Battery monomer, battery device and electric device

Abstract

The utility model provides a battery monomer, a battery device and a power utilization device, and belongs to the technical field of batteries. The battery monomer comprises an electrode assembly, the electrode assembly comprises a cathode pole piece and an anode pole piece which are alternately stacked and a diaphragm located between the cathode pole piece and the anode pole piece, the anode pole piece and the diaphragm are of a continuous winding structure, and the cathode pole piece comprises an inner cathode pole piece and an outer cathode pole piece which is continuously wound along the periphery of the inner cathode pole piece. Wherein the electrode assembly comprises a plane area and bending areas, the bending areas are located at the two opposite ends of the plane area in the length direction of the electrode assembly, and the projection of the active material area of the inner cathode pole piece in the direction perpendicular to the plane area completely falls into the plane area. According to the electrode assembly, breakage of the inner cathode piece of the inner ring is reduced, the overall production efficiency is considered, and meanwhile the energy density is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a battery monomer, a battery device and a power utilization device. BACKGROUND

[0002] Energy saving and emission reduction is the key to the sustainable development of the automobile industry. Electric vehicles have become an important part of the sustainable development of the automobile industry due to their energy saving and environmental protection advantages. For electric vehicles, battery technology is an important factor for their development.

[0003] The battery device includes a battery monomer, the battery monomer includes an electrode assembly for generating an electrochemical reaction, the electrode assembly can be prepared by winding, and the electrode assembly includes an anode pole piece, a diaphragm and a cathode pole piece. For the wound electrode assembly, the electrode assembly usually needs to be flattened to adapt to the square shell, and the pole piece located in the inner circle is prone to cracking, thereby affecting the performance and service life of the battery. UTILITY MODEL CONTENT

[0004] The present application aims to at least solve one of the technical problems in the background art. To this end, one object of the present application is to provide a battery monomer, a battery device and a power utilization device to improve the problem of cracking of the pole piece located in the inner circle in the related art.

[0005] An embodiment of the first aspect of the present application provides a battery monomer, including an electrode assembly, the electrode assembly including cathode pole pieces and anode pole pieces alternately stacked, and a diaphragm located between the cathode pole pieces and the anode pole pieces, the anode pole pieces and the diaphragm being a continuous winding structure, the cathode pole pieces including an inner cathode pole piece, and an outer cathode pole piece continuously wound along the outer periphery of the inner cathode pole piece. Wherein, the electrode assembly includes a planar region and a bending region, the bending region being located at opposite ends of the planar region along the length direction of the electrode assembly, and the projection of the active material region of the inner cathode pole piece along the direction perpendicular to the planar region falls completely into the planar region.

[0006] In the technical solution of the embodiment of the present application, the active material region of the inner cathode pole piece located in the inner circle of the electrode assembly is avoided from the bending region, and the anode pole piece, the diaphragm and the outer cathode pole piece located in the outer circle of the electrode assembly are arranged as a continuous winding structure, thereby reducing the cracking of the inner cathode pole piece in the inner circle while improving the overall production efficiency and the energy density.

[0007] In some embodiments, in the planar region, the projection of the active material region of the inner cathode pole piece along the direction perpendicular to the planar region falls completely within the range of the active material region of the adjacent anode pole piece. Thereby, the space for lithium ion insertion on the active material region of the anode pole piece is increased, so that the lithium ions detached from the inner cathode pole piece can be fully inserted into the active material region of the anode pole piece, reducing the phenomenon of lithium precipitation.

[0008] In some embodiments, the inner cathode tab is in a continuous winding structure. Along the length direction of the inner cathode tab, the active material area and the blank area of the inner cathode tab are arranged alternately. The active material area is located in the planar area, and the blank area is located in the bending area. The blank area is the part of the inner cathode tab that is not coated with active material. In this way, the inner cathode tab in the continuous winding structure can not only improve the problem of easy breakage of the inner cathode tab, but also meet the production efficiency through winding.

[0009] In some embodiments, the inner cathode tab is in a laminated structure. By setting the inner cathode tab in the inner circle of the electrode assembly to be in a laminated structure, the breakage of the inner cathode tab in the inner circle is reduced, and the overall production efficiency is taken into account.

[0010] In some embodiments, the proportion of the number of layers of the inner cathode tab to the total number of layers of the cathode tab is greater than or equal to 10% and less than or equal to 20%. The total number of layers of the cathode tab is the sum of the number of layers of the inner cathode tab and the number of layers of the outer cathode tab. The number of layers of the outer cathode tab is the number of layers of the outer cathode tab in the direction perpendicular to the planar area. By setting the proportion of the number of layers of the inner cathode tab to be in a laminated structure to be within an appropriate range, the breakage of the inner cathode tab is reduced, the energy density is improved, and the production efficiency is taken into account.

[0011] In some embodiments, the number of layers of the inner cathode tab is greater than or equal to 2 and less than or equal to 10. By setting the number of layers of the inner cathode tab to be in a laminated structure to be within an appropriate range, the breakage of the inner cathode tab is reduced, the energy density is improved, and the production efficiency is taken into account.

[0012] In some embodiments, the part of each inner cathode tab located in the planar area has a first cathode tab extending in the height direction of the electrode assembly. This allows the cathode active material on each inner cathode tab to participate in the electrochemical reaction, which is beneficial to improving the efficiency of the battery cell.

[0013] In some embodiments, each of the multiple turns of the outer cathode tab formed by continuous winding is provided with a second cathode tab extending in the height direction of the electrode assembly. The projection of the second cathode tab and the first cathode tab in the direction perpendicular to the planar area at least partially overlaps. This facilitates the welding of the second cathode tab and the first cathode tab together.

[0014] In some embodiments, each of the multiple turns of the outer cathode tab formed by continuous winding is further provided with a third cathode tab extending in the height direction of the electrode assembly. The projection of the third cathode tab, the second cathode tab, and the first cathode tab in the direction perpendicular to the planar area at least partially overlaps. By adding the third cathode tab, the demand for allowing large current to pass under high charge and discharge rate can be met. At the same time, the projection overlap arrangement facilitates the welding of the third cathode tab, the second cathode tab, and the first cathode tab together.

[0015] In some embodiments, each of the multiple turns of the continuous winding of the anode tab is provided with a first anode lug extending along the height direction of the electrode assembly, and the projection of the first anode lug along the direction perpendicular to the planar region is completely staggered with the projection of the first cathode lug along the direction perpendicular to the planar region. The number of the anode lug is increased while the risk of short circuit caused by the contact between the first anode tab and the first cathode tab is reduced.

[0016] In some embodiments, each of the multiple turns of the continuous winding of the anode tab is further provided with a second anode lug extending along the height direction of the electrode assembly, and the projection of the second anode lug along the direction perpendicular to the planar region at least partially overlaps with the projection of the first anode lug along the direction perpendicular to the planar region. The second anode lug is added to meet the requirement of allowing large current to pass at high charge-discharge rate. Meanwhile, the projection overlap arrangement facilitates the welding of the second anode lug and the first anode lug.

[0017] In some embodiments, the first cathode lug is a full lug, each of the multiple turns of the continuous winding of the outer cathode tab is provided with a fourth cathode lug extending along a first direction, and each of the multiple turns of the continuous winding of the anode tab is provided with a third anode lug extending along a second direction opposite to the first direction. The first direction and the second direction are parallel to the height direction of the electrode assembly. The fourth cathode lug and the third anode lug are full lugs. The full lugs can increase the overcurrent area and improve the overcurrent capacity and charge-discharge performance of the battery.

[0018] Embodiments of the second aspect of the present application provide a battery device including the battery cell in the above embodiments.

[0019] Embodiments of the third aspect of the present application provide a power consuming device including the battery device in the above embodiments, and the battery device is used to provide electric energy.

[0020] The above description is only a summary of the technical solutions of the present application. In order to enable one skilled in the art to better understand the technical means of the present application, the above description can be implemented according to the content of the specification, and in order to make the above and other purposes, characteristics and advantages of the present application more obvious and easy to understand, the following specific embodiments of the present application are described. BRIEF DESCRIPTION OF DRAWINGS

[0021] In the drawings, like reference numerals refer to same or similar elements throughout the several views. The drawings are not necessarily to scale. It should be understood that the drawings only depict some embodiments in accordance with the present disclosure and should not be considered as limiting the scope of the present application.

[0022] Figure 1 Structure schematic diagram of a vehicle of some embodiments of the present application;

[0023] Figure 2 Exploded view of a battery device according to some embodiments of the present application;

[0024] Figure 3 Exploded view of a battery cell according to some embodiments of the present application;

[0025] Figure 4 Structure view of an electrode assembly according to some embodiments of the present application;

[0026] Figure 5 Structure view of an inner circle of an electrode assembly according to some embodiments of the present application;

[0027] Figure 6 Structure view of an outer circle of an electrode assembly according to some embodiments of the present application;

[0028] Figure 7 Structure view of an electrode assembly according to some embodiments of the present application;

[0029] Figure 8 Structure view of an electrode assembly according to some embodiments of the present application.

[0030] BRIEF DESCRIPTION OF DRAWINGS

[0031] 1000, vehicle;

[0032] 100, battery device; 200, controller; 300, motor;

[0033] 10, case; 11, first portion; 12, second portion;

[0034] 20, battery cell; 21, end cap; 21a, electrode terminal; 22, case; 23, electrode assembly;

[0035] 231, cathode tab; 2311, inner cathode tab; 2312, outer cathode tab; 231a, first cathode tab; 231b, second cathode tab; 231c, third cathode tab; 231d, fourth cathode tab;

[0036] 232, anode tab; 232a, first anode tab; 232b, second anode tab; 232c, third anode tab;

[0037] 233, separator;

[0038] 234, flat area;

[0039] 235, bent area;

[0040] X, thickness direction; Y, length direction; Z, height direction; F1, first direction; F2, second direction. DETAILED DESCRIPTION

[0041] The embodiments of the present application will be described in detail below with reference to the drawings. The following examples are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, and cannot be used to limit the protection scope of the present application.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application; the terms "comprising," "comprises" and "including" as used herein are synonymous with and meant to have the same meaning as the term "including"; the term "coupled" as used herein means the joining of two members together with one or more intervening members.

[0043] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0044] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearance of the phrase in various places in the specification does not necessarily all refer to the same embodiment, nor is it necessarily independent or alternative embodiments to each other. The skilled person in the art explicitly and implicitly understands that the embodiments described herein can be combined with other embodiments.

[0045] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in this paper generally represents that the front and rear associated objects are a "or" relationship.

[0046] In the description of the embodiments of the present application, the term "a plurality of" refers to two or more (including two), and similarly, "a plurality of groups" refers to two or more groups (including two groups), and "a plurality of pieces" refers to two or more pieces (including two pieces).

[0047] In the description of the embodiments of the present application, the orientations or positional relationships indicated by the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientations or positional relationships shown in the drawings, and 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 devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0048] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the technical terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, can be fixedly connected, or can be detachably connected, or can be integrated; can be mechanically connected, or can be electrically connected; can be directly connected, or can be indirectly connected through an intermediate medium, or can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0049] At present, from the development of market situation, the application of battery is more and more extensive. The battery is not only applied to the energy storage power supply system of hydropower, thermal power, wind power and solar power station, but also widely used in electric bicycles, electric motorcycles, electric vehicles and other electric vehicles, and aerospace and other fields. With the continuous expansion of the application field of battery, the market demand is also increasing.

[0050] The battery device includes a battery monomer, the battery monomer includes an electrode assembly for generating an electrochemical reaction, the electrode assembly can be prepared by winding, and the electrode assembly includes an anode sheet, a separator and a cathode sheet. With the development of battery technology, in order to continuously improve the energy density of the battery monomer, the active material layer and the thickness of the sheet in the electrode assembly are gradually increased. In the electrode assembly obtained by winding, compared with the sheet located at the outer circle, the sheet located at the inner circle has a smaller radius and a larger bending degree, and is prone to uneven deformation or even cracks after being flattened, thereby affecting the performance and service life of the battery.

[0051] Based on the above considerations, the application provides a battery monomer, a battery device and a power consumption device. The battery monomer comprises an electrode assembly, the electrode assembly comprises cathode pole pieces and anode pole pieces which are alternately stacked, and a diaphragm between the cathode pole pieces and the anode pole pieces, the anode pole pieces and the diaphragm are in a continuous winding structure, the cathode pole pieces comprise inner cathode pole pieces, and outer cathode pole pieces which are continuously wound along the outer periphery of the inner cathode pole pieces. Wherein, the electrode assembly comprises a planar area and a bending area, the bending area is located at the opposite ends of the planar area along the length direction of the electrode assembly, and the projection of the active material area of the inner cathode pole pieces along the direction perpendicular to the planar area completely falls into the planar area.

[0052] By avoiding the active material area of the inner cathode pole pieces in the inner circle of the electrode assembly from the bending area, and setting the anode pole pieces, the diaphragm and the outer cathode pole pieces in the outer circle of the electrode assembly as a continuous winding structure, the fracture of the inner cathode pole pieces in the inner circle is reduced, the overall production efficiency is considered, and the energy density is improved.

[0053] The battery monomer disclosed in the embodiments of the application can be used in a power consumption device such as a vehicle, a ship or an aircraft, but is not limited to this. The power supply system of the power consumption device can be composed of the battery monomer, the battery device and the like disclosed in the application. In this way, the fracture of the inner cathode pole pieces in the inner circle is reduced, the overall production efficiency is considered, and the energy density is improved.

[0054] The embodiments of the application provide a power consumption device using a battery device as a power supply. The power consumption device can be, but is not limited to, a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, an electric vehicle, an electric car, a ship, a spacecraft and the like. The electric toy can include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy and an electric aircraft toy, and the spacecraft can include an airplane, a rocket, a space shuttle and a spacecraft.

[0055] The following embodiments are described for convenience with a power consumption device as a vehicle 1000 in an embodiment of the application as an example.

[0056] Please refer to Figure 1 , Figure 1A structural schematic diagram of a vehicle is provided for some embodiments of the present application. The vehicle 1000 can be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid vehicle or a range extended vehicle, etc. The vehicle 1000 is internally provided with a battery device 100, which can be arranged at the bottom, head or tail of the vehicle 1000. The battery device 100 can be used for power supply of the vehicle 1000, for example, the battery device 100 can be used as the operating power supply of the vehicle 1000. The vehicle 1000 can further include a controller 200 and a motor 300, and the controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, to meet the power demand of the vehicle 1000 during starting, navigation and driving.

[0057] In some embodiments of the present application, the battery device 100 can not only be used as the operating power supply of the vehicle 1000, but also be used as the driving power supply of the vehicle 1000, to replace or partially replace fuel or natural gas to provide driving power for the vehicle 1000.

[0058] Please refer to Figure 2 , Figure 2 A disassembled structural schematic diagram of a battery device is provided for some embodiments of the present application. The battery device 100 includes a box body 10 and a battery cell 20, and the battery cell 20 is contained in the box body 10. Among them, the box body 10 is used to provide a containing space for the battery cell 20, and the box body 10 can adopt various structures. In some embodiments, the box body 10 can include a first part 11 and a second part 12, and the first part 11 and the second part 12 are mutually covered. The first part 11 and the second part 12 jointly define a containing space for containing the battery cell 20. The second part 12 can be a hollow structure with one end open, and the first part 11 can be a plate structure, which is covered on the open side of the second part 12 to jointly define the containing space with the second part 12; the first part 11 and the second part 12 can also be hollow structures with one side open, and the open side of the first part 11 is covered on the open side of the second part 12. Of course, the box body 10 formed by the first part 11 and the second part 12 can have various shapes, such as a cylinder, a cuboid, etc.

[0059] In the battery device 100, the battery cells 20 can be multiple, and the multiple battery cells 20 can be connected in series, in parallel, or in a mixed connection, where the mixed connection means that the multiple battery cells 20 are connected in series and in parallel. The multiple battery cells 20 can be directly connected in series, in parallel, or in a mixed connection, and the whole of the multiple battery cells 20 can be accommodated in the case 10. Of course, the battery device 100 can also be in a form in which the multiple battery cells 20 are first connected in series, in parallel, or in a mixed connection to form a battery module, and the multiple battery modules are connected in series, in parallel, or in a mixed connection to form a whole, and the whole is accommodated in the case 10. The battery device 100 can further include other structures, for example, the battery device 100 can further include a current collecting member for electrically connecting the multiple battery cells 20.

[0060] Each of the battery cells 20 can be a secondary battery or a primary battery, and can be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 20 can have a cylindrical shape, a flat shape, a cuboid shape, or other shapes.

[0061] The battery cell 20 refers to the smallest unit constituting the battery device 100. For example, the battery cell 20 includes an end cap 21, a case 22, an electrode assembly 23, and other functional components. Figure 3 The battery cell 20 includes an end cap 21, a case 22, an electrode assembly 23, and other functional components.

[0062] The electrode assembly 23 is a component in which an electrochemical reaction occurs in the battery cell 20. The case 22 can include one or more electrode assemblies 23. The electrode assembly 23 is mainly formed by winding or stacking an anode sheet and a cathode sheet, and a separator is generally disposed between the anode sheet and the cathode sheet. The anode sheet and the cathode sheet have portions of active materials constituting a main body of the electrode assembly, and portions of the anode sheet and the cathode sheet not having the active materials each constitute a tab. The anode tab and the cathode tab can be located together at one end of the main body or can be located at both ends of the main body, respectively. In the charging and discharging process of the battery, the anode active material and the cathode active material react with an electrolyte, and the tabs are connected to an electrode terminal to form a current loop.

[0063] Referring to FIGS. 1 to 3, the battery device 100 according to an embodiment of the disclosure includes a case 10, a battery module 20, and a terminal 30. Figures 4 to 6 FIG. 4 is a schematic view of an electrode assembly according to an embodiment of the disclosure, Figure 4 FIG. 5 is a schematic view of an inner circle structure of an electrode assembly according to an embodiment of the disclosure, Figure 5 FIG. 6 is a schematic view of an outer circle structure of an electrode assembly according to an embodiment of the disclosure. Figure 6 FIG. 7 is a schematic view of an electrode assembly according to another embodiment of the disclosure.

[0064] The embodiment of the present application provides a battery monomer 20, which comprises an electrode assembly 23, the electrode assembly 23 comprises cathode pole pieces 231 and anode pole pieces 232 which are alternately stacked, and a diaphragm 233 between the cathode pole pieces 231 and the anode pole pieces 232, the anode pole pieces 232 and the diaphragm 233 are in a continuous winding structure, the cathode pole pieces 231 comprise inner cathode pole pieces 2311 and outer cathode pole pieces 2312 which are continuously wound along the outer periphery of the inner cathode pole pieces 2311. Wherein, the electrode assembly 23 comprises a planar area 234 and a bending area 235, the bending area 235 is located at opposite ends of the planar area 234 along the length direction Y of the electrode assembly 23, and the projection of the active material area of the inner cathode pole pieces 2311 in the direction perpendicular to the planar area 234 completely falls into the planar area 234.

[0065] The electrode assembly 23 is a component in the battery monomer 20 where an electrochemical reaction occurs. The cathode pole pieces 231 comprise a cathode current collector, the part of the cathode current collector coated with cathode active material forms the active material area of the cathode pole pieces 231, and the part of the cathode current collector without coating of the cathode active material forms the tab of the cathode pole pieces 231. The anode pole pieces 232 comprise an anode current collector, the part of the anode current collector coated with anode active material forms the active material area of the anode pole pieces 232, and the part of the anode current collector without coating of the anode active material forms the tab of the anode pole pieces 232. The anode current collector and the cathode current collector can be metal foils.

[0066] The diaphragm 233 is located between adjacent cathode pole pieces 231 and anode pole pieces 232, the diaphragm 233 can be PP or PE material, the diaphragm 233 has electronic insulation, so that the cathode pole pieces 231 and the anode pole pieces 232 are isolated, and the diaphragm 233 has a certain porosity, so that the diaphragm 233 has lower resistance and higher ionic conductivity.

[0067] The anode pole pieces 232 and the diaphragm 233 are in a continuous winding structure, so that the winding mode of the anode pole pieces 232 and the diaphragm 233 is not cut off in continuous winding, and the winding mode can be specifically that the starting end of the anode pole pieces 232 and the diaphragm 233 is fixed on a winding needle, that is, the starting end of the anode pole pieces 232 and the diaphragm 233 is located at the position of the winding center, with the rotation of the winding needle, the number of turns of the anode pole pieces 232 and the diaphragm 233 gradually increases, and the whole forms a structure with an inner turn and an outer turn. The inner turn and the outer turn are relative concepts, the inner turn is located in the outer turn, and the inner turn is a position closer to the winding center relative to the outer turn.

[0068] The outer cathode tab 2312 is continuously wound along the outer periphery of the inner cathode tab 2311, and thus the inner cathode tab 2311 is located in the inner circle relative to the outer cathode tab 2312, and the outer cathode tab 2312 is located in the outer circle relative to the inner cathode tab 2311. The inner cathode tab 2311 located in the inner circle can be in a continuous winding structure, a laminated structure, or a partial continuous winding structure and a partial laminated structure. The laminated structure refers to a structure in which a plurality of independent inner cathode tabs 2311 are stacked along the thickness direction.

[0069] In some embodiments, the inner cathode tab is in a continuous winding structure, and a plurality of active material regions are arranged at intervals along the length direction of the inner cathode tab, and a blank region is arranged between two adjacent active material regions. The blank region refers to a region without active material, i.e., the inner cathode tab is obtained by coating the foil at intervals. The blank region is only the foil, and the thickness of the blank region is smaller than that of the active material region. Thus, when the inner cathode tab is wound together with the anode tab 232 and the separator 233, the blank region can be arranged corresponding to the bending region 235, and the active material region corresponds to the flat region 234.

[0070] In other embodiments, the inner cathode tab 2311 is in a laminated structure, and the laminated manner of the inner cathode tab 2311 located in the inner circle can be that the inner cathode tab 2311 is arranged between the upper and lower layers of the anode tab 232 and the separator 233 during winding, and thus the inner cathode tab 2311 is arranged between each layer. Correspondingly, the number of inner cathode tabs 2311 is multiple, and the multiple inner cathode tabs 2311 form a laminated structure. Overall, the complete layer of the anode tab 232 includes two layers, and the two layers are located on the opposite sides of the winding center. Thus, two inner cathode tabs can be arranged during each winding of the anode tab 232, and the two inner cathode tabs 2311 are located on the opposite sides of the winding center, so that the two layers of the anode tab 232 in each layer have a cathode tab 231 adjacent thereto, thereby forming the alternating laminated cathode tab 231 and anode tab 232.

[0071] The outer cathode tab 2312 located in the outer circle is in a continuous winding structure, and thus the outer cathode tab 2312, the anode tab 232, and the separator 233 can be wound together after the continuous winding or laminating of the inner cathode tab 2311 in the inner circle is completed.

[0072] The electrode assembly 23 includes the flat area 234 and the bending area 235, and the electrode assembly 23 as a whole is a flat body with a certain thickness. The flat area 234 is parallel to the length direction Y of the electrode assembly, and the direction perpendicular to the flat area 234 is the thickness direction X. The flat body can be formed by applying pressure to the electrode assembly 23 along the thickness direction X, and the electrode assembly 23 is flattened along the thickness direction X. The force receiving part of the electrode assembly 23 corresponds to the flat area 234, and the size of the electrode assembly 23 along the thickness direction X gradually decreases, while the bending degree of the bending area 235 located at the opposite ends of the flat area 234 along the length direction Y further increases. Taking a complete winding of the anode tab 232 as an example, the complete winding of the anode tab 232 includes two oppositely arranged flat areas 234 and two oppositely arranged bending areas 235. The flat area 234 is perpendicular to the thickness direction X, one end of the two flat areas 234 is connected through one of the bending areas 235, and the other end of the two flat areas 234 is connected through the other bending area 235. Similarly, the complete winding of the outer cathode tab 2312 also includes two flat areas 234 and two bending areas 235, and the arrangement structure is the same as that of the complete winding of the anode tab 232, which will not be described here. The bending area 235 has a certain curvature due to bending, and the flat area 234 has almost no bending, so the deformation amount of the bending area 235 is greater than that of the flat area 234.

[0073] In the multi-coil structure formed by winding, the radius of the bending area 235 located in the inner coil is smaller than the radius of the bending area 235 located in the outer coil, and accordingly, the bending degree of the bending area 235 located in the inner coil is larger, and the deformation amount is larger. The projection of the active material area of the inner cathode tab 2311 along the thickness direction X can completely fall into the planar area, and it can be understood that along the thickness direction X, the active material area of the inner cathode tab 2311 is arranged in parallel with the planar area 234, and the active material area of the inner cathode tab 2311 does not exceed the planar area 234, that is, the arrangement position of the active material area of the inner cathode tab 2311 completely avoids the bending area 235, as described above, the planar area 234 has little bending, and the active material area of the inner cathode tab 2311 arranged in the planar area 234 also has little bending, thereby reducing the deformation of the inner cathode tab 2311, and further reducing the breaking phenomenon caused by the deformation. It should be noted that for the inner cathode tab in the above embodiment, the blank area corresponds to the bending area 235, the blank area is not coated with active material, and the blank area is only a foil and has a small thickness, that is, the blank area has good toughness and can withstand the deformation of the bending area 235 located in the inner coil without breaking. Thus, the inner cathode tab 2311 of the present application improves the problem that the cathode tab is prone to breaking due to the large deformation of the inner coil in the winding structure, and can meet the application requirements of the cathode tab with small toughness and large brittleness, thereby improving the reliability and service life of the battery cell 20.

[0074] With the increase of the winding number, the radius of the bending area 235 located in the outer coil gradually increases, the bending degree gradually decreases, and accordingly, the deformation amount is also small. The deformation amount is within the range that the outer cathode tab 2312 can withstand without breaking, and therefore, after the inner cathode tab 2311 reaches a certain number of layers, the outer cathode tab 2312 can be wound together with the anode tab 232 and the separator 233 to form an outer coil. At this time, the active material area of the outer cathode tab 2312 in the continuous winding structure falls into both the planar area 234 and the bending area 235, that is, the anode tab 232 located in the bending area 235 also has the outer cathode tab 2312 corresponding thereto, thereby increasing the area of the active material area on the outer cathode tab 2312, and improving the energy density.

[0075] Compared with the continuous winding process, the production efficiency of the stacking process is lower. For the inner cathode tab 2311 in the stacking structure, the inner cathode tab 2311 in the inner coil is stacked, and the outer cathode tab 2312 in the outer coil is continuously wound. Compared with the entire electrode assembly being in the stacking structure, the present application can not only reduce the breaking of the inner cathode tab 2311 in the inner coil, but also take into account the overall production efficiency.

[0076] Furthermore, the continuously wound anode electrode 232, diaphragm 233, and outer cathode electrode 2312 have a structure where the next turn is close to the previous turn, minimizing the gap as much as possible. For the electrode assembly 23 as a whole, this makes full use of the internal space of the electrode assembly 23, reducing space waste. This allows the space inside the electrode assembly 23 to be used to effectively arrange the cathode electrode 231 and anode electrode 232, thereby improving the energy density.

[0077] By avoiding the bending region 235 in the active material region of the inner cathode electrode 2311 located in the inner ring of the electrode assembly, and by setting the anode electrode 232, the diaphragm 233 and the outer cathode electrode 2312 located in the outer ring of the electrode assembly as a continuous winding structure, the breakage of the inner cathode electrode 2311 in the inner ring is reduced, and the energy density is improved while taking into account the overall production efficiency.

[0078] like Figure 4 and Figure 5 As shown, according to some embodiments of this application, in the planar region 234, the projection of the active material region of the inner cathode electrode 2311 along a direction perpendicular to the planar region 234 completely falls within the range of the active material region of the adjacent anode electrode 232.

[0079] The direction perpendicular to the plane region 234 is the thickness direction X. The projection of the active material region of the inner cathode electrode 2311 along the thickness direction X completely falls within the range of the active material region of the adjacent anode electrode 232. It can be understood that the active material region of the inner cathode electrode 2311 can be completely covered by the active material region of the anode electrode 232, that is, the active material region of the anode electrode 232 completely covers the active material region of the inner cathode electrode 2311, so as to reduce the phenomenon of lithium plating.

[0080] In some examples, along the length direction Y, the size of the active material region of the anode electrode 232 is larger than the size of the active material region of the inner cathode electrode 2311. Correspondingly, the area of ​​the active material region of the anode electrode 232 is larger than the area of ​​the active material region of the inner cathode electrode 2311, thereby achieving complete coverage of the active material region of the inner cathode electrode 2311 by the active material region of the anode electrode 232.

[0081] Taking a single lithium-ion battery cell as an example, the causes of lithium plating are explained. During charging, lithium ions are released from the cathode and embedded in the anode. However, if there is insufficient space on the anode for these lithium ions to embed, they can only gain electrons on the surface of the anode, forming metallic lithium, thus leading to lithium plating. Lithium plating not only degrades the performance of the lithium-ion battery cell and shortens its cycle life, but also limits its fast-charging capacity. In severe cases, the released lithium ions can form lithium crystals on the anode surface, which can easily puncture the separator, causing a short circuit between adjacent cathode and anode cells.

[0082] By completely covering the active material region of the inner cathode electrode 2311 with the active material region of the anode electrode 232, the space for lithium ion insertion on the active material region of the anode electrode 232 is increased, so that lithium ions extracted from the inner cathode electrode 2311 can be fully inserted into the active material region of the anode electrode 232, reducing lithium plating and improving the reliability and service life of the battery cell 20.

[0083] According to some embodiments of this application, the inner cathode electrode has a continuously wound structure. Along the length of the inner cathode electrode, the active material region and the blank region are arranged alternately. The active material region is located in the planar region, and the blank region is located in the bending region. The blank region is the part of the inner cathode electrode that is not coated with active material.

[0084] The blank area is the part of the inner cathode electrode that is not coated with active material. That is, the blank area is only foil. The thickness of the blank area is smaller than that of the active material area. The blank area has good toughness and can withstand the deformation of the bending area located in the inner ring without breaking. Therefore, the inner cathode electrode is wound together with the anode electrode 232 and the diaphragm 233, which can not only improve the problem of easy breakage of the inner cathode electrode, but also meet a certain production efficiency through the winding method.

[0085] By setting up an inner cathode electrode with alternating active material areas and blank areas, the continuously wound inner cathode electrode can not only improve the problem of easy breakage of the inner cathode electrode, but also meet a certain production efficiency through the winding method.

[0086] like Figure 4 and Figure 5 As shown, according to some embodiments of this application, the inner cathode electrode 2311 has a stacked structure.

[0087] The laminated structure refers to a structure in which a plurality of inner cathode electrode pieces 2311 independent of each other are stacked along the thickness direction. When the inner cathode electrode pieces 2311 are in the laminated structure, the laminated manner of the inner cathode electrode pieces 2311 located in the inner circle can be that, while the anode electrode piece 232 and the separator 233 are being wound, the inner cathode electrode piece 2311 is placed between the last winding circle and the next winding circle, that is, the inner cathode electrode piece 2311 is placed between every two winding circles, and correspondingly, the number of the inner cathode electrode pieces 2311 is multiple, and the multiple inner cathode electrode pieces 2311 form the laminated structure. Overall, a complete circle of the anode electrode piece 232 wound includes two layers of structures, and the two layers of structures are located on opposite sides of the winding center, so that when the inner cathode electrode pieces 2311 are laminated, two inner cathode electrode pieces can be placed for every winding circle of the anode electrode piece 232, and the two inner cathode electrode pieces 2311 are located on opposite sides of the winding center, respectively, so that the two layers of anode electrode pieces 232 on each circle have a cathode electrode piece 231 adjacent thereto, thereby forming the alternating laminated cathode electrode piece 231 and anode electrode piece 232.

[0088] Compared with the continuously wound inner cathode electrode piece, the inner cathode electrode piece 2311 in the laminated structure does not need to be provided with an active material area to completely avoid the bending area 235, thereby reducing the difficulty of coating the active material area and improving the efficiency of preparing the inner cathode electrode piece.

[0089] By arranging the inner cathode electrode piece 2311 in the inner circle of the electrode assembly in the laminated structure, the breaking of the inner cathode electrode piece 2311 in the inner circle is reduced, and the overall production efficiency is considered.

[0090] According to some embodiments of the present application, the number of layers of the inner cathode electrode piece 2311 accounts for greater than or equal to 10% and less than or equal to 20% of the total number of layers of the cathode electrode piece 231. The total number of layers of the cathode electrode piece 231 is the sum of the number of layers of the inner cathode electrode piece 2311 and the number of layers of the outer cathode electrode piece 2312, and the number of layers of the outer cathode electrode piece 2312 is the number of layers of the outer cathode electrode piece 2312 along the direction perpendicular to the planar area 234.

[0091] The inner cathode electrode piece 2311 is in the laminated structure, and each layer of the laminated structure is an inner cathode electrode piece 2311, so the number of layers of the inner cathode electrode piece 2311 is the number of inner cathode electrode pieces 2311 in the laminated structure.

[0092] The outer cathode electrode piece 2312 is in the continuously wound structure, and the number of layers of each circle of the continuously wound structure is two, that is, the number of layers of the outer cathode electrode piece 2312 is twice the number of winding circles of the outer cathode electrode piece 2312. In one example, the number of winding circles of the outer cathode electrode piece 2312 is 30, and the number of layers of the outer cathode electrode piece 2312 is 60. In another example, the number of winding circles of the outer cathode electrode piece 2312 is 30.5, and the number of layers of the outer cathode electrode piece 2312 is 61.

[0093] The proportion of the number of layers of the inner cathode tab 2311 can be 10%, 13%, 15%, 18%, or 20%, or any value between the adjacent two values.

[0094] By setting the proportion of the number of layers of the inner cathode tab 2311 within an appropriate range, the phenomenon of the inner cathode tab 2311 breaking is reduced, the energy density is improved, and the production efficiency is also taken into account.

[0095] As shown in FIG. 13, according to some embodiments of the present application, the number of layers of the inner cathode tab 2311 is greater than or equal to 2 and less than or equal to 10. Figure 5

[0096] The number of layers of the inner cathode tab 2311 can be 2, 3, 4, 5, 6, 7, 8, 9, or 10. In some embodiments, the number of layers of the inner cathode tab 2311 is 4. Figure 5 As shown in FIG. 13, according to some embodiments of the present application, the number of layers of the inner cathode tab 2311 is greater than or equal to 2 and less than or equal to 10.

[0097] By appropriately stacking a certain number of layers of the inner cathode tab 2311 and avoiding the bending area 235 of the inner cathode tab 2311, the problem of the cathode tab being easily broken due to a large deformation of the inner circle in the winding structure is overcome. As the anode tab 232 and the separator 233 are wound, when the number of layers of the inner cathode tab 2311 reaches a certain number, it indicates that the anode tab 232 and the separator 233 have been wound for a large number of turns, and then the deformation of the bending area 235 on the outer circle is reduced. The deformation is within the range that the cathode tab can withstand without breaking, and subsequent production does not need to continue the stacking operation of the inner cathode tab 2311 with low production efficiency. Therefore, after the inner cathode tab 2311 reaches a certain number of layers, the outer cathode tab 2312 can be wound together with the anode tab 232 and the separator 233 to form an outer circle. At this time, the outer cathode tab 2312 in the continuous winding structure increases the area of the active material area on the outer cathode tab 2312, thereby improving the energy density. At the same time, the outer cathode tab 2312 is wound together with the anode tab 232 and the separator 233, which also improves the overall production efficiency.

[0098] By setting the proportion of the number of layers of the inner cathode tab 2311 within an appropriate range, the phenomenon of the inner cathode tab 2311 breaking is reduced, the energy density is improved, and the production efficiency is also taken into account.

[0099] As shown in FIG. 13, according to some embodiments of the present application, the number of layers of the inner cathode tab 2311 is greater than or equal to 2 and less than or equal to 10. Figures 4 to 7 Figure 7 FIG. 14 is a structure diagram of an electrode assembly according to some embodiments of the present application. According to some embodiments of the present application, each inner cathode tab 2311 has a first cathode tab 231a extending in the height direction Z of the electrode assembly 23.

[0100] ​​Each inner cathode electrode 2311 has a first cathode tab 231a. It can be understood that in the stacked inner cathode electrode 2311, each layer of the stacked structure has a first cathode tab 231a. The height direction Z of the electrode assembly 23 is the direction of the axis of the outer cathode electrode 2312. The height direction Z, length direction Y, and thickness direction X of the electrode assembly 23 are perpendicular to each other.

[0101] For the inner cathode electrode 2311, the active material region of the inner cathode electrode 2311 is formed in the part of the foil where the cathode active material is coated, and the first cathode tab 231a extending along the height direction Z of the electrode assembly 23 is formed in the part of the foil where the active material is not coated.

[0102] In some embodiments, the projections of the first cathode tabs 231a on each inner cathode tab 2311 along the thickness direction X at least partially overlap, so as to facilitate welding all the first cathode tabs 231a together.

[0103] By providing a first cathode tab 231a on each inner cathode electrode 2311, each inner cathode electrode 2311 can be connected to the electrode terminal through the first cathode tab 231a to form a current loop. That is, the cathode active material on each inner cathode electrode 2311 can participate in the electrochemical reaction, which is beneficial to improving the efficiency of the battery cell 20.

[0104] like Figures 4 to 7 As shown, according to some embodiments of this application, each turn of the multi-turn structure formed by the continuous winding of the outer cathode electrode 2312 is provided with a second cathode tab 231b extending along the height direction Z of the electrode assembly 23, and the projection of the second cathode tab 231b and the first cathode tab 231a along the thickness direction X at least partially overlaps.

[0105] For the external cathode electrode 2312, the active material region of the external cathode electrode 2312 is formed in the part of the foil where the cathode active material is coated, and the second cathode tab 231b extending along the height direction Z of the electrode assembly 23 is formed in the part of the foil where the active material is not coated.

[0106] The projections of the second cathode tab 231b and the first cathode tab 231a along the thickness direction X at least partially overlap. It can be understood that the projections of the second cathode tab 231b and the first cathode tab 231a intersect, or the second cathode tab 231b and the first cathode tab 231a are the same size and their edges are aligned, thereby facilitating the welding of the second cathode tab 231b and the first cathode tab 231a together.

[0107] By arranging the second cathode tab 231b in an overlapping manner with the first cathode tab 231a, the second cathode tab 231b and the first cathode tab 231a are facilitated to be welded together, so as to connect the inner cathode tab 2311 and the outer cathode tab 2312 as a whole.

[0108] As shown in FIG. 1, according to some embodiments of the present application, each of the multiple turns of the outer cathode tab 2312 continuously wound forms is further provided with a third cathode tab 231c extending along the height direction Z of the electrode assembly 23, and the projections of the third cathode tab 231c, the second cathode tab 231b and the first cathode tab 231a along the direction perpendicular to the planar region 234 at least partially overlap. Figures 4 to 7 The direction perpendicular to the planar region 234 is the thickness direction X, and the projections of the third cathode tab 231c, the second cathode tab 231b and the first cathode tab 231a along the thickness direction X at least partially overlap. It can be understood that, among the projections of the third cathode tab 231c, the second cathode tab 231b and the first cathode tab 231a, any two of them have an intersection part, or all of them have an intersection part, or the third cathode tab 231c, the second cathode tab 231b and the first cathode tab 231a have the same size and their edges are aligned with each other, thereby facilitating the welding of the third cathode tab 231c, the second cathode tab 231b and the first cathode tab 231a together.

[0109] Each of the multiple turns of the outer cathode tab 2312 continuously wound forms includes both the second cathode tab 231b and the third cathode tab 231c, i.e., each turn has two tabs. Compared with only one tab on each turn, the two tabs can withstand large current under high charge and discharge rate, thereby improving the reliability of the electrode assembly 23.

[0110] In some embodiments, each of the multiple turns of the outer cathode tab 2312 continuously wound forms includes two opposite planar regions 234, the second cathode tab 231b is located in one of the planar regions 234, and the third cathode tab 231c is located in the other planar region 234, i.e., each layer of the outer cathode tab 2312 has one tab.

[0111] By additionally providing the third cathode tab 231c, the demand for allowing large current to pass under high charge and discharge rate can be met. Meanwhile, by arranging the third cathode tab 231c, the second cathode tab 231b and the first cathode tab 231a in an overlapping manner, the third cathode tab 231c, the second cathode tab 231b and the first cathode tab 231a are facilitated to be welded together, so as to connect the inner cathode tab 2311 and the outer cathode tab 2312 as a whole.

[0112] ​

[0113] As shown in Figures 4 to 7 According to some embodiments of the present application, each of the multiple turns of the continuously wound anode tab 232 is provided with a first anode lug 232a extending along the height direction Z of the electrode assembly 23, and the projection of the first anode lug 232a along the direction perpendicular to the planar region 234 is completely staggered with the projection of the first cathode lug 231a along the direction perpendicular to the planar region 234.

[0114] For the anode tab 232, the site where the anode active material is coated on the foil forms an active material region of the anode tab 232, and the site where the active material is not coated on the foil forms the first anode lug 232a extending along the height direction Z of the electrode assembly 23. Each of the multiple turns of the continuously wound anode tab 232 is provided with the first anode lug 232a, so that there are enough lugs on the entire anode tab 232 to pass a larger current.

[0115] The projection of the first anode lug 232a along the direction perpendicular to the planar region 234 is completely staggered with the projection of the first cathode lug 231a along the direction perpendicular to the planar region 234, and it can be understood that the projection of the first anode lug 232a along the thickness direction X does not have an overlapping part with the projection of the first cathode lug 231a along the thickness direction X.

[0116] Along the height direction Z of the electrode assembly 23, the first anode lug 232a and the first cathode lug 231a can be located at opposite ends of the electrode assembly 23, and at this time, the projection of the first anode lug 232a and the projection of the first cathode lug 231a are in a completely staggered state. The first anode lug 232a and the first cathode lug 231a can be located on the same side of the electrode assembly, and at this time, the projection of the first anode lug 232a and the projection of the first cathode lug 231a are arranged in a staggered manner. The first anode lug 232a and the first cathode lug 231a in a staggered state are difficult to contact each other, reducing the risk of short circuit of the first anode tab 232a and the first cathode tab 231a due to contact with each other.

[0117] By providing the first anode lug 232a on each turn, there are enough lugs on the entire anode tab 232a to withstand a larger current. Moreover, the first anode lug 232a is staggered with the first cathode lug 231a, reducing the risk of short circuit of the first anode tab 232a and the first cathode tab 231a due to contact with each other.

[0118] As shown in Figures 4 to 7 According to some embodiments of the present application, each of the multiple turns of the continuously wound anode tab 232 is further provided with a second anode lug 232b extending along the height direction Z of the electrode assembly 23, and the projection of the second anode lug 232b along the direction perpendicular to the planar region 234 at least partially overlaps with the projection of the first anode lug 232a along the direction perpendicular to the planar region 234.

[0119] Each turn of the multi-turn structure formed by the continuous winding of the anode electrode 232 includes both a first anode tab 232a and a second anode tab 232b, that is, each turn has two tabs. Compared with only one tab on each turn, two tabs can withstand large currents under high charge and discharge rates, thus improving the reliability of the electrode assembly 23.

[0120] In some embodiments, each turn of the multi-turn structure formed by the continuous winding of the anode electrode 232 includes two opposing planar regions 234, with the first anode tab 232a located in one of the planar regions 234 and the second anode tab 232b located in the other planar region 234, that is, each layer of the anode electrode 232 has a tab.

[0121] The projections of the second anode tab 232b and the first anode tab 232a along a direction perpendicular to the plane region 234 at least partially overlap. It is understood that the projections of the second anode tab 232b and the first anode tab 232a intersect, or the second anode tab 232b and the first anode tab 232a are the same size and their edges are aligned, thereby facilitating the welding of the second anode tab 232b and the first anode tab 232a together.

[0122] By adding a second anode tab 232b, the requirement for a large current to pass through under high charge / discharge rates can be met. At the same time, the overlapping arrangement of the second anode tab 232b and the first anode tab 232a facilitates the welding of the second anode tab 232b and the first anode tab 232a together.

[0123] like Figure 8 As shown, Figure 8 This is the third schematic diagram of the electrode assembly structure according to some embodiments of this application. According to some embodiments of this application, the first cathode tab 231a is a full tab, and each turn of the multi-turn structure formed by the continuous winding of the outer cathode electrode 2312 is provided with a fourth cathode tab 231d extending along a first direction F1. Each turn of the multi-turn structure formed by the continuous winding of the anode electrode 232 is provided with a third anode tab 232c extending along a second direction F2 opposite to the first direction F1. The first direction F1 and the second direction F2 are parallel to the height direction Z of the electrode assembly 23. The fourth cathode tab 231d and the third anode tab 232c are full tabs.

[0124] A full tab refers to a region of uncoated foil at the edge of the current collector when the active material is coated on the current collector. This uncoated foil region is not die-cut, making it a continuous structure. In other words, the overall length of the uncoated foil region is equal to the overall length of the current collector. This uncoated foil region serves as a full tab. A full tab can increase the connection area of ​​the tab, thereby reducing the internal resistance of the battery cell 20 and reducing energy loss, thus improving the efficiency and lifespan of the battery cell 20.

[0125] The first direction F1 and the second direction F2 are both parallel to the axis of winding of the anode tab 232. The first cathode tab 231a and the fourth cathode tab 231d are located at one end of the electrode assembly 23, and the third anode tab 232c is located at the other end of the electrode assembly 23.

[0126] By setting the first cathode tab 231a, the fourth cathode tab 231d and the third anode tab 232c as full tabs, the overcurrent area can be increased, and the overcurrent capacity and charge-discharge performance of the battery can be improved.

[0127] The embodiments of the second aspect of the application provide a battery device 100, which includes the battery cell 20 described in any of the above embodiments.

[0128] The battery device 100 in the embodiments can have all the beneficial effects of the battery cell described above, which will not be repeated here.

[0129] The embodiments of the third aspect of the application provide a power consumption device, which includes the battery device 100 described in any of the above embodiments, and the battery device 100 is used to provide electric energy.

[0130] The power consumption device in the embodiments can have all the beneficial effects of the battery device described above, which will not be repeated here.

[0131] The following will be described in detail Figures 4 to 8 The embodiments of the application will be described in further detail.

[0132] The battery cell 20 includes an electrode assembly 23, the electrode assembly 23 includes cathode tabs 231 and anode tabs 232 which are alternately stacked, and a separator 233 between the cathode tabs 231 and the anode tabs 232. The anode tabs 232 and the separator 233 are continuous winding structures, and the cathode tabs 231 include inner cathode tabs 2311 located in the inner circle of the electrode assembly and outer cathode tabs 2312 located in the outer circle of the electrode assembly, the inner cathode tabs 2311 are stacked structures, and the outer cathode tabs 2312 are continuous winding structures. The electrode assembly 23 includes a planar region 234 and a bending region 235, and the projection of the active material region of the inner cathode tab 2311 along the thickness direction X completely falls into the planar region 234.

[0133] The inner cathode tab 2311 is a 4-layer stack, and each layer of the inner cathode tab 2311 is provided with a first cathode lug 231a. Each winding of the outer cathode tab 2312 is provided with a second cathode lug 231b and a third cathode lug 231c, the second cathode lug 231b and the third cathode lug 231c are oppositely arranged, the first cathode lug 231a, the second cathode lug 231b and the third cathode lug 231c have the same size and edge alignment, so as to be welded together to form a cathode lug.

[0134] Each winding of the anode tab 232 is provided with a first anode lug 232a and a second anode lug 232b, the first anode lug 232a and the second anode lug 232b are oppositely arranged, the first anode lug 232a and the second anode lug 232b have the same size and edge alignment, so as to be welded together to form an anode lug. The projection of the cathode lug and the anode lug in the thickness direction X is completely staggered.

[0135] The battery cell 20 of the embodiment is provided with the inner cathode tab 2311 in the inner circle of the electrode assembly in a stack structure, the anode tab 232, the separator 233 and the outer cathode tab 2312 in the outer circle of the electrode assembly in a continuous winding structure, and the active material area of the inner cathode tab 2311 avoids the bending area 235, thereby reducing the fracture of the inner cathode tab 2311 in the inner circle, improving the overall production efficiency and the energy density.

[0136] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the specification of the present application. Especially, as long as there is no structural conflict, each technical feature 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 by, The electrode assembly comprises: an electrode assembly comprising cathode and anode electrode sheets alternately stacked, and a separator between the cathode and anode electrode sheets; the anode electrode sheet and the separator are in a continuous winding structure; the cathode electrode sheet comprises an inner cathode electrode sheet, and an outer cathode electrode sheet continuously wound along the outer periphery of the inner cathode electrode sheet; wherein the electrode assembly comprises a planar region and a bending region, the bending region is located at opposite ends of the planar region along the length direction of the electrode assembly, and the projection of the active material region of the inner cathode electrode sheet along the direction perpendicular to the planar region completely falls within the range of the active material region of the adjacent anode electrode sheet.

2. The battery cell of claim 1, wherein, In the planar region, the projection of the active material region of the inner cathode electrode sheet along the direction perpendicular to the planar region completely falls within the range of the active material region of the adjacent anode electrode sheet.

3. The battery cell of claim 1, wherein, The inner cathode electrode sheet is in a continuous winding structure, and along the length direction of the inner cathode electrode sheet, the active material region and the blank region of the inner cathode electrode sheet are arranged alternately, the active material region is located in the planar region, and the blank region is located in the bending region. The blank region is a part of the inner cathode electrode sheet that is not coated with active material.

4. The battery cell of claim 1, wherein, The inner cathode electrode sheet is in a laminated structure.

5. The battery cell of claim 4, wherein, The proportion of the number of layers of the inner cathode electrode sheet to the total number of layers of the cathode electrode sheet is greater than or equal to 10% and less than or equal to 20%. The total number of layers of the cathode electrode sheet is the sum of the number of layers of the inner cathode electrode sheet and the number of layers of the outer cathode electrode sheet, and the number of layers of the outer cathode electrode sheet is the number of layers of the outer cathode electrode sheet along the direction perpendicular to the planar region.

6. The battery cell of claim 5, wherein, The number of layers of the inner cathode electrode sheet is greater than or equal to 2 and less than or equal to 10.

7. The battery cell of any one of claims 4-6, wherein, Each part of the inner cathode electrode sheet located in the planar region has a first cathode tab extending along the height direction of the electrode assembly.

8. The battery cell of claim 7, wherein, Each turn of the outer cathode electrode sheet in the multi-turn structure formed by continuous winding is provided with a second cathode tab extending along the height direction of the electrode assembly, and the projection of the second cathode tab along the direction perpendicular to the planar region at least partially overlaps the projection of the first cathode tab.

9. The battery cell of claim 8, wherein, Each turn of the outer cathode electrode sheet in the multi-turn structure formed by continuous winding is also provided with a third cathode tab extending along the height direction of the electrode assembly, and the projection of the third cathode tab along the direction perpendicular to the planar region at least partially overlaps the projection of the second cathode tab and the first cathode tab.

10. The battery cell of claim 7, wherein, Each turn of the anode electrode sheet in the multi-turn structure formed by continuous winding is provided with a first anode tab extending along the height direction of the electrode assembly, and the projection of the first anode tab along the direction perpendicular to the planar region completely overlaps the projection of the first cathode tab.

11. The battery cell of claim 10, wherein, Each turn of the anode electrode sheet in the multi-turn structure formed by continuous winding is also provided with a second anode tab extending along the height direction of the electrode assembly, and the projection of the second anode tab along the direction perpendicular to the planar region at least partially overlaps the projection of the first anode tab.

12. The battery cell of claim 7, wherein, The first cathode tab is a full tab. Each of the multiple turns of the outer cathode tab continuously wound forms a turn provided with a fourth cathode lug extending in a first direction, and each of the multiple turns of the anode tab continuously wound forms a turn provided with a third anode lug extending in a second direction opposite to the first direction; the first direction and the second direction are parallel to the height direction of the electrode assembly; The fourth cathode lug and the third anode lug are full lugs.

13. A battery device characterized by comprising: A battery cell comprising any of the battery cells of claims 1-12.

14. An electrical device, characterized by An electrical device comprising the battery device of claim 13, the battery device being configured to provide electrical energy.

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