Current collector, battery monomer, battery device and power utilization device

Abstract

The invention belongs to the technical field of batteries, and particularly discloses a current collector, a battery monomer, a battery device and a power utilization device. The current collector comprises an insulating base layer, and the insulating base layer comprises a first main body region and an edge region located on the outer side of the first main body region; a compression modulus of the first body region of the insulating base layer is less than a compression modulus of the edge region of the insulating base layer. According to the design mode provided by the invention, the cycle service life of the battery is prolonged by relieving the expansion of the pole piece in the charging and discharging process of the battery.

Description

Technical Field

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

[0002] With the development of new energy technology, batteries are used more and more widely, such as in mobile phones, laptops, battery cars, electric cars, energy storage devices, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes and electric tools, etc. This places higher and higher requirements on battery performance. Summary of the invention

[0003] The present application provides a current collector and a battery cell, a battery device and an electric device. The battery cell improves the cycle life of the battery by alleviating the expansion of the pole piece during the battery charging and discharging process.

[0004] In a first aspect, the present application provides a battery cell, the battery cell comprising a current collector and an active material layer located on at least one side surface of the current collector;

[0005] The current collector includes an insulating base layer, the insulating base layer includes a first main region and an edge region located outside the first main region; the compression modulus of the first main region of the insulating base layer is smaller than the compression modulus of the edge region of the insulating base layer;

[0006] The current collector further comprises a conductive layer, and the conductive layer is located between the insulating base layer and the active material layer.

[0007] In some embodiments, the compression modulus of the first main region of the insulating base layer is Q1, and the compression modulus of the edge region of the insulating base layer is Q2;

[0008] Satisfies: Q2 / Q1=1.20~2.25.

[0009] The battery of the present application expands the electrode during the charge and discharge process. Since the expansion degree of the electrode main area corresponding to the main area of ​​the current collector is more obvious than the expansion degree of the electrode edge area, the first main area of ​​the insulating base layer of the current collector is subjected to greater pressure from the electrode than the edge area of ​​the insulating base layer. The present application selects a compression modulus of the first main area of ​​the insulating base layer that is smaller than the compression modulus of the edge area, that is, the volume change degree of the first main area of ​​the insulating base layer is greater than the volume change degree of the edge area, which has a buffering effect on the expansion of the electrode to a certain extent, thereby improving the cycle life of the battery by alleviating the expansion of the electrode.

[0010] In some embodiments, the compression modulus of the first main region of the insulating base layer is Q1, and Q1 is 0.8 GPa to 2.8 GPa;

[0011] and / or;

[0012] The compression modulus of the edge area of ​​the above-mentioned insulating base layer is Q2, and Q2 is 1.8GPa to 3.4GPa.

[0013] In some embodiments, the porosity of the first main region of the insulating base layer is greater than the porosity of the edge region of the insulating base layer.

[0014] In some embodiments, the porosity of the first main region of the insulating base layer is 10% to 40%;

[0015] and / or;

[0016] The porosity of the edge area of ​​the above-mentioned insulating base layer is 0-20%.

[0017] In some embodiments, the insulating base layer includes a first edge region and a second edge region, the first edge region and the second edge region extend along the first direction and are arranged in the second direction, and the first main region is disposed between the first edge region and the second edge region;

[0018] The first direction intersects with the second direction;

[0019] The compression modulus of the first main body region is 1.25 GPa to 2.50 GPa;

[0020] and / or;

[0021] The porosity of the first main body region is 10% to 35%;

[0022] and / or;

[0023] The compression modulus of the first edge region and the second edge region are independently selected from 2.0 GPa to 3.3 GPa;

[0024] and / or;

[0025] The porosity of the first edge region and the second edge region are independently selected from 2.5% to 20%.

[0026] In some embodiments, along the second direction, the first edge region includes an A surface and a B surface that are oppositely disposed, and a distance between the A surface and the B surface is W1;

[0027] Along the second direction, the first main body region includes a C surface and a D surface that are oppositely disposed, and a distance between the C surface and the D surface is W2;

[0028] Along the second direction, the second edge region includes an A' surface and a B' surface that are oppositely disposed, and a distance between the A' surface and the B' surface is W3;

[0029] Satisfies: W2:W1:W3=1~3:1~2:1~2.

[0030] In some embodiments, the conductive layer includes a second main body region, and the second main body region is provided with a through hole;

[0031] The orthographic projection of the second main body region on the insulating base layer at least partially overlaps with the first main body region.

[0032] In some embodiments, the conductive layer includes a second main region and an edge region located outside the second main region;

[0033] The second main region of the conductive layer is provided with a through hole, and the edge region of the conductive layer is not provided with a hole.

[0034] In some embodiments, the average pore diameter of the through holes is 100 nm to 10 μm.

[0035] In some embodiments, the conductive layer includes a third edge region and a fourth edge region, the third edge region and the fourth edge region extend along the first direction and are arranged in the second direction, and the second main region is disposed between the third edge region and the fourth edge region;

[0036] The first direction intersects with the second direction;

[0037] The second main body region of the conductive layer is provided with through holes, and the average pore diameter of the through holes is 200 nm to 6 μm;

[0038] The third edge region and the fourth edge region of the conductive layer are not provided with holes.

[0039] In some embodiments, along the second direction, the third edge region includes an E surface and an F surface that are oppositely disposed, and a distance between the E surface and the F surface is T1;

[0040] Along the second direction, the second main body region includes a G surface and an H surface that are oppositely arranged, and a distance between the G surface and the H surface is T2;

[0041] Along the second direction, the fourth edge region includes an E' surface and an F' surface that are oppositely disposed, and a distance between the E' surface and the F' surface is T3;

[0042] Satisfies: T2:T1:T3=1~3:1~2:1~2.

[0043] In some embodiments, the material of the insulating base layer includes any one or more of polyester terephthalate, polyethylene, polypropylene, epoxy resin, polyamide, polyimide, polyester, polyolefin, polyacetylene, siloxane polymer, polyether, polyol, polysulfone, polysaccharide polymer, amino acid polymer, polysulfur nitride polymer, and aromatic ring polymer;

[0044] and / or;

[0045] The conductive layer includes metal, and the metal includes any one or more of aluminum, aluminum alloy, copper, copper alloy, nickel, nickel alloy, iron, iron alloy, titanium, titanium alloy, silver and silver alloy.

[0046] In some embodiments, the insulating base layer and the conductive layer extend along a first direction and are stacked in a third direction;

[0047] The first direction intersects with the third direction;

[0048] Along the third direction, the thickness of the insulating base layer is 25 μm to 50 μm;

[0049] and / or;

[0050] Along the third direction, the thickness of the conductive layer is 3 μm to 10 μm.

[0051] In some embodiments, the current collector and the active material layer extend along a first direction and are stacked in a third direction;

[0052] The first direction intersects with the third direction;

[0053] Along the third direction, the active material layer includes an M surface and an N surface that are arranged opposite to each other, the M surface is arranged close to the current collector, and the distance between the M surface and the N surface is H;

[0054] The region extending from the M surface to 0.1×H is recorded as the first region, and the region extending from the N surface to 0.1×T1 is recorded as the second region;

[0055] The first region includes a first active material, and the second region includes a second active material;

[0056] The median particle size of the first active material is smaller than the median particle size of the second active material.

[0057] In some embodiments, the current collector and the active material layer extend along a first direction and are stacked in a third direction;

[0058] The first direction intersects with the third direction;

[0059] Along the third direction, the active material layer includes a first active material layer disposed close to the current collector and a second active material layer disposed on a surface of the first active material layer away from the current collector;

[0060] The first active material layer includes a first active material, and the second active material layer includes a second active material;

[0061] The median particle size of the first active material is smaller than the median particle size of the second active material.

[0062] A second aspect of the present application is to provide a current collector, the current collector comprising an insulating substrate;

[0063] The insulating base layer comprises a first main region and an edge region located outside the first main region; the compression modulus of the first main region of the insulating base layer is smaller than the compression modulus of the edge region of the insulating base layer;

[0064] The current collector further comprises a conductive layer, and the conductive layer is located between the insulating base layer and the active material layer.

[0065] A third aspect of the present application is to provide a battery device, which includes the battery cell described in the first aspect or the current collector described in the second aspect.

[0066] A fourth aspect of the present application is to provide an electrical device, which includes the battery device described in the third aspect.

[0067] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0069] Figure 1 A schematic diagram of the battery structure of some embodiments of the present application;

[0070] Figure 2 This is a schematic diagram of the exploded structure of batteries in some embodiments of the present application;

[0071] Figure 3 A schematic diagram of a vehicle structure of some embodiments of the present application;

[0072] Figure 4 A schematic diagram of the structure of a battery pack according to some embodiments of the present application;

[0073] FIG5 is a schematic diagram of the structure of the current collector in some embodiments of the present application; wherein, Figure 5AA structural schematic diagram illustrating the positional relationship between the conductive layer and the insulating base layer;

[0074] Figure 5B , Figure 5C , Figure 5D and Figure 5E They are schematic diagrams of specific structures with different positional relationships between the second main region of the conductive layer and the first main region of the insulating base layer;

[0075] FIG6 is a schematic diagram of the structure of the insulating base layer of the current collector in some embodiments of the present application; wherein, Fig. 6A , Figure 6B , Figure 6C It is a schematic diagram of the structure of the insulating base layer including different areas;

[0076] FIG. 7 is a schematic diagram of the structure of the conductive layer of the current collector of some embodiments of the present application; wherein, Fig. 7A , Figure 7B is a schematic diagram of the structure of a conductive layer including different regions;

[0077] Figure 8 A schematic diagram of the structure of a secondary battery in some embodiments of the present application;

[0078] FIG9 is a schematic diagram of the structure of the negative electrode sheet in some embodiments of the present application; wherein, Fig.9A , Fig. 9B Mainly used to illustrate different areas of the negative electrode;

[0079] Fig.10 This is a schematic diagram of the structure of the electrode plates of some embodiments of the present application.

[0080] The reference numerals in the specific implementation manner are as follows:

[0081] 10000, vehicles;

[0082] 1000, battery; 2000, controller; 3000, motor;

[0083] 100. Battery cell;

[0084] 200, box body; 210, first part; 220, second part;

[0085] 10. Secondary battery;

[0086] 101, housing; 102, electrode assembly; 103, cover plate;

[0087] 1. Negative electrode sheet; 11. Negative electrode active material layer;

[0088] M surface, N surface: surfaces of the negative electrode active material layer arranged opposite to each other along the third direction;

[0089] 11A, first region; 11B, second region; 11a, first negative electrode active material layer; 11b, second negative electrode active material layer;

[0090] 2. positive electrode plate; 21. positive electrode active material layer;

[0091] 3. Isolation parts;

[0092] 4. Current collector; 41. Insulating base layer; 411. First main region; 412. Edge region of insulating base layer; 412a. First edge region; 412b. Second edge region;

[0093] Surface A and Surface B: surfaces of the first edge region that are arranged opposite to each other along the second direction;

[0094] Surface C and Surface D: surfaces of the first main body area that are arranged opposite to each other along the second direction;

[0095] A' surface, B' surface: surfaces of the second edge region arranged opposite to each other along the second direction;

[0096] 42, conductive layer; 421, second main region; 422, edge region of the conductive layer; 422a, third edge region; 422b, fourth edge region;

[0097] Surface E and Surface F: surfaces of the third edge region arranged opposite to each other along the second direction;

[0098] G surface, H surface: surfaces of the second main body region arranged opposite to each other along the second direction;

[0099] E' surface and F' surface: surfaces of the fourth edge region arranged opposite to each other along the second direction;

[0100] First direction: the extension direction of the current collector, also referred to as the length direction of the current collector or the coordinate axis x direction;

[0101] Second direction: also refers to the width direction of the current collector or the coordinate axis y direction;

[0102] The third direction also refers to the thickness direction or stacking direction of the current collector or the coordinate axis z direction. DETAILED DESCRIPTION

[0103] Below, the embodiments of the current collector and battery cell, battery device and electrical device of the present application are specifically disclosed in detail with appropriate reference to the drawings. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there are cases where detailed descriptions of well-known matters and repeated descriptions of actually the same structure are omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the drawings and the following description are provided for those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0104] The "range" disclosed in the present application is defined in the form of a lower limit and an upper limit, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of the particular range. The range defined in this way can be inclusive or exclusive of the end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range. For example, if a range of 60 to 120 and 80 to 110 is listed for a particular parameter, it is understood that a range of 60 to 110 and 80 to 120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following ranges can all be expected: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4 and 2 to 5. In the present application, unless otherwise specified, the numerical range "a to b" represents an abbreviation of any real number combination between a and b, where a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0105] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0106] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0107] If there is no special explanation, all steps of the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0108] If there is no special explanation, the "include" and "comprising" mentioned in this application are open-ended or closed-ended. For example, the "include" and "comprising" may mean that other components not listed may also be included or only the listed components may be included or only the listed components may be included.

[0109] If not specifically stated, in this application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0110] If not otherwise specified, in this application, the 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 quantity, specific order or primary and secondary relationship of the indicated technical features.

[0111] Unless otherwise specified, in this application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple sheets" refers to more than two sheets (including two sheets).

[0112] Unless otherwise specified, the orientations or positional relationships indicated by technical terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", and "circumferential" are based on the orientations or positional relationships shown in the accompanying 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 referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the embodiments of the present application.

[0113] Batteries have been widely used in various products due to their high energy density, long cycle life, safety and reliability. In recent years, as the demand for batteries as energy has increased significantly, higher requirements have been placed on battery performance, such as cycle life.

[0114] During the charge and discharge cycle of the battery, some irreversible reactions will occur while the positive and negative electrode materials are being released and embedded. The products of these reactions are deposited on the surface of the electrode as insoluble byproducts, which can easily cause irreversible expansion of the battery. When the battery cell is packaged, the size of the battery cell and the battery cell shell are properly matched with each other, for example, the thickness will be within a certain tolerance range, and the above-mentioned irreversible expansion will inevitably lead to the expansion of the battery cell. When this expansion is subjected to stress from the battery cell shell, it will squeeze the electrolyte in the electrode and the separator. The squeezed electrolyte is difficult to flow back into the electrode even during the battery discharge process, which will inevitably affect the electrode's infiltration of the electrolyte, causing the battery's cycle performance to decay rapidly and ultimately affecting the battery's life.

[0115] Based on the above considerations, in order to improve the cycle life of the battery, the present application conducted relevant experimental research and obtained a current collector and a battery cell, a battery device and an electrical device.

[0116] First, the present application discloses a battery cell, which includes a current collector and an active material layer located on at least one side of the current collector; the current collector includes an insulating base layer, the insulating base layer includes a first main region, and an edge region located outside the first main region; the compression modulus of the first main region of the insulating base layer is smaller than the compression modulus of the edge region of the insulating base layer; the current collector also includes a conductive layer, which is located between the insulating base layer and the active material layer.

[0117] The battery of the present application expands the electrode during the charge and discharge process. Since the expansion degree of the electrode main area corresponding to the main area of ​​the current collector is more obvious than the expansion degree of the electrode edge area, the first main area of ​​the insulating base layer of the current collector is subjected to greater pressure from the electrode than the edge area of ​​the insulating base layer. The present application selects a compression modulus of the first main area of ​​the insulating base layer that is smaller than the compression modulus of the edge area, that is, the volume change degree of the first main area of ​​the insulating base layer is greater than the volume change degree of the edge area, which has a buffering effect on the expansion of the electrode to a certain extent, thereby improving the cycle life of the battery by alleviating the expansion of the electrode.

[0118] Therefore, the battery cell provided in this application is helpful to improve user experience.

[0119] Electrode assembly

[0120] A battery cell generally includes an electrode assembly. The electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separator, which is arranged between the negative electrode sheet and the positive electrode sheet. During the charge and discharge process of the battery cell, active ions (such as lithium ions) are embedded and removed back and forth between the positive electrode sheet and the negative electrode sheet. The separator is arranged between the positive electrode sheet and the negative electrode sheet, which can prevent the positive and negative electrodes from short-circuiting, and at the same time allow active ions to pass through.

[0121] Battery device

[0122] The battery apparatus mentioned in the embodiments of the present application may include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly may include multiple battery cells, which are connected in series, in parallel or in mixed connection through a busbar component.

[0123] In some embodiments, a battery cell assembly is generally formed by arranging a plurality of battery cells.

[0124] As an example, the battery cell assembly may be a battery module, which is formed by arranging and fixing a plurality of battery cells to form an independent module. As an example, the battery module may be formed by bundling a plurality of battery cells by a cable tie.

[0125] In some embodiments, the battery device may be a battery pack, which includes a case and one or more battery cell assemblies, wherein the battery cell assemblies are accommodated in the case.

[0126] As an example, the battery cell assembly may be a battery module, and the battery cell assembly may be accommodated in the box by fixing the battery module in the box.

[0127] As an example, the battery cell assembly may also be housed in the case by directly fixing a plurality of battery cells to the case.

[0128] As an example, the box may include a first box and a second box. The first box and the second box are buckled together to form a closed space inside the box to accommodate the battery cell assembly. The closed here means covered or closed, which can be sealed or unsealed. The first box can be a top cover or a bottom plate.

[0129] As an example, the box body may include a top cover, a frame and a bottom plate. The top cover and the bottom plate are respectively connected to the frame, so that a closed space is formed inside the box body to accommodate the battery cell assembly.

[0130] In some embodiments, the box body can be used as a part of the chassis structure of the vehicle. For example, part of the box body can become at least a part of the floor of the vehicle, or part of the box body can become at least a part of the cross beam and longitudinal beam of the vehicle.

[0131] The battery cell of the present application may include an outer packaging. The outer packaging may be used to encapsulate the electrode assembly and electrolyte composed of the above-mentioned battery cell. The outer packaging of the battery cell may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc. The outer packaging of the battery cell may also be a soft package, such as a bag-type soft package. The material of the soft package may be plastic, and the plastic includes but is not limited to polypropylene, polybutylene terephthalate, and polybutylene succinate, etc.

[0132] The present application has no particular limitation on the shape of the battery, which may be cylindrical, square or any other shape. For example, Figure 1 The secondary battery 10 is a square structure as an example.

[0133] According to some embodiments of the present application, Figure 2, the outer packaging may include a shell 101 and a cover plate 103. Among them, the shell 101 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity. The shell 101 has an opening connected to the receiving cavity, and the cover plate 103 can be covered on the opening to close the receiving cavity. The positive electrode sheet, the negative electrode sheet and the isolation film can form an electrode assembly 102 through a winding process or a lamination process. The electrode assembly 102 is encapsulated in the receiving cavity. The electrolyte is infiltrated in the electrode assembly 102. The number of electrode assemblies 102 contained in the secondary battery 10 can be one or more, and those skilled in the art can select according to specific actual needs.

[0134] The electrode assembly 102 provided in the present application is applied to a battery cell, which is beneficial to improving the performance of the battery cell. The battery cell can be used as a power source for an electrical device or as an energy storage unit for an electrical device. The electrical device is applied to the power field, such as mobile devices (such as mobile phones, laptop computers, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but not limited to the above-mentioned fields.

[0135] For the convenience of explanation, some embodiments of the present application are described by taking a vehicle as an example of an electrical device.

[0136] Please refer to Figure 3 , Figure 3 A schematic diagram of the structure of a vehicle 10000 provided for some embodiments of the present application. The vehicle 10000 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 1000 is provided inside the vehicle 10000, and the battery 1000 may be provided at the bottom, head or tail of the vehicle 10000. The battery 1000 may be used to power the vehicle 10000, for example, the battery 1000 may be used as an operating power source for the vehicle 10000. The vehicle 10000 may also include a controller 2000 and a motor 3000, and the controller 2000 is used to control the battery 1000 to power the motor 3000, for example, for the starting, navigation and working power requirements of the vehicle 10000 during driving.

[0137] In some embodiments of the present application, the battery 1000 can not only serve as the operating power source of the vehicle 10000, but also serve as the driving power source of the vehicle 10000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 10000.

[0138] Please refer to Figure 4 , Figure 4An exploded view of a battery 1000 provided in some embodiments of the present application. The battery 1000 includes a housing 200 and a battery cell 100. Conventional battery cells include primary batteries or secondary batteries. The present application specifically protects secondary batteries 10. The battery cell 100 is accommodated in the housing 200. The housing 200 is used to provide a storage space for the battery cell 100. The housing 200 can adopt a variety of structures.

[0139] In some embodiments, the box 200 may include a first portion 210 and a second portion 220, the first portion 210 and the second portion 220 cover each other, and the first portion 210 and the second portion 220 jointly define a storage space for accommodating the battery cell 100. The second portion 220 may be a hollow structure with one end open, and the first portion 210 may be a plate-like structure, and the first portion 210 covers the open side of the second portion 220, so that the first portion 210 and the second portion 220 jointly define a storage space; the first portion 210 and the second portion 220 may also be hollow structures with one side open, and the open side of the first portion 210 covers the open side of the second portion 220. Of course, the box 200 formed by the first portion 210 and the second portion 220 may be in various shapes, such as a cylinder, a cuboid, etc.

[0140] In the battery 1000, there may be multiple battery cells 100, and the multiple battery cells 100 may be connected in series, in parallel, or in a mixed connection. A mixed connection means that the multiple battery cells 100 are both connected in series and in parallel. The multiple battery cells 100 may be directly connected in series, in parallel, or in a mixed connection, and then the whole formed by the multiple battery cells 100 is accommodated in the box 200; of course, the battery 1000 may also be a battery 1000 module formed by connecting multiple battery cells 100 in series, in parallel, or in a mixed connection, and then the multiple battery 1000 modules are connected in series, in parallel, or in a mixed connection to form a whole, and accommodated in the box 200. The battery 1000 may also include other structures, for example, the battery 1000 may also include a busbar component for realizing electrical connection between the multiple battery cells 100.

[0141] Battery Cell

[0142] In some embodiments, the present application discloses a battery cell, which includes a current collector and an active material layer located on at least one side of the current collector; the current collector includes an insulating base layer, the insulating base layer includes a first main region, and an edge region located outside the first main region; the compression modulus of the first main region of the insulating base layer is smaller than the compression modulus of the edge region of the insulating base layer, and the current collector also includes a conductive layer, which is located between the insulating base layer and the active material layer.

[0143] The battery cell of the present application may be a secondary battery, which refers to a battery cell that can be used continuously by activating the active material by charging after the battery cell is discharged. The battery cell may be a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel hydrogen battery, a nickel cadmium battery, a lead storage battery, etc., and the embodiments of the present application are not limited thereto.

[0144] The current collector of the present application refers to a structure or component for collecting current, which can collect the current generated by the active material of the battery to form a larger current for external output, and at the same time, its own internal resistance is small enough.

[0145] The insulating base layer of the present application refers to a film layer made of organic insulating polymer material that supports the conductive layer and the active material layer. The insulating base layer can firstly effectively absorb the deformation stress caused by the expansion of the pole piece. Secondly, in the case of a short circuit, the insulating base layer can also provide a larger resistance, reduce the short-circuit current, prevent thermal runaway, and thus improve the safety of the battery.

[0146] The conductive layer of the present application refers to a film layer with conductive ability, and the conductive layer can collect the current generated by the active material of the battery to form a larger current for external output.

[0147] like Figure 5A , 5B , 5C, 5D, and 5E indicate that the current collector 4 of the present application includes an insulating base layer 41 and a conductive layer 42, wherein the conductive layer 42 is located on at least one side surface of the insulating base layer 41. Figures 5A to 5D It is only shown that the conductive layer 42 is arranged on one side of the insulating base layer 41. The battery cell actually discussed in the subsequent specific embodiments of this application includes the insulating base layer 41 and the conductive layers 42 located on the two side surfaces of the insulating base layer 41, which will be discussed in detail later in this application.

[0148] This application Fig. 6A , Figure 6B and Figure 6C The schematic diagram of the partial structure of the insulating base layer 41 is shown; Fig. 7A , Figure 7B A partial structural schematic diagram of the conductive layer 42 is shown.

[0149] Combination FIG. 6A to FIG. 6C It can be seen that the insulating base layer 41 includes a first main body region 411 and an edge region 412 of the insulating base layer located outside the first main body region 411. Fig. 6A , Figure 6BIt can be seen that the first main area 411 is located in the central position of the insulating base layer 41, and the edge area 412 of the insulating base layer is located in the peripheral area of ​​the first main area 411 and arranged circumferentially along the first main area 411. The positive projection shape of the first main area 411 on the insulating base layer 41 includes any shape conventional in the art, such as a regular circle, ellipse, square, or various irregular shapes. Figure 6B Only some structures and shapes are shown in the figure. Figure 6C It can be known that the edge region 412 of the insulating base layer and the first main region 411 extend along the coordinate axis x direction and are arranged along the coordinate axis y direction. This application will describe the positional relationship in detail below.

[0150] The compression modulus of the present application is a measure of the material's ability to resist deformation when subjected to a compressive force. Generally speaking, the larger the value of the compression modulus, the smaller the volume change of the material when under pressure, and the better the stability and deformation resistance. Conversely, the smaller the value of the compression modulus, the greater the volume change of the material when under pressure. The method for determining the compression modulus of the insulating base layer of the present application includes any conventional method in the field, such as first obtaining the insulating base layer of the current collector, and the specific steps are as follows: placing the battery cell in a 1.0 mol / L sodium hydroxide aqueous solution at room temperature for discharge treatment, and after the discharge is completed, manually disassembling to obtain the pole piece and the separator;

[0151] A cryo-focused ion beam (FIB) is used to slice the electrode layer by layer at different thickness positions (the smallest scale can reach nanoscale slices) to separate the insulating base layer and the conductive layer. Different areas of the insulating base layer are then cut to obtain the first main area sample and the edge area sample.

[0152] Then, the test is carried out according to the national standard GB / T 1041-2008 / ISO 604:2002 on the test of plastic compression properties:

[0153] (1) Specimen preparation: Specimen type and size: According to the standard requirements, the size and shape of the specimen must comply with the regulations: specimen length 50±2mm, width 10±0.2mm, thickness 4±0.2mm (obtain the corresponding thickness by stacking multiple layers).

[0154] (2) Sample processing: The sample should be prepared by mechanical processing to avoid mechanical damage such as delamination, scratches and local extrusion. After processing, it should be dried under appropriate conditions.

[0155] (3) Testing equipment: universal material testing machine.

[0156] (4) Specimen size measurement: Use a vernier caliper to measure the width and thickness of the specimen along its length.

[0157] (5) Specimen installation: Install the specimen in the compression fixture of the universal material testing machine to ensure that the specimen does not slip or twist during the compression process.

[0158] (6) Setting test parameters: Set the compression speed of the testing machine to a constant 1 mm / min.

[0159] (7) Start the test: Start the testing machine to perform compression and record the force-displacement data during the test until the specified compression ratio is reached or the specimen is destroyed.

[0160] (8) Data recording: record the maximum force value, corresponding displacement and other data during the compression process.

[0161] (9) Calculation of compression modulus: Compression modulus refers to the ratio of compression stress to compression strain within the linear range of the stress-strain curve. The unit is MPa. Calculation method: By drawing the compression load-strain curve, selecting the load and deformation data of at least 5 points in the linear region, and calculating the ratio of stress to strain, the compression modulus is obtained.

[0162] The compression modulus of the first main area 411 of the insulating base layer 41 of the present application is less than the compression modulus of the edge area 412 of the insulating base layer. This is because the battery of the present application undergoes expansion of the pole piece during the charge and discharge process, and since the expansion degree of the pole piece main area corresponding to the main area of ​​the current collector is more obvious than the expansion degree of the pole piece edge area, the first main area 411 of the insulating base layer 41 of the current collector 4 is subjected to greater pressure from the pole piece than the edge area 412 of the insulating base layer. The present application adopts the above-mentioned design method to make the volume change degree of the first main area 411 of the insulating base layer 41 greater than the volume change degree of the edge area, which plays a buffering role on the expansion of the pole piece to a certain extent, thereby improving the cycle life of the battery by relieving the expansion of the pole piece.

[0163] In some embodiments, the compression modulus of the first main region 411 of the insulating base layer 41 is Q1, and the compression modulus of the edge region 412 of the insulating base layer is Q2;

[0164] Satisfies: Q2 / Q1=1.20~2.25.

[0165] As described above, the battery of the present application expands the electrode during the charge and discharge process, and the expansion exerts pressure on the entire current collector. The first main area 411 of the insulating base layer 41 of the current collector 4 is subjected to greater pressure from the electrode than the edge area 412 of the insulating base layer. Therefore, the present application chooses to control the ratio of the compression modulus of the edge area 412 of the insulating base layer to the compression modulus of the first main area 411 of the insulating base layer 41 within a certain numerical range, so as to facilitate the buffering effect on the expansion of the electrode.

[0166] In these embodiments, the present application discloses that Q2 / Q1 is any one of 1.20, 1.21, 1.25, 1.30, 1.35, 1.40, 1.45, 1.50, 1.55, 1.60, 1.65, 1.70, 1.75, 1.80, 1.85, 1.90, 1.95, 2.00, 2.05, 2.10, 2.15, 2.20, and 2.25, or any one of the values ​​satisfying any two ranges above.

[0167] In some embodiments, the compression modulus of the first main region of the insulating base layer is Q1, and Q1 is 0.8 GPa to 2.8 GPa.

[0168] In some embodiments, the compression modulus of the edge region of the insulating base layer is Q2, and Q2 is 1.8 GPa to 3.4 GPa.

[0169] The first main region 411 of the insulating base layer 41 of the current collector 4 of the present application and the edge region 412 of the insulating base layer each have a certain compression modulus. The present application discloses a specific numerical range of each compression modulus in these embodiments. Within this numerical range, it is convenient to buffer the expansion of the electrode piece, and it can also increase the matching between the current collector and the electrode piece, thereby reducing the probability of thermal runaway of the battery.

[0170] In these embodiments, the present application discloses that the compression modulus Q1 of the first main region of the insulating base layer is any one of 0.8 GPa, 0.9 GPa, 1.0 GPa, 1.1 GPa, 1.2 GPa, 1.3 GPa, 1.4 GPa, 1.5 GPa, 1.6 GPa, 1.7 GPa, 1.8 GPa, 1.9 GPa, 2.0 GPa, 2.1 GPa, 2.2 GPa, 2.3 GPa, 2.4 GPa, 2.5 GPa, 2.6 GPa, 2.7 GPa, and 2.8 GPa, or any one of the values ​​satisfying any two of the above ranges.

[0171] In these embodiments, the present application discloses that the compression modulus Q2 of the edge zone of the insulating base layer is any one of 1.8 GPa, 1.9 GPa, 2.0 GPa, 2.1 GPa, 2.2 GPa, 2.3 GPa, 2.4 GPa, 2.5 GPa, 2.6 GPa, 2.7 GPa, 2.8 GPa, 2.9 GPa, 3.0 GPa, 3.1 GPa, 3.2 GPa, 3.3 GPa, and 3.4 GPa, or any one of the values ​​satisfying any two of the above ranges.

[0172] In some embodiments, the porosity of the first main region 411 of the insulating base layer 41 is greater than the porosity of the edge region 412 of the insulating base layer.

[0173] The porosity of the present application refers to the percentage of the pore volume in the material to the total volume of the material in its natural state. The size of the porosity is affected by the porous shape, structure and arrangement of the material, and the porosity of the material affects the fluid transmission performance in the porous medium and the mechanical properties of the material. Generally speaking, the greater the porosity, the more fluid is absorbed in the material, the faster the fluid transmission speed is, and the strength or compression modulus of the material decreases. The method for determining the porosity of the present application includes any conventional method in the art, such as cutting each film layer sample after drying into a square specimen of about 20mm×20mm, measuring the thickness and actual side length by a digital micrometer and a vernier caliper, calculating its volume as V, and weighing its weight M0, then immersing the square specimen in n-hexadecane reagent, taking it out after soaking it for 2h at room temperature and air atmosphere, absorbing the n-hexadecane reagent liquid adsorbed on the surface, and then weighing its weight M t , then the porosity of each membrane layer satisfies the following mathematical relationship:

[0174] Porosity = (M t -M0) / ρ×V×100%;

[0175] The ρ in the above mathematical relationship is the density of the n-hexadecane reagent, in g / mm 3 , V is the volume of the square sample of each film layer, in mm 3 , weight M0 and M t The unit is g, the weight measuring instrument is a thousandth balance, and the models of the thousandth balance, digital display micrometer, and vernier caliper include but are not limited to any conventional models in the art.

[0176] In these embodiments, the present application selects a porosity of the first main region 411 of the insulating base layer 41 that is greater than the porosity of the edge region of the insulating base layer 412, so that the electrolyte can fully infiltrate the first main region 411 of the edge region of the insulating base layer 41, and the electrolyte in the first main region 411 of the insulating base layer 41 flows toward the electrode, further increasing the infiltration of the electrolyte into the electrode, reducing the effect of the electrode expansion on the electrolyte extrusion, and further improving the cycle life of the battery.

[0177] In some embodiments, the porosity of the first main region 411 of the insulating base layer 41 is 10% to 40%.

[0178] In some embodiments, the porosity of the edge region 412 of the insulating base layer is 0-20%.

[0179] The present application discloses in these embodiments a specific numerical range of the first main region 411 of the insulating base layer 41 and an edge region 412 of the insulating base layer. Within this numerical range, it is convenient for the electrolyte to infiltrate the electrode, reduces the effect of electrode expansion on electrolyte extrusion, and controls the effect of the porosity of the insulating base layer on the compression modulus.

[0180] In these embodiments, the present application discloses that the porosity of the first main region 411 of the above-mentioned insulating base layer 41 is any one of 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40% or any one of the values ​​satisfying any two of the above ranges.

[0181] In these embodiments, the present application discloses that the porosity of the edge area 412 of the above-mentioned insulating base layer is any one of 0, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20% or any one of the ranges of any two of the above.

[0182] In some embodiments, the insulating base layer includes a first edge region and a second edge region, the first edge region and the second edge region extend along a first direction and are arranged in a second direction, and the first main region is disposed between the first edge region and the second edge region; the first direction intersects with the second direction.

[0183] Specifically combined with the above Figure 6C It can be seen that the present application discloses in some embodiments that the insulating base layer 41 includes a first edge area 412a and a second edge area 412b, and a first main area 411 is provided between the first edge area 412a and the second edge area 412b, and the first edge area 412a, the second edge area 412b and the first main area 411 extend along the first direction and are arranged in the second direction. The present application discloses in these embodiments that the first direction is the x direction of the coordinate axis, which also refers to the length direction of the current collector, and the second direction is the y direction of the coordinate axis, which also refers to the width direction of the current collector. For a wound battery cell, the length direction of the current collector refers to the extension direction of the current collector, and the direction intersecting and perpendicular to the extension direction is the width direction of the current collector. For a laminated battery cell, the length direction and width direction of the current collector are determined according to the actual length value or width value or actual needs.

[0184] In some embodiments, the present invention selects Figure 6C The schematic structure distinguishes the edge area and the main area of ​​the insulating base layer 41, which is convenient for preparing the current collector and is also beneficial for controlling the performance of the current collector. The preparation process of the current collector is described in detail in the subsequent preparation method of the current collector.

[0185] The present application discloses in these embodiments Figure 6CIn the illustrated insulating base layer 41, the compression modulus of the above-mentioned first main region is 1.25GPa~2.50GPa; and / or; the porosity of the above-mentioned first main region is 10%~35%; and / or; the compression modulus of the above-mentioned first edge region and the second edge region are each independently selected from 2.0GPa~3.3Gpa; and / or; the compression modulus of the above-mentioned first edge region and the second edge region are each independently selected from 2.5%~20%.

[0186] The present application discloses in these embodiments Figure 6C The specific parameters of the compression modulus and porosity of each edge area and main area in the illustrated insulating base layer 41, within the parameter range, can not only alleviate the expansion of the electrode, but also facilitate the infiltration of the electrolyte into the electrode, which is conducive to better improving the cycle life of the battery.

[0187] In some embodiments, further combined Figure 6C , along the second direction, the first edge region 412a includes an A surface and a B surface that are oppositely disposed, and the distance between the A surface and the B surface is W1; along the second direction, the first main region 411 includes a C surface and a D surface that are oppositely disposed, and the distance between the C surface and the D surface is W2; along the second direction, the second edge region 412b includes an A' surface and a B' surface that are oppositely disposed, and the distance between the A' surface and the B' surface is W3; the present application is Figure 6C It is indicated that the B surface and the C surface are the same plane. Similarly, the D surface and the B' surface are the same plane. This application uses different symbols for illustration, and these symbols have no practical meaning. At the same time, the distance W2 between the C surface and the D surface, the distance W1 between the A surface and the B surface, and the distance W3 between the A' surface and the B' surface satisfy: W2: W1: W3 = 1~3: 1~2: 1~2.

[0188] In these embodiments, the present application controls the specific sizes of the edge regions and the main region on the insulating base layer 41, which not only facilitates the preparation of the current collector, but also helps to control the performance of the current collector.

[0189] In these embodiments, the present application discloses that W2:W1:W3 is any one of 1:1:1, 1:1:2, 1:2:1, 1:2:2, 2:1:1, 2:1:2, 2:2:1, 2:2:2, 3:1:1, 3:1:2, 3:2:1, 3:2:2 or any one of the ranges of any two of the above.

[0190] In some embodiments, the conductive layer includes a second main region, the second main region is provided with a through hole; the orthographic projection of the second main region on the insulating base layer at least partially overlaps with the first main region.

[0191] Combination Fig. 7A and Figure 7B It can be seen that the above-mentioned conductive layer 42 includes a second main area 421, and a through hole is provided on the second main area 421. As described above for the first main area 411 of the insulating base layer 41, the meaning of the second main area 421 of the conductive layer 42 remains the same as above. The advantages of the present application choosing to open a through hole in the second main area 421 of the conductive layer 42 include: the through hole can absorb part of the deformation stress caused by the expansion of the pole piece, and secondly, the electrolyte absorbed from the insulating base layer 41 flows from the through hole on the second main area 421 of the conductive layer 42 to the active material layer, which not only shortens the electrolyte transmission path, but also facilitates the infiltration of the electrolyte into the active material layer, and finally further improves the cycle life of the battery. The present application does not illustrate the through hole in the drawings. In fact, through holes of various shapes are within the protection scope of the present application.

[0192] Combination FIG. 5B to FIG. 5E It can be seen that the orthographic projection of the second main region 421 of the conductive layer 42 on the insulating base layer 41 at least partially overlaps with the first main region 411, wherein: Figure 5B , Figure 5C and Figure 5D The partial overlap is shown. Figure 5E The fully overlapped structure is shown, and the at least partially overlapped structure allows the electrolyte absorbed by the insulating base layer 41 to flow more conveniently from the through holes on the second main area 421 of the conductive layer 42 to the active material layer. The orthographic projection shape of the second main area 421 of the conductive layer 42 on the insulating base layer 41 includes any shape conventional in the art, such as a regular circle, oval, square, or various irregular shapes. The present application only shows some structures and shapes in 7A.

[0193] This application mainly uses the following specific embodiments Figure 5E The positional relationship between the conductive layer 42 and the insulating base layer 41 is discussed in a schematically completely overlapping design manner.

[0194] In some embodiments, the conductive layer 42 includes a second main region 421 and an edge region 422 of the conductive layer located outside the second main region 421; the second main region 421 of the conductive layer 42 is provided with a through hole, and the edge region 422 of the conductive layer is not provided with a hole. As described above, the main function of the conductive layer 42 is to collect the current generated by the active material of the battery so as to form a larger current for external output. In order to facilitate the flow of the electrolyte, the present application also chooses to open a through hole on the second main region 421 of the conductive layer 42. In order to reduce the influence of the through hole on the current transported by the conductive layer 42, the present application further chooses not to provide a hole in the edge region 422 of the conductive layer.

[0195] In some embodiments, the average pore diameter of the through holes is 100 nm to 10 μm.

[0196] The average pore size in the present application refers to the average value of the pore sizes of the through holes, which can be obtained by a scanning electron microscope.

[0197] In these embodiments, the present application discloses that the average pore diameter of the through holes is any one of 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1000nm, 2000nm, 3000nm, 4000nm, 5000nm, 6000nm, 7000nm, 8000nm, 9000nm, and 10000nm (10μm) or any one of the values ​​satisfying any two of the above ranges.

[0198] In some embodiments, in combination Figure 7B The conductive layer 42 includes a third edge region 422a and a fourth edge region 422b, the third edge region 422a and the fourth edge region 422b extend along the first direction and are arranged in the second direction, and the second main region 421 is disposed between the third edge region 422a and the fourth edge region 422b; the first direction intersects with the second direction. The first direction and the second direction described in these embodiments of the present application are the same as those described above, and are not described in detail in this application. The present application selects Figure 7B The schematic structure distinguishes the edge area and the main area of ​​the conductive layer 42, which is convenient for preparing the current collector and is also beneficial for controlling the performance of the current collector. The preparation process of the current collector is described in detail in the subsequent preparation method of the current collector.

[0199] In some embodiments, Figure 7B In the illustrated conductive layer 42 , the second main region 421 of the conductive layer 42 is provided with through holes, and the average aperture of the through holes is 200 nm to 6 μm, and the third edge region 422 a and the fourth edge region 422 b of the conductive layer 42 are not provided with holes.

[0200] In some embodiments, Figure 7B In the illustrated conductive layer 42, along the above-mentioned second direction, the above-mentioned third edge region 422a includes an E surface and an F surface arranged opposite to each other, and the distance between the E surface and the F surface is T1; along the above-mentioned second direction, the second main region 421 includes a G surface and an H surface arranged opposite to each other, and the distance between the G surface and the H surface is T2; along the above-mentioned second direction, the above-mentioned fourth edge region 422b includes an E' surface and an F' surface arranged opposite to each other, and the distance between the E' surface and the F' surface is T3; the distance T2 between the G surface and the H surface and the distance T1 between the E surface and the F surface and the distance T3 between the E' surface and the F' surface of the present application satisfy: T2:T1:T3=1~3:1~2:1~2.

[0201] In these embodiments, the present application controls the specific sizes of the edge regions and the main region on the conductive layer 42, which not only facilitates the preparation of the current collector, but also helps to control the performance of the current collector.

[0202] In these embodiments, the present application discloses that T2:T1:T3 is any one of 1:1:1, 1:1:2, 1:2:1, 1:2:2, 2:1:1, 2:1:2, 2:2:1, 2:2:2, 3:1:1, 3:1:2, 3:2:1, 3:2:2, or any one of the ranges satisfying any two of the above values.

[0203] In some embodiments, the formation method of the conductive layer 42 on the insulating base layer 41 in the present application includes any one or more of mechanical rolling, bonding, vapor deposition, chemical plating and electroplating methods.

[0204] In some embodiments, the material of the insulating base layer 41 includes any one or more of a polymer material and a polymer composite material. The polymer material includes any one or more of polyester terephthalate, polyethylene, polypropylene, epoxy resin, polyamide, polyimide, polyester, polyolefin, polyacetylene, siloxane polymer, polyether, polyol, polysulfone, polysaccharide polymer, amino acid polymer, polysulfur nitride polymer, and aromatic polymer. The polymer material also includes aromatic heterocyclic polymers, epoxy resins, phenolic resins, their derivatives, their cross-linked products, and their copolymers. A polymer composite material refers to two or more polymer materials.

[0205] In some embodiments, the polymer material includes one or more of polycaprolactam (commonly known as nylon 6), polyhexamethylene adipamide (commonly known as nylon 66), polyparaphenylene terephthalamide (PPTA), polymetaphenylene diamine (PMIA), and polyethylene terephthalate (PET). Or polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polycarbonate (PC), polyethylene (PE), polypropylene (PP), poly(propylene-ethylene) (PPE), polyvinyl alcohol (PVA), polystyrene (PS), polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTEE), polystyrene sulfonate (PSS), polyacetylene (PA), silicone rubber, polyoxymethylene (POM), polyphenylene ether (PPO), polyphenylene sulfide (PPS), polyethylene glycol (PEG), cellulose, starch, protein, polyphenylene, polypyrrole (PPy), polyaniline (PAN), polythiophene (PT), polypyridine (PPY), acrylonitrile-butadiene-styrene copolymer (ABS) and its derivatives, cross-linked products thereof, and copolymers thereof.

[0206] In some embodiments, the insulating base layer 41 may be a single layer or multiple layers. For a multiple layer insulating base layer 41 , the materials of each layer may be the same or different.

[0207] In some embodiments, the conductive layer 42 includes a metal, which includes any one or more of aluminum, aluminum alloy, copper, copper alloy, nickel, nickel alloy, iron, iron alloy, titanium, titanium alloy, silver and silver alloy.

[0208] The thickness of the insulating base layer and the thickness of the conductive layer of the present application remain the same as the conventional design method in the art.

[0209] In some embodiments, the insulating base layer 41 and the conductive layer 42 extend along a first direction and are stacked in a third direction; the first direction intersects the third direction; the first direction of the present application is the coordinate axis x direction, which also refers to the length direction of the current collector, and the third direction is the coordinate axis z direction, which also refers to the thickness direction of the film layer or the stacking direction of the film layer. Along the third direction, the thickness of the insulating base layer 41 is 25μm to 50μm; and / or; along the third direction, the thickness of the conductive layer 42 is 3μm to 10μm.

[0210] The present application selects an insulating base layer and a conductive layer with appropriate thickness, which not only exerts the intrinsic function of the current collector, but also facilitates the response to the adverse effects caused by the expansion of the pole piece.

[0211] The present application discloses in these embodiments that the thickness of the insulating base layer 41 is any one of 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, or any one of the values ​​within the range of any two of the above values.

[0212] In these embodiments, the present application discloses that the thickness of the conductive layer 42 is any one of 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, and 10 μm, or any one of the ranges of any two of the above values.

[0213] In some embodiments, the present application also discloses that a conductive carbon layer is formed on at least one side of the conductive layer 42, the conductive carbon layer includes conductive carbon, and the conductive carbon layer is formed on the surface of the conductive layer 42 by coating. The main area and the edge area of ​​the conductive carbon layer are arranged in the same manner as the conductive layer 42, and the opening position and manner are also the same as the conductive layer 42. The conductive carbon layer is conducive to improving the bonding ability between the conductive layer 42 and the active material layer, and further improving the interface stability, without affecting the electrolyte infiltration of the electrode.

[0214] The present application also discloses in some embodiments that a protective layer is provided between the conductive layer 42 and the insulating base layer 41, and the protective layer includes a metal oxide protective layer; the metal oxide protective layer has high mechanical strength, strong corrosion resistance, large specific surface area, and is conducive to increasing the bonding ability between the conductive layer 42 and the insulating base layer 41. The material of the metal oxide protective layer includes any one or more of aluminum oxide, cobalt oxide, nickel oxide, and chromium oxide. The formation method of the protective layer of the present application includes any one or more of vapor deposition, in-situ formation, and coating methods. At the same time, the main area and the edge area of ​​the protective layer are arranged in the same manner as the insulating base layer 41, and the opening position and method are also the same as the insulating base layer 41. The protective layer is conducive to improving the bonding ability between the conductive layer 42 and the insulating base layer 41 without affecting the infiltration of the electrolyte into the electrode, and further improving the interface stability.

[0215] In some embodiments, the present application discloses an electrode sheet formed by the above-mentioned current collector 4 and an active material layer.

[0216] In some embodiments, the electrode plate includes a positive electrode plate or a negative electrode plate, and the electrode plate includes a current collector 4 and an active material layer located on at least one side surface of the current collector 4 .

[0217] The positive electrode sheet 2, the separator 3 and the negative electrode sheet 1 of the present application can be wound or laminated to form a secondary battery. Figure 8 The secondary battery 10 is formed by a winding method, and the Figure 8 It can be seen that a negative electrode sheet 1 or a positive electrode sheet 2 is placed between two adjacent separators 3, and the negative electrode sheets 1 and the positive electrode sheets 2 are alternately arranged in sequence along the stacking direction (coordinate axis z direction). The number and size of the negative electrode sheets 1 and / or the positive electrode sheets 2 can be selected according to actual conditions, and this application will not be repeated. Figure 8 Only one winding method is illustrated, and other stacking or winding methods are within the scope of protection of this application. The formation method of the active material layer on the surface of the current collector 4 of this application includes any conventional method in the art, such as coating, deposition, etc. Coating includes any one or more of roller coating, extrusion coating, blade coating and gravure coating. Deposition includes any one or more of physical deposition and chemical deposition.

[0218] In some embodiments, the present application takes the negative electrode sheet as an example to specifically describe the positional relationship between the negative electrode active material layer and the current collector.

[0219] In some embodiments, in combination Fig.9AIt can be seen that the current collector 4 and the negative electrode active material layer 11 extend along a first direction and are stacked in a third direction; the first direction intersects the third direction; the first direction and the third direction here remain the same, and this application will not elaborate on them.

[0220] Along the third direction, the negative electrode active material layer 11 includes an M face and an N face that are arranged opposite to each other, the M face is arranged close to the current collector 4, and the distance between the M face and the N face is H; the area formed by extending from the M face to 0.1×H is recorded as the first area 11A, and the area formed by extending from the N face to 0.1×H is recorded as the second area 11B; the first area 11A includes the first negative electrode active material, and the second area 11B includes the second negative electrode active material; the median particle size of the first negative electrode active material is smaller than the median particle size of the second negative electrode active material. In this design, metal ions first react with the active material in the second area that is closest to them when passing through the separator. Since the particle size of the active material in the second area is large, the expansion of the negative electrode sheet due to lithium insertion is also small.

[0221] In some embodiments, Fig. 9B Schematically, the current collector 4 and the negative electrode active material layer 11 extend along a first direction and are stacked in a third direction; the first direction intersects with the third direction; along the third direction, the negative electrode active material layer 11 includes a first negative electrode active material layer 11a arranged close to the current collector 4, and a second negative electrode active material layer 11b located on the surface of the first negative electrode active material layer 11a away from the current collector 4; the first negative electrode active material layer 11a includes a first negative electrode active material, and the second negative electrode active material layer 11b includes a second negative electrode active material; the median particle size of the first negative electrode active material is smaller than the median particle size of the second negative electrode active material.

[0222] The present application describes the particle sizes of the negative electrode active material in the first region 11A close to the current collector 4 and the second region 11B away from the current collector 4 by taking the negative electrode active material layer 11 as an example. In fact, the positive electrode active material layer can also adopt the same or similar design as the negative electrode active material layer, which is not elaborated in the present application. In this design, the particle size of the active material particles in the first region close to the current collector is small, and the particle size of the active material particles in the second region away from the current collector is large. Compared with the pores formed between small particles, the pores between large particles are large, and the tortuosity of the path connecting the large pores is also small. Under the same compaction density, the electrolyte will preferentially infiltrate between the electrode layers along the path with larger pore size and smaller tortuosity during the infiltration process. Therefore, the design provided in the present application accelerates the infiltration of the electrolyte and the active material particles in the second region away from the current collector, and further accelerates the infiltration of the electrolyte into the active material in the first region, so the electrolyte fully and effectively infiltrates different intervals of the entire active material layer. Therefore, the design provided in the present application improves the uniformity of current distribution of the battery during charging and discharging to improve the cycle life of the battery.

[0223] In some embodiments, the positive electrode active material layer and the negative electrode active material layer are respectively located on both side surfaces of the current collector.

[0224] In some embodiments, the positive electrode active material layer and the negative electrode active material layer are simultaneously located on both sides of the current collector. Fig.10 It can be seen that the two oppositely disposed surfaces of the current collector 4 are respectively provided with a negative electrode active material layer 11 and a positive electrode active material layer 21. The design adopted in the present application is conducive to further improving the energy density of the battery.

[0225] Preparation method of current collector

[0226] Some embodiments of the present application disclose a method for preparing a current collector, comprising the following process:

[0227] Preparation of insulating base layer: extruding an organic polymer material through a twin-screw extruder to obtain a high-temperature melt, accurately metering the high-temperature melt through a melt pump and feeding it into a die head, passing the high-temperature melt flowing out of the slit of the die head through a chilled roller to obtain an extruded cast sheet, feeding the extruded cast sheet into a bidirectional asynchronous stretching machine to stretch it a certain multiple along the length direction, and then stretching the main area and the edge area separately along the width direction of the cast sheet, for example, the stretching multiple of the main area of ​​the organic polymer cast sheet in the width direction is a, and the stretching multiple of the edge area is b, then a is greater than b, so that the compression modulus of the main area of ​​the formed insulating base layer is smaller than the compression modulus of the edge area;

[0228] The prepared insulating base layer is placed in a high-temperature shaping device for a certain period of time to fully remove the membrane stress, so as to obtain a finished insulating base layer; and then it is cut to the required size according to the battery specification requirements.

[0229] Preparation of a conductive layer: After the insulating base layer prepared above is cleaned by acid washing, alkali washing, etc., it is placed in a vacuum evaporation chamber, a mask is placed in the main area of ​​the insulating base layer, and a conductive metal is deposited on at least one side of the surface of the insulating base layer at a high temperature of 1300°C to 2000°C. The main area of ​​the conductive layer prepared contains through holes, and the edge area does not contain through holes.

[0230] [Positive electrode]

[0231] According to some embodiments of the present application, as described above, the positive electrode plate comprises a current collector and a positive electrode film layer located on at least one side of the current collector, wherein the positive electrode film layer comprises a positive electrode active material.

[0232] According to some embodiments of the present application, when the positive electrode plate is applied to a lithium-ion battery, the positive electrode active material includes but is not limited to one or a combination of two or more of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and lithium phosphate containing an olivine structure; wherein the structural formula of the lithium phosphate containing an olivine structure is: LiFe 1-x-y Mn x M y PO4, 0≤x≤1, 0≤y<1, 0≤x+y≤1, M includes one or a combination of two or more transition metal elements or non-transition metal elements other than Fe and Mn, and M further includes any one or more of Cr, Mg, Ti, Al, Zn, W, Nb, and Zr.

[0233] The present application specifically includes but is not limited to LiCoO2, LiNiO2, LiMnO2, LiMn2O4, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2(NCM111), LiNi 0.5 Co 0.2 Mn 0.3 O2(NCM523), LiNi 0.6 CO 0.2 Mn 0.2 O2(NCM622), LiNi 0.8 CO 0.1 Mn 0.1 O2(NCM811), LiNi 0.85 CO 0.15 Al 0.05 Any one or more of O2, LiFePO4 (LFP) and LiMnPO4.

[0234] According to some embodiments of the present application, when the positive electrode plate is used in a sodium ion battery, the positive electrode active material includes but is not limited to at least one of a sodium transition metal oxide, a polyanionic compound, and a Prussian blue compound. Among them, in the sodium transition metal oxide, the transition metal can be any one or more of Mn, Fe, Ni, Co, Cr, Cu, Ti, Zn, V, Zr and Ce. The sodium transition metal oxide is, for example, Na x MO2, wherein M is one or more of Ti, V, Mn, Co, Ni, Fe, Cr and Cu, and 0<x≤1. Polyanionic compounds include sodium vanadium trifluorophosphate (Na3V2(PO4)2F3), sodium vanadium fluorophosphate (NaVPO4F), sodium vanadium phosphate (Na3V2(PO4)3), Na4Fe3(PO4)2P2O7, NaFePO4, and any one or more thereof. Prussian blue compounds are Na x M1M2(CN)6, wherein M1 and M2 are one or more of Fe, Mn, Co, Ni, Cu, Zn, Cr, Ti, V, Zr, and Ce, and 0<x≤2.

[0235] According to some embodiments of the present application, the positive electrode film layer also includes a conductive agent, a binder, etc. The conductive agent includes but is not limited to any one or more of graphite, superconducting carbon, carbon black (such as acetylene black, Ketjen black, Super P, etc.), carbon dots, carbon nanotubes, graphene and carbon nanofibers. The binder includes but is not limited to polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, fluorine-containing acrylate resin, styrene-butadiene rubber, polyacrylic acid, sodium polyacrylate, polyacrylamide, polyvinyl alcohol, sodium alginate, polymethacrylic acid, carboxymethyl chitosan, etc. The positive electrode current collector in the present application is as described above, and the present application is not repeated here.

[0236] The positive electrode current collector in the present application is as described above, and will not be elaborated here.

[0237] The method for forming the positive electrode film layer of the present application comprises mixing the above raw materials with a solvent (such as nitrogen methyl pyrrolidone) in a certain mass ratio to form a positive electrode slurry, and evenly coating the positive electrode slurry on both sides of the current collector; controlling a certain single-sided coating weight; and after drying, using a cold press to compact to a certain compaction density (2.4g / cm 3 ~3.4g / cm 3 ), that is, a positive electrode sheet including a positive electrode film layer is obtained.

[0238] [Negative electrode]

[0239] The negative electrode sheet of the present application includes a current collector and a negative electrode film layer located on one side surface or both sides surface of the current collector. Generally speaking, the negative electrode film layer is located on both sides surface of the current collector, and the formation method includes coating or deposition. The present application will take both sides as an example in the following.

[0240] The present application discloses in some embodiments that the negative electrode film layer includes a negative electrode active material, and the negative electrode active material includes one or more of a carbonaceous material, a silicon-based material, a silicon-carbon composite material, a tin-based material and its alloy material. The carbonaceous material in the present application includes one or more combinations of artificial graphite, natural graphite, soft carbon and hard carbon. Among them, artificial graphite, natural graphite, soft carbon, hard carbon, etc. include materials of any form conventional in the art, and include any conventional manufacturers and models in the art. The silicon-based material in the present application includes one or two of silicon-oxygen materials or silicon-carbon materials, or silicon-carbon composites. The tin-based and alloy materials in the present application include but are not limited to Li-Sn alloys, Li-Sn-O alloys, Sn, SnO, SnO2, etc. And the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for lithium-ion batteries or sodium-ion batteries can also be used. These negative electrode active materials can be used alone or in combination of two or more.

[0241] The present application discloses in some embodiments that the conductive agent comprises one or more of a point-shaped conductive agent, a linear conductive agent, and a planar conductive agent, wherein the point-shaped conductive agent comprises one or more of conductive carbon black (Super P or Super S), acetylene black, conductive graphite (KS-6 or KS-15 or SFG-6 or SFG-15), and Ketjen black, the linear conductive agent comprises one or more of single-walled carbon nanotubes, multi-walled carbon nanotubes, and carbon nanofibers, and the planar conductive agent comprises but is not limited to graphene.

[0242] The present application discloses in some embodiments that the negative electrode film layer includes a binder and a dispersant, etc. The binder includes but is not limited to polyvinyl alcohol, polyethylene glycol, sodium carboxymethyl cellulose, polyethylene oxide, polyacrylic acid, polyacrylamide, sodium alginate, styrene-butadiene rubber (SBR), etc. The dispersant also includes any conventional type in the art, such as cellulose and its salts, specifically including but not limited to methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, sodium carboxymethyl cellulose, lithium carboxymethyl cellulose, etc.

[0243] The negative electrode current collector in the present application is as described above, and will not be elaborated here.

[0244] The method for forming the negative electrode film layer of the present application comprises mixing the above raw materials with a solvent (such as deionized water) in a certain mass ratio to form a negative electrode slurry, defoaming the negative electrode slurry, and evenly coating the negative electrode slurry on both sides of the negative electrode current collector; controlling the single-side coating weight; drying, and using a cold press to compact to a certain compaction density (greater than or equal to 1.65g / cm 3 ), that is, a negative electrode sheet including a negative electrode film layer is obtained.

[0245] [Isolator]

[0246] Some embodiments of the present application disclose an isolating element. The present application has no particular limitation on the type of isolating element, and any known porous isolating element with good chemical stability and mechanical stability can be selected.

[0247] In some embodiments, the isolation member includes a base film layer and an organic coating layer, wherein the organic coating layer is located on at least one side surface of the base film layer.

[0248] In some embodiments, the present application discloses that an organic coating is disposed on both sides of the substrate film layer, the organic coating faces the positive electrode active material layer and the negative electrode active material layer of the battery cell, and the porosity of the organic coating is greater than the porosity of the substrate film layer. This design method is conducive to the effective infiltration of the active material layer into the electrolyte.

[0249] In some embodiments, the present application discloses that an organic coating is disposed on one side of the substrate film layer and an inorganic coating is disposed on the other side, wherein the organic coating faces the negative electrode active material layer of the battery cell and the inorganic coating faces the positive electrode active material layer. The organic coating of the present application is conducive to the full and effective infiltration of the negative electrode active material layer by the electrolyte, and the inorganic coating of the present application plays an insulating role, reducing the probability of piercing the separator and causing a short circuit.

[0250] As described above, the materials of the base film layer and the organic coating of the present application are independently selected from any one or more of polyethylene (PE), polypropylene (PP), poly(p-phenylene terephthalamide) (PPTA), polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), polyacrylonitrile (PAN), polyimide (PI) and polyamide (PA).

[0251] The inorganic coating of the present application includes a ceramic coating, and the ceramic particles in the ceramic coating include one or more of SiO2, Al2O3, AlOOH, CaO, TiO2, MgO, ZnO, ZrO2, Mg(OH)2 and BaSO4.

[0252] [Electrolytes]

[0253] In some embodiments of the present application, an electrolyte is disclosed. The electrolyte of the present application may be in a liquid state, a solid state, or a gel state. Among them, the solid state is a solid electrolyte, the liquid state is a liquid electrolyte, and the gel state is a gel electrolyte. The lithium-ion battery of the present application uses a liquid electrolyte, that is, an electrolyte. The electrolyte contains an electrolyte salt and an organic solvent. Among them, the types of electrolyte salts include any conventional types in the art, for example, including but not limited to inorganic metal salts, such as RClO4, RAsF6, RPF6, RBF4, RSbF6, RSO3F, RN(FSO2)2, etc.; fluorine-containing organic metal salts, such as RCF3SO3, RN(FSO2)(CF3SO2), RN(CF3SO2)2, RN(C2F5SO2)2, cyclic 1,3-hexafluoropropane disulfonyl imide lithium, cyclic 1,2-tetrafluoroethane disulfonyl imide lithium, RN(CF3SO2)(C4F9S O2), RC(CF3SO2)3, RPF4(CF3)2, RPF4(C2F5)2, RPF4(CF3SO2)2, RPF4(C2F5SO2)2, RBF2(CF3)2, RBF2(C2F5)2, RBF2(CF3SO2)2, RBF2(C2F5SO2)2, etc.; and metal salts containing dicarboxylic acid complexes, such as lithium bis(oxalato)borate, lithium difluorooxalatoborate, lithium tris(oxalato)phosphate, lithium difluorobis(oxalato)phosphate, lithium tetrafluoro(oxalato)phosphate, etc. The metal and R here contain lithium ions or sodium ions.

[0254] According to some embodiments of the present application, the concentration of the electrolyte salt in the electrolyte is 0.1mol / L to 4mol / L. The present application discloses in these embodiments that the concentration of the electrolyte salt is 0.1mol / L, 0.2mol / L, 0.3mol / L, 0.4mol / L, 0.5mol / L, 0.6mol / L, 0.7mol / L, 0.8mol / L, 0.9mol / L, 1mol / L, 1.2mol / L, 1.5mol / L, 1.8mol / L, 2mol / L, 2.2mol / L, 2.5mol / L, 2.8mol / L, 3mol / L, 3.2mol / L, 3.5mol / L, 3.8mol / L, 4mol / L, or any one of the values ​​satisfying the above range.

[0255] As described above, the organic solvent includes any one or more of carboxylic acid ester compounds, carbonate compounds, and ether compounds. Among them, the carboxylic acid ester compounds include one or more of ethyl acetate (EA), methyl acetate (MA), ethyl propionate (EP), propyl acetate (PA), methyl propionate (MP), methyl butyrate (MB), ethyl butyrate (EB), and 1,4-butyrolactone (GBL); the carbonate compounds include one or more of ethylene carbonate (EC), propylene carbonate (PC), vinylene carbonate, dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), ethyl methyl carbonate (EMC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene carbonate (BC), and fluoroethylene carbonate (FEC). The ether compounds include at least one of tetrahydrofuran, dimethyltetrahydrofuran, tetrahydropyran, dimethyltetrahydropyran, 1,2-dimethoxyethane, dipropylene glycol dimethyl ether, or dimethyl phthalate. The organic solvent of the present application further comprises one or two of nitrile solvents and sulfone solvents, wherein the nitrile solvent comprises one or more of acetonitrile (AN), glutaronitrile (GLN) and adiponitrile (ADN). The sulfone solvent comprises at least one or a combination of two of sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS) and diethyl sulfone (ESE).

[0256] According to some embodiments of the present application, the electrolyte further comprises a film-forming stabilizer, which comprises a positive electrode film-forming stabilizer and a negative electrode film-forming stabilizer, wherein the positive electrode film-forming stabilizer comprises carbonate additives and / or sulfate additives, and the carbonate additives include one or more of vinylene carbonate (VC), fluoroethylene carbonate (FEC), difluoroethylene carbonate (DFEC), vinyl ethylene carbonate (VEC) and dioctyl carbonate (CC). Sulfate additives include cyclic sulfonate additives and / or alkyl sulfate additives; further, cyclic sulfonate additives include one or more of 1,3-propane sultone (PS), propylene sultone (PES), and 3-fluoro-1,3-propane sultone (FPS); alkyl sulfate additives include one or more of vinyl sulfate (DTD), diethyl sulfate (DES) and dimethyl sulfate (DMS). The negative electrode film-forming stabilizer includes one or more of boron lithium salt or sodium salt, phosphorus-containing lithium salt or sodium salt, and sulfur-containing lithium salt or sodium salt; boron-containing lithium salt or sodium salt includes one or more of lithium or sodium tetrafluoroborate (LiBF4, NaBF4), lithium or sodium bisoxalate borate (LiBOB, NaBOB) and lithium or sodium bisfluorooxalate borate (LiDFOB, NaDFOB); phosphorus-containing lithium salt or sodium salt includes one or more of lithium or sodium difluorophosphate (LiPO2F2, NaPO2F2), lithium or sodium fluorophosphate (Li2PO3F, Na2PO3F) and lithium or sodium phosphate (Li3PO4, Na3PO4). Sulfur-containing lithium salt or sodium salt includes one or more of lithium or sodium fluorosulfonate (LiFSO3, NaFSO3), lithium or sodium sulfate (Li2SO4, Na2SO4), and lithium or sodium aminosulfonate (LiSO3NH2, NaSO3NH2).

[0257] In some embodiments, the above-mentioned electrolyte also includes an ionic liquid additive, the cation of which includes any one or more of nitrogen-containing onium ions and phosphonium-containing onium ions, and the anion of which includes any one or more of halogen ions, phosphate ions, borate ions, and sulfonyl imide anions.

[0258] In this application, the electrolyte is the carrier of ion transmission in the battery, and plays the role of conducting ions between the positive and negative electrodes of the battery. The type of electrolyte affects the safety of the battery. Ionic liquid additives refer to salts that are added to the electrolyte in a relatively small amount, are completely composed of cations and anions, and are liquid at room temperature or near room temperature, where room temperature refers to 25°C ± 5°C. Ionic liquid additives themselves have high thermal stability and low volatility. At the same time, the ionic liquid additives can also improve the stability of the negative electrode active material by forming a solid electrolyte interface film (SEI) and improving the stability of the film, thereby improving the safety of the battery.

[0259] In some embodiments, the cation of the ionic liquid additive comprises 1-butyl-3-methylimidazolium ([Bmin] + )、1-benzyl-3-methylimidazolium ([Bzmin] + ), 3-methyl-1-ethoxycarbonylmethylimidazolium ([Etmim] + )、1-alkyl-3-methylimidazolium ([Cnmim] + ), 1-[(trimethylsilyl)methyl]benzotriazolium ([SiMBIM] + )、N-alkyl-N-methylpiperidinium ([CnC1pip] + ), 5-azoniaspiro[4.4]nonane ([AS[mn]] + ), trihexyl(tetradecyl)phosphine ion ([Tf2N] + ), tetrabutylphosphine ion ([Pnnnn] + ), n-butyl-N-methylpyrrolidinium ([Pyr 14 ] + ) can be one or more of tetrabutylphosphine ion or n-butyl-N-methylpyrrolidinium.

[0260] In some embodiments, the anion of the ionic liquid additive comprises a chloride ion ([Cl] - ), bromide ion ([Br] - ), iodide ion ([I] - ), hexafluorophosphate ([PF6] - ), tetrafluoroborate ([BF4] - ), dicyandiamide anion ([N(CN)2] - ), bis(fluorosulfonyl)imide anion ([FSI] - ), bis(trifluoromethylsulfonyl)imide ([TFSI] - ) can be one or more of hexafluorophosphate or bis(fluorosulfonyl)imide anions.

[0261] In some embodiments, the ionic liquid additive includes one or more of tetrabutylphosphine hexafluorophosphate, tetrabutylphosphine bis(fluorosulfonyl)imide, n-butyl-N-methylpyrrolidine hexafluorophosphate, n-butyl-N-methylpyrrolidine bis(fluorosulfonyl)imide, 1-butyl-3-methylimidazolium bis(fluorosulfonyl)imide, 1-benzyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-benzyl-3-methylimidazolium bis(fluorosulfonyl)imide, and can be selected from tetrabutylphosphine hexafluorophosphate, tetrabutylphosphine bis(fluorosulfonyl)imide, n-butyl-N-methylpyrrolidine hexafluorophosphate, and n-butyl-N-methylpyrrolidine bis(fluorosulfonyl)imide.

[0262] The secondary battery of the present application will be described in detail below in conjunction with specific embodiments.

[0263] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0264] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0265] Conventional techniques of inorganic chemistry within the art can be used in this application. In the following examples, efforts are made to ensure the accuracy of the numbers used (including amounts, temperatures, reaction times, etc.), but some experimental errors and deviations should be considered. The temperatures (in degrees Celsius) used in the following examples are expressed in ° C, and the pressure is atmospheric pressure or near atmospheric pressure. All pharmaceutical reagents are purchased at AR grade, and all reactions are carried out under argon protection. Unless otherwise noted, all reagents are obtained from commercial channels.

[0266] Experimental materials:

[0267] The materials of the positive electrode active material, the negative electrode active material, the conductive layer and the insulating base layer are all commercially available.

[0268] Preparation Example 1

[0269] A method for preparing a current collector is provided, the method comprising the following steps:

[0270] S100, prepare insulating base layer: extrudes organic polymer material (polypropylene particles) through a twin-screw extruder at a temperature of 180°C to obtain a high-temperature melt, and feeds the high-temperature melt into a die after being accurately metered by a melt pump. The high-temperature melt flowing out of the slit of the die is passed through a chilled roller to obtain an extruded cast sheet, and the cast sheet is stretched 3 times along the length direction (coordinate axis x direction) using a bidirectional asynchronous stretching machine, and then the main area and the edge area are stretched separately along the width direction (coordinate axis y direction) of the organic polymer cast sheet, for example, the stretching multiple of the main area along the width direction of the cast sheet is 2 times, and the edge area is not stretched. After the stretching is completed, the insulating base layer is placed in a high-temperature shaping device at 130°C for 6 hours to fully remove the membrane stress, and the thickness of the insulating base layer is 8μm, wherein the structure of the insulating base layer is as follows Figure 6C , the ratio of the width W2 of the first main region to the width W1 of the first edge region and the width W3 of the second edge region is 3:1:1.

[0271] S200, preparing a conductive layer: cleaning the insulating base layer prepared above by acid washing, alkali washing, etc., placing it in a vacuum evaporation chamber, placing a mask plate in the main area of ​​the insulating base layer, the aperture of the mask plate is 1.2μm, depositing conductive metal copper on one side of the insulating base layer at a high temperature of 1300℃ to 2000℃ to form a copper conductive layer, and depositing conductive metal aluminum on the other side of the insulating base layer to form an aluminum conductive layer, the thickness of the copper conductive layer and the aluminum conductive layer are 10μm respectively, and the structures of the copper conductive layer and the aluminum conductive layer are as follows: Figure 7B The orthographic projection of the second main area of ​​the copper conductive layer and the aluminum conductive layer on the organic layer completely overlaps with the first main area of ​​the above-mentioned insulating base layer (the ratio of the width T2 of the second main area to the width T1 of the third edge area and the width T3 of the fourth edge area is 3:1:1), and the second main area of ​​the copper conductive layer and the aluminum conductive layer is provided with through holes, and no holes are provided in the edge area.

[0272] Comparative Example Preparation Example 1

[0273] A method for preparing a current collector is provided. The method for preparing a current collector is provided. The method for preparing a current collector is different from the above-mentioned Preparation Example 1 in that in step S100, the main area and the edge area of ​​the insulating base layer are not stretched in the width direction, and there are no through holes on the conductive layer.

[0274] Comparative Example Preparation Example 2

[0275] A method for preparing a current collector is provided. The method for preparing a current collector is provided. The method for preparing a current collector is different from the above-mentioned Preparation Example 1 in that in step S100, for example, the main area along the width direction of the casting sheet is not stretched, and the edge area is stretched 2 times.

[0276] Preparation Example 2-1

[0277] A method for preparing a current collector is provided. The method is different from the above-mentioned Preparation Example 1 in that in step S100, the stretching ratio of the main area of ​​the casting along the width direction is 3.5 times, and the stretching ratio of the edge area is 1.5 times, and the rest remains the same as Preparation Example 1.

[0278] Preparation Example 2-2

[0279] A method for preparing a current collector is provided. The method is different from the above-mentioned Preparation Example 1 in that in step S100, the stretching ratio of the main area of ​​the casting along the width direction is 5 times, and the stretching ratio of the edge area is 1 times, and the rest remains the same as Preparation Example 1.

[0280] Preparation Example 2-3

[0281] A method for preparing a current collector is provided. The method is different from the above-mentioned Preparation Example 1 in that in step S100, the stretching ratio of the main area of ​​the casting along the width direction is 3.5 times, and the stretching ratio of the edge area is 2.2 times, and the rest remains the same as Preparation Example 1.

[0282] Preparation Example 3-1

[0283] A method for preparing a current collector is provided. The method is different from the above-mentioned Preparation Example 1 in that in step S200, no mask is set, that is, there is no through hole on the formed conductive layer, and the rest remains the same as Preparation Example 1.

[0284] Preparation Example 4-1

[0285] A method for preparing a current collector is provided. The method is different from the above-mentioned Preparation Example 1 in that in step S200, the average pore size of the through holes on the conductive layer is 4.8 μm, and the rest remains the same as Preparation Example 1.

[0286] The pore size parameters and liquid absorption capacity of the current collectors prepared in the above preparation examples and comparative examples are tested as follows:

[0287] (1) Test the compression modulus of the insulation base layer:

[0288] The battery cell was placed in a 1.0 mol / L sodium hydroxide aqueous solution at room temperature for discharge treatment. After the discharge was completed, the pole pieces and separators were manually disassembled. The current collector of the pole piece was finely sliced ​​layer by layer at different thickness positions (the smallest scale could reach nanoscale thin slices) by using a cryo-focused ion beam (FIB) to separate the insulating base layer and the conductive layer. Different area regions of the insulating base layer were then cut to obtain main area samples and edge area samples.

[0289] Tested in accordance with the national standard GB / T 1041-2008 / ISO 604:2002 for testing the compression properties of plastics:

[0290] (1) Specimen preparation: Specimen type and size: According to the standard requirements, the size and shape of the specimen must comply with the regulations: specimen length 50±2mm, width 10±0.2mm, thickness 4±0.2mm (obtain the corresponding thickness by stacking multiple layers).

[0291] (2) Sample processing: The sample should be prepared by mechanical processing to avoid mechanical damage such as delamination, scratches and local extrusion. After processing, it should be dried under appropriate conditions.

[0292] (3) Testing equipment: universal material testing machine.

[0293] (4) Specimen size measurement: Use a vernier caliper to measure the width and thickness of the specimen along its length.

[0294] (5) Specimen installation: Install the specimen in the compression fixture of the universal material testing machine to ensure that the specimen does not slip or twist during the compression process.

[0295] (6) Setting test parameters: Set the compression speed of the testing machine to a constant 1 mm / min.

[0296] (7) Start the test: Start the testing machine to perform compression and record the force-displacement data during the test until the specified compression ratio is reached or the specimen is destroyed.

[0297] (8) Data recording: record the maximum force value, corresponding displacement and other data during the compression process.

[0298] (9) Calculation of compression modulus: Compression modulus refers to the ratio of compression stress to compression strain within the linear range of the stress-strain curve. The unit is MPa. Calculation method: By drawing the compression load-strain curve, selecting the load and deformation data of at least 5 points in the linear region, and calculating the ratio of stress to strain, the compression modulus is obtained.

[0299] (2) Test the porosity of the insulating base layer:

[0300] The dried film samples were cut into square specimens of about 20 mm × 20 mm. The thickness and actual side length were measured by a digital micrometer and a vernier caliper. The volume V was calculated and the weight M0 was weighed. The square specimens were then immersed in n-hexadecane reagent and taken out after soaking for 2 h at room temperature and air atmosphere. The n-hexadecane reagent liquid adsorbed on the surface was removed and then the weight M was weighed. t , then the porosity of each membrane layer satisfies the following mathematical relationship:

[0301] Porosity = (M t -M0) / ρ×V×100%;

[0302] The ρ in the above mathematical relationship is the density of the n-hexadecane reagent, in g / mm 3 , V is the volume of the square sample of each film layer, in mm 3 , weight M0 and M t The unit is g, and the weight measuring instrument is a thousandth balance.

[0303] (3) Test the saturated liquid absorption rate of the current collector to the electrolyte:

[0304] First, weigh the mass of the composite current collector and record it as m0. Then, completely immerse the weighed composite current collector in the electrolyte for 2 hours, then take it out and wipe off the residual electrolyte on the surface with dust-free paper, and weigh it again and record it as m1. The maximum liquid absorption rate of the composite current collector is calculated using the following formula:

[0305] θ=(m1-m0) / m0×100%;

[0306] In the above formula, θ is the liquid absorption rate, %.

[0307] The above electrolyte is the electrolyte of Example 1.

[0308] (4) Test the average pore size of the through holes in the conductive layer:

[0309] A sample of the edge region of the conductive layer was obtained.

[0310] The test instrument used is ASAP2460-physical adsorption analyzer. The samples after drying and degassing are placed in liquid nitrogen. Different test pressures are adjusted to measure the adsorption amount of nitrogen respectively, and the adsorption and desorption isotherms are drawn. Then, the pore volume and specific surface area of ​​each sample are obtained according to the adsorption and desorption isotherms, and then the average pore size is calculated.

[0311] Table 1 Parameters and performance list of current collector

[0312]

[0313] Combining the preparation example 1 and the comparative preparation examples 1 and 2 in Table 1, it can be seen that the pore size and porosity of the insulating base layer affect the saturated liquid absorption capacity of the current collector for the electrolyte.

[0314] Combining Preparation Example 1 and Comparative Preparation Example 1, Example 3-1 and Example 4-1 in Table 1, it can be seen that the through holes and the pore size in the edge area of ​​the conductive layer have little effect on the saturated liquid absorption rate of the current collector.

[0315] Example 1

[0316] A method for preparing a battery cell is provided, wherein the structure diagram of the pole piece of the battery cell is as follows Fig.10 Indicate, combine Fig.10It can be seen that the negative electrode active material layer 11 is provided on one surface of the current collector 4 , and the positive electrode active material layer 21 is provided on the other surface.

[0317] The preparation method of the battery cell includes the following preparation process:

[0318] Preparation of positive electrode sheet:

[0319] Take the ternary material LiNi 0.5 Co 0.3 Mn 0.2 O2 (NCM532), conductive carbon black, and PVDF were mixed in a ratio of 93:2:5, and nitrogen methyl pyrrolidone solvent was added and stirred to form a positive electrode slurry. The positive electrode slurry was coated on the surface of the aluminum metal layer of the positive electrode current collector prepared in the above preparation example 1, and heated and dried. Specifically, a multi-section oven was used, and the temperature settings were 120℃ / 100℃ / 90℃, and then a cold press was used for compaction to obtain a positive electrode film layer with a compaction density of 2.8g / cm 3 .

[0320] Preparation of negative electrode sheet:

[0321] Artificial graphite (median particle size Dv50 is 21.7 μm) and conductive agent conductive carbon black, stabilizer carboxymethyl cellulose and binder SBR are dispersed in deionized water in a mass ratio of 96.5:1.0:1.0:1.5 to form a negative electrode slurry. The negative electrode slurry is evenly coated on the surface of the copper conductive layer obtained in the above Preparation Example 1, and dried in a nine-section oven with the temperature settings of 100°C / 100°C / 95°C / 85°C / 85°C / 80°C / 80°C / 80°C / 60°C, and then compacted using a cold press. The compaction density of the negative electrode film layer is 1.65 g / cm 3 .

[0322] Isolators available:

[0323] A porous polypropylene (PP) film with a thickness of 10 μm was used as the separator.

[0324] Provide electrolyte:

[0325] In an argon atmosphere glove box with a water content of <10ppm, EC (ethylene carbonate), PC (polycarbonate), and DMC (dimethyl carbonate) are mixed in a weight ratio of EC:PC:DMC=3:3:3, and then LiPF6, VC, DTD and PS are added and stirred evenly to obtain an electrolyte, wherein the concentration of LiPF6 in the lithium-ion battery electrolyte is 1 mol / L, and the mass percentages of VC, DTD, and PS are 3%, 1%, and 1%, respectively, to obtain an electrolyte.

[0326] Assembling battery cells:

[0327] The positive electrode sheet, separator and negative electrode sheet are stacked in order, so that the separator is placed between the positive electrode sheet and the negative electrode sheet to play an isolating role, and the corresponding assembly forms a wound bare battery cell; the wound bare battery cell is placed in an outer packaging shell, and after drying, the electrolyte is injected, and after vacuum packaging, standing, forming, shaping and other processes, a battery cell is obtained.

[0328] Comparative Example 1

[0329] A method for preparing a battery monomer is provided. The difference between Comparative Example 1 and Example 1 is that the current collector is replaced with the current collector of Comparative Preparation Example 1, and the other parts are the same as Example 1.

[0330] Comparative Example 2

[0331] A method for preparing a battery monomer is provided. The difference between Comparative Example 1 and Example 1 is that the current collector is replaced with the current collector of Comparative Preparation Example 2, and the rest is the same as Example 1.

[0332] Example 2-1

[0333] A method for preparing a battery monomer is provided. The difference between Example 2-1 and Example 1 is that the current collector is replaced with the current collector of Preparation Example 2-1, and the rest is the same as Example 1.

[0334] Example 2-2

[0335] A method for preparing a battery monomer is provided. The difference between Example 2-2 and Example 1 is that the current collector is replaced with the current collector of Preparation Example 2-2, and the rest is the same as Example 1.

[0336] Example 2-3

[0337] A method for preparing a battery cell is provided. The difference between Example 2-3 and Example 1 is that the current collector is replaced with the current collector of Preparation Example 2-3, and the rest is the same as Example 1.

[0338] Example 3-1

[0339] A method for preparing a battery cell is provided. The difference between Example 3-1 and Example 1 is that the current collector is replaced with the current collector of Preparation Example 3-1, and the rest is the same as Example 1.

[0340] Example 4-1

[0341] A method for preparing a battery monomer is provided. The difference between Example 4-1 and Example 1 is that the current collector is replaced with the current collector of Preparation Example 4-1, and the rest remains the same as Example 1.

[0342] Example 5-1

[0343] A method for preparing a battery cell is provided. The difference between Example 5-1 and Example 1 is that the negative electrode film layer is Fig. 9B Schematic, wherein the particle size Dv50 of the first graphite in the first negative electrode film layer arranged close to the current collector is 6.5μm, the particle size Dv50 of the second graphite in the second negative electrode film layer arranged away from the current collector is 21.7μm, and the difference between the first graphite and the second graphite is only the particle size, and the others remain the same. The thickness of the first negative electrode film layer is consistent with the thickness of the second negative electrode film layer, and the others remain the same as in Example 1.

[0344] The batteries prepared in the above-mentioned embodiments and comparative examples of the present application were cycled for 500 cycles at 25°C to calculate the capacity retention rate, and the batteries were disassembled to further observe the lithium deposition on the negative electrode surface. The specific test methods and results are as follows:

[0345] (5) Test the capacity retention rate of the battery after 500 cycles at 25°C:

[0346] Under a constant temperature environment of 25℃, the battery was charged to 4.4V at a constant current of 1C, then charged at a constant voltage of 4.4V until the current dropped to 0.05C, and then discharged to 2.5V at a constant current of 1C to obtain the first cycle discharge capacity (Cd1); this charging and discharging was repeated until the 500th cycle, and the discharge capacity after 500 cycles was recorded as Cdn.

[0347] Capacity retention rate (%) = discharge capacity after 500 cycles (Cdn) / first cycle discharge capacity (Cd1)

[0348] (6) Determination and analysis of lithium deposition on the surface of the negative electrode after the battery has been cycled 500 times at 25°C:

[0349] After the battery was cycled 500 times according to the above-mentioned cycle method, it was charged to 4.3V at a constant current of 0.33C, and then charged at a constant voltage of 4.3V until the current dropped to 0.05C. The battery was then disassembled, and the positive and negative electrodes were further separated. A scanning electron microscope was used to observe the lithium deposition on the surface of the negative electrode, especially the surface lithium deposition in the main area of ​​the negative electrode.

[0350] The judgment criteria are as shown in the following table;

[0351] Table 2 Determination level of lithium deposition on the surface of negative electrode

[0352]

[0353] The performance test results of the batteries prepared in the above embodiments and comparative examples are shown in Table 3 below.

[0354] Table 3 Battery performance list

[0355]

[0356]

[0357] From Example 1, Comparative Example 1 and Comparative Example 2 in Table 3, it can be seen that the present application adopts the above-mentioned design method to make the volume change degree of the first main area of ​​the insulating base layer greater than the volume change degree of the edge area, which has a buffering effect on the expansion of the electrode to a certain extent, thereby improving the cycle life of the battery by alleviating the expansion of the electrode.

[0358] Combining Example 1, Example 2-1 and Example 2-3 in Table 3, it can be seen that the main area and edge area of ​​the insulating base layer have appropriate porosity and a certain appropriate width, which is beneficial to improving the cycle life of the battery.

[0359] Combining Example 1 and Example 5-1 in Table 3, it can be seen that the present application adopts a matching design method for the current collector and the active material layer, which is beneficial to further improve the cycle life of the battery.

[0360] In summary, the design method provided in the present application improves the cycle life of the battery by alleviating the expansion of the electrode during the charging and discharging process of the battery.

[0361] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; 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 all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell, characterized in that: It includes a current collector and an active material layer located on at least one side of the current collector; The current collector includes an insulating base layer, the insulating base layer includes a first main region and an edge region located outside the first main region; the compression modulus of the first main region of the insulating base layer is smaller than the compression modulus of the edge region of the insulating base layer; The current collector further includes a conductive layer, and the conductive layer is located between the insulating base layer and the active material layer.

2. The battery cell according to claim 1, characterized in that: The compression modulus of the first main region of the insulating base layer is Q1, and the compression modulus of the edge region of the insulating base layer is Q2; Satisfies: Q2 / Q1=1.20~2.

25.

3. The battery cell according to any one of claims 1 to 2, characterized in that: The compression modulus of the first main region of the insulating base layer is Q1, and Q1 is 0.8 GPa to 2.8 GPa; and / or; The compression modulus of the edge area of ​​the insulating base layer is Q2, and Q2 is 1.8 GPa to 3.4 GPa.

4. The battery cell according to any one of claims 1 to 3, characterized in that: The porosity of the first main region of the insulating base layer is greater than the porosity of the edge region of the insulating base layer.

5. The battery cell according to any one of claims 1 to 4, characterized in that: The porosity of the first main region of the insulating base layer is 10% to 40%; and / or; The porosity of the edge area of ​​the insulating base layer is 0-20%.

6. The battery cell according to any one of claims 1 to 5, characterized in that: The insulating base layer comprises a first edge region and a second edge region, the first edge region and the second edge region extend along a first direction and are arranged in a second direction, and the first main region is disposed between the first edge region and the second edge region; The first direction intersects the second direction; The compression modulus of the first main body region is 1.25 GPa to 2.50 GPa; and / or; The porosity of the first main body region is 10% to 35%; and / or; The compression modulus of the first edge region and the second edge region are independently selected from 2.0 GPa to 3.3 GPa; and / or; The porosity of the first edge region and the second edge region are each independently selected from 2.5% to 20%.

7. The battery cell according to claim 6, characterized in that: Along the second direction, the first edge region includes an A surface and a B surface that are oppositely arranged, and a distance between the A surface and the B surface is W1; Along the second direction, the first main body region includes a C surface and a D surface that are oppositely arranged, and the distance between the C surface and the D surface is W2; Along the second direction, the second edge region includes an A' surface and a B' surface that are oppositely arranged, and a distance between the A' surface and the B' surface is W3; Satisfies: W2:W1:W3=1~3:1~2:1~2.

8. The battery cell according to any one of claims 1 to 7, characterized in that: The conductive layer includes a second main body region, and the second main body region is provided with a through hole; An orthographic projection of the second body region on the insulating base layer at least partially overlaps with the first body region.

9. The battery cell according to claim 8, characterized in that: The conductive layer includes a second main body region and an edge region located outside the second main body region; The second main region of the conductive layer is provided with a through hole, and the edge region of the conductive layer is not provided with a hole.

10. The battery cell according to any one of claims 8 to 9, characterized in that: The average pore diameter of the through holes is 100 nm to 10 μm.

11. The battery cell according to any one of claims 8 to 10, characterized in that: The conductive layer includes a third edge region and a fourth edge region, the third edge region and the fourth edge region extend along the first direction and are arranged in the second direction, and the second main region is disposed between the third edge region and the fourth edge region; The first direction intersects the second direction; The second main body region of the conductive layer is provided with through holes, and the average pore diameter of the through holes is 200nm to 6μm; The third edge region and the fourth edge region of the conductive layer are not provided with holes.

12. The battery cell according to claim 11, characterized in that: Along the second direction, the third edge region includes an E surface and an F surface that are arranged opposite to each other, and a distance between the E surface and the F surface is T1; Along the second direction, the second main body region includes a G surface and an H surface that are arranged opposite to each other, and a distance between the G surface and the H surface is T2; Along the second direction, the fourth edge region includes an E' surface and an F' surface that are oppositely arranged, and a distance between the E' surface and the F' surface is T3; Satisfies: T2:T1:T3=1~3:1~2:1~2.

13. The battery cell according to any one of claims 1 to 12, characterized in that: The material of the insulating base layer includes any one or more of polyester terephthalate, polyethylene, polypropylene, epoxy resin, polyamide, polyimide, polyester, polyolefin, polyacetylene, siloxane polymer, polyether, polyol, polysulfone, polysaccharide polymer, amino acid polymer, polysulfur nitride polymer, and aromatic ring polymer; and / or; The conductive layer includes a metal, and the metal includes any one or more of aluminum, aluminum alloy, copper, copper alloy, nickel, nickel alloy, iron, iron alloy, titanium, titanium alloy, silver and silver alloy.

14. The battery cell according to any one of claims 1 to 13, characterized in that: The insulating base layer and the conductive layer extend along a first direction and are stacked in a third direction; The first direction intersects the third direction; Along the third direction, the thickness of the insulating base layer is 25 μm to 50 μm; and / or; Along the third direction, the thickness of the conductive layer is 3 μm to 10 μm.

15. The battery cell according to any one of claims 1 to 14, characterized in that: The current collector and the active material layer extend along a first direction and are stacked in a third direction; The first direction intersects the third direction; Along the third direction, the active material layer includes an M surface and an N surface that are arranged opposite to each other, the M surface is arranged close to the current collector, and the distance between the M surface and the N surface is H; The area extending from the M surface to 0.1×H is recorded as the first area, and the area extending from the N surface to 0.1×T1 is recorded as the second area; The first region includes a first active material, and the second region includes a second active material; The median particle size of the first active material is smaller than the median particle size of the second active material.

16. The battery cell according to any one of claims 1 to 15, characterized in that: The current collector and the active material layer extend along a first direction and are stacked in a third direction; The first direction intersects the third direction; Along the third direction, the active material layer includes a first active material layer disposed close to the current collector and a second active material layer disposed on a surface of the first active material layer away from the current collector; The first active material layer includes a first active material, and the second active material layer includes a second active material; The median particle size of the first active material is smaller than the median particle size of the second active material.

17. A current collector, characterized in that: Including insulating base; The insulating base layer comprises a first main body region and an edge region located outside the first main body region; the compression modulus of the first main body region of the insulating base layer is smaller than the compression modulus of the edge region of the insulating base layer; The current collector further includes a conductive layer, and the conductive layer is located between the insulating base layer and the active material layer.

18. A battery device, characterized in that: The invention comprises the battery cell according to any one of claims 1 to 16 or the current collector according to claim 17.

19. An electrical device, characterized in that: A battery device comprising the battery device of claim 18.

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