Positive pole piece and processing method thereof, battery and electric equipment

Abstract

The invention discloses a positive pole piece and a treatment method thereof, a battery and electric equipment, and the treatment method of the positive pole piece comprises the following steps: carrying out combustion treatment on a specified part of the positive pole piece, and the specified part comprises at least part of the surface of a positive active material layer of the positive pole piece. According to the treatment method of the positive pole piece, the surface of the positive pole piece is subjected to combustion treatment, and the floating binder can be ablated and reduced through flame, so that the blockage of the floating binder to pores can be improved, and the electrolyte infiltration performance of the positive pole piece can be effectively improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a positive electrode plate and a processing method thereof, a battery and an electrical device. Background Art

[0002] The electrolyte wetting performance of the positive electrode sheet is a factor that affects battery performance. Improving the electrolyte wetting performance of the positive electrode sheet is beneficial to improving the battery's rate performance, discharge capacity, etc. However, in order to meet the design requirements of high energy density, high cycle stability, etc., the wetting performance of the current positive electrode sheet usually needs to be improved. Summary of the invention

[0003] In view of the above problems, the present application provides a positive electrode plate and a processing method thereof, a battery and an electrical device, which are helpful to improve the burr problem at the edge of the positive electrode plate.

[0004] The embodiment of the present application is implemented as follows:

[0005] In a first aspect, an embodiment of the present application provides a method for processing a positive electrode plate, comprising: performing a combustion treatment on a designated portion of the positive electrode plate, wherein the designated portion includes at least a portion of the surface of a positive active material layer of the positive electrode plate.

[0006] The processing method of the positive electrode plate provided in the embodiment of the present application performs combustion treatment on the surface of the positive electrode plate. The flame can ablate and reduce the floating binder, which is beneficial to improve the blockage of the pores by the floating binder, thereby effectively improving the electrolyte wetting performance of the positive electrode plate.

[0007] In some embodiments, when the combustion process is completed, the burned area on the surface of the positive electrode active material layer reaches a specified temperature, and the specified temperature is 200°C to 500°C.

[0008] In these embodiments, the burned area on the surface of the positive electrode active material layer is controlled to reach a specified temperature when the combustion treatment is completed, so that the surface of the positive electrode active material layer can be burned at a suitable temperature, which is conducive to better ablation and reduction of floating binder, and can better improve the electrolyte wetting performance of the positive electrode plate.

[0009] It should be noted that, in other embodiments of the present application, the specified temperature may be, for example, 130°C to 500°C, 140°C to 500°C, 150°C to 500°C, or 160°C to 500°C.

[0010] In some embodiments, the designated temperature is 300°C to 500°C; alternatively, the designated temperature is 350°C to 470°C.

[0011] In these embodiments, the temperature is controlled to meet further specified conditions so that the surface of the positive electrode active material layer can be burned at a more suitable temperature, which is conducive to better ablation and reduction of floating binder, and can better improve the electrolyte wetting performance of the positive electrode plate.

[0012] In some embodiments, the binder in the positive electrode active material layer includes polyvinylidene fluoride.

[0013] In these embodiments, the combustion treatment can effectively remove the floating binder formed by polyvinylidene fluoride, and can effectively improve the electrolyte wetting performance of the positive electrode plate.

[0014] In some embodiments, the positive active material in the positive active material layer includes a lithium-containing phosphate.

[0015] In these embodiments, the decomposition temperatures of the lithium-containing phosphate and the binder have a large temperature difference, which facilitates the regulation of the specified temperature above the decomposition temperature of the binder and below the decomposition temperature of the lithium-containing phosphate. This allows the positive electrode active material layer to maintain good electrochemical properties while effectively removing the floating binder and improving the wetting performance.

[0016] In some embodiments, the lithium-containing phosphate includes lithium iron phosphate.

[0017] In these embodiments, the decomposition temperatures of lithium iron phosphate and the binder have a large temperature difference, which can effectively remove the floating binder to improve the wetting performance while allowing the positive electrode active material layer to maintain good electrochemical properties; at the same time, lithium iron phosphate is a commonly used positive electrode active material, and positive electrode plates using lithium iron phosphate often have the problem of poor wetting performance.

[0018] In some embodiments, the combustion treatment includes burning fuel gas and treating the designated area through flame.

[0019] In these embodiments, combustion treatment is performed by burning fuel gas, and the airflow generated by the fuel gas can blow away the ablation products of the floating binder, which is beneficial for the flame to more fully ablate the floating binder, and is also beneficial for maintaining a good cleanliness on the surface of the positive electrode plate.

[0020] In some embodiments, during the combustion process, the flow rate of the gas is 3 L / min to 12 L / min; optionally, the flow rate of the gas is 5 L / min to 8 L / min.

[0021] In these embodiments, a suitable gas flow rate is maintained during the combustion process so that the flame can provide suitable heat to a designated location and the floating binder can be effectively removed at a suitable temperature to improve the wetting performance.

[0022] In some embodiments, during the combustion process, the air flow rate is 70 L / min to 260 L / min; optionally, the air flow rate is 120 L / min to 180 L / min.

[0023] In these embodiments, maintaining a suitable air flow rate during the combustion process is beneficial to satisfying a suitable air-fuel ratio, so that the flame can provide suitable heat to the designated location and can effectively remove the floating binder at a suitable temperature to improve the wetting performance.

[0024] In some embodiments, during the combustion process, the air-fuel ratio is (2-5):1; optionally, the air-fuel ratio is (3-4):1.

[0025] In these embodiments, a suitable air-fuel ratio is satisfied during the combustion process so that the flame can provide suitable heat to a designated location and the floating binder can be effectively removed at a suitable temperature to improve the wetting performance.

[0026] In some embodiments, during the combustion process, fuel gas is sprayed toward the positive electrode plate at a specified distance from the positive electrode plate for combustion, and the specified distance is 5 cm to 10 cm; optionally, the specified distance is 5 cm to 7.5 cm.

[0027] In these embodiments, the combustion of fuel gas is sprayed toward the positive electrode plate at a suitable designated distance, which is beneficial to regulating the temperature of the flame acting on the positive electrode plate, and can better remove the floating binder to improve the wetting performance.

[0028] In some embodiments, during the combustion process, fuel gas is sprayed toward the positive electrode plate in a specified direction for combustion, and the angle between the specified direction and the thickness direction of the positive electrode plate is 0° to 30°; optionally, the angle between the specified direction and the thickness direction of the positive electrode plate is 0° to 10°.

[0029] In these embodiments, the fuel gas is sprayed toward the positive electrode plate at a suitable designated angle for combustion, so that the flame can better burn the positive electrode plate and can more effectively remove the floating binder to improve the wetting performance.

[0030] In some embodiments, during the combustion process, the positive electrode plate passes through the flame at a specified speed, and the specified speed is 40m / min to 100m / min; optionally, the specified speed is 50m / min to 80m / min.

[0031] In these embodiments, passing the positive electrode sheet through the flame at a suitable specified speed is helpful to control the surface of the positive electrode sheet to reach a suitable temperature, and can better remove the floating binder to improve the wetting performance.

[0032] In a second aspect, an embodiment of the present application provides a positive electrode sheet, which is obtained by processing according to the processing method of the positive electrode sheet of the above embodiment.

[0033] In some embodiments, the wetting rate of the positive electrode plate to the electrolyte is greater than 0.27 μg / s. Optionally, the wetting rate of the positive electrode plate to the electrolyte is greater than or equal to 0.33 μg / s.

[0034] In these embodiments, the positive electrode plate has a higher wetting speed to the electrolyte, and the positive electrode plate has better electrolyte wetting performance.

[0035] In some embodiments, the porosity of the positive electrode sheet is greater than 29.2%; optionally, the porosity of the positive electrode sheet is greater than or equal to 32.6%.

[0036] In these embodiments, the positive electrode plate has a higher porosity, which is beneficial to improving the electrolyte wetting performance of the positive electrode plate.

[0037] In a third aspect, an embodiment of the present application provides a battery, comprising a positive electrode plate as described in the above embodiment.

[0038] In a fourth aspect, an embodiment of the present application provides an electrical device, comprising a battery as described in the above embodiment.

[0039] The above description is only an overview of the technical solution of the embodiment 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

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0041] Figure 1 A schematic diagram of the structure of a vehicle provided in some embodiments of the present application;

[0042] Figure 2 An exploded view of a battery provided for some embodiments of the present application;

[0043] Figure 3 An exploded view of a battery cell provided for some embodiments of the present application;

[0044] Figure 4 A schematic diagram of the structure of an electrode assembly provided in some embodiments of the present application;

[0045] Figure 5 A process flow chart of a method for processing a positive electrode sheet provided in some embodiments of the present application;

[0046] Figure 6 A schematic diagram of a method for processing a positive electrode sheet provided in some embodiments of the present application in a side view;

[0047] Figure 7 A schematic diagram of a method for processing a positive electrode plate provided in some embodiments of the present application from a top view.

[0048] icon:

[0049] 1000-Vehicles;

[0050] 100-battery; 200-controller; 300-motor;

[0051] 10-box; 11-first part; 12-second part; 13-accommodating space;

[0052] 20-battery cell; 21-housing; 22-electrode assembly; 23-electrode terminal; 24-pressure relief structure;

[0053] 211-housing; 212-cover; 213-sealed space;

[0054] 221-positive electrode plate; 222-negative electrode plate; 223-separating film;

[0055] 2221 - a first surface of the positive electrode active material layer; 2222 - a second surface of the positive electrode active material layer;

[0056] A-thickness direction of the positive electrode sheet; B-specified direction; C-passing direction of the positive electrode sheet; D-gas delivery and ignition device; L-specified distance. DETAILED DESCRIPTION

[0057] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0058] 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.

[0059] 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.

[0060] In the description of the embodiments of the present application, technical terms such as "first" and "second" 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.

[0061] In the description of the embodiments of the present application, the technical term "and / or", such as "Feature 1 and / or Feature 2", means that it can be "Feature 1" alone, it can be "Feature 2" alone, or it can be "Feature 1" plus "Feature 2". In addition, the character " / " in this article generally indicates that the objects before and after are in an "or" relationship.

[0062] In the description of the embodiments of the present application, unless otherwise specified, the meaning of “multiple” in “one or more” is two or more than two.

[0063] 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.

[0064] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the heights, lengths, widths, and other dimensions of the various components in the embodiments of the present application shown in the drawings, as well as the overall heights, lengths, widths, and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0065] From the perspective of market development, the application of power batteries is becoming more and more extensive. Power batteries 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 power batteries, the market demand is also constantly expanding.

[0066] With the continuous development of the new energy industry, the market has put forward more diversified demands on battery electrodes. The electrolyte wetting performance of the positive electrode is a factor that affects battery performance. Improving the electrolyte wetting performance of the positive electrode is conducive to improving the battery's rate performance, discharge capacity, etc.

[0067] As the requirements for the thickness of the positive electrode active material layer become higher and higher, the compaction density of the positive electrode sheet becomes higher and higher, and the pores between the active materials are compressed smaller and smaller, making it difficult for the electrolyte to infiltrate therein. In some current technical solutions, in order to improve the wetting performance, the positive electrode sheet is usually improved based on the above reasons.

[0068] However, studies have found that the floating of binder and the clogging of pores are an important reason affecting the electrolyte's ability to wet the positive electrode sheet, and the current technical solutions cannot effectively remove the floating binder in the positive electrode sheet.

[0069] Based on this, an embodiment of the present application proposes a positive electrode plate and a processing method thereof, in which the surface of the positive electrode plate is subjected to combustion treatment. The flame can ablate and reduce the floating binder, which is beneficial to improving the blockage of the pores by the floating binder, thereby effectively improving the electrolyte wetting performance of the positive electrode plate.

[0070] The battery cell using the positive electrode sheet disclosed in the embodiment of the present application can be used in, but not limited to, electrical devices such as vehicles, ships or aircraft. The embodiment of the present application provides an electrical device using a battery as a power source, and the electrical device can be, but not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, and the like. Among them, the electric toy can include fixed or mobile electric toys, for example, game consoles, electric car toys, electric ship toys, and electric airplane toys, and the like, and the spacecraft can include airplanes, rockets, space shuttles, and spacecrafts, and the like.

[0071] For the convenience of explanation, the following embodiments are described by taking a vehicle as an example of an electrical device in an embodiment of the present application.

[0072] See also Figure 1 , Figure 1A schematic diagram of the structure of a vehicle 1000 provided for some embodiments of the present application. The vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000, and the battery 100 may be provided at the bottom, head or tail of the vehicle 1000. The battery 100 may be used to power the vehicle 1000, for example, the battery 100 may be used as an operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300, and the controller 200 is used to control the battery 100 to power the motor 300, for example, for starting, navigating and driving the vehicle 1000.

[0073] In some embodiments of the present application, the battery 100 can not only serve as an operating power source for the vehicle 1000, but also serve as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0074] In the present application, the battery 100 refers to a single physical module including one or more battery cells 20 to provide a certain voltage and capacity, which may be in the form of a battery pack, a battery module, etc. The battery 100 may include a box 10 for encapsulating one or more battery cells 20, and the box 10 may prevent liquid or other foreign matter from affecting the charging or discharging of the battery cells 20.

[0075] See also Figure 2 , Figure 2 An exploded view of a battery 100 provided for some embodiments of the present application. The battery 100 includes a box 10 and a plurality of battery cells 20, and the plurality of battery cells 20 are accommodated in the box 10. Among them, the box 10 is used to accommodate the battery cells 20, and the box 10 can be a variety of structures. In some embodiments, the box 10 can include a first part 11 and a second part 12, the first part 11 and the second part 12 cover each other, and the first part 11 and the second part 12 jointly define a receiving space 13 for accommodating the battery cells 20. The second part 12 can be a hollow structure with one end open, the first part 11 is a plate-like structure, and the first part 11 covers the open side of the second part 12 to form a box 10 with a receiving space 13; the first part 11 and the second part 12 can also be hollow structures with one side open, and the open side of the first part 11 covers the open side of the second part 12 to form a box 10 with a receiving space 13. Of course, the first part 11 and the second part 12 can be a variety of shapes, such as a cylinder, a cuboid, etc.

[0076] In the battery 100, multiple battery cells 20 can be connected in series, in parallel, or in a hybrid connection. A hybrid connection means that multiple battery cells 20 are both connected in series and in parallel. Multiple battery cells 20 can be directly connected in series, in parallel, or in a hybrid connection, and then the whole formed by multiple battery cells 20 is accommodated in the box 10. Alternatively, multiple battery cells 20 can be connected in series, in parallel, or in a hybrid connection to form a module, and multiple modules can be connected in series, in parallel, or in a hybrid connection to form a whole, and then accommodated in the box 10. The battery 100 can also include other structures. For example, multiple battery cells 20 can be electrically connected through a busbar component to achieve parallel, series, or hybrid connection of multiple battery cells 20.

[0077] The battery cell 20 refers to the smallest unit constituting the battery pack and can be a lithium-sulfur battery, a sodium-ion battery or a magnesium-ion battery, but is not limited thereto.

[0078] See also Figure 3 The battery cell 20 may include a housing 21 , an electrode assembly 22 and an electrolyte, and both the electrode assembly 22 and the electrolyte are contained in the housing 21 .

[0079] The housing 21 may include a shell 211 and a cover 212. The shell 211 is a component used to cooperate with the cover 212 to form an internal sealed space 213 of the battery cell 20, wherein the formed sealed space 213 can be used to accommodate the electrode assembly 22, electrolyte and other components. The cover 212 refers to a component that covers the opening of the shell 211 to isolate the internal environment of the battery cell 20 from the external environment. The shape of the cover 212 can be adapted to the shape of the shell 211 to cooperate with the shell 211, and the cover 212 may also be provided with functional components such as electrode terminals 23 and pressure relief structures 24. A sealing ring may be configured between the opening of the shell 211 and the cover 212 to achieve sealing between the shell 211 and the cover 212.

[0080] The shell 211 and the cover 212 can be of various shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism, etc. Specifically, the shapes of the shell 211 and the cover 212 can be determined according to the specific shape and size of the electrode assembly 22. The shell 211 and the cover 212 can be made of various materials, such as but not limited to metals such as copper, iron, aluminum, stainless steel, and aluminum alloy. The sealing ring can be made of various materials, such as but not limited to PP (polypropylene), PC (polycarbonate), PET (polyethylene terephthalate) and other materials that are resistant to electrolyte corrosion, high toughness and fatigue resistance. A coating can be formed on the outer surface of the shell 211, and the material of the coating can be various, such as but not limited to corrosion-resistant materials such as Ni and Cr.

[0081] The battery cell 20 may also be in a soft pack form, such as a bag-type soft pack. The material of the soft pack may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0082] See also Figure 4 , the electrode assembly 22 includes a negative electrode sheet 222, a separator 223 and a positive electrode sheet 221. The battery cell 20 mainly relies on the movement of metal ions between the positive electrode sheet 221 and the negative electrode sheet 222 to work. During the charging and discharging process, the active ions are embedded and removed back and forth between the positive electrode sheet 221 and the negative electrode sheet 222; the separator 223 is arranged between the positive electrode sheet 221 and the negative electrode sheet 222, which mainly plays a role in preventing the positive and negative electrodes from short-circuiting, and at the same time allows ions to pass through. The electrode assembly 22 can be a winding structure or a stacked structure, and the embodiments of the present application are not limited to this.

[0083] The positive electrode sheet 221 includes a positive electrode current collector and a positive electrode active material layer. The positive electrode active material layer is disposed on at least one side of the positive electrode current collector. A primer layer or the like may be disposed between the positive electrode active material layer and the positive electrode current collector.

[0084] Among them, the positive electrode current collector can be a metal foil or a composite current collector, for example, the material of the positive electrode current collector can be aluminum. The composite current collector can include a polymer material substrate and a metal layer formed on at least one side of the polymer material substrate, and the composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0085] The positive electrode active material in the positive electrode active material layer may include at least one of the following materials: lithium-containing phosphates with an olivine structure, lithium transition metal oxides, and their respective modified compounds. However, the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials may also be used. These positive electrode active materials may be used alone or in combination of two or more. Examples of lithium transition metal oxides may include, but are not limited to, lithium cobalt oxides (such as LiCoO 2 ), lithium nickel oxide (such as LiNiO 2 ), lithium manganese oxide (such as LiMnO 2 、LiMn 2 O 4 ), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O 2(Also referred to as NCM 333 )、LiNi 0.5 Co 0.2 Mn 0.3 O 2 (Also referred to as NCM 523 )、LiNi 0.5 Co 0.25 Mn 0.25 O 2 (Also referred to as NCM 211 )、LiNi 0.6 Co 0.2 Mn 0.2 O 2 (Also referred to as NCM 622 )、LiNi 0.8 Co 0.1 Mn 0.1 O 2 (Also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O 2 ) and its modified compounds, etc. Examples of lithium phosphates containing olivine structures may include, but are not limited to, lithium iron phosphate (such as LiFePO 4 ), composite materials of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), at least one of a composite material of lithium manganese phosphate and carbon, a composite material of lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon.

[0086] In some embodiments, the positive electrode active material layer may further include a binder. As an example, the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylate resin.

[0087] In some embodiments, the positive electrode active material layer may further include a conductive agent. As an example, the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0088] The negative electrode sheet 222 includes a negative electrode current collector and a negative electrode active material layer. The negative electrode active material layer is disposed on at least one side of the negative electrode current collector. A primer layer or the like may be disposed between the negative electrode current collector and the negative electrode active material layer.

[0089] Among them, the negative electrode current collector can be a metal foil or a composite current collector. For example, the material of the negative electrode current collector can be copper. The composite current collector may include a polymer material substrate and a metal layer formed on at least one side of the polymer material substrate. The composite current collector can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0090] The negative electrode active material in the negative electrode active material layer may be a negative electrode active material such as carbon and silicon. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active material materials may also be used.

[0091] In some embodiments, the negative electrode active material layer may further include a binder. The binder may be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA) and carboxymethyl chitosan (CMCS).

[0092] In some embodiments, the negative electrode active material layer may further include a conductive agent, which may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0093] In some embodiments, the negative electrode active material layer may further include other additives, such as a thickener (eg, sodium carboxymethyl cellulose (CMC-Na)).

[0094] The isolation membrane 223 is located between the positive electrode plate 221 and the negative electrode plate 222 to serve as an isolation. The embodiment of the present application has no particular restriction on the type of the isolation membrane 223, and any known porous structure isolation membrane 223 with good chemical stability and mechanical stability can be selected.

[0095] In some embodiments, the material of the isolation film 223 can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride. The isolation film 223 can be a single-layer film or a multi-layer composite film, without particular limitation. When the isolation film 223 is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.

[0096] Next, the positive electrode plate 221 and the processing method thereof proposed in the embodiment of the present application are described in detail.

[0097] See also Figure 5 In a first aspect, an embodiment of the present application provides a method for processing a positive electrode plate, comprising: performing a combustion treatment on a designated portion of the positive electrode plate 221 , wherein the designated portion includes at least a portion of the surface of the positive active material layer of the positive electrode plate 221 .

[0098] See also Figure 6 The surface of the positive electrode active material layer includes a first surface 2221 of the positive electrode active material layer and a second surface 2222 of the positive electrode active material layer. The first surface 2221 of the positive electrode active material layer refers to a surface of the positive electrode active material layer distributed along the thickness direction A of the positive electrode sheet. In other words, the first surface of the positive electrode active material layer is substantially perpendicular to the thickness direction A of the positive electrode sheet; the second surface 2222 of the positive electrode active material layer refers to a surface of the positive electrode active material layer substantially parallel to the thickness direction A of the positive electrode sheet.

[0099] As an example, the designated portion includes at least the first surface 2221 of the positive electrode active material layer.

[0100] The processing method of the positive electrode plate provided in the embodiment of the present application performs combustion treatment on the surface of the positive electrode plate 221. The flame can ablate and reduce the floating binder, which is beneficial to improve the clogging of the pores by the floating binder, and can increase the porosity of the positive electrode active material layer, thereby effectively improving the electrolyte wetting performance of the positive electrode plate 221.

[0101] In addition, the study found that although the combustion process consumes the binder in the positive electrode active material layer, since it consumes the floating binder, the positive electrode active material layer and the positive electrode current collector can maintain good adhesion. It is also found that despite the combustion process, the resistance of the positive electrode sheet 221 is reduced, which is beneficial to improving the electrical performance of the positive electrode sheet 221.

[0102] In some embodiments, when the combustion process is completed, the burned area on the surface of the positive electrode active material layer reaches a specified temperature, and the specified temperature is 200°C to 500°C.

[0103] As an example, the designated temperature is, for example but not limited to, any one of 200° C., 250° C., 300° C., 350° C., 400° C., 450° C. or 500° C., or a range of values ​​between any two thereof.

[0104] When the combustion process is completed, it means after the combustion process is completed and before the cooling process; for example, it means when the burned area passes through the flame area, the detection is performed within a certain distance downstream of the flame area, and the certain distance is, for example, 5cm to 20cm.

[0105] The specified temperature can be measured by a temperature measuring device such as an infrared temperature gun when the combustion process is completed.

[0106] In these embodiments, the burned area on the surface of the positive electrode active material layer is controlled to reach a specified temperature when the burning treatment is completed, so that the surface of the positive electrode active material layer can be burned at a suitable temperature, which is conducive to better ablation and reduction of floating binder, and can better improve the electrolyte wetting performance of the positive electrode plate 221.

[0107] In some embodiments, the designated temperature is 300°C to 500°C; alternatively, the designated temperature is 350°C to 470°C.

[0108] In these embodiments, the control is to meet further specified temperatures so that the surface of the positive electrode active material layer can be burned at a more suitable temperature, which is conducive to better ablation and reduction of floating binder, and can better improve the electrolyte wetting performance of the positive electrode plate 221.

[0109] In some embodiments, the binder in the positive electrode active material layer includes polyvinylidene fluoride.

[0110] As an example, the binder in the positive electrode active material layer is mainly polyvinylidene fluoride, for example, the binder is polyvinylidene fluoride.

[0111] Polyvinylidene fluoride, abbreviated as PVDF; the decomposition temperature is relatively low, about 280℃~350℃.

[0112] In these embodiments, the combustion treatment can effectively remove the floating binder formed by polyvinylidene fluoride, and can effectively improve the electrolyte wetting performance of the positive electrode plate 221.

[0113] In some embodiments, the positive active material in the positive active material layer includes a lithium-containing phosphate.

[0114] As an example, the positive electrode active material in the positive electrode active material layer is mainly lithium-containing phosphate, for example, the positive electrode active material is lithium-containing phosphate.

[0115] Among them, lithium phosphates include Li 1+y1 Fey2 Mn y3 M y4 P 1-y5 O 4-y6 , wherein, -0.8≤y1≤0.2, 0≤y2≤1, 0≤y3≤1, 0≤y4≤0.1, 0≤y5≤0.1, 0≤y6≤0.4, and M includes one or more of Al, Cu, Mg, Zn, Ni, Ti, V, Zr, Co, Ga, Sn, Sb, Nb or Ge.

[0116] In these embodiments, the decomposition temperatures of the lithium-containing phosphate and the binder have a large temperature difference, which facilitates the regulation of the specified temperature above the decomposition temperature of the binder and below the decomposition temperature of the lithium-containing phosphate. This allows the positive electrode active material layer to maintain good electrochemical properties while effectively removing the floating binder and improving the wetting performance.

[0117] In some embodiments, the lithium-containing phosphate includes lithium iron phosphate.

[0118] As an example, the lithium-containing phosphate is mainly lithium iron phosphate, for example, the lithium-containing phosphate is lithium iron phosphate.

[0119] Among them, lithium iron phosphate includes Li 1+y1 Fe y2 P 1-y5 O 4-y6 ; The values ​​of y1, y5 and y6 refer to the above, 0<y2≤1; The lithium iron phosphate is, for example, LiFePO 4 , abbreviated as LFP, the decomposition temperature is about 550℃~750℃.

[0120] In these embodiments, the decomposition temperatures of lithium iron phosphate and the binder have a large temperature difference, which can effectively remove the floating binder to improve the wetting performance while allowing the positive electrode active material layer to maintain good electrochemical properties; at the same time, lithium iron phosphate is a commonly used positive electrode active material, and the positive electrode sheets using lithium iron phosphate have an increasing compaction density, and the gaps between the positive electrode active materials are compressed smaller and smaller, resulting in frequent problems with poor wetting performance.

[0121] In some embodiments, the combustion treatment includes burning fuel gas and treating the designated area through flame.

[0122] The fuel gas includes combustible gas, which is introduced into a designated position of the combustion process for combustion through a gas delivery and ignition device D such as a spray gun or a burner. In the process of delivering the fuel gas, an auxiliary fuel gas may be optionally delivered together with the fuel gas or separately from the fuel gas.

[0123] In the process of treating the designated part by the generated flame, the flame heats the designated part so that the designated part is burned by the flame.

[0124] Optionally, the fuel gas includes one or more of methane, propane or acetylene.

[0125] As an example, the fuel gas may be one of methane, propane and acetylene.

[0126] As another example, the fuel gas includes a variety of combustible gases, one or more of which are selected from methane, propane or acetylene, and may also include other types of combustible gases, for example, the fuel gas is liquefied gas, coal gas or natural gas.

[0127] In these embodiments, combustion treatment is performed by burning fuel gas, and the airflow generated by the fuel gas can blow away the ablation products of the floating binder, which is beneficial for the flame to more fully ablate the floating binder, and is also beneficial for maintaining a good cleanliness on the surface of the positive electrode plate 221.

[0128] In some embodiments, during the combustion process, the flow rate of the gas is 3 L / min to 12 L / min; optionally, the flow rate of the gas is 5 L / min to 8 L / min.

[0129] The flow rate of a specified gas refers to the volume of the specified gas supplied per unit time.

[0130] As an example, the flow rate of the gas is, for example but not limited to, any one of 3L / min, 4L / min, 5L / min, 6L / min, 7L / min, 8L / min, 9L / min, 10L / min, 11L / min or 12L / min, or a range between any two of them.

[0131] In these embodiments, a suitable gas flow rate is maintained during the combustion process so that the flame can provide suitable heat to a designated location and the floating binder can be effectively removed at a suitable temperature to improve the wetting performance.

[0132] In some embodiments, during the combustion process, the air flow rate is 70 L / min to 260 L / min; optionally, the air flow rate is 120 L / min to 180 L / min.

[0133] As an example, the air flow rate is, for example but not limited to, any one of 70 L / min, 80 L / min, 90 L / min, 100 L / min, 110 L / min, 120 L / min, 130 L / min, 140 L / min, 150 L / min, 160 L / min, 170 L / min, 180 L / min, 190 L / min, 200 L / min, 210 L / min, 220 L / min, 230 L / min, 240 L / min, 250 L / min or 260 L / min, or a range between any two of them.

[0134] In these embodiments, maintaining a suitable air flow rate during the combustion process is beneficial to satisfying a suitable air-fuel ratio, so that the flame can provide suitable heat to the designated location and can effectively remove the floating binder at a suitable temperature to improve the wetting performance.

[0135] In some embodiments, during the combustion process, the air-fuel ratio is (2-5):1; optionally, the air-fuel ratio is (3-4):1.

[0136] As an example, the air-fuel ratio is, for example but not limited to, any one of 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1 or 5:1, or a range of values ​​between any two of them.

[0137] The air-fuel ratio is common knowledge in the art, has a well-known meaning in the art, and can be measured by instruments and testing methods known in the art. As an example, the air-fuel ratio refers to the mass ratio between air and gas, and can be regulated by a flow design method for matching gas and air. As an example, according to the air-fuel ratio requirement, gas and air are mixed at a specific flow rate, and then the mixed gas is introduced for combustion.

[0138] In these embodiments, a suitable air-fuel ratio is satisfied during the combustion process so that the flame can provide suitable heat to a designated location and the floating binder can be effectively removed at a suitable temperature to improve the wetting performance.

[0139] See also Figure 6 In some embodiments, during the combustion process, fuel gas is sprayed toward the positive electrode plate 221 at a specified distance L from the positive electrode plate 221 for combustion, and the specified distance L is 5 cm to 10 cm; optionally, the specified distance L is 5 cm to 7.5 cm.

[0140] As an example, the specified distance L is, for example but not limited to, any one of 5 cm, 6 cm, 7 cm, 8 cm, 9 cm, or 10 cm, or a range of values ​​between any two of them.

[0141] See also Figure 6The specified distance L refers to the vertical distance from the gas combustion port to the first surface 2221 of the positive electrode plate, that is, the distance from the gas combustion port to the first surface 2221 of the positive electrode plate along the thickness direction A of the positive electrode plate.

[0142] In these embodiments, the combustion of fuel gas is sprayed toward the positive electrode plate 221 at a suitable designated distance, which is beneficial to regulating the temperature of the flame acting on the positive electrode plate 221 and can better remove the floating binder to improve the wetting performance.

[0143] See also Figure 6 In some embodiments, during the combustion process, fuel gas is sprayed toward the positive electrode plate 221 in a specified direction B for combustion, and the angle between the specified direction B and the thickness direction A of the positive electrode plate is 0° to 30°; optionally, the angle between the specified direction B and the thickness direction A of the positive electrode plate is 0° to 10°.

[0144] As an example, as an example, the angle between the specified direction B and the thickness direction A of the positive electrode sheet is, for example but not limited to, any point value of 0°, 5°, 10°, 15°, 20°, 25° or 30°, or a range value between any two of them.

[0145] When the angle between the specified direction B and the thickness direction A of the positive electrode sheet is 0°, the specified direction B is basically perpendicular to the first surface 2221 of the positive electrode active material layer; when the angle between the specified direction B and the thickness direction A of the positive electrode sheet is 90°, the specified direction B is basically parallel to the first surface 2221 of the positive electrode active material layer.

[0146] See also Figure 6 The designated direction B refers to the direction in which the gas is ejected from the burner port, and the designated direction B is substantially consistent with the axial direction of the burner port.

[0147] In these embodiments, the fuel gas is sprayed toward the positive electrode plate 221 at a suitable designated angle for combustion, so that the flame can better burn the positive electrode plate 221 and can more effectively remove the floating binder to improve the wetting performance.

[0148] In some embodiments, during the combustion process, the positive electrode plate 221 passes through the flame at a specified speed, and the specified speed is 40m / min to 100m / min; optionally, the specified speed is 50m / min to 80m / min.

[0149] As an example, the specified speed is, for example but not limited to, any one of 40 m / min, 50 m / min, 60 m / min, 70 m / min, 80 m / min, 90 m / min or 100 m / min, or a range of values ​​between any two of them.

[0150] See also Figure 6 and Figure 7 In an embodiment of the present application, optionally, the position of the gas conveying and ignition device D for injecting the ignition fuel gas is kept fixed, and the positive electrode plate 221 is conveyed at a specified speed relative to the gas conveying and ignition device D by means of a belt, roller, etc., so that the positive electrode plate 221 passes through the flame at a specified speed.

[0151] As an example, the first surface 2221 of the positive electrode active material layer is placed flat on the conveying surface for conveying, that is, the passing direction C of the positive electrode sheet is substantially perpendicular to the thickness direction A of the positive electrode sheet.

[0152] In these embodiments, passing the positive electrode plate 221 through the flame at a suitable specified speed is helpful to control the surface of the positive electrode plate 221 to reach a suitable temperature, and can better remove the floating binder to improve the wetting performance.

[0153] In some exemplary embodiments, the positive electrode sheet 221 includes a first edge relatively distributed along a first direction and a second edge relatively distributed along a second direction; exemplarily, the first direction and the second direction are two directions perpendicular to each other. During the combustion treatment, the positive electrode sheet 221 passes through the flame along the second direction, and the flame can at least cover the entire range of the first surface 2221 of the positive active material layer in the first direction (that is, it can cover from one side edge in the first direction to the other side edge opposite thereto), so that after the entire positive electrode sheet 221 passes through the flame along the second direction mentioned above, the first surface 2221 of the entire positive active material layer facing the flame is subjected to the combustion treatment.

[0154] In a second aspect, an embodiment of the present application provides a positive electrode sheet 221 , which is obtained by processing according to the positive electrode sheet processing method of the above embodiment.

[0155] In some embodiments, the wetting rate of the positive electrode plate 221 to the electrolyte is greater than 0.27 μg / s. Optionally, the wetting rate of the positive electrode plate 221 to the electrolyte is greater than or equal to 0.33 μg / s.

[0156] In these embodiments, the positive electrode plate 221 has a higher wetting speed to the electrolyte, and the positive electrode plate 221 has better electrolyte wetting performance.

[0157] In some embodiments, the porosity of the positive electrode plate 221 is greater than 29.2%; optionally, the porosity of the positive electrode plate 221 is greater than or equal to 32.6%.

[0158] In these embodiments, the positive electrode plate 221 has a higher porosity, which is beneficial to improving the electrolyte wetting performance of the positive electrode plate 221.

[0159] In a third aspect, an embodiment of the present application provides a battery 100, comprising a positive electrode plate 221 as described in the above embodiment.

[0160] In a fourth aspect, an embodiment of the present application provides an electrical device, comprising a battery 100 as described in the above embodiment.

[0161] Some specific embodiments are listed below to better illustrate the present application.

[0162] 1. Processing of the positive electrode

[0163] (1) Preparation of positive electrode sheet

[0164] Lithium iron phosphate (LFP), conductive agent carbon black, polyvinylidene fluoride (PVDF), and N-methylpyrrolidone (NMP) are stirred and mixed evenly in a weight ratio of 97:2:1:21 to obtain a positive electrode slurry; then the positive electrode slurry is evenly coated on the positive electrode collector, and then dried, cold pressed, and cut to obtain a positive electrode sheet.

[0165] (2) Surface treatment of positive electrode

[0166] The positive electrode sheet is placed in a transmission device, the fuel gas is ignited, and the positive electrode sheet is passed through the flame through the transmission device, so that the first surface of the entire active material layer facing the flame is treated by the flame.

[0167] Among them, the placement direction of the positive electrode sheet, the passing direction of the positive electrode sheet, the configuration position of the gas delivery and ignition device, etc. Figure 6 and Figure 7 As shown; the process parameter conditions such as gas flow rate, air flow rate, air-fuel ratio, the angle between the specified direction and the thickness direction of the positive electrode sheet, the specified distance, the specified speed, etc. are shown in Table 1.

[0168] Table 1. Process parameters and conditions

[0169]

[0170]

[0171] In Table 1, Comparative Example 1 indicates that the positive electrode plate was not subjected to combustion treatment.

[0172] In addition, it should be noted that since the composition of the gas and air used in different embodiments may be slightly different, the difference in the flow ratio of gas to air and the difference in the air-fuel ratio between different embodiments are not necessarily 1:1 related. For example, the flow ratio of gas to air is different between Embodiment 1 and Embodiment 2, but the air-fuel ratio of the two is the same.

[0173] 2. Test Method

[0174] (1) Specified temperature detection

[0175] When the positive electrode piece passes through the flame area, an infrared temperature measuring gun is used to detect the surface temperature of the positive electrode piece at a distance of 8 cm downstream of the flame area to obtain the specified temperature.

[0176] (2) Electrolyte wetting performance test

[0177] Fix the positive electrode plate on a clean glass plate; use a 0.2mm capillary to absorb electrolyte at a height of 3mm and then make vertical contact with the positive electrode plate to allow the positive electrode plate to absorb the electrolyte. Measure the time it takes to absorb the electrolyte and obtain the electrolyte absorption rate, i.e. the infiltration rate, by conversion.

[0178] (3) Porosity detection

[0179] In a drying room, use tweezers to select >20 discs with good appearance and no powder falling off the edges and put them into the sample cup. Record the number of discs and calculate the apparent volume. Place the sample cup with the sample in the true density tester, close the test system, and introduce helium according to the program. By detecting the pressure of the gas in the sample chamber and the expansion chamber, calculate the real volume according to Bohr's law (PV=nRT), and then obtain the porosity of the sample to be tested.

[0180] (4) Resistance detection

[0181] Cut small discs with a diameter of 10 mm on the left, middle and right sides of the positive electrode. Turn on the indicator light of the Yuanneng Technology electrode resistor meter, place the small disc in the appropriate position of the "probe" of the membrane resistor meter, click the "Start" button, and wait for the reading to stabilize before reading. Test two positions of each small disc, and finally calculate the average value of the six measurements, which is the membrane resistance of the positive electrode.

[0182] (5) Adhesion test

[0183] Cut the positive electrode into 20*100mm 2 The test specimens of different sizes are kept for later use; the double-sided tape is used to adhere the side of the specimen to be tested, and is compacted with a pressure roller to make the double-sided tape fit the specimen completely; the other side of the double-sided tape of the specimen is adhered to the stainless steel surface, and one end of the specimen is bent in the opposite direction with a bending angle of 180°; the high-speed rail tensile testing machine is used for testing, one end of the stainless steel is fixed to the fixture below the tensile testing machine, and the bent end of the specimen is fixed to the fixture above, the angle of the specimen is adjusted to ensure that the upper and lower ends are in a vertical position, and then the specimen is stretched at a speed of 50 mm / min until the specimen is completely peeled off from the substrate, and the displacement and force in the process are recorded. It is generally believed that the force when the force is balanced is the bonding force of the positive electrode sheet.

[0184] 3. Test results and analysis

[0185] The test results of the positive electrode are shown in Table 2.

[0186] Table 2

[0187]

[0188]

[0189] Combining Table 1 and Table 2, a brief analysis is as follows:

[0190] In Examples 1 to 21, the positive electrode sheet was subjected to a combustion treatment; in Comparative Example 1, the positive electrode sheet was not subjected to a combustion treatment. Compared with Comparative Example 1, the infiltration rate and porosity of the positive electrode sheet in Examples 1 to 21 were improved to varying degrees. Moreover, compared with Comparative Example 1, Examples 1 to 21 maintained good adhesion, and the membrane resistance not only did not deteriorate but also decreased to varying degrees.

[0191] In Examples 1 to 21, when the surface temperature of the electrode sheet reaches above 300° C., and further reaches above 350° C., the wetting rate and porosity of the positive electrode sheet can reach a good level.

[0192] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A method for processing a positive electrode sheet, characterized in that: include: A combustion treatment is performed on a designated portion of the positive electrode plate, wherein the designated portion includes at least a portion of a surface of a positive electrode active material layer of the positive electrode plate.

2. The method for processing a positive electrode sheet according to claim 1, characterized in that: When the combustion treatment is completed, the burned area on the surface of the positive electrode active material layer reaches a specified temperature, and the specified temperature is 200° C. to 500° C.

3. The method for processing a positive electrode sheet according to claim 2, characterized in that: The designated temperature is 300°C to 500°C; optionally, the designated temperature is 350°C to 470°C.

4. The method for processing a positive electrode sheet according to any one of claims 1 to 3, characterized in that: The binder in the positive electrode active material layer includes polyvinylidene fluoride.

5. The method for processing a positive electrode sheet according to any one of claims 1 to 4, characterized in that: The positive electrode active material in the positive electrode active material layer includes lithium-containing phosphate.

6. The method for processing a positive electrode sheet according to claim 5, characterized in that: The lithium-containing phosphate includes lithium iron phosphate.

7. The method for processing a positive electrode sheet according to any one of claims 1 to 6, characterized in that: The combustion treatment includes burning fuel gas and treating the designated part by flame.

8. The method for processing a positive electrode sheet according to claim 7, characterized in that: In the combustion process, the flow rate of the gas is 3L / min to 12L / min; optionally, the flow rate of the gas is 5L / min to 8L / min.

9. The method for processing a positive electrode sheet according to claim 7 or 8, characterized in that: In the combustion process, the air flow rate is 70L / min to 260L / min; optionally, the air flow rate is 120L / min to 180L / min.

10. The method for processing a positive electrode sheet according to any one of claims 7 to 9, characterized in that: In the combustion process, the air-fuel ratio is (2-5):1; optionally, the air-fuel ratio is (3-4):

1.

11. The method for processing a positive electrode sheet according to any one of claims 7 to 10, characterized in that: In the combustion process, the fuel gas is sprayed toward the positive electrode plate at a specified distance from the positive electrode plate for combustion, and the specified distance is 5 cm to 10 cm; optionally, the specified distance is 5 cm to 7.5 cm.

12. The method for processing a positive electrode sheet according to any one of claims 7 to 11, characterized in that: During the combustion process, the fuel gas is sprayed toward the positive electrode plate in a specified direction for combustion, and the angle between the specified direction and the thickness direction of the positive electrode plate is 0° to 30°; optionally, the angle between the specified direction and the thickness direction of the positive electrode plate is 0° to 10°.

13. The method for processing a positive electrode sheet according to any one of claims 7 to 12, characterized in that: During the combustion process, the positive electrode plate passes through the flame at a specified speed, and the specified speed is 40m / min to 100m / min; optionally, the specified speed is 50m / min to 80m / min.

14. A positive electrode sheet, characterized in that: The positive electrode sheet is obtained by processing according to any one of claims 1 to 13.

15. The positive electrode sheet according to claim 14, characterized in that: The wetting speed of the positive electrode plate to the electrolyte is greater than 0.27 μg / s. Optionally, the wetting speed of the positive electrode plate to the electrolyte is greater than or equal to 0.33 μg / s.

16. The positive electrode sheet according to claim 14 or 15, characterized in that: The porosity of the positive electrode sheet is greater than 29.2%; optionally, the porosity of the positive electrode sheet is greater than or equal to 32.6%.

17. A battery, characterized in that: It comprises the positive electrode sheet as claimed in any one of claims 14 to 16.

18. An electrical equipment, characterized in that: Comprising the battery of claim 17.

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