Battery monomer, battery and electric device

Abstract

The utility model provides a battery monomer, a battery and a power utilization device. The battery monomer comprises a shell, an electrode assembly and a first current collector, and the shell comprises a first electrode lead-out part; the electrode assembly is contained in the shell and comprises a first electrode piece wound in the winding direction, a first electrode lug is arranged at the end, facing the first electrode leading-out part, of the first electrode piece, and the first electrode lug is wound in the winding direction and comprises multiple circles of first electrode lug layers. The first current collecting piece is connected between the first electrode leading-out part and the first tab, the first current collecting piece comprises a first connecting part used for connecting the first tab, and the first connecting part is at least partially overlapped with each circle of first tab layer in the direction parallel to the winding axis of the first pole piece. According to the invention, the reliability of the battery monomer can be effectively improved.

Description

Technical Field

[0001] The present application relates to the technical field of batteries, and particularly to a battery cell, a battery and an electrical device. Background Art

[0002] Battery cells 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 and electric tools, etc. Battery cells can include nickel-cadmium battery cells, nickel-metal hydride battery cells, lithium-ion battery cells, secondary alkaline zinc-manganese battery cells, etc.

[0003] In the development of battery technology, the reliability of battery cells will directly affect the reliability, usage cost and user experience of terminal products. Therefore, how to effectively improve the reliability of battery cells is an urgent technical problem in battery technology. Summary of the Utility Model

[0004] In view of the above problems, the present application provides a battery cell, a battery and an electrical device, which can effectively improve the reliability of the battery cell.

[0005] In a first aspect, an embodiment of the present application provides a battery cell. The battery cell includes a housing, an electrode assembly and a first current collector. The housing includes a first electrode lead-out portion. The electrode assembly is accommodated in the housing. The electrode assembly includes a first electrode tab wound along a winding direction. The first electrode tab is provided with a first tab at one end facing the first electrode lead-out portion. The first tab is wound along the winding direction and includes multiple layers of first tab layers. The first current collector is connected between the first electrode lead-out portion and the first tab. The first current collector includes a first connection portion for connecting the first tab. In a direction parallel to the winding axis of the first electrode tab, the first connection portion at least partially overlaps with each layer of the first tab layers.

[0006] The above technical solution can enable the first connection portion of the first current collector to cover each layer of the first tab layers, so that the first current collector can be directly connected to each layer of the first tab layers, including the outermost layer of the first tab layers. Furthermore, each layer of the first tab layers can directly form a current flow with the current collector, reducing the conduction path between the current collector and each layer of the first tab layers, so as to improve the over-current capacity of the battery cell and reduce the risk of lithium deposition in the battery cell, thereby effectively improving the reliability of the battery cell.

[0007] In some embodiments of the first aspect, multiple layers of the first tab layers converge in a direction close to the winding axis.

[0008] The above technical solution can increase the range of the outermost layer of the first tab layers extending inwards, thereby further reducing the connection difficulty between the outermost layer of the first tab layers and the first current collector.

[0009] In some embodiments of the first aspect, the size of the multi-turn first tab layer gradually increases from the inside to the outside in the direction parallel to the winding axis.

[0010] In the above technical solution, the size of the first tab layer closer to the outer circle in the direction parallel to the winding axis is larger, which can further reduce the connection difficulty between the first tab layer closer to the outer circle and the first current collector.

[0011] In some embodiments of the first aspect, the first tab includes a first part and a second part. The first part is connected to one end of the second part in the winding direction, and the first part surrounds the outer periphery of the second part. The first dimension of the first part in the direction parallel to the winding axis is greater than the second dimension of the second part in the direction parallel to the winding axis.

[0012] In the above technical solution, by setting the first tab as the first part and the second part with different sizes in the direction parallel to the winding axis, and the first dimension of the first part in the direction parallel to the winding axis is greater than the second dimension of the second part in the direction parallel to the winding axis, it is possible to further reduce the connection difficulty between the first tab layer closer to the outer circle and the first current collector while reducing the overall preparation difficulty of the electrode assembly, which is beneficial to reducing the overall cost of the battery cell.

[0013] In some embodiments of the first aspect, the first tab further includes a third part, and the third part is connected between the first part and the second part. In the winding direction, the third dimension of the third part in the direction parallel to the winding axis gradually increases.

[0014] In the above technical solution, by introducing the third part, in the winding direction, the third dimension of the third part in the direction parallel to the winding axis gradually increases. The third part can form a transition between the first part and the second part, reducing the impact of the size mutation between the first part and the second part on the overall structural stability of the first tab, and effectively improving the overall reliability of the battery cell.

[0015] In some embodiments of the first aspect, the first current collector further includes a first main body portion, and the first connecting portion is connected to the first main body portion. The first connecting portion includes a first convex portion, and the first convex portion protrudes from the surface of the first main body portion facing the first tab and abuts against the first tab.

[0016] The first convex portion presses against the first tab. In this way, when welding the first convex portion and the first tab, the risk of false welding can be reduced, and the connection strength between the first convex portion and the first tab can be improved.

[0017] In some embodiments of the first aspect, the first connecting portion further includes a first concave portion corresponding to the first convex portion, and the first concave portion is recessed relative to the surface of the first main body portion facing away from the first tab.

[0018] By providing the first recess, the first recess can accommodate metal particles to reduce the risk of metal particles falling into the electrode assembly. Additionally, the first recess can also reduce the space occupied by the first current collector in the direction parallel to the winding axis.

[0019] In some embodiments of the first aspect, the housing further includes a second electrode lead-out portion. The electrode assembly further includes a second electrode tab wound along the winding direction, the second electrode tab having a polarity opposite to that of the first electrode tab. The second electrode tab is provided with a second tab at one end facing the second electrode lead-out portion. The second tab is wound along the winding direction and includes multiple layers of the second tab layer. The battery cell further includes a second current collector connected between the second electrode lead-out portion and the second tab. The second current collector includes a second connection portion for connecting to the second tab. In the direction parallel to the winding axis, the second connection portion at least partially overlaps with each layer of the second tab layer.

[0020] The above technical solution enables the second connection portion of the second current collector to cover each layer of the second tab layer, allowing the second current collector to be directly connected to each layer of the second tab layer, including the outermost layer of the second tab layer. Consequently, each layer of the second tab layer can directly form a current path with the current collector, reducing the conduction path between the current collector and each layer of the second tab layer, thereby further improving the current-carrying capacity of the battery cell, further reducing the risk of lithium plating in the battery cell, and thus further enhancing the reliability of the battery cell.

[0021] In some embodiments of the first aspect, the first electrode lead-out portion and the second electrode lead-out portion are disposed opposite to each other in the direction parallel to the winding axis.

[0022] The above technical solution reduces the difficulty of arranging the first electrode lead-out portion and the second electrode lead-out portion, as well as reduces the risk of short circuit in the battery cell.

[0023] In some embodiments of the first aspect, the battery cell further includes a first adapter connected between the first current collector and the first electrode lead-out portion.

[0024] The above technical solution can reduce the connection difficulty between the first current collector and the first electrode lead-out portion by introducing the first adapter, thereby facilitating the improvement of the product yield of the battery cell.

[0025] In some embodiments of the first aspect, the first adapter is provided with reinforcing ribs.

[0026] The above technical solution can effectively improve the structural strength of the first adapter and reduce the risk of fracture by providing reinforcing ribs on the first adapter, thereby effectively enhancing the overall reliability of the battery cell.

[0027] In some embodiments of the first aspect, the battery cell is a cylindrical battery cell.

[0028] In a second aspect, the present application provides a battery, which includes the battery cell provided in any of the embodiments of the first aspect.

[0029] In a third aspect, the present application provides an electrical device, which includes the battery cell provided in any of the embodiments of the first aspect, and the battery cell is used to provide electrical energy.

[0030] The above description is only an overview of the technical solution of the present application. In order to be able to understand the technical means of the present application more clearly, 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 describes the specific embodiments of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present application. Moreover, throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0032] Figure 1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0033] Figure 2 is an exploded structural diagram of a battery provided in some embodiments of the present application;

[0034] Figure 3 is a three-dimensional structural diagram of a battery cell provided in some embodiments of the present application;

[0035] Figure 4 is an exploded structural diagram of a battery cell provided in some embodiments of the present application;

[0036] Figure 5 is a three-dimensional structural diagram of a first current collector of a battery cell provided in some embodiments of the present application;

[0037] Figure 6 is a top view structural diagram of the cooperation between an electrode assembly and a first current collector of a battery cell provided in some embodiments of the present application;

[0038] Figure 7 is a three-dimensional structural diagram of an electrode assembly after the first tab and the second tab are flattened provided in some embodiments of the present application;

[0039] Figure 8 is Figure 7 a schematic cross-sectional structure diagram along A-A;

[0040] Figure 9 Schematic three-dimensional structure diagram of an electrode assembly provided by some embodiments of the present application after the first tab and the second tab are folded together;

[0041] Figure 10 is Figure 9 Schematic cross-sectional structure diagram along B-B;

[0042] Figure 11 Schematic structure diagram of a first pole piece provided by some embodiments of the present application;

[0043] Figure 12 Schematic structure diagram of another first pole piece provided by some embodiments of the present application.

[0044] Reference numerals in the drawings in the specific embodiments are as follows:

[0045] 1. Vehicle; 2. Battery; 3. Controller; 4. Motor; 5. Box body; 6. Battery cell;

[0046] 10. Outer shell; 11. First electrode lead-out part; 12. Second electrode lead-out part;

[0047] 20. Electrode assembly; 21. First pole piece; 211. First tab; 2111. First tab layer; 2112. First part; 2113. Second part; 2114. Third part; 221. Second tab; 2211. Second tab layer;

[0048] 30. First current collector; 31. First connection part; 311. First convex part; 312. First concave part; 32. First main body part;

[0049] 40. First adapter; 41. Reinforcing rib;

[0050] X. Winding direction; K. Winding axis; d1. First dimension; d2. Second dimension; d3. Third dimension. Specific embodiments

[0051] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Apparently, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0052] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by those skilled in the technical field to which this application belongs; the terms used in the specification of this application 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, claims and above-mentioned drawings of this application are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the specification, claims or above-mentioned drawings of this application are used to distinguish different objects and not to describe a specific order or primary-secondary relationship.

[0053] Reference to "embodiment" in this application means that a specific feature, structure or characteristic described in connection with the embodiment can be included in at least one embodiment of this application. The phrase appearing at various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments.

[0054] In the description of this application, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", "connected to", "attached to" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0055] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally represents an "or" relationship between the associated objects before and after.

[0056] In the embodiments of this 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 and other dimensions of various components in the embodiments of this application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only for illustrative purposes and should not constitute any limitation to this application.

[0057] The term "a plurality of" as used in this application means two or more (including two).

[0058] The term "parallel" in this application includes not only the case of absolute parallelism, but also the case of approximately parallelism commonly recognized in engineering; at the same time, "perpendicular" also includes not only the case of absolute perpendicularity, but also the case of approximately perpendicularity commonly recognized in engineering.

[0059] In the embodiments of the present application, the battery cell may be a secondary battery cell, which refers to a battery cell that can be activated by charging after discharging so that the active material can be reused.

[0060] The battery cell may be a lithium-ion battery cell, a sodium-ion battery cell, a sodium-lithium-ion battery cell, a lithium-metal battery cell, a sodium-metal battery cell, a lithium-sulfur battery cell, a magnesium-ion battery cell, a nickel-metal hydride battery cell, a nickel-cadmium battery cell, a lead-acid battery cell, etc., and the embodiments of the present application do not limit this.

[0061] Generally, the battery cell includes an electrode assembly. The electrode assembly includes a positive electrode and a negative electrode. During the charging and discharging process of the battery cell, active ions (such as lithium ions) are embedded and extracted back and forth between the positive electrode and the negative electrode.

[0062] In some embodiments, the electrode assembly further includes a separator, which is disposed between the positive electrode and the negative electrode, can play a role in preventing short circuit between the positive and negative electrodes, and at the same time allows active ions to pass through.

[0063] In some embodiments, the positive electrode may be a positive electrode sheet, and the positive electrode sheet may include a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector.

[0064] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector.

[0065] In some embodiments, the battery cell further includes an electrolyte, and the electrolyte plays a role in conducting ions between the positive and negative electrodes. The present application does not specifically limit the type of the electrolyte, and it can be selected according to requirements. The electrolyte may be liquid, gel or solid.

[0066] In some embodiments, the liquid electrolyte includes an electrolyte salt and a solvent.

[0067] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluoro(oxalato)borate, lithium bis(oxalato)borate, lithium difluoro(bis(oxalato))phosphate and lithium tetrafluoro(oxalato)phosphate.

[0068] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent may also be an ether solvent. The ether solvent may include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3-dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether, and crown ether.

[0069] The gel electrolyte includes a polymer as the skeleton network of the electrolyte, combined with an ionic liquid-lithium salt.

[0070] Solid electrolytes include polymer solid electrolytes, inorganic solid electrolytes, and composite solid electrolytes.

[0071] As an example, the polymer solid electrolyte may be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, single-ion polymer, polyionic liquid-lithium salt, cellulose, etc.

[0072] As an example, the inorganic solid electrolyte may be an oxide solid electrolyte (crystalline perovskite, sodium superionic conductor, garnet, amorphous LiPON film), a sulfide solid electrolyte (crystalline lithium superionic conductor (lithium germanium phosphorus sulfur, argyrodite), amorphous sulfide), and one or more of a halide solid electrolyte, a nitride solid electrolyte, and a hydride solid electrolyte.

[0073] As an example, the composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to the polymer solid electrolyte.

[0074] In some embodiments, the electrode assembly is a wound structure. The positive electrode sheet and the negative electrode sheet are wound into a wound structure.

[0075] In some embodiments, the electrode assembly is a laminated structure.

[0076] As an example, multiple positive electrode sheets and multiple negative electrode sheets may be provided respectively, and the multiple positive electrode sheets and the multiple negative electrode sheets are alternately stacked.

[0077] As an example, multiple positive electrode sheets may be provided, and the negative electrode sheet is folded to form multiple folded segments arranged in a stacked manner, and a positive electrode sheet is clamped between adjacent folded segments.

[0078] As an example, both the positive electrode sheet and the negative electrode sheet are folded to form multiple folded segments arranged in a stacked manner.

[0079] As an example, a plurality of separators may be provided and respectively disposed between any adjacent positive electrode plates or negative electrode plates.

[0080] As an example, the separators may be continuously provided and disposed between any adjacent positive electrode plates or negative electrode plates by means of folding or winding.

[0081] In some embodiments, the shape of the electrode assembly may be cylindrical, flat, prismatic, or the like.

[0082] In some embodiments, the electrode assembly is provided with tabs, and the tabs can conduct current out of the electrode assembly. The tabs include positive tabs and negative tabs.

[0083] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as the electrode assembly and the electrolyte. The housing may be a steel shell, an aluminum shell, a plastic shell (such as polypropylene), a composite metal shell (such as a copper-aluminum composite shell), or an aluminum-plastic film, etc.

[0084] As an example, the battery cell may be a cylindrical battery cell, a prismatic battery cell, a soft-pack 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.

[0085] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity.

[0086] In some embodiments, the battery may be a battery module. When there are multiple battery cells, the multiple battery cells are arranged and fixed to form a battery module.

[0087] In some embodiments, the battery may be a battery pack. The battery pack includes a box body and battery cells, and the battery cells or battery modules are accommodated in the box body.

[0088] In some embodiments, the box body may be part of the chassis structure of a vehicle. For example, a part of the box body may become at least a part of the floor of the vehicle, or a part of the box body may become at least a part of the cross beam and longitudinal beam of the vehicle.

[0089] In some embodiments, the battery may be an energy storage device. The energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0090] With the development of new energy technologies, batteries are more and more widely used, such as being applied to mobile phones, laptop computers, battery cars, electric vehicles, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and electric tools, etc.

[0091] In the development of battery technology, the reliability of a single battery cell directly affects the reliability, usage cost, and user experience of the end product.

[0092] In a single battery cell, the electrode assembly generally inputs and outputs current through tabs. Currently, in order to improve the current-carrying capacity of the tabs, the tabs are usually set as a wound structure. The wound tab includes multiple turns of tab layers, and the multiple turns of tab layers are connected end to end along the winding direction. The wound tab has a larger current-carrying area and stronger large-current resistance.

[0093] However, when the tab is connected to the current collector, there are often some tab layers that are not directly connected to the current collector, especially the tab layers located on the outer circle. The outer circle tab layers that are not directly connected to the current collector need to form current conduction through the inner circle tabs with the current collector, which results in a longer conduction path and a larger resistance between the outer circle tab layers and the current collector, reducing the current-carrying capacity of the single battery cell. When the single battery cell is charged at a high rate, lithium ions are likely to concentrate near the outer circle tab layers, generating the risk of lithium deposition, thus affecting the reliability of the single battery cell.

[0094] Based on the above considerations, the embodiments of the present application provide a single battery cell. The single battery cell includes a housing, an electrode assembly, and a first current collector. The housing includes a first electrode lead-out portion; the electrode assembly is accommodated in the housing. The electrode assembly includes a first electrode tab that is wound along the winding direction. The first electrode tab is provided with a first tab at one end facing the first electrode lead-out portion. The first tab is wound along the winding direction and includes multiple turns of first tab layers. The first current collector is connected between the first electrode lead-out portion and the first tab. The first current collector includes a first connection portion for connecting the first tab. In the direction parallel to the winding axis of the first electrode tab, the first connection portion at least partially overlaps with each turn of the first tab layers.

[0095] The above technical solution enables the first connection portion of the first current collector to cover each turn of the first tab layers, enabling the first current collector to be directly connected to each turn of the first tab layers, including the first tab layers located on the outer circle. Furthermore, each turn of the first tab layers can directly form current conduction with the current collector, reducing the conduction path between the current collector and each turn of the first tab layers, so as to improve the current-carrying capacity of the single battery cell, reduce the risk of lithium deposition in the single battery cell, and thus effectively improve the reliability of the single battery cell.

[0096] The technical solutions described in the embodiments of the present application are applicable to batteries and electrical devices using batteries.

[0097] The electrical device can be a vehicle, mobile phone, portable device, laptop, ship, spacecraft, electric toy, electric tool, etc. The vehicle can be a fuel vehicle, gas vehicle or new energy vehicle, and the new energy vehicle can be a pure electric vehicle, hybrid vehicle or range-extended vehicle, etc.; the spacecraft includes airplanes, rockets, space shuttles, spaceships, etc.; the electric toy includes fixed or mobile electric toys, such as game consoles, electric vehicle toys, electric ship toys, electric airplane toys, etc.; the electric tool includes metal cutting electric tools, grinding electric tools, assembly electric tools and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact electric drills, concrete vibrators and electric planers, etc. The embodiments of the present application do not impose special restrictions on the above electrical devices.

[0098] It should be understood that the technical solutions described in the embodiments of the present application are not only limited to the above-described battery and electrical equipment, but also applicable to all batteries including battery boxes and electrical equipment using batteries. However, for the sake of simplicity of description, the following embodiments will be described by taking an electric vehicle as an example.

[0099] Figure 1 It is a schematic structural diagram of a vehicle provided by some embodiments of the present application.

[0100] Continue to refer to Figure 1 , inside the vehicle 1, there is a battery 2, and the battery 2 can be arranged at the bottom, head or 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.

[0101] The vehicle 1 may further 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.

[0102] In some embodiments of the present application, the battery 2 can not only be used 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.

[0103] Figure 2 It is an exploded structural diagram of a battery provided by some embodiments of the present application.

[0104] Continue to refer to Figure 2 , the battery 2 includes a box body 5 and battery cells 6, and the battery cells are accommodated in the box body 5.

[0105] The box body 5 is used to accommodate the battery cells 6, and the box body 5 can be of various structures, such as a cylinder, a cuboid, etc.

[0106] In the battery 2, there can be one or more battery cells 6. If there are more than one battery cell 6, the battery cells 6 can be connected in series, in parallel or in mixed connection. Mixed connection means that the battery cells 6 are both connected in series and in parallel. The battery cells 6 can be directly connected in series, in parallel or in mixed connection, and then the whole formed by the battery cells 6 can be accommodated in the box 5; of course, the battery cells 6 can also be connected in series, in parallel or in mixed connection to form a battery module, and then the battery modules can be connected in series, in parallel or in mixed connection to form a whole, and then accommodated in the box 5.

[0107] Figure 3 A schematic diagram of a three-dimensional structure of a battery cell provided in some embodiments of the present application. Figure 4 A schematic diagram of an exploded structure of a battery cell provided in some embodiments of the present application, Figure 5 This is a schematic diagram of the three-dimensional structure of a first current collecting member of a battery cell provided in some embodiments of the present application. Figure 6 This is a schematic top view of the structure of an electrode assembly of a battery cell and a first current collector provided in some embodiments of the present application. Figure 7 A schematic diagram of a three-dimensional structure of an electrode assembly provided in some embodiments of the present application, Figure 8 for Figure 7 Schematic diagram of the cross-section structure along AA; Figure 9 This is a schematic diagram of a three-dimensional structure of an electrode assembly provided in some embodiments of the present application after the first electrode tab and the second electrode tab are folded together. Figure 10 for Figure 9 Schematic diagram of the cross-sectional structure along BB.

[0108] refer to Figures 3 to 10 The embodiment of the present application provides a battery cell 6, which includes a housing 10, an electrode assembly 20 and a first current collector 30. The housing 10 includes a first electrode lead-out portion 11; the electrode assembly 20 is accommodated in the housing 10, and the electrode assembly 20 includes a first pole sheet 21 wound along a winding direction X, and the first pole sheet 21 is provided with a first pole lug 211 at one end facing the first electrode lead-out portion 11. The first pole lug 211 is wound along the winding direction X and includes a plurality of turns of first pole lug layers 2111. The first current collector 30 is connected between the first electrode lead-out portion 11 and the first pole lug 211, and includes a first connecting portion 31 for connecting the first pole lug 211. In a direction parallel to the winding axis K of the first pole sheet 21, the first connecting portion 31 at least partially overlaps with each turn of the first pole lug layer 2111.

[0109] Exemplarily, the outer casing 10 is a component for forming the internal environment of the battery cell 6. Among them, the formed internal environment can be used to accommodate the electrode assembly 20, the electrolyte, and other components. Optionally, the outer casing 10 can be made of, but not limited to, metal or non-metal materials. For example, the metal material can be copper, aluminum, or stainless steel, etc.; the non-metal material can be polyethylene, polypropylene, or polyvinyl chloride, etc.

[0110] In some examples, the outer casing 10 can be a sealed structure or a non-sealed structure. As an example, when the outer casing 10 is a sealed structure, the outer casing 10 can play a role in protecting the electrode assembly 20 and to a certain extent prevent, such as electrolyte leakage. When the outer casing 10 is a non-sealed structure, the outer casing 10 can play a role in protecting the electrode assembly 20. A sealing bag can also be included between the outer casing 10 and the electrode assembly 20, and the sealing bag is used to encapsulate the electrode assembly 20 and the electrolyte, etc. Specifically, the sealing bag can be a bag-shaped insulating part or an aluminum-plastic film.

[0111] The battery cell 6 can also include an electrode assembly 20, and the electrode assembly 20 is accommodated in the casing. The electrode assembly 20 is a component in the battery cell 6 where an electrochemical reaction occurs. The electrode assembly 20 is mainly formed by winding or laminating a positive electrode sheet and a negative electrode sheet, and a separator is usually provided between the positive electrode sheet and the negative electrode sheet. The parts of the positive electrode sheet and the negative electrode sheet with active substances constitute the main body part of the electrode assembly 20, and the parts of the positive electrode sheet and the negative electrode sheet without active substances respectively constitute the electrode tabs. The positive electrode tab and the negative electrode tab can be located at one end of the main body part together or at both ends of the main body part respectively. During the charge and discharge process of the battery, the positive electrode active substance and the negative electrode active substance react with the electrolyte, and the electrode tabs are connected to the electrode terminals to form a current loop.

[0112] The outer casing 10 can be in various structural forms. For example, the outer casing 10 can include a housing and an end cap. The housing is a hollow structure with an opening, and the end cap is fitted over the opening of the housing and forms a sealed connection to form a sealed space for accommodating the electrode assembly 20 and the electrolyte.

[0113] The housing can be in various shapes, such as a cylinder, a cuboid, etc. The shape of the housing can be determined according to the specific shape of the electrode assembly 20. For example, if the electrode assembly 20 is a cylinder structure, a cylinder housing can be selected; if the electrode assembly 20 is a cuboid structure, a cuboid housing can be selected. Of course, the end cap can also be in various structures, such as a plate-like structure, a hollow structure, etc. Exemplarily, the housing is a cylinder structure, the end cap is a plate-like structure, and the end cap is fitted over the opening of the housing.

[0114] In some examples, the outer shell 10 includes a housing and an end cap. The housing is a hollow structure with an opening on one side, and the end cap covers the opening of the housing. In other examples, the outer shell 10 includes a housing and two end caps. The housing is a hollow structure with openings on opposite sides, and each end cap correspondingly covers one of the corresponding openings of the housing.

[0115] The end cap can be directly connected to the housing or can be connected to the housing through other components. Exemplarily, the outer shell 10 further includes a fixing member for fixing the end cap to the housing. For example, the fixing member surrounds the outside of the end cap and clamps the edge of the end cap to achieve the connection between the fixing member and the end cap; the outer edge of the fixing member is welded to the housing to achieve the connection between the fixing member and the housing.

[0116] In some examples, the outer shell 10 further includes a sealing member for sealing the opening of the housing and improving the sealing performance of the battery cell 6. Exemplarily, the sealing member can be clamped between the fixing member and the end cap.

[0117] The material of the sealing member can be polypropylene, polyethylene or fluororubber. Optionally, the sealing member is made of an insulating material, which can insulate and separate the end cap and the housing.

[0118] In some examples, the end cap is provided with an electrolyte injection hole that penetrates the end cap along the thickness direction of the end cap. During the electrolyte injection process of the battery cell 6, the electrolyte enters the interior of the battery cell 6 through the electrolyte injection hole. The battery cell 6 further includes a sealing plate connected to the end cap and covering the electrolyte injection hole for sealing the electrolyte injection hole after the electrolyte injection process is completed.

[0119] The outer shell 10 includes a first electrode lead-out portion 11 for leading out the current in the electrode assembly 20 to output the electric energy generated by the electrode assembly 20. The first electrode lead-out portion 11 can be an end cap, can be a housing, or can be other parts of the outer shell 10 as long as it can lead out the current. For example, in some examples, the end cap serves as the first electrode lead-out portion 11 and is electrically connected to the electrode assembly 20. Alternatively, the outer shell 10 further includes an electrode terminal provided on the end cap, and the electrode terminal serves as the first electrode lead-out portion 11 and is electrically connected to the electrode assembly 20.

[0120] It can be understood that the first electrode lead-out portion 11 is used to be electrically connected to other battery cells 6 through a bus bar to achieve the series or parallel connection of different battery cells 6.

[0121] The first electrode plate 21 is at least one of a positive electrode plate and a negative electrode plate. As an example, when the first electrode plate 21 is one, the first electrode plate 21 is a positive electrode plate or a negative electrode plate; when the first electrode plate 21 is two, one of the two first electrode plates 21 is a positive electrode plate and the other is a negative electrode plate.

[0122] The first pole piece 21 is wound into a whole along the winding direction X to form a winding structure. The winding structure may be a cylindrical structure, a flat structure or a structure of other shapes.

[0123] The two ends of the first pole tab 211 along the winding direction X are an inner end and an outer end respectively. In this embodiment, the first pole tab layer 2111 is divided based on the inner end of the first pole tab 211. The winding direction X is perpendicular to the winding axis K.

[0124] Specifically, the inner end of the first pole lug 211 is the head end of the first circle of the first pole lug layer 2111, the tail end of the first circle of the first pole lug layer 2111 is aligned with the head end of the first circle of the first pole lug layer 2111 in the radial direction of the first pole lug 211, and the first circle of the first pole lug layer 2111 surrounds the winding axis K. Correspondingly, the tail end of the first circle of the first pole lug layer 2111 is the head end of the second circle of the first pole lug layer 2111, and so on, multiple circles of the first pole lug layer 2111 are connected end to end along the winding direction X. When dividing the first pole lug layer 2111, the head end of each circle of the first pole lug layer 2111 is aligned with the inner end of the first pole lug 211 in the radial direction of the first pole lug 211. Among them, the radial direction of the first pole lug 211 is perpendicular to the winding axis K and passes through the winding axis K.

[0125] Exemplarily, the inner end and the outer end of the first pole tab 211 are aligned in the radial direction of the first pole tab 211 , so that each turn of the pole tab layer surrounds the winding axis K once.

[0126] Of course, alternatively, there is a portion at the tail of the first pole lug 211, which surrounds the winding axis K for less than one circle. For example, the portion can surround the winding axis K for 1 / 3, 1 / 2, 2 / 3 or 3 / 4 of a circle.

[0127] After winding is completed, the first pole lug 211 is generally cylindrical, and a gap is left between two adjacent turns of the first pole lug layer 2111. The embodiment of the present application can process the first pole lug 211 to reduce the gap between the first pole lug layers 2111, so as to facilitate the connection of the first pole lug 211 with the first current collector 30. For example, the embodiment of the present application can perform a flattening process on the first pole lug 211 so that multiple turns of the first pole lug layer 2111 are gathered and assembled together. The flattening process is to shape the first pole lug 211 by a flattening device to compact the first pole lug 211 and form a dense structure, reduce the gap between multiple turns of the first pole lug layer 2111, and facilitate the welding of the first pole lug 211 with the first current collector 30. Alternatively, the embodiment of the present application can also fill the conductive material between two adjacent turns of the first pole lug layer 2111 to reduce the gap between the pole lug layers.

[0128] The first current collector 30 is used to achieve the electrical connection between the first electrode lead-out portion 11 and the first tab 211. The first connection portion 31 is used to connect the first connection portion 31 of the first tab 211.

[0129] The first current collector 30 can be directly connected to the first electrode lead-out portion 11, or can be restricted on the first electrode lead-out portion 11 through other components. As an example, the connection method between the first current collector 30 and the first electrode lead-out portion 11 can be, but is not limited to, welding, riveting, bonding, or snap connection, etc.

[0130] The first current collector 30 can be directly connected to the first tab 211, or can be restricted on the first tab 211 through other components. As an example, the connection method between the first current collector 30 and the first tab 211 can be, but is not limited to, welding, riveting, bonding, or snap connection, etc.

[0131] The projected shape of the first connection portion 31 in the thickness direction of the first current collector 30 can be, but is not limited to, rectangular, triangular, V-shaped, W-shaped, linear, or curved, etc. Wherein, the thickness direction of the first current collector 30 is parallel to the winding axis K.

[0132] In the direction parallel to the winding axis K of the first pole piece 21, the first connection portion 31 at least partially overlaps with each turn of the first tab layer 2111. In other words, the projection of the first connection portion 31 in the direction parallel to the winding axis K of the first pole piece 21 at least partially overlaps with the projection of each turn of the first tab layer 2111 in the direction parallel to the winding axis K of the first pole piece 21. That is to say, in the direction parallel to the winding axis K of the first pole piece 21, each turn of the first tab layer 2111 overlaps with the first connection portion 31 at least partially.

[0133] Exemplarily, in the direction parallel to the winding axis K of the first pole piece 21, a part of each turn of the first tab layer 2111 overlaps with the first connection portion 31; or, in the direction parallel to the winding axis K of the first pole piece 21, all of each turn of the first tab layer 2111 overlaps with the first connection portion 31.

[0134] In some examples, the first connection portion 31 is welded to the first tab 211, that is to say, the first connection portion 31 is welded to each turn of the first tab layer 2111.

[0135] Exemplarily, it can be achieved by adjusting the structure of the first current collector 30 itself, so that the first connecting portion 31 can at least partially overlap with each turn of the first tab layer 2111 in a direction parallel to the winding axis K of the first electrode tab 21. For example, increasing the coverage area of the first connecting portion 31 or extending the first connecting portion 31 in a direction perpendicular to and away from the winding axis K, etc. It can also be achieved by adjusting the first tab 211 so that the first connecting portion 31 can at least partially overlap with each turn of the first tab layer 2111 in a direction parallel to the winding axis K of the first electrode tab 21. For example, increasing the thickness of each turn of the first tab layer 2111, increasing the dimension of each turn of the first tab layer 2111 in a direction parallel to the winding axis K of the first electrode tab 21, or converging multiple turns of the first tab layer 2111 in a direction close to the winding axis K, etc.

[0136] The above technical solution can enable the first connecting portion 31 of the first current collector 30 to cover each turn of the first tab layer 2111, so that the first current collector 30 can be directly connected to each turn of the first tab layer 2111, including the first tab layer 2111 located on the outer ring. Furthermore, each turn of the first tab layer 2111 can directly form a current flow with the current collector, reducing the conduction path between the current collector and each turn of the first tab layer 2111, so as to improve the current-carrying capacity of the battery cell 6, reduce the risk of lithium plating in the battery cell 6, and thus effectively improve the reliability of the battery cell 6.

[0137] In some embodiments, multiple turns of the first tab layer 2111 are converged in a direction close to the winding axis K.

[0138] Exemplarily, after the first tab 211 is wound in the winding direction X, the first tab 211 is generally cylindrical, and there is a gap between adjacent two turns of the first tab layer 2111. The first tab 211 is flattened to converge multiple turns of the first tab layer 2111 in a direction close to the winding axis K and gather them together, thereby compacting the first tab 211 and forming a dense structure, reducing the gap between multiple turns of the first tab layer 2111, and facilitating the welding of the first tab 211 to the first current collector 30. Among them, the flattening process is to shape the first tab 211 through a flattening device.

[0139] The above technical solution can increase the inward extension range of the outer ring first tab layer 2111, thereby further reducing the connection difficulty between the outer ring first tab layer 2111 and the first current collector 30.

[0140] In some embodiments, the dimension of multiple turns of the first tab layer 2111 in a direction parallel to the winding axis K gradually increases from the inside to the outside.

[0141] It should be noted that when the multi-turn first tab layer 2111 converges in the direction close to the winding axis K, the dimension of the multi-turn first tab layer 2111 in the direction parallel to the winding axis K mentioned in the embodiments of the present application refers to the dimension of the multi-turn first tab layer 2111 in the direction parallel to the winding axis K after being flattened.

[0142] Exemplarily, the inner end of the first tab 211 is the head end of the first turn of the first tab layer 2111. The tail end of the first turn of the first tab layer 2111 is aligned with the head end of the first turn of the first tab layer 2111 in the radial direction of the first tab 211. The first turn of the first tab layer 2111 surrounds the winding axis K for one turn. Correspondingly, the tail end of the first turn of the first tab layer 2111 is the head end of the second turn of the first tab layer 2111, and so on. The multi-turn first tab layer 2111 is connected end to end along the winding direction X. The first turn of the first tab layer 2111 is located in the innermost circle, the second turn of the first tab layer 2111 is located on the outer periphery of the first turn of the first tab layer 2111, and so on.

[0143] The dimension of the multi-turn first tab layer 2111 in the direction parallel to the winding axis K gradually increases from the inside to the outside. It can be understood that from the innermost first tab layer 2111 to the outermost first tab layer 2111, the dimensions of each turn of the first tab layer 2111 in the direction parallel to the winding axis K increase in sequence. As an example, the dimension of the second turn of the first tab layer 2111 in the direction parallel to the winding axis K is greater than the dimension of the first turn of the first tab layer 2111 in the direction parallel to the winding axis K, the dimension of the third turn of the first tab layer 2111 in the direction parallel to the winding axis K is greater than the dimension of the second turn of the first tab layer 2111 in the direction parallel to the winding axis K, and so on.

[0144] That is to say, the dimension of the Nth turn of the first tab layer 2111 in the direction parallel to the winding axis K is greater than the dimension of the (N - 1)th turn of the first tab layer 2111 in the direction parallel to the winding axis K.

[0145] It can be understood that the larger the dimension of the first tab 211 in the direction parallel to the winding axis K, the more convenient it is to realize the direct connection between the first tab 211 and the first current collector 30. And the greater the difficulty of directly connecting the first tab layer 2111 closer to the outer circle with the first current collector 30.

[0146] Thus, in the above technical solution, the dimension of the first tab layer 2111 closer to the outer circle in the direction parallel to the winding axis K is larger, which can further reduce the connection difficulty between the first tab layer 2111 closer to the outer circle and the first current collector 30.

[0147] Figure 11 It is a schematic structural diagram of a first pole piece 21 provided by some embodiments of the present application.

[0148] Continue to refer Figure 11 In some embodiments, the first electrode tab 211 includes a first portion 2112 and a second portion 2113, wherein the first portion 2112 is connected to one end of the second portion 2113 along the winding direction X, and the first portion 2112 surrounds the outer circumference of the second portion 2113. A first dimension d1 of the first portion 2112 along a direction parallel to the winding axis K is greater than a second dimension d2 of the second portion 2113 along a direction parallel to the winding axis K.

[0149] It should be noted that, in the case where the multiple turns of the first pole tab layer 2111 are gathered in the direction close to the winding axis K, the end of the first portion 2112 connected to the second portion 2113 along the winding direction X mentioned in the embodiment of the present application refers to the end of the first portion 2112 connected to the second portion 2113 along the winding direction X after the first pole tab 211 is flattened. Similarly, the first dimension d1 of the first portion 2112 in the direction parallel to the winding axis K is greater than the second dimension d2 of the second portion 2113 in the direction parallel to the winding axis K, which means that the first dimension d1 of the first portion 2112 in the direction parallel to the winding axis K after flattening is greater than the second dimension d2 of the second portion 2113 in the direction parallel to the winding axis K after flattening.

[0150] Exemplarily, when the multi-turn first tab layer 2111 is N-turn first tab layer 2111, the first portion 2112 forms N1-turn first tab layer 2111 after winding, and the second portion 2113 forms N2-turn first tab layer 2111 after winding, and N1+N2=N. N1, N2 and N can all be integers greater than 1.

[0151] Of course, alternatively, the second portion 2113 may be less than one circle around the winding axis K.

[0152] For example, N2 turns may be, but are not limited to, 1 / 3 turn, 1 / 2 turn, 2 / 3 turn, or 3 / 4 turn.

[0153] The above technical solution can reduce the difficulty of preparing the electrode assembly 20 as a whole while further reducing the difficulty of connecting the first pole lug layer 2111 close to the outer circle with the first current collector 30 by setting the first pole lug 2111 to a first part 2112 and a second part 2113 of different sizes along a direction parallel to the winding axis K, and the first size d1 of the first part 2112 along the direction parallel to the winding axis K is greater than the second size d2 of the second part 2113 along the direction parallel to the winding axis K, which is beneficial to reducing the overall cost of the battery cell 6.

[0154] Figure 12Schematic diagram of another structure of the first pole piece 21 provided by some embodiments of the present application.

[0155] Continue to refer to Figure 12 , in some embodiments, the first tab 211 further includes a third portion 2114, and the third portion 2114 is connected between the first portion 2112 and the second portion 2113. In the winding direction X, the third dimension d3 of the third portion 2114 in the direction parallel to the winding axis K gradually increases.

[0156] It should be noted that in the case where multiple turns of the first tab layer 2111 converge in the direction close to the winding axis K, the connection of the third portion 2114 mentioned in the embodiments of the present application between the first portion 2112 and the second portion 2113 means that the third portion 2114 is connected between the first portion 2112 and the second portion 2113 after the first tab 211 is flattened. Similarly, the third dimension d3 of the third portion 2114 in the direction parallel to the winding axis K refers to the third dimension d3 of the third portion 2114 in the direction parallel to the winding axis K after being flattened.

[0157] Exemplarily, in the case where the multiple turns of the first tab layer 2111 are N turns of the first tab layer 2111, the first portion 2112 forms M1 turns of the first tab layer 2111 after winding, the second portion 2113 forms M2 turns of the first tab layer 2111 after winding, and the third portion 2114 forms M3 turns of the first tab layer 2111 after winding, and M1 + M2 + M3 = N. Among them, M1, M2, M3, and N can all be integers greater than 1.

[0158] Of course, alternatively, the second portion 2113 surrounding the winding axis K can be less than one turn.

[0159] For example, M2 turns can be but are not limited to 1 / 3 turn, 1 / 2 turn, 2 / 3 turn, or 3 / 4 turn. The third portion 2114 surrounding the winding axis K can be less than one turn. For example, M3 turns can be but are not limited to 1 / 3 turn, 1 / 2 turn, 2 / 3 turn, or 3 / 4 turn.

[0160] Through the introduction of the third portion 2114, in the winding direction X, the third dimension d3 of the third portion 2114 in the direction parallel to the winding axis K gradually increases. The third portion

[0161] 2114 can form a transition between the first portion 2112 and the second portion 2113, reduce the influence of the dimensional mutation between the first portion 2112 and the second portion 2113 on the overall structural stability of the first tab 211, and can effectively improve the overall reliability of the battery cell 6.

[0162] In some embodiments, the first current collector 30 further includes a first main body portion 32. The first connecting portion 31 is connected to the first main body portion 32. The first connecting portion 31 includes a first convex portion 311 that protrudes from a surface of the first main body portion 32 facing the first tab 211 and abuts against the first tab 211.

[0163] The first convex portion 311 is configured to press against the first tab 211 so that the first convex portion 311 and the first tab 211 are in close contact, facilitating the connection of the first convex portion 311 and the first tab 211 by an external device. Exemplarily, the first convex portion 311 presses against the first tab 211. In this way, when welding the first convex portion 311 and the first tab 211, the risk of false soldering can be reduced, and the connection strength between the first convex portion 311 and the first tab 211 can be improved.

[0164] In some examples, the first main body portion 32 is generally in the shape of a flat plate.

[0165] In some embodiments, the first main body portion 32 contacts the first tab 211 to increase the current-carrying area between the first current collector 30 and the first tab 211 and improve the current-carrying capacity. The first convex portion 311 presses the first tab 211 to cause a local depression of the first tab 211, so that the first main body portion 32 and the first convex portion 311 can contact the first tab 211 simultaneously.

[0166] In some embodiments, the first connecting portion 31 further includes a first concave portion 312 corresponding to the first convex portion 311. The first concave portion 312 is recessed with respect to a surface of the first main body portion 32 facing away from the first tab 211.

[0167] The position of the first convex portion 311 corresponds to the position of the first concave portion 312. It can be understood that the projection of the first convex portion 311 in the thickness direction of the first current collector 30 at least partially overlaps with the projection of the first concave portion 312 in the thickness direction of the first current collector 30.

[0168] Exemplarily, the first concave portion 312 can be formed on the first main body portion 32 by stamping, so as to simultaneously form the first convex portion 311 that protrudes from a surface of the first main body portion 32 facing the first tab 211, which is beneficial to simplifying the overall manufacturing process flow. In other words, the first convex portion 311 can be formed by a stamping process, and the stamped position of the first current collector 30 forms the first concave portion 312.

[0169] After connecting the first connecting portion 31 to the first tab 211, some impurities may remain on the connection surface between the first connecting portion 31 and the first tab 211. Taking the welding process as an example, after welding, some metal particles will remain on the connection surface between the first connecting portion 31 and the first tab 211, and these metal particles may fall into the electrode assembly 20 and cause a short-circuit risk.

[0170] In the embodiment of the present application, by providing the first recess 312, the first recess 312 can accommodate metal particles to reduce the risk of the metal particles falling into the electrode assembly 20. In addition, the first recess 312 can also reduce the space occupied by the first current collector 30 in the direction parallel to the winding axis K.

[0171] In some embodiments, the battery cell 6 further includes a first adsorbent, and at least a part of the first adsorbent is accommodated in the first recess 312.

[0172] In some examples, the first adsorbent is formed by curing an insulating colloid. Specifically, after connecting the first connecting portion 31 to the first tab 211, an external device drops an insulating colloid into the first recess 312, and the insulating colloid forms the first adsorbent after curing.

[0173] In other examples, the first adsorbent is an insulating patch. Specifically, after connecting the first connecting portion 31 to the first tab 211, an external device places an insulating patch in the first recess 312 and bonds the insulating patch in the first recess 312.

[0174] In some embodiments, the first adsorbent is completely accommodated in the first recess 312.

[0175] The first adsorbent of the above technical solution is used to fix metal particles to further reduce the risk of the metal particles falling into the electrode assembly 20. In addition, the first recess 312 can also provide space for the first adsorbent and reduce the space occupied by the first adsorbent in the direction parallel to the winding axis K.

[0176] In some embodiments, the housing 10 further includes a second electrode lead-out portion 12. The electrode assembly 20 further includes a second electrode plate wound along the winding direction X. The second electrode plate has a polarity opposite to that of the first electrode plate 21. The second electrode plate is provided with a second tab 221 at one end facing the second electrode lead-out portion 12. The second tab 221 is wound along the winding direction X and includes multiple turns of second tab layers 2211. The battery cell 6 further includes a second current collector, and the second current collector is connected between the second electrode lead-out portion 12 and the second tab 221. The second current collector includes a second connecting portion for connecting the second tab 221. In the direction parallel to the winding axis K, the second connecting portion at least partially overlaps with each turn of the second tab layers 2211.

[0177] Exemplarily, the electrode assembly 20 includes a first electrode plate 21, a second electrode plate, and a separator. The separator is used to separate the first electrode plate 21 and the second electrode plate. The first electrode plate 21 and the second electrode plate have opposite polarities. In other words, one of the first electrode plate 21 and the second electrode plate is a positive electrode plate, and the other of the first electrode plate 21 and the second electrode plate is a negative electrode plate.

[0178] The first pole piece 21, the second pole piece, and the separator are all strip-shaped structures. The first pole piece 21, the second pole piece, and the separator are wound together around the winding axis K to form a wound structure. The wound structure can be a cylindrical structure, a flat structure, or a structure of other shapes.

[0179] The first pole tab 211 is the part of the first pole piece 21 that is not coated with the active material layer, and the second pole tab 221 is the part of the second pole piece that is not coated with the active material layer. Correspondingly, one of the first pole tab 211 and the second pole tab 221 is a pole tab with a positive polarity, and the other is a pole tab with a negative polarity.

[0180] The second electrode lead-out portion 12 is used to lead out the current in the electrode assembly 20 to output the electric energy generated by the electrode assembly 20. The second electrode lead-out portion 12 can be an end cap, a housing, or other parts of the outer shell 10, as long as it can lead out the current. For example, in some examples, the end cap serves as the second electrode lead-out portion 12 and is electrically connected to the electrode assembly 20. Alternatively, the outer shell 10 further includes an electrode terminal provided on the end cap, and the electrode terminal serves as the second electrode lead-out portion 12 and is electrically connected to the electrode assembly 20.

[0181] It can be understood that the second electrode lead-out portion 12 is used to be electrically connected to other battery cells 6 through a bus bar to achieve the series or parallel connection of different battery cells 6.

[0182] The two ends of the second pole tab 221 along the winding direction X are respectively an inner end and an outer end. In this embodiment, the inner end of the second pole tab 221 is used as a reference to divide the second pole tab layer 2211. The winding direction X is perpendicular to the winding axis K.

[0183] Specifically, the inner end of the second pole tab 221 is the starting end of the first turn of the second pole tab layer 2211. The ending end of the first turn of the second pole tab layer 2211 is aligned with the starting end of the first turn of the second pole tab layer 2211 in the radial direction of the second pole tab 221. The first turn of the second pole tab layer 2211 surrounds the winding axis K for one circle. Correspondingly, the ending end of the first turn of the second pole tab layer 2211 is the starting end of the second turn of the second pole tab layer 2211, and so on. Multiple turns of the second pole tab layer 2211 are connected end to end along the winding direction X. When dividing the second pole tab layer 2211, the starting end of each turn of the second pole tab layer 2211 is aligned with the inner end of the second pole tab 221 in the radial direction of the second pole tab 221. Among them, the radial direction of the second pole tab 221 is perpendicular to the winding axis K and passes through the winding axis K.

[0184] Exemplarily, the inner end and the outer end of the second pole tab 221 are aligned in the radial direction of the second pole tab 221. In this way, each turn of the pole tab layer surrounds the winding axis K for one circle.

[0185] Of course, alternatively, there is a portion at the tail of the second pole lug 221, which surrounds the winding axis K for less than one circle. For example, the portion can surround the winding axis K for 1 / 3, 1 / 2, 2 / 3 or 3 / 4 of a circle.

[0186] After winding is completed, the second pole lug 221 is generally cylindrical, and a gap is left between two adjacent turns of the second pole lug layer 2211. The embodiment of the present application can process the second pole lug 221 to reduce the gap between the second pole lug layers 2211, so as to facilitate the connection of the second pole lug 221 with the second current collector. For example, the embodiment of the present application can perform a flattening process on the second pole lug 221 so that multiple turns of the second pole lug layer 2211 are gathered and assembled together. The flattening process is to shape the second pole lug 221 by a flattening device to compact the second pole lug 221 and form a dense structure, reduce the gap between multiple turns of the second pole lug layer 2211, and facilitate the welding of the second pole lug 221 with the second current collector. Alternatively, the embodiment of the present application can also fill the conductive material between two adjacent turns of the second pole lug layer 2211 to reduce the gap between the pole lug layers.

[0187] The second current collector is used to realize the electrical connection between the second electrode lead-out portion 12 and the second electrode tab 221. The second connecting portion is used to connect the second connecting portion of the second electrode tab 221.

[0188] The second current collector may be directly connected to the second electrode lead-out portion 12, or may be restricted on the second electrode lead-out portion 12 by other components. As an example, the second current collector and the second electrode lead-out portion 12 may be connected by, but not limited to, welding, riveting, bonding, or clamping.

[0189] The second current collector may be directly connected to the second pole tab 221, or may be restricted on the second pole tab 221 by other components. As an example, the second current collector and the second pole tab 221 may be connected by, but not limited to, welding, riveting, bonding or clamping.

[0190] The projection shape of the second connection portion in the thickness direction of the second current collecting member may be, but is not limited to, a rectangle, a triangle, a V shape, a W shape, a straight line or a curve, etc. The thickness direction of the second current collecting member is parallel to the winding axis K.

[0191] In the direction parallel to the winding axis K of the second pole piece, the second connecting portion at least partially overlaps with each circle of the second pole lug layer 2211. In other words, the projection of the second connecting portion in the direction parallel to the winding axis K of the second pole piece at least partially overlaps with the projection of each circle of the second pole lug layer 2211 in the direction parallel to the winding axis K of the second pole piece. In other words, in the direction parallel to the winding axis K of the second pole piece, each circle of the second pole lug layer 2211 at least partially overlaps with the second connecting portion.

[0192] Exemplarily, in a direction parallel to the winding axis K of the second pole piece, a part of each turn of the second tab layer 2211 overlaps with the second connecting portion; or, in a direction parallel to the winding axis K of the second pole piece, all of each turn of the second tab layer 2211 overlaps with the second connecting portion.

[0193] In some examples, the second connecting portion is welded to the second tab 221, that is to say, the second connecting portion is welded to each turn of the second tab layer 2211.

[0194] The above technical solution can enable the second connecting portion of the second current collector to cover each turn of the second tab layer 2211, so that the second current collector can be directly connected to each turn of the second tab layer 2211, including the second tab layer 2211 located on the outer circle. Furthermore, each turn of the second tab layer 2211 can directly form a current flow with the current collector, reducing the conduction path between the current collector and each turn of the second tab layer 2211, so as to further improve the over-current capacity of the battery cell 6, further reduce the risk of lithium deposition in the battery cell 6, and thus can further improve the reliability of the battery cell 6.

[0195] It can be understood that the second tab 221 in the embodiment of the present application has the same structural principle as the first tab 211 provided in the embodiment of the present application. For the specific details of the second tab 221, reference can be made to the corresponding part of the description of the first tab 211 described in the above embodiment of the present application. For the sake of brevity, it will not be elaborated here.

[0196] In some embodiments, multiple turns of the second tab layer 2211 converge in a direction close to the winding axis K.

[0197] The above technical solution can increase the range of the outer second tab layer 2211 extending inward, thereby further reducing the connection difficulty between the outer second tab layer 2211 and the second current collector.

[0198] In some embodiments, the dimension of multiple turns of the second tab layer 2211 in a direction parallel to the winding axis K gradually increases from the inside to the outside.

[0199] The above technical solution is such that the dimension of the second tab layer 2211 closer to the outer circle in a direction parallel to the winding axis K is larger, which can further reduce the connection difficulty between the second tab layer 2211 closer to the outer circle and the second current collector.

[0200] In some embodiments, the second tab 221 includes a fourth part and a fifth part. The fourth part is connected to one end of the fifth part along the winding direction X, and the fourth part surrounds the outer periphery of the fifth part. The fourth dimension of the fourth part in a direction parallel to the winding axis K is greater than the fifth dimension of the fifth part in a direction parallel to the winding axis K.

[0201] In the above technical solution, by setting the second tab 221 to have a fourth part and a fifth part with different dimensions in the direction parallel to the winding axis K, and the fourth dimension of the fourth part in the direction parallel to the winding axis K being greater than the fifth dimension of the fifth part in the direction parallel to the winding axis K, it is possible to further reduce the connection difficulty between the second tab layer 2211 near the outer ring and the second current collector while reducing the overall preparation difficulty of the electrode assembly 20, which is beneficial to reducing the overall cost of the battery cell 6.

[0202] In some embodiments, the second tab 221 further includes a sixth part, and the sixth part is connected between the fourth part and the fifth part. In the winding direction X, the sixth dimension of the sixth part in the direction parallel to the winding axis K gradually increases.

[0203] In the above technical solution, by introducing the sixth part, in the winding direction X, the sixth dimension of the sixth part in the direction parallel to the winding axis K gradually increases, and the sixth part can form a transition between the fourth part and the fifth part, reducing the influence of the dimensional mutation between the fourth part and the fifth part on the overall structural stability of the second tab 221, and effectively improving the overall reliability of the battery cell 6.

[0204] It can be understood that the second current collector in the embodiments of the present application has the same structural principle as the first current collector 30 provided in the embodiments of the present application. For the specific details of the second current collector, reference can be made to the corresponding part of the first current collector 30 described in the above embodiments of the present application. For the sake of brevity, it will not be described in detail here.

[0205] In some embodiments, the second current collector further includes a second main body portion, a second connecting portion is connected to the second main body portion, the second connecting portion includes a second convex portion, and the second convex portion protrudes from the surface of the second main body portion facing the second tab 221 and abuts against the second tab 221.

[0206] The second convex portion presses against the second tab 221. In this way, when welding the second convex portion and the second tab 221, the risk of false soldering can be reduced, and the connection strength between the second convex portion and the second tab 221 can be improved.

[0207] In some examples, the second main body portion is generally flat.

[0208] In some embodiments, the second main body portion contacts the second tab 221 to increase the current-carrying area between the second current collector and the second tab 221 and improve the current-carrying capacity. The second convex portion presses the second tab 221 to make the second tab 221 locally recessed, so that the second main body portion and the second convex portion can contact the second tab 221 simultaneously.

[0209] In some embodiments, the second connecting portion further includes a second concave portion corresponding to the second convex portion. The second concave portion is recessed with respect to a surface of the second main body portion facing away from the second tab 221.

[0210] In the embodiments of the present application, by providing the second concave portion, the second concave portion can accommodate metal particles and reduce the risk of the metal particles falling into the electrode assembly 20. In addition, the second concave portion can also reduce the space occupied by the second current collector in the direction parallel to the winding axis K.

[0211] In some embodiments, the battery cell 6 further includes a second adsorbent, and at least a part of the second adsorbent is received in the second concave portion.

[0212] The second adsorbent of the above technical solution is used to fix the metal particles to further reduce the risk of the metal particles falling into the electrode assembly 20. In addition, the second concave portion can also provide space for the second adsorbent and reduce the space occupied by the second adsorbent in the direction parallel to the winding axis K.

[0213] It can be understood that the second adsorbent in the embodiments of the present application has the same structural principle as the first adsorbent provided in the embodiments of the present application. For the specific details of the second adsorbent, reference can be made to the corresponding part of the first adsorbent described in the above embodiments of the present application. For the sake of brevity, it will not be elaborated here.

[0214] In some embodiments, the first electrode lead-out portion 11 and the second electrode lead-out portion 12 are disposed opposite to each other in the direction parallel to the winding axis K.

[0215] Exemplarily, the housing 10 includes a housing body. The first electrode lead-out portion 11 and the second electrode lead-out portion 12 are respectively connected to two ends of the housing body in the direction parallel to the winding axis K. From the outer shape of the electrode assembly 20, the electrode assembly 20 includes an electrode main body, a first tab 211 and a second tab 221. The first tab 211 and the second tab 221 protrude from the electrode main body, and the first tab 211 and the second tab 221 are respectively located at two ends of the electrode main body in the direction parallel to the winding axis K.

[0216] The above technical solution reduces the difficulty of setting the first electrode lead-out portion 11 and the second electrode lead-out portion 12, and reduces the risk of short circuit of the battery cell 6.

[0217] In some embodiments, the battery cell 6 further includes a first adapter 40, and the first adapter 40 is connected between the first current collector 30 and the first electrode lead-out portion 11.

[0218] Exemplarily, the first adapter 40 is used to achieve the electrical connection between the first current collector 30 and the first electrode lead-out portion 11. The first adapter 40 can be directly connected to the first current collector 30, or can be restricted on the first current collector 30 through other components. As an example, the connection manner between the first adapter 40 and the first current collector 30 can be, but is not limited to, welding, riveting, bonding, or snap connection, etc.

[0219] The first adapter 40 can be directly connected to the first electrode lead-out portion 11, or can be restricted on the first electrode lead-out portion 11 through other components. As an example, the connection manner between the first adapter 40 and the first electrode lead-out portion 11 can be, but is not limited to, welding, riveting, bonding, or snap connection, etc.

[0220] By introducing the first adapter 40, the above technical solution can reduce the connection difficulty between the first current collector 30 and the first electrode lead-out portion 11, thereby facilitating the improvement of the product yield of the battery cell 6.

[0221] In some embodiments, the first adapter 40 is provided with a reinforcing rib 41.

[0222] Exemplarily, the reinforcing rib 41 can be one or more. As an example, the number of the reinforcing ribs 41 is multiple, and the multiple reinforcing ribs 41 are arranged at intervals on the first adapter 40.

[0223] The reinforcing rib 41 can be directly connected to the first adapter 40, or can be restricted on the first adapter 40 through other components. As an example, the connection manner between the reinforcing rib 41 and the first adapter 40 can be, but is not limited to, bolt connection, welding, riveting, bonding, or snap connection, etc.

[0224] In some examples, the reinforcing rib 41 and the first adapter 40 are of an integrally formed structure. On the one hand, there is no need to connect the reinforcing rib 41 and the first adapter 40 through an additional connection process, which simplifies the manufacturing process flow. At the same time, compared with connecting the reinforcing rib 41 and the first adapter 40 through an additional connection process, the connection between the integrally formed reinforcing rib 41 and the first adapter 40 has higher connection firmness.

[0225] By providing the reinforcing rib 41 on the first adapter 40, the above technical solution can effectively improve the structural strength of the first adapter 40, reduce the risk of fracture, and thus can effectively improve the overall reliability of the battery cell 6.

[0226] In some embodiments, the battery cell 6 further includes a second adapter, and the second adapter is connected between the second current collector and the second electrode lead-out portion 12. By introducing the second adapter, the connection difficulty between the second current collector and the second electrode lead-out portion 12 can be reduced, thereby facilitating the improvement of the product yield of the battery cell 6.

[0227] It can be understood that the second adapter of the embodiment of the present application has the same structural principle as the first adapter 40 provided in the embodiment of the present application. For the specific details of the second adapter, reference can be made to the corresponding part of the first adapter 40 described in the above embodiment of the present application. For the sake of brevity, it will not be elaborated here.

[0228] In some embodiments, reinforcing ribs 41 are provided on the first adapter 40. It can effectively improve the structural strength of the second adapter, reduce the risk of fracture, and thus effectively improve the overall reliability of the battery cell 6.

[0229] In some embodiments, the battery cell 6 is a cylindrical battery cell.

[0230] According to some embodiments of the present application, the present application further provides a battery, including the battery cell 6 of any of the above solutions.

[0231] According to some embodiments of the present application, the present application further provides an electrical device, including the battery cell 6 of any of the above solutions, and the battery cell 6 is used to provide electrical energy.

[0232] To better understand the battery cell 6 provided in the embodiment of the present application, based on the same inventive concept, embodiments of the above battery cell 6 in practical applications are provided here for illustration.

[0233] The embodiment of the present application provides a battery cell 6, which includes a housing 10, an electrode assembly 20, and a first current collector 30. The housing 10 includes a first electrode lead-out portion 11; the electrode assembly 20 is accommodated in the housing 10. The electrode assembly 20 includes a first electrode tab 21 wound along a winding direction X. One end of the first electrode tab 21 facing the first electrode lead-out portion 11 is provided with a first tab 211. The first tab 211 is wound along the winding direction X and includes multiple layers of first tab layers 2111. The multiple layers of first tab layers 2111 converge in a direction close to the winding axis K, and the dimension of the multiple layers of first tab layers 2111 in a direction parallel to the winding axis K of the first electrode tab 21 gradually increases from the inside to the outside. The first current collector 30 is connected between the first electrode lead-out portion 11 and the first tab 211. The first current collector 30 includes a first connection portion 31 for connecting the first tab 211. In a direction parallel to the winding axis K, the first connection portion 31 at least partially overlaps with each layer of the first tab layers 2111.

[0234] The above technical solution can reduce the connection difficulty between the first tab layer 2111 near the outer ring and the first current collector 30, so that the first connection part 31 of the first current collector 30 can cover each turn of the first tab layer 2111, enabling the first current collector 30 to be directly connected to each turn of the first tab layer 2111, including the first tab layer 2111 located in the outer ring. Furthermore, each turn of the first tab layer 2111 can directly form a current flow with the current collector, reducing the conduction path between the current collector and each turn of the first tab layer 2111, so as to improve the over-current capacity of the battery cell 6 and reduce the risk of lithium plating in the battery cell 6, thereby effectively improving the reliability of the battery cell 6.

[0235] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0236] 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 described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be covered within the scope of the claims and the description of the present application. In particular, as long as there is no structural conflict, the 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, characterized in that, Comprising: A housing including a first electrode lead-out portion; An electrode assembly accommodated in the housing, the electrode assembly including a first pole piece wound along a winding direction, the first pole piece having a first tab at one end facing the first electrode lead-out portion, the first tab being wound along the winding direction and including multiple turns of first tab layers; A first current collector connected between the first electrode lead-out portion and the first tab, the first current collector including a first connection portion for connecting the first tab, and in a direction parallel to the winding axis of the first pole piece, the first connection portion at least partially overlaps with each turn of the first tab layers.

2. The battery cell according to claim 1, characterized in that, The multiple turns of the first tab layers converge in a direction close to the winding axis.

3. The battery cell according to claim 1, wherein The dimensions of the multiple turns of the first tab layers in a direction parallel to the winding axis gradually increase from the inside to the outside.

4. The battery cell according to claim 1, characterized in that, The first tab includes a first portion and a second portion, the first portion being connected to one end of the second portion along the winding direction, and the first portion surrounding the outer periphery of the second portion; A first dimension of the first portion in a direction parallel to the winding axis is greater than a second dimension of the second portion in a direction parallel to the winding axis.

5. The battery cell according to claim 4, wherein The first tab further includes a third portion, the third portion being connected between the first portion and the second portion; In the winding direction, a third dimension of the third portion in a direction parallel to the winding axis gradually increases.

6. The battery cell according to claim 1, characterized in that, The first current collector further includes a first main body portion, the first connection portion being connected to the first main body portion, the first connection portion including a first convex portion protruding from a surface of the first main body portion facing the first tab and abutting against the first tab.

7. The battery cell according to claim 6, wherein, The first connection portion further includes a first concave portion corresponding to the first convex portion, the first concave portion being recessed with respect to a surface of the first main body portion facing away from the first tab.

8. The battery cell according to claim 1, characterized in that, The housing further includes a second electrode lead-out portion; The electrode assembly further includes a second pole piece wound along the winding direction, the second pole piece having a polarity opposite to that of the first pole piece, the second pole piece having a second tab at one end facing the second electrode lead-out portion, the second tab being wound along the winding direction and including multiple turns of second tab layers; The battery cell further includes a second current collector connected between the second electrode lead-out portion and the second tab, the second current collector including a second connection portion for connecting the second tab, and in a direction parallel to the winding axis, the second connection portion at least partially overlaps with each turn of the second tab layers.

9. The battery cell according to claim 8, characterized in that, The first electrode lead-out portion and the second electrode lead-out portion are oppositely arranged in a direction parallel to the winding axis.

10. The battery cell according to claim 1, characterized in that, The battery cell further includes a first adapter connected between the first current collector and the first electrode lead-out portion.

11. The battery cell according to claim 10, wherein, Reinforcing ribs are provided on the first adapter.

12. The battery cell according to any one of claims 1-11, characterized in that, The battery cell is a cylindrical battery cell.

13. A battery, characterized in that, Including a plurality of battery cells according to any one of claims 1-12.

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

Images