional area of ​​the pole ear at the weakening structure is large, and the current flow capacity of the pole ear is good, which can meet the requirements of fast charging and discharging.

[0044] In one embodiment, 10 mm ≤ W1 ≤ 50 mm.

[0045] By adopting the technical solution of this embodiment, the design of 10mm≤W1≤50mm, the size setting of the weakening structure in the width direction of the pole ear is more reasonable, so that the weakening structure can reduce the structural strength of the part of the pole ear close to the main body and reduce the cracking of the pole ear due to stress release. The pole ear also has a more reasonable structural strength at the weakening structure, thereby effectively reducing the risk of the pole ear breaking at the weakening structure; in addition, the cross-sectional area of ​​the pole ear at the weakening structure is also larger, and the current flow capacity of the pole ear is good, which can better meet the requirements of fast charging and discharging.

[0046] In one embodiment, in the height direction of the tab, the size of the weakened structure is H1, and the size of the tab is H2, wherein 0

[0047] By adopting the technical solution of this embodiment, the design of 0

[0048] In one embodiment, 0.01

[0049] By adopting the technical solution of this embodiment, the design of 0.01

[0050] In a second aspect, a battery cell is provided, comprising the electrode assembly according to the above embodiment.

[0051] ​​​​In a third aspect, a battery is provided, comprising the battery cell according to the above embodiment.

[0052] In a fourth aspect, an electrical device is provided, comprising a battery according to the above embodiment.

[0053] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0055] FIG1 is a schematic structural diagram of a vehicle provided in one embodiment of the present application.

[0056] FIG2 is a schematic structural diagram of a battery provided in another embodiment of the present application.

[0057] FIG3 is a schematic structural diagram of a battery cell provided in yet another embodiment of the present application.

[0058] FIG4 is a cross-sectional view of a battery cell provided in yet another embodiment of the present application.

[0059] FIG5 is a schematic structural diagram of the electrode assembly shown in FIG4 .

[0060] FIG6 is a cross-sectional view taken along line AA in FIG5 .

[0061] FIG7 is a cross-sectional view along line BB in FIG5 .

[0062] FIG8 is a partial enlarged view of point C in FIG7 .

[0063] FIG9 is a partial enlarged view of point D in FIG7 .

[0064] FIG10 is a schematic diagram of the structure of an electrode piece in an electrode assembly provided in yet another embodiment of the present application.

[0065] FIG11 is a schematic structural diagram of an electrode piece in an electrode assembly provided in yet another embodiment of the present application.

[0066] FIG12 is a schematic structural diagram of an electrode piece in an electrode assembly provided in yet another embodiment of the present application.

[0067] FIG13 is an exploded schematic diagram of a battery cell provided in yet another embodiment of the present application.

[0068] FIG14 is a schematic structural diagram of the electrode assembly shown in FIG13 .

[0069] FIG15 is a cross-sectional view taken along line EE in FIG14.

[0070] FIG16 is a partial enlarged view of point F in FIG15 .

[0071] In the figures, the reference numerals are: 1000, vehicle; 1100, battery; 1200, controller; 1300, motor; 10, housing; 11, first part; 12, Part 2; 20. Battery cell; 21. End cap; 211. Electrode terminal; 212. Pressure relief mechanism; 213. Insulator; 22. Shell; 23. Electrode assembly; 231. Main body; 232. Ear; 232a. Positive ear; 232b. Negative ear; 233. Pole sheet; 233a. Positive electrode sheet; 233b. Negative electrode sheet; 2331. Current collector; 2331a. Positive current collector; 2331b. Negative current collector; 2332. Active material; 2332a. Positive active material; 2332b. Negative active material; 2333. Ear; 2333a. Positive electrode ear; 2333b. Negative electrode ear; 23331. Weakening structure; 234. Isolator; 24. Adapter. DETAILED DESCRIPTION

[0072] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, this application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0073] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art 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-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0074] In the description of the embodiments of this application, the technical terms "first," "second," etc., are used solely to distinguish between different objects and should not be understood to indicate or imply relative importance, or to implicitly specify the quantity, specific order, or primary-secondary relationship of the technical features indicated. Therefore, a feature designated "first" or "second" may explicitly or implicitly include one or more of such features.

[0075] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments in any suitable manner.

[0076] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0077] In the description of the embodiments of this application, the term "plurality" refers to two or more (including two). Similarly, "multiple groups" refers to two or more (including two groups), and "multiple sheets" refers to two or more (including two sheets). "Several" means one or more, unless otherwise specifically defined.

[0078] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limiting the embodiments of the present application.

[0079] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0080] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, when an element is referred to as being “fixed to” or “disposed on” another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or indirectly connected to the other element.

[0081] A battery cell can refer to the smallest electrical energy storage unit in a battery. A battery cell typically includes a housing, an electrode assembly, an electrolyte, and other components. The housing has a space for accommodating the electrode assembly and electrolyte. The electrode assembly can refer to the component in the battery cell where chemical reactions occur. The electrode assembly includes a pole piece and a separator, which are stacked and form a main body. The pole piece extends from the end face of the main body (see the surface indicated by arrow G in Figure 5). The housing is provided with electrode terminals, which are used to electrically connect the pole piece and external electrical components to achieve the output and input of electrical energy. In order to meet the requirements of fast charging and high-rate performance of the battery cell, the electrode assembly typically has multiple pole pieces, which are stacked and electrically connected to the electrode terminals.

[0082] In actual production, multiple tabs are stacked and welded together, then connected to an adapter sheet. The adapter sheet is then connected to the electrode terminal, completing the connection between the multiple tabs and the electrode terminal. During this process, the ends of the stacked tabs facing away from the main body are gathered together, causing the portion of the tab near the main body to bend and experience significant stress. During subsequent welding, this stress releases near the main body, pulling on the tabs. This can cause the tabs to crack, or even tear and produce debris, severely impacting the performance of the battery cells. Ultrasonic welding of multiple tabs is particularly prone to cracking in the weld mark area and tab debris, with cracking being particularly severe at the edges of the weld mark area and the edges of the active material.

[0083] In order to alleviate the cracking of the tabs, an embodiment of the present application proposes an electrode assembly, which includes a main body, and a plurality of tabs arranged in a stacked manner are led out from the end of the main body, and a weakening structure is provided at a portion of at least one tab close to the main body. The weakening structure can reduce the structural strength of the portion of the tab close to the main body, so that the portion of the tab close to the main body is easy to bend, reducing the stress generated by the tab when it is folded, reducing the pulling force on the tab caused by the stress release during subsequent welding, improving the cracking and debris of the tab, and improving the performance of the battery cell.

[0084] The electrode assemblies, battery cells, batteries, and electrical devices using the batteries as power sources disclosed in the embodiments of the present application may include, but are not limited to, mobile phones, tablets, laptop computers, electric toys, power tools, battery-powered vehicles, electric vehicles, ships, spacecraft, and the like. Electric toys may include fixed or mobile electric toys, such as game consoles, electric vehicle toys, electric ship toys, and electric airplane toys, and spacecraft may include airplanes, rockets, space shuttles, and spacecraft, among others.

[0085] For the convenience of description, the following embodiments are described by taking a vehicle 1000 as an example of an electrical device according to an embodiment of the present application.

[0086] Please refer to Figure 1, which is a schematic structural diagram of a vehicle 1000 provided in some embodiments of the present application. The vehicle 1000 can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 1100 is provided inside the vehicle 1000, and the battery 1100 can be provided at the bottom, head or tail of the vehicle 1000. The battery 1100 can be used to power the vehicle 1000. For example, the battery 1100 can serve as an operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 1200 and a motor 1300. The controller 1200 is used to control the battery 1100 to power the motor 1300, for example, for starting, navigating and driving the vehicle 1000.

[0087] In some embodiments of the present application, the battery 1100 can serve not only as an operating power source for the vehicle 1000, but also as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0088] Referring to Figure 2 , an embodiment of a battery 1100 includes a housing 10 and battery cells 20, with the battery cells 20 housed within the housing 10. The housing 10 provides a storage space for the battery cells 20 and can have various structures. In some embodiments, the housing 10 can include a first portion 11 and a second portion 12, which overlap each other and together define a storage space for the battery cells 20. The second portion 12 can be a hollow structure with one end open, and the first portion 11 can be a plate-like structure, overlapping the open side of the second portion 12, so that the first and second portions 11 and 12 together define a storage space. Alternatively, the first and second portions 11 and 12 can each be a hollow structure with one end open, with the open side of the first portion 11 overlapping the open side of the second portion 12. Of course, the housing 10 formed by the first and second portions 11 and 12 can have various shapes, such as a cylinder or a rectangular parallelepiped.

[0089] In the battery 1100 , there may be multiple battery cells 20 , and the multiple battery cells 20 may be connected in series, in parallel, or in mixed connection. Mixed connection means that the multiple battery cells 20 are connected in both series and in parallel.

[0090] In one embodiment, multiple battery cells 20 may be directly connected in series, parallel, or hybrid, and the entire battery cell 20 may then be housed within the housing 10. Alternatively, the battery 1100 may be constructed by first connecting multiple battery cells 20 in series, parallel, or hybrid to form a battery module, which is then connected in series, parallel, or hybrid to form a complete battery module, and then housed within the housing 10. The battery 1100 may also include other structures, such as a busbar assembly for electrically connecting the multiple battery cells 20.

[0091] Each battery cell 20 may be a secondary battery or a primary battery, and may also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 20 may be cylindrical, flat, rectangular, or in other shapes.

[0092] As another embodiment of the battery 1100 , the battery 1100 may not include the housing 10 , but may be assembled into an electrical device by electrically connecting a plurality of battery cells 20 and forming a whole with necessary fixing structures.

[0093] Please refer to Figure 3, which is a schematic diagram of the structure of a battery cell 20 provided in some embodiments of the present application. Figure 4 is a schematic cross-sectional diagram of a battery cell 20 provided in some embodiments of the present application. A battery cell 20 is the smallest unit that makes up a battery. As shown in Figure 3, a battery cell 20 includes an end cap 21, a housing 22, and an electrode assembly 23.

[0094] The end cap 21 refers to a component that covers the opening of the shell 22 to isolate the internal environment of the battery cell 20 from the external environment. Without limitation, the shape of the end cap 21 can be adapted to the shape of the shell 22 to match the shell 22. Optionally, the end cap 21 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the end cap 21 is not easily deformed when squeezed or collided, so that the battery cell 20 can have a higher structural strength and the safety performance can also be improved. The material of the end cap 21 can also be a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiments of the present application do not impose any special restrictions on this.

[0095] The housing 22 is a component that cooperates with the end cap 21 to form the internal environment of the battery cell 20. This internal environment can be used to accommodate the electrode assembly 23, electrolyte, and other components. The housing 22 and end cap 21 can be separate components. An opening can be provided in the housing 22, and the end cap 21 is placed over the opening to form the internal environment of the battery cell 20. Alternatively, the end cap 21 and housing 22 can be integrated. Specifically, the end cap 21 and housing 22 can form a common connection surface before other components are inserted into the housing. When the interior of the housing 22 needs to be enclosed, the end cap 21 is placed over the housing 22. The housing 22 can have a variety of shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, or a hexagonal prism. Specifically, the shape of the housing 22 can be determined based on the specific shape and size of the electrode assembly 23. The housing 22 can be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this embodiment of the present application does not impose any particular limitations on this.

[0096] As shown in Figures 5, 6, and 7, the electrode assembly 23 is the component in the battery cell 20 where the electrochemical reaction occurs. The housing 22 may contain one or more electrode assemblies 23. The electrode assembly 23 includes a pole piece 233 and a separator 234. The pole piece 233 includes a current collector 2331, an active material 2332 disposed on at least one surface of the current collector 2331, and a tab 2333 extending from the edge of the current collector 2331 (see the edge indicated by arrow T1 in Figure 10). The surface of the tab 2333 may be partially coated with the active material 2332 (as shown in Figure 11, the entire surface below the dotted line in Figure 11 is coated with the active material 2332), or may not be coated with the active material 2332 (as shown in Figure 10, the entire surface below the dotted line in Figure 10 is coated with the active material 2332). The pole piece 233 is divided into a positive pole piece 233a and a negative pole piece 233b. During the charge and discharge process of the battery cell 20, active ions (such as lithium ions) are inserted and removed between the positive electrode sheet 233a and the negative electrode sheet 233b. The separator 234 is provided between the positive electrode sheet 233a and the negative electrode sheet 233b to prevent a short circuit between the positive and negative electrodes while allowing the active ions to pass through.

[0097] In some embodiments, please refer to Figures 7, 8 and 9. The positive electrode sheet 233a may include a positive electrode collector 2331a, a positive electrode active material 2332a provided on at least one surface of the positive electrode collector 2331a, and a positive electrode tab 2333a extending from the edge of the positive electrode collector 2331a. The surface of the positive electrode tab 2333a may be partially coated with the positive electrode active material 2332a, or may not be coated with the positive electrode active material 2332a at all. The positive electrode tab 2333a may be distributed on one side of the positive electrode collector 2331a, or may be respectively on two opposite sides of the positive electrode collector 2331a. There are multiple positive electrode tabs 2333a, and the multiple positive electrode tabs 2333a are spaced apart along the length direction of the positive electrode collector 2331a.

[0098] In some embodiments, please refer to Figures 9, 10 and 11 together, the negative electrode sheet 233b may include a negative electrode current collector 2331b, a negative electrode active material 2332b provided on at least one surface of the negative electrode current collector 2331b, and a negative electrode tab 2333b extending from the edge of the negative electrode current collector 2331b. The surface of the negative electrode tab 2333b may be partially coated with the negative electrode active material 2332b, or may not be coated with the negative electrode active material 2332b at all. The negative electrode tab 2333b may be distributed on one side of the negative electrode current collector 2331b, or may be respectively on opposite sides of the negative electrode current collector 2331b. There are multiple negative electrode tabs 2333b, and the multiple negative electrode tabs 2333b are spaced apart along the length direction of the negative electrode current collector 2331b.

[0099] In some embodiments, the separator 234 is a separator. The present application has no particular limitation on the type of separator, and any known separator with a porous structure having good chemical stability and mechanical stability can be selected.

[0100] In one embodiment, as shown in Figures 5, 6 and 7, the electrode assembly 23 is a wound structure, and the positive electrode sheet 233a, the negative electrode sheet 233b and the separator 234 are wound into a wound structure. For example, it can be wound into a cylindrical structure, or it can be wound into a flat sheet structure, or it can be wound into a cylindrical structure and then hot-pressed into a flat sheet structure. For example, during the winding process, the negative electrode sheet 233b, the positive electrode sheet 233a and the separator 234 are stacked together and then wound. After the winding is completed, the positive electrode collector 2331a, the negative electrode collector 2331b and the separator 234 are wound to form the main body 231 of the electrode assembly 23, and multiple positive electrode tabs 2333a are gathered and stacked to form the positive electrode tab 232a, and multiple negative electrode tabs 2333b are also gathered and stacked to form the negative electrode tab 232b; wherein, the positive electrode tab 232a and the negative electrode tab 232b can be located on the same side of the main body 231 (as shown in Figure 14), or they can be arranged on opposite sides of the main body 231 (as shown in Figure 5).

[0101] In one embodiment, the electrode assembly 23 has a stacked structure, with the positive electrode sheet 233a, separator 234, negative electrode sheet 233b, and separator 234 alternately stacked in sequence to form the stacked electrode assembly 23. After the stacking is completed, the positive electrode current collector 2331a, negative electrode current collector 2331b, and separator 234 are wound to form the main body 231 of the electrode assembly 23. Multiple positive electrode tabs 2333a are stacked together to form the positive electrode tab portion 232a, and multiple negative electrode tabs 2333b are stacked together to form the negative electrode tab portion 232b. The stacking of multiple tabs 2333 in the tab portion 232 also facilitates electrical connection to the electrode terminal 211.

[0102] In one embodiment, as shown in FIG4 and FIG5, the end cap 21 is provided with an electrode terminal 211, the end cap 21 is provided with a mounting hole, the electrode terminal 211 is provided with an insulating member 213 on the outer cover, and the insulating member 213 is passed through the mounting hole to achieve insulation between the end cap 21 and the electrode terminal 211, and the pole ear portion 232 is connected to the adapter 24 and then connected to the electrode terminal 211; through the switching effect of the adapter 24, the pole ear portion 232 and the electrode terminal 211 at different positions can also be connected; for example, the electrode The assembly 23 has tabs 232 extending from both sides. The tabs 232 on the sides are electrically connected to the electrode terminals 211 located at the top via L-shaped adapters 24. In another embodiment, the tabs 232 extending from the top of the electrode assembly 23 are electrically connected directly to the electrode terminals 211 located at the top via adapters 24. In other embodiments, the electrode terminals 211 can also be located on the sidewalls of the housing 22, with the specific design depending on actual needs. There are two electrode terminals 211, each electrically connected to the positive and negative tabs 232a and 232b via adapters 24, respectively. The end cap 21 can also be provided with a pressure relief mechanism 212 to promptly discharge high-pressure gas generated during the charging and discharging process of the battery cell 20, thereby improving the reliability of the battery cell 20. The pressure relief mechanism 212 can also be located on the sidewalls of the housing 22.

[0103] Please refer to Figures 5, 6 and 7. In one embodiment of the present application, an electrode assembly 23 is provided. The electrode assembly 23 includes a main body 231, and a plurality of pole ears 2333 are led out from the end of the main body 231. The plurality of pole ears 2333 are stacked; wherein, at least one pole ear 2333 is provided with a weakening structure 23331 near the main body 231, and the weakening structure 23331 is used to reduce the structural strength of the portion of the pole ear 2333 near the main body 231.

[0104] The body portion 231 may refer to a portion in which the current collector 2331 and the separator 234 in the electrode assembly 23 are stacked or wound.

[0105] A plurality of pole tabs 2333 are led out from the end of the main body 231, and the plurality of pole tabs 2333 are stacked; it can be understood that after the current collector 2331 is wound or stacked to form the main body 231, the plurality of pole tabs 2333 led out from the edge of the current collector 2331 are stacked and gathered at the end of the main body 231, so as to facilitate the electrical connection of the plurality of pole tabs 2333 with the adapter 24 after they are folded together; wherein, the pole tab 2333 may refer to a component protruding from the edge of the current collector 2331 of the electrode piece 233. In one embodiment, the current collector 2331 and the tab 2333 can be an integrated structure. For example, during the production process of the electrode 233, the integrated current collector 2331 and the tab 2333 can be directly obtained by die-cutting the electrode 233 raw material. The current collector 2331 and the tab 2333 can also be separate structures. For example, the tab 2333 is welded to the edge of the current collector 2331. The tab 2333 can be distributed on one side of the current collector 2331 or on both sides of the current collector 2331. The material of the current collector 2331 and the tab 2333 can be the same or different, such as copper, aluminum, etc. Among them, when the electrode 233 is a positive electrode electrode 233a, the current collector 2331 of the electrode 233 is a positive electrode current collector 2331a, the electrode ear 2333 of the electrode 233 is a positive electrode electrode ear 2333a, the active material 2332 of the electrode 233 is a positive electrode active material 2332a, and the electrode ear portion 232 formed by the multiple stacked electrode ears 2333 of the electrode 233 is a positive electrode electrode ear portion 232a; when the electrode 233 is a negative electrode electrode 233b, the current collector 2331 of the electrode 233 is a negative electrode current collector 2331b, the electrode ear 2333 of the electrode 233 is a negative electrode electrode ear 2333b; the active material 2332 of the electrode 233 is a negative electrode active material 2332b, and the electrode ear portion 232 formed by the multiple stacked electrode ears 2333 of the electrode 233 is a negative electrode electrode ear portion 232b.

[0106] At least one pole lug 2333 is provided with a weakening structure 23331 at a portion close to the main body 231. It can be understood that, among the multiple pole lugs 2333, a portion of the pole lugs 2333 may be provided with a weakening structure 23331, and another portion of the pole lugs 2333 may not be provided with a weakening structure 23331; or all of the pole lugs 2333 may be provided with a weakening structure 23331; the weakening structure 23331 is located at a portion of the pole lug 2333 close to the main body 231, and the weakening structure 23331 can reduce the structural strength of the portion of the pole lug 2333 close to the main body 231. In other words, the structural strength of the position of the pole lug 2333 provided with the weakening structure 23331 is lower than the structural strength of other positions of the pole lug 2333. Among them, the part of the pole tab 2333 close to the main body 231 may refer to the part of the pole tab 2333 that is curved after being folded, or may refer to the part of the pole tab 2333 located between the welding area and the current collector 2331. It should be noted that the welding area may refer to a welding structure formed by welding multiple pole tabs 2333 into a whole, and the area occupied by the welding structure on the pole tab 2333; the welding structure may be a weld seam, a weld mark or other structures.

[0107] After the multiple pole tabs 2333 are gathered and stacked, the ends of the multiple pole tabs 2333 facing away from the main body 231 are gathered and bent to facilitate the welding of the multiple pole tabs 2333. After the pole tabs 2333 are gathered and bent, the portion of the pole tab 2333 close to the main body 231 may bend and generate greater stress. The portion of the pole tab 2333 close to the main body 231 is provided with a weakening structure 23331. The weakening structure 23331 can reduce the structural strength of the portion of the pole tab 2333 close to the main body 231, making the portion easier to bend. At the same time, the stress generated after the pole tab 2333 close to the main body 231 is small, the stress is released during welding, and the pole tab 2333 is subjected to small pulling force, which is conducive to improving the cracking and debris of the pole tab 2333.

[0108] The electrode assembly 23 of the embodiment of the present application includes a main body 231, and a plurality of stacked tabs 2333 are extended from the end of the main body 231, and a weakening structure 23331 is provided on the portion of at least one tab 2333 close to the main body 231. The weakening structure 23331 can reduce the structural strength of the portion of the tab 2333 close to the main body 231, so that the portion of the tab 2333 close to the main body 231 is easy to bend, reducing the stress generated by the tab 2333 when it is folded, reducing the pulling force on the tab 2333 caused by the stress release during subsequent welding, improving the cracking and debris of the tab 2333, and improving the performance of the battery cell 20.

[0109] It should be noted that, in conjunction with Figures 4 to 9 and 14 to 16, the electrode assembly 23 formed by winding or stacking the electrode pieces 233 and the separators 234, the main body 231 of the electrode assembly 23 is flat, the height direction of the main body 231 can refer to the Z direction in the figure, the length direction of the main body 231 can refer to the X direction in the figure, and the thickness direction of the main body 231 can refer to the Y direction in the figure. In conjunction with Figures 10 to 12, before the electrode piece 233 is wound, the length direction of the electrode piece 233 can refer to the direction indicated by the arrow X1 in the figure, the height direction of the electrode piece 233 can refer to the direction indicated by the arrow Y1 in the figure, the width direction of the electrode tab 2333 can refer to the direction indicated by the arrow X1 in the figure, and the height direction of the electrode tab 2333 can refer to the direction indicated by the arrow Y1 in the figure. After the electrode assembly 23 is formed by winding or stacking the electrode piece 233 and the isolation member 234, the width direction of the electrode tab 2333 can be referred to the X direction in the figure, the height direction of the electrode tab 2333 can be referred to the Z direction in the figure, and the thickness direction of the electrode tab 2333 can be referred to the Y direction in the figure.

[0110] In one embodiment, as shown in Figures 7 and 8 , the thickness t1 of the positive electrode tab 2333a ranges from 8um to 20um. This ensures that the positive electrode tab 232a, after being welded, has a suitable thickness for connection to the adapter 24. Furthermore, the collapsed positive electrode tab 232a has a suitable cross-sectional area, and the collapsed positive electrode tab 232a has good current capacity to meet the requirements of fast charge and discharge and high-rate performance. The value of t1 can be, but is not limited to, 8um, 10um, 12um, 14um, 16um, 18um, or 20um.

[0111] In one embodiment, as shown in Figures 7 and 9 , the thickness t2 of the negative electrode tab 2333b ranges from 4 μm to 12 μm. This ensures that the negative electrode tab 232b, after being gathered and welded, has an appropriate thickness for connection to the adapter 24. Furthermore, the gathered negative electrode tab 232b has an appropriate cross-sectional area, providing good current capacity to meet the requirements of fast charge and discharge and high-rate performance. The value of t2 can be, but is not limited to, 4 μm, 6 μm, 8 μm, 10 μm, or 12 μm.

[0112] In one embodiment, as shown in FIG6 , the thickness t3 of the electrode assembly 23 ranges from 5 mm to 30 mm. The thickness of the electrode assembly 23 may refer to the thickness of the main body 231 , with the thickness of the main body 231 being oriented in the Y direction in the figure. The thickness t3 of the electrode assembly 23 is set within the above range. A reasonable design of the thickness t3 of the electrode assembly 23 facilitates chemical reactions in the electrode assembly 23 and improves the performance of the electrode assembly 23. The value of t3 may be, but is not limited to, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, or 30 μm.

[0113] In another embodiment of the present application, as shown in Figures 7, 8 and 9, a plurality of stacked tabs 2333 form a tab portion 232; in the stacking direction of the plurality of tabs 2333, at least the tab 2333 close to the outer side of the tab portion 232 is provided with a weakening structure 23331.

[0114] The pole ear portion 232 may refer to a component formed by stacking a plurality of pole ears 2333. The pole ear portion 232 is divided into a positive pole ear portion 232a and a negative pole ear portion 232b. A plurality of positive pole ears 2333a are stacked together to form the positive pole ear portion 232a, and a plurality of negative pole ears 2333b are stacked together to form the negative pole ear portion 232b.

[0115] The stacking direction of the plurality of tabs 2333 can be referred to the direction of arrow Y in FIG. 7 .

[0116] At least the pole lug 2333 close to the outer side of the pole lug portion 232 is provided with a weakening structure 23331. It can be understood that, in the stacking direction of multiple pole lugs 2333, the side of the first pole lug 2333 facing away from the pole lug 2333 adjacent to it is the outer side of the pole lug portion 232; and the side of the last pole lug 2333 facing away from the pole lug 2333 adjacent to it is also the outer side of the pole lug portion 232; specifically, the outer side of the pole lug portion 232 can refer to the side indicated by the arrow M in Figure 7; wherein, the first pole lug 2333 may be provided with the weakening structure 23331, or a part of the pole lug 2333 close to the first pole lug 2333 may be provided with the weakening structure 23331, or the last pole lug 2333 may be provided with the weakening structure 23331, or a part of the pole lug 2333 close to the last pole lug 2333 may be provided with the weakening structure 23331, and the specific setting can be based on actual conditions.

[0117] In one embodiment, when the electrode ear portion 232 is a positive electrode electrode ear portion 232a, a weakening structure 23331 is provided on the positive electrode electrode ear 2333a close to the side indicated by the right arrow M in Figure 7, and in the stacking direction of multiple positive electrode electrode ears 2333a (refer to the direction of arrow Y in Figure 7), the first positive electrode electrode ear 2333a and the last positive electrode electrode ear 2333a are provided with a weakening structure 23331; in another embodiment, when the electrode ear portion 232 is a negative electrode electrode ear portion 232b, a weakening structure 23331 is provided on the negative electrode electrode ear 2333b close to the side indicated by the left arrow M in Figure 7, and in the stacking direction of multiple negative electrode electrode ears 2333b (refer to the direction of arrow Y in Figure 7), the first negative electrode electrode ear 2333b, the second negative electrode electrode ear 2333b, and the two last negative electrode electrode ears 2333b are provided with a weakening structure 23331. In another embodiment, in combination with Figures 14, 15 and 16, when the pole ear portion 232 is a negative pole ear portion 232b, a weakening structure 23331 is provided on the negative pole ear 2333b close to the side indicated by the arrow M in Figure 15, and in the stacking direction of multiple negative pole ears 2333b (refer to the direction of arrow Y in Figure 15), the first negative pole ear 2333b and the last negative pole ear 2333b are provided with a weakening structure 23331.

[0118] In the related art, after the ends of the multiple pole lugs 2333 facing away from the main body 231 are folded in the stacking direction of the multiple pole lugs 2333, the folded position of the pole lug portion 232 can be close to the first pole lug 2333, or close to the last pole lug 2333, or can be located in the middle position of the pole lug portion 232 in the stacking direction of the pole lugs 2333; when the folded position of the pole lug portion 232 is close to the first pole lug 2333, the last pole lug 2333 and some pole lugs 2333 close to the last pole lug 2333 have large bending deformation and large stress, therefore, the last pole lug 2333 and some pole lugs 2333 close to the last pole lug 2333 can be provided with a weakening structure 23331, thereby effectively reducing the cracking and fragmentation of the pole lug 2333.

[0119] When the folded position of the pole ear portion 232 is close to the last pole ear 2333, the first pole ear 2333 and some pole ears 2333 close to the first pole ear 2333 are greatly deformed and have great stress. Therefore, the first pole ear 2333 and some pole ears 2333 close to the first pole ear 2333 can be provided with a weakening structure 23331, thereby effectively reducing the cracking and fragmentation of the pole ear 2333.

[0120] The folded position of the pole ear portion 232 is located in the middle position of the pole ear portion 232 along the stacking direction of the pole ears 2333, so that the pole ears 2333 located on both sides of the folded position have large bending deformation and large stress, that is, the first pole ear 2333 and some pole ears 2333 close to the first pole ear 2333 have large bending deformation and large stress, and the last pole ear 2333 and some pole ears 2333 close to the last pole ear 2333 have large bending deformation and large stress; in other words, after the pole ears 2333 are folded, the pole ears 2333 close to the outside of the pole ear portion 232 have large bending deformation and large stress; therefore, the last pole ear 2333, some pole ears 2333 close to the last pole ear 2333, the first pole ear 2333 and some pole ears 2333 close to the first pole ear 2333 can be provided with a weakening structure 23331, thereby effectively reducing the cracking and fragmentation of the pole ears 2333.

[0121] By adopting the technical solution of this embodiment, after the multiple pole ears 2333 are folded together, the pole ears 2333 close to the outside of the pole ear portion 232 have a large bending deformation and high stress, and the pole ears 2333 close to the outside of the pole ear portion 232 are provided with a weakening structure 23331, which can effectively reduce the stress of the pole ears 2333 close to the outside of the pole ear portion 232 and effectively improve the cracking and fragmentation of the pole ears 2333.

[0122] In another embodiment of the present application, as shown in FIG7 , the number of the tabs 2333 provided with the weakening structure 23331 is N1, and the total number of the tabs 2333 is N2, wherein 0<N1 / N2≤0.2.

[0123] In actual applications, in the positive electrode ear portion 232a, the total number of positive electrode ears 2333a is N2, and the number of positive electrode ears 2333a provided with weakening structures 23331 is N1; in the negative electrode ear portion 232b, the total number of negative electrode ears 2333b is N2, and the number of negative electrode ears 2333b provided with weakening structures 23331 is N1.

[0124] By adopting the technical solution of this embodiment, the design of 0<N1 / N2≤0.2 makes it possible that when the total number of pole ears 2333 is constant, the proportion of pole ears 2333 provided with weakening structures 23331 is small, that is, the number of pole ears 2333 provided with weakening structures 23331 in the pole ears 2333 is small, which can facilitate the production of the pole piece 233.

[0125] In another embodiment of the present application, as shown in FIG7 , 0.05≤N1 / N2≤0.1.

[0126] By adopting the technical solution of this embodiment, the design of 0.05≤N1 / N2≤0.1 makes it possible that when the total number of pole tabs 2333 is certain, the proportion of pole tabs 2333 provided with weakening structures 23331 is reasonable, that is, the number of pole tabs 2333 provided with weakening structures 23331 in the pole tabs 2333 is reasonable, which can effectively alleviate the cracking and debris of the pole tabs 2333, and the production of the pole piece 233 is also simpler and faster.

[0127] In one embodiment, the value of N1 / N2 may be, but is not limited to, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, or 0.2.

[0128] In another embodiment of the present application, as shown in combination with FIG. 7 and FIG. 8 , the number of the tabs 2333 provided with the weakening structure 23331 is N1, where 1≤N1≤20.

[0129] By adopting the technical solution of this embodiment and the design of 1≤N1≤20, the number of the pole tabs 2333 provided with the weakening structure 23331 is small, which can facilitate the production of the pole piece 233.

[0130] In another embodiment of the present application, 5≤N1≤15.

[0131] By adopting the technical solution of this embodiment, 5≤N1≤15, the number of pole tabs 2333 provided with weakening structures 23331 in the pole tabs 2333 is reasonable, which can effectively alleviate the cracking and fragmentation of the pole tabs 2333, and the production of the pole piece 233 is also simpler and faster.

[0132] In one embodiment, the value of N1 can be, but is not limited to, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20.

[0133] In one embodiment, in the electrode assembly 23, the total number N2 of the tabs 2333 in the tab portion 232 ranges from 5 to 100. Setting the number of tabs 2333 in the group of tabs 2333 within this range reduces the effort required to fold and bend the tabs 2333, and provides a suitable bending deformation of the tabs 2333 near the outer side of the tab portion 232 after folding, thereby improving the performance of the electrode assembly 23. The number of negative tabs 2333b is greater than the number of positive tabs 2333a, which is beneficial for improving the performance of the electrode assembly 23. Specifically, the value of N2 can be, but is not limited to, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100.

[0134] In another embodiment of the present application, as shown in Figures 5, 7, 8 and 9, the weakened structure 23331 includes at least one of a hollow structure or a thinned structure.

[0135] The hollow structure may refer to a structure formed by removing part of the material from the portion of the tab 2333 close to the main body 231 , and the structure passes through the tab 2333 .

[0136] The thinned structure may mean that the thickness of the tab 2333 at the thinned structure is smaller than the thickness at other positions, thereby achieving the effect of reducing the structural strength.

[0137] The weakening structure 23331 includes a hollow structure, and the weakening structure 23331 is simple and easy to process; the weakening structure 23331 includes a thinning structure, and the weakening structure 23331 is simple and easy to process; the weakening structure 23331 includes a hollow structure and a thinning structure, and the weakening structure 23331 can be flexibly set with a hollow structure and a thinning structure according to the bending characteristics of the tab 2333 to achieve a better effect of reducing stress and better improve the cracking and debris of the tab 2333.

[0138] By adopting the technical solution of this embodiment, the weakening structure 23331 has a variety of structures to be applicable to different types of tabs 2333 , so as to better improve the cracking and chipping of the tabs 2333 .

[0139] In another embodiment of the present application, in combination with Figures 5, 7, 8 and 9, when the weakened structure 23331 includes a hollow structure, the hollow structure is a through hole.

[0140] The through hole may refer to a through hole structure provided in the portion of the tab 2333 close to the main body 231. For example, the through hole passes through the tab 2333 in the thickness direction of the tab 2333. The number of through holes may be multiple, and the shape of the through holes may be various, such as circular, polygonal, elliptical, etc.

[0141] By adopting the technical solution of this embodiment, the hollow structure adopts a through-hole structure, which can effectively reduce the structural strength of the tab 2333, reduce the stress generated by the bending of the tab 2333, and effectively improve the cracking and debris of the tab 2333; in addition, the through-hole structure is simple and easy to process and manufacture.

[0142] In another embodiment of the present application, as shown in FIG5 , the through hole includes at least one of an elongated hole, a wavy hole, a circular hole or a polygonal hole.

[0143] The through hole may include any one of an elongated hole, a wavy hole, a circular hole and a polygonal hole; or, the through hole includes any two or any three of an elongated hole, a wavy hole, a circular hole and a polygonal hole, or, the through hole includes an elongated hole, a wavy hole, a circular hole and a polygonal hole.

[0144] In the case where the through hole includes a long strip hole, even if the pole lug 2333 cracks, the pole lug 2333 can also crack along the length direction of the long strip hole to achieve directional cracking of the pole lug 2333, and improve the irregular cracking and debris of the pole lug 2333; in the case where the through hole includes a wavy hole, even if the pole lug 2333 cracks, the pole lug 2333 also cracks along the wave extension direction of the wavy hole to achieve directional cracking of the pole lug 2333, and improve the irregular cracking and debris of the pole lug 2333; in the case where the through hole includes a circular hole, the circular hole structure is simple and convenient to process; in the case where the through hole includes a polygonal hole, even if the pole lug 2333 cracks, the pole lug 2333 can also crack at the corner of the polygonal hole to guide the cracking direction of the pole lug 2333, and improve the irregular cracking and debris of the pole lug 2333.

[0145] By adopting the technical solution of this embodiment, the shape of the through hole is more regular, which is convenient for processing and manufacturing.

[0146] In one embodiment, as shown in FIG10 , the height H2 of the tab 2333 ranges from 2 mm to 50 mm. When the height H2 of the tab 2333 is within this range, the tab 2333 has an appropriate height, and the multiple tabs 2333 have an appropriate welding area and good welding strength, which helps improve the reliability of the battery cell 20. Furthermore, redundancy can be reduced, which helps improve the energy density of the battery cell 20. The value of H2 can be, but is not limited to, 2 mm, 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, or 50 mm.

[0147] In another embodiment of the present application, as shown in Figures 7 to 12, the distance between the weakened structure 23331 and the active material 2332 of the electrode assembly 23 is L, where 5 mm ≤ L ≤ 25 mm.

[0148] The active material 2332 of the electrode assembly 23 may refer to the active material 2332 coated on the electrode piece 233: for example, before the electrode piece 233 is wound, in combination with Figures 10 to 12, the area below the dotted line is the area on the electrode piece 233 where the active material 2332 is coated, and the distance L between the weakening structure 23331 and the active material 2332 of the electrode assembly 23 may refer to the distance between the weakening structure 23331 and the dotted line.

[0149] By adopting the technical solution of this embodiment, the setting of 5mm≤L≤25mm allows a certain distance to exist between the weakened structure 23331 and the active material 2332, which can reduce the risk of the tab 2333 cracking to the active material 2332 coating area, which is beneficial to improving the reliability of the battery cell 20; in addition, a certain distance can be created between the weakened structure 23331 and the welding area of ​​the tab 2333, which has good welding strength and is also beneficial to alleviating the cracking and debris of the tab 2333, thereby improving the performance of the battery cell 20.

[0150] In another embodiment of the present application, as shown in Figures 7 to 12, 10 mm ≤ L ≤ 20 mm.

[0151] By adopting the technical solution of this embodiment, the setting of 10mm≤L≤20mm allows a reasonable distance between the weakened structure 23331 and the active material 2332, which effectively reduces the risk of the tab 2333 cracking to the active material 2332 coating area, and effectively improves the reliability of the battery cell 20; in addition, the spacing between the weakened structure 23331 and the welding area of ​​the tab 2333 can be set more reasonably, which is conducive to improving the welding strength, and can also effectively alleviate the cracking and debris of the tab 2333, thereby improving the performance of the battery cell 20.

[0152] In one embodiment, the value of L may be, but is not limited to, 5 mm, 7 mm, 9 mm, 10 mm, 12 mm, 14 mm, 15 mm, 16 mm, 18 mm, 20 mm, 22 mm, 24 mm, or 25 mm.

[0153] In another embodiment of the present application, as shown in Figures 10 to 12, the weakening structure 23331 is in the shape of an elongated strip.

[0154] In other words, the weakening structure 23331 is a long strip-shaped weakening structure 23331; for example, the weakening structure 23331 is a structure such as a long strip hole or a long strip groove.

[0155] By adopting the technical solution of this embodiment, the weakening structure 23331 is in the shape of an elongated strip. During the stress release process, the tab 2333 will crack along the length direction of the elongated weakening structure 23331, thereby realizing directional cracking of the tab 2333 and improving the irregular cracking and debris conditions. In this way, in actual application, the length direction of the weakening structure 23331 can be controlled to reduce the risk of the tab 2333 being torn to the active material 2332 coating area, thereby reducing the risk of the active material 2332 falling, which is beneficial to improving the reliability of the battery cell 20.

[0156] In another embodiment of the present application, as shown in FIG12 , the weakening structure 23331 and the end surface of the main body 231 form a preset angle, and the preset angle is A, where 0°≤A≤30°.

[0157] The end surface of the main body 231 may refer to a plane formed by winding the edge of the current collector 2331 (see the edge indicated by arrow T1 in FIG12 ). For example, the end surface of the main body 231 may refer to the surface indicated by arrow G in FIG5 .

[0158] The weakening structure 23331 forms a preset angle with the end face of the main body 231. It can be understood that before the pole piece 233 is wound, the angle formed between the center line of the weakening structure 23331 (see line K in Figure 10) and the edge of the current collector 2331 is the preset angle A.

[0159] By adopting the technical solution of this embodiment, the design of 0°≤A≤30° makes the inclination angle of the length direction of the weakening structure 23331 relative to the edge of the current collector 2331 smaller, so that the tab 2333 is not likely to crack along the length direction of the weakening structure 23331 and is not likely to crack to the active material 2332 coating area, thereby reducing the risk of the active material 2332 falling off the current collector 2331, which is beneficial to improving the reliability of the battery cell 20.

[0160] In another embodiment of the present application, as shown in FIG12 , 0°≤A≤10°.

[0161] By adopting the technical solution of this embodiment, the design of 0°≤A≤30° makes the inclination angle of the length direction of the weakening structure 23331 relative to the edge of the current collector 2331 smaller, so that the tab 2333 is less likely to crack along the length direction of the weakening structure 23331 and is less likely to crack to the active material 2332 coating area, which can effectively reduce the risk of the active material 2332 falling off the current collector 2331 and effectively alleviate the debris situation.

[0162] In one embodiment, the value of A can be, but is not limited to, 0°, 2°, 4°, 6°, 8°, 10°, 12°, 14°, 16°, 18°, 20°, 22°, 24°, 26°, 28°, or 30°.

[0163] In another embodiment of the present application, as shown in conjunction with Figures 10 to 12 , the weakening structure 23331 is located between two opposite sides of the tab 2333 in the width direction.

[0164] The weakening structure 23331 is located between two opposite sides of the tab 2333 in the width direction. It is understood that the weakening structure 23331 does not penetrate the side of the tab 2333 in the width direction of the tab 2333. That is, there is more material at both ends of the tab 2333 at the weakening structure 23331. This material connects the portions of the tab 2333 located on opposite sides of the weakening structure 23331 to increase the structural strength of the tab 2333 at both ends of the weakening structure 23331. For example, the two opposite sides of the tab 2333 in the width direction may refer to the two side edges of the tab 2333 distributed along the width direction of the tab 2333. Specifically, refer to the two sides indicated by arrows T2 in FIG. 7 .

[0165] By adopting the technical solution of this embodiment, the structural strength of the tab 2333 at both ends of the weakened structure 23331 is good, which can reduce the risk of the tab 2333 breaking from the weakened structure 23331.

[0166] In another embodiment of the present application, as shown in Figures 10 to 12, in the width direction of the tab 2333, the size of the weakening structure 23331 is W1, and the maximum size of the tab 2333 is W2, wherein 0<W1 / W2≤0.8.

[0167] In the width direction of the pole lug 2333, the size of the weakening structure 23331 is W1. It can be understood that the projection size of the weakening structure 23331 in the width direction of the pole lug 2333 is W1. For example, when the length direction of the weakening structure 23331 is parallel to the width direction of the pole lug 2333, the length of the weakening structure 23331 is W1.

[0168] In the width direction of the pole lug 2333, the maximum dimension of the pole lug 2333 is W2. It can be understood that the maximum width of the pole lug 2333 is W2, wherein it can be understood that when the width of the pole lug 2333 does not change in the height direction of the pole lug 2333, the maximum width of the pole lug 2333 is equal to the width at any position of the pole lug 2333.

[0169] By adopting the technical solution of this embodiment, with a design of 0 < W1 / W2 ≤ 0.8, the weakening structure 23331 can reduce the structural strength of the portion of the tab 2333 near the main body 231, reducing the risk of tab 2333 cracking due to stress release. At the same time, the tab 2333 also has a certain structural strength at the weakening structure 23331, reducing the risk of tab 2333 fracturing at the weakening structure 23331. Furthermore, the tab portion 232 has a large cross-sectional area at the weakening structure 23331, providing good current flow capacity and meeting the requirements of rapid charging and discharging.

[0170] In another embodiment of the present application, as shown in conjunction with Figures 10 to 12, 0<W1 / W2≤0.5.

[0171] By adopting the technical solution of this embodiment, with a design of 0<W1 / W2≤0.5, the proportion of the weakening structure 23331 in the width direction of the tab 2333 is more reasonable, allowing the weakening structure 23331 to reduce the structural strength of the portion of the tab 2333 near the main body 231, thereby reducing the risk of the tab 2333 cracking due to stress release. The tab 2333 also has reasonable structural strength at the weakening structure 23331, effectively reducing the risk of the tab 2333 breaking at the weakening structure 23331. In addition, the cross-sectional area of ​​the tab portion 232 at the weakening structure 23331 is also larger, and the tab portion 232 has good current capacity, which can better meet the requirements of rapid charging and discharging.

[0172] In one embodiment, the value of W1 / W2 may be, but is not limited to, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7 or 0.8.

[0173] In another embodiment of the present application, as shown in Figures 10 to 12 , in the width direction of the tab 2333 , the size of the weakening structure 23331 is W1, 4mm≤W1≤80mm.

[0174] By adopting the technical solution of this embodiment, the design of 4mm≤W1≤80mm, the size of the weakening structure 23331 in the width direction of the pole ear 2333 is reasonably set, so that the weakening structure 23331 can reduce the structural strength of the part of the pole ear 2333 close to the main body 231, and reduce the cracking of the pole ear 2333 due to stress release. At the same time, the pole ear 2333 also has a certain structural strength at the weakening structure 23331, reducing the risk of the pole ear 2333 breaking at the weakening structure 23331; in addition, the cross-sectional area of ​​the pole ear portion 232 at the weakening structure 23331 is large, and the pole ear portion 232 has good current flow capacity, which can meet the requirements of fast charging and discharging.

[0175] In another embodiment of the present application, as shown in Figures 10 to 12 , 10 mm ≤ W1 ≤ 50 mm.

[0176] By adopting the technical solution of this embodiment, the design of 10mm≤W1≤50mm, the size setting of the weakening structure 23331 in the width direction of the pole ear 2333 is more reasonable, so that the weakening structure 23331 can reduce the structural strength of the part of the pole ear 2333 close to the main body 231, and reduce the cracking of the pole ear 2333 due to stress release. At the same time, the pole ear 2333 also has a more reasonable structural strength at the weakening structure 23331, thereby effectively reducing the risk of the pole ear 2333 breaking at the weakening structure 23331; in addition, the cross-sectional area of ​​the pole ear portion 232 at the weakening structure 23331 is also larger, and the pole ear portion 232 has a good current flow capacity, which can better meet the requirements of fast charging and discharging.

[0177] In one embodiment, the value of W1 may be, but is not limited to, 4mm, 8mm, 10mm, 12mm, 16mm, 20mm, 24mm, 28mm, 32mm, 36mm, 40mm, 44mm, 48mm, 50mm, 52mm, 56mm, 60mm, 64mm, 68mm, 72mm, 76mm, or 80mm.

[0178] In one embodiment, the maximum width W2 of the tab 2333 ranges from 5 mm to 100 mm. Setting the maximum width W2 of the tab 2333 within this range allows the tab portion 232 to have a larger cross-sectional area when collapsed, thereby improving current flow capacity. Furthermore, when the tab portion 232 faces the end cap 21, interference between the tab 2333 and the end cap 21 is reduced, and functional areas such as welding areas and explosion-proof areas on the end cap 21 are shielded, thereby improving the performance of the battery cell 20. The value of W2 can be, but is not limited to, 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, 55 mm, 60 mm, 65 mm, 70 mm, 75 mm, 80 mm, 85 mm, 90 mm, 95 mm, or 100 mm.

[0179] In another embodiment of the present application, as shown in Figures 10 to 12, in the height direction of the tab 2333, the size of the weakening structure 23331 is H1, and the size of the tab 2333 is H2, wherein 0

[0180] In the height direction of the tab 2333 , the size of the weakening structure 23331 is H1 . It can be understood that the projection size of the weakening structure 23331 in the height direction of the tab 2333 is H1 .

[0181] In the height direction of the tab 2333 , the dimension of the tab 2333 is H2 . It can be understood that the height of the tab 2333 is H2 .

[0182] ​By adopting the technical solution of this embodiment, the design of 0

[0183] In another embodiment of the present application, 0.01

[0184] By adopting the technical solution of this embodiment, the design of 0.01

[0185] In one embodiment, the value of H1 / H2 may be, but is not limited to, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09 or 0.1.

[0186] The following describes the method in conjunction with some embodiments.

[0187] In one specific embodiment, the positive electrode tab 233a, the negative electrode tab 233b, and the separator 234 in the electrode assembly 23 are wound together, with the positive electrode tab 232a and the negative electrode tab 232b extending from opposite sides of the electrode assembly 23. The thickness of the electrode assembly 23 is 10 mm, the number of positive electrode tabs 2333a is 60, and the number of negative electrode tabs 2333b is 66. The thickness of the positive electrode tab 2333a is 13 μm, the thickness of the negative electrode tab 2333b is 6 μm, the height of the positive electrode tab 2333a and the height of the negative electrode tab 2333b are 15 mm, and the height of the positive electrode tab 2333a and the height of the negative electrode tab 2333b are 40 mm. The weakening structure 23331 is a long through hole with a height of 2 mm and a length of 25 mm. The number of positive electrode tabs 2333a provided with the long through hole is 6, and the number of negative electrode tabs 2333b provided with the long through hole is 7. Comparing the electrode assembly 23 of this embodiment with an electrode assembly 23 without the tabs 2333 provided with the long through hole, the opening design significantly reduces the pulling of the tabs 2333 by the stress release of the outer layer, thereby improving the problem of irregular cracking and chipping of the tabs 2333. ​​​

[0188] In another specific embodiment, the positive electrode tab 233a, the negative electrode tab 233b, and the separator 234 in the electrode assembly 23 are wound together, and the positive electrode tab 232a and the negative electrode tab 232b are extended from the same side of the electrode assembly 23. The thickness of the electrode assembly 23 is 12 mm, the number of positive electrode tabs 2333a is 60, and the number of negative electrode tabs 2333b is 66. The thickness of the positive electrode tab 2333a is 13 μm, the thickness of the negative electrode tab 2333b is 6 μm, the height of the positive electrode tab 2333a and the height of the negative electrode tab 2333b are 15 mm, and the height of the positive electrode tab 2333a and the height of the negative electrode tab 2333b are 40 mm. The weakening structure 23331 is a long through hole with a height of 2 mm and a length of 25 mm. The number of positive electrode tabs 2333a provided with the long through hole is 6, and the number of negative electrode tabs 2333b provided with the long through hole is 7.

[0189] In another embodiment of the present application, a battery cell 20 is provided, comprising the electrode assembly 23 according to the above embodiment.

[0190] In another embodiment of the present application, a battery 1100 is provided, comprising the battery cell 20 according to the above embodiment.

[0191] In another embodiment of the present application, an electrical device is provided, comprising the battery 1100 according to the above embodiment.

[0192] The above description of the various embodiments tends to emphasize the differences between the various embodiments. The same or similar aspects can be referenced with each other and will not be repeated herein for the sake of brevity.

[0193] 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. An electrode assembly, characterized in that: include: A main body, a plurality of tabs extending from the end of the main body, the plurality of tabs being stacked; Wherein, a portion of at least one of the pole lugs close to the main body is provided with a weakening structure, and the weakening structure is used to reduce the structural strength of the portion of the pole lug close to the main body.

2. The electrode assembly according to claim 1, characterized in that: The plurality of stacked pole tabs form a pole tab portion; in the stacking direction of the plurality of pole tabs, at least the pole tab close to the outer side of the pole tab portion is provided with the weakening structure.

3. The electrode assembly according to claim 1 or 2, characterized in that: The number of the pole tabs provided with the weakening structure is N1, and the total number of the pole tabs is N2, wherein 0<N1 / N2≤0.

2.

4. The electrode assembly according to claim 3, characterized in that: 0.05≤N1 / N2≤0.

1.

5. The electrode assembly according to any one of claims 1 to 4, characterized in that: The number of the tabs provided with the weakening structure is N1, wherein 1≤N1≤20.

6. The electrode assembly according to claim 5, characterized in that: 5≤N1≤15。 7. The electrode assembly according to any one of claims 1 to 6, characterized in that: The weakened structure includes at least one of a hollow structure and a thinned structure.

8. The electrode assembly according to claim 7, characterized in that: In the case where the weakened structure includes a hollow structure, the hollow structure is a through hole.

9. The electrode assembly according to claim 8, characterized in that: The through hole includes at least one of an elongated hole, a wavy hole, a circular hole or a polygonal hole.

10. The electrode assembly according to any one of claims 1 to 9, characterized in that: The distance between the weakened structure and the active material of the electrode assembly is L, wherein 5 mm ≤ L ≤ 25 mm.

11. The electrode assembly according to claim 10, characterized in that: 10mm≤L≤20mm.

12. The electrode assembly according to any one of claims 1 to 11, characterized in that: The weakened structure is in the shape of a long strip.

13. The electrode assembly according to claim 12, characterized in that: The weakening structure and the end surface of the main body form a preset angle, and the preset angle is A, wherein 0°≤A≤30°.

14. The electrode assembly according to claim 13, characterized in that: 0°≤A≤10°。 15. The electrode assembly according to any one of claims 1 to 14, characterized in that: The weakened structure is located between two opposite sides of the tab in the width direction.

16. The electrode assembly according to any one of claims 1 to 15, characterized in that: In the width direction of the pole lug, the dimension of the weakened structure is W1, and the maximum dimension of the pole lug is W2, wherein 0<W1 / W2≤0.

8.

17. The electrode assembly according to claim 16, characterized in that: 0<W1 / W2≤0.

5.

18. The electrode assembly according to any one of claims 1 to 17, characterized in that: In the width direction of the pole ear, the size of the weakened structure is W1, 4mm≤W1≤80mm.

19. The electrode assembly according to claim 18, characterized in that: 10mm≤W1≤50mm.

20. The electrode assembly according to any one of claims 1 to 19, characterized in that: In the height direction of the pole lug, the size of the weakened structure is H1, and the size of the pole lug is H2, wherein 0<H1 / H2≤0.

1.

21. The electrode assembly according to claim 20, characterized in that: 0.01<H1 / H2≤0.

05.

22. A battery cell, characterized in that: An electrode assembly comprising any one of claims 1 to 21.

23. A battery, characterized in that: Comprising the battery cell as claimed in claim 22.

24. An electrical device, characterized in that: Comprising the battery of claim 23.

Images