Positive electrode sheet and treatment method therefor, and battery and electric device

Abstract

A positive electrode sheet and a treatment method therefor, and a battery and an electric device. The treatment method for a positive electrode sheet comprises: performing a combustion treatment on a specified part of a positive electrode sheet, wherein the specified part comprises at least part of a surface of a positive electrode active material layer of the positive electrode sheet. In the treatment method for a positive electrode sheet, a combustion treatment is performed on a surface of the positive electrode sheet, enabling a floating binder to be ablated and reduced by means of flames, thus facilitating amelioration of a blockage of the floating binder in pores; thus, the electrolyte infiltration performance of the positive electrode sheet can be effectively improved.

Description

Positive electrode sheet and processing method thereof, battery and electrical equipment

[0001] Cross-references

[0002] This application claims priority to Chinese patent application No. 202310765774.2, filed on June 26, 2023, entitled “Positive electrode sheet and its processing method, battery and electrical equipment”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] 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

[0004] The electrolyte wetting properties of the positive electrode sheet are a factor that affects battery performance. Improving the electrolyte wetting properties of the positive electrode sheet can help improve the battery's rate capability and discharge capacity. However, to meet design requirements such as high energy density and high cycle stability, the wetting properties of current positive electrode sheets generally need to be improved.

[0005] Summary of the Invention

[0006] 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 conducive to improving the burr problem at the edge of the positive electrode plate.

[0007] The embodiment of the present application is implemented as follows:

[0008] 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 the positive active material layer of the positive electrode plate.

[0009] The processing method of the positive electrode plate provided in the embodiment of the present application performs a combustion treatment on the surface of the positive electrode plate. 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 infiltration performance of the positive electrode plate.

[0010] 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, which is 200° C. to 500° C.

[0011] 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.

[0012] It should be noted that, in other embodiments of the present application, the specified temperature may also be, for example, 130°C to 500°C, 140°C to 500°C, 150°C to 500°C, or 160°C to 500°C.

[0013] In some embodiments, the designated temperature is 300°C to 500°C; alternatively, the designated temperature is 350°C to 470°C.

[0014] 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 appropriate temperature, which is conducive to better ablation and reduction of floating binder, and can better improve the electrolyte wetting performance of the positive electrode sheet.

[0015] In some embodiments, the binder in the positive active material layer includes polyvinylidene fluoride.

[0016] 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 sheet.

[0017] In some embodiments, the positive active material in the positive active material layer includes a lithium-containing phosphate.

[0018] 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 can effectively remove the floating binder and improve the wetting performance while allowing the positive electrode active material layer to maintain good electrochemical properties.

[0019] In some embodiments, the lithium-containing phosphate includes lithium iron phosphate.

[0020] 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 and 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.

[0021] In some embodiments, the combustion treatment includes burning gas and treating the designated area with the flame.

[0022] 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 of the surface of the positive electrode plate.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] In these embodiments, maintaining a suitable air flow rate during the combustion process is conducive to meeting a suitable air-fuel ratio, so that the flame can provide suitable heat to the designated area and effectively remove the floating binder at a suitable temperature to improve the infiltration performance.

[0027] In some embodiments, during the combustion process, the air-fuel ratio is (2-5):1; optionally, the air-fuel ratio is (3-4):1.

[0028] 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.

[0029] In some embodiments, during the combustion process, fuel gas is sprayed toward the positive electrode sheet at a specified distance from the positive electrode sheet for combustion, and the specified distance is 5 cm to 10 cm; optionally, the specified distance is 5 cm to 7.5 cm.

[0030] In these embodiments, the combustion of fuel gas is injected toward the positive electrode plate at a suitable designated distance, which is beneficial for regulating the temperature of the flame acting on the positive electrode plate and can better remove the floating binder to improve the wetting performance.

[0031] In some embodiments, during the combustion process, gas is sprayed toward the positive electrode sheet in a specified direction for combustion, and the angle between the specified direction and the thickness direction of the positive electrode sheet is 0° to 30°; optionally, the angle between the specified direction and the thickness direction of the positive electrode sheet is 0° to 10°.

[0032] In these embodiments, the fuel gas is injected toward the positive electrode sheet at a suitable designated angle for combustion, so that the flame can better burn the positive electrode sheet and more effectively remove the floating binder to improve the wetting performance.

[0033] In some embodiments, during the combustion process, the positive electrode plate passes through the flame at a specified speed, which is 40 m / min to 100 m / min; optionally, the specified speed is 50 m / min to 80 m / min.

[0034] In these embodiments, passing the positive electrode sheet through the flame at a suitable specified speed is beneficial for controlling the surface of the positive electrode sheet to reach a suitable temperature, and can effectively remove the floating binder to improve the wetting performance.

[0035] In a second aspect, an embodiment of the present application provides a positive electrode sheet, which is obtained by processing according to the positive electrode sheet processing method of the above embodiment.

[0036] 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.

[0037] In these embodiments, the positive electrode plate has a higher wetting speed for the electrolyte, and the positive electrode plate has better electrolyte wetting performance.

[0038] 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%.

[0039] In these embodiments, the positive electrode sheet has a relatively high porosity, which is beneficial to improving the electrolyte infiltration performance of the positive electrode sheet.

[0040] In a third aspect, an embodiment of the present application provides a battery, comprising a positive electrode plate as described in the above embodiment.

[0041] In a fourth aspect, an embodiment of the present application provides an electrical device comprising a battery as described in the above embodiment.

[0042] The above description is only an overview of the technical solutions of the embodiments 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

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. 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 relevant drawings can be obtained based on these drawings without creative work.

[0044] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0045] FIG2 is an exploded view of a battery provided in some embodiments of the present application;

[0046] FIG3 is an exploded view of a battery cell provided in some embodiments of the present application;

[0047] FIG4 is a schematic structural diagram of an electrode assembly provided in some embodiments of the present application;

[0048] FIG5 is a process flow chart of a method for processing a positive electrode sheet according to some embodiments of the present application;

[0049] FIG6 is a schematic diagram of a side view of a method for processing a positive electrode sheet provided in some embodiments of the present application;

[0050] FIG7 is a schematic diagram of a top view of a method for processing a positive electrode sheet provided in some embodiments of the present application.

[0051] icon:

[0052] 1000-vehicles;

[0053] 100-battery; 200-controller; 300-motor;

[0054] 10-box; 11-first part; 12-second part; 13-accommodation space;

[0055] 20 - battery cell; 21 - housing; 22 - electrode assembly; 23 - electrode terminal; 24 - pressure relief structure;

[0056] 211-housing; 212-cover; 213-sealed space;

[0057] 221-positive electrode sheet; 222-negative electrode sheet; 223-separator;

[0058] 2221 - first surface of the positive electrode active material layer; 2222 - second surface of the positive electrode active material layer;

[0059] 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

[0060] To make the purpose, technical solutions and advantages of the examples of the present application clearer, the technical solutions in the examples of the present application will be described clearly and completely below. Where specific conditions are not specified in the examples, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

[0061] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0062] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art 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" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0063] 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.

[0064] In the description of the embodiments of this application, the technical term "and / or," such as "Feature 1 and / or Feature 2," refers to "Feature 1" alone, "Feature 2" alone, or "Feature 1" plus "Feature 2." Furthermore, the character " / " in this document generally indicates an "or" relationship between the preceding and following related objects.

[0065] In the description of the embodiments of the present application, unless otherwise specified, the “multiple” in “one or more” means two or more than two.

[0066] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0067] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the heights, lengths, widths, and other dimensions of the various components in the embodiments of this application, as well as the overall heights, lengths, widths, and other dimensions of the integrated device shown in the drawings are merely illustrative and do not constitute any limitation on this application.

[0068] Market developments indicate that power batteries are becoming increasingly widely used. They are not only used in energy storage systems such as hydropower, thermal, wind, and solar power plants, but are also widely used in electric vehicles like electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. As power battery applications continue to expand, market demand is also growing.

[0069] With the continued development of the new energy industry, the market has placed more diverse demands on battery electrodes. The electrolyte wettability of the positive electrode is a factor that affects battery performance. Improving the electrolyte wettability of the positive electrode can help improve the battery's rate performance and discharge capacity.

[0070] As the requirements for thicker coatings of positive electrode active material layers increase, the compaction density of positive electrode sheets increases, and the pores between the active materials are compressed and reduced, making it difficult for the electrolyte to penetrate them. In some current technical solutions, in order to improve the wetting performance, the positive electrode sheets are usually modified based on the above reasons.

[0071] However, studies have found that the floating of binders and the clogging of pores are an important factor affecting the electrolyte's ability to infiltrate the positive electrode sheets, and the current technical solutions cannot effectively remove the floating binders in the positive electrode sheets.

[0072] 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 burn and reduce the floating binder, which is beneficial to improving the blockage of the pores by the floating binder, thereby effectively improving the electrolyte infiltration performance of the positive electrode plate.

[0073] The battery cell using the positive electrode sheet disclosed in the embodiment of the present application can be used, but is not limited to, in 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. The electrical device can be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery-powered vehicle, an electric car, a ship, a spacecraft, and the like. Among them, the electric toy can include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, and the like. The spacecraft can include airplanes, rockets, space shuttles, and spacecraft, and the like.

[0074] For the convenience of explanation, the following embodiments are described by taking a vehicle as an example of an electrical device in the embodiments of the present application.

[0075] Refer to Figure 1, which is a structural schematic diagram of a vehicle 1000 provided in some embodiments of the present application. The vehicle 1000 can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can 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 can be provided at the bottom, head or tail of the vehicle 1000. The battery 100 can be used to power the vehicle 1000. For example, the battery 100 can serve as an operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. 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.

[0076] In some embodiments of the present application, the battery 100 can not only serve as the operating power source of the vehicle 1000, but also serve as the driving power source of the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0077] In this application, a battery 100 refers to a single physical module that includes one or more battery cells 20 to provide a certain voltage and capacity. It can be in the form of a battery pack, a battery module, etc. The battery 100 can include a housing 10 for enclosing the one or more battery cells 20. The housing 10 can prevent liquids or other foreign matter from affecting the charging or discharging of the battery cells 20.

[0078] Referring to FIG2 , FIG2 is an exploded view of a battery 100 provided in some embodiments of the present application. The battery 100 includes a housing 10 and a plurality of battery cells 20, wherein the plurality of battery cells 20 are housed in the housing 10. The housing 10 is used to house the battery cells 20, and the housing 10 can have various structures. In some embodiments, the housing 10 can include a first portion 11 and a second portion 12, wherein the first portion 11 and the second portion 12 overlap each other, and the first portion 11 and the second portion 12 jointly define a housing space 13 for accommodating the battery cells 20. The second portion 12 can be a hollow structure with one end open, and the first portion 11 is a plate-like structure, and the first portion 11 overlaps the open side of the second portion 12 to form the housing 10 with the housing space 13; the first portion 11 and the second portion 12 can also be hollow structures with one side open, and the open side of the first portion 11 overlaps the open side of the second portion 12 to form the housing 10 with the housing space 13. Of course, the first part 11 and the second part 12 can be in various shapes, such as a cylinder, a cuboid, etc.

[0079] In the battery 100, multiple battery cells 20 can be connected in series, in parallel, or in a hybrid configuration. A hybrid configuration refers to a combination of series and parallel connections among the multiple battery cells 20. Multiple battery cells 20 can be directly connected in series, in parallel, or in a hybrid configuration, and then the entire structure of the multiple battery cells 20 is housed within the housing 10. Alternatively, multiple battery cells 20 can be first connected in series, in parallel, or in a hybrid configuration to form a module, which is then connected in series, in parallel, or in a hybrid configuration to form a complete structure housed within the housing 10. The battery 100 may also include other structures. For example, multiple battery cells 20 can be electrically connected via a busbar to enable parallel, series, or hybrid connection of the multiple battery cells 20.

[0080] The battery cell 20 is the smallest unit that constitutes the battery pack and can be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto.

[0081] 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 accommodated in the housing 21 .

[0082] The outer shell 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. Functional components such as electrode terminals 23 and pressure relief structures 24 can also be provided on the cover 212. A sealing ring can be configured between the opening of the shell 211 and the cover 212 to achieve sealing between the shell 211 and the cover 212.

[0083] 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 material of the shell 211 and the cover 212 can be various, such as but not limited to metals such as copper, iron, aluminum, stainless steel, and aluminum alloy. The material of the sealing ring can be various, 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.

[0084] The battery cell 20 may also be in the form of a soft pack, such as a pouch-type soft pack. The soft pack may be made of plastic, such as polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0085] Referring to 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 charge and discharge process, active ions are embedded and released 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, mainly to prevent the positive and negative electrodes from short-circuiting, while allowing ions to pass through. The electrode assembly 22 can be a wound structure or a laminated structure, and the embodiments of the present application are not limited to this.

[0086] 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.

[0087] The positive electrode current collector may be a metal foil or a composite current collector. For example, the positive electrode current collector may be made of aluminum. The composite current collector may include a polymer substrate and a metal layer formed on at least one side of the polymer substrate. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer substrate (such as a substrate made of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0088] 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 oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), 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 O2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O2 (also referred to as NCM523 ), LiNi 0.5 Co 0.25 Mn 0.25 O2 (also referred to as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O2 (also referred to as NCM 622 ), LiNi 0.8 Co 0.1 Mn 0.1 O2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al 0.05 O2) and its modified compounds, etc. Examples of olivine-structured lithium-containing phosphates may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO4), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon.

[0089] In some embodiments, the positive electrode active material layer may further optionally include a binder. As an example, the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), a vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, a vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, and a fluorine-containing acrylate resin.

[0090] In some embodiments, the positive electrode active material layer may further include a conductive agent. For 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.

[0091] 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.

[0092] 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.).

[0093] 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, and lithium titanate. 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 conventional materials that can be used as negative electrode active material materials may also be used.

[0094] 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).

[0095] 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.

[0096] In some embodiments, the negative electrode active material layer may further optionally include other additives, such as a thickener (eg, sodium carboxymethyl cellulose (CMC-Na)).

[0097] The isolation membrane 223 is located between the positive electrode plate 221 and the negative electrode plate 222 and serves as an isolation. The embodiment of the present application has no particular restriction on the type of isolation membrane 223 and any well-known porous structure isolation membrane 223 with good chemical stability and mechanical stability can be selected.

[0098] In some embodiments, the material of the isolation membrane 223 can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The isolation membrane 223 can be a single-layer film or a multi-layer composite film, without particular limitation. When the isolation membrane 223 is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.

[0099] Next, the positive electrode sheet 221 and the processing method thereof proposed in the embodiment of the present application are described in detail.

[0100] 5 , in a first aspect, an embodiment of the present application provides a method for processing a positive electrode sheet, comprising: performing combustion treatment on a designated portion of the positive electrode sheet 221 , wherein the designated portion includes at least a portion of the surface of the positive active material layer of the positive electrode sheet 221 .

[0101] 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 that is 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 that is substantially parallel to the thickness direction A of the positive electrode sheet.

[0102] As an example, the designated portion includes at least the first surface 2221 of the positive electrode active material layer.

[0103] The processing method of the positive electrode plate provided in the embodiment of the present application performs a combustion treatment on the surface of the positive electrode plate 221. The flame can burn 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 infiltration performance of the positive electrode plate 221.

[0104] Furthermore, 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 was also found that the combustion process also reduces the resistance of the positive electrode sheet 221, which is beneficial for improving the electrical performance of the positive electrode sheet 221.

[0105] 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, which is 200° C. to 500° C.

[0106] As an example, the designated temperature is, but is 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 ​​therebetween.

[0107] When the combustion process is completed, it means that after the combustion process is completed and before the cooling process; for example, it means that when the burned area passes through the area where the flame is located, detection is performed within a certain distance downstream of the flame area, and the certain distance is, for example, 5cm to 20cm.

[0108] The specified temperature can be measured by a temperature measuring device such as an infrared temperature gun when the combustion process is completed.

[0109] 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 infiltration performance of the positive electrode plate 221.

[0110] In some embodiments, the designated temperature is 300°C to 500°C; alternatively, the designated temperature is 350°C to 470°C.

[0111] In these embodiments, the temperature is controlled to meet a further specified temperature so that the surface of the positive electrode active material layer can be burned at a more appropriate temperature, which is conducive to better ablation and reduction of floating binder, and can better improve the electrolyte infiltration performance of the positive electrode plate 221.

[0112] In some embodiments, the binder in the positive active material layer includes polyvinylidene fluoride.

[0113] As an example, the binder in the positive electrode active material layer is mainly polyvinylidene fluoride, for example, the binder is polyvinylidene fluoride.

[0114] Polyvinylidene fluoride, abbreviated as PVDF; the decomposition temperature is relatively low, about 280℃~350℃.

[0115] In these embodiments, the combustion treatment can effectively remove the floating binder formed by polyvinylidene fluoride, and can effectively improve the electrolyte infiltration performance of the positive electrode plate 221.

[0116] In some embodiments, the positive active material in the positive active material layer includes a lithium-containing phosphate.

[0117] 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.

[0118] Among them, lithium phosphates include Li 1+y1 Fe y2 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.

[0119] 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 can effectively remove the floating binder and improve the wetting performance while allowing the positive electrode active material layer to maintain good electrochemical properties.

[0120] In some embodiments, the lithium-containing phosphate includes lithium iron phosphate.

[0121] As an example, the lithium-containing phosphate is mainly lithium iron phosphate, for example, the lithium-containing phosphate is lithium iron phosphate.

[0122] 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, LiFePO4, abbreviated as LFP, and has a decomposition temperature of about 550℃~750℃.

[0123] 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 and improve the wetting performance while allowing the positive electrode active material layer to maintain good electrochemical performance; 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 increasingly larger compaction density, and the gaps between the positive electrode active materials are compressed smaller and smaller, resulting in the frequent problem of poor wetting performance.

[0124] In some embodiments, the combustion treatment includes burning gas and treating the designated area with the flame.

[0125] The fuel gas includes combustible gas, which is introduced into a designated location for combustion treatment through a gas delivery and ignition device D such as a spray gun or burner for combustion; during the process of delivering the fuel gas, an auxiliary fuel may optionally be delivered together with the fuel gas or separately from the fuel gas.

[0126] During the process of treating the designated portion by the generated flame, the flame heats the designated portion so that the designated portion is burned by the flame.

[0127] Optionally, the fuel gas includes one or more of methane, propane or acetylene.

[0128] As an example, the fuel gas may be one of methane, propane, and acetylene.

[0129] As another example, the fuel gas includes multiple 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.

[0130] 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 of the surface of the positive electrode plate 221.

[0131] 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.

[0132] The flow rate of a specified gas refers to the volume of the specified gas supplied per unit time.

[0133] As an example, the flow rate of the gas is, for example but not limited to, any one of 3 L / min, 4 L / min, 5 L / min, 6 L / min, 7 L / min, 8 L / min, 9 L / min, 10 L / min, 11 L / min or 12 L / min, or a range between any two of them.

[0134] 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.

[0135] 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.

[0136] 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.

[0137] In these embodiments, maintaining a suitable air flow rate during the combustion process is conducive to meeting a suitable air-fuel ratio, so that the flame can provide suitable heat to the designated area and effectively remove the floating binder at a suitable temperature to improve the infiltration performance.

[0138] In some embodiments, during the combustion process, the air-fuel ratio is (2-5):1; optionally, the air-fuel ratio is (3-4):1.

[0139] 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 ​​therebetween.

[0140] The air-fuel ratio is common knowledge in the art and has a well-known meaning in the art. It can be measured using instruments and testing methods known in the art. For example, the air-fuel ratio refers to the mass ratio between air and gas, and can be controlled by designing the flow rates of gas and air to match them. For example, gas and air are mixed at a specific flow rate based on the required air-fuel ratio, and then the mixed gas is introduced into combustion.

[0141] 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.

[0142] 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.

[0143] As an example, the designated 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.

[0144] 6 , the specified distance L refers to the vertical distance from the gas combustion port to the first surface 2221 of the positive electrode sheet, that is, the distance from the gas combustion port to the first surface 2221 of the positive electrode sheet along the thickness direction A of the positive electrode sheet.

[0145] In these embodiments, the combustion of the fuel gas is injected toward the positive electrode plate 221 at a suitable designated distance, which is beneficial for regulating the temperature of the flame acting on the positive electrode plate 221 and can effectively remove the floating binder to improve the wetting performance.

[0146] Referring to 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°.

[0147] 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.

[0148] 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.

[0149] 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.

[0150] In these embodiments, the fuel gas is injected toward the positive electrode sheet 221 at a suitable designated angle for combustion, so that the flame can better burn the positive electrode sheet 221 and more effectively remove the floating binder to improve the wetting performance.

[0151] In some embodiments, during the combustion process, the positive electrode plate 221 passes through the flame at a specified speed, which is 40 m / min to 100 m / min; optionally, the specified speed is 50 m / min to 80 m / min.

[0152] As an example, the designated speed is, but is 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 ​​therebetween.

[0153] 6 and 7 , in an embodiment of the present application, optionally, the position of the gas delivery and ignition device D for injecting and igniting the fuel gas remains fixed, and the positive electrode plate 221 is transported at a specified speed relative to the gas delivery 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.

[0154] As an example, the first surface 2221 of the positive electrode active material layer is placed flat on a conveying surface for conveyance, that is, the passing direction C of the positive electrode sheet is substantially perpendicular to the thickness direction A of the positive electrode sheet.

[0155] In these embodiments, passing the positive electrode sheet 221 through the flame at a suitable specified speed is beneficial for controlling the surface of the positive electrode sheet 221 to reach a suitable temperature, which can effectively remove the floating binder to improve the wetting performance.

[0156] In some exemplary embodiments, the positive electrode sheet 221 includes first edges relatively distributed along a first direction and second edges relatively distributed along a second direction; exemplarily, the first direction and the second direction are two directions perpendicular to each other. During the combustion process, 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 electrode active material layer in the first direction (i.e., it can cover from one side edge in the first direction to the opposite side edge), so that after the entire positive electrode sheet 221 passes through the flame along the second direction, the entire first surface 2221 of the positive electrode active material layer facing the flame is burned.

[0157] 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.

[0158] In some embodiments, the wetting speed of the positive electrode plate 221 to the electrolyte is greater than 0.27 μg / s. Optionally, the wetting speed of the positive electrode plate 221 to the electrolyte is greater than or equal to 0.33 μg / s.

[0159] In these embodiments, the positive electrode plate 221 has a relatively high wetting speed for the electrolyte, and the positive electrode plate 221 has relatively good electrolyte wetting performance.

[0160] 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%.

[0161] In these embodiments, the positive electrode plate 221 has a relatively high porosity, which is beneficial for improving the electrolyte infiltration performance of the positive electrode plate 221 .

[0162] 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.

[0163] In a fourth aspect, an embodiment of the present application provides an electrical device, comprising a battery 100 as described in the above embodiment.

[0164] Some specific embodiments are listed below to better illustrate the present application.

[0165] 1. Processing of the positive electrode

[0166] (1) Preparation of positive electrode sheet

[0167] Lithium iron phosphate (LFP), conductive agent carbon black, polyvinylidene fluoride (PVDF), and N-methylpyrrolidone (NMP) are stirred and mixed in a weight ratio of 97:2:1:21 to obtain a positive electrode slurry; the positive electrode slurry is then evenly coated on the positive electrode collector, and then dried, cold pressed, and cut to obtain a positive electrode sheet.

[0168] (2) Surface treatment of the positive electrode

[0169] The positive electrode sheet is placed in a conveying device, the fuel gas is ignited, and the positive electrode sheet is passed through the flame by the conveying device, so that the first surface of the entire active material layer facing the flame is treated by the flame.

[0170] 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. are shown in Figures 6 and 7; the process parameter conditions such as the 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, and the specified speed are shown in Table 1.

[0171]

[0172] Table 1. Process parameter conditions

[0173]

[0174] In Table 1, Comparative Example 1 indicates that the positive electrode sheet was not subjected to combustion treatment.

[0175] In addition, it should be noted that because the composition of the gas and air used in different embodiments may vary slightly, the difference in the gas-to-air flow ratio and the difference in the air-fuel ratio between different embodiments are not necessarily 1:1 related. For example, the gas-to-air flow ratio is different between Example 1 and Example 2, but the air-fuel ratio is the same.

[0176] 2. Test Method

[0177] (1) Specified temperature detection

[0178] 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 8 cm downstream of the flame area to obtain the specified temperature.

[0179] (2) Electrolyte wetting performance test

[0180] Fix the positive electrode sheet on a clean glass plate; draw electrolyte from a height of 3mm through a 0.2mm capillary tube and make vertical contact with the positive electrode sheet to allow the positive electrode sheet 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.

[0181] (3) Porosity detection

[0182] In a dry room, use tweezers to select >20 discs with good appearance and no powdering on the edges and place them into a sample cup. Record the number of discs and calculate the apparent volume. Place the sample cup containing the sample in a true density tester. Close the test system and introduce helium according to the program. By measuring the gas pressure in the sample chamber and expansion chamber, calculate the true volume according to Bohr's law (PV = nRT) to obtain the porosity of the sample.

[0183] (4) Resistance detection

[0184] Cut small 10mm diameter discs from the left, center, and right sides of the positive electrode sheet. Turn on the indicator light on the Yuanneng Technology Sheet Resistance Meter, place the discs in the appropriate position on the "probe" of the sheet resistance meter, click the "Start" button, and wait for the reading to stabilize before reading. Test two locations on each disc. Calculate the average of the six measurements to obtain the sheet resistance of the positive electrode sheet.

[0185] (5) Adhesion test

[0186] Cut the positive electrode sheet into 20*100mm 2 The test specimens of the required size are kept aside; the double-sided tape is used to adhere the side of the specimen to be tested, and is compacted with a pressure roller to ensure that the double-sided tape is completely adhered to the specimen; 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°; a high-speed rail tensile testing machine is used for testing, one end of the stainless steel is fixed to the lower fixture of the tensile testing machine, and the bent end of the specimen is fixed to the upper fixture, and 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 forces are balanced is the bonding force of the positive electrode sheet.

[0187] 3. Test results and analysis

[0188] The test results of the positive electrode are shown in Table 2.

[0189] Table 2

[0190]

[0191] Combining Table 1 and Table 2, a brief analysis is as follows:

[0192] In Examples 1 through 21, the positive electrode sheets were subjected to a combustion treatment; in Comparative Example 1, the positive electrode sheets were not subjected to a combustion treatment. Compared to Comparative Example 1, Examples 1 through 21 showed varying degrees of improvement in the wetting rate and porosity of the positive electrode sheets. Furthermore, compared to Comparative Example 1, Examples 1 through 21 maintained good adhesion, and the sheet resistance not only did not deteriorate but also decreased to varying degrees.

[0193] In Examples 1 to 21, when the surface temperature of the electrode reaches above 300° C., and further reaches above 350° C., the wetting rate and porosity of the positive electrode can reach a relatively good level.

[0194] 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 make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions 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, wherein: 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, wherein: 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, wherein: 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, wherein: 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, wherein: 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, wherein: 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, wherein: 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, wherein: 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, wherein: 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, wherein: 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, wherein: 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, wherein: 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, wherein: 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, wherein: 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, wherein: 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, wherein: 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, wherein: It comprises the positive electrode sheet as claimed in any one of claims 14 to 16.

18. An electrical device, wherein: Comprising the battery of claim 17.

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