Preparation method of diaphragm, battery monomer, battery device and electric equipment

Abstract

The invention relates to the technical field of battery production, in particular to a preparation method of a diaphragm, a battery monomer, a battery device and electric equipment. The preparation method of the diaphragm comprises the following steps: acquiring operation parameter distribution of a coating area when a battery monomer is in a test state; dividing into a plurality of coating areas according to the running parameter distribution; providing a base film; according to the multiple coating areas, the base membrane is coated with the coating to obtain the diaphragm, the multiple coating areas are arranged side by side in the width direction of the diaphragm, and the ionic conductivity of the diaphragm in each coating area is increased from the middle to the two sides in the width direction of the diaphragm, so that when the single battery is subjected to low-rate charging and high-power discharging, the ionic conductivity of the diaphragm in each coating area is increased; the ion conduction rates in the battery monomers approach to the same, so that the operating parameters of the coating areas of the battery monomers approach to the same, and the cycle performance and the service life of the battery monomers are improved.

Description

Technical Field

[0001] The present application relates to the technical field of battery production, and in particular to a method for preparing a diaphragm, a battery cell, a battery device and an electrical equipment. Background Art

[0002] This section merely provides background information related to the present disclosure and is not necessarily prior art.

[0003] As new energy technologies become increasingly mature, new energy vehicles and other electrical equipment are gradually entering the public eye. The core technology of new energy vehicles lies in the battery device, and the safety and stability of the battery device directly determine the performance of the entire vehicle.

[0004] The battery device includes a battery cell, and the battery cell includes an electrode assembly. The middle part of the electrode assembly along the height direction is prone to the highest temperature due to the inability to effectively dissipate heat. This will cause the middle part of the electrode assembly to become the area with the fastest reaction rate and the highest capacity decay, resulting in inconsistent capacity decay at different positions of the electrode assembly, and the capacity of the electrode assembly is prone to decay too quickly. Summary of the invention

[0005] In view of the above problems, the present application provides a method for preparing a diaphragm, a battery cell, a battery device and an electrical equipment, which solve the problem of excessive capacity decay of the electrode assembly caused by inconsistent capacity decay at different positions of the electrode assembly in the prior art.

[0006] A first aspect of an embodiment of the present application provides a method for preparing a diaphragm, the diaphragm is applied to a battery cell, a coating area is provided on the diaphragm, and the method for preparing the diaphragm includes:

[0007] Obtaining the distribution of operating parameters of the coating area of ​​the battery cell when it is in a test state;

[0008] Divided into multiple coating areas according to the distribution of operating parameters;

[0009] providing a basement membrane;

[0010] The coating is applied to the base film according to a plurality of coating regions to obtain a separator, wherein the plurality of coating regions are arranged side by side along a width direction of the separator, and the ion conductivity of the separator in each coating region increases from the middle to both sides.

[0011] The embodiment of the present application obtains the operating parameter distribution of the coating area of ​​the battery cell in the test state, divides it into multiple coating areas according to the operating parameter distribution, and applies the coating to the base film according to the multiple coating areas to obtain a diaphragm, wherein the multiple coating areas are arranged side by side along the width direction of the diaphragm, and the ionic conductivity of the diaphragm in each coating area increases from the middle to both sides along the width direction of the diaphragm. This allows the ion conduction rate inside the battery cell to approach the same when the battery cell is charged at a low rate and discharged at a high power, so that the operating parameters of the coating area of ​​the battery cell are close to each other, thereby improving the cycle performance and service life of the battery cell.

[0012] The method for preparing the diaphragm according to the embodiment of the present application also includes the following technical features:

[0013] In some embodiments of the present application, dividing into multiple coating areas according to the distribution of operating parameters includes dividing the coating area into multiple coating areas according to the temperature distribution, and dividing the coating area into multiple coating areas according to the temperature range, wherein the middle area along the width direction of the diaphragm is the area with the highest average temperature, and the middle area is the area with the lowest ion conductivity.

[0014] The embodiments of the present application divide the coating area into multiple coating areas according to the temperature distribution, and divide the multiple coating areas according to the temperature interval, wherein the middle area is the area with the highest average temperature, and the middle area is the area with the lowest ion conductivity. The coating area can be partitioned along the width direction of the diaphragm according to the temperature distribution, thereby dividing the coating area into multiple coating areas including the area with the highest average temperature, wherein the ion conductivity of the area with the highest average temperature is the lowest, which can reduce the reaction rate of the area with the highest average temperature, thereby making the reaction rates of multiple coating areas tend to be consistent, thereby reducing the capacity decay of the battery cells.

[0015] In some embodiments of the present application, dividing into multiple coating areas according to the distribution of operating parameters also includes determining the area with the highest average temperature as the first coating area; extending from the area with the highest average temperature to both sides along the width direction of the diaphragm, the area with a temperature at a first threshold is the second coating area, and the average temperature of the first threshold is lower than the average temperature of the area with the highest average temperature, and the ionic conductivity of the second coating area is greater than or equal to the ionic conductivity of the first coating area.

[0016] In the embodiment of the present application, the area with the highest average temperature is determined as the first coating area; the area extending from the area with the highest average temperature to both sides along the width direction of the diaphragm, where the temperature is at the first threshold is the second coating area, and the average temperature of the first threshold is lower than the average temperature of the area with the highest average temperature, and the ion conductivity of the second coating area is greater than or equal to the ion conductivity of the first coating area. Then, the coating area can be partitioned along the width direction of the diaphragm according to the temperature distribution, thereby dividing the coating area into a plurality of coating areas including the first coating area and the second coating area, wherein the ion conductivity of the area with the highest average temperature is the smallest, which can reduce the reaction rate of the area with the highest average temperature, thereby making the reaction rates of the plurality of coating areas including the first coating area and the second coating area tend to be consistent, thereby reducing the capacity decay of the battery cell.

[0017] In some embodiments of the present application, the coating area is divided according to the temperature range and extends from the middle area of ​​the coating area to both sides along the width direction of the diaphragm. It also includes extending from the second coating area to the direction away from the area with the highest average temperature along the width direction of the diaphragm. The area where the temperature is at the second threshold is the third coating area, and the average temperature of the second threshold is lower than the average temperature of the first threshold, and the ionic conductivity of the third coating area is greater than or equal to the ionic conductivity of the second coating area.

[0018] In the embodiment of the present application, by setting a region extending from the second coating region in a direction away from the region with the highest average temperature along the width direction of the diaphragm, the region with a temperature at the second threshold is the third coating region, and the average temperature of the second threshold is lower than the average temperature of the first threshold, and the ion conductivity of the third coating region is greater than or equal to the ion conductivity of the second coating region, the coating area can be divided into a plurality of coating regions including the first coating region, the second coating region and the third coating region, wherein the ion conductivity of the first coating region is the smallest, the ion conductivity of the second coating region is larger, and the ion conductivity of the third coating region is the largest, thereby reducing the reaction rates of the first coating region and the second coating region, so that the reaction rates of the plurality of coating regions including the first coating region, the second coating region and the third coating region tend to be consistent, thereby reducing the capacity decay of the battery cell.

[0019] In some embodiments of the present application, dividing into multiple coating areas according to the distribution of operating parameters includes dividing into multiple coating areas according to the capacity retention rate, and dividing into multiple coating areas according to the interval in which the capacity retention rate is located, wherein the middle area along the width direction of the diaphragm is the area with the lowest capacity retention rate, and the middle area is the area with the lowest ion conductivity.

[0020] The embodiments of the present application are divided into multiple coating areas according to the capacity retention rate, and the multiple coating areas are divided according to the interval of the capacity retention rate, wherein the middle area is the area with the lowest capacity retention rate, and the middle area is the area with the lowest ion conductivity. The coating area can be partitioned along the width direction of the diaphragm according to the distribution of the capacity retention rate, so that the coating area is divided into multiple coating areas including the area with the lowest capacity retention rate, wherein the ion conductivity of the area with the lowest capacity retention rate is the smallest, which can reduce the reaction rate in the area with the highest average temperature, so that the reaction rates of multiple coating areas tend to be consistent, thereby reducing the capacity attenuation of the battery cell.

[0021] In some embodiments of the present application, dividing into multiple coating areas according to the distribution of operating parameters also includes determining the area with the lowest capacity retention rate as the first coating area; extending from the area with the lowest capacity retention rate to both sides along the width direction of the diaphragm, the area with the capacity retention rate within the first area range is the second coating area, and the average capacity retention rate of the first area range is greater than the average capacity retention rate of the area with the lowest capacity retention rate, and the ionic conductivity of the second coating area is greater than or equal to the ionic conductivity of the first coating area.

[0022] In the embodiment of the present application, the area with the lowest capacity retention rate is determined as the first coating area; extending from the area with the lowest capacity retention rate to both sides along the width direction of the diaphragm, the area with the capacity retention rate within the first area range is the second coating area, and the average capacity retention rate within the first area range is lower than the average capacity retention rate of the area with the highest average temperature, and the ion conductivity of the second coating area is greater than or equal to the ion conductivity of the first coating area. Then, the coating area can be partitioned along the width direction of the diaphragm according to the distribution of the capacity retention rate, thereby dividing the coating area into a plurality of coating areas including the first coating area and the second coating area, wherein the ion conductivity of the area with the highest average temperature is the smallest, which can reduce the reaction rate of the area with the highest capacity retention rate, thereby making the reaction rates of the plurality of coating areas including the first coating area and the second coating area tend to be consistent, thereby reducing the capacity attenuation of the battery cell.

[0023] In some embodiments of the present application, the coating regions divided into multiple regions according to the distribution of operating parameters also include extending along the width direction of the diaphragm from the second coating region in a direction away from the region with the lowest capacity retention rate, and the region with a capacity retention rate within the second region range is the third coating region, and the capacity retention rate within the second region range is lower than the capacity retention rate within the first region range, and the ionic conductivity of the third coating region is greater than or equal to the ionic conductivity of the second coating region.

[0024] The embodiments of the present application are arranged to extend from the second coating area in a direction away from the area with the lowest capacity retention rate along the width direction of the diaphragm, and the area with the capacity retention rate within the second area is the third coating area, and the capacity retention rate within the second area is lower than the capacity retention rate within the first area, and the ion conductivity of the third coating area is greater than or equal to the ion conductivity of the second coating area. Then, the coating area can be divided into a plurality of coating areas including the first coating area, the second coating area and the third coating area, wherein the ion conductivity of the area with the lowest capacity retention rate is the smallest, the ion conductivity of the second coating area is larger, and the ion conductivity of the third coating area is the largest, thereby reducing the reaction rates of the first coating area and the second coating area, so that the reaction rates of the plurality of coating areas including the first coating area, the second coating area and the third coating area tend to be consistent, thereby reducing the capacity attenuation of the battery cell.

[0025] In some embodiments of the present application, the base film is a porous structure.

[0026] In the embodiments of the present application, the base membrane is formed into a porous structure, so that when the battery cell is working, ions can pass through the porous structure to achieve the discharge and charge process.

[0027] In some embodiments of the present application, coating multiple coating areas on the base film to obtain the diaphragm specifically includes coating the base film with a coating device, wherein the coating device has multiple coating ports, and the multiple coating ports are arranged side by side along the width direction of the diaphragm.

[0028] In an embodiment of the present application, a coating device is used to coat the base film, wherein the coating device has multiple coating ports, and the multiple coating ports are arranged side by side along the width direction of the diaphragm. Each coating area can be coated separately through the multiple coating ports, thereby facilitating the control of the ionic conductivity of each coating area.

[0029] In some embodiments of the present application, the raw material of the coating includes at least one of zirconium oxide ceramics, polycarbonate, aluminum oxide, boehmite, polymethyl methacrylate, aramid fiber and polyvinylidene fluoride.

[0030] In the embodiments of the present application, the raw materials of the coating include at least one of zirconium oxide ceramics, polycarbonate, alumina, boehmite, polymethyl methacrylate, aramid fiber and polyvinylidene fluoride, and the coating formula can be designed by at least one of these raw materials to control the ionic conductivity of each coating area.

[0031] In some embodiments of the present application, the ionic conductivity of the separator in each coating region increases from the middle to both sides by controlling at least one of the formula of the raw materials, the coating weight and the compaction density of the coating layer in each coating region.

[0032] The embodiments of the present application control the ionic conductivity of each coating area by controlling at least one of the formula of the raw materials, the coating weight and the compaction density of the coating of each coating area, thereby achieving differentiated settings of the ionic conductivity of different coating areas.

[0033] In some embodiments of the present application, coating multiple coating areas on the base film to obtain the diaphragm includes coating multiple coating areas on the base film with different thicknesses, and compacting the coatings to obtain the diaphragm.

[0034] In the embodiment of the present application, coatings of different thicknesses are applied to multiple coating areas on a base membrane, and the coatings are compacted to obtain a diaphragm. Differentiated settings of ionic conductivity can be achieved by applying coatings of different compaction densities or different coating weights to multiple coating areas.

[0035] A second aspect of the embodiments of the present application provides a battery cell, wherein the battery cell includes a diaphragm manufactured by the diaphragm preparation method mentioned in the above embodiments.

[0036] A third aspect of the embodiments of the present application provides a battery device, including a battery box and a battery cell as mentioned in the above embodiments, wherein the battery cell is disposed in the battery box.

[0037] A fourth aspect of the embodiments of the present application provides an electrical device, which includes the battery device mentioned in the above implementation, and the battery device is used to store or provide electrical energy.

[0038] 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

[0039] 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:

[0040] Figure 1 A schematic diagram of the structure of an electrical device provided in some embodiments of the present application;

[0041] Figure 2 A schematic diagram of the structure of a battery device provided in some embodiments of the present application;

[0042] Figure 3A schematic diagram of the structure of a battery cell provided in some embodiments of the present application;

[0043] Figure 4 A schematic diagram of the structure of an electrode assembly provided in some embodiments of the present application;

[0044] Figure 5 A schematic diagram of the structure of a diaphragm provided in some embodiments of the present application;

[0045] Figure 6 A schematic diagram of the structure of a coating device provided in some embodiments of the present application;

[0046] Figure 7 for Figure 5 The diaphragm shown in FIG. 1 is a schematic structural diagram of a second viewing angle (in a state before compaction);

[0047] Figure 8 for Figure 5 The diaphragm shown in FIG. 1 is a schematic structural diagram of a second viewing angle (in a compacted state);

[0048] Fig. 9 A flow chart of a method for preparing a diaphragm provided in some embodiments of the present application.

[0049] The reference numerals are as follows:

[0050] 100, battery device; 200, electrical equipment; 300, controller; 400, motor;

[0051] 10. Battery cell; 11. Electrode assembly; 111. Positive electrode sheet; 112. Negative electrode sheet; 113. Diaphragm; 1131. Coating area; 11311. First coating area; 11312. Second coating area; 11313. Third coating area; 11314. Fourth coating area; 11315. Fifth coating area; 114. Tab; 12. Shell; 121. Shell body; 122. End cover;

[0052] 20. Battery box; 21. First box; 22. Second box; 23. Accommodation space;

[0053] 500, coating device; 501, first coating system; 5011, first coating channel; 5012, first coating port; 5013, first slurry layer; 502, second coating system; 5021, second coating channel; 5022, second coating port; 5023, second slurry layer; 503, third coating system; 5031, third coating channel; 5032, third coating port; 5033, third slurry layer; 504, fourth coating system; 5041, fourth coating channel; 5042, fourth coating port; 5043, fourth slurry layer; 505, fifth coating system; 5051, fifth coating channel; 5052, fifth coating port; 5053, fifth slurry layer;

[0054] 600, basement membrane;

[0055] XX, width direction;

[0056] YY, length direction. DETAILED DESCRIPTION

[0057] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0058] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0059] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0060] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0061] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0062] In the description of the embodiments of the present 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 pieces" refers to more than two pieces (including two pieces).

[0063] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial" and "circumferential" etc. indicate orientations or positional relationships 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 a limitation on the embodiments of the present application.

[0064] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected" and "fixed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0065] At present, from the perspective of market development, the application of battery devices is becoming more and more extensive. Battery devices are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars, as well as military equipment and aerospace and other fields. With the continuous expansion of the application field of battery devices, the market demand is also constantly expanding.

[0066] The battery device involved in the embodiment of the present application can be used in, but not limited to, electrical equipment such as vehicles, ships or aircraft. The battery device comprising the battery cells, battery devices, etc. involved in the present application can be used.

[0067] In the embodiments of the present application, the electrical equipment using the battery device as the power source may be, but is not limited to, mobile phones, tablets, laptop computers, electric toys, electric tools, battery cars, electric cars, ships, spacecraft, etc. Among them, the electric toys may include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and the spacecraft may include airplanes, rockets, space shuttles, and spacecraft, etc.

[0068] It should be understood that the technical solutions described in the embodiments of the present application are not limited to the battery devices and electrical equipment described above, but can also be applied to all batteries including a box and electrical equipment using the battery.

[0069] The battery cell includes an electrode assembly and an electrolyte. The electrode assembly is composed of a positive electrode sheet, a negative electrode sheet and a separator. The battery cell mainly relies on the movement of metal ions between the positive electrode sheet and the negative electrode sheet to work. The positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer. The positive electrode active material layer is coated on the surface of the positive electrode current collector. The current collector not coated with the positive electrode active material layer protrudes from the current collector coated with the positive electrode active material layer. The current collector not coated with the positive electrode active material layer is stacked as a positive electrode tab. Taking lithium-ion batteries as an example, the material of the positive electrode current collector can be aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganese oxide. The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer. The negative electrode active material layer is coated on the surface of the negative electrode current collector. The current collector not coated with the negative electrode active material layer protrudes from the current collector coated with the negative electrode active material layer. The current collector not coated with the negative electrode active material layer is stacked as a negative electrode tab. The material of the negative electrode current collector can be copper, and the negative electrode active material can be carbon or silicon. The material of the isolation film may be PP (polypropylene) or PE (polyethylene), etc. In addition, the electrode assembly may be a winding structure or a stacked structure, but the embodiments of the present application are not limited thereto.

[0070] The technical solutions described in the embodiments of the present application are applicable to various electrical devices that use battery cells, such as mobile phones, portable devices, laptop computers, electric vehicles, electric toys, electric tools, vehicles, ships and spacecraft, for example, spacecraft include airplanes, rockets, space shuttles and spacecraft, etc.

[0071] The battery device includes a battery cell, and the battery cell includes an electrode assembly. The middle part of the electrode assembly along the height direction is prone to the highest temperature due to the inability to effectively dissipate heat. This will cause the middle part of the electrode assembly to become the area with the fastest reaction rate and the highest capacity decay, resulting in inconsistent capacity decay at different positions of the electrode assembly, and the capacity of the electrode assembly is prone to decay too quickly.

[0072] In order to solve this problem, an embodiment of the present application proposes a method for preparing a diaphragm, wherein the diaphragm is applied to a battery cell, and a coating area is provided on the diaphragm. The method for preparing the diaphragm includes obtaining the operating parameter distribution of the coating area of ​​the battery cell when the battery cell is in a test state; dividing the coating area into multiple coating areas according to the operating parameter distribution; providing a base film; and coating the multiple coating areas on the base film to obtain a diaphragm, wherein the multiple coating areas are arranged side by side along the width direction of the diaphragm, and the ionic conductivity of the diaphragm in each coating area increases from the middle to both sides. The diaphragm prepared by this method can make the ion conduction rate inside the battery cell approach the same when the battery cell is charged at a low rate and discharged at a high power, so that the operating parameters of the coating area of ​​the battery cell are close to each other, thereby improving the cycle performance and service life of the battery cell.

[0073] The method for preparing the diaphragm in the embodiment of the present application can be used in the production process of battery monomers to prepare the diaphragm of the battery monomers.

[0074] The structure in the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0075] For the convenience of description, the following embodiments are described by taking the electric device as a vehicle as an example.

[0076] Combined with Figure 1 As shown, the vehicle 200 can be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery device 100 is arranged inside the vehicle 200, and the battery device 100 can be arranged at the bottom, head or tail of the vehicle 200. The battery device 100 can be used to power the vehicle 200, for example, the battery device 100 can be used as an operating power source for the vehicle 200. The vehicle 200 may also include a controller 300 and a motor 400, and the controller 300 is used to control the battery device 100 to power the motor 400, for example, for the starting, navigation and driving power requirements of the vehicle 200.

[0077] In some embodiments of the present application, the battery device 100 can not only serve as an operating power source for the vehicle 200, but also serve as a driving power source for the vehicle 200, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 200.

[0078] Combined with Figure 2 As shown, the embodiment of the present application provides a battery device 100, which can be a secondary battery or a primary battery, or a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 10 and the battery device 100 can be cylindrical, flat, rectangular, or in other shapes.

[0079] The battery device 100 (Battery Apparatus) mentioned in the embodiment of the present application may include one or more battery cell assemblies for providing voltage and capacity. The battery cell assembly (Battery Cell Assembly) may include a plurality of battery cells 10, and the plurality of battery cells 10 are connected in series, in parallel or in mixed connection through a busbar component.

[0080] In some embodiments, a battery cell assembly is generally formed by arranging a plurality of battery cells 10; as an example, the battery cell assembly may be a battery module, which is formed by arranging and fixing a plurality of battery cells 10 to form an independent module. As an example, a battery module may be formed by bundling a plurality of battery cells 10 by a cable tie.

[0081] In some embodiments, the battery device 100 may be a battery pack, which includes a battery case 20 and one or more battery cell assemblies, wherein the battery cell assemblies are housed in the battery case 20 .

[0082] As an example, the battery cell assembly may be a battery module, and the battery cell assembly may be accommodated in the battery case 20 by fixing the battery module in the battery case 20 .

[0083] As an example, the battery cell assembly may also be accommodated in the battery case 20 by directly fixing the plurality of battery cells 10 to the battery case 20 .

[0084] The battery case 20 is used to provide a storage space 23 for the battery cell 10, and the battery case 20 can adopt a variety of structures. In some embodiments, the battery case 20 may include a first case 21 and a second case 22, the first case 21 and the second case 22 cover each other, and the first case 21 and the second case 22 jointly define a storage space 23 for accommodating the battery cell 10.

[0085] As an example, the battery box 20 can be a part of the chassis structure of the vehicle 200. For example, the battery box 20 can become at least a part of the floor of the vehicle 200, or the frame of the battery box 20 can become at least a part of the cross beam and longitudinal beam of the vehicle 200.

[0086] Combined with Figure 4 and Figure 5 As shown, an embodiment of the present application further provides a battery cell 10 , which includes an electrode assembly 11 and a separator 113 . The electrode assembly 11 includes a negative electrode sheet 112 and a positive electrode sheet 111 . Both the positive electrode sheet 111 and the negative electrode sheet 112 are provided with a tab 114 .

[0087] In some embodiments, the battery cell 10 also includes a shell 12 and an adapter (not shown in the figure), the shell 12 includes a shell body 121 and an end cover 122, the shell body 121 is an open structure at the upper end, the electrode assembly 11 is installed in 12, the end cover 122 is covered on the shell body 121, and is connected to the pole ear 114 of the electrode assembly 11 through the adapter.

[0088] like Fig. 9 As shown, the embodiment of the present application further proposes a method for preparing a diaphragm 113. The diaphragm 113 is applied to a battery cell 10. A coating area 1131 is provided on the diaphragm 113. The method for preparing the diaphragm 113 includes:

[0089] S91, obtaining the operating parameter distribution of the coating area 1131 of the battery cell 10 in the test state;

[0090] S92, dividing into a plurality of coating areas according to the distribution of operating parameters;

[0091] S93, providing a base film 600;

[0092] S94, according to the plurality of coating regions, coating the coating on the base film 600 to obtain the diaphragm 113, wherein the plurality of coating regions are arranged side by side along the width direction of the diaphragm 113, the ionic conductivity of the diaphragm 113 in each coating region increases from the middle to both sides, and the width direction of the diaphragm 113 is Figure 5 The XX direction in the diaphragm 113 is the length direction of Figure 5 The YY direction in .

[0093] When the battery cell 10 is in a test state, it is usually charged at a low rate and discharged at a high power, which may easily cause the electrode assembly of the battery cell 10 to decay too quickly. Therefore, the embodiments of the present application need to reduce the capacity decay of the battery cell 10.

[0094] In S91, the operating parameter distribution of the coating area 1131 of the battery cell 10 in the test state is obtained, wherein the operating parameter distribution includes the distribution temperature and the capacity retention rate distribution, wherein the capacity retention rate refers to the proportion of the charge capacity retained by the battery cell 10 during use to the initial charge capacity. Specifically, the capacity retention rate is a percentage value calculated by comparing the battery capacity at a certain moment with the initial capacity. For example, if the initial capacity is 100%, after a period of use, the capacity of the battery may become 90%, then the capacity retention rate at this time is 90%.

[0095] The temperature distribution of the coating area 1131 of the battery cell 10 in the test state can be measured by setting a plurality of temperature sensors in the coating area 1131. In order not to affect the normal operation of the battery cell 10, the temperature sensors can also be set at different positions on the surface of the electrode assembly 11, and the number of temperature sensors is multiple, so as to detect the temperature of different positions of the electrode assembly 11. The test state mentioned here can be a fully discharged state, that is, the process of fully discharging the battery cell 10 after it is fully charged.

[0096] In S92, the coating area is divided into a plurality of coating areas according to the distribution of the operating parameters, wherein the average temperature of each coating area is different and the average capacity retention rate of each coating area is also different.

[0097] Considering that the capacity retention rates at different positions of each coating area are different, the average capacity retention rate of each coating area is used here to characterize the capacity retention rate of the coating area, and the average value of the capacity retention rate of the coating area can be used to represent the average capacity retention rate of the coating area.

[0098] In S93, the base film 600 can be provided by melting, extruding, and blowing a polyolefin resin into a crystalline polymer film, and then undergoing a crystallization treatment and annealing to obtain a highly oriented multilayer structure. The film is further stretched at a high temperature to peel off the crystal surface to form a porous structure, thereby increasing the pore size of the crystalline polymer film to obtain a base film 600 with a porous structure.

[0099] In S94, according to multiple coating areas, the coating is applied to the base film 600 to obtain the diaphragm 113. The coating can be applied by the coating device 500. During the coating of the base film 600, one side of the base film 600 can be coated, or both sides of the base film 600 can be coated.

[0100] The embodiment of the present application obtains the operating parameter distribution of the coating area 1131 of the battery cell 10 in the test state, divides it into multiple coating areas according to the operating parameter distribution, and applies the coating to the base film 600 according to the multiple coating areas to obtain the diaphragm 113, wherein the multiple coating areas are arranged side by side along the width direction of the diaphragm 113, and the ionic conductivity of the diaphragm 113 in each coating area increases from the middle to both sides. Therefore, when the battery cell 10 is charged at a low rate and discharged at a high power, the ionic conduction rate inside the battery cell 10 approaches the same, so that the operating parameters of the coating area 1131 of the battery cell 10 are close to each other, thereby improving the cycle performance and service life of the battery cell 10.

[0101] Optionally, dividing into multiple coating areas according to the distribution of operating parameters includes dividing the coating area 1131 into multiple coating areas according to the temperature distribution, and dividing into multiple coating areas according to the temperature interval, wherein the middle area along the width direction of the diaphragm 113 is the area with the highest average temperature, and the middle area is the area with the lowest ion conductivity.

[0102] It should be noted that the temperature in the area with the highest average temperature is a range value. For example, the temperature range corresponding to the area with the highest average temperature is 50°C to 62°C. At this time, since the middle area is also the area with the fastest reaction rate, it is necessary to control the ionic conductivity of the middle area so that the ionic conductivity of the middle area is the lowest.

[0103] The embodiment of the present application divides the coating area 1131 into multiple coating areas according to the temperature distribution, and divides the multiple coating areas according to the temperature interval, wherein the middle area is the area with the highest average temperature, and the middle area is the area with the lowest ion conductivity. The coating area 1131 can be partitioned along the width direction of the diaphragm 113 according to the temperature distribution, so that the coating area 1131 is divided into multiple coating areas including the area with the highest average temperature, wherein the ion conductivity of the area with the highest average temperature is the lowest, which can reduce the reaction rate of the area with the highest average temperature, thereby making the reaction rates of multiple coating areas tend to be consistent, thereby reducing the capacity decay of the battery cell 10.

[0104] Alternatively, if Figure 5 As shown, the coating is divided into multiple coating areas according to the distribution of operating parameters, and the area with the highest average temperature is also determined as the first coating area 11311; extending from the area with the highest average temperature to both sides along the width direction of the diaphragm 113, the area with a temperature at the first threshold is the second coating area 11312, and the average temperature of the first threshold is lower than the average temperature of the area with the highest average temperature, and the ion conductivity of the second coating area 11312 is greater than or equal to the ion conductivity of the first coating area 11311.

[0105] It should be noted that the second coating area 11312 is located outside the first coating area 11311, the average temperature within the first threshold is lower than the average temperature of the area with the highest average temperature, and the ionic conductivity of the second coating area 11312 is greater than or equal to the ionic conductivity of the first coating area 11311. The temperature within the first threshold here is also a range value, such as the temperature within the first threshold is 47°C to 55°C. Of course, the temperature span of the first threshold and the temperature span of the area with the highest average temperature can be the same, such as the temperature of the area with the highest average temperature is 50°C to 62°C, the temperature span is 12°C, and the temperature span within the first threshold is also 12°C.

[0106] In the embodiment of the present application, the area with the highest average temperature is determined as the first coating area 11311; the area extending from the area with the highest average temperature to both sides along the width direction of the diaphragm 113, where the temperature is at the first threshold, is the second coating area 11312, and the average temperature of the first threshold is lower than the average temperature of the area with the highest average temperature, and the ion conductivity of the second coating area 11312 is greater than or equal to the ion conductivity of the first coating area 11311. Then, the coating area 1131 can be partitioned along the width direction of the diaphragm 113 according to the temperature distribution, so that the coating area 1131 is divided into a plurality of coating areas including the first coating area 11311 and the second coating area 11312, wherein the ion conductivity of the area with the highest average temperature is the smallest, which can reduce the reaction rate of the area with the highest average temperature, so that the reaction rates of the plurality of coating areas including the first coating area 11311 and the second coating area 11312 tend to be consistent, thereby reducing the capacity decay of the battery cell 10.

[0107] Optionally, extending from the middle area of ​​the coating area 1131 to both sides along the width direction of the diaphragm, dividing the coating area according to the temperature range also includes extending from the second coating area 11312 along the width direction of the diaphragm 113 in the direction away from the area with the highest average temperature, the area where the temperature is at the second threshold is the third coating area 11313, and the average temperature of the second threshold is lower than the average temperature of the first threshold, and the ionic conductivity of the third coating area 11313 is greater than or equal to the ionic conductivity of the second coating area 11312.

[0108] It should be noted that the third coating area 11313 is located outside the second coating area 11312, the average temperature within the second threshold is lower than the average temperature of the area with the highest average temperature, the average temperature within the second threshold is also lower than the average temperature of the first threshold, and the ion conductivity of the second coating area 11312 is greater than or equal to the ion conductivity of the first coating area 11311. The temperature within the second threshold here is also a range value, such as the temperature within the second threshold is 45°C to 51°C. Of course, the temperature span of the first threshold and the temperature span of the area with the highest average temperature can be the same, such as the temperature of the area with the highest average temperature is 50°C to 62°C, the temperature span is 12°C, and the temperature span within the second threshold is also 12°C.

[0109] In the embodiment of the present application, by setting the width direction of the diaphragm 113, extending from the second coating area 11312 to the direction away from the area with the highest average temperature, the area with the temperature at the second threshold is the third coating area 11313, and the average temperature of the second threshold is lower than the average temperature of the first threshold, and the ion conductivity of the third coating area 11313 is greater than or equal to the ion conductivity of the second coating area 11312, then the coating area 1131 can be divided into the first coating area 11311, the second coating area 11312 and the third coating area There are multiple coating areas in the domain 11313, among which the ion conductivity of the first coating area 11311 is the smallest, the ion conductivity of the second coating area 11312 is larger, and the ion conductivity of the third coating area 11313 is the largest, thereby reducing the reaction rates of the first coating area 11311 and the second coating area 11312, so that the reaction rates of the multiple coating areas having the first coating area 11311, the second coating area 11312 and the third coating area 11313 tend to be consistent, thereby reducing the capacity attenuation of the battery cell 10.

[0110] It should be noted that the ionic conductivity of each coating area may also adopt the same parameter. In this case, the ionic conductivity of the diaphragm 113 in each coating area is the same.

[0111] In some embodiments of the present application, dividing the coating area 1131 into multiple coating areas according to the distribution of operating parameters includes dividing the coating area 1131 into multiple coating areas according to the capacity retention rate, and dividing the coating area into multiple coating areas according to the interval of the capacity retention rate, wherein the middle area is the area with the lowest capacity retention rate, and the middle area is the area with the lowest ion conductivity.

[0112] We mentioned earlier that the operating parameter distribution includes temperature distribution and capacity retention rate distribution. The previous section is about the division of multiple coating areas based on temperature distribution. In the embodiments of the present application, the partitions can also be set according to the capacity retention rate. The following focuses on the technical solution of partitioning according to the capacity retention rate.

[0113] The middle region is the region with the highest average temperature and also the region with the lowest capacity retention rate. Therefore, the reaction rate in the middle region needs to be reduced. Therefore, the middle region is the region with the lowest ion conductivity.

[0114] The embodiment of the present application divides the coating area 1131 into multiple coating areas according to the capacity retention rate, and divides the multiple coating areas according to the interval of the capacity retention rate, wherein the middle area is the area with the lowest capacity retention rate, and the middle area is the area with the lowest ion conductivity. The coating area 1131 can be partitioned along the width direction of the diaphragm 113 according to the distribution of the capacity retention rate, so that the coating area 1131 is divided into multiple coating areas including the area with the lowest capacity retention rate, wherein the ion conductivity of the area with the lowest capacity retention rate is the smallest, which can reduce the reaction rate of the area with the highest average temperature, thereby making the reaction rates of multiple coating areas tend to be consistent, thereby reducing the capacity attenuation of the battery cell 10.

[0115] Optionally, dividing into multiple coating areas according to the distribution of operating parameters also includes determining that the area with the lowest capacity retention rate is the first coating area 11311; extending from the area with the lowest capacity retention rate to both sides along the width direction of the diaphragm 113, the area with the capacity retention rate within the first area range is the second coating area 11312, and the average capacity retention rate of the first area range is greater than the average capacity retention rate of the area with the lowest capacity retention rate, and the ion conductivity of the second coating area 11312 is greater than or equal to the ion conductivity of the first coating area 11311.

[0116] Considering that the temperatures of the first coating area 11311 and the second coating area 11312 are different and the temperature of the first coating area 11311 is higher, the ion conductivity of the second coating area 11312 needs to be greater than or equal to the ion conductivity of the first coating area 11311.

[0117] In the embodiment of the present application, the area with the lowest capacity retention rate is determined as the first coating area 11311; extending from the area with the lowest capacity retention rate to both sides along the width direction of the diaphragm 113, the area with the capacity retention rate within the first area range is the second coating area 11312, and the average temperature of the first area range is lower than the average temperature of the area with the highest average temperature, and the ion conductivity of the second coating area 11312 is greater than or equal to the ion conductivity of the first coating area 11311, then the coating area 1131 can be partitioned along the width direction of the diaphragm 113 according to the distribution of the capacity retention rate, thereby dividing the coating area 1131 into a plurality of coating areas including the first coating area 11311 and the second coating area 11312, wherein the ion conductivity of the area with the lowest capacity retention rate is the smallest, which can reduce the reaction rate of the area with the lowest capacity retention rate, thereby making the reaction rates of the plurality of coating areas including the first coating area 11311 and the second coating area 11312 tend to be consistent, thereby reducing the capacity decay of the battery cell 10.

[0118] In some embodiments of the present application, the coating regions divided into multiple regions according to the distribution of operating parameters also include extending along the width direction of the diaphragm 113, from the second coating region 11312 in the direction away from the region with the lowest capacity retention rate, and the region with the capacity retention rate within the second region range is the third coating region 11313, and the capacity retention rate within the second region range is lower than the capacity retention rate within the first region range, and the ionic conductivity of the third coating region 11313 is greater than or equal to the ionic conductivity of the second coating region 11312.

[0119] Considering that the temperatures of the first coating area 11311, the second coating area 11312 and the third coating area 11313 are different, and the temperature of the first coating area 11311 is higher, it is necessary to make the ionic conductivity of the second coating area 11312 greater than or equal to the ionic conductivity of the first coating area 11311, and the ionic conductivity of the third coating area 11313 greater than or equal to the ionic conductivity of the second coating area 11312.

[0120] In the embodiment of the present application, the coating area 1131 is divided into the first coating area 11311 and the second coating area 11312 by setting the width direction of the separator 113, extending from the second coating area 11312 to the direction away from the area with the lowest capacity retention rate, and the area with the capacity retention rate in the second area range is the third coating area 11313, and the capacity retention rate in the second area range is lower than the capacity retention rate in the first area range, and the ion conductivity of the third coating area 11313 is greater than or equal to the ion conductivity of the second coating area 11312. 2 and the third coating area 11313, among which the ion conductivity of the area with the lowest capacity retention rate is the smallest, the ion conductivity of the second coating area 11312 is relatively large, and the ion conductivity of the third coating area 11313 is the largest, thereby reducing the reaction rates of the first coating area 11311 and the second coating area 11312, so that the reaction rates of the multiple coating areas having the first coating area 11311, the second coating area 11312 and the third coating area 11313 tend to be consistent, thereby reducing the capacity attenuation of the battery cell 10.

[0121] It should be emphasized that the boundaries of the first coating area 11311, the second coating area 11312 and the third coating area 11313 determined according to the temperature distribution and the boundaries of the first coating area 11311, the second coating area 11312 and the third coating area 11313 determined according to the capacity retention rate distribution can be the same or different.

[0122] Optionally, the base film 600 is a porous structure.

[0123] The porous structure here means that the base film 600 has a plurality of pores.

[0124] In the embodiment of the present application, the base film 600 is formed into a porous structure, so that when the battery cell 10 is working, ions can pass through the porous structure to achieve the discharge and charge process.

[0125] Alternatively, if Figure 6 As shown, coating multiple coating areas on the base film 600 to obtain the diaphragm 113 specifically includes using a coating device 500 to coat the base film 600, wherein the coating device 500 has multiple coating ports, and the multiple coating ports are arranged side by side along the width direction of the diaphragm 113.

[0126] In the embodiment of the present application, a coating device 500 is used to coat the base film 600, wherein the coating device 500 has a plurality of coating ports, and the plurality of coating ports are arranged side by side along the width direction of the diaphragm 113. Each coating area can be coated separately through the plurality of coating ports, thereby facilitating the control of the ionic conductivity of each coating area.

[0127] Optionally, the raw material of the coating includes at least one of zirconia ceramics, polycarbonate, alumina, boehmite, polymethyl methacrylate, aramid fiber and polyvinylidene fluoride.

[0128] Different coating areas can use coatings with the same formulation, and the formulation can be obtained by mixing 70% of aluminum oxide and 30% of polycarbonate to obtain a slurry.

[0129] In the embodiments of the present application, the raw materials of the coating include at least one of zirconium oxide ceramics, polycarbonate, alumina, boehmite, polymethyl methacrylate, aramid fiber and polyvinylidene fluoride, and the coating formula can be designed by at least one of these raw materials to control the ionic conductivity of each coating area.

[0130] Optionally, the ionic conductivity of the separator 113 in each coated area increases from the middle to both sides by controlling at least one of the formula of the raw material, the coating weight and the compaction density of the coating layer in each coated area.

[0131] The embodiments of the present application control the ionic conductivity of each coating area by controlling at least one of the formula of the raw materials, the coating weight and the compaction density of the coating of each coating area, thereby achieving differentiated settings of the ionic conductivity of different coating areas.

[0132] Optionally, applying coatings to multiple coating regions on the base film 600 to obtain the diaphragm 113 includes applying coatings of different thicknesses to multiple coating regions on the base film 600 and compacting the coatings to obtain the diaphragm 113 .

[0133] The coating can be compacted by using a pressure roller, and the coating can be compacted by setting different pressures of the pressure roller.

[0134] In the embodiment of the present application, coatings of different thicknesses are applied to multiple coating areas on the base film 600, and the coatings are compacted to obtain the diaphragm 113. Differentiated settings of ionic conductivity can be achieved by applying coatings of different compaction densities or different coating weights to the multiple coating areas.

[0135] Continue to refer to Figures 6 to 8 As shown, the coating process of the base film 600 can be carried out by using a coating device 500, where the coating device 500 includes a plurality of coating systems, each of which can coat a coating area. Specifically, the coating device 500 includes a first coating system 501, a second coating system 502, a third coating system 503, a fourth coating system 504, and a fifth coating system 505, wherein the first coating system 501 includes a first coating channel 5011 and a first coating port 5012, the first coating port 5012 is used to spray the first slurry onto the base film 600 to form a first slurry layer 5013 on the base film 600, and the second coating system 502 includes a second coating channel 5021 and a second coating port 5022, the second coating port 5022 is used to spray the first slurry onto the base film 600 to form a first slurry layer 5013 on the base film 600. The third coating system 503 includes a third coating channel 5031 and a third coating port 5032, and the third coating port 5032 is used to spray the third slurry onto the base film 600 to form a third slurry layer 5033 on the base film 600. The fourth coating system 504 includes a fourth coating channel 5041 and a fourth coating port 5042, and the fourth coating port 5042 is used to spray the fourth slurry onto the base film 600 to form a fourth slurry layer 5043 on the base film 600. The fifth coating system 505 includes a fifth coating channel 5051 and a fifth coating port 5052, and the fifth coating port 5052 is used to spray the fifth slurry onto the base film 600 to form a fifth slurry layer 5053 on the base film 600.

[0136] The first slurry, the second slurry, the third slurry, the fourth slurry and the fifth slurry here can be slurries of the same formula or slurries of different formulas.

[0137] It should be noted that the first coating system 501, the second coating system 502, the third coating system 503, the fourth coating system 504 and the fifth coating system 505 are formed into a target-shaped structure, and each coating system is used to spray slurry.

[0138] After the separator 113 is coated, the battery cell 10 is manufactured through processes such as drying, cold pressing, winding, shelling, liquid injection and formation. The battery cell 10 is tested to further improve the preparation method of the battery cell 10.

[0139] The test results of the diaphragm 113 of the present application are further described in detail below in combination with Examples 1-5 and Comparative Example 1. However, it should be understood that the examples of the present application are only for explaining the present application, not for limiting the present application, and the examples of the present application are not limited to the examples given in the specification. The specific experimental conditions or operating conditions not specified in the examples are made under conventional conditions or under the conditions recommended by the material supplier.

[0140] Embodiment 1 can be operated according to the following steps: using a base film 600 with a thickness of 7 μm, and providing five coating areas on the coating area 1131 on the base film 600, wherein the coating thickness of each coating area can be the same or different, and performing operating condition simulation on the battery cell 10, performing two hundred charge and discharge cycles, that is, the 200cls capacity retention rate in Table 1, wherein the ionic conductivity of the first coating area 11311 is less than the ionic conductivity of the second coating area 11312, the ionic conductivity of the second coating area 11312 is less than the ionic conductivity of the third coating area 11313, the ionic conductivity of the third coating area 11313 is less than the ionic conductivity of the fourth coating area 11314, the ionic conductivity of the fourth coating area 11314 is less than the ionic conductivity of the fifth coating area 11315, and the 200cls capacity retention rate of the battery cell 10 is 87%, wherein the control of the ionic conductivity is achieved by controlling the coating thickness.

[0141] Example 2 has the same operating steps as the above-mentioned Example 1, except that the ionic conductivity of each coating area is different from that in Example 1, and the ionic conductivity of each coating area is smaller than that in the example, wherein the ionic conductivity of the first coating area 11311 is small, and the coating thickness is the largest. The 200cls capacity retention rate of the battery cell 10 is 92%, and the control of the ionic conductivity is achieved by controlling the coating thickness.

[0142] Example 3 has the same operating steps as the above-mentioned Example 1, except that the ionic conductivity of each coating area is the same and less than that in Comparative Example 1, but the roller pressure is greater than that in Comparative Example 1, and the 200cls capacity retention rate of the battery cell 10 is 88%.

[0143] Example 4 has the same operation steps as the above-mentioned Example 1, except that the ion conductivity of each coating area is different from that in Example 1, and the 200 cls capacity retention rate of the battery cell 10 is 93%.

[0144] Example 5 has the same operation steps as the above-mentioned Example 1, except that the ion conductivity of each coating area is different from that in Example 1, and the 200 cls capacity retention rate of the battery cell 10 is 83%.

[0145] Comparative Example 1 has the same operating steps as the above-mentioned Example 1, except that the ionic conductivity of the coating area is the same, and the 200 cls capacity retention rate of the battery cell 10 is 82%.

[0146] The evaluation structures of Examples 1 to 5 and Comparative Example 1 are shown in Table 1 below.

[0147] Table 1. Comparison of test results of different diaphragms

[0148]

[0149] It can be seen from the above results that by setting the coating weight in each coating area differently, each coating area can have a different ion conductivity, thereby improving the capacity retention rate of the battery cell 10 .

[0150] 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.

[0151] The first aspect of the embodiment of the present application proposes a method for preparing a diaphragm 113, the diaphragm 113 is applied to a battery cell 10, and a coating area 1131 is provided on the diaphragm 113. The method for preparing the diaphragm 113 includes obtaining the operating parameter distribution of the coating area 1131 of the battery cell 10 in the test state; dividing it into multiple coating areas according to the operating parameter distribution; providing a base film 600; and coating the multiple coating areas on the base film 600 to obtain the diaphragm 113, wherein the multiple coating areas are arranged side by side along the width direction of the diaphragm 113, and the ionic conductivity of the diaphragm 113 in each coating area increases from the middle to both sides. Further, dividing the coating area 1131 into multiple coating areas according to the operating parameter distribution includes dividing the coating area 1131 into multiple coating areas according to the temperature distribution, and dividing the multiple coating areas according to the temperature interval, wherein the middle area is the area with the highest average temperature, and the middle area is the area with the lowest ionic conductivity. Further, dividing the coating area 1131 into a plurality of coating areas according to the distribution of the operating parameters also includes determining the area with the highest average temperature as the first coating area 11311; extending from the area with the highest average temperature to both sides along the width direction of the diaphragm, the area with a temperature in the first area range is the second coating area 11312, and the average temperature of the first threshold is lower than the average temperature of the area with the highest average temperature, and the ion conductivity of the second coating area 11312 is greater than or equal to the ion conductivity of the first coating area 11311. Further, extending from the middle area of ​​the coating area 1131 to both sides along the width direction of the diaphragm 113, dividing the coating area according to the temperature interval also includes extending from the second coating area 11312 to the direction away from the area with the highest average temperature along the width direction of the diaphragm 113, the area with a temperature in the second threshold is the third coating area 11313, and the average temperature of the second threshold is lower than the average temperature of the first threshold, and the ion conductivity of the third coating area 11313 is greater than or equal to the ion conductivity of the second coating area 11312. Further, dividing the coating area 1131 into a plurality of coating areas according to the distribution of operating parameters includes dividing the coating area 1131 into a plurality of coating areas according to the capacity retention rate, and dividing the plurality of coating areas according to the interval in which the capacity retention rate is located, wherein the middle area is the area with the lowest capacity retention rate, and the middle area is the area with the lowest ion conductivity. Further, dividing the coating area 1131 into a plurality of coating areas according to the distribution of operating parameters also includes determining the area with the lowest capacity retention rate as the first coating area 11311; extending from the area with the lowest capacity retention rate along the width direction of the diaphragm 113 to both sides, the area with the capacity retention rate in the first area range is the second coating area 11312, and the average capacity retention rate of the first area range is greater than or equal to the average capacity retention rate of the area with the lowest capacity retention rate, and the ion conductivity of the second coating area 11312 is greater than or equal to the ion conductivity of the first coating area 11311.Further, the coating area 1131 is divided into a plurality of coating areas according to the distribution of operating parameters, and further includes extending from the second coating area 11312 in the direction away from the area with the lowest capacity retention rate along the width direction of the diaphragm 113, and the area with the capacity retention rate in the second area range is the third coating area 11313, and the capacity retention rate in the second area range is lower than the capacity retention rate in the first area range, and the ion conductivity of the third coating area 11313 is greater than or equal to the ion conductivity of the second coating area 11312. Further, the base film 600 is a porous structure. Further, coating the plurality of coating areas on the base film 600 to obtain the diaphragm 113 specifically includes coating the base film 600 with a coating device 500, wherein the coating device 500 has a plurality of coating ports, and the plurality of coating ports are arranged side by side along the width direction of the diaphragm 113. Further, the raw material of the coating includes at least one of zirconium oxide ceramic, polycarbonate, aluminum oxide, boehmite, polymethyl methacrylate, aramid fiber and polyvinylidene fluoride. Further, the ionic conductivity of the diaphragm 113 in each coating area increases from the middle to both sides by controlling at least one of the formula of the raw material of the coating of each coating area, the coating weight and the compaction density. Further, coating the multiple coating areas on the base film 600 to obtain the diaphragm 113 includes coating the multiple coating areas on the base film 600 with different thicknesses of coatings; and compacting the coatings to obtain the diaphragm 113.

[0152] The above is only a preferred specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for preparing a diaphragm, wherein the diaphragm is applied to a battery cell and a coating area is provided on the diaphragm, characterized in that: The preparation method of the diaphragm comprises: Obtaining the distribution of operating parameters of the coating area of ​​the battery cell when the battery cell is in a test state; Dividing into a plurality of coating areas according to the distribution of the operating parameters; providing a basement membrane; According to the multiple coating areas, a coating is applied to the base film to obtain the diaphragm, wherein the multiple coating areas are arranged side by side along the width direction of the diaphragm, and along the width direction of the diaphragm, the ionic conductivity of the diaphragm in each coating area increases from the middle to both sides.

2. The method for preparing a diaphragm according to claim 1, characterized in that: The plurality of coating areas are divided according to the distribution of the operating parameters, including: The coating area is divided into the multiple coating regions according to the temperature distribution, and the multiple coating regions are divided according to the temperature interval, wherein the middle region along the width direction of the diaphragm is the region with the highest average temperature, and the middle region is the region with the lowest ion conductivity.

3. The method for preparing a diaphragm according to claim 2, characterized in that: Dividing the coating areas into a plurality of coating areas according to the distribution of the operating parameters also includes: Determine the area with the highest average temperature as the first coating area; Extending from the area with the highest average temperature to both sides along the width direction of the diaphragm, the area where the temperature is at the first threshold is the second coating area, and the average temperature of the first threshold is lower than the average temperature of the area with the highest average temperature, and the ion conductivity of the second coating area is greater than or equal to the ion conductivity of the first coating area.

4. The method for preparing a diaphragm according to claim 3, characterized in that: Extending from the middle area of ​​the coating area to both sides along the width direction of the diaphragm, the coating area is divided according to the temperature range and further includes: Along the width direction of the diaphragm, extending from the second coating area in the direction away from the area with the highest average temperature, the area where the temperature is at the second threshold is the third coating area, and the average temperature of the second threshold is lower than the average temperature of the first threshold, and the ion conductivity of the third coating area is greater than or equal to the ion conductivity of the second coating area.

5. The method for preparing a diaphragm according to claim 1, characterized in that: The plurality of coating areas are divided according to the distribution of the operating parameters, including: The coating area is divided into a plurality of coating regions according to the capacity retention rate, and the plurality of coating regions are divided according to the interval in which the capacity retention rate is located, wherein the middle region along the width direction of the diaphragm is the region with the lowest capacity retention rate, and the middle region is the region with the lowest ion conductivity.

6. The method for preparing a diaphragm according to claim 5, characterized in that: Dividing the coating areas into a plurality of coating areas according to the distribution of the operating parameters also includes: Determining the region with the lowest capacity retention rate as the first coating region; Extending to both sides along the width direction of the diaphragm from the area with the lowest capacity retention rate, the area with the capacity retention rate within the first area range is the second coating area, and the average capacity retention rate of the first area range is greater than the average capacity retention rate of the area with the lowest capacity retention rate, and the ion conductivity of the second coating area is greater than or equal to the ion conductivity of the first coating area.

7. The method for preparing a diaphragm according to claim 6, characterized in that: Dividing the coating areas into a plurality of coating areas according to the distribution of the operating parameters also includes: Along the width direction of the diaphragm, extending from the second coating area in the direction away from the area with the lowest capacity retention rate, the area with a capacity retention rate within the second area range is the third coating area, and the capacity retention rate within the second area range is lower than the capacity retention rate within the first area range, and the ion conductivity of the third coating area is greater than or equal to the ion conductivity of the second coating area.

8. The method for preparing a diaphragm according to any one of claims 1 to 7, characterized in that: The base film has a porous structure.

9. The method for preparing a diaphragm according to any one of claims 1 to 7, characterized in that: The method of coating the plurality of coating regions on the base film to obtain the diaphragm specifically includes: The base film is coated by a coating device, wherein the coating device has a plurality of coating ports, and the plurality of coating ports are arranged side by side along the width direction of the diaphragm.

10. The method for preparing a diaphragm according to any one of claims 1 to 7, characterized in that: The raw material of the coating includes at least one of zirconia ceramics, polycarbonate, alumina, boehmite, polymethyl methacrylate, aramid fiber and polyvinylidene fluoride.

11. The method for preparing a diaphragm according to any one of claims 1 to 7, characterized in that: The ionic conductivity of the separator in each coated region increases from the middle to both sides by controlling at least one of the formula of the raw materials, the coating weight and the compaction density of the coating layer in each coated region.

12. The method for preparing a diaphragm according to any one of claims 1 to 7, characterized in that: The method of coating the plurality of coating regions on the base film to obtain the diaphragm comprises: The coatings with different thicknesses are respectively coated on the multiple coating areas on the base film; and the coatings are compacted to obtain the diaphragm. 13 . A battery cell, comprising a separator manufactured by the method for preparing a separator according to claim 1 .

14. A battery device, characterized in that: include: Battery box: and The battery cell according to claim 13, wherein the battery cell is disposed in the battery box.

15. An electrical equipment, characterized in that: The battery device as claimed in claim 14 is used to store or provide electrical energy.

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