Battery cell, battery device, and electric device

Abstract

The application relates to the technical field of battery production, in particular to a battery monomer, a battery device and a power utilization equipment. The battery monomer comprises an electrode assembly, the electrode assembly comprises a diaphragm and a pole piece, the pole piece is arranged on one side of the diaphragm, and the pole piece is provided with a thinning area at the edge position in a first direction; the diaphragm comprises a base film and a coating layer, the coating layer is arranged on the surface of at least one side of the base film in a second direction, the coating layer comprises a first coating layer area and a second coating layer area, the two sides of the first coating layer area in the first direction are respectively provided with the second coating layer area, the second coating layer area is arranged in correspondence with the thinning area, the second coating layer area is arranged in the thinning area, and the surface of the coating layer facing the pole piece is arranged in close contact with the pole piece; the first direction intersects the second direction, and the first direction is the height direction of the battery monomer. The battery monomer compensates the thickness of the thinning area through the second coating layer area, increases the strength of the edge of the diaphragm in the first direction, and reduces the probability of the diaphragm being damaged by being turned over in the process of winding or laminating.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery production, and in particular to a battery monomer, a battery device and an electric equipment. BACKGROUND

[0002] The part provided in this part is only background information related to the present disclosure, which is not necessarily prior art.

[0003] With the increasing maturity of new energy technology, new energy vehicles and other electric equipment have gradually entered the public eye. The main core technology of new energy vehicles is the battery device, and the safety and stability of the battery device directly determine the performance of the whole vehicle.

[0004] The battery device includes a battery monomer, the battery monomer includes an electrode assembly, and the electrode assembly includes a separator, a positive electrode sheet and a negative electrode sheet. The separator is placed between the positive electrode sheet and the negative electrode sheet, and plays a role of isolating electrons and conducting ions, which is the key to the safe operation of the lithium ion battery.

[0005] The separator includes a base film and a coating layer, and the coating layer is arranged on the surface of at least one side of the base film in the thickness direction. The separator with such a structure is prone to folding and breaking during winding or lamination. SUMMARY

[0006] In view of the above problems, the present application provides a battery monomer, a battery device and an electric equipment, which solves the problem that the separator in the prior art is prone to folding and breaking during winding or lamination.

[0007] A first aspect of an embodiment of the present application provides a battery monomer, which includes:

[0008] An electrode assembly, the electrode assembly includes a separator and a sheet, the sheet is arranged on one side of the separator, and the sheet is provided with a thinning area at the edge position in a first direction;

[0009] The separator includes a base film and a coating layer, and the coating layer is arranged on the surface of at least one side of the base film in a second direction. The coating layer includes a first coating area and a second coating area, wherein the two sides of the first coating area in the first direction are respectively provided with the second coating area, the second coating area is arranged corresponding to the thinning area, and the second coating area is arranged in the thinning area. The surface of the coating layer facing the sheet is arranged in close contact with the sheet. The first direction intersects the second direction, and the first direction is the height direction of the battery monomer.

[0010] The embodiment of the present application can realize compensation of the thickness of the thinning area through the second coating area, increase the strength of the edge of the diaphragm along the first direction, and reduce the probability of the diaphragm being damaged by being folded during the winding or lamination.

[0011] In some embodiments of the present application, the coating layer further comprises a third coating area, the third coating area is arranged on the side of the second coating area away from the first coating area, and the minimum dimension of the third coating area along the second direction is greater than or equal to the maximum dimension of the second coating area along the second direction.

[0012] The embodiment of the present application can realize compensation of the thickness of the thinning area through the second coating area, increase the strength of the edge of the diaphragm along the first direction, and reduce the probability of the diaphragm being damaged by being folded during the winding or lamination.

[0013] In some embodiments of the present application, the dimensions of at least part of the third coating area along the second direction are consistent.

[0014] The embodiment of the present application can realize compensation of the thickness of the thinning area through the second coating area, increase the strength of the edge of the diaphragm along the first direction, and reduce the probability of the diaphragm being damaged by being folded during the winding or lamination.

[0015] In some embodiments of the present application, the number of the pole pieces is two, and the two pole pieces include a positive pole piece, the positive pole piece includes a first foil and a first film area which are stacked and connected, the first film area is arranged to face the base film, the thinning area includes a first thinning area arranged on the first film area; the third coating area includes a first sub-coating area, the first sub-coating area is arranged on the side of the base film facing the positive pole piece; along the second direction, the dimension of the first sub-coating area is greater than or equal to the maximum dimension of the first thinning area, and is less than or equal to the sum of the dimension of the first film area and the dimension of the first foil.

[0016] The embodiment of the present application can determine the size of the first sub-coating layer region in the second direction, control the size of the first sub-coating layer region in the second direction, facilitate the assembly of the diaphragm, and reduce the probability of interference of the first sub-coating layer region in the process of winding or lamination.

[0017] In some embodiments of the present application, the size of the first sub-coating layer region in the second direction is T, the maximum size of the first film region in the second direction is T1, the size of the first foil in the second direction is T2, and the maximum size of the first thinning region in the second direction is T3, and T3≤T≤T1+0.5*T2.

[0018] The embodiment of the present application can determine the specific range value of the first sub-coating layer region in the second direction by setting the size of the first sub-coating layer region in the second direction as T, the maximum size of the first film region in the second direction as T1, the size of the first foil in the second direction as T2, and the maximum size of the first thinning region in the second direction as T3, wherein T3≤T≤T1+0.5*T2, so that the size of the first sub-coating layer region in the second direction is within an appropriate range, and the situation that the size of the first sub-coating layer region in the second direction is too small to increase the strength obviously or the situation that the size of the first sub-coating layer region in the second direction is too large to waste the slurry does not occur.

[0019] In some embodiments of the present application, the two electrode sheets further include a negative electrode sheet, the negative electrode sheet and the positive electrode sheet are respectively arranged on opposite sides of the diaphragm, the negative electrode sheet includes a second foil and a second film region which are stacked and connected, the thinning region includes a second thinning region arranged on the second film region and facing the base film, and the third coating layer region includes a second sub-coating layer region, the second sub-coating layer region is arranged on the side of the base film facing the negative electrode sheet, the size of the second sub-coating layer region in the second direction is greater than or equal to the maximum size of the second thinning region, and is less than or equal to the sum of the size of the second film region and the size of the second foil.

[0020] Embodiments of the present application can determine the size of the second sub-coating area in the second direction, control the size of the second sub-coating area in the second direction, facilitate the assembly of the separator, and reduce the probability of interference of the second sub-coating area in the process of winding or stacking, by setting the negative electrode sheet, wherein the negative electrode sheet includes a second foil and a second film area connected in layers, the thinning area includes a second thinning area arranged on the second film area and facing the base film, the third coating area includes a second sub-coating area arranged on the side of the base film facing the negative electrode sheet, the size of the second sub-coating area in the second direction is greater than or equal to the maximum size of the second thinning area, and less than or equal to the sum of the size of the second film area and the size of the second foil.

[0021] In some embodiments of the present application, the size of the second sub-coating area in the second direction is T4, the maximum size of the second film area in the second direction is T6, the size of the second foil in the second direction is T7, and the maximum size of the second thinning area in the second direction is T5, and T5≤T4≤T6+0.5*T7.

[0022] Embodiments of the present application can determine the specific range value of the second sub-coating area in the second direction by setting the size of the second sub-coating area in the second direction as T4, the maximum size of the second film area in the second direction as T6, the size of the second foil in the second direction as T7, and the maximum size of the second thinning area in the second direction as T5, wherein T5≤T4≤T6+0.5*T7, so that the size of the second sub-coating area in the second direction is within an appropriate range, without the situation that the size of the second sub-coating area in the second direction is too small to increase the strength obviously, or the situation that the size of the second sub-coating area in the second direction is too large to waste the slurry.

[0023] In some embodiments of the present application, the first coating area includes a first part, the second coating area includes a third part, and the first part and the third part are arranged between the base film and the negative electrode sheet; a polycarbosilane layer is arranged on the surface of at least one of the first part, the third part, and the second sub-coating area.

[0024] Embodiments of the present application can make the separator and the separator, and the separator and the electrode sheet closely bonded together in the subsequent shaping process by setting the first part and the third part, wherein the first part and the third part are arranged between the base film and the negative electrode sheet, and a polycarbosilane layer is arranged on the surface of at least one of the first part, the third part, and the second sub-coating area.

[0025] In some embodiments of the present application, the polycarbosilane layer is distributed in a dot shape on the surface of at least one of the first part, the third part, and the second sub-coating area.

[0026] The embodiments of the present application can provide adhesion by the dot-distributed polycarbosilane layer, and the dot-distributed polycarbosilane layer has a thinner thickness and a lower cost compared with the polycarbosilane layer in a layered structure.

[0027] In some embodiments of the present application, the second coating region further comprises a fourth portion, the fourth portion and the third portion are respectively arranged on opposite sides of the base film; a first transition region is arranged at a connection position of the third portion and the second sub-coating region; and / or a second transition region is arranged at a connection position of the fourth portion and the first sub-coating region.

[0028] The embodiments of the present application can facilitate the assembly of the negative electrode sheet through the first transition region and the assembly of the positive electrode sheet through the second transition region, so that the positive electrode sheet, the separator and the negative electrode sheet are assembled together according to the predetermined route, the deviation can be better controlled, and the probability of deviation of the positive electrode sheet or the negative electrode sheet is reduced.

[0029] In some embodiments of the present application, the electrode sheet is provided with a third coating region on each side along the first direction, and an edge of the third coating region along the first direction is flush with a corresponding edge of the base film.

[0030] The embodiments of the present application can cover the area of the edge position of the base film by the third coating region, and increase the strength of the separator at the edge position.

[0031] A second aspect of the embodiments of the present application provides a battery device, which comprises:

[0032] The battery cell as mentioned in the above embodiments; and a box, wherein the battery cell is arranged in the box.

[0033] A third aspect of the embodiments of the present application provides a power consumption device, which comprises the battery cell as mentioned in the above embodiments.

[0034] The above description is only a summary of the technical solutions of the present application, in order to more clearly understand the technical means of the present application, the specific embodiments of the present application can be implemented according to the content of the description, 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

[0035] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments with reference made to the accompanying drawings. The drawings are for purposes of illustration only and are not intended to be limiting in

[0036] Figure 1 A structural schematic diagram of a power-using device according to some embodiments of the present application;

[0037] Figure 2 A structural schematic diagram of a battery device according to some embodiments of the present application;

[0038] Figure 3 A structural schematic diagram of an electrode assembly of a battery cell shown in Figure 1

[0039] A structural schematic diagram of an electrode assembly of a battery cell shown in Figure 4 Figure 3 A structural schematic diagram of an electrode assembly of a battery cell shown in

[0040] Figure 5 Figure 3 A structural schematic diagram of an electrode assembly of a battery cell shown in

[0041] Figure 6 A structural schematic diagram of an electrode assembly of a battery cell shown in Figure 5

[0042] Reference signs are as follows:

[0043] 1000, vehicle; 100, battery device; 200, controller; 300, motor;

[0044] 10, battery cell; 1, electrode assembly; 11, separator; 111, base film; 112, coating layer; 1121, first coating region; 11211, first portion; 11212, second portion; 1122, second coating region; 11221, third portion; 11222, fourth portion; 1123, third coating region; 11231, first sub-coating region; 11232, second sub-coating region; 12, electrode tab; 121, positive electrode tab; 1211, first film region; 1212, first foil; 1213, third film region; 122, negative electrode tab; 1221, second film region; 1222, second foil; 1223, fourth film region; 13, thinning region; 131, first thinning region; 132, second thinning region; 14, polycarbosilane layer; 15, insulating layer; 16, first turning region; 17, second turning region;

[0045] 20, case; 21, first case; 22, second case; 23, accommodation space;​​​

[0046] T, the dimension of the first sub-coating region along the second direction;

[0047] T1, the maximum dimension of the first film region along the second direction;

[0048] T2, the dimension of the first foil along the second direction;

[0049] T3, the maximum dimension of the first thinned region along the second direction;

[0050] T4, the dimension of the second sub-coating region along the second direction;

[0051] T5, the maximum dimension of the second thinned region along the second direction;

[0052] T6, the maximum dimension of the second film region along the second direction;

[0053] T7, the dimension of the second foil along the second direction;

[0054] X-X, the first direction;

[0055] Y-Y, the second direction. DETAILED DESCRIPTION

[0056] The embodiments of the technical scheme of the present application will be described in detail below with reference to the drawings. The following embodiments are only used to more clearly illustrate the technical scheme of the present application, and therefore only serve as examples, and cannot limit the protection scope of the present application.

[0057] 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 terms used herein are only for the purpose of describing specific embodiments of the present application, and are not intended to limit the present application; the terms "include" and "have" and any variations thereof in the specification and claims of the present application and the above description of drawings are intended to cover non-exclusive inclusion.

[0058] 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.

[0059] Reference to“an embodiment” herein 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 appearances of the phrase“in an embodiment” in various places in the specification are not necessarily referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. As will be apparent to those of ordinary skill in the art, embodiments described herein can be combined with other embodiments in accordance with the application.

[0060] In the description of the embodiments of the application, the term“and / or” only means an association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can mean that A exists alone, A and B exist together, and B exists alone. In addition, the character“ / ” herein generally means that the front and rear associated objects have an“or” relationship.

[0061] In the description of the embodiments of the application, the term“a plurality of” means two or more (including two), and similarly, “a plurality of groups” means two or more groups (including two groups), and “a plurality of pieces” means two or more pieces (including two pieces).

[0062] In the description of the embodiments of the application, 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” and“circumferential” indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the 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 application.

[0063] In the description of the embodiments of the application, unless otherwise explicitly specified and limited, the technical terms“mounting”,“connection”,“connection” and“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; can be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the application can be understood according to the specific circumstances.

[0064] At present, from the development of market situation, the application of battery apparatus is more and more extensive. The battery apparatus is not only applied to the energy storage power supply system of hydropower, thermal power, wind power and solar power station, but also widely applied to electric vehicles such as electric bicycles, electric motorcycles, electric vehicles, electric vehicles, military equipment and aerospace and other fields. With the continuous expansion of the application field of battery apparatus, the demand of its market is also increasing.

[0065] The battery apparatus related to the embodiments of the present application can be used in, but not limited to, electric equipment such as vehicles, ships or aircraft. The battery apparatus can be used to form the battery apparatus of the electric equipment.

[0066] The electric equipment using the battery apparatus as power supply in the embodiments of the present application can be, but not limited to, mobile phones, tablets, notebook computers, electric toys, electric tools, electric cars, electric cars, ships, spacecraft and the like. Among them, the electric toys can include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys and electric plane toys, and the like. Spacecraft can include aircraft, rockets, space shuttles and spacecraft, and the like.

[0067] It should be understood that the technical solutions described in the embodiments of the present application are not only limited to the above described battery apparatus and electric equipment, but also can be applied to all batteries including the box and the electric equipment using the battery.

[0068] The battery apparatus mentioned in the embodiments of the present application can include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly can include a plurality of battery cells connected in series, parallel or mixed connection through the busbar component.

[0069] In some embodiments, the battery cell assembly is usually formed by arranging a plurality of battery cells.

[0070] As an example, the battery cell assembly can be a battery module formed by arranging and fixing a plurality of battery cells into an independent module. As an example, the battery module can be formed by binding a plurality of battery cells with a cable tie.

[0071] In some embodiments, the battery apparatus can be a battery pack, which includes a box and one or more battery cell assemblies, and the battery cell assemblies are contained in the box.

[0072] As an example, the battery cell assembly can be a battery module, and the battery cell assembly can be accommodated in the case by fixing the battery module in the case.

[0073] As an example, the battery cell assembly can also be accommodated in the case by fixing a plurality of battery cells directly in the case.

[0074] As an example, the case can include a first case and a second case. The first case and the second case are fastened so that an enclosed space is formed inside the case to accommodate the battery cell assembly. Here, enclosed means covered or closed, which can be sealed or unsealed. The first case can be a top cover or a bottom plate.

[0075] As an example, the case can include a top cover, a frame, and a bottom plate. The top cover and the bottom plate are connected to the frame, so that an enclosed space is formed inside the case to accommodate the battery cell assembly.

[0076] In some embodiments, the case can be part of the chassis structure of a vehicle. For example, part of the case can be at least part of the floor of the vehicle, or part of the case can be at least part of the cross beams and longitudinal beams of the vehicle.

[0077] The battery cell includes an electrode assembly and an electrolyte. The electrode assembly is composed of a positive electrode sheet, a negative electrode sheet, and a separator. The battery cell mainly works by moving metal ions between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer, and the positive electrode active material layer is coated on the surface of the positive electrode current collector. The current collector without the positive electrode active material layer protrudes from the current collector with the positive electrode active material layer, and the current collector without the positive electrode active material layer is stacked as a positive electrode tab. Taking a lithium ion battery as an example, the material of the positive electrode current collector can be aluminum, and the positive electrode active material can be lithium cobaltate, lithium iron phosphate, ternary lithium, or lithium manganate, etc. The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer, and the negative electrode active material layer is coated on the surface of the negative electrode current collector. The current collector without the negative electrode active material layer protrudes from the current collector with the negative electrode active material layer, and the current collector without the negative electrode active material layer is stacked as a negative electrode tab. The material of the negative electrode current collector can be copper, and the negative electrode active material can be carbon or silicon, etc. The material of the separator can be PP (polypropylene) or PE (polyethylene), etc. In addition, the electrode assembly can be a wound structure or a stacked structure, and the embodiments of the present application are not limited thereto.

[0078] The technical solutions described in the embodiments of the present application are applicable to various electric devices using battery cells, such as mobile phones, portable devices, notebook computers, electric vehicles, electric toys, electric tools, vehicles, ships, and spacecraft, etc. For example, the spacecraft includes an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0079] The electrode assembly includes a separator, a positive electrode sheet and a negative electrode sheet, wherein the separator is arranged between the positive electrode sheet and the negative electrode sheet to insulate electrons and conduct ions, and is a key to safe operation of the lithium ion battery. The separator includes a base film and a coating layer, wherein the coating layer is arranged on the surface of at least one side of the base film in the thickness direction. The separator with such a structure is prone to folding and breaking during winding or stacking.

[0080] To solve this problem, the embodiments of the present application provide a battery monomer, which includes an electrode assembly, the electrode assembly includes a separator and a sheet, the sheet is arranged on one side of the separator, and the sheet is provided with a thinned area at the edge position in a first direction; the separator includes a base film and a coating layer, the coating layer is arranged on the surface of at least one side of the base film in a second direction, the coating layer includes a first coating area and a second coating area, wherein the two sides of the first coating area in the first direction are respectively provided with the second coating area, the second coating area is arranged corresponding to the thinned area, and the second coating area is arranged in the thinned area, and the surface of the coating layer facing the sheet is arranged in close contact with the sheet; the first direction intersects the second direction, and the first direction is the height direction of the battery monomer. In the embodiments of the present application, the coating layer is arranged on the surface of at least one side of the base film in the second direction, wherein the coating layer includes a first coating area and a second coating area, wherein the two sides of the first coating area in the first direction are respectively provided with the second coating area, the second coating area is arranged corresponding to the thinned area, and the second coating area is arranged in the thinned area, and the surface of the coating layer facing the sheet is arranged in close contact with the sheet. Therefore, the second coating area can compensate for the thickness of the thinned area, increase the strength of the edge of the separator in the first direction, and reduce the probability of folding and breaking of the separator during winding or stacking.

[0081] The battery monomer in the embodiments of the present application can be used on an electric device such as a vehicle, and can be installed on an electric device that needs to be installed in advance.

[0082] The structure in the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0083] In combination Figure 1 As shown in the figure, the vehicle 1000 can be a fuel automobile, a gas automobile or a new energy automobile, and the new energy automobile can be a pure electric automobile, a hybrid automobile or a range extended automobile. 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 also 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 working power demand of the vehicle 1000 during starting, navigation and driving.

[0084] In some embodiments of the present application, the battery device 100 can not only serve as the operating power source of the vehicle 1000, but also serve as the driving power source of the vehicle 1000, replacing or partially replacing the fuel or natural gas to provide driving power for the vehicle 1000.

[0085] As shown in Figure 2 , the embodiments of the present application also provide a battery device 100, comprising a battery box 20 and a battery cell 10, wherein the battery box 20 is provided with a containing space 23, and the battery cell 10 is installed in the containing space 23.

[0086] In some embodiments, as shown in Figure 2 , the battery box 20 can comprise a first box 21 and a second box 22, the first box 21 and the second box 22 are overlapped with each other, and the first box 21 and the second box 22 jointly define the containing space 23 for containing the battery cell 10. Wherein, the first box 21 and the second box 22 can both be a hollow structure with one end open, and the second box 22 is overlapped with the open side of the first box 21 to jointly define the containing space with the first box 21; or the second box 22 can be a plate structure, and the first box 21 can be a hollow structure with one side open, and the open side of the second box 22 is overlapped with the open side of the first box 21. Of course, the battery box 20 formed by the first box 21 and the second box 22 can be in various shapes, such as a cylinder, a cuboid, etc.

[0087] The battery cell 10 can be a secondary battery or a primary battery, and can also be a lithium-sulfur battery, a sodium-ion battery or a magnesium-ion battery, but is not limited thereto. The battery cell 10 can be in the shape of a cylinder, a flat body, a cuboid or other shapes, etc.

[0088] As shown in Figures 3 to 6 , the battery cell 10 comprises an electrode assembly 1, the electrode assembly 1 comprises a separator 11 and a pole piece 12, the pole piece 12 is arranged on one side of the separator 11, and the pole piece 12 is provided with a thinning area 13 at the edge position in the first direction; the separator 11 comprises a base film 111 and a coating layer 112, the coating layer 112 is arranged on the surface of at least one side of the base film 111 in the second direction, the coating layer 112 comprises a first coating area 1121 and a second coating area 1122, wherein the first coating area 1121 is respectively provided with the second coating area 1122 on both sides in the first direction, the second coating area 1122 is arranged corresponding to the thinning area 13, and the second coating area 1122 is arranged in the thinning area 13, and the surface of the coating layer 112 facing the pole piece 12 is arranged in close contact with the pole piece 12; the first direction intersects with the second direction, and the first direction is the height direction of the battery cell 10. Wherein, the first direction is the X-X direction in Figure 3 , and the second direction is the Y-Y direction in Figure 3 .

[0089] The electrode assembly 1 here is a core structural unit for the battery monomer 10 to realize an electrochemical reaction, and the electrode assembly 1 is usually formed through a winding process or a stacking process.

[0090] The thinning area 13 here is provided due to the flow casting of the pole piece 12 at the edge, and therefore, the thinning area 13 is usually provided at the edge of the pole piece 12 along the first direction, and the thinner the pole piece 12 is at the position closer to the edge, and therefore, the thinning area 13 can be a triangular space area. The edge position here refers to the area of the pole piece 12 close to the end along the first direction.

[0091] The coating layer 112 here includes a first coating area 1121 and a second coating area 1122, which are distinguished based on the setting position, wherein the first coating area 1121 is located at the middle position of the base film 111 along the first direction, the second coating area 1122 is located on both sides of the first coating area 1121 along the first direction, and is provided corresponding to the thinning area 13, and is used to compensate for the thinning area 13.

[0092] The first coating area 1121 and the second coating area 1122 can be coated by using strength-enhancing slurry, wherein the strength-enhancing slurry includes a strength component, a binder, and a dispersant. Specifically, the strength component can be boehmite, aluminum oxide, calcium hydroxide, manganese carbonate, and other inorganic salts that have a certain strength but do not affect the performance of the battery. The solvent can be deionized water, N-methyl pyrrolidone, etc. The binder can be a combination of polyvinylidene fluoride (PVDF), styrene-butadiene rubber (SBR), and sodium carboxymethyl cellulose (CMC). The dispersant generally uses polyethylene glycol (PEG). The ratio of the strength component, the binder, and the dispersant can be 80-90wt%:9-15wt%:1-5wt%, specifically, the ratio of the strength component, the binder, and the dispersant can be 85wt%, 10wt%, and 5wt% or 88wt%, 11wt%, and 1wt%.

[0093] The embodiment of the present application provides a coating layer 112 on the surface of at least one side of the base film along the second direction, wherein the coating layer 112 includes a first coating area 1121 and a second coating area 1122, wherein the first coating area 1121 is provided with the second coating area 1122 on both sides along the first direction, the second coating area 1122 is provided corresponding to the thinning area 13, and the second coating area 1122 is provided in the thinning area 13, and the surface of the coating layer 112 facing the pole piece 12 is provided in close contact with the pole piece 12, so that the second coating area 1122 can compensate for the thickness of the thinning area 13, increase the strength of the edge of the diaphragm 11 along the first direction, and reduce the probability of damage caused by folding of the diaphragm 11 in the winding or stacking process.

[0094] In some embodiments of the present application, as Figure 3 and Figure 4As shown, the coating layer 112 further comprises a third coating area 1123, the third coating area 1123 is arranged on the side of the second coating area 1122 away from the first coating area 1121, and the minimum size of the third coating area 1123 along the second direction is greater than or equal to the maximum size of the second coating area 1122 along the second direction.

[0095] It should be noted that the boundary between the third coating area 1123 and the second coating area 1122 can be the edge of the positive electrode sheet 121 along the first direction, that is, the third coating area 1123 is arranged protruding from the corresponding edge of the electrode sheet 12 along the first direction, which can further enhance the strength of the separator 11 at the edge position. Specifically, the number of third coating areas 1123 is two, wherein the third coating area 1123 located above the electrode sheet 12 protrudes from the upper edge of the electrode sheet 12, and the third coating area 1123 located below the electrode sheet 12 protrudes from the lower edge of the electrode sheet 12. Here, the electrode sheet 12 can be the positive electrode sheet 121 or the negative electrode sheet 122.

[0096] The embodiments of the present application can further increase the strength of the separator 11 at the edge position by arranging the third coating area 1123 on the side of the second coating area 1122 away from the first coating area 1121, and the minimum size of the third coating area 1123 along the second direction is greater than or equal to the maximum size of the second coating area 1122 along the second direction. The third coating area 1123 can be used to coat the separator 11 protruding from the electrode sheet 12, further increasing the strength of the separator 11 at the edge position and reducing the probability of damage caused by folding during winding or stacking.

[0097] In some embodiments of the present application, the size of at least part of the third coating area 1123 along the second direction is consistent. That is, the cross-sectional shape of at least part of the third coating area 1123 is a rectangular structure, and the size of the rectangular structure along the second direction is consistent, so that the third coating area 1123 can be conveniently formed.

[0098] The embodiment of the present application can facilitate the processing of the third coating area 1123 and reduce the probability of interference of the third coating area 1123 in the process of winding or laminating the separator 11, by setting the size of the third coating area 1123 along the second direction to be consistent. Optionally, the number of the pole piece 12 is two, the two pole pieces 12 include a positive pole piece 121, the positive pole piece 121 includes a first foil 1212 and a first film area 1211 which are connected in a stack, the first film area 1211 is arranged to face the base film 111, the thinning area 13 includes a first thinning area 131, and the first film area 1211 is provided with the first thinning area 131; the third coating area 1123 includes a first sub-coating area 11231, and the first sub-coating area 11231 is arranged on the side of the base film 111 facing the positive pole piece 121; along the second direction, the size of the first sub-coating area 11231 is greater than or equal to the maximum size of the first thinning area 131, and is less than or equal to the sum of the size of the first film area 1211 and the size of the first foil 1212.

[0099] Optionally, as shown in Figure 3 , the positive pole piece 121 further includes a third film area 1213, the third film area 1213 and the first film area 1211 are respectively arranged on the opposite sides of the first foil 1212 along the second direction, and the first thinning area 131 is formed on the first film area 1211.

[0100] The embodiment of the present application can determine the size of the first sub-coating area 11231 along the second direction, achieve the size control of the first sub-coating area 11231 along the second direction, facilitate the assembly of the separator 11, and reduce the probability of interference of the first sub-coating area 11231 in the process of winding or laminating, by setting the positive pole piece 121, and the positive pole piece 121 includes a first foil 1212 and a first film area 1211 which are connected in a stack, the first film area 1211 is arranged to face the base film 111, and the first film area 1211 is provided with a first thinning area 131; the third coating area 1123 includes a first sub-coating area 11231, and the first sub-coating area 11231 is arranged on the side of the base film 111 facing the positive pole piece 121; along the second direction, the size of the first sub-coating area 11231 is greater than or equal to the maximum size of the first thinning area 131, and is less than or equal to the sum of the size of the first film area 1211 and the size of the first foil 1212.

[0101] Optionally, as shown in Figure 4 , the size of the first sub-coating area 11231 along the second direction is T, the maximum size of the first film area 1211 along the second direction is T1, the size of the first foil 1212 along the second direction is T2, the maximum size of the first thinning area 131 along the second direction is T3, and T3≤T≤T1+0.5*T2.

[0102] The embodiment of the present application can determine the specific range of the first sub-coating area 11231 along the second direction, so that the size of the first sub-coating area 11231 along the second direction is within a proper range, without the case that the size of the first sub-coating area 11231 along the second direction is too small to cause no obvious increase in strength, or the case that the size of the first sub-coating area 11231 along the second direction is too large to cause waste of slurry.

[0103] Specifically, T can be selected as T1+0.1*T2, or T can be selected as T1+0.2*T2, or T can be selected as T1+0.3*T2, or T can be selected as T1+0.4*T2.

[0104] Alternatively, as shown in FIG. 1C, the two polar pieces 12 further include a negative polar piece 122, the negative polar piece 122 and the positive polar piece 121 are respectively arranged on opposite sides of the separator 11 along the second direction, the negative polar piece 122 includes a second foil 1222 and a second film area 1221 which are stacked and connected, the thinning area 13 further includes a second thinning area 132, the second film area 1221 is provided with the second thinning area 132 facing the base film 111; the third coating area 1123 includes a second sub-coating area 11232, the second sub-coating area 11232 is arranged on the side of the base film 111 facing the negative polar piece 122; along the second direction, the size of the second sub-coating area 11232 is greater than or equal to the maximum size of the second thinning area 132, and is less than or equal to the sum of the size of the second film area 1221 and the size of the second foil 1222. Figure 3 It should be noted that the sizes of the second sub-coating area 11232 and the first sub-coating area 11231 along the second direction can be different, and the size of the second sub-coating area 11232 along the second direction or the size of the first sub-coating area 11231 along the second direction can be determined as needed.

[0105]

[0106] ​The embodiment of the present application sets the negative plate 122, wherein the negative plate 122 comprises the second foil 1222 and the second film area 1221 connected in layers, the second film area 1221 is provided with the second thinning area 132 facing the base film 111; the third coating area 1123 comprises the second sub-coating area 11232, the second sub-coating area 11232 is arranged on the side of the base film 111 facing the negative plate 122; along the second direction, the size of the second sub-coating area 11232 is greater than or equal to the maximum size of the second thinning area 132, and less than or equal to the sum of the size of the second film area 1221 and the size of the second foil 1222, so that the size of the second sub-coating area 11232 along the second direction can be determined, the size control of the second sub-coating area 11232 in the second direction is realized, the assembly of the separator 11 is facilitated, and the probability of interference of the second sub-coating area 11232 in the process of winding or lamination can be reduced.

[0107] Optionally, the size of the second sub-coating area 11232 along the second direction is T4, the maximum size of the second film area 1221 along the second direction is T6, the size of the second foil 1222 along the second direction is T7, and the maximum size of the second thinning area 132 along the second direction is T5, T5≤T4≤T6+0.5*T7.

[0108] Specifically, T4 can be selected as T6+0.1*T7, or T4 can be selected as T6+0.2*T7, or T4 can be selected as T6+0.3*T7, or T4 can be selected as T6+0.4*T7.

[0109] The embodiment of the present application sets the size of the second sub-coating area 11232 along the second direction as T4, the maximum size of the second film area 1221 along the second direction as T6, the size of the second foil 1222 along the second direction as T7, and the maximum size of the second thinning area 132 along the second direction as T5, wherein T5≤T4≤T6+0.5*T7, so that the specific range value of the second sub-coating area 11232 along the second direction can be determined, so that the size of the second sub-coating area 11232 along the second direction is within a suitable range, without the case that the size of the second sub-coating area 11232 along the second direction is too small to cause the strength to increase obviously, or the case that the size of the second sub-coating area 11232 along the second direction is too large to cause the slurry to be wasted.

[0110] Optionally, the size of the first sub-coating area 11231 along the second direction is generally between 30 microns and 80 microns, such as 30 microns, 40 microns, 50 microns, 60 microns, 70 microns or 80 microns, etc. The size of the second sub-coating area 11232 along the second direction is generally between 20 microns and 70 microns, such as 20 microns, 30 microns, 40 microns, 50 microns, 60 microns or 70 microns, etc.

[0111] Alternatively, the size of the first sub-coating region 11231 along the second direction can also be larger, for example, the first sub-coating region 11231 covers the upper surface of the positive electrode sheet 121 along the second direction, and similarly, the size of the second sub-coating region 11232 along the second direction can also be larger, for example, the first sub-coating region 11231 covers the upper surface of the negative electrode sheet 122 along the second direction.

[0112] Optionally, the first coating region 1121 includes a first part 11211, and the second coating region 1122 includes a third part 11221, the first part 11211 and the third part 11221 are both arranged between the base film 111 and the negative electrode sheet 122; and a polycarbosilane layer 14 is arranged on the surface of at least one of the first part 11211, the third part 11221 and the second sub-coating region 11232.

[0113] The polycarbosilane layer 14 here can be a layered structure or a point-like structure, wherein when the polycarbosilane layer 14 is a layered structure, it can be arranged between the first part 11211 and the negative electrode sheet 122, or between the third part 11221 and the negative electrode sheet 122, or between the second sub-coating region 11232 and the negative electrode sheet 122, and plays a bonding role.

[0114] The embodiments of the present application arrange the first part 11211 and the third part 11221, wherein the first part 11211 and the third part 11221 are both arranged between the base film 111 and the negative electrode sheet 122, and a polycarbosilane layer 14 is arranged on the surface of at least one of the first part 11211, the third part 11221 and the second sub-coating region 11232, so that the separators 11 and the separators 11, and the separators 11 and the electrode sheets 12 can be closely bonded together in the subsequent shaping process.

[0115] Optionally, the polycarbosilane layer 14 is distributed in a point-like manner on the surface of at least one of the first part 11211, the third part 11221 and the second sub-coating region 11232.

[0116] The polycarbosilane layer 14 here is a sheet-like structure and is arranged in a point-like manner on the surface of at least one of the first part 11211, the third part 11221 and the second sub-coating region 11232.

[0117] The embodiments of the present application distribute the polycarbosilane layer 14 in a point-like manner on the surface of at least one of the first part 11211, the third part 11221 and the second sub-coating region 11232, so that the bonding force can be provided by the point-like distributed polycarbosilane layer 14, and compared with the polycarbosilane layer 14 in a layered structure, the point-like distributed polycarbosilane layer 14 has a thinner thickness and lower cost.

[0118] Optionally, as shown in Figure 4 the second coating area 1122 further comprises a fourth part 11222, the fourth part 11222 and the third part 11221 are respectively arranged on opposite sides of the base film 111; a first turning area 16 is arranged at the connecting position of the third part 11221 and the second sub-coating area 11232; and / or a second turning area 17 is arranged at the connecting position of the fourth part 11222 and the first sub-coating area 11231.

[0119] It should be noted that the first turning area 16 herein can be an arc structure or a structure with an inflection point, and correspondingly, the second turning area 17 herein can be an arc structure or a structure with an inflection point.

[0120] The embodiments of the present application set the fourth part 11222, wherein the fourth part 11222 and the third part 11221 are respectively arranged on opposite sides of the base film 111, a first turning area 16 is arranged at the connecting position of the third part 11221 and the second sub-coating area 11232; and / or a second turning area 17 is arranged at the connecting position of the fourth part 11222 and the first sub-coating area 11231, so that the assembly of the negative electrode sheet 122 is facilitated through the first turning area 16, the assembly of the positive electrode sheet 121 is facilitated through the second turning area 17, the positive electrode sheet 121, the separator 11 and the negative electrode sheet 122 are assembled together according to the predetermined line, and the deviation can be better controlled and the probability of deviation of the positive electrode sheet 121 or the negative electrode sheet 122 is reduced.

[0121] Optionally, the first coating area 1121 further comprises a second part 11212, the second part 11212 and the first part 11211 are respectively arranged on opposite sides of the base film 111 along the second direction.

[0122] Optionally, as shown in Figure 3 the positive electrode sheet 121 and the negative electrode sheet 122 are respectively arranged on opposite sides of the base film 111 along the first direction, and the third coating area 1123 is arranged on the two sides of the electrode sheet 12 along the first direction.

[0123] That is, the number of the third coating area 1123 is two, wherein the upper third coating area 1123 is arranged flush with the upper edge of the base film 111 along the upper edge of the first direction, and the lower third coating area 1123 is arranged flush with the lower edge of the base film 111 along the lower edge of the first direction, so that the entire surface of the base film 111 in the first direction can be coated.

[0124] The edge strength of the separator 11 is improved, the probability of the separator 11 being bent and damaged is reduced, the separator 11 is not easily bent when being extruded, the tab is supported, the probability of the tab being inserted into the inside of the electrode assembly 1 and being internally short-circuited is reduced, the separator 11 is not exposed when being extruded, the probability of the tab 12 being corroded by contacting the shell is reduced, the thinned area 13 of the tab 12 can be closely attached, the dielectric strength detection result is more accurate, the probability of leakage is reduced, and the probability of lithium precipitation caused by the gap between the positive tab 121 and the negative tab 122 being increased due to the tab 12 being fluffy or the tab being bent and extruded is reduced.

[0125] Optionally, as shown in Figure 3 The negative tab 122 also includes a fourth film area 1223, the fourth film area 1223 and the second film area 1221 are respectively arranged on the opposite sides of the second foil 1222 along the second direction, and the second thinned area 132 is formed on the second film area 1221.

[0126] Optionally, the electrode assembly 1 also includes an insulating layer 15, wherein the insulating layer 15 is arranged at the edge position of the second foil 1222 along the first direction, and the second sub-coating area 11232 is arranged away from the insulating layer 15. The coating of the insulating layer 15 is to reduce the probability of the positive tab 121 and the negative tab 122 directly contacting and causing serious internal short-circuit consequences after the separator 11 is folded or pierced by the burr foreign matter on the end of the positive tab 121. Based on the present application, the edge coating thickness of the separator 11 is increased, which can well reduce the probability of the tab 12 piercing the separator 11 or the separator 11 being folded to cause the short circuit of the anode and the cathode. Alternatively, the present application can also cancel the insulating layer 15 and the corresponding part of the second foil 1222 to which the insulating layer 15 is attached, simplify the process operation, save the cost, and reduce the problem of poor fusion of the insulating layer 15 and the film area.

[0127] It should be noted that the coating layer 112 is arranged on the opposite sides of the base film 111 along the second direction. In the coating process, one surface of the base film 111 can be coated first, and then the other surface of the base film 111 can be coated. Alternatively, both surfaces of the base film 111 can be coated simultaneously in the coating process. After the coating is completed, the separator 11 is baked and heated to be solidified, so as to form the separator 11 with the edge strength being enhanced.

[0128] It should be noted that the edge strength of the separator 11 is improved, the probability of the separator 11 being bent and damaged is reduced, the separator 11 is not easily bent when being extruded, the tab is supported, the probability of the tab being inserted into the inside of the electrode assembly 1 and being internally short-circuited is reduced, the separator 11 is not exposed when being extruded, the probability of the tab 12 being corroded by contacting the shell is reduced, the thinned area 13 of the tab 12 can be closely attached, the dielectric strength detection result is more accurate, the probability of leakage is reduced, and the probability of lithium precipitation caused by the gap between the positive tab 121 and the negative tab 122 being increased due to the tab 12 being fluffy or the tab being bent and extruded is reduced.

[0129] The above description is only a summary of the technical solutions of the present application. In order to make the technical means of the present application clearer, the present application can be implemented according to the content of the description, and in order to make the above and other purposes, characteristics and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are described below.

[0130] A first aspect of embodiments of the present application provides a battery cell 10, the battery cell 10 comprising an electrode assembly 1, the electrode assembly 1 comprising a separator 11 and a pole piece 12, the pole piece 12 being provided on one side of the separator 11, and the pole piece 12 being provided with a thinned area 13 at an edge position in a first direction; the separator 11 comprising a base film 111 and a coating layer 112, the coating layer 112 being provided on a surface of at least one side of the base film 111 in a second direction, the coating layer 112 comprising a first coating area 1121 and a second coating area 1122, wherein the first coating area 1121 is respectively provided with the second coating area 1122 on both sides in the first direction, the second coating area 1122 is provided corresponding to the thinned area 13, and the thinned area 13 is provided with the second coating area 1122, and a surface of the coating layer 112 facing the pole piece 12 is provided in close contact with the pole piece 12; the first direction intersects the second direction, and the first direction is a height direction of the battery cell 10. Further, the coating layer 112 further comprises a third coating area 1123, the third coating area 1123 being provided on a side of the second coating area 1122 away from the first coating area 1121, and a minimum dimension of the third coating area 1123 in the second direction is greater than or equal to a maximum dimension of the second coating area 1122 in the second direction. Further, the dimensions of at least part of the third coating area 1123 in the second direction are consistent. Further, the number of the pole pieces 12 is two, and the two pole pieces 12 comprise a positive pole piece 121, the positive pole piece 121 comprising a first foil 1212 and a first film area 1211 connected in layers, the first film area 1211 being provided facing the base film 111, and the thinned area 13 comprises a first thinned area 131 provided on the first film area 1211; the third coating area 1123 comprises a first sub-coating area 11231, the first sub-coating area 11231 being provided on a side of the base film 111 facing the positive pole piece 121; in the second direction, the dimension of the first sub-coating area 11231 is greater than or equal to the maximum dimension of the first thinned area 131, and is less than or equal to the sum of the dimension of the first film area 1211 and the dimension of the first foil 1212. Further, the dimension of the first sub-coating area 11231 in the second direction is T, the maximum dimension of the first film area 1211 in the second direction is T1, the dimension of the first foil 1212 in the second direction is T2, the maximum dimension of the first thinned area 131 in the second direction is T3, and T3≤T≤T1+0.5*T2.Further, the two pole pieces 12 further include a negative pole piece 122, the negative pole piece 122 and the positive pole piece 121 are respectively arranged on opposite sides of the separator 11, the negative pole piece 122 includes a second foil 1222 and a second film area 1221 which are stacked and connected, the thinning area 13 further includes a second thinning area 132 arranged on the second film area 1221; the third coating area 1123 includes a second sub-coating area 11232, the second sub-coating area 11232 is arranged on a side of the base film 111 facing the negative pole piece 122; along the second direction, the size of the second sub-coating area 11232 is greater than or equal to the maximum size of the second thinning area 132, and is less than or equal to the sum of the size of the second film area 1221 and the size of the second foil 1222. Further, the size of the second sub-coating area 11232 along the second direction is T4, the maximum size of the second film area 1221 along the second direction is T6, the size of the second foil 1222 along the second direction is T7, the maximum size of the second thinning area 132 along the second direction is T5, T5≤T4≤T6+0.5*T7. Further, the first coating area 1121 includes a first part 11211, the second coating area 1122 includes a third part 11221, the first part 11211 and the third part 11221 are both arranged between the base film 111 and the negative pole piece 122; the surface of at least one of the first part 11211, the third part 11221 and the second sub-coating area 11232 is provided with a polycarbosilane layer 14. Further, the polycarbosilane layer 14 is distributed on the surface of at least one of the first part 11211, the third part 11221 and the second sub-coating area 11232 in a dotted manner. Further, the second coating area 1122 further includes a fourth part 11222, the fourth part 11222 and the third part 11221 are respectively arranged on opposite sides of the base film 111; the connecting position of the third part 11221 and the second sub-coating area 11232 is provided with a first turning area 16; and / or, the connecting position of the fourth part 11222 and the first sub-coating area 11231 is provided with a second turning area 17. Further, the pole piece 12 is provided with the third coating area 1123 on both sides along the first direction, and the edges of the third coating area 1123 along the first direction are flush with the corresponding edges of the base film 111.

[0131] The above merely describes a preferred specific embodiment of the present application, but the protection scope of the present application is not limited to this. Any changes or replacements within the technical scope disclosed by the present application can be easily thought of by those skilled in the art, and should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A battery cell, characterized in that, include: An electrode assembly, comprising a diaphragm, an electrode sheet, and an insulating layer, wherein the electrode sheet is disposed on one side of the diaphragm, and the electrode sheet has a thinning area at its edge along a first direction; The diaphragm includes a base film and a coating layer. The coating layer is disposed on at least one side of the surface of the base film along a second direction. The coating layer includes a first coating area, a second coating area, and a third coating area. The second coating area is disposed on both sides of the first coating area along the first direction. The second coating area is disposed corresponding to the thinning area and is disposed within the thinning area. The third coating area is disposed on the side of the second coating area away from the first coating area. The third coating area protrudes from the corresponding edge of the electrode sheet along the first direction. The coating layer is disposed facing the surface of the electrode sheet and is attached to the electrode sheet. The number of electrodes is two, and the two electrodes include a positive electrode and a negative electrode. The negative electrode and the positive electrode are respectively disposed on opposite sides of the separator. The positive electrode includes a first foil and a first film region stacked and connected together. The first film region is disposed facing the base film. The thinning region includes a first thinning region disposed on the first film region. The third coating region includes a first sub-coating region, which is located on the side of the base film facing the positive electrode sheet; The negative electrode sheet includes a second foil and a second film region stacked and connected together, and the thinning region includes a second thinning region disposed on the second film region facing the base film; The third coating region includes a second sub-coating region, which is located on the side of the base film facing the negative electrode sheet; The insulating layer is disposed at the edge of the second foil along the first direction, and the second sub-coating area is disposed away from the insulating layer; Along the second direction, the size of the first sub-coating region is greater than or equal to the maximum size of the first thinning region, and less than or equal to the sum of the size of the first film region and the size of the first foil. The first coating area includes a first portion, and the second coating area includes a third portion, wherein both the first portion and the third portion are disposed between the base film and the negative electrode sheet; A polycarbosilane layer is provided on the surface of at least one of the first part, the third part, and the second sub-coating region; the polycarbosilane layer is distributed in a dotted manner on the surface of at least one of the first part, the third part, and the second sub-coating region, and the polycarbosilane layer has a sheet-like structure. The first direction intersects with the second direction, and the first direction is the height direction of the battery cell.

2. The battery cell as described in claim 1, characterized in that, The minimum dimension of the third coating region along the second direction is greater than or equal to the maximum dimension of the second coating region along the second direction.

3. The battery cell as described in claim 2, characterized in that, At least a portion of the third coating region has a consistent dimension along the second direction.

4. The battery cell as described in claim 1, characterized in that, in, The dimension of the first sub-coating area along the second direction is T, the maximum dimension of the first film area along the second direction is T1, the dimension of the first foil material along the second direction is T2, the maximum dimension of the first thinning area along the second direction is T3, and T3≤T≤T1+0.5*T2.

5. The battery cell as described in claim 3, characterized in that, Along the second direction, the size of the second sub-coating region is greater than or equal to the maximum size of the second thinning region, and less than or equal to the sum of the size of the second film region and the size of the second foil.

6. The battery cell as described in claim 5, characterized in that, The second sub-coating area has a dimension of T4 along the second direction, the second film area has a maximum dimension of T6 along the second direction, the second foil has a dimension of T7 along the second direction, and the second thinning area has a maximum dimension of T5 along the second direction, where T5≤T4≤T6+0.5*T7.

7. The battery cell as described in claim 1, characterized in that, The second coating area further includes a fourth portion, wherein the fourth portion and the third portion are respectively disposed on opposite sides of the base film; The connection between the third part and the second sub-coating area is provided with a first turning area; and / or, the connection between the fourth part and the first sub-coating area is provided with a second turning area.

8. The battery cell according to any one of claims 2 to 7, characterized in that, The electrode sheet has a third coating area on each side along the first direction, and the edge of the third coating area along the first direction is flush with the corresponding edge of the base film.

9. A battery device, characterized in that, The battery device includes: The battery cell as described in any one of claims 1 to 8; and The battery cell is housed within the housing.

10. An electrical appliance, characterized in that, The electrical equipment includes a battery cell as described in any one of claims 1 to 8.

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