Battery monomer, pole piece, battery device and power utilization device

Abstract

The utility model provides a battery monomer, a pole piece, a battery device and a power utilization device. The battery cell includes: a case; the electrode assembly is arranged in the shell, the electrode assembly comprises a pole piece, the pole piece comprises a pole lug and a current collector, the pole lug comprises a first end and a second end which are oppositely arranged, the first end is connected with the current collector, the second end is arranged away from the current collector, at least part of the pole piece further comprises a reinforcing piece, and the reinforcing piece is arranged on the pole lug and extends from the first end to the second end.

Description

Technical Field

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

[0002] Batteries are widely used in electronic devices such as mobile phones, laptops, electric vehicles, electric airplanes, electric boats, electric toy cars, electric toy boats, electric toy airplanes and power tools, etc.

[0003] During the battery production process, the tabs are prone to damage and cracking, which leads to reduced battery cell performance and insufficient stability of the battery cells. Utility Model Content

[0004] In view of the above problems, the present application provides a battery cell, a pole piece, a battery device and an electrical device, which can improve the problem of tab cracking and enhance the stability of the battery cell.

[0005] In a first aspect, an embodiment of the present application provides a battery cell, comprising: a shell; an electrode assembly, arranged in the shell, the electrode assembly including a pole piece, the pole piece including a current collector and an active material layer, the current collector including a current collecting portion and a pole ear connected to each other, the active material layer being arranged on the current collecting portion, the pole ear including a first end and a second end arranged opposite to each other, the first end being connected to the current collecting portion, and the second end being arranged away from the current collecting portion, wherein at least part of the pole piece also includes a reinforcement, the reinforcement being arranged on the pole ear and extending from the first end toward the second end.

[0006] In the solution of the embodiment of the present application, the battery cell includes a shell and an electrode assembly, the electrode assembly is accommodated in the shell, the electrode assembly includes a pole piece, the pole piece includes a current collector and an active material layer, the current collector includes a current collecting part and a pole ear connected to each other, the active material layer is arranged on the current collecting part, the pole ear includes a first end and a second end arranged opposite to each other, the first end is connected to the current collecting part, and the second end is arranged away from the current collecting part. At least part of the pole piece also includes a reinforcement piece, the reinforcement piece is arranged on the pole ear and extends from the first end toward the second end. By arranging the reinforcement piece to improve the strength of the pole ear at the first end, the problem of the pole ear cracking under the action of external force is improved, and the stability of the battery cell is improved.

[0007] In some embodiments, at least two reinforcing members are spaced apart on at least one surface of the tab in the thickness direction.

[0008] In the solution of the embodiment of the present application, at least two reinforcing members are arranged at intervals on at least one side surface of the tab in the thickness direction, so that the size of the reinforcing member can be reduced while improving the strength of the tab, saving the material cost of the reinforcing member, and reducing the impact of the reinforcing member on the bending space of the tab and the weight of the electrode assembly, thereby reducing the processing difficulty of the battery cell.

[0009] In some embodiments, the reinforcing pieces are disposed on both sides of the tab in the thickness direction.

[0010] In the embodiment of the present application, the reinforcing members are arranged on both sides of the tab in the thickness direction to enhance the supporting effect of the reinforcing members on the surfaces on both sides of the tab in the thickness direction, further reducing the risk of the tab cracking under the action of external force.

[0011] In some embodiments, the surface of the tab in the thickness direction includes interconnected welding areas and glue-coated areas, the tabs are interconnected in the welding areas, and the reinforcement is disposed in the glue-coated areas.

[0012] In the solution of the embodiment of the present application, the surface of the tab in the thickness direction includes interconnected welding areas and glue-coated areas. The tabs are interconnected in the welding areas, and the reinforcement parts are arranged in the glue-coated areas. By setting the reinforcement parts and the welding areas at intervals, the problem of low tab welding strength and poor welding quality in the subsequent tab welding stage due to the reinforcement parts invading the welding areas is improved.

[0013] In some embodiments, a reinforcement member is disposed between the weld region and the first end.

[0014] In the solution of the embodiment of the present application, the reinforcement is arranged between the welding area and the first end. While the reinforcement improves the strength of the pole tab, the difficulty of setting the reinforcement on the pole tab is reduced, the material cost of the reinforcement is saved, the weight of the reinforcement is reduced, and the risk of the reinforcement invading the welding area is reduced, thereby improving the reliability of the battery cell.

[0015] In some embodiments, the surface area S1 of one side surface of the tab in the thickness direction, along the extension direction of the tab, between the first end and the welding region, and the surface area S2 of the reinforcement satisfy 0.2*S1≤S2≤S1.

[0016] In the solution of the embodiment of the present application, when the surface area S1 of the tab between the first end and the welding area and the surface area S2 of the reinforcement meet the above conditions, it can be ensured that the size of the reinforcement can be reduced while the reinforcement can provide sufficient strength for the tab, thereby reducing the weight of the reinforcement, saving the material cost of the reinforcement, and improving the energy density of the battery cell.

[0017] In some embodiments, the thickness D1 of the active material layer and the thickness D2 of the reinforcing member satisfy D2≤D1.

[0018] In the embodiment of the present application, when the thickness D1 of the active material layer and the thickness D2 of the reinforcement meet the above conditions, it is convenient to bend and fold the tabs together, and reduce the thickness of the tabs after folding, so as to improve the utilization rate of the space in the shell.

[0019] In some embodiments, the dielectric constant ε of the reinforcing member satisfies ε≤5F / m.

[0020] In the embodiment of the present application, when the dielectric constant ε of the reinforcing member satisfies the above conditions, the reinforcing member has good insulation capability, so that the reinforcing member can improve the problem of short circuit in the battery cell caused by inverted insertion of the tab.

[0021] In some embodiments, the electrode sheet includes a positive electrode sheet and a negative electrode sheet, the positive electrode sheet includes a positive current collector and a positive active material layer, the positive current collector includes a positive current collecting part and a positive electrode ear, and the positive active material layer is arranged on the positive current collecting part; the negative electrode sheet includes a negative current collector and a negative active material layer, the negative current collector includes a negative current collecting part and a negative electrode ear, and the negative active material layer is arranged on the negative current collecting part; the positive current collecting part includes a first part and a second part, the second part is arranged between the first part and the electrode ear, the negative current collecting part and the first part are arranged correspondingly, and the reinforcement extends to at least a portion of the surface of the positive active material layer of the second part.

[0022] In the solution of the embodiment of the present application, the positive current collecting part includes a first part and a second part, the second part is arranged between the first part and the electrode ear, the negative current collecting part and the first part are arranged correspondingly, and the reinforcement part extends to at least part of the surface of the positive electrode active material layer of the second part to block the embedding of lithium ions in the electrolyte, so as to improve the problem of lithium analysis in the second part of the positive electrode sheet caused by the excessively high lithium ion concentration in the second part of the positive current collector.

[0023] In some embodiments, the electrode assembly is formed by stacking multiple pole sheets, and a reinforcement is provided on at least one pole sheet at the end of the electrode assembly along the stacking direction of the pole sheets; or, the electrode assembly is formed by winding the pole sheets, and the reinforcement is provided on at least part of the pole sheets on the outside of the electrode assembly.

[0024] In the solution of the embodiment of the present application, in actual production, the outer pole piece of the electrode assembly is more easily damaged. Therefore, a reinforcement piece is set on the pole piece at the end or the outer side of the electrode assembly to improve the strength of the pole ear of the pole piece at the end or the outer side of the electrode assembly, reduce the risk of damage to the pole ear, thereby improving the overall stability of the electrode assembly, saving the material cost of the reinforcement piece, saving the internal space of the battery cell, improving the utilization rate of the internal space of the battery cell, and improving the energy density of the battery cell.

[0025] In a second aspect, an embodiment of the present application provides a pole piece, which is applied to the battery cell of the embodiment of the first aspect above, the pole piece includes a current collector and an active material layer, the current collector includes a current collecting portion and a pole lug connected to each other, the active material layer is arranged on the current collecting portion, the pole lug includes a first end and a second end arranged opposite to each other, the first end is connected to the current collecting portion, and the second end is arranged away from the current collecting portion, wherein at least part of the pole piece also includes a reinforcement piece, the reinforcement piece is arranged on the pole lug and extends from the first end toward the second end.

[0026] In the embodiment of the present application, the reinforcing member is arranged on the tab and extends from the first end toward the second end. By providing the reinforcing member to improve the strength of the tab at the first end, the problem of tab cracking under external force is improved, thereby improving the stability of the battery cell.

[0027] In some embodiments, at least two reinforcing members are spaced apart on at least one surface of the tab in the thickness direction.

[0028] In the solution of the embodiment of the present application, at least two reinforcing members are arranged at intervals on at least one side surface of the tab in the thickness direction, so that the size of the reinforcing member can be reduced while improving the strength of the tab, saving the material cost of the reinforcing member, and reducing the impact of the reinforcing member on the bending space of the tab and the weight of the electrode assembly, thereby reducing the processing difficulty of the battery cell.

[0029] In some embodiments, the reinforcing pieces are disposed on both sides of the tab in the thickness direction.

[0030] In the embodiment of the present application, the reinforcing members are arranged on both sides of the tab in the thickness direction to enhance the supporting effect of the reinforcing members on the surfaces on both sides of the tab in the thickness direction, further reducing the risk of the tab cracking under the action of external force.

[0031] In some embodiments, the surface of the tab in the thickness direction includes interconnected welding areas and glue-coated areas, the tabs are interconnected in the welding areas, and the reinforcement is disposed in the glue-coated areas.

[0032] In the solution of the embodiment of the present application, the surface of the tab in the thickness direction includes interconnected welding areas and glue-coated areas. The tabs are interconnected in the welding areas, and the reinforcement parts are arranged in the glue-coated areas. By setting the reinforcement parts and the welding areas at intervals, the problem of low tab welding strength and poor welding quality in the subsequent tab welding stage due to the reinforcement parts invading the welding areas is improved.

[0033] In a third aspect, an embodiment of the present application provides a battery device comprising the battery cell of the embodiment of the first aspect described above.

[0034] In a fourth aspect, an embodiment of the present application provides an electrical device, comprising the battery device of the embodiment of the third aspect described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference symbols are used throughout the drawings to represent the same components. In the drawings:

[0036] Figure 1 is a structural schematic diagram of a vehicle provided in one embodiment of the present application;

[0037] Figure 2 is a structural schematic diagram of a battery device provided in one embodiment of the present application;

[0038] Figure 3 This is a schematic structural diagram of a battery module provided in one embodiment of the application;

[0039] Figure 4 is an exploded view of a battery cell provided in one embodiment of the present application;

[0040] Figure 5 This is a schematic structural diagram of a pole piece of a battery cell provided in one embodiment of the present application;

[0041] Figure 6 is a schematic structural diagram of a pole piece of a battery cell provided in another embodiment of the present application;

[0042] Figure 7 This is a schematic structural diagram of a pole piece of a battery cell provided in one embodiment of the present application;

[0043] Figure 8 This is a schematic structural diagram of a pole piece of a battery cell provided in one embodiment of the present application;

[0044] Figure 9 This is a schematic diagram of a partial structure of an electrode assembly of a battery cell provided in one embodiment of the present application;

[0045] Figure 10 It is a partial structural schematic diagram of an electrode assembly of a battery cell pole piece provided in one embodiment of the present application.

[0046] Description of reference numerals:

[0047] 1. Vehicle; 101. Motor; 102. Controller;

[0048] 2. Battery device; 201. Battery module; 202. Box; 2021. First box; 2022. Second box; 3. Battery cell; 4. Housing; 5. Electrode assembly; 6. Top cover assembly;

[0049] 7. Pole sheet; 71. Current collector; 72. Active material layer; 711. Current collecting part; 712. Tab; 713. First end; 714. Second end; 715. Welding area; 716. Glue coating area; 73. Positive electrode sheet; 731. Positive current collector; 732. Positive active material layer; 7311. Positive current collecting part; 7312. Positive tab; 7313. First part; 7314. Second part; 74. Negative electrode sheet; 741. Negative current collector; 742. Negative active material layer; 7411. Negative current collecting part; 7412. Negative tab; 75. Reinforcement member. DETAILED DESCRIPTION

[0050] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0051] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in the embodiments of the present application should have the common meanings understood by technicians in the field to which the embodiments of the present application belong.

[0052] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limiting the embodiments of the present application.

[0053] In addition, the technical terms "first," "second," etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. In the description of the embodiments of the present application, the meaning of "plurality" is more than two, unless otherwise specifically defined.

[0054] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0055] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, a first feature being "above," "above," and "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is at a higher level than the second feature. A first feature being "below," "below," and "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0056] Currently, market developments indicate that power batteries are becoming increasingly widely used. They are not only used in energy storage systems such as hydropower, thermal, wind, and solar power plants, but are also widely used in electric vehicles like electric bicycles, electric motorcycles, and electric vehicles, as well as in military equipment and aerospace. As power battery applications continue to expand, market demand is also growing.

[0057] In this application, battery cells may include lithium-ion secondary battery cells, lithium-ion primary battery cells, lithium-sulfur battery cells, sodium-lithium-ion battery cells, sodium-ion battery cells, or magnesium-ion battery cells, and the embodiments of this application are not limited thereto. Battery cells may be cylindrical, flat, rectangular, or in other shapes, and the embodiments of this application are not limited thereto.

[0058] The battery referred to in the embodiments of this application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, the battery referred to in this application may include a battery module or a battery pack. A battery generally includes a casing that encloses one or more battery cells. The casing prevents liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0059] During the battery production process, the tabs are prone to damage and cracking.

[0060] During the processing of battery cells, some tabs are prone to cracking due to large deflection angles and complex stress conditions.

[0061] Based on the above problems, an embodiment of the present application provides a battery cell, which includes a shell and an electrode assembly, the electrode assembly is accommodated in the shell, the electrode assembly includes a pole piece, the pole piece includes a pole ear and a current collector, the pole ear includes a first end connected to the current collector and a second end facing away from the current collector, at least part of the pole piece also includes a reinforcement piece, the reinforcement piece is arranged on the pole ear and extends from the first end toward the second end, and the strength of the pole ear at the first end is improved by arranging the reinforcement piece to improve the problem of the pole ear cracking under the action of external force, thereby improving the stability of the battery cell.

[0062] The technical solutions described in the embodiments of the present application are applicable to battery devices and electrical devices using battery devices.

[0063] A battery cell includes an electrode assembly and electrolyte within a housing. The electrodes include a positive electrode and a negative electrode. The electrode assembly also includes a separator. A battery cell primarily operates by the movement of metal ions between the positive and negative electrodes.

[0064] Specifically, a positive electrode sheet includes a positive current collector and a positive active material layer, which is coated on the surface of the positive current collector. The positive current collector includes a positive current collector portion and a positive tab connected to the positive current collector portion. The positive current collector portion is coated with the positive active material layer, while the positive tab is not. For lithium-ion batteries, for example, the positive current collector can be aluminum or a composite material containing an aluminum coating. The positive active material layer includes a positive active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. A negative electrode sheet includes a negative current collector and a negative active material layer, which is coated on the surface of the negative current collector. The negative current collector includes a negative current collector portion and a negative tab connected to the negative current collector portion. The negative current collector portion is coated with the negative active material layer, while the negative tab is not. The negative current collector can be copper or a composite material containing a copper coating. The negative active material layer includes a negative active material, which can be carbon or silicon, for example. The material of the spacer can be PP (polypropylene) or PE (polyethylene).

[0065] Electrical devices may include vehicles, mobile phones, portable devices, laptop computers, ships, spacecraft, electric toys, and electric tools, etc. Vehicles may include fuel vehicles, gas vehicles, or new energy vehicles. New energy vehicles may include pure electric vehicles, hybrid vehicles, or extended-range vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Electric tools include 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 drills, concrete vibrators, and electric planers, etc. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical devices.

[0066] In the embodiment of the present application, the battery cell may be a secondary battery. A secondary battery refers to a battery cell that can be continuously used by activating active materials by charging after the battery cell is discharged.

[0067] The battery cells may be lithium-ion batteries, sodium-ion batteries, sodium-lithium-ion batteries, lithium metal batteries, sodium metal batteries, lithium-sulfur batteries, magnesium-ion batteries, nickel-metal hydride batteries, nickel-cadmium batteries, lead-acid batteries, etc., and the present invention does not limit this. The battery cells may be cylindrical, flat, rectangular, or other shapes, and the present invention does not limit this.

[0068] The battery device referred to in the embodiments of this application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, the battery device referred to in this application may include a battery module or battery pack. A battery pack generally includes a casing for enclosing one or more battery cells. The casing prevents liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0069] It should be understood that the technical solutions described in the embodiments of the present application are not limited to the battery devices and electrical equipment described above, but can also be applied to all battery devices including a box and electrical equipment using the battery devices. However, for the sake of simplicity, the following embodiments are explained using electric vehicles as an example.

[0070] Please refer to Figure 1 , Figure 1 A schematic structural diagram of a vehicle 1 provided for some embodiments of the present application. The vehicle 1 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery device 2 is provided inside the vehicle 1, and the battery device 2 may be provided at the bottom, head or tail of the vehicle 1. The battery device 2 may be used to power the vehicle 1, for example, the battery device 2 may serve as an operating power source for the vehicle 1. The vehicle 1 may further include a controller 102 and a motor 101, and the controller 102 is used to control the battery to power the motor 101, for example, for starting, navigating and operating power requirements of the vehicle 1 during driving.

[0071] In some embodiments of the present application, the battery device 2 can serve not only as an operating power source for the vehicle 1 , but also as a driving power source for the vehicle 1 , replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1 .

[0072] Figure 2 A schematic structural diagram of a battery device according to an embodiment of the present application is shown.

[0073] The battery device 2 mentioned in the embodiment of the present application may include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly may include multiple battery cells 3, and the multiple battery cells 3 are connected in series, parallel or mixed via a busbar.

[0074] In some embodiments, a battery cell assembly is generally formed by arranging a plurality of battery cells 3 .

[0075] As an example, the battery cell assembly may be a battery module 201, wherein the battery module 201 is formed by arranging and fixing a plurality of battery cells 3 to form an independent module. As an example, the battery module 201 may be formed by bundling the plurality of battery cells 3 with a cable tie.

[0076] In some embodiments, the battery device may be a battery pack, which includes a case 202 and one or more battery cell assemblies, wherein the battery cell assemblies are housed in the case 202 .

[0077] As an example, the battery cell assembly may be a battery module 201 , and the battery cell assembly may be accommodated in the box by fixing the battery module 201 in the box.

[0078] As an example, the battery cell assembly may also be housed in the box body 202 by directly fixing the plurality of battery cells 3 to the box body 202 .

[0079] As an example, housing 202 may include a first housing 2021 and a second housing 2022. The first housing 2021 and the second housing 2022 engage to form an enclosed space within housing 202 for accommodating battery cell assemblies. Enclosed here means covered or closed, and can be either sealed or unsealed. First housing 2021 may be a top cover or a bottom plate.

[0080] As an example, the box body 202 may include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are respectively connected to the frame, so that a closed space is formed inside the box body 202 to accommodate the battery cell assembly.

[0081] In some embodiments, the box 202 can be used as part of the chassis structure of the vehicle. For example, part of the box 202 can become at least a part of the floor of the vehicle, or part of the box 202 can become at least a part of the crossbeam and longitudinal beam of the vehicle.

[0082] Figure 3 A schematic structural diagram of a battery module 201 according to an embodiment of the present application is shown.

[0083] In some embodiments, as Figure 2 and Figure 3 As shown, there are multiple battery cells 3, which are first connected in series, in parallel, or in series to form a battery module 201. The multiple battery modules 201 are then connected in series, in parallel, or in series to form a whole, and are accommodated in a box 202.

[0084] The multiple battery cells 3 in the battery module 201 can be electrically connected via a busbar component to achieve parallel connection, series connection, or mixed connection of the multiple battery cells 3 in the battery module 201 .

[0085] In the present application, the battery cell 3 may include a lithium-ion battery cell, a sodium-ion battery cell, a magnesium-ion battery cell, etc., which is not limited in the embodiments of the present application.

[0086] Figure 4 : is an exploded view of a battery cell provided in one embodiment of the present application. Battery cell 3 refers to the smallest unit that makes up a battery. Figure 4 The battery cell 3 includes a top cover assembly 6, a shell 4 and an electrode assembly 5.

[0087] The electrode assembly 5 is a component in the battery cell 3 where electrochemical reactions occur. One or more electrode assemblies 5 may be contained in the housing 4. The electrode assembly 5 is mainly formed by winding or stacking electrode sheets, which are divided into positive electrode sheets and negative electrode sheets, 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 materials constitute the electrode body, and the parts of the positive electrode sheet and the negative electrode sheet without active materials each constitute the electrode ear. The positive electrode ear and the negative electrode ear may be located together at one end of the electrode body or respectively at both ends of the electrode body. During the charge and discharge process of the battery cell 3, the positive electrode active material and the negative electrode active material react with the electrolyte, and the electrode ears connect the electrode terminals to form a current loop.

[0088] The electrode assembly 5 may be a wound structure, a laminated structure, or a mixed structure of wound and laminated structures.

[0089] In some embodiments, the electrode assembly 5 is a wound structure in which the positive electrode sheet and the negative electrode sheet are wound into a wound structure.

[0090] In some embodiments, the electrode assembly 5 has a laminated structure. As an example, multiple positive and negative electrode sheets can be provided, and the multiple positive and negative electrode sheets can be alternately stacked. Multiple separators can be provided and respectively disposed between any adjacent positive or negative electrode sheets. Alternatively, the separators can be provided continuously and folded between any adjacent positive or negative electrode sheets.

[0091] In some embodiments, the shape of the electrode assembly 5 can be cylindrical, flat, or polygonal.

[0092] In some embodiments, the electrode assembly 5 is provided with tabs, which can conduct current from the electrode assembly. The tabs include a positive tab and a negative tab.

[0093] The battery cell 3 may include a shell 4. The shell 4 is a component used to cooperate with the top cover assembly 6 to form an internal environment of the battery cell 3, wherein the internal environment formed can be used to accommodate the electrode assembly 5, the electrolyte (not shown in the figure) and other components. The shell 4 can 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. In some embodiments, the shell 4 can be a sealed structure or a non-sealed structure. As an example, when the shell 4 is a non-sealed structure, the shell 4 plays a role in protecting the electrode assembly 5, and a sealing bag is further included between the shell 4 and the electrode assembly 5, and the sealing bag is used to encapsulate the electrode assembly and the electrolyte. Specifically, the sealing bag can be a bag-shaped insulating member or an aluminum-plastic film. When the shell 4 is a sealed structure, it is used to encapsulate components such as the electrode assembly 5 and the electrolyte.

[0094] As an example, the battery cell 3 can 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, and a polygonal battery. The polygonal battery is, for example, a hexagonal battery, etc. There is no special limitation in this application.

[0095] The housing 4 and the top cover assembly 6 can be separate components. One or more openings can be provided on the housing 4, and one or more top cover assemblies 6 cover the openings to form the internal environment of the battery cell 3. Alternatively, the top cover assembly 6 and the housing 4 can be integrated. Optionally, the top cover assembly 6 and the housing 4 can form a common connection surface before other components are inserted into the housing. When the interior of the housing 4 needs to be enclosed, the top cover assembly 6 is then placed to cover the housing 4.

[0096] See also Figure 5 , Figure 5 Schematic diagram of the structure of the pole piece 7 of the battery cell 3 provided in one embodiment of the present application.

[0097] First, as Figure 4 and Figure 5 As shown, an embodiment of the present application provides a battery cell 3, which includes a shell 4 and an electrode assembly 5. The electrode assembly 5 is arranged in the shell 4, and the electrode assembly 5 includes a pole piece 7. The pole piece 7 includes a current collector 71 and an active material layer 72. The current collector 71 includes a current collecting portion 711 and a pole ear 712 that are interconnected. The active material layer 72 is arranged on the current collecting portion 711. The pole ear 712 includes a first end 713 and a second end 714 that are relatively arranged. The first end 713 is connected to the current collecting portion 711, and the second end 714 is arranged away from the current collecting portion 711. At least part of the pole piece 7 also includes a reinforcement 75. The reinforcement 75 is arranged on the pole ear 712 and extends from the first end 713 toward the second end 714.

[0098] In the solution of the embodiment of the present application, the battery cell 3 includes a shell 4 and an electrode assembly 5, the electrode assembly 5 is accommodated in the shell 4, the electrode assembly 5 includes a pole piece 7, the pole piece 7 includes a current collector 71 and an active material layer 72, the current collector 71 includes a current collecting portion 711 and a pole ear 712 connected to each other, the active material layer 72 is arranged on the current collecting portion 711, the pole ear 712 includes a first end 713 and a second end 714 arranged opposite to each other, the first end 713 is connected to the current collecting portion 711, and the second end 714 is arranged away from the current collecting portion 711, at least part of the pole piece 7 also includes a reinforcement 75, the reinforcement 75 is arranged on the pole ear 712 and extends from the first end 713 toward the second end 714, and the reinforcement 75 is arranged to improve the strength of the pole ear 712 at the first end 713, so as to improve the problem of cracking of the pole ear 712 under the action of external force and improve the stability of the battery cell 3.

[0099] The tab 712 includes a first end 713 and a second end 714 that are oppositely disposed. In the extending direction of the tab 712 , the first end 713 of the tab 712 is disposed close to the current collecting portion 711 , and the second end 714 of the tab 712 is disposed away from the current collecting portion 711 .

[0100] During the production process of the battery cell 3, the tab 712 needs to be bent at the first end 713. Therefore, the reinforcement piece 75 is set at the first end 713 of the tab 712 and extends toward the second end 714. The reinforcement piece 75 improves the structural strength of the base of the tab 712 and reduces the risk of damage and cracking of the tab 712.

[0101] The specific extension size of the reinforcing member 75 can be designed by the user. The shape of the reinforcing member 75 can be designed by the user. For example, the reinforcing member 75 is in the shape of a disc, a strip, or a block.

[0102] Optionally, in the extension direction of the pole tab 712 , the reinforcing piece 75 covers the entire pole tab 712 , so as to better improve the strength of the pole tab 712 through the reinforcing piece 75 and reduce the risk of damage to the pole tab 712 .

[0103] Optionally, the reinforcing piece 75 is bonded to the surface of the tab 712 to improve the stability of the reinforcing piece 75 .

[0104] Optionally, the reinforcing member 75 is an insulating material block bonded to the tab 712 , illustratively, a rubber block, a silicone block, or an insulating foam block, etc.; or the reinforcing member 75 is an insulating adhesive layer coated on the surface of the tab 712 .

[0105] In some embodiments, as Figure 4 and Figure 5 As shown, the dielectric constant ε of the reinforcing member 75 satisfies ε≤5F / m.

[0106] In these embodiments, when the dielectric constant ε of the reinforcing member 75 satisfies the above conditions, the reinforcing member 75 has good insulation capability, so that the reinforcing member 75 can improve the problem of short circuit in the battery cell 3 caused by the inverted insertion of the tab 712 .

[0107] Optionally, the dielectric constant ε of the reinforcing member 75 is 1 F / m, 2.5 F / m, 3 F / m, 5 F / m, etc.

[0108] Optionally, the reinforcing member 75 is an insulating rubber layer. Exemplarily, the reinforcing member 75 may be made of polyvinyl alcohol, polyvinyl ketone, polymethacrylate, polyvinylidene fluoride, nano-silicone, polyacrylonitrile, polyacrylic acid, styrene-butadiene rubber, etc.

[0109] See also Figure 6 , Figure 6 It is a structural schematic diagram of a pole piece 7 of a battery cell 3 provided in another embodiment of the present application.

[0110] In some embodiments, as Figure 4 and Figure 6 As shown, at least two reinforcing members 75 are spaced apart on at least one side surface of the tab 712 in the thickness direction.

[0111] In these embodiments, at least two reinforcing members 75 are spaced apart on at least one side surface of the tab 712 in the thickness direction, so that while the reinforcing member 75 improves the strength of the tab 712 , the size of the reinforcing member 75 can be reduced, saving the material cost of the reinforcing member 75 , and reducing the impact of the reinforcing member 75 on the bending space of the tab 712 and the self-weight of the electrode assembly 5 , thereby reducing the processing difficulty of the battery cell 3 .

[0112] Optionally, one end of the reinforcing piece 75 is arranged on one side of the thickness direction of the pole lug 712, and the other end of the reinforcing piece 75 extends along a straight path, an inclined path, or a curved path in the extension direction of the pole lug 712.

[0113] For example, two, three, or five reinforcing members 75 are spaced apart on one side surface of the tab 712 in the thickness direction.

[0114] Optionally, the reinforcing members 75 on the same side surface in the thickness direction of the tab 712 have the same size to reduce the difficulty of processing the reinforcing members 75. Optionally, the reinforcing members 75 have the same shape to reduce the difficulty of processing the reinforcing members 75.

[0115] Optionally, a plurality of reinforcing members 75 are arranged at equal intervals to ensure that the force is evenly applied to all parts of the tab 712 .

[0116] See also Figure 7 , Figure 7 Schematic diagram of the structure of the pole piece 7 of the battery cell 3 provided in one embodiment of the present application.

[0117] In some embodiments, as Figure 4 、 Figure 5 and Figure 7 As shown, the reinforcing members 75 are disposed on both sides of the tab 712 in the thickness direction thereof.

[0118] In these embodiments, the reinforcing members 75 are disposed on both sides of the tab 712 in the thickness direction to enhance the supporting effect of the reinforcing members 75 on the surfaces on both sides of the tab 712 in the thickness direction, further reducing the risk of the tab 712 cracking under external force.

[0119] Optionally, the reinforcing pieces 75 on both sides of the tab 712 in the thickness direction may have the same or different sizes in the extending direction of the tab 712 .

[0120] Optionally, the two side surfaces of the tab 712 in the thickness direction are respectively the first surface and the second surface, and a number of reinforcing members 75 are arranged at intervals on the first surface and the second surface. The orthographic projection of the reinforcing member 75 arranged on the first surface in the thickness direction is located between two adjacent reinforcing members 75 arranged on the second surface, so that while reducing the overall size of the reinforcing member 75, all parts of the tab 712 in the width direction are in contact with the reinforcing member 75, so as to enhance the reinforcing effect of the reinforcing member 75 on the tab 712.

[0121] In some embodiments, as Figure 7 As shown, the thickness D1 of the active material layer 72 and the thickness D2 of the reinforcing member 75 satisfy D2 ≤ D1.

[0122] In these embodiments, when the thickness D1 of the active material layer 72 and the thickness D2 of the reinforcing member 75 meet the above conditions, the tabs 712 can be easily bent and folded together, and the thickness of the folded tabs 712 can be reduced, thereby improving the utilization of the space in the housing 4 .

[0123] Specifically, D1 is the thickness of the active material layer 72 after cold pressing.

[0124] Optionally, the thickness D2 of the reinforcing piece 75 satisfies 10 μm≤D2≤200 μm. For example, the thickness of the reinforcing piece 75 is 10 μm, 100 μm, or 200 μm.

[0125] In some embodiments, as Figure 4 and Figure 5 As shown, the surface of the tab 712 in the thickness direction includes a welding area 715 and a glue-coated area 716 that are connected to each other. The tabs 712 are connected to each other in the welding area 715 , and the reinforcing piece 75 is arranged in the glue-coated area 716 .

[0126] In these embodiments, the surface of the tab 712 in the thickness direction includes interconnected welding areas 715 and glue-coated areas 716. The tabs 712 are interconnected in the welding areas 715, and the reinforcement 75 is arranged in the glue-coated area 716. By arranging the reinforcement 75 and the welding area 715 at intervals, the problem of low welding strength and poor welding quality of the tab 712 in the subsequent welding stage of the tab 712 due to the invasion of the reinforcement 75 into the welding area 715 is improved.

[0127] The electrode assembly 5 includes multiple tabs 712, each of which is welded together at a welding area 715. The welding method can be ultrasonic welding. When the reinforcement 75 intrudes into the welding area 715, the welding area between adjacent electrode pieces 7 is reduced, and the welding strength may not meet the expected requirements.

[0128] The shape and size of the welding area 715 can be set arbitrarily. For example, the welding area 715 is circular or rectangular.

[0129] One end of the reinforcing piece 75 is disposed at the first end 713 of the tab 712, and the other end thereof extends in the adhesive coating area 716 toward the second end 714. Specifically, the reinforcing piece 75 covers the entire adhesive coating area 716, or the reinforcing piece 75 covers a portion of the adhesive coating area 716.

[0130] Optionally, the welding area 715 is provided in the middle area of ​​the tab 712 , and the glue-coated area 716 is provided around the welding area 715 , so as to allow a larger area of ​​the reinforcing piece 75 to be provided while ensuring reliable connection of the tab 712 .

[0131] In some embodiments, as Figure 4 and Figure 5 As shown, the reinforcement member 75 is disposed between the welding region 715 and the first end 713 .

[0132] In these embodiments, the reinforcement member 75 is arranged between the welding area 715 and the first end 713. While the reinforcement member 75 improves the strength of the pole tab 712, the difficulty of setting the reinforcement member 75 on the pole tab 712 is reduced, the material cost of the reinforcement member 75 is saved, the weight of the reinforcement member 75 is reduced, and the risk of the reinforcement member 75 invading the welding area 715 is reduced, thereby improving the reliability of the battery cell 3.

[0133] One end of the reinforcement 75 is arranged at the first end 713 of the pole lug 712 to enhance the structural strength of the pole lug 712 at the first end 713, that is, the root of the pole lug 712. The other end of the reinforcement 75 extends toward the welding area 715. The reinforcement 75 does not exceed the welding area 715 to reduce the processing difficulty of the reinforcement 75 and reduce the risk of the reinforcement 75 invading the welding area 715.

[0134] Optionally, the reinforcing piece 75 completely covers the area between the welding region 715 and the first end 713 to enhance the structural strength of the first end 713 of the tab 712 and reduce the risk of damage and cracking of the tab 712 .

[0135] In some embodiments, as Figure 4 and Figure 5 As shown, on one side surface of the tab 712 in its thickness direction, along the extension direction of the tab 712 , the surface area S1 between the first end 713 and the welding area 715 , and the surface area S2 of the reinforcement 75 satisfy 0.2*S1≤S2≤S1.

[0136] In these embodiments, when the surface area S1 of the tab 712 between the first end 713 and the welding area 715 and the surface area S2 of the reinforcement 75 meet the above conditions, it can be ensured that the size of the reinforcement 75 can be reduced while the reinforcement 75 can provide sufficient strength to the tab 712, thereby reducing the weight of the reinforcement 75, saving the material cost of the reinforcement 75, and improving the energy density of the battery cell 3.

[0137] Optionally, S1 = S2, and the structural strength of the tab 712 is improved by increasing the size of the reinforcing member 75, thereby reducing the risk of damage and cracking of the tab 712.

[0138] Optionally, the areas of the reinforcing member 75 on both side surfaces in the thickness direction of the tab 712 are the same or different.

[0139] See also Figure 8 and Figure 9 , Figure 8 1 is a schematic structural diagram of a pole piece 7 of a battery cell 3 provided in one embodiment of the present application; Figure 9 It is a partial structural diagram of the electrode assembly 5 of the battery cell 3 provided in one embodiment of the present application.

[0140] In some embodiments, as Figure 8 and Figure 9 As shown, the electrode sheet 7 includes a positive electrode sheet 73 and a negative electrode sheet 74, the positive electrode sheet 73 includes a positive current collector 731 and a positive active material layer 732, the positive current collector 731 includes a positive current collecting portion 7311 and a positive electrode ear 7312, and the positive electrode active material layer 732 is arranged on the positive current collecting portion 7311, the negative electrode sheet 74 includes a negative current collector 741 and a negative active material layer 742, the negative current collector 741 includes a negative current collecting portion 7411 and a negative electrode ear 7412, and the negative electrode active material layer 742 is arranged on the negative current collecting portion 7411, the positive current collecting portion 7311 includes a first portion 7313 and a second portion 7314, the second portion 7314 is arranged between the first portion 7313 and the electrode ear 712, the negative current collecting portion 7411 and the first portion 7313 are arranged correspondingly, and the reinforcement 75 extends to at least a portion of the surface of the positive electrode active material layer 732 of the second portion 7314.

[0141] In these embodiments, the positive current collecting portion 7311 includes a first part 7313 and a second part 7314, the second part 7314 is arranged between the first part 7313 and the tab 712, the negative current collecting portion 7411 and the first part 7313 are arranged correspondingly, and the reinforcement 75 extends to at least part of the surface of the positive electrode active material layer 732 of the second part 7314 to block the embedding of lithium ions in the electrolyte, so as to improve the problem of lithium deposition in the second part 7314 of the positive electrode sheet 73 caused by excessively high lithium ion concentration in the second part 7314.

[0142] The corresponding arrangement of the negative current collecting portion 7411 and the first portion 7313 means that the orthographic projection of the negative current collecting portion 7411 in the thickness direction of the electrode piece 7 coincides with the first portion 7313 .

[0143] The second portion 7314 is the overhang area of ​​the positive electrode sheet 73. This portion is provided to absorb machining errors in the positive current collector 731 and to reduce the risk of burrs on the edges of the positive current collector 7311 and the negative current collector 7411 being positioned opposite each other, potentially puncturing the separator and causing a short circuit in the electrode assembly 5. The specific dimensions of the second portion 7314 can be customized.

[0144] One end of the reinforcement 75 is arranged at the first end 713 of the pole ear 712, and the other end of the reinforcement 75 extends toward the second part 7314. The reinforcement 75 covers at least part of the positive electrode or material layer of the second part 7314. The reinforcement 75 is used to prevent lithium ions in the electrolyte from being embedded in the positive electrode active material layer 732 of the second part 7314, so as to improve the lithium deposition problem of the positive electrode sheet 73 in the second part 7314.

[0145] Optionally, the reinforcing piece 75 covers the entire surface of the positive electrode active material layer 732 of the second portion 7314 , further preventing lithium deposition of the positive electrode sheet 73 in the second portion 7314 .

[0146] See also Figure 10 , Figure 10 It is a partial structural diagram of the electrode assembly 5 of the pole piece 7 of the battery cell 3 provided in one embodiment of the present application.

[0147] In some embodiments, as Figure 4 and Figure 10 As shown, the electrode assembly 5 is formed by a plurality of pole pieces 7 stacked together, and along the stacking direction of the pole pieces 7, the reinforcement 75 is provided on at least one pole piece 7 at the end of the electrode assembly 5; or, the electrode assembly 5 is formed by winding the pole pieces 7, and the reinforcement 75 is provided on at least part of the pole piece 7 on the outside of the electrode assembly 5.

[0148] In these embodiments, in actual production, the outer pole piece 7 of the electrode assembly 5 is more easily damaged. Therefore, the reinforcement member 75 is arranged on the pole piece 7 at the end or the outer side of the electrode assembly 5 to enhance the strength of the pole ear 712 of the pole piece 7 at the end or the outer side of the electrode assembly 5, reduce the risk of damage to the pole ear 712, thereby improving the overall stability of the electrode assembly 5, saving the material cost of the reinforcement member 75, saving the internal space of the battery cell 3, improving the utilization rate of the internal space of the battery cell 3, and improving the energy density of the battery cell 3.

[0149] The electrode assembly 5 can be a laminated electrode assembly 5, which is composed of a plurality of stacked electrode sheets 7. A reinforcement 75 is provided on at least one electrode sheet 7 at the end of the electrode assembly 5. In this case, n electrode sheets 7 at one end of the electrode assembly 5 are provided with reinforcements 75, where 1≤n≤10. Since the end tabs 712 are more susceptible to damage and cracking, providing reinforcements 75 on the end tabs 712 can improve the overall reliability of the electrode assembly 5. Reinforcements 75 can be provided on the electrode sheets 7 at both ends of the electrode assembly 5. A maximum of 20 electrode sheets 7 in the electrode assembly 5 are provided with reinforcements 75 to address the problem of excessive encroachment of the reinforcements 75 on the internal space of the housing 4, resulting in low energy density of the battery cells 3.

[0150] Optionally, at both ends of the electrode assembly 5 , reinforcing pieces 75 are provided on the pole pieces 7 with the same number of layers.

[0151] The electrode assembly 5 may be a wound electrode assembly 5 formed by winding a pole piece 7. The reinforcing member 75 is provided on a portion of the tabs 712 of the pole piece 7, so that when the pole piece 7 is wound into the electrode assembly 5, the reinforcing member 75 is provided on a portion of the tabs 712 on the outside of the electrode assembly 5. Specifically, the reinforcing member 75 is provided on the m layers of tabs 712 on the outside of the electrode assembly 5, where 1≤m≤10. Since the outer tabs 712 are more susceptible to damage and cracking, providing the reinforcing member 75 on the outer tabs 712 can improve the overall reliability of the electrode assembly 5; and can also improve the problem of the reinforcing member 75 excessively encroaching on the internal space of the shell 4, resulting in too low an energy density of the battery cell 3.

[0152] Second, as Figure 4 and Figure 5 As shown, an embodiment of the present application provides a pole piece 7, which is applied to the battery cell 3 of the first embodiment mentioned above. The pole piece 7 includes a current collector 71 and an active material layer 72. The current collector 71 includes a current collecting portion 711 and a pole ear 712 connected to each other. The active material layer 72 is arranged on the current collecting portion 711. The pole ear 712 includes a first end 713 and a second end 714 arranged opposite to each other. The first end 713 is connected to the current collecting portion 711, and the second end 714 is arranged away from the current collecting portion 711. At least part of the pole piece 7 also includes a reinforcement 75, which is arranged on the pole ear 712 and extends from the first end 713 toward the second end 714.

[0153] In the solution of the embodiment of the present application, the reinforcement piece 75 is arranged on the pole tab 712 and extends from the first end 713 toward the second end 714. By providing the reinforcement piece 75 to improve the strength of the pole tab 712 at the first end 713, the problem of cracking of the pole tab 712 under the action of external force is improved, thereby improving the stability of the battery cell 3.

[0154] In some embodiments, as Figure 4 and Figure 6As shown, at least two reinforcing members 75 are spaced apart on at least one side surface of the tab 712 in the thickness direction.

[0155] In these embodiments, at least two reinforcing members 75 are spaced apart on at least one side surface of the tab 712 in the thickness direction, so that while the reinforcing member 75 improves the strength of the tab 712 , the size of the reinforcing member 75 can be reduced, saving the material cost of the reinforcing member 75 , and reducing the impact of the reinforcing member 75 on the bending space of the tab 712 and the self-weight of the electrode assembly 5 , thereby reducing the processing difficulty of the battery cell 3 .

[0156] In some embodiments, as Figure 5 and Figure 7 As shown, the reinforcing members 75 are disposed on both sides of the tab 712 in the thickness direction thereof.

[0157] In these embodiments, the reinforcing members 75 are disposed on both sides of the tab 712 in the thickness direction to enhance the supporting effect of the reinforcing members 75 on the surfaces on both sides of the tab 712 in the thickness direction, further reducing the risk of the tab 712 cracking under external force.

[0158] In some embodiments, as Figure 4 and Figure 5 As shown, the surface of the tab 712 in the thickness direction includes a welding area 715 and a glue-coated area 716 that are connected to each other. The tabs 712 are connected to each other in the welding area 715 , and the reinforcing piece 75 is arranged in the glue-coated area 716 .

[0159] In these embodiments, the surface of the tab 712 in the thickness direction includes interconnected welding areas 715 and glue-coated areas 716. The tabs 712 are interconnected in the welding areas 715, and the reinforcement 75 is arranged in the glue-coated area 716. By arranging the reinforcement 75 and the welding area 715 at intervals, the problem of low welding strength and poor welding quality of the tab 712 in the subsequent welding stage of the tab 712 due to the invasion of the reinforcement 75 into the welding area 715 is improved.

[0160] In a third aspect, an embodiment of the present application provides a battery device comprising the battery cell of the embodiment of the first aspect described above.

[0161] In a fourth aspect, an embodiment of the present application provides an electrical device, comprising the battery device of the embodiment of the third aspect described above.

[0162] In some embodiments, as Figures 1 to 10As shown, the battery cell 3 includes a shell 4 and an electrode assembly 5, the electrode assembly 5 is arranged in the shell 4, the electrode assembly 5 includes a pole piece 7, the pole piece 7 includes a positive pole piece 73 and a negative pole piece 74, the positive pole piece 73 includes a positive current collector 731 and a positive active material layer 732, the positive current collector 731 includes a positive current collecting portion 7311 and a positive electrode ear 7312, the positive active material layer 732 is arranged on the positive current collecting portion 7311, the negative pole piece 74 includes a negative current collector 741 and a negative active material layer 742, the negative current collector 741 includes a negative current collecting portion 7411 and a negative electrode ear 7412, the negative active material layer 742 is arranged on the negative current collecting portion 7411, the positive current collecting portion 7311 The electrode sheet 7 includes a first portion 7313 and a second portion 7314, wherein the second portion 7314 is disposed between the first portion 7313 and the electrode tab 712, the negative current collecting portion 7411 and the first portion 7313 are disposed correspondingly, and the electrode tab 712 includes a first end 713 and a second end 714 disposed opposite to each other, the first end 713 being connected to the current collecting portion 711, and the second end 714 being disposed away from the current collecting portion 711, wherein at least part of the electrode sheet 7 further includes a reinforcing member 75, the reinforcing member 75 being disposed on the electrode tab 712 and extending from the first end 713 toward the second end 714, and the reinforcing member 75 also extending to at least a portion of the surface of the positive electrode active material layer 732 of the second portion 7314;

[0163] At least two reinforcing members 75 are arranged at intervals on at least one side surface of the tab 712 in the thickness direction. The reinforcing members 75 are arranged on both sides of the tab 712 in the thickness direction. The surface of the tab 712 in the thickness direction includes interconnected welding areas 715 and glue-coated areas 716. Each tab 712 is interconnected in the welding area 715. The reinforcing member 75 is arranged between the welding area 715 and the first end 713. The tab 712 is on one side surface of the tab 712 in the thickness direction. The surface of the tab 712 between the first end 713 and the welding area 715 The surface area S1 of the active material layer 72 and the surface area S2 of the reinforcement 75 satisfy 0.2*S1≤S2≤S1, the thickness D1 of the active material layer 72 and the thickness D2 of the reinforcement 75 satisfy D2≤D1, the dielectric constant ε of the reinforcement 75 satisfies ε≤5F / m, the electrode assembly 5 is formed by stacking a plurality of pole pieces 7, and along the stacking direction of the pole pieces 7, the reinforcement 75 is provided on at least one pole piece 7 at the end of the electrode assembly 5; or, the electrode assembly 5 is formed by winding the pole pieces 7, and the reinforcement 75 is provided on at least part of the pole piece 7 on the outside of the electrode assembly 5.

[0164] In the solution of the embodiment of the present application, the battery cell 3 includes a shell 4 and an electrode assembly 5, the electrode assembly 5 is accommodated in the shell 4, the electrode assembly 5 includes a pole piece 7, the pole piece 7 includes a current collector 71 and an active material layer 72, the current collector 71 includes a current collecting portion 711 and a pole ear 712 connected to each other, the active material layer 72 is arranged on the current collecting portion 711, the pole ear 712 includes a first end 713 and a second end 714 arranged opposite to each other, the first end 713 is connected to the current collecting portion 711, and the second end 714 is arranged away from the current collecting portion 711, at least part of the pole piece 7 also includes a reinforcement 75, the reinforcement 75 is arranged on the pole ear 712 and extends from the first end 713 toward the second end 714, and the reinforcement 75 is arranged to improve the strength of the pole ear 712 at the first end 713, so as to improve the problem of cracking of the pole ear 712 under the action of external force and improve the stability of the battery cell 3.

[0165] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell, characterized in that: include: case; An electrode assembly is disposed in the housing, the electrode assembly comprising a pole piece, the pole piece comprising a current collector and an active material layer, the current collector comprising a current collecting portion and a pole tab connected to each other, the active material layer being disposed on the current collecting portion, the pole tab comprising a first end and a second end disposed oppositely, the first end being connected to the current collecting portion, and the second end being disposed away from the current collecting portion. Wherein, at least part of the pole pieces further include a reinforcing piece, and the reinforcing piece is arranged on the pole ear and extends from the first end toward the second end.

2. The battery cell according to claim 1, wherein: At least two reinforcing members are arranged at intervals on at least one side surface of the tab in the thickness direction.

3. The battery cell according to claim 1, wherein: The reinforcing pieces are arranged on both sides of the tab in the thickness direction thereof.

4. The battery cell according to any one of claims 1 to 3, characterized in that: The surface of the tab in the thickness direction includes a welding area and a glue coating area that are connected to each other. The tabs are connected to each other in the welding area, and the reinforcing piece is arranged in the glue coating area.

5. The battery cell according to claim 4, characterized in that The reinforcing member is disposed between the welding area and the first end.

6. The battery cell according to claim 5, characterized in that On one side surface of the tab in the thickness direction, along the extension direction of the tab, a surface area S1 between the first end and the welding region, and a surface area S2 of the reinforcing member satisfy 0.2*S1≤S2≤S1.

7. The battery cell according to claim 1, characterized in that The thickness D1 of the active material layer and the thickness D2 of the reinforcing member satisfy D2≤D1.

8. The battery cell according to claim 1, wherein: The dielectric constant ε of the reinforcing member satisfies ε≤5F / m.

9. The battery cell according to claim 1, characterized in that The electrode sheet includes a positive electrode sheet and a negative electrode sheet, the positive electrode sheet includes a positive current collector and a positive electrode active material layer, the positive current collector includes a positive current collector and a positive electrode ear, and the positive electrode active material layer is arranged on the positive current collector, the negative electrode sheet includes a negative current collector and a negative electrode active material layer, the negative current collector includes a negative current collector and a negative electrode ear, and the negative electrode active material layer is arranged on the negative current collector. The positive current collecting portion includes a first part and a second part, the second part is arranged between the first part and the electrode tab, the negative current collecting portion and the first part are arranged correspondingly, and the reinforcing member extends to at least a portion of the surface of the positive electrode active material layer of the second part.

10. The battery cell according to claim 1, characterized in that The electrode assembly is formed by stacking a plurality of electrode sheets, and the reinforcing member is provided on at least one electrode sheet at the end of the electrode assembly along the stacking direction of the electrode sheets; Alternatively, the electrode assembly is formed by winding the electrode sheets, and the reinforcing member is arranged on at least a portion of the electrode sheets outside the electrode assembly.

11. A pole piece, applied to the battery cell according to any one of claims 1 to 10, characterized in that: The electrode sheet includes a current collector and an active material layer. The current collector includes a current collecting portion and a tab connected to each other. The active material layer is provided on the current collecting portion. The tab includes a first end and a second end oppositely disposed. The first end is connected to the current collecting portion, and the second end is disposed away from the current collecting portion. Wherein, at least part of the pole pieces further include a reinforcing piece, and the reinforcing piece is arranged on the pole ear and extends from the first end toward the second end.

12. The pole piece according to claim 11, characterized in that: At least two reinforcing members are arranged at intervals on at least one side surface of the tab in the thickness direction.

13. The pole piece according to claim 11, characterized in that: The reinforcing pieces are arranged on both sides of the tab in the thickness direction thereof.

14. The pole piece according to any one of claims 11 to 13, characterized in that: The surface of the tab in the thickness direction includes a welding area and a glue coating area that are connected to each other. The tabs are connected to each other in the welding area, and the reinforcing piece is arranged in the glue coating area.

15. A battery device, characterized in that: The battery cell comprises the battery cell according to any one of claims 1 to 10.

16. An electrical device, characterized in that: A battery device comprising the battery device described in claim 15.

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