Preparation method of pole piece, 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 pole piece, a battery monomer, a battery device and electric equipment. The preparation method comprises the following steps: acquiring at least one test temperature value of a coating area when a battery monomer is in a test state, dividing the coating area into a plurality of coating areas according to the test temperature value, acquiring the capacity distribution of the coating area when the battery monomer is in the test state, and determining the capacity variation of the coating area according to the capacity distribution of the coating area, according to the capacity variation of each coating area, the coating area with the minimum capacity variation is determined as a reference coating area, and coating parameters of other coating areas are adjusted according to coating parameters of the reference coating area; and preparing the pole piece according to the adjusted coating parameters of the coating area. And the pole piece has different initial capacities in different coating areas, and the residual capacities in different areas are relatively balanced, so that the capacity attenuation of the single battery is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of battery production, and in particular to a method for preparing a pole piece, 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 in the coated area of ​​the electrode at different positions, 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 pole piece, a battery cell, a battery device and an electrical equipment, which solves the problem of excessive capacity decay of the electrode assembly caused by inconsistent capacity decay at different positions of the coating area of ​​the pole piece in the prior art.

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

[0007] Acquire at least one test temperature value of the coating area of ​​the battery cell when the battery cell is in a test state, and divide the coating area into a plurality of coating areas according to the test temperature value;

[0008] Obtaining the capacity distribution of the coating area of ​​the battery cell in the test state, and determining the capacity change of the coating area according to the capacity distribution of the coating area;

[0009] According to the capacity change of each coating area, determine the coating area with the least capacity change as the reference coating area, and adjust the coating parameters of other coating areas according to the coating parameters of the reference coating area;

[0010] The electrode is prepared according to the coating parameters of the adjusted coating area.

[0011] The preparation method of the electrode of the embodiment of the present application can determine the coating area with the smallest capacity change as the reference coating area according to the temperature test value of the coating area of ​​the electrode and the capacity change of the coating area, and according to the capacity change of each coating area, adjust the coating parameters of other coating areas according to the coating parameters of the reference coating area, and prepare the electrode according to the coating parameters of the adjusted coating area. This can make the electrode have different initial capacities in different coating areas. Since the reaction rates of different coating areas are different, the initial capacity of the area with the fastest reaction rate is the largest, and the initial capacity of the area with the slowest reaction rate is the smallest. This can make the residual capacity of the electrode after full discharge in different coating areas more balanced, thereby reducing the capacity attenuation of the battery cell.

[0012] In some embodiments of the present application, the coating parameters include at least one of the formulation, compaction density and coating weight of the coating slurry.

[0013] In the embodiments of the present application, by including coating parameters in the formula of the coating slurry, at least one of the compaction density and the coating weight, an adjusted electrode can be prepared by adjusting at least one of the formula of the coating slurry, the compaction density and the coating weight, so that the residual capacity of the electrode in different areas after full discharge is relatively balanced, thereby reducing the capacity attenuation of the battery cell.

[0014] In some embodiments of the present application, determining the capacity change of the coating area according to the capacity distribution of the coating area specifically includes obtaining the difference between the initial capacity of the coating area and the residual capacity of the coating area to determine the capacity change of the coating area.

[0015] The embodiment of the present application determines the capacity change of the coating area by obtaining the difference between the initial capacity of the coating area and the residual capacity of the coating area. The capacity change of the coating area can be determined, and the coating parameters can be adjusted according to the capacity change of the coating area in different areas.

[0016] In some embodiments of the present application, the coating area is divided into multiple coating areas according to the test temperature value, including extending from the middle area of ​​the coating area to both sides along the width direction of the pole piece, and the coating area is divided according to the temperature range, wherein the middle area is the area with the highest average temperature.

[0017] The embodiment of the present application extends from the middle area of ​​the coating area to both sides along the width direction of the pole piece, and divides the coating area according to the temperature range, wherein the middle area is the area with the highest average temperature. The coating area can be divided into multiple coating areas along the width direction of the pole piece according to the temperature distribution, and different coating parameters are adopted to control each coating area, so as to improve the balance of the residual capacity of the pole piece in different areas.

[0018] In some embodiments of the present application, extending from the middle area of ​​the coating area to both sides along the width direction of the pole piece, dividing the coating area according to the temperature range 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 pole piece, the area with the temperature in the first interval is the second coating area, and the average temperature in the first interval is lower than the average temperature of the area with the highest average temperature.

[0019] The embodiments of the present application extend from the middle area of ​​the coating area to both sides along the width direction of the pole piece, and divide the coating area according to the temperature range, including 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 pole piece, the area with the temperature in the first interval range is the second coating area, and the average temperature in the first interval range is lower than the average temperature of the area with the highest average temperature. Then, the coating area can be divided into the first coating area and the second coating area according to the different average temperatures along the width direction of the pole piece, so that the first coating area and the second coating area can be coated according to different coating parameters respectively, thereby realizing zoned coating of the coating area.

[0020] 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 pole piece, and 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 pole piece. The area with a temperature in the second interval is the third coating area, and the average temperature of the second interval is lower than the average temperature of the first interval.

[0021] In the embodiment of the present application, a coating region is provided extending from the second coating region in a direction away from the region with the highest average temperature along the width direction of the pole piece, and the region with a temperature in the second interval is the third coating region, and the average temperature of the second interval is lower than the average temperature of the first interval. Then, the first coating region, the second coating region and the third coating region can be coated respectively according to different coating parameters, thereby realizing zoned coating of the coating area.

[0022] In some embodiments of the present application, based on the capacity change of each coating area, the coating area with the least capacity change is determined as the reference coating area, and the coating parameters of other coating areas are adjusted according to the coating parameters of the reference coating area, including increasing the initial capacity of the first coating area according to the difference between the capacity change of the first coating area and the capacity change of the third coating area, and increasing the initial capacity of the second coating area according to the difference between the capacity change of the second coating area and the capacity change of the third coating area, so that the residual capacities of the first coating area, the second coating area and the third coating area are consistent, wherein the third coating area is the coating area with the least capacity change, and the third coating area is the reference coating area.

[0023] The embodiments of the present application increase the initial capacity of the first coating area according to the difference between the capacity change of the first coating area and the capacity change of the third coating area, and increase the initial capacity of the second coating area according to the difference between the capacity change of the second coating area and the capacity change of the third coating area, so that the residual capacity of the first coating area, the second coating area and the third coating area are consistent, so that the residual margin of the coating area of ​​the pole piece in different areas can be basically consistent, thereby reducing the capacity attenuation of the battery cell.

[0024] In some embodiments of the present application, increasing the initial capacity of the first coating area is achieved by increasing the proportion of at least one high specific capacity material in the coating slurry of the first coating area, increasing the coating weight of the first coating area, and increasing the compaction density of the first coating area, wherein the specific capacity of the high specific capacity material is greater than 500 mAh / g.

[0025] In the embodiments of the present application, increasing the initial capacity of the first coating area is achieved by increasing the proportion of at least one high specific capacity material in the coating slurry of the first coating area, increasing the coating weight of the first coating area, and increasing the compaction density of the first coating area. This makes it convenient to adjust the initial capacity of the first coating area and increase the initial capacity of the first coating area.

[0026] In some embodiments of the present application, increasing the initial capacity of the second coating area is achieved by increasing the proportion of at least one high specific capacity material in the coating slurry of the second coating area, increasing the coating weight of the second coating area, and increasing the compaction density of the second coating area, wherein the specific capacity of the high specific capacity material is greater than 500 mAh / g.

[0027] In the embodiments of the present application, the initial capacity of the second coating area is increased by increasing the proportion of at least one high specific capacity material in the coating slurry of the second coating area, increasing the coating weight of the second coating area, and increasing the compaction density of the second coating area. This can facilitate the adjustment of the initial capacity of the second coating area and increase the initial capacity of the second coating area.

[0028] In some embodiments of the present application, according to the capacity change of each coating area, determining the coating area with the least capacity change as the reference coating area, and adjusting the coating parameters of other coating areas according to the coating parameters of the reference coating area includes:

[0029] Determine that the electrode is a cathode electrode, reduce the initial capacity of the first coating area according to the difference between the capacity change of the first coating area and the capacity change of the third coating area, and reduce the initial capacity of the second coating area according to the difference between the capacity change of the second coating area and the capacity change of the third coating area, so that the residual capacities of the first coating area, the second coating area and the third coating area are consistent, wherein the third coating area is the coating area with the least capacity change.

[0030] The embodiments of the present application reduce the initial capacity of the first coating area according to the difference between the capacity change of the first coating area and the capacity change of the third coating area, and reduce the initial capacity of the second coating area according to the difference between the capacity change of the second coating area and the capacity change of the third coating area, so that the residual capacity of the first coating area, the second coating area and the third coating area are consistent, so that the residual margin of the coating area of ​​the electrode in different areas can be basically consistent, thereby reducing the capacity attenuation of the battery cell.

[0031] In some embodiments of the present application, reducing the initial capacity of the first coating area is achieved by increasing the proportion of at least one low specific capacity material in the coating slurry of the first coating area, reducing the coating weight of the first coating area, and reducing the compaction density of the first coating area, and the specific capacity of the low specific capacity material is less than or equal to 500mAh / g.

[0032] In the embodiments of the present application, the initial capacity of the first coating area is reduced by increasing the proportion of at least one low specific capacity material in the coating slurry of the first coating area, reducing the coating weight of the first coating area, and reducing the compaction density of the first coating area. This can facilitate the adjustment of the initial capacity of the first coating area and reduce the initial capacity of the first coating area.

[0033] In some embodiments of the present application, reducing the initial capacity of the second coating region is achieved by increasing the proportion of at least one low specific capacity material in the coating slurry of the second coating region, reducing the coating weight of the second coating region, and reducing the compaction density of the second coating region.

[0034] In the embodiments of the present application, the initial capacity of the second coating area is reduced by increasing the proportion of at least one low specific capacity material in the coating slurry of the second coating area, reducing the coating weight of the second coating area, and reducing the compaction density of the second coating area. This can facilitate the adjustment of the initial capacity of the second coating area and reduce the initial capacity of the second coating area.

[0035] In some embodiments of the present application, obtaining the temperature distribution of the coating area is achieved by disposing a temperature sensor on the surface of the coating area.

[0036] In the embodiment of the present application, a temperature sensor is arranged on the surface of the coating area to obtain the temperature distribution of the coating area, thereby achieving accurate measurement of the temperature of the coating area and facilitating zoning according to the temperature range.

[0037] In some embodiments of the present application, the capacity change of the coating area is determined according to the capacity distribution of the coating area by making button batteries with disassembled pole pieces and performing discharge tests.

[0038] In the embodiment of the present application, the disassembled pole piece is made into a button-type battery to determine the residual capacity of the coating area. Then, the capacity change of different areas of the coating area can be determined according to the initial capacity and residual capacity of the pole piece, and the test is convenient and accurate.

[0039] In some embodiments of the present application, preparing the electrode according to the adjusted coating parameters of the coating area includes coating the electrode using 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 electrode.

[0040] In an embodiment of the present application, a coating device is used to coat the electrode piece, wherein the coating device has multiple coating ports, and the multiple coating ports are arranged side by side along the width direction of the electrode piece. The electrode piece can be coated sequentially through the multiple coating ports, thereby improving the coating efficiency of the electrode piece.

[0041] A second aspect of the embodiments of the present application provides a battery cell, which includes a pole piece manufactured by the pole piece manufacturing method mentioned in the above embodiments.

[0042] 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.

[0043] 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.

[0044] 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

[0045] 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:

[0046] Figure 1 A schematic diagram of the structure of an electrical device provided in some embodiments of the present application;

[0047] Figure 2 A schematic diagram of the structure of a battery device provided in some embodiments of the present application;

[0048] Figure 3 A schematic diagram of the structure of a battery cell provided in some embodiments of the present application;

[0049] Figure 4 A schematic diagram of the structure of an electrode assembly provided in some embodiments of the present application;

[0050] Figure 5 A schematic diagram of the structure of a pole piece provided in some embodiments of the present application;

[0051] Figure 6 A schematic diagram of the structure of a coating device provided in some embodiments of the present application;

[0052] Figure 7 for Figure 6 A schematic cross-sectional structural diagram of the coating device shown in FIG. 1 along the AA cross section;

[0053] Figure 8 for Figure 5 The pole piece shown in FIG. is a schematic diagram of the structure at a second viewing angle (the pole ear is not shown);

[0054] Fig. 9 A flow chart of a method for preparing a pole piece provided in some embodiments of the present application.

[0055] The reference numerals are as follows:

[0056] 100, battery device; 200, vehicle; 300, controller; 400, motor;

[0057] 10. Battery cell; 11. Electrode assembly; 111. Positive electrode sheet; 1111. Positive electrode coating area; 112. Negative electrode sheet; 1121. Negative electrode coating area; 113. Separator; 114. First coating area; 115. Second coating area; 116. Third coating area; 117. Tab; 12. Shell; 121. Shell body; 122. End cover;

[0058] 20. Battery box; 21. First box; 22. Second box; 23. Accommodation space;

[0059] 500, coating device; 501, first coating system; 5011, first coating channel; 5012, first coating port; 5013, first slurry coating area; 502, second coating system; 5021, second coating channel; 5022, second coating port; 5023, second slurry coating area; 503, third coating system; 5031, third coating channel; 5032, third coating port; 5033, third slurry coating area; 504, fourth coating system; 5041, fourth coating channel; 5042, fourth coating port; 5043, fourth slurry coating area;

[0060] 600, base material;

[0061] XX, width direction of the pole piece;

[0062] YY, length direction of the pole piece. DETAILED DESCRIPTION

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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).

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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 in the coated area of ​​the electrode at different positions, and the capacity of the electrode assembly is prone to decay too quickly.

[0078] In order to solve this problem, an embodiment of the present application proposes a method for preparing a pole piece, wherein a coating area is provided on the pole piece, and the pole piece is applied to a battery cell. The preparation method includes obtaining at least one test temperature value of the coating area of ​​the battery cell when it is in a test state, and dividing the coating area into a plurality of coating areas according to the test temperature value; obtaining the capacity distribution of the coating area of ​​the battery cell when it is in a test state, and determining the capacity change of the coating area according to the capacity distribution of the coating area; determining the coating area with the least capacity change as a reference coating area according to the capacity change of each coating area, and adjusting the coating parameters of other coating areas according to the coating parameters of the reference coating area; and preparing the pole piece according to the coating parameters of the adjusted coating area. The method for preparing the electrode of the embodiment of the present application can determine the coating area with the least capacity change as the reference coating area according to the test temperature value of the coating area of ​​the electrode and the capacity change of the coating area, and according to the capacity change of each coating area, adjust the coating parameters of other coating areas according to the coating parameters of the reference coating area, and prepare the electrode according to the coating parameters of the adjusted coating area. This can make the electrode have different initial capacities in different coating areas, so that the residual capacity of the electrode after full discharge in different areas is relatively balanced, thereby reducing the capacity attenuation of the battery cell.

[0079] The method for preparing a pole piece in the embodiment of the present application can be used in the production process of a battery cell to prepare a pole piece with a coating area arranged in a partitioned manner.

[0080] The structure in the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0081] For the convenience of description, the following embodiments are described by taking the electric device as a vehicle as an example.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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 .

[0088] 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 .

[0089] 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 .

[0090] 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.

[0091] 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.

[0092] Combined with Figure 4 and Figure 5 As shown, an embodiment of the present application further provides a battery cell 10, the battery cell 10 includes an electrode assembly 11 and a separator 113, the electrode assembly 11 includes a negative electrode plate 112 and a positive electrode plate 111, the positive electrode plate 111 includes a positive electrode coating area 1111, and the negative electrode plate 112 includes a negative electrode coating area 1121, wherein both the positive electrode plate 111 and the negative electrode plate 112 are provided with a pole ear 117.

[0093] 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 117 of the electrode assembly 11 through the adapter.

[0094] like Fig. 9 As shown, the embodiment of the present application also proposes a method for preparing a pole piece, wherein a coating area is provided on the pole piece, and the pole piece is applied to a battery cell 10. The pole piece here can be a positive pole piece 111 or a negative pole piece 112. The preparation method includes:

[0095] S91, obtaining at least one test temperature value of the coating area of ​​the battery cell 10 when the battery cell 10 is in a test state, and dividing the coating area into a plurality of coating areas according to the test temperature value;

[0096] S92, obtaining the capacity distribution of the coating area of ​​the battery cell 10 in the test state, and determining the capacity change of the coating area according to the capacity distribution of the coating area;

[0097] S93, according to the capacity change of each coating area, determining the coating area with the least capacity change as the reference coating area, and adjusting the coating parameters of other coating areas according to the coating parameters of the reference coating area;

[0098] S94, preparing the electrode according to the adjusted coating parameters of the coating area.

[0099] When the battery cell 10 is in a test state, it is usually charged at a low rate and discharged at a high power. This may cause the electrode assembly 11 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.

[0100] In S91, obtaining at least one test temperature value of the coating area of ​​the battery cell 10 in the test state can be achieved by setting multiple temperature sensors in the coating area. 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.

[0101] In S92, the capacity change can be a relative value or an absolute value. The absolute value can be obtained by measuring the difference between the capacity of the electrode in a fresh state and the residual capacity of the electrode, or the capacity change can be determined by the ratio of the difference between the capacity of the electrode in a fresh state and the residual capacity of the electrode to the capacity of the electrode in a fresh state. The capacity change here is usually the capacity reduction.

[0102] In S93, based on the capacity change of each coating area, the coating area with the smallest capacity change is determined as the baseline coating area, and the coating parameters of other coating areas are adjusted according to the coating parameters of the baseline coating area. That is to say, there are multiple coating areas, and the capacity changes in the multiple coating areas are different. Therefore, the capacity change of each coating area is determined by comparison with the coating area with the smallest capacity change. The coating parameters of the baseline coating area here can be used as the baseline parameters for adjustment.

[0103] In S94, the electrode is prepared according to the coating parameters of the adjusted coating area, which is specifically achieved by increasing the initial capacity of the area with a larger capacity change, which will be described in more detail later.

[0104] The method for preparing the electrode of the embodiment of the present application can determine the coating area with the least capacity change as the reference coating area according to the temperature distribution of the coating area of ​​the electrode and the capacity change of the coating area, and according to the capacity change of each coating area, adjust the coating parameters of other coating areas according to the coating parameters of the reference coating area, and prepare the electrode according to the coating parameters of the adjusted coating area. This can make the electrode have different initial capacities in different coating areas. Since the reaction rates of different coating areas are different, the initial capacity of the area with the fastest reaction rate is the largest, and the initial capacity of the area with the slowest reaction rate is the smallest. This can make the residual capacity of the electrode after full discharge in different coating areas more balanced, thereby reducing the capacity attenuation of the battery cell 10.

[0105] Optionally, the coating parameters include at least one of a formulation of the coating slurry, a compaction density and a coating weight.

[0106] It should be noted that the formula of the coating slurry is different for the cathode and anode plates. For example, for the anode plate, raw materials such as anode high-capacity materials, graphite, binders, plasticizers and conductive agents can be used. When the initial capacity needs to be increased, the proportion of high-capacity materials can be increased. Among them, high-capacity materials can be materials such as titanium dioxide, tin dioxide and iron oxide, and the content of graphite can be reduced. For the cathode plate, nickel-cobalt-manganese ternary materials, cathode high-capacity materials, binders, conductive agents and plasticizers can be used.

[0107] The compaction density refers to the density of the active material layer after it is coated and compacted by a roller or other equipment. The unit can be g / cm 3 In some embodiments, the compaction density of the active material layer may be in the range of 2.5 g / cm 3 Up to 5g / cm 3 Of course, the compaction density of battery cells 10 made of different materials may be different, which will not be listed one by one in this embodiment.

[0108] The coating weight refers to the coating weight corresponding to each detection position in the electrode. The coating weight can be obtained in any suitable manner, for example, a preset collection device such as a thickness gauge, a weight detector, an area density meter, etc. The coating weight data can refer to weight or thickness, etc.

[0109] In the embodiment of the present application, by including at least one of the coating slurry formula, compaction density and coating weight as coating parameters, an adjusted electrode can be prepared by adjusting at least one of the coating slurry formula, compaction density and coating weight, so that the residual capacity of the electrode in different areas after full discharge is relatively balanced, thereby reducing the capacity attenuation of the battery cell 10.

[0110] Optionally, determining the capacity change of the coating area according to the capacity distribution of the coating area specifically includes obtaining a difference between an initial capacity of the coating area and a residual capacity of the coating area to determine the capacity change of the coating area.

[0111] The initial capacity of the coating area can be replaced by the theoretical capacity. For the positive electrode sheet 111, the weight of the substrate 600 can be subtracted from the weight of the positive electrode sheet 111 to obtain the weight of the active material, and then multiplied by 140 mAh / g (lithium cobalt oxide) to obtain the theoretical capacity. For the negative electrode sheet 112, it can be estimated as 1.05 to 1.1 times the positive electrode sheet 111, or it can be estimated by a similar method, wherein the weight of the active material is then multiplied by 300 mAh / g for calculation.

[0112] The embodiment of the present application determines the capacity change of the coating area by obtaining the difference between the initial capacity of the coating area and the residual capacity of the coating area. The capacity change of the coating area can be determined, and the coating parameters can be adjusted according to the capacity change of the coating area in different areas.

[0113] More specifically, the residual capacity of the coating area can be obtained by a discharge test. Specifically, the battery cell 10 can be disassembled to obtain the disassembled pole piece, and then the pole piece can be made into a button battery to achieve detection. That is to say, the capacity change of the coating area can be determined according to the capacity distribution of the coating area. The residual capacity can be detected by making the disassembled pole piece into a button battery, and the capacity change can be determined by comparing it with the initial capacity. The button battery mentioned here is a button-shaped battery, which can be used to evaluate the residual capacity of the pole piece.

[0114] In the embodiment of the present application, the residual capacity of the coating area is determined by making the disassembled electrode into a button battery. According to the difference between the initial capacity and the residual capacity, the capacity change of different areas of the coating area can be determined, and the test is convenient and accurate.

[0115] The specific process of the discharge test includes the following steps:

[0116] Disassemble the battery cell 10 to obtain the disassembled electrode piece;

[0117] Soak the disassembled electrode in dimethyl carbonate for 3 to 5 minutes to remove surface impurities, then wipe off the active material on one side, leaving only the active material on the other side;

[0118] Cut the electrode into 5 to 10 discs, and select 5 discs with qualified weight;

[0119] Place the qualified disc into the positive side of the buckle battery housing with a gasket placed in advance, with the coated surface facing away from the positive electrode. Then drip 1-2 drops of electrolyte on the positive electrode plate 111, then place the diaphragm 113 and drip 1-2 drops of electrolyte, then place the lithium sheet, gasket and spring, and finally place the buckle battery negative side housing, and seal it with a sealing machine after assembling.

[0120] The active material content is calculated based on the weighed weight of the small disc, and the charge and discharge current required for charging and discharging is calculated based on the estimated gram capacity of the active material to conduct a charge and discharge test.

[0121] Alternatively, if Figure 5 As shown, according to the temperature distribution of the coating area, the coating area is divided into multiple coating areas, including extending from the middle area of ​​the coating area to both sides along the width direction of the pole piece, and the coating area is divided according to the temperature range, wherein the middle area is the area with the highest average temperature.

[0122] exist Figure 5In the figure, the XX direction is the width direction of the electrode sheet, and the YY direction is the length direction of the electrode sheet. When the electrode sheet is in a wound state, the XX direction is the height direction of the electrode assembly 11. The middle area refers to the middle position of the coating area along the XX direction. Considering that the length directions of the positive electrode sheet 111 and the negative electrode sheet 112 are consistent, the length direction of the positive electrode sheet 111 or the negative electrode sheet 112 can be used to represent the length direction of the electrode sheet. In addition, the width directions of the positive electrode sheet 111 and the negative electrode sheet 112 are also consistent, and the width direction of the positive electrode sheet 111 or the negative electrode sheet 112 can be used to represent the width direction of the electrode sheet.

[0123] The embodiment of the present application extends from the middle area of ​​the coating area to both sides along the width direction of the pole piece, and divides the coating area according to the temperature range, wherein the middle area is the area with the highest average temperature. The coating area can be divided into multiple coating areas along the width direction of the pole piece according to the temperature distribution, and different coating parameters are adopted to control each coating area, so as to improve the balance and consistency of the residual capacity of the pole piece in different areas.

[0124] Optionally, continue to refer to Figure 5 and Figure 7 As shown, extending from the middle area of ​​the coating area to both sides along the width direction of the pole piece, the coating area is divided according to the temperature range, including determining the area with the highest average temperature as the first coating area 114; extending from the area with the highest average temperature to both sides along the width direction of the pole piece, the area with the temperature in the first interval range is the second coating area 115, and the average temperature in the first interval range is lower than the average temperature of the area with the highest average temperature.

[0125] It should be noted that the number of the second coating area 115 is two, and they are symmetrically arranged on both sides of the first coating area 114 along the XX direction, wherein the temperature of the first coating area 114 is an interval range, and the temperature of the second coating area 115 is another interval range, for example, the temperature of the first coating area 114 is greater than or equal to 50 and less than 60 degrees Celsius, and the temperature of the second coating area 115 is greater than or equal to 41 and less than 48 degrees Celsius, wherein the average temperature of the second coating area 115 is 44.5 degrees Celsius, and the average temperature of the area with the highest average temperature is 51.5 degrees Celsius.

[0126] The embodiment of the present application extends from the middle area of ​​the coating area to both sides along the width direction of the pole piece, and divides the coating area according to the temperature interval, including determining the area with the highest average temperature as the first coating area 114; extending from the area with the highest average temperature to both sides along the width direction of the pole piece, the area with the temperature in the first interval range is the second coating area 115, and the average temperature in the first interval range is lower than the average temperature of the area with the highest average temperature. Then, the coating area can be divided into the first coating area 114 and the second coating area 115 according to the different average temperatures along the width direction of the pole piece, so that the first coating area 114 and the second coating area 115 can be coated according to different coating parameters respectively, thereby realizing zoned coating of the coating area.

[0127] Alternatively, if Figure 5 As shown, the coating area extends from the middle area of ​​the coating zone to both sides along the width direction of the pole piece, and the coating area is divided according to the temperature interval, which also includes extending from the second coating area 115 along the width direction of the pole piece in the direction away from the area with the highest average temperature. The area with a temperature in the second interval range is the third coating area 116, and the average temperature of the second interval range is lower than the average temperature of the first interval range, that is, the average temperature of the third coating area 116 is lower than the average temperature of the second coating area 115.

[0128] It can be understood that the number of the third coating areas 116 is two, and they are symmetrically arranged on both sides of the first coating area 114 along the XX direction, and the second coating area 115 is arranged between the first coating area 114 and the third coating area 116, and the second interval range corresponding to the third coating area 116 is greater than or equal to 34 and less than 41 degrees Celsius, and the average temperature of the second interval range is 36.5 degrees Celsius.

[0129] In the embodiment of the present application, a region extending from the second coating region 115 in a direction away from the region with the highest average temperature is arranged along the width direction of the pole piece, and the region with a temperature in the second interval is the third coating region 116, and the average temperature of the second interval is lower than the average temperature of the first interval. Then, the first coating region 114, the second coating region 115 and the third coating region 116 can be coated respectively according to different coating parameters, thereby realizing zoned coating of the coating area.

[0130] Optionally, extending from the middle area of ​​the coating area to both sides along the width direction of the pole piece, dividing the coating area according to the temperature range also includes extending from the third coating area 116 along the width direction of the pole piece in the direction away from the area with the highest average temperature, the area with a temperature in the third interval range is the fourth coating area, and the average temperature in the third interval range is lower than the average temperature in the second interval range.

[0131] There are two fourth coating areas, which are symmetrically arranged on both sides of the first coating area 114 along the XX direction, and the second coating area 115 and the third coating area 116 are arranged between the first coating area 114 and the fourth coating area. At this time, the fourth coating area can be set as the reference coating area.

[0132] It is understandable that, depending on the temperature, the coating area may also be provided with a fifth coating area and a sixth coating area, etc., and the temperature range used in each coating interval may also be set as required, such as the temperature range corresponding to the first coating area 114 is greater than or equal to 53 degrees Celsius and less than 55 degrees Celsius, and the temperature range corresponding to the second coating area 115 is greater than or equal to 51 degrees Celsius and less than 53 degrees Celsius, etc. Other situations are not listed here. At this time, the sixth coating area can be set as the reference coating area.

[0133] Optionally, based on the capacity change of each coating area, the coating area with the least capacity change is determined as the reference coating area, and the coating parameters of other coating areas are adjusted according to the coating parameters of the reference coating area, including increasing the initial capacity of the first coating area 114 according to the difference between the capacity change of the first coating area 114 and the capacity change of the third coating area 116, and increasing the initial capacity of the second coating area 115 according to the difference between the capacity change of the second coating area 115 and the capacity change of the third coating area 116, so that the residual capacities of the first coating area 114, the second coating area 115 and the third coating area 116 are consistent, wherein the third coating area 116 is the coating area with the least capacity change, and the third coating area 116 is the reference coating area.

[0134] The coating area with the least capacity change is the area farthest from the first coating area 114, and the first coating area 114 is the area with the largest capacity change. Therefore, the coating parameters of each coating area need to be adjusted according to the capacity change of the area.

[0135] For example, after testing, the capacity change of the first coating area 114 is 5%, the capacity change of the second coating area 115 is 3%, and the capacity change of the third coating area 116 is 1%. When adjusting the coating parameters, the initial capacity of the first coating area 114 is increased by 4%, and the initial capacity of the second coating area 115 is increased by 2%. In this way, the residual capacity of the first coating area 114, the second coating area 115 and the third coating area 116 after capacity decay can be basically consistent, reducing the situation where the decay is accelerated due to the unevenness of the coating area, and effectively improving the cycle performance and service life of the battery cell 10.

[0136] The embodiments of the present application increase the initial capacity of the first coating area 114 according to the difference between the capacity change of the first coating area 114 and the capacity change of the third coating area 116, and increase the initial capacity of the second coating area 115 according to the difference between the capacity change of the second coating area 115 and the capacity change of the third coating area 116, so that the residual capacity of the first coating area 114, the second coating area 115 and the third coating area 116 are consistent, so that the residual margin of the coating area of ​​the pole piece in different areas can be basically consistent, thereby reducing the capacity attenuation of the battery cell 10.

[0137] Optionally, increasing the capacity of the first coating region 114 is achieved by increasing the proportion of at least one high specific capacity material in the coating slurry of the first coating region 114, increasing the coating weight of the first coating region 114, and increasing the compaction density of the first coating region 114, wherein the specific capacity of the high specific capacity material is greater than 500 mAh / g.

[0138] It should be noted that in the slurry formulation, the types of high specific capacity materials can be two or more, in which case, only the proportion of one of the high specific capacity materials needs to be increased. Alternatively, the proportions of two or more high specific capacity materials can also be increased at the same time.

[0139] Specifically, increasing the initial capacity of the first coating region 114 can be achieved by increasing the proportion of at least one high specific capacity material in the formula, increasing the coating weight of the first coating region 114, and increasing the compaction density of the first coating region 114. In this case, the initial capacity of the first coating region 114 is increased by the combined effect of the two or three.

[0140] Alternatively, increasing the initial capacity of the first coating region 114 can be achieved by increasing the proportion of at least one high specific capacity material in the formulation, increasing the coating weight of the first coating region 114, or increasing the compaction density of the first coating region 114. The initial capacity of the first coating region 114 can be increased by simply changing one parameter.

[0141] In the embodiment of the present application, the initial capacity of the first coating area 114 is increased by increasing the proportion of high-capacity materials in the formula of the coating slurry of the first coating area 114, increasing the coating weight of the first coating area 114, and increasing the compaction density of the first coating area 114. This can facilitate the adjustment of the initial capacity of the first coating area 114 and increase the initial capacity of the first coating area 114.

[0142] In some embodiments of the present application, increasing the initial capacity of the second coating region 115 is achieved by increasing the proportion of at least one high specific capacity material in the coating slurry of the second coating region 115, increasing the coating weight of the second coating region 115, and increasing the compaction density of the second coating region 115, wherein the specific capacity of the high specific capacity material is greater than 500 mAh / g.

[0143] Specifically, increasing the initial capacity of the second coating area 115 can be achieved by increasing the proportion of at least one high specific capacity material in the formula, increasing the coating weight of the second coating area 115, and increasing the compaction density of the second coating area 115. In this case, the initial capacity of the second coating area 115 is increased by the combined effect of the two or three.

[0144] Alternatively, increasing the initial capacity of the second coating region 115 can be achieved by increasing the proportion of at least one high specific capacity material in the formulation, increasing the coating weight of the second coating region 115, or increasing the compaction density of the second coating region 115. The initial capacity of the second coating region 115 can be increased by simply changing one parameter.

[0145] In the embodiment of the present application, the initial capacity of the second coating area 115 is increased by increasing the proportion of at least one high specific capacity material in the coating slurry of the second coating area 115, increasing the coating weight of the second coating area 115, and increasing the compaction density of the second coating area 115. This can facilitate the adjustment of the initial capacity of the second coating area 115 and increase the initial capacity of the second coating area 115.

[0146] For example, for the anode pole piece, at least one high specific capacity material may be titanium dioxide, tin dioxide, iron oxide and other materials, and the capacity can be increased by increasing the proportion of at least one high specific capacity material. For the cathode pole piece, nickel-cobalt-manganese ternary materials, cathode low specific capacity materials, cathode high specific capacity materials, binders, conductive agents and plasticizers can be used, among which the cathode high specific capacity materials may be nickel-cobalt-manganese lithium oxide and nickel-cobalt-aluminum lithium oxide, and the cathode low specific capacity materials include lithium iron phosphate and lithium manganate, and the capacity can be increased or decreased by adjusting the proportion of the materials in the proportion formula.

[0147] Optionally, based on the capacity change of each coating area, the coating area with the least capacity change is determined as the reference coating area, and the coating parameters of other coating areas are adjusted based on the coating parameters of the reference coating area, including determining the electrode as the cathode electrode, reducing the capacity of the first coating area 114 based on the difference between the capacity change of the first coating area 114 and the capacity change of the third coating area 116, and reducing the initial capacity of the second coating area 115 based on the difference between the capacity change of the second coating area 115 and the capacity change of the third coating area 116, so that the residual capacities of the first coating area 114, the second coating area 115 and the third coating area 116 are consistent, wherein the third coating area 116 is the coating area with the least capacity change.

[0148] Here, by reducing the initial capacity of the first coating area 114, the difficulty of lithium ions embedding into the cathode electrode can be increased, so that the remaining power of the cathode electrode in each area after discharge is basically the same.

[0149] The embodiments of the present application reduce the initial capacity of the first coating area 114 according to the difference between the capacity change of the first coating area 114 and the capacity change of the third coating area 116, and reduce the initial capacity of the second coating area 115 according to the difference between the capacity change of the second coating area 115 and the capacity change of the third coating area 116, so that the residual capacity of the first coating area 114, the second coating area 115 and the third coating area 116 are consistent, so that the residual margin of the coating area of ​​the electrode in different areas can be basically consistent, thereby reducing the capacity attenuation of the battery cell 10.

[0150] In some embodiments of the present application, reducing the initial capacity of the first coating area 114 is achieved by increasing the proportion of at least one low specific capacity material in the coating slurry of the first coating area 114, reducing the coating weight of the first coating area 114 and reducing the compaction density of the first coating area 114, and the specific capacity of the low specific capacity material is less than or equal to 500 mAh / g.

[0151] It should be emphasized that in the slurry formulation, the types of low specific capacity materials can be two or more, in which case, only the proportion of one of the low specific capacity materials needs to be increased. Alternatively, the proportions of two or more low specific capacity materials can also be increased at the same time.

[0152] It should be noted that the low specific capacity materials and high specific capacity materials here are relative, and other data can also be used as distinguishing points, such as 450mAh / g or 300mAh / g.

[0153] In the embodiment of the present application, the initial capacity of the first coating area 114 is reduced by increasing the proportion of at least one low specific capacity material in the coating slurry of the first coating area 114, reducing the coating weight of the first coating area 114 and reducing the compaction density of the first coating area 114. This can facilitate the adjustment of the initial capacity of the first coating area 114 and reduce the initial capacity of the first coating area 114.

[0154] In some embodiments of the present application, reducing the initial capacity of the second coating region 115 is achieved by increasing the proportion of at least one low specific capacity material in the coating slurry of the second coating region 115, reducing the coating weight of the second coating region 115, and reducing the compaction density of the second coating region 115.

[0155] In the embodiment of the present application, the initial capacity of the second coating area 115 is reduced by increasing the proportion of at least one low specific capacity material in the coating slurry of the second coating area 115, reducing the coating weight of the second coating area 115 and reducing the compaction density of the second coating area 115. It is convenient to adjust the initial capacity of the second coating area 115 and reduce the initial capacity of the second coating area 115, wherein the initial capacity is also the fresh capacity.

[0156] It should be noted that the reference coating area here can be changed as needed. When there are only three coating areas, the reference coating area is the third coating area 116. When there are four coating areas, the reference coating area is the fourth coating area. Correspondingly, when there are five coating areas, the reference coating area is the fifth coating area. The coating parameters of the reference coating area include formula, coating weight and compaction density, etc., which are the basis for the coating parameters of other coating areas. The coating parameters of the reference coating area can be determined by the coating parameters in the prior art.

[0157] Optionally, obtaining the temperature distribution of the coating area is achieved by arranging a temperature sensor on the surface of the coating area.

[0158] In the embodiment of the present application, a temperature sensor is arranged on the surface of the coating area to obtain the temperature distribution of the coating area, thereby achieving accurate measurement of the temperature of the coating area and facilitating zoning according to the temperature range.

[0159] Alternatively, if Figure 6 and Figure 7 As shown, preparing the electrode according to the coating parameters of the adjusted coating area includes coating the electrode using a coating device 500, 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 electrode.

[0160] The coating device 500 here includes multiple 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 and a fourth coating system 504, 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 substrate 600 to form a first slurry coating area 5013 on the substrate 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 substrate 600. The second slurry forms a second slurry coating area 5023 on the substrate 600. The third coating system 503 includes a third coating channel 5031 and a third coating port 5032. The third coating port 5032 is used to spray the third slurry onto the substrate 600 to form a third slurry coating area 5033 on the substrate 600. The fourth coating system 504 includes a fourth coating channel 5041 and a fourth coating port 5042. The fourth coating port 5042 is used to spray the fourth slurry onto the substrate 600 to form a fourth slurry coating area 5043 on the substrate 600.

[0161] It should be noted that the first coating system 501 , the second coating system 502 , the third coating system 503 and the fourth coating system 504 are formed into a target-shaped structure, and each coating system is used to spray a different slurry.

[0162] The embodiment of the present application coats the electrode piece by using a coating device 500, 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 electrode piece. The electrode piece can be coated sequentially through the multiple coating ports, thereby improving the coating efficiency of the electrode piece.

[0163] After the electrode is coated, it goes through processes such as drying, cold pressing, winding, shelling, liquid injection and formation to produce a battery cell 10, which is tested to further improve the preparation method of the battery cell 10 and adjust coating parameters for different coating areas.

[0164] The test results of the anode electrode sheet 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.

[0165] Embodiment 1 can be operated according to the following steps: using a substrate 600 with a thickness of 6 μm, and providing five coating areas on the coating area on the substrate 600, performing operating condition simulation on the battery cell 10, performing two hundred charge and discharge cycles, testing the temperature distribution of the battery cell 10, and the retention ratio of the residual capacity of the battery cell 10 relative to the initial capacity, that is, the 200cls capacity retention rate in Table 1, wherein the initial capacity of the first coating area 114 is greater than the initial capacity of the second coating area 115, the initial capacity of the second coating area 115 is greater than the initial capacity of the third coating area 116, the initial capacity of the third coating area 116 is greater than the initial capacity of the fourth coating area, the initial capacity of the fourth coating area is greater than the initial capacity of the fifth coating area, and the 200cls capacity retention rate of the battery cell 10 is 87%.

[0166] Example 2 has the same operation steps as the above-mentioned Example 1, except that the initial capacity of each coating area is different from that in Example 1, wherein the fresh capacity of the first coating area 114 is the largest, and the 200cls capacity retention rate of the battery cell 10 is 92%.

[0167] Example 3 has the same operation steps as the above-mentioned Example 1, except that the initial capacity of each coating area is different from that in Example 1, wherein the initial capacity of the first coating area 114 is the largest, and the 200cls capacity retention rate of the battery cell 10 is 88%.

[0168] Example 4 has the same operation steps as the above-mentioned Example 1, except that the initial capacity of each coating area is different from that in Example 1, wherein the initial capacity of the first coating area 114 is the largest, and the 200cls capacity retention rate of the battery cell 10 is 85%.

[0169] Example 5 has the same operation steps as the above-mentioned Example 1, except that the initial capacity of each coating area is different from that in Example 1, wherein the initial capacity of the first coating area 114 is the largest, and the 200cls capacity retention rate of the battery cell 10 is 83%.

[0170] Comparative Example 1 has the same operating steps as the above-mentioned Example 1, except that the initial capacity of the coating area is the same, and the 200 cls capacity retention rate of the battery cell 10 is 82%.

[0171] The evaluation structures of Examples 1 to 5 and Comparative Example 1 are shown in Table 1 below.

[0172] Table 1. Comparison of test results of anode plates

[0173]

[0174] The test results of the cathode electrode sheet of the present application are further described in detail below in combination with Examples 6-10 and Comparative Example 2. 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.

[0175] Example 6 can be operated according to the following steps: a substrate 600 with a thickness of 6 μm is used, and five coating areas are provided on the coating area on the substrate 600. The working condition of the battery cell 10 is simulated, and two hundred charge and discharge cycles are performed to test the temperature distribution of the battery cell 10 and the retention ratio of the residual capacity of the battery cell 10 relative to the initial capacity, that is, the 200c ls capacity retention rate in Table 1, wherein the initial capacity of the first coating area 114 is less than the initial capacity of the second coating area 115, the initial capacity of the second coating area 115 is less than the initial capacity of the third coating area 116, the initial capacity of the third coating area 116 is less than the initial capacity of the fourth coating area, the initial capacity of the fourth coating area is less than the initial capacity of the fifth coating area, and the 200c ls capacity retention rate of the battery cell 10 is 87%.

[0176] Example 7 has the same operation steps as the above-mentioned Example 1, except that the initial capacity of each coating area is different from that in Example 1, wherein the initial capacity of the first coating area 114 is the smallest, and the 200 cls capacity retention rate of the battery cell 10 is 92%.

[0177] Example 8 has the same operation steps as the above-mentioned Example 1, except that the initial capacity of each coating area is different from that in Example 1, wherein the initial capacity of the first coating area 114 is the smallest, and the 200cls capacity retention rate of the battery cell 10 is 88%.

[0178] Example 9 has the same operation steps as the above-mentioned Example 1, except that the initial capacity of each coating area is different from that in Example 1, wherein the initial capacity of the first coating area 114 is the smallest, and the 200cls capacity retention rate of the battery cell 10 is 85%.

[0179] Example 10 has the same operation steps as the above-mentioned Example 1, except that the initial capacity of each coating area is different from that in Example 1, wherein the initial capacity of the first coating area 114 is the smallest, and the 200cls capacity retention rate of the battery cell 10 is 83%.

[0180] Comparative Example 2 has the same operating steps as the above-mentioned Example 7, except that the initial capacity of the coating area is the same, and the 200 cls capacity retention rate of the battery cell 10 is 82%.

[0181] The test results of Examples 6-10 and Comparative Example 2 are shown in Table 2.

[0182] Table 2. Comparison of test results of cathode electrode

[0183]

[0184] From the above results, it can be seen that the pole piece in this embodiment can improve the capacity retention of the battery cell 10, thereby increasing the service life of the battery cell 10, because the coating area of ​​the pole piece is coated in a zoned manner.

[0185] 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.

[0186] The first aspect of the embodiment of the present application proposes a method for preparing a pole piece, on which a coating area is provided, and the pole piece is applied to a battery cell 10, including obtaining the temperature distribution of the coating area of ​​the battery cell 10 when the battery cell 10 is in a test state; obtaining at least one test temperature value of the coating area of ​​the battery cell 10 when the battery cell 10 is in a test state, dividing the coating area into a plurality of coating areas according to the test temperature value, and determining the capacity change of the coating area according to the capacity distribution of the coating area; according to the capacity change of each coating area, determining the coating area with the least capacity change as the reference coating area, adjusting the coating parameters of other coating areas according to the coating parameters of the reference coating area; preparing the pole piece according to the coating parameters of the adjusted coating area. Further, the coating parameters include at least one of the formula, compaction density and coating weight of the coating slurry. Further, determining the capacity change of the coating area according to the capacity distribution of the coating area specifically includes obtaining the difference between the initial capacity of the coating area and the residual capacity of the coating area, and determining the capacity change of the coating area. Further, according to the temperature distribution of the coating area, the coating area is divided into a plurality of coating areas, including extending from the middle area of ​​the coating area to both sides along the width direction of the pole piece, and dividing the coating area according to the temperature interval, wherein the middle area is the area with the highest average temperature. Further, extending from the middle area of ​​the coating area to both sides along the width direction of the pole piece, and dividing the coating area according to the temperature interval includes determining the area with the highest average temperature as the first coating area 114; extending from the area with the highest average temperature to both sides along the width direction of the pole piece, the area with the temperature in the first interval range is the second coating area 115, and the average temperature of the first interval range is lower than the average temperature of the area with the highest average temperature. Further, extending from the middle area of ​​the coating area to both sides along the width direction of the pole piece, and dividing the coating area according to the temperature interval also includes extending from the second coating area 115 to the direction away from the area with the highest average temperature along the width direction of the pole piece, and the area with the temperature in the second interval range is the third coating area 116, and the average temperature of the second interval range is lower than the average temperature of the first interval range. Furthermore, based on the capacity change of each coating area, the coating area with the least capacity change is determined as the reference coating area, and the coating parameters of other coating areas are adjusted based on the coating parameters of the reference coating area, including increasing the initial capacity of the first coating area 114 based on the difference between the capacity change of the first coating area 114 and the capacity change of the third coating area 116, and increasing the initial capacity of the second coating area 115 based on the difference between the capacity change of the second coating area 115 and the capacity change of the third coating area 116, so that the residual capacities of the first coating area 114, the second coating area 115 and the third coating area 116 are consistent.Further, the initial capacity of the first coating region 114 is increased by increasing the proportion of at least one high specific capacity material in the coating slurry of the first coating region 114, increasing the coating weight of the first coating region 114, and increasing the compaction density of the first coating region 114. At least one of the above is achieved, wherein the specific capacity of the high specific capacity material is greater than 500 mAh / g. Further, the initial capacity of the second coating region 115 is increased by increasing the proportion of at least one high specific capacity material in the coating slurry of the second coating region 115, increasing the coating weight of the second coating region 115, and increasing the compaction density of the second coating region 115. At least one of the above is achieved, wherein the specific capacity of the high specific capacity material is greater than 500 mAh / g. Furthermore, according to the capacity change of each coating area, the coating area with the least capacity change is determined as the reference coating area, and the coating parameters of other coating areas are adjusted according to the coating parameters of the reference coating area, including determining the electrode as the cathode electrode, reducing the capacity of the first coating area 114 according to the difference between the capacity change of the first coating area 114 and the capacity change of the third coating area 116, and reducing the capacity of the second coating area 115 according to the difference between the capacity change of the second coating area 115 and the capacity change of the third coating area 116, so that the residual capacities of the first coating area 114, the second coating area 115 and the third coating area 116 are consistent, wherein the third coating area 116 is the coating area with the least capacity change. Further, the initial capacity of the first coating area 114 is reduced by increasing the proportion of at least one low specific capacity material in the coating slurry of the first coating area 114, reducing the coating weight of the first coating area 114 and reducing the compaction density of the first coating area 114. The specific capacity of the low specific capacity material is less than or equal to 500mAh / g. Further, the initial capacity of the second coating area 115 is reduced by increasing the proportion of at least one low specific capacity material in the coating slurry of the second coating area 115, reducing the coating weight of the second coating area 115 and reducing the compaction density of the second coating area 115. The specific capacity of the low specific capacity material is less than or equal to 500mAh / g. Further, the temperature distribution of the coating area is obtained by setting a temperature sensor on the surface of the coating area. Further, the capacity change of the coating area is determined according to the capacity distribution of the coating area by making the disassembled pole piece into a button battery and conducting a discharge test. Furthermore, preparing the electrode according to the adjusted coating parameters of the coating area includes coating the electrode using 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 electrode.

[0187] 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 pole piece, wherein the pole piece is provided with a coating area and the pole piece is applied to a battery cell, characterized in that: The preparation method comprises: Acquire at least one test temperature value of the coating area when the battery cell is in a test state, and divide the coating area into a plurality of coating areas according to the test temperature value; Acquire the capacity distribution of the coating area of ​​the battery cell in the test state, and determine the capacity change of the coating area according to the capacity distribution of the coating area; According to the capacity change of each coating area, determine the coating area with the least capacity change as the reference coating area, and adjust the coating parameters of the other coating areas according to the coating parameters of the reference coating area; The pole piece is prepared according to the adjusted coating parameters of the coating area.

2. The method for preparing a pole piece according to claim 1, characterized in that: The coating parameters include at least one of the formula of the coating slurry, the compaction density and the coating weight.

3. The method for preparing a pole piece according to claim 1, characterized in that: Determining the capacity change of the coating area according to the capacity distribution of the coating area specifically includes: The difference between the initial capacity of the coating area and the residual capacity of the coating area is obtained to determine the capacity change of the coating area.

4. The method for preparing a pole piece according to claim 1, characterized in that: Dividing the coating area into a plurality of coating areas according to the test temperature value comprises: The coating area is extended from the middle area of ​​the coating zone to both sides along the width direction of the pole piece, and the coating area is divided according to the temperature interval, wherein the middle area is the area with the highest average temperature.

5. The method for preparing a pole piece according to claim 4, characterized in that: Extending from the middle area of ​​the coating area to both sides along the width direction of the electrode, the coating area is divided according to the temperature range and includes: Determine the area with the highest average temperature as the first coating area; An area extending from the middle to both sides along the width direction of the pole piece and having a temperature in a first range is a second coating area, and an average temperature in the first range is lower than an average temperature of the area with the highest average temperature.

6. The method for preparing a pole piece according to claim 5, characterized in that: Extending from the middle area of ​​the coating area to both sides along the width direction of the electrode piece, dividing the coating area according to the temperature range also includes: Along the width direction of the pole piece, extending from the second coating area in a direction away from the area with the highest average temperature, the area with a temperature in the second interval is the third coating area, and the average temperature of the second interval is lower than the average temperature of the first interval.

7. The method for preparing a pole piece according to claim 6, characterized in that: According to the capacity change of each coating area, determining the coating area with the least capacity change as the reference coating area, and adjusting the coating parameters of other coating areas according to the coating parameters of the reference coating area includes: Determine that the electrode piece is an anode electrode piece, increase the initial capacity of the first coating area according to the difference between the capacity change of the first coating area and the capacity change of the third coating area, and increase the initial capacity of the second coating area according to the difference between the capacity change of the second coating area and the capacity change of the third coating area, so that the residual capacities of the first coating area, the second coating area and the third coating area are consistent, wherein the third coating area is the coating area with the least capacity change, and the third coating area is the reference coating area.

8. The method for preparing a pole piece according to claim 7, characterized in that: Increasing the initial capacity of the first coating area is achieved by increasing the proportion of at least one high specific capacity material in the coating slurry of the first coating area, increasing the coating weight of the first coating area, and increasing the compaction density of the first coating area, wherein the specific capacity of the high specific capacity material is greater than 500 mAh / g.

9. The method for preparing a pole piece according to claim 7, characterized in that: Increasing the initial capacity of the second coating area is achieved by increasing the proportion of at least one high specific capacity material in the coating slurry of the second coating area, increasing the coating weight of the second coating area, and increasing the compaction density of the second coating area, wherein the specific capacity of the high specific capacity material is greater than 500 mAh / g.

10. The method for preparing a pole piece according to claim 6, characterized in that: According to the capacity change of each coating area, determining the coating area with the least capacity change as the reference coating area, and adjusting the coating parameters of other coating areas according to the coating parameters of the reference coating area includes: Determine that the electrode piece is a cathode electrode piece, reduce the initial capacity of the first coating area according to the difference between the capacity change of the first coating area and the capacity change of the third coating area, and reduce the initial capacity of the second coating area according to the difference between the capacity change of the second coating area and the capacity change of the third coating area, so that the residual capacities of the first coating area, the second coating area and the third coating area are consistent, wherein the third coating area is the coating area with the least capacity change, and wherein the third coating area is the reference coating area.

11. The method for preparing a pole piece according to claim 10, characterized in that: Reducing the initial capacity of the first coating area is achieved by increasing the proportion of at least one low specific capacity material in the coating slurry of the first coating area, reducing the coating weight of the first coating area and reducing the compaction density of the first coating area, and the specific capacity of the low specific capacity material is less than or equal to 500mAh / g.

12. The method for preparing a pole piece according to claim 10, characterized in that: Reducing the initial capacity of the second coating area is achieved by increasing the proportion of at least one low specific capacity material in the coating slurry of the second coating area, reducing the coating weight of the second coating area and reducing the compaction density of the second coating area, and the specific capacity of the low specific capacity material is less than or equal to 500mAh / g.

13. The method for preparing a pole piece according to any one of claims 1 to 12, characterized in that: The temperature distribution of the coating area is obtained by arranging a temperature sensor on the surface of the coating area.

14. The method for preparing a pole piece according to any one of claims 1 to 12, characterized in that: The capacity change amount of the coating area is determined according to the capacity distribution of the coating area by making the disassembled electrode sheet into a button-type battery and performing a discharge test.

15. The method for preparing a pole piece according to any one of claims 4 to 12, characterized in that: Preparing the pole piece according to the adjusted coating parameters of the coating area includes: The pole piece 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 pole piece. 16 . A battery cell, comprising a pole piece manufactured by the method for manufacturing a pole piece according to claim 1 .

17. A battery device, characterized in that: include: Battery box: and The battery cell according to claim 16, wherein the battery cell is disposed in the battery case.

18. An electrical equipment, characterized in that: The battery device as claimed in claim 17 is used to store or provide electrical energy.

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