WO2024259956A1 - 正极极片的制备方法、正极极片、电池单体、电池和用电装置 - Google Patents

正极极片的制备方法、正极极片、电池单体、电池和用电装置 Download PDF

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Publication number
WO2024259956A1
WO2024259956A1 PCT/CN2024/071053 CN2024071053W WO2024259956A1 WO 2024259956 A1 WO2024259956 A1 WO 2024259956A1 CN 2024071053 W CN2024071053 W CN 2024071053W WO 2024259956 A1 WO2024259956 A1 WO 2024259956A1
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Prior art keywords
positive electrode
preparation
diisocyanate
battery
electrode sheet
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PCT/CN2024/071053
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English (en)
French (fr)
Inventor
赵鑫
刘会会
段连威
贺泽炜
周永斌
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Contemporary Amperex Technology Co Ltd
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Contemporary Amperex Technology Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/621—Binders
    • H01M4/622—Binders being polymers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • H01M4/0402—Methods of deposition of the material
    • H01M4/0404—Methods of deposition of the material by coating on electrode collectors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/136—Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1397—Processes of manufacture of electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application relates to the field of battery technology, and in particular to a method for preparing a positive electrode sheet, a positive electrode sheet, a battery cell, a battery and an electrical device.
  • lithium-ion batteries are widely used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, as well as power tools, electric bicycles, electric motorcycles, electric vehicles, military equipment, aerospace and other fields.
  • the performance of the positive electrode sheet is crucial to the performance of the battery. Therefore, how to provide a positive electrode sheet to improve the performance of the battery is a technical problem that needs to be solved urgently.
  • the present application is made in view of the above-mentioned technical problems, and its purpose is to provide a method for preparing a positive electrode sheet, to prepare a positive electrode sheet with good performance, and to improve the performance of a battery containing the positive electrode sheet.
  • the embodiments of the present application provide a method for preparing a positive electrode sheet, a positive electrode sheet, a battery cell, a battery and an electrical device.
  • a method for preparing a positive electrode sheet comprising: preparing a positive electrode slurry, wherein the positive electrode slurry comprises a polyurethane prepolymer; applying the positive electrode slurry to at least one side of a positive electrode current collector; The positive electrode slurry coated on at least one side of the positive electrode current collector is dried to obtain the positive electrode sheet.
  • the positive electrode slurry includes a polyurethane prepolymer, and after the positive electrode slurry is coated on at least one side of the positive electrode current collector, the positive electrode slurry coated on at least one side of the positive electrode current collector is dried.
  • the polyurethane prepolymer in the positive electrode slurry will be cross-linked and cured to form a polyurethane cross-linked substance with a large molecular weight.
  • the polyurethane cross-linked substance has a cross-linked network structure and a long molecular chain substance.
  • the polyurethane prepolymer that has not been cross-linked and cured has a lower viscosity.
  • the solid content of the polyurethane binder in the positive electrode slurry can be increased, and the positive electrode slurry is easy to disperse during coating, thereby improving the processing efficiency of the positive electrode sheet.
  • the polyurethane prepolymer is cross-linked and cured to form a large molecular weight cross-linked substance with good bonding strength and toughness, which can improve the performance of the positive electrode sheet and thus improve the performance of the battery.
  • the drying temperature of the positive electrode slurry is in the range of 60°C to 150°C.
  • the drying temperature is in the range of 80°C to 140°C.
  • Conductive agents collect microcurrents between active materials to reduce the contact resistance of the electrode and accelerate the movement rate of electrons. They can also effectively increase the migration rate of metal ions in the electrode material, thereby improving the charge and discharge efficiency of the electrode.
  • Dispersants are conducive to the uniform dispersion of solids in the positive electrode slurry in the solvent.
  • Crosslinking agents are conducive to catalyzing the crosslinking and curing of polyurethane prepolymers. Including the above substances in the positive electrode slurry is conducive to the preparation of positive electrode sheets with good performance.
  • the conductive agent includes at least one of conductive carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
  • carbon material conductive agent Due to the unique composition of carbon structure, carbon material conductive agent has good conductivity.
  • Conductive carbon black has the advantages of low resistance and high conductivity, small particle size, large and rough specific surface area, high structure, clean surface (few compounds), etc.
  • Ketjen black has a unique branched morphology, so it has high conductivity; carbon atoms in carbon nanotubes adopt SP2 hybridization, so they have high modulus and high strength. Carbon nanotubes also have good flexibility, stretchability and conductivity.
  • Conductive carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers can be used as conductive agents to improve the conductivity of batteries.
  • the dispersant includes polyvinyl pyrrolidone.
  • Polyvinyl pyrrolidone has good stability and has the advantages of colloidal protection, film-forming, adhesiveness, hygroscopicity, solubilization or coagulation in the reaction system.
  • the cross-linking agent includes at least one of sucrose, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diethyltoluenediamine, dimethylthiotoluenediamine, three-arm polycaprolactone, and four-arm polycaprolactone.
  • the preparing the binder precursor solution includes: preparing the polyurethane prepolymer; dispersing the polyurethane prepolymer in N-methylpyrrolidone solvent to obtain the binder precursor solution.
  • the preparation of the polyurethane prepolymer includes: drying polyether polyol and/or polyester polyol; mixing the dried polyether polyol and/or polyester polyol with isocyanate and a catalyst to carry out a prepolymerization reaction; after the prepolymerization reaction is completed, adding a blocking agent to the reaction product to obtain the polyurethane prepolymer.
  • the drying temperature of the polyether polyol and/or the polyester polyol is in the range of 90° C. to 95° C., and the drying time is in the range of 2 to 3 hours.
  • the drying temperature and drying time are set within the above ranges, which is beneficial for the polyether polyol and/or polyester polyol to reach a state suitable for polymerization reaction, and is beneficial for prepolymerization reaction with isocyanate.
  • the isocyanate includes diisocyanate, and the diisocyanate includes at least one of aromatic diisocyanate and aliphatic diisocyanate.
  • the isocyanate includes at least one of isotoluene-2,3-diisocyanate, toluene-2,4-diisocyanate, toluene-2,5-diisocyanate, toluene-2,6-diisocyanate, toluene-3,4-diisocyanate, toluene-3,5-diisocyanate, 1,5-naphthalene diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, L-lysine ethyl diisocyanate, hydrogenated toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, and hydrogenated diphenylmethane diisocyanate.
  • the molar ratio R of isocyanate to hydroxyl in the polyurethane prepolymer is in the range of 1.1 to 2.0.
  • the molar ratio R is in the range of 1.2 to 1.8.
  • the molar ratio of isocyanate to hydroxyl in the polyurethane prepolymer is set within the above range, which is conducive to the subsequent cross-linking and curing reaction of the polyurethane prepolymer.
  • the polyether polyol includes at least one of polyethylene glycol, polypropylene oxide glycol, polyethylene oxide glycol, polytetramethylene glycol, and polyethylene glycol-propylene glycol copolymer.
  • the polyester polyol includes at least one of polycaprolactone, polycarbonate diol, polylactic acid diol, and polyglycolide-lactide copolymer.
  • the catalyst includes at least one of an organic tin catalyst, an organic bismuth catalyst, and a tertiary amine catalyst.
  • the catalyst includes at least one of dibutyltin dilaurate, stannous octoate, N-ethylmorpholine, N-methylmorpholine, and triethylamine.
  • the above substances can effectively catalyze the prepolymerization reaction of polyether polyol and/or polyester polyol with isocyanate.
  • the blocking agent includes at least one of trichloroethanol, trifluoroethanol, dodecyl mercaptan, triphenyl mercaptan, hexanethiol, N,N-butanediol acetamide, ethylene glycol monohexyl ether, N,N-diol amide, phenol, pyridine, methyl ethyl ketone oxime, caprolactam, and ethyl acetoacetate.
  • the mass percentage content of the catalyst in the reaction raw materials for the prepolymerization reaction ranges from 0.001% to 1.0%.
  • Controlling the catalyst within the above range is beneficial to catalyzing the prepolymerization reaction of polyether polyol and/or polyester polyol with isocyanate.
  • a positive electrode sheet is provided which is produced by the production method according to the first aspect and any possible implementation thereof.
  • the positive electrode plate includes a positive electrode active material layer, and based on the total mass of the positive electrode active material layer, the mass percentage of the binder in the positive electrode active material layer is in a range of 0.3% to 4.2%.
  • the mass percentage of the binder in the positive electrode active material layer is set within the above range, which is beneficial to improving the performance of the positive electrode sheet.
  • a battery cell comprising the positive electrode plate described in the second aspect.
  • a battery comprising the battery cell described in the third aspect.
  • the embodiment of the present application provides a method for preparing a positive electrode sheet, wherein the positive electrode slurry includes a polyurethane prepolymer, and after the positive electrode slurry is coated on at least one side of the positive electrode current collector, the positive electrode slurry coated on at least one side of the positive electrode current collector is dried.
  • the polyurethane prepolymer in the positive electrode slurry will be cross-linked and cured to form a polyurethane cross-linked substance with a large molecular weight, and the polyurethane cross-linked substance has a cross-linked network structure and a long molecular chain structure.
  • polyurethane is conducive to improving the transmission rate of active metal ions (such as lithium ions), thereby improving the internal resistance of the battery and improving the cycle performance of the battery.
  • FIG1 is a schematic diagram of a method for preparing a positive electrode sheet according to an embodiment of the present application
  • FIG2 is a schematic diagram of a positive electrode sheet according to an embodiment of the present application.
  • FIG3 is a schematic diagram of a positive electrode sheet according to an embodiment of the present application.
  • FIG4 is a schematic diagram of a method for preparing a positive electrode sheet according to an embodiment of the present application.
  • FIG5 is a schematic diagram of a method for preparing a positive electrode sheet according to an embodiment of the present application.
  • FIG6 is a schematic diagram of a method for preparing a positive electrode sheet according to an embodiment of the present application.
  • FIG7 is a schematic diagram of a battery cell disclosed in an embodiment of the present application.
  • FIG8 is a schematic diagram of an exploded structure of a battery cell disclosed in an embodiment of the present application.
  • FIG9 is a schematic diagram of an exploded structure of a battery disclosed in an embodiment of the present application.
  • FIG10 is a schematic diagram of an electrical device disclosed in an embodiment of the present application.
  • ranges are defined in the form of lower limits and upper limits, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of the particular range. Ranges defined in this manner may be inclusive or exclusive of the end values and may be combined arbitrarily, i.e., any lower limit may be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a particular parameter, it is understood that ranges of 60-110 and 80-120 are also contemplated.
  • the maximum value listed is Small range values 1 and 2, and if the maximum range values 3, 4 and 5 are listed, the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5.
  • the numerical range “ab” represents an abbreviation of any real number combination between a and b, where a and b are both real numbers.
  • the numerical range "0-5" means that all real numbers between "0-5" have been listed in this document, and "0-5" is just an abbreviation of these numerical combinations.
  • a parameter is expressed as an integer ⁇ 2, it is equivalent to disclosing that the parameter is, for example, an integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.
  • the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially.
  • the method may further include step (c), which means that step (c) may be added to the method in any order.
  • the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.
  • the term "and/or” is inclusive.
  • the phrase “A and/or B” means “A, B, or both A and B”. More specifically, any of the following conditions satisfies the condition "A and/or B”: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).
  • Secondary batteries are widely used in mobile phones, electric vehicles, power stations, etc. due to their high energy density, high voltage, long life, etc.
  • the performance of the positive electrode is crucial to the performance of the battery.
  • Binder is an important factor affecting the performance of positive electrode sheets.
  • binders are usually added to the positive electrode slurry.
  • the positive electrode active material and the conductive agent are adhered to the positive electrode collector by the binder to maintain the structural stability of the positive electrode sheet.
  • Polyurethane binders are widely used because of their good bonding force, storage stability and more active metal ion channels.
  • the molecular weight of the cross-linked and cured polyurethane binder is relatively large. Adding it to the positive electrode slurry will greatly increase the viscosity of the positive electrode slurry and reduce the uniformity of the solid dispersion in the positive electrode slurry.
  • the molecular weight of the polyurethane binder must be controlled not to be too large, which greatly reduces the bonding performance of the polyurethane binder and is not conducive to the preparation of positive electrode sheets with good performance.
  • the embodiment of the present application provides a method for preparing a positive electrode sheet, wherein a polyurethane prepolymer is included in the positive electrode slurry, and after the positive electrode slurry is coated on at least one side of the positive electrode current collector, the positive electrode slurry coated on at least one side of the positive electrode current collector is dried.
  • the polyurethane prepolymer in the positive electrode slurry is cross-linked and cured to form a polyurethane cross-linked substance with a large molecular weight.
  • the polyurethane cross-linked substance has a cross-linked network structure and a long molecular chain structure.
  • the polyurethane prepolymer that has not been cross-linked and cured has a lower viscosity.
  • the solid content of the polyurethane binder in the positive electrode slurry can be increased, and the positive electrode slurry is easy to disperse during coating, thereby improving the processing efficiency of the positive electrode sheet.
  • the polyurethane prepolymer is cross-linked and cured to form a large molecular weight cross-linked substance with good bonding strength and toughness, which can improve the performance of the positive electrode sheet and thus improve the performance of the battery.
  • Fig. 1 is a schematic diagram of a method for preparing a positive electrode sheet according to an embodiment of the present application. As shown in Fig. 1 , the preparation method includes the following steps.
  • Step 101 preparing positive electrode slurry.
  • the positive electrode slurry includes polyurethane prepolymer.
  • Step 102 coating the positive electrode slurry on at least one side of the positive electrode current collector.
  • Step 103 drying the positive electrode slurry coated on at least one side of the positive electrode current collector to obtain a positive electrode sheet.
  • a positive electrode slurry containing a polyurethane prepolymer is provided, and after the positive electrode slurry is coated on at least one side of the positive electrode current collector, the positive electrode slurry coated on at least one side of the positive electrode current collector is dried.
  • the polyurethane prepolymer in the positive electrode slurry will be cross-linked and cured to form a polyurethane cross-linked substance with a large molecular weight.
  • the polyurethane cross-linked substance has a cross-linked network structure and a long molecular chain structure.
  • the polyurethane prepolymer that has not been cross-linked and cured has a lower viscosity.
  • the solid content of the polyurethane binder in the positive electrode slurry can be increased, and the positive electrode slurry is easy to disperse during coating, thereby improving the processing efficiency of the positive electrode sheet.
  • the polyurethane prepolymer is cross-linked and cured to form a large molecular weight cross-linked substance with good bonding strength and toughness, which can improve the performance of the positive electrode sheet and thus improve the performance of the battery.
  • FIG2 is a schematic diagram of a positive electrode sheet of an embodiment of the present application.
  • the positive electrode sheet 2 includes a positive electrode current collector 21 and a positive electrode material layer 22.
  • the positive electrode material layer 22 is formed by coating the positive electrode slurry on the positive electrode current collector 21 and drying it.
  • the positive electrode current collector 21 and the positive electrode material layer 22 are sequentially arranged.
  • the positive electrode current collector 21 has two surfaces arranged along the thickness direction thereof.
  • positive electrode material layers 22 are arranged on both surfaces of the positive electrode current collector 21 .
  • Fig. 3 is a schematic diagram of a positive electrode sheet according to an embodiment of the present application.
  • a positive electrode material layer 22 is disposed on one of two surfaces of the positive electrode current collector 21 that are opposite to each other in the thickness direction.
  • the drying temperature of the positive electrode slurry ranges from 60°C to 150°C.
  • the drying temperature ranges from 80°C to 140°C.
  • the drying temperature of the positive electrode slurry can be 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, or a value between any two of the above values.
  • the drying temperature of the positive electrode slurry is set within the above range, which is conducive to the cross-linking and curing of the polyurethane prepolymer and the drying of the slurry, and is conducive to the preparation of a positive electrode sheet with good performance.
  • preparing the positive electrode slurry includes: preparing a binder precursor solution, adding a positive electrode active material, a conductive agent, a dispersant and a cross-linking agent to the binder precursor solution, mixing, and preparing the positive electrode slurry.
  • FIG. 4 is a schematic diagram of a method for preparing a positive electrode sheet according to an embodiment of the present application. Steps 403-404 in FIG. 4 are similar to steps 102-103 in the aforementioned embodiment, and can refer to the aforementioned embodiment. For the sake of brevity, they will not be repeated here.
  • Step 401 preparing a binder precursor solution.
  • Step 402 Add positive electrode active material, conductive agent, dispersant and cross-linking agent into the binder precursor solution, mix them, and prepare positive electrode slurry.
  • Conductive agents collect microcurrents between active materials to reduce the contact resistance of the electrode and accelerate the movement rate of electrons. They can also effectively increase the migration rate of metal ions in the electrode material, thereby improving the charge and discharge efficiency of the electrode.
  • Dispersants are conducive to the uniform dispersion of solids in the positive electrode slurry in the solvent.
  • Crosslinking agents are conducive to catalyzing the crosslinking and curing of polyurethane prepolymers. Including the above substances in the positive electrode slurry is conducive to the preparation of positive electrode sheets with good performance.
  • the conductive agent includes at least one of conductive carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
  • carbon material conductive agent Due to the unique composition of carbon structure, carbon material conductive agent has good conductivity.
  • conductive carbon black has low resistance and high conductivity, small particle size, large and rough specific surface area, high structure, clean surface (few compounds), etc.
  • Ketjen black has a unique branched chain morphology, so it has high conductivity; carbon atoms in carbon nanotubes adopt SP 2 hybridization, so they have high modulus and high strength. Carbon nanotubes also have good flexibility and durability. Stretchability and conductivity.
  • Conductive carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers can be used as conductive agents to improve the conductivity of batteries.
  • the dispersant comprises polyvinyl pyrrolidone.
  • Polyvinyl pyrrolidone has good stability and has the advantages of colloidal protection, film-forming, adhesiveness, hygroscopicity, solubilization or coagulation in the reaction system.
  • the cross-linking agent includes at least one of sucrose, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diethyltoluenediamine, dimethylthiotoluenediamine, three-arm polycaprolactone, and four-arm polycaprolactone.
  • preparing the binder precursor solution includes: preparing a polyurethane prepolymer; dispersing the polyurethane prepolymer in an N-methylpyrrolidone solvent to obtain a binder precursor solution.
  • FIG. 5 is a schematic diagram of a method for preparing a positive electrode sheet according to an embodiment of the present application. Steps 503-505 in FIG. 5 are similar to steps 402-404 in the aforementioned embodiment, and can refer to the aforementioned embodiment. For the sake of brevity, they will not be described here.
  • Step 501 preparing a polyurethane prepolymer.
  • Step 502 Disperse the polyurethane prepolymer in N-methylpyrrolidone solvent to obtain a binder precursor solution.
  • providing a polyurethane prepolymer includes: drying polyether polyol, and/or polyester polyol; mixing the dried polyether polyol, and/or polyester polyol with isocyanate and a catalyst to perform a prepolymerization reaction; after the prepolymerization reaction is completed, adding a blocking agent to the reaction product to obtain a polyurethane prepolymer.
  • Figure 6 is a schematic diagram of a method for preparing a positive electrode plate of an embodiment of the present application. Steps 604-607 in Figure 6 are similar to steps 502-505 in the aforementioned embodiment, and can refer to the aforementioned embodiment. For the sake of brevity, they will not be repeated here.
  • Step 601 drying polyether polyol and/or polyester polyol.
  • Step 602 Mix the dried polyether polyol and/or polyester polyol with isocyanate and a catalyst to perform a prepolymerization reaction.
  • Step 603 adding a blocking agent to the reaction product of the prepolymerization reaction to obtain a polyurethane prepolymer.
  • the drying temperature of the polyether polyol and/or the polyester polyol is in the range of 90° C. to 95° C.
  • the drying time is in the range of 2 to 3 hours.
  • the drying temperature of the polyether polyol and/or polyester polyol can be 90°C, 91°C, 92°C, 93°C, 94°C, 95°C, or a value between any two of the above values; the drying time can be 2 hours, 2.5 hours, 3 hours, or a value between any two of the above values.
  • the drying temperature and drying time are set within the above ranges, which is beneficial for the polyether polyol and/or polyester polyol to reach a state suitable for polymerization reaction, and is beneficial for prepolymerization reaction with isocyanate.
  • the isocyanate includes a diisocyanate, and optionally, the diisocyanate includes at least one of an aromatic diisocyanate and an aliphatic diisocyanate.
  • the isocyanate may include at least one of isotoluene-2,3-diisocyanate, toluene-2,4-diisocyanate, toluene-2,5-diisocyanate, toluene-2,6-diisocyanate, toluene-3,4-diisocyanate, toluene-3,5-diisocyanate, 1,5-naphthalene diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, L-lysine ethyl diisocyanate, hydrogenated toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, and hydrogenated diphenylmethane diisocyanate.
  • the polyether polyol includes at least one of polyethylene glycol, polypropylene oxide glycol, polyethylene oxide glycol, polytetramethylene glycol, and polyethylene glycol-propylene glycol copolymer.
  • the polyester polyol includes at least one of polycaprolactone, polycarbonate diol, polylactic acid diol, and polyglycolide-lactide copolymer.
  • the molar ratio R of isocyanate to hydroxyl in the polyurethane prepolymer is in the range of 1.1 to 2.0.
  • R is in the range of 1.2 to 1.8.
  • the molar ratio R of isocyanate to hydroxyl in the polyurethane prepolymer can be 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, or a value between any two of the above values.
  • the molar ratio of isocyanate to hydroxyl in the polyurethane prepolymer is set within the above range, which is conducive to the subsequent cross-linking and curing reaction of the polyurethane prepolymer.
  • the catalyst includes at least one of an organic tin catalyst, an organic bismuth catalyst, and a tertiary amine catalyst.
  • the catalyst may include at least one of dibutyltin dilaurate, stannous octoate, N-ethylmorpholine, N-methylmorpholine, and triethylamine.
  • the above substances can effectively catalyze the prepolymerization reaction of polyether polyol and/or polyester polyol with isocyanate.
  • the sealing agent includes at least one of trichloroethanol, trifluoroethanol, dodecyl mercaptan, triphenyl mercaptan, hexanethiol, N,N-butanediol acetamide, ethylene glycol monohexyl ether, N,N-diol amide, phenol, pyridine, methyl ethyl ketone oxime, caprolactam, and ethyl acetoacetate.
  • the mass percentage of the catalyst in the reaction raw materials for the prepolymerization reaction ranges from 0.001% to 1.0%.
  • the mass percentage of the catalyst in the reaction raw materials of the prepolymerization reaction can be 0.001%, 0.01%, 0.05%, 0.1%, 0.5%, 1.0%, or a value between any two of the above values.
  • the embodiment of the present application provides a positive electrode plate manufactured according to the above-mentioned manufacturing method.
  • the positive electrode plate 2 includes a positive electrode current collector 21 and a positive electrode material layer 22 .
  • the positive electrode material layer 22 includes a binder. Based on the total mass of the positive electrode material layer 22 , the mass percentage of the binder in the positive electrode material layer 22 ranges from 0.3% to 4.2%.
  • the mass percentage of the binder in the positive electrode material layer 22 can be 0.3%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.2%, or a value between any two of the above values.
  • the adhesive comprises a polyurethane adhesive, which has excellent shear strength and impact resistance, and has excellent flexibility.
  • the positive electrode current collector may be a metal foil or a composite current collector.
  • aluminum foil may be used as the metal foil.
  • the composite current collector may include a polymer material base and a metal layer formed on at least one surface of the polymer material base.
  • 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 material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PET polyethylene terephthalate
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the positive electrode material layer includes a positive electrode active material
  • the positive electrode active material can be a positive electrode active material for lithium ion batteries known in the art.
  • the positive electrode active material may include at least one of the following materials: an olivine-structured lithium-containing phosphate, a lithium transition metal oxide, and their respective modified compounds.
  • the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials for lithium ion batteries can also be used. These positive electrode active materials can be used alone or in combination of two or more.
  • 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 LiNi1 /3Co1 / 3Mn1/ 3O2 (also referred to as NCM333), LiNi0.5Co0.2Mn0.3O2 (also referred to as NCM523 ), LiNi0.5Co0.25Mn0.25O2 (also referred to as NCM211), LiNi0.6Co0.2Mn0.2O2 (also referred to as NCM622), LiNi0.8Co0.1Mn0.1O2 (also referred to as NCM811), lithium nickel cobalt aluminum oxide (such as LiNi0.85Co0.2Mn0.3O2 ) , LiNi0.5Co0.2M
  • lithium-containing phosphates with an olivine structure may include, but are not limited to, at least one of lithium iron phosphate (such as LiFePO 4 (also referred to as LFP)), a composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon.
  • lithium iron phosphate such as LiFePO 4 (also referred to as LFP)
  • LiMnPO 4 lithium manganese phosphate
  • LiMnPO 4 lithium manganese phosphate
  • LiMnPO 4 lithium manganese phosphate and carbon
  • the binder may also 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.
  • PVDF polyvinylidene fluoride
  • PTFE polytetrafluoroethylene
  • PTFE polytetrafluoroethylene
  • vinylidene fluoride-tetrafluoroethylene-propylene terpolymer vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer
  • tetrafluoroethylene-hexafluoropropylene copolymer tetrafluoroethylene-he
  • the negative electrode current collector may be a metal foil or a composite current collector.
  • the metal foil copper foil may be used.
  • the composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material substrate.
  • the composite current collector may 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 a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PET polyethylene terephthalate
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the negative electrode active material may adopt the negative electrode active material for the battery known in the art.
  • 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.
  • the present application is not limited to these materials, and other traditional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.
  • the negative electrode film 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).
  • the negative electrode film 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.
  • 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.
  • the negative electrode film layer may optionally include other additives, such as a thickener (eg, sodium carboxymethyl cellulose (CMC-Na)).
  • a thickener eg, sodium carboxymethyl cellulose (CMC-Na)
  • the negative electrode sheet can be prepared in the following manner: the components for preparing the negative electrode sheet, such as the negative electrode active material, the conductive agent, the binder and any other components are dispersed in a solvent (such as deionized water) to form a negative electrode slurry; the negative electrode slurry is coated on the negative electrode collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained.
  • a solvent such as deionized water
  • the electrolyte plays the role of conducting ions between the positive electrode and the negative electrode.
  • the present application has no specific restrictions on the type of electrolyte, which can be selected according to needs.
  • the electrolyte can be liquid, gel or all-solid.
  • the electrolyte is an electrolyte solution, which includes an electrolyte salt and a solvent.
  • the electrolyte salt can be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalatoborate, lithium dioxalatoborate, lithium difluorodioxalatophosphate, and lithium tetrafluorooxalatophosphate.
  • the electrolyte may further include additives, such as negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high or low temperature performance, etc.
  • additives such as negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain battery properties, such as additives that improve battery overcharge performance, additives that improve battery high or low temperature performance, etc.
  • the positive electrode sheet, the negative electrode sheet, and the separator may be formed into an electrode assembly by a winding process or a lamination process.
  • the battery cell may include an outer packaging, which may be used to encapsulate the electrode assembly and the electrolyte.
  • the outer packaging of the battery cell may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc.
  • the outer packaging of the battery cell may also be a soft package, such as a bag-type soft package.
  • the material of the soft package may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, and polybutylene succinate.
  • FIG7 is a battery cell 70 of a square structure as an example.
  • the outer package may include a shell 71 and a cover plate 73.
  • the shell 71 may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate enclose a receiving cavity.
  • the shell 71 has an opening connected to the receiving cavity, and the cover plate 73 can be covered on the opening to close the receiving cavity.
  • the positive electrode sheet, the negative electrode sheet and the isolation film can form an electrode assembly 72 through a winding process or a lamination process.
  • the electrode assembly 72 is encapsulated in the receiving cavity.
  • the electrolyte is infiltrated in the electrode assembly 72.
  • the number of electrode assemblies 72 contained in the battery cell 70 can be one or more, and those skilled in the art can select according to specific actual needs.
  • the battery 80 may include a plurality of battery cells 70.
  • FIG. 9 which is a schematic diagram of the structure of a battery 80 according to an embodiment of the present application, the battery 80 may include a plurality of battery cells 70.
  • the battery 80 may also include a box 81, the interior of the box 81 is a hollow structure, and the plurality of battery cells 70 are accommodated in the box 81.
  • the plurality of battery cells 70 are connected in parallel, in series, or in a mixed combination and then placed in the box 81.
  • the battery 80 may also include other structures, which are not described one by one here.
  • the battery 80 may also include a busbar component, which is used to realize electrical connection between multiple battery cells 70, such as parallel connection, series connection or mixed connection.
  • the busbar component can realize electrical connection between battery cells 70 by connecting the electrode terminals of the battery cells 70.
  • the busbar component can be fixed to the electrode terminals of the battery cells 70 by welding.
  • the electrical energy of multiple battery cells 70 can be further led out through the box 81 through a conductive mechanism.
  • the conductive mechanism may also belong to the busbar component.
  • the number of battery cells 70 can be set to any value. Multiple battery cells 70 can be connected in series, parallel or hybrid to achieve a larger capacity or power. Since the number of battery cells 70 included in each battery 80 may be large, for ease of installation, the battery cells 70 can be grouped, and each group of battery cells 70 constitutes a battery module. The number of battery cells 70 included in the battery module is not limited and can be set according to demand.
  • the battery can include multiple battery modules, which can be connected in series, parallel or hybrid.
  • the present application also provides an electric device, which includes at least one of the battery cells, battery modules or batteries provided in the present application.
  • the battery cells, battery modules or batteries can be used as the power source of the electric device, and can also be used as the energy storage unit of the electric device.
  • the electric device may include mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but are not limited thereto.
  • a battery cell, a battery module or a battery can be selected according to its usage requirements.
  • the positive electrode slurry prepared above was scraped onto a carbon-coated aluminum foil and baked at a temperature of 110° C. for 15 minutes to obtain a positive electrode sheet 1.
  • the detection of the isocyanate group (-NCO) content mentioned above can be carried out according to the detection method of the isocyanate group content provided by the national standard GB/T12009.4.
  • the theoretical value of the -NCO content is a theoretical value obtained by theoretical calculation based on the ratio of the reaction raw materials of the polyurethane prepolymerization reaction in the embodiment.
  • Positive electrode plate 2 The preparation of positive electrode plate 2 is similar to that of positive electrode plate 1, except that, in the process of preparing positive electrode plate 2, the amount of hexamethylene diisocyanate added is 20.177 kg, the amount of catalyst triethylamine added is 2.473 g, the amount of sealing agent methyl ethyl ketone oxime added is 3.485 kg, and the amount of cross-linking agent triethylenetetramine added is 0.975 kg, so as to obtain positive electrode plate 2.
  • Positive electrode sheet 3 The preparation of positive electrode sheet 3 is similar to that of positive electrode sheet 1, except that, in the process of preparing positive electrode sheet 3, the amount of hexamethylene diisocyanate added is 21.858 kg, the amount of catalyst triethylamine added is 2.542 g, the amount of sealing agent methyl ethyl ketone oxime added is 5.227 kg, and the amount of cross-linking agent triethylenetetramine added is 1.462 kg, so as to obtain positive electrode sheet 3.
  • Positive electrode plate 4 The preparation of positive electrode plate 4 is similar to that of positive electrode plate 1, except that, in the process of preparing positive electrode plate 4, the amount of hexamethylene diisocyanate added is 23.540 kg, the amount of catalyst triethylamine added is 2.610 g, the amount of sealing agent methyl ethyl ketone oxime added is 6.970 kg, and the amount of cross-linking agent triethylenetetramine added is 1.950 kg, so as to obtain positive electrode plate 4.
  • Positive electrode sheet 5 The preparation of positive electrode sheet 5 is similar to that of positive electrode sheet 1. The difference is that in the process of preparing positive electrode sheet 5, the amount of hexamethylene diisocyanate added is 25.221 kg, and the amount of catalyst triethylamine added is 2.679g, the added amount of sealing agent methyl ethyl ketone oxime is 8.712kg, and the added amount of cross-linking agent triethylenetetramine is 2.437kg, and the positive electrode plate 5 is prepared.
  • Positive electrode plate 6 The preparation of positive electrode plate 6 is similar to that of positive electrode plate 1, except that, in the process of preparing positive electrode plate 6, the amount of hexamethylene diisocyanate added is 26.902 kg, the amount of catalyst triethylamine added is 2.747 g, the amount of sealing agent methyl ethyl ketone oxime added is 10.454 kg, and the amount of cross-linking agent triethylenetetramine added is 2.925 kg, so as to obtain positive electrode plate 6.
  • Positive electrode plate 7 The preparation of positive electrode plate 7 is similar to that of positive electrode plate 1, except that, in the process of preparing positive electrode plate 7, the amount of hexamethylene diisocyanate added is 28.584 kg, the amount of catalyst triethylamine added is 2.816 g, the amount of sealing agent methyl ethyl ketone oxime added is 12.197 kg, and the amount of cross-linking agent triethylenetetramine added is 3.412 kg, so as to obtain positive electrode plate 7.
  • Positive electrode plate 8 The preparation of positive electrode plate 8 is similar to that of positive electrode plate 1, except that, in the process of preparing positive electrode plate 8, the amount of hexamethylene diisocyanate added is 30.265 kg, the amount of catalyst triethylamine added is 2.884 g, the amount of sealing agent methyl ethyl ketone oxime added is 13.939 kg, and the amount of cross-linking agent triethylenetetramine added is 3.899 kg, so as to obtain positive electrode plate 8.
  • Positive electrode plate 9 The preparation of positive electrode plate 9 is similar to that of positive electrode plate 1, except that, in the process of preparing positive electrode plate 9, the amount of hexamethylene diisocyanate added is 33.638 kg, the amount of catalyst triethylamine added is 3.021 g, the amount of sealing agent methyl ethyl ketone oxime added is 17.424 kg, and the amount of cross-linking agent triethylenetetramine added is 4.874 kg, so as to obtain positive electrode plate 9.
  • Positive electrode plate 10 The preparation of positive electrode plate 10 is similar to that of positive electrode plate 1, except that, in the process of preparing positive electrode plate 10, the amount of PEG added is 60.000 kg, and 40.000 kg of polybutylene glycol (PTMG, molecular weight 1000) is added as a reaction raw material of polyurethane prepolymer, the amount of hexamethylene diisocyanate added is 25.221 kg, the amount of catalyst triethylamine added is 2.679 g, the amount of sealing agent methyl ethyl ketone oxime added is 8.712 kg, and the amount of cross-linking agent triethylenetetramine added is 2.437 kg, so as to obtain positive electrode plate 10.
  • PTMG polybutylene glycol
  • Positive electrode plate 11 The preparation of positive electrode plate 11 is similar to that of positive electrode plate 1, except that, in the process of preparing positive electrode plate 11, the amount of PEG added is 60.000 kg, and 40.000 kg of polycaprolactone (PCL, molecular weight 1000) is added as a reaction raw material of polyurethane prepolymer, the amount of hexamethylene diisocyanate added is 25.221 kg, the amount of catalyst triethylamine added is 2.679 g, the amount of sealing agent methyl ethyl ketone oxime added is 8.712 kg, and the amount of cross-linking agent triethylenetetramine added is 2.437 kg, so as to obtain positive electrode plate 11.
  • PCL polycaprolactone
  • Positive electrode plate 12 The preparation of positive electrode plate 12 is similar to that of positive electrode plate 1, except that, in the process of preparing positive electrode plate 12, the amount of PEG added is 60.000 kg, and 40.000 kg of polycarbonate diol (PCDL, molecular weight 1000) is added as a reaction raw material of polyurethane prepolymer, the amount of hexamethylene diisocyanate added is 25.221 kg, the amount of catalyst triethylamine added is 2.679 g, the amount of sealing agent methyl ethyl ketone oxime added is 8.712 kg, and the amount of cross-linking agent triethylenetetramine added is 2.437 kg, so as to obtain positive electrode plate 12.
  • PCDL polycarbonate diol
  • Positive electrode plate 13 The preparation of positive electrode plate 13 is similar to that of positive electrode plate 1, except that, in the process of preparing positive electrode plate 13, the amount of PEG added is 60.000 kg, and 40.000 kg of polypropylene glycol (PPG, molecular weight 1000) is added as a reaction raw material of polyurethane prepolymer, the amount of hexamethylene diisocyanate added is 25.221 kg, the amount of catalyst triethylamine added is 2.679 g, the amount of sealing agent methyl ethyl ketone oxime added is 8.712 kg, and the amount of cross-linking agent triethylenetetramine added is 2.437 kg, so as to obtain positive electrode plate 13.
  • PPG polypropylene glycol
  • Positive electrode plate 14 The preparation of positive electrode plate 14 is similar to that of positive electrode plate 1, except that, in the process of preparing positive electrode plate 14, the amount of PEG added is 60.000 kg, and 40.000 kg of polydimethylsiloxane (PDMS, molecular weight 1000) is added as a reaction raw material of polyurethane prepolymer, the amount of hexamethylene diisocyanate added is 25.221 kg, the amount of catalyst triethylamine added is 2.679 g, the amount of sealing agent methyl ethyl ketone oxime added is 8.712 kg, and the amount of cross-linking agent triethylenetetramine added is 2.437 kg, so as to obtain positive electrode plate 14.
  • PDMS polydimethylsiloxane
  • Positive electrode sheet 15 The preparation of positive electrode sheet 15 is similar to that of positive electrode sheet 1, except that, in the process of preparing positive electrode sheet 15, the amount of PEG added is 60.000 kg, and 40.000 kg of polylactic acid-hydroxyacetic acid copolymer (PLGA, molecular weight 1000) is added as the reaction raw material of polyurethane prepolymer, the amount of hexamethylene diisocyanate added is 25.221 kg, the amount of catalyst triethylamine added is 2.679 g, the amount of sealing agent methyl ethyl ketone oxime added is 8.712 kg, and the amount of cross-linking agent triethylenetetramine added is 2.437 kg, so as to obtain positive electrode sheet 15.
  • PLGA polylactic acid-hydroxyacetic acid copolymer
  • Positive electrode sheet 16 Add 100.000 kg of polyethylene glycol (PEG, molecular weight 1000) to the reactor and dry it at 95°C for 3 hours. Then add 25.221 kg of hexamethylene diisocyanate, 2.679 g of catalyst triethylamine, and 0.487 kg of cross-linking agent triethylenetetramine to the reactor, and react at 115°C to obtain a polyurethane adhesive.
  • PEG polyethylene glycol
  • the positive electrode slurry prepared above was scraped onto a carbon-coated aluminum foil and baked at a temperature of 110° C. for 15 minutes to obtain a positive electrode sheet 16 .
  • Positive electrode sheet 17 3.97 kg of positive electrode active material LiFePO 4 , 16.4 g of binder polyvinylidene fluoride, and 57.4 g of conductive agent acetylene black were placed in a planetary stirring tank, and stirred at an orbital speed of 25 r/min for 20 min. 2.4 kg of NMP solution was added to the stirring tank, and stirred at an orbital speed of 25 r/min and a self-rotation speed of 900 r/min for 50 min. 12.3 g of dispersant PVP was added to the stirring tank, and stirred at an orbital speed of 25 r/min and a self-rotation speed of 1400 r/min for 50 min to prepare a positive electrode slurry.
  • the positive electrode slurry prepared above was scraped onto the carbon-coated aluminum foil and baked at 110° C. for 15 min to obtain the positive electrode sheet 17 .
  • the dried positive electrode slurry in the prepared positive electrode sheet is scraped off from the positive electrode collector and dissolved with NMP solution.
  • the polyurethane therein cannot be redissolved due to its large molecular weight and remains solid in the solvent.
  • the positive electrode sheet adopts the positive electrode sheet 1 prepared as above.
  • lithium salt LiPF 6
  • EMC ethylene carbonate
  • DEC diethyl carbonate
  • VC additive vinylene carbonate
  • the positive electrode sheet, the isolation film, and the negative electrode sheet are stacked in order, so that the isolation film is placed between the positive electrode sheet and the negative electrode sheet to play an isolating role, and then wound to obtain an electrode assembly; the electrode assembly is placed in a battery casing, and after drying, the electrolyte is injected, and then a lithium-ion battery 1 is obtained through processes such as formation and standing, as Example 1.
  • Adhesive 180° Peel Strength Test Method use a blade to cut a positive electrode sheet with a width of 30mm and a length of 100-160mm, and stick a special double-sided tape on the steel plate.
  • the double-sided tape is 20mm wide and 90-150mm long. Stick the cut positive electrode sheet on the double-sided tape with the test side facing down, and then roll it three times in the same direction with a roller.
  • the prepared positive electrode was tested using a four-probe resistance meter. Three parallel samples were tested for each sample and the average value was taken.
  • the batteries of the embodiments and comparative examples are charged to 3.65V at 0.5C constant current, and then charged to 0.05C at constant voltage; the battery is discharged at 0.5C constant current for 60 minutes to adjust the battery to 50% SOC, at which time the battery voltage is recorded as U1; the battery is discharged at 4C constant current for 30 seconds, with 0.1 second sampling, and the voltage at the end of discharge is recorded as U2.
  • the lithium-ion battery is charged to 3.65V at a constant current of 1/3C, then charged to a current of 0.05C at a constant voltage of 3.65V, left for 5 minutes, and then discharged to 2.5V at 1/3C.
  • the obtained capacity is recorded as the initial capacity C0.
  • the battery capacity retention rate (%) after n cycles (Cn/C0) ⁇ 100%.
  • the capacity retention rate (%) of a lithium-ion battery after 500 cycles at 25° C. (discharge capacity at the 500th cycle/discharge capacity at the first cycle) ⁇ 100%.
  • the product parameters of different embodiments and comparative examples, as well as the test results of the performance tests of the prepared positive electrode sheets 1-17 according to the above method, are shown in Table 1.
  • the R value of the polyurethane prepolymer in Table 1 refers to the molar ratio of isocyanate to hydroxyl in the polyurethane prepolymer as R.
  • the test results of the battery performance tests of the prepared comparative examples 1-2 and embodiments 1-15 according to the above method are shown in Table 2.
  • the positive electrode slurry contains a polyurethane prepolymer
  • the prepared positive electrode sheet has good bonding force and a small film resistance of the positive electrode sheet.
  • the corresponding lithium-ion battery has a small DCR and a good capacity retention rate of the lithium-ion battery.
  • the molar ratio R of isocyanate to hydroxyl in the polyurethane prepolymer is controlled within the range of 1.2 to 1.8, the bonding force of the positive electrode sheet is better, and the film resistance of the positive electrode sheet is also smaller; the corresponding DCR of the lithium ion battery is smaller, and the capacity retention rate of the lithium ion battery is better.

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Abstract

提供一种正极极片的制备方法、正极极片、电池单体、电池和用电装置。正极极片的制备方法包括：制备正极浆料，其中，正极浆料包括聚氨酯预聚体；将正极浆料涂覆于正极集流体的至少一侧；将涂覆于正极集流体的至少一侧的正极浆料烘干，制得正极极片；可以提升电池的性能。

Description

正极极片的制备方法、正极极片、电池单体、电池和用电装置
相关申请的交叉引用
本申请要求享有于2023年06月21日提交的名称为“正极极片的制备方法、正极极片、电池单体、电池和用电装置”的中国专利申请202310745048.4的优先权，该申请的全部内容通过引用并入本文中。
技术领域
本申请涉及电池技术领域，特别是涉及一种正极极片的制备方法、正极极片、电池单体、电池和用电装置。
背景技术
近年来，锂离子电池的应用范围越来越广泛，其广泛应用于水力、火力、风力和太阳能电站等储能电源系统，以及电动工具、电动自行车、电动摩托车、电动汽车、军事装备、航空航天等多个领域。
正极极片作为电池的组成部分，正极极片的性能对于电池的性能至关重要。因此，如何提供一种正极极片，以提高电池的性能是一项亟待解决的技术问题。
发明内容
本申请是鉴于上述技术问题而进行的，其目的在于，提供一种正极极片的制备方法，制备性能良好的正极极片，含有该正极极片的电池的性能有所提升。
为了达到上述目的，本申请实施例提供了一种正极极片的制备方法、正极极片、电池单体、电池和用电装置。
第一方面，提供了一种正极极片的制备方法，包括：制备正极浆料，其中，所述正极浆料包括聚氨酯预聚体；将所述正极浆料涂覆于正极集流体的至少一侧；将 涂覆于所述正极集流体的至少一侧的所述正极浆料烘干，制得所述正极极片。
本申请实施例提供的正极极片的制备方法中，正极浆料中包括聚氨酯预聚体，将正极浆料涂覆在正极集流体的至少一侧后，烘干涂覆于正极集流体的至少一侧的正极浆料，在烘干正极浆料的过程中，正极浆料中的聚氨酯预聚体会进行交联固化，形成大分子量的聚氨酯交联物质，聚氨酯交联物质中具有交联网状结构，具有长的分子链物质，相较于一般的晶体状粘结剂物质，具有良好的粘结强度和韧性，从而提高正极极片的韧性，得到性能良好的正极极片。同时，聚氨酯有利于提升活性金属离子(比如，锂离子)的传输速率，从而改善电池的内阻，提升电池的循环性能。本申请实施例提供的技术方案中，未进行交联固化的聚氨酯预聚体具有较低的粘度，添加到正极浆料中，可以提高正极浆料中聚氨酯粘结剂的固含量，且正极浆料在涂覆时易于分散，提高正极极片的加工效率。在烘干涂覆于正极集流体的至少一侧的正极浆料的过程中，聚氨酯预聚体进行交联固化，形成大分子量的交联物质，具有良好的粘结强度和韧性，可以提高正极极片的性能，从而提升电池的性能。
在一种可能的实现方式中，所述正极浆料的烘干温度的取值范围为60℃～150℃，可选地，所述烘干温度的取值范围为80℃～140℃。
正极浆料的烘干温度设置在上述范围内，有利于聚氨酯预聚体的交联固化以及浆料的干燥，有利于制备出性能良好的正极极片。
在一种可能的实现方式中，所述制备正极浆料包括：制备粘结剂前驱体溶液，在所述粘结剂前驱体溶液中加入正极活性材料、导电剂、分散剂和交联剂，混合，制得所述正极浆料。
导电剂在活性材料之间起到收集微电流的作用，以减小电极的接触电阻加速电子的移动速率，同时也能有效地提高金属离子在电极材料中的迁移速率，从而提高电极的充放电效率；分散剂有利于正极浆料中固体物在溶剂中分散均匀；交联剂有利于催化聚氨酯预聚体的交联固化。正极浆料中包括上述物质，有利于制备出性能良好的正极极片。
在一种可能的实现方式中，所述导电剂包括导电炭、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的至少一种。
由于碳结构的独特组成成分，碳材料导电剂具备良好的导电性能。比如， 导电炭黑具有低电阻属性和高导电性能，粒径小，比表面积大且粗糙，结构高，表面洁净(化合物少)等优点；科琴黑具有独特的支链状形态，因而导电性高；碳纳米管中碳原子采取SP2杂化，因而具有高模量和高强度，碳纳米管还具有良好的柔韧性、可拉伸性和导电性能。导电炭、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯和碳纳米纤维作为导电剂可以提升电池的导电性能。
在一种可能的实现方式中，所述分散剂包括聚乙烯吡咯烷酮。
聚乙烯吡咯烷酮稳定性好，在反应体系中具有胶体保护作用、成膜性、粘结性、吸湿性、增溶或凝聚作用等优点。
在一种可能的实现方式中，所述交联剂包括蔗糖、二乙烯三胺、三乙烯四胺、四乙烯五胺、二乙基甲苯二胺、二甲硫基甲苯二胺、三臂聚己内酯、四臂聚己内酯中的至少一种。
在一种可能的实现方式中，所述制备粘结剂前驱体溶液包括：制备所述聚氨酯预聚体；将所述聚氨酯预聚体分散于N-甲基吡咯烷酮溶剂，制得所述粘结剂前驱体溶液。
在一种可能的实现方式中，所述制备所述聚氨酯预聚体包括：干燥聚醚多元醇，和/或，聚酯多元醇；将干燥后的所述聚醚多元醇，和/或，所述聚酯多元醇与异氰酸酯和催化剂混合，进行预聚反应；所述预聚反应结束后，向反应产物中加入封闭剂，制得所述聚氨酯预聚体。
在预聚反应的反应产物中加入封闭剂，封闭剂可以使得异氰酸根活性基团在较低温度下失去活性，涂布后的极片在烘箱中经过高温烘烤时，封闭剂失去作用，使得异氰酸根暴露。
在一种可能的实现方式中，所述聚醚多元醇，和/或，所述聚酯多元醇的干燥温度的取值范围为90℃～95℃，干燥时间的取值范围为2～3小时。
干燥温度和干燥时间设置在上述范围内，有利于聚醚多元醇，和/或，聚酯多元醇达到适宜发生聚合反应的状态，有利于与异氰酸酯进行预聚反应。
在一种可能的实现方式中，所述异氰酸酯包括二异氰酸酯，所述二异氰酸酯包括芳香族二异氰酸酯、脂肪族二异氰酸酯中的至少一种。
在一种可能的实现方式中，所述异氰酸酯包括异甲苯-2,3-二异氰酸酯、甲苯-2,4-二异氰酸酯、甲苯-2,5-二异氰酸酯、甲苯-2,6-二异氰酸酯、甲苯-3,4-二异氰酸酯、甲苯-3,5-二异氰酸酯、1,5-萘二异氰酸酯、对苯二异氰酸酯、间苯二异氰酸酯、六亚甲基二异氰酸酯、五亚甲基二异氰酸酯、L-赖氨酸乙酯二异氰酸酯、氢化甲苯二异氰酸酯、异佛尔酮二异氰酸酯、二苯基甲烷二异氰酸酯、氢化二苯基甲烷二异氰酸酯中的至少一种。
在一种可能的实现方式中，所述聚氨酯预聚体中的异氰酸根与羟基的摩尔比值R的取值范围为1.1～2.0，可选地，R的取值范围为1.2～1.8。
聚氨酯预聚体中的异氰酸根与羟基的摩尔比值设置在上述范围内，有利于后续聚氨酯预聚体的交联固化反应的进行。
在一种可能的实现方式中，所述聚醚多元醇包括聚乙二醇、聚环氧丙烷二醇、聚环氧乙烷二醇、聚四氢呋喃醚二醇、聚乙二醇-丙二醇共聚物中的至少一种。
在一种可能的实现方式中，所述聚酯多元醇包括聚己内酯、聚碳酸酯二醇、聚乳酸二醇、聚乙交酯-丙交酯共聚物中的至少一种。
在一种可能的实现方式中，所述催化剂包括有机锡类催化剂、有机铋类催化剂、叔胺类催化剂中的至少一种。
在一种可能的实现方式中，所述催化剂包括二丁基锡二月桂酸酯、辛酸亚锡、N-乙基吗啉、N-甲基吗啉、三乙胺中的至少一种。
上述物质可以有效催化聚醚多元醇，和/或，聚酯多元醇与异氰酸酯的预聚反应。
在一种可能的实现方式中，所述封闭剂包括三氯乙醇、三氟乙醇、十二烷基硫醇、三苯基硫醇、己硫醇、N,N-丁二醇乙酰胺、乙二醇单己醚、N,N-二醇酰胺、苯酚、吡啶、甲乙酮肟、己内酰胺、乙酰乙酸乙酯中的至少一种。
在一种可能的实现方式中，基于所述预聚反应的反应原料的总质量计，所述催化剂在所述预聚反应的反应原料中的质量百分含量的取值范围为0.001％～1.0％。
控制催化剂在上述范围内，有利于催化聚醚多元醇，和/或，聚酯多元醇与异氰酸酯的预聚反应。
第二方面，提供一种根据第一方面及其中任一项可能的实现方式中的制备方法制得的正极极片。
在一种可能的实现方式中，所述正极极片包括正极活性材料层，基于所述正极活性材料层的总质量计，所述正极活性材料层中的粘结剂在所述正极材料层中的质量百分含量的取值范围为0.3％～4.2％。
正极活性材料层中的粘结剂的质量百分含量设置在上述范围内，有利于正极极片性能的提升。
第三方面，提供了一种电池单体，包括第二方面所述的正极极片。
第四方面，提供了一种电池，包括第三方面所述的电池单体。
第五方面，提供了一种用电装置，包括第四方面所述的电池。
本申请实施例提供了一种正极极片的制备方法，正极浆料中包括聚氨酯预聚体，将正极浆料涂覆在正极集流体的至少一侧后，烘干涂覆于正极集流体的至少一侧的正极浆料，在烘干正极浆料的过程中，正极浆料中的聚氨酯预聚体会进行交联固化，形成大分子量的聚氨酯交联物质，聚氨酯交联物质中具有交联网状结构，具有长的分子链结构，相较于一般的晶体状粘结剂物质，具有良好的粘结强度和韧性，从而提高正极极片的韧性，得到性能良好的正极极片。同时，聚氨酯有利于提升活性金属离子(比如，锂离子)的传输速率，从而改善电池的内阻，提升电池的循环性能。本申请实施例提供的技术方案中，未进行交联固化的聚氨酯预聚体具有较低的粘度，添加到正极浆料中，可以提高正极浆料中聚氨酯粘结剂的固含量，且正极浆料在涂覆时易于分散，提高正极极片的加工效率。在烘干涂覆于正极集流体的至少一侧的正极浆料的过程中，聚氨酯预聚体进行交联固化，形成大分子量的交联物质，具有良好的粘结强度和韧性，可以提高正极极片的性能，从而提升电池的性能。
附图说明
为了更清楚地说明本申请实施例的技术方案，下面将对本申请实施例中所需要使用的附图作简单地介绍，显而易见地，下面所描述的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据附图获得其他的附图。
图1为本申请一实施例的正极极片的制备方法的示意图；
图2为本申请一实施例的正极极片的示意图；
图3为本申请一实施例的正极极片的示意图；
图4为本申请一实施例的正极极片的制备方法的示意图；
图5为本申请一实施例的正极极片的制备方法的示意图；
图6为本申请一实施例的正极极片的制备方法的示意图；
图7是本申请一实施例公开的一种电池单体的示意图；
图8是本申请一实施例公开的一种电池单体的分解结构示意图；
图9是本申请一实施例公开的一种电池的分解结构示意图；
图10是本申请一实施例公开的一种用电装置的示意图；
在附图中，附图并未按照实际的比例绘制。
具体实施方式
下面将结合附图，对本申请实施例中的技术方案进行描述。
以下，适当地参照附图详细说明具体公开了本申请电极极片、电池单体、电池和用电装置的实施方式。但是会有省略不必要的详细说明的情况。例如，有省略对已众所周知的事项的详细说明、实际相同结构的重复说明的情况。这是为了避免以下的说明不必要地变得冗长，便于本领域技术人员的理解。此外，附图及以下说明是为了本领域技术人员充分理解本申请而提供的，并不旨在限定权利要求书所记载的主题。
在本申请的描述中，需要说明的是，除非另有说明，“多个”的含义是两个以上；术语“上”、“下”、“左”、“右”、“内”、“外”等指示的方位或位置关系仅是为了便于描述本申请和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本申请的限制。此外，术语“第一”、“第二”、“第三”等仅用于描述目的，而不能理解为指示或暗示相对重要性。
本申请所公开的“范围”以下限和上限的形式来限定，给定范围是通过选定一个下限和一个上限进行限定的，选定的下限和上限限定了特别范围的边界。这种方式进行限定的范围可以是包括端值或不包括端值的，并且可以进行任意地组合，即任何下限可以与任何上限组合形成一个范围。例如，如果针对特定参数列出了60-120和80-110的范围，理解为60-110和80-120的范围也是预料到的。此外，如果列出的最 小范围值1和2，和如果列出了最大范围值3，4和5，则下面的范围可全部预料到：1-3、1-4、1-5、2-3、2-4和2-5。在本申请中，除非有其他说明，数值范围“a-b”表示a到b之间的任意实数组合的缩略表示，其中a和b都是实数。例如数值范围“0-5”表示本文中已经全部列出了“0-5”之间的全部实数，“0-5”只是这些数值组合的缩略表示。另外，当表述某个参数为≥2的整数，则相当于公开了该参数为例如整数2、3、4、5、6、7、8、9、10、11、12等。
如果没有特别的说明，本申请的所有步骤可以顺序进行，也可以随机进行，优选是顺序进行的。例如，所述方法包括步骤(a)和(b)，表示所述方法可包括顺序进行的步骤(a)和(b)，也可以包括顺序进行的步骤(b)和(a)。例如，所述提到所述方法还可包括步骤(c)，表示步骤(c)可以任意顺序加入到所述方法，例如，所述方法可以包括步骤(a)、(b)和(c)，也可包括步骤(a)、(c)和(b)，也可以包括步骤(c)、(a)和(b)等。
如果没有特别的说明，本申请所提到的“包括”和“包含”表示开放式。例如，所述“包括”和“包含”可以表示包括或包含没有列出的其他组分。
如果没有特别的说明，在本申请中，术语“和/或”是包括性的。举例来说，短语“A和/或B”表示“A，B，或A和B两者”。更具体地，以下任一条件均满足条件“A和/或B”：A为真(或存在)并且B为假(或不存在)；A为假(或不存在)而B为真(或存在)；或A和B都为真(或存在)。
如果没有特别的说明，本申请的所有实施方式以及可选实施方式可以相互组合形成新的技术方案。
如果没有特别的说明，本申请的所有技术特征以及可选技术特征可以相互组合形成新的技术方案。
二次电池因其高能量密度、高电压、长寿命等特点被广泛应用于移动手机、电动车辆、储电站等领域。正极极片作为电池的组成部分，正极极片的性能对于电池的性能至关重要。
粘结剂是影响正极极片性能的重要因素，在正极极片的制备过程中，通常会在正极浆料中添加粘结剂，通过粘结剂将正极活性物质和导电剂粘附在正极集流体上，保持正极极片的结构稳定性。聚氨酯粘结剂因其具有好的粘结力、存储稳定性和更多的活性金属离子通道而受到广泛的应用。但交联固化后的聚氨酯粘结剂分子量较大，添加到正极浆料中会大幅提高正极浆料的粘度，降低正极浆料中固体物的分散均匀性，正极浆料涂覆到正极集流体上时，难以涂抹均匀，增加了生产难度，降低生产效率。且为了保证正极浆料的可用性，还需控制聚氨酯粘结剂的分子量不能太大，这就使得聚氨酯粘结剂的粘结性能大打折扣，不利于制备性能良好的正极极片。
鉴于此，本申请实施例提供了一种正极极片的制备方法，在正极浆料中包括聚氨酯预聚体，将正极浆料涂覆在正极集流体的至少一侧后，烘干涂覆在正极集流体的至少一侧的正极浆料，在烘干正极浆料的过程中，正极浆料中的聚氨酯预聚体会进行交联固化，形成大分子量的聚氨酯交联物质，聚氨酯交联物质中具有交联网状结构，具有长的分子链结构，相较于一般的晶体状粘结剂物质，具有良好的粘结强度和韧性，从而提高正极极片的韧性，得到性能良好的正极极片，。同时，聚氨酯有利于提升活性金属离子(比如，锂离子)的传输速率，从而改善电池的内阻，提升电池的循环性能。本申请实施例提供的技术方案中，未进行交联固化的聚氨酯预聚体具有较低的粘度，添加到正极浆料中，可以提高正极浆料中聚氨酯粘结剂的固含量，且正极浆料在涂覆时易于分散，提高正极极片的加工效率。在烘干涂覆于正极集流体的至少一侧的正极浆料的过程中，聚氨酯预聚体进行交联固化，形成大分子量的交联物质，具有良好的粘结强度和韧性，可以提高正极极片的性能，从而提升电池的性能。
以下，具体介绍本申请的多个实施例。
[正极极片的制备方法]
图1为本申请一实施例的正极极片的制备方法的示意图。如图1所示，制备方法包括以下步骤。
步骤101，制备正极浆料。
其中，正极浆料包括聚氨酯预聚体。
步骤102，将正极浆料涂覆于正极集流体的至少一侧。
步骤103，将涂覆于正极集流体的至少一侧的正极浆料烘干，制得正极极片。
本申请实施例提供的正极极片的制备方法中，提供含有聚氨酯预聚体的正极浆料，将正极浆料涂覆在正极集流体的至少一侧后，烘干涂覆于正极集流体的至少一侧的正极浆料，在烘干正极浆料的过程中，正极浆料中的聚氨酯预聚体会进行交联固化，形成大分子量的聚氨酯交联物质，聚氨酯交联物质中具有交联网状结构，具有长的分子链结构，相较于一般的晶体状粘结剂物质，具有良好的粘结强度和韧性，从而提高正极极片的韧性，得到性能良好的正极极片。同时，聚氨酯有利于提升活性金属离子(比如，锂离子)的传输速率，从而改善电池的内阻，提升电池的循环性能。本申请实施例提供的技术方案中，未进行交联固化的聚氨酯预聚体具有较低的粘度，添加到正极浆料中，可以提高正极浆料中聚氨酯粘结剂的固含量，且正极浆料在涂覆时易于分散，提高正极极片的加工效率。在烘干涂覆于正极集流体的至少一侧的正极浆料的过程中，聚氨酯预聚体进行交联固化，形成大分子量的交联物质，具有良好的粘结强度和韧性，可以提高正极极片的性能，从而提升电池的性能。
图2为本申请一实施例的正极极片的示意图。如图2所示，正极极片2包括正极集流体21和正极材料层22，正极材料层22由上述正极浆料涂覆于正极集流体21后，烘干形成，沿正极极片2的厚度方向(比如，图2中的z方向)，正极集流体21和正极材料层22依次设置。
正极集流体21具有沿其厚度方向设置的两个表面。可选地，如图1所示，正极集流体21的两个表面均设置有正极材料层22。
图3为本申请一实施例的正极极片的示意图。在一些其它实施例中，如图3所示，正极集流体21的沿厚度方向相对的两个表面中的一个表面设置有正极材料层22。
可选地，在一些实施例中，正极浆料的烘干温度的取值范围为60℃～150℃，可选地，烘干温度的取值范围为80℃～140℃。
具体地，正极浆料的烘干温度可以为60℃、70℃、80℃、90℃、100℃、110℃、120℃、130℃、140℃、150℃，或是以上任意两个数值之间的数值。
正极浆料的烘干温度设置在上述范围内，有利于聚氨酯预聚体的交联固化以及浆料的干燥，有利于制备出性能良好的正极极片。
可选地，在一些实施例中，制备正极浆料包括：制备粘结剂前驱体溶液，在粘结剂前驱体溶液中加入正极活性材料、导电剂、分散剂和交联剂，混合，制得正极浆料。参考图4，图4为本申请一实施例的正极极片的制备方法的示意图。图4中的步骤403-404与前述实施例中的步骤102-103类似，可以参考前述实施例，为了简洁，在此不再赘述。
步骤401，制备粘结剂前驱体溶液。
步骤402，在粘结剂前驱体溶液中加入正极活性材料、导电剂、分散剂和交联剂，混合，制得正极浆料。
导电剂在活性材料之间起到收集微电流的作用，以减小电极的接触电阻加速电子的移动速率，同时也能有效地提高金属离子在电极材料中的迁移速率，从而提高电极的充放电效率；分散剂有利于正极浆料中固体物在溶剂中分散均匀；交联剂有利于催化聚氨酯预聚体的交联固化。正极浆料中包括上述物质，有利于制备出性能良好的正极极片。
可选地，在一些实施例中，导电剂包括导电炭、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的至少一种。
由于碳结构的独特组成成分，碳材料导电剂具备良好的导电性能。比如，导电炭黑具有低电阻属性和高导电性能，粒径小，比表面积大且粗糙，结构高，表面洁净(化合物少)等优点；科琴黑具有独特的支链状形态，因而导电性高；碳纳米管中碳原子采取SP2杂化，因而具有高模量和高强度，碳纳米管还具有良好的柔韧性、可 拉伸性和导电性能。导电炭、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯和碳纳米纤维作为导电剂可以提升电池的导电性能。
可选地，在一些实施例中，分散剂包括聚乙烯吡咯烷酮。
聚乙烯吡咯烷酮稳定性好，在反应体系中具有胶体保护作用、成膜性、粘结性、吸湿性、增溶或凝聚作用等优点。
可选地，在一些实施例中，交联剂包括蔗糖、二乙烯三胺、三乙烯四胺、四乙烯五胺、二乙基甲苯二胺、二甲硫基甲苯二胺、三臂聚己内酯、四臂聚己内酯中的至少一种。
可选地，在一些实施例中，制备粘结剂前驱体溶液包括：制备聚氨酯预聚体；将聚氨酯预聚体分散于N-甲基吡咯烷酮溶剂，制得粘结剂前驱体溶液。参考图5，图5为本申请一实施例的正极极片的制备方法的示意图。图5中的步骤503-505与前述实施例中的步骤402-404类似，可以参考前述实施例，为了简洁，在此不再赘述。
步骤501，制备聚氨酯预聚体。
步骤502，将聚氨酯预聚体分散于N-甲基吡咯烷酮溶剂，制得粘结剂前驱体溶液。
可选地，在一些实施例中，提供聚氨酯预聚体包括：干燥聚醚多元醇，和/或，聚酯多元醇；将干燥后的聚醚多元醇，和/或，聚酯多元醇与异氰酸酯和催化剂混合，进行预聚反应；预聚反应结束后，向反应产物中加入封闭剂，制得聚氨酯预聚体。参考图6，图6为本申请一实施例的正极极片的制备方法的示意图。图6中的步骤604-607与前述实施例中的步骤502-505类似，可以参考前述实施例，为了简洁，在此不再赘述。
步骤601，干燥聚醚多元醇，和/或，聚酯多元醇。
步骤602，将干燥后的聚醚多元醇，和/或，聚酯多元醇与异氰酸酯和催化剂混合，进行预聚反应。
步骤603，向预聚反应的反应产物中加入封闭剂，制得聚氨酯预聚体。
在预聚反应的反应产物中加入封闭剂，封闭剂可以使得异氰酸根活性基团在较低温度下失去活性，涂布后的极片在烘箱中经过高温烘烤时，封闭剂失去作用，使得异氰酸根暴露。
可选地，在一些实施例中，聚醚多元醇，和/或，聚酯多元醇的干燥温度的取值范围为90℃～95℃，干燥时间的取值范围为2～3小时。
具体地，聚醚多元醇，和/或，聚酯多元醇的干燥温度可以为90℃、91℃、92℃、93℃、94℃、95℃，或是以上任意两个数值之间的数值；干燥时间可以为2小时、2.5小时、3小时，或是以上任意两个数值之间的数值。
干燥温度和干燥时间设置在上述范围内，有利于聚醚多元醇，和/或，聚酯多元醇达到适宜发生聚合反应的状态，有利于与异氰酸酯进行预聚反应。
可选地，在一些实施例中，异氰酸酯包括二异氰酸酯，可选地，二异氰酸酯包括芳香族二异氰酸酯、脂肪族二异氰酸酯中的至少一种。
具体地，异氰酸酯可以包括异甲苯-2,3-二异氰酸酯、甲苯-2,4-二异氰酸酯、甲苯-2,5-二异氰酸酯、甲苯-2,6-二异氰酸酯、甲苯-3,4-二异氰酸酯、甲苯-3,5-二异氰酸酯、1,5-萘二异氰酸酯、对苯二异氰酸酯、间苯二异氰酸酯、六亚甲基二异氰酸酯、五亚甲基二异氰酸酯、L-赖氨酸乙酯二异氰酸酯、氢化甲苯二异氰酸酯、异佛尔酮二异氰酸酯、二苯基甲烷二异氰酸酯、氢化二苯基甲烷二异氰酸酯中的至少一种。
可选地，在一些实施例中，聚醚多元醇包括聚乙二醇、聚环氧丙烷二醇、聚环氧乙烷二醇、聚四氢呋喃醚二醇、聚乙二醇-丙二醇共聚物中的至少一种。
可选地，在一些实施例中，聚酯多元醇包括聚己内酯、聚碳酸酯二醇、聚乳酸二醇、聚乙交酯-丙交酯共聚物中的至少一种。
可选地，在一些实施例中，聚氨酯预聚体中的异氰酸根与羟基的摩尔比值R的取值范围为1.1～2.0，可选地，R的取值范围为1.2～1.8。
具体地，聚氨酯预聚体中的异氰酸根与羟基的摩尔比值R可以为1.1、1.2、1.3、1.4、1.5、1.6、1.7、1.8、1.9、2.0，或是以上任意两个数值之间的数值。
聚氨酯预聚体中的异氰酸根与羟基的摩尔比值设置在上述范围内，有利于后续聚氨酯预聚体的交联固化反应的进行。
可选地，在一些实施例中，催化剂包括有机锡类催化剂、有机铋类催化剂、叔胺类催化剂中的至少一种。
具体地，催化剂可以包括二丁基锡二月桂酸酯、辛酸亚锡、N-乙基吗啉、N-甲基吗啉、三乙胺中的至少一种。
上述物质可以有效催化聚醚多元醇，和/或，聚酯多元醇与异氰酸酯的预聚反应。
可选地，在一些实施例中，封闭剂包括三氯乙醇、三氟乙醇、十二烷基硫醇、三苯基硫醇、己硫醇、N,N-丁二醇乙酰胺、乙二醇单己醚、N,N-二醇酰胺、苯酚、吡啶、甲乙酮肟、己内酰胺、乙酰乙酸乙酯中的至少一种。
可选地，在一些实施例中，基于预聚反应的反应原料的总质量计，催化剂在预聚反应的反应原料中的质量百分含量的取值范围为0.001％～1.0％。
具体地，催化剂在预聚反应的反应原料中的质量百分含量可以为0.001％、0.01％、0.05％、0.1％、0.5％、1.0％，或是以上任意两个数值之间的数值。
[正极极片]
本申请实施例提供一种根据上述制备方法制得的正极极片，参考图2-3，正极极片2包括正极集流体21和正极材料层22。
正极材料层22包括粘结剂，基于正极材料层22的总质量计，粘结剂在正极材料层22中的质量百分含量的取值范围为0.3％～4.2％。
具体地，粘结剂在正极材料层22中的质量百分含量可以为0.3％、0.5％、1.0％、1.5％、2.0％、2.5％、3.0％、3.5％、4.0％、4.2％，或是以上任意两个数值之间的数值。
在一些实施方式中，粘结剂包括聚氨酯粘结剂，聚氨酯粘结剂具备优异的抗剪切强度和抗冲击特性，并具备优异的柔韧特性。
作为示例，正极集流体具有在其自身厚度方向相对的两个表面，正极材料层设置在正极集流体相对的两个表面的其中任意一者或两者上。
在一些实施方式中，正极集流体可采用金属箔片或复合集流体。例如，作为金属箔片，可采用铝箔。复合集流体可包括高分子材料基层和形成于高分子材料基层至少一个表面上的金属层。复合集流体可通过将金属材料(铝、铝合金、镍、镍合金、钛、钛合金、银及银合金等)形成在高分子材料基材(如聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、聚苯乙烯(PS)、聚乙烯(PE)等的基材)上而形成。
在一些实施方式中，正极材料层包括正极活性材料，正极活性材料可采用本领域公知的用于锂离子电池的正极活性材料。作为示例，正极活性材料可包括以下材料中的至少一种：橄榄石结构的含锂磷酸盐、锂过渡金属氧化物及其各自的改性化合物。但本申请并不限定于这些材料，还可以使用其他可被用作锂离子电池正极活性材料的传统材料。这些正极活性材料可以仅单独使用一种，也可以将两种以上组合使用。其中，锂过渡金属氧化物的示例可包括但不限于锂钴氧化物(如LiCoO2)、锂镍氧化物(如LiNiO2)、锂锰氧化物(如LiMnO2、LiMn2O4)、锂镍钴氧化物、锂锰钴氧化物、锂镍锰氧化物、锂镍钴锰氧化物(如LiNi1/3Co1/3Mn1/3O2(也可以简称为NCM333)、LiNi0.5Co0.2Mn0.3O2(也可以简称为NCM523)、LiNi0.5Co0.25Mn0.25O2(也可以简称为NCM211)、LiNi0.6Co0.2Mn0.2O2(也可以简称为NCM622)、LiNi0.8Co0.1Mn0.1O2(也可以简称为NCM811)、锂镍钴铝氧化物(如LiNi0.85Co0.15Al0.05O2)及其改性化合物等中的至少一种。橄榄石结构的含锂磷酸盐的示例可包括但不限于磷酸铁锂(如LiFePO4(也可以简称为LFP))、磷酸铁锂与碳的复合材料、磷酸锰锂(如LiMnPO4)、磷酸锰锂与碳的复合材料、磷酸锰铁锂、磷酸锰铁锂与碳的复合材料中的至少一种。
在一些实施方式中，粘结剂还可以包括聚偏二氟乙烯(PVDF)、聚四氟乙烯(PTFE)、偏氟乙烯-四氟乙烯-丙烯三元共聚物、偏氟乙烯-六氟丙烯-四氟乙烯三元共聚物、四氟乙烯-六氟丙烯共聚物及含氟丙烯酸酯树脂中的至少一种。
[负极极片]
负极极片包括负极集流体以及设置在负极集流体至少一个表面上的负极膜层，所述负极膜层包括负极活性材料。
作为示例，负极集流体具有在其自身厚度方向相对的两个表面，负极膜层设置在负极集流体相对的两个表面中的任意一者或两者上。
在一些实施方式中，所述负极集流体可采用金属箔片或复合集流体。例如，作为金属箔片，可以采用铜箔。复合集流体可包括高分子材料基层和形成于高分子材料基材至少一个表面上的金属层。复合集流体可通过将金属材料(铜、铜合金、镍、镍合金、钛、钛合金、银及银合金等)形成在高分子材料基材(如聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、聚苯乙烯(PS)、聚乙烯(PE)等的基材)上而形成。
在一些实施方式中，负极活性材料可采用本领域公知的用于电池的负极活性材料。作为示例，负极活性材料可包括以下材料中的至少一种：人造石墨、天然石墨、软炭、硬炭、硅基材料、锡基材料和钛酸锂等。所述硅基材料可选自单质硅、硅氧化合物、硅碳复合物、硅氮复合物以及硅合金中的至少一种。所述锡基材料可选自单质锡、锡氧化合物以及锡合金中的至少一种。但本申请并不限定于这些材料，还可以使用其他可被用作电池负极活性材料的传统材料。这些负极活性材料可以仅单独使用一种，也可以将两种以上组合使用。
在一些实施方式中，负极膜层还可选地包括粘结剂。所述粘结剂可选自丁苯橡胶(SBR)、聚丙烯酸(PAA)、聚丙烯酸钠(PAAS)、聚丙烯酰胺(PAM)、聚乙烯醇(PVA)、海藻酸钠(SA)、聚甲基丙烯酸(PMAA)及羧甲基壳聚糖(CMCS)中的至少一种。
在一些实施方式中，负极膜层还可选地包括导电剂。导电剂可选自超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的至少一种。
在一些实施方式中，负极膜层还可选地包括其他助剂，例如增稠剂(如羧甲基纤维素钠(CMC-Na))等。
在一些实施方式中，可以通过以下方式制备负极极片：将上述用于制备负极极片的组分，例如负极活性材料、导电剂、粘结剂和任意其他组分分散于溶剂(例如去离子水)中，形成负极浆料；将负极浆料涂覆在负极集流体上，经烘干、冷压等工序后，即可得到负极极片。
[电解质]
电解质在正极极片和负极极片之间起到传导离子的作用。本申请对电解质的种类没有具体的限制，可根据需求进行选择。例如，电解质可以是液态的、凝胶态的或全固态的。
在一些实施方式中，所述电解质采用电解液。所述电解液包括电解质盐和溶剂。
在一些实施方式中，电解质盐可选自六氟磷酸锂、四氟硼酸锂、高氯酸锂、六氟砷酸锂、双氟磺酰亚胺锂、双三氟甲磺酰亚胺锂、三氟甲磺酸锂、二氟磷酸锂、二氟草酸硼酸锂、二草酸硼酸锂、二氟二草酸磷酸锂及四氟草酸磷酸锂中的至少一种。
在一些实施方式中，溶剂可选自碳酸亚乙酯、碳酸亚丙酯、碳酸甲乙酯、碳酸二乙酯、碳酸二甲酯、碳酸二丙酯、碳酸甲丙酯、碳酸乙丙酯、碳酸亚丁酯、氟代碳酸亚乙酯、甲酸甲酯、乙酸甲酯、乙酸乙酯、乙酸丙酯、丙酸甲酯、丙酸乙酯、丙酸丙酯、丁酸甲酯、丁酸乙酯、1,4-丁内酯、环丁砜、二甲砜、甲乙砜及二乙砜中的至少一种。
在一些实施方式中，所述电解液还可选地包括添加剂。例如添加剂可以包括负极成膜添加剂、正极成膜添加剂，还可以包括能够改善电池某些性能的添加剂，例如改善电池过充性能的添加剂、改善电池高温或低温性能的添加剂等。
在一些实施方式中，正极极片、负极极片和隔离膜可通过卷绕工艺或叠片工艺制成电极组件。
在一些实施方式中，电池单体可包括外包装。该外包装可用于封装上述电极组件及电解液。
在一些实施方式中，电池单体的外包装可以是硬壳，例如硬塑料壳、铝壳、钢壳等。电池单体的外包装也可以是软包，例如袋式软包。软包的材质可以是塑料，作为塑料，可列举出聚丙烯、聚对苯二甲酸丁二醇酯以及聚丁二酸丁二醇酯等。
本申请对电池单体的形状没有特别的限制，其可以是圆柱形、方形或其他任意的形状。例如，图7是作为一个示例的方形结构的电池单体70。
在一些实施方式中，参照图8，外包装可包括壳体71和盖板73。其中，壳体71可包括底板和连接于底板上的侧板，底板和侧板围合形成容纳腔。壳体71具有与容纳腔连通的开口，盖板73能够盖设于所述开口，以封闭所述容纳腔。正极极片、负极极片和隔离膜可经卷绕工艺或叠片工艺形成电极组件72。电极组件72封装于容纳腔内。电解液浸润于电极组件72中。电池单体70所含电极组件72的数量可以为一个或多个，本领域技术人员可根据具体实际需求进行选择。
在一些实施方式中，电池80可以包括多个电池单体70。例如，如图9所示，为本申请一个实施例的一种电池80的结构示意图，电池80可以包括多个电池单体70。电池80还可以包括箱体81，箱体81内部为中空结构，多个电池单体70容纳于箱体81内。例如，多个电池单体70相互并联或串联或混联组合后置于箱体81内。
可选地，电池80还可以包括其他结构，在此不再一一赘述。例如，该电池80还可以包括汇流部件，汇流部件用于实现多个电池单体70之间的电连接，例如并联或串联或混联。具体地，汇流部件可通过连接电池单体70的电极端子实现电池单体70之间的电连接。进一步地，汇流部件可通过焊接固定于电池单体70的电极端子。多个电池单体70的电能可进一步通过导电机构穿过箱体81而引出。可选地，导电机构也可属于汇流部件。
根据不同的电力需求，电池单体70的数量可以设置为任意数值。多个电池单体70可通过串联、并联或混联的方式连接以实现较大的容量或功率。由于每个电池80中包括的电池单体70的数量可能较多，为了便于安装，可以将电池单体70分组设置，每组电池单体70组成电池模块。电池模块中包括的电池单体70的数量不限，可以根据需求设置。电池可以包括多个电池模块，这些电池模块可通过串联、并联或混联的方式进行连接。
另外，本申请还提供一种用电装置，该用电装置包括本申请提供的电池单体、电池模块或电池中的至少一种。电池单体、电池模块或电池可以用作该用电装置的电源，也可以用作该用电装置的能量存储单元。该用电装置可以包括移动设备(例如手机、笔记本电脑等)、电动车辆(例如纯电动车、混合动力电动车、插电式混合动力电动车、电动自行车、电动踏板车、电动高尔夫球车、电动卡车等)、电气列车、船舶及卫星、储能系统等，但不限于此。
作为该用电装置，可以根据其使用需求来选择电池单体、电池模块或电池。
图10是作为一个示例的用电装置。该用电装置为纯电动车、混合动力电动车、或插电式混合动力电动车等。为了满足该用电装置对电池单体的高功率和高能量密度的需求，可以采用电池或电池模块。
作为另一个示例的装置可以是手机、平板电脑、笔记本电脑等。该装置通常要求轻薄化，可以采用电池单体作为电源。
[实施例]
以下，说明本申请的实施例。下面描述的实施例是示例性的，仅用于解释本申请，而不能理解为对本申请的限制。实施例中未注明具体技术或条件的，按照本领域内的文献所描述的技术或条件或者按照产品说明书进行。所用试剂或仪器未注明生产厂商者，均为可以通过市购获得的常规产品。
1、正极极片的制备
正极极片1：
在反应釜中加入100.000kg的聚乙二醇(PEG，分子量为1000)，在95℃温度下干燥3h，之后向反应釜中加入18.500kg的六亚甲基二异氰酸酯，再加入2.405g的催化剂三乙胺，75℃温度下反应，反应过程中检测异氰酸酯基团(-NCO)含量，直到-NCO含量达到理论值，再向反应釜中加入1.742kg的封闭剂甲乙酮肟继续反应，反应结束后制得聚氨酯预聚体。
将97.300kg的正极活性材料磷酸铁锂(LiFePO4)，1.000kg的聚氨酯预聚体，1.400kg的导电剂乙炔黑在行星式搅拌罐中，以公转速度25r/min搅拌20min；在搅拌罐中加入53.850kg的N-甲基吡咯烷酮(NMP)溶液，以公转速度25r/min，自转速度900r/min搅拌50min；在搅拌罐中加入300.000g的分散剂聚乙烯吡咯烷酮(PVP)以及0.487kg的交联剂三乙烯四胺，以公转速度25r/min，自转速度1400r/min搅拌50min，制得正极浆料。
将上述制得的正极浆料，刮涂到涂碳铝箔上，在温度110℃下烘烤15min，制得正极极片1。
上面提到的异氰酸酯基团(-NCO)含量的检测，可以根据国家标准GB/T12009.4提供的异氰酸酯基团含量的检测方法进行检测。-NCO含量的理论值是根据实施例中聚氨酯预聚反应的反应原料的配比进行理论计算得到的理论值。
正极极片2：正极极片2与正极极片1的制备相似，不同的是，制备正极极片2的过程中，六亚甲基二异氰酸酯的添加量为20.177kg，催化剂三乙胺的添加量为2.473g，封闭剂甲乙酮肟的添加量为3.485kg，交联剂三乙烯四胺的添加量为0.975kg，制得正极极片2。
正极极片3：正极极片3与正极极片1的制备相似，不同的是，制备正极极片3的过程中，六亚甲基二异氰酸酯的添加量为21.858kg，催化剂三乙胺的添加量为2.542g，封闭剂甲乙酮肟的添加量为5.227kg，交联剂三乙烯四胺的添加量为1.462kg，制得正极极片3。
正极极片4：正极极片4与正极极片1的制备相似，不同的是，制备正极极片4的过程中，六亚甲基二异氰酸酯的添加量为23.540kg，催化剂三乙胺的添加量为2.610g，封闭剂甲乙酮肟的添加量为6.970kg，交联剂三乙烯四胺的添加量为1.950kg，制得正极极片4。
正极极片5：正极极片5与正极极片1的制备相似，不同的是，制备正极极片5的过程中，六亚甲基二异氰酸酯的添加量为25.221kg，催化剂三乙胺的添加量为 2.679g，封闭剂甲乙酮肟的添加量为8.712kg，交联剂三乙烯四胺的添加量为2.437kg，制得正极极片5。
正极极片6：正极极片6与正极极片1的制备相似，不同的是，制备正极极片6的过程中，六亚甲基二异氰酸酯的添加量为26.902kg，催化剂三乙胺的添加量为2.747g，封闭剂甲乙酮肟的添加量为10.454kg，交联剂三乙烯四胺的添加量为2.925kg，制得正极极片6。
正极极片7：正极极片7与正极极片1的制备相似，不同的是，制备正极极片7的过程中，六亚甲基二异氰酸酯的添加量为28.584kg，催化剂三乙胺的添加量为2.816g，封闭剂甲乙酮肟的添加量为12.197kg，交联剂三乙烯四胺的添加量为3.412kg，制得正极极片7。
正极极片8：正极极片8与正极极片1的制备相似，不同的是，制备正极极片8的过程中，六亚甲基二异氰酸酯的添加量为30.265kg，催化剂三乙胺的添加量为2.884g，封闭剂甲乙酮肟的添加量为13.939kg，交联剂三乙烯四胺的添加量为3.899kg，制得正极极片8。
正极极片9：正极极片9与正极极片1的制备相似，不同的是，制备正极极片9的过程中，六亚甲基二异氰酸酯的添加量为33.638kg，催化剂三乙胺的添加量为3.021g，封闭剂甲乙酮肟的添加量为17.424kg，交联剂三乙烯四胺的添加量为4.874kg，制得正极极片9。
正极极片10：正极极片10与正极极片1的制备相似，不同的是，制备正极极片10的过程中，PEG的添加量为60.000kg，还添加了40.000kg的聚丁二醇(PTMG，分子量为1000)作为聚氨酯预聚体的反应原料，六亚甲基二异氰酸酯的添加量为25.221kg，催化剂三乙胺的添加量为2.679g，封闭剂甲乙酮肟的添加量为8.712kg，交联剂三乙烯四胺的添加量为2.437kg，制得正极极片10。
正极极片11：正极极片11与正极极片1的制备相似，不同的是，制备正极极片11的过程中，PEG的添加量为60.000kg，还添加了40.000kg的聚己内酯(PCL，分子量为1000)作为聚氨酯预聚体的反应原料，六亚甲基二异氰酸酯的添加量为25.221kg，催化剂三乙胺的添加量为2.679g，封闭剂甲乙酮肟的添加量为8.712kg，交联剂三乙烯四胺的添加量为2.437kg，制得正极极片11。
正极极片12：正极极片12与正极极片1的制备相似，不同的是，制备正极极片12的过程中，PEG的添加量为60.000kg，还添加了40.000kg的聚碳酸酯二醇(PCDL，分子量为1000)作为聚氨酯预聚体的反应原料，六亚甲基二异氰酸酯的添加量为25.221kg，催化剂三乙胺的添加量为2.679g，封闭剂甲乙酮肟的添加量为8.712kg，交联剂三乙烯四胺的添加量为2.437kg，制得正极极片12。
正极极片13：正极极片13与正极极片1的制备相似，不同的是，制备正极极片13的过程中，PEG的添加量为60.000kg，还添加了40.000kg的聚丙二醇(PPG，分子量为1000)作为聚氨酯预聚体的反应原料，六亚甲基二异氰酸酯的添加量为25.221kg，催化剂三乙胺的添加量为2.679g，封闭剂甲乙酮肟的添加量为8.712kg，交联剂三乙烯四胺的添加量为2.437kg，制得正极极片13。
正极极片14：正极极片14与正极极片1的制备相似，不同的是，制备正极极片14的过程中，PEG的添加量为60.000kg，还添加了40.000kg的聚二甲基硅氧烷(PDMS，分子量为1000)作为聚氨酯预聚体的反应原料，六亚甲基二异氰酸酯的添加量为25.221kg，催化剂三乙胺的添加量为2.679g，封闭剂甲乙酮肟的添加量为8.712kg，交联剂三乙烯四胺的添加量为2.437kg，制得正极极片14。
正极极片15：正极极片15与正极极片1的制备相似，不同的是，制备正极极片15的过程中，PEG的添加量为60.000kg，还添加了40.000kg的聚乳酸-羟基乙酸共聚物(PLGA，分子量为1000)作为聚氨酯预聚体的反应原料，六亚甲基二异氰酸酯的添加量为25.221kg，催化剂三乙胺的添加量为2.679g，封闭剂甲乙酮肟的添加量为8.712kg，交联剂三乙烯四胺的添加量为2.437kg，制得正极极片15。
正极极片16：在反应釜中加入100.000kg的聚乙二醇(PEG，分子量为1000)，在95℃温度下干燥3h，之后向反应釜中加入25.221kg的六亚甲基二异氰酸酯，再加入2.679g的催化剂三乙胺，以及0.487kg的交联剂三乙烯四胺，115℃温度下反应，制得聚氨酯粘结剂。
将97.300kg的正极活性材料LiFePO4，1.000kg的聚氨酯粘结剂，1.400kg的导电剂乙炔黑在行星式搅拌罐中，以公转速度25r/min搅拌20min；在搅拌罐中加入53.850kg的NMP溶液，以公转速度25r/min，自转速度900r/min搅拌50min；在搅拌罐中加入300.000g的分散剂PVP以公转速度25r/min，自转速度1400r/min搅拌50min，制得正极浆料。
将上述制得的正极浆料，刮涂到涂碳铝箔上，在温度110℃下烘烤15min，制得正极极片16。
正极极片17：将3.97kg的正极活性材料LiFePO4，16.4g的粘结剂聚偏氟乙烯，57.4g的导电剂乙炔黑在行星式搅拌罐中，公转转速25r/min，搅拌20min。在搅拌罐中加入2.4kg的NMP溶液，公转速度25r/min，自转速度900r/min，搅拌50min。在搅拌罐中加入12.3g分散剂PVP，以公转速度25r/min，自转速度1400r/min，搅拌50min，制得正极浆料。
将上述制得的正极浆料，刮涂到涂碳铝箔上面，110℃烘烤15min，制得正极极片17。
根据本申请实施例提供的正极极片的制备方法制得的正极极片，将制得的正极极片中的烘干的正极浆料从正极集流体上刮涂下来，用NMP溶液溶解，其中的聚氨酯由于分子量很大，不可复溶，在溶剂中仍为固体状。
2、电池单体的制备
[实施例1]
(1)正极极片
正极极片采用上述制备的正极极片1。
(2)负极极片的制备
将人造石墨、导电炭黑、丁苯橡胶(SBR)、CMC按照重量比为95.5:1.2:1.3:1.5溶于溶剂去离子水中，均匀混合后制备成负极浆料；然后将负极浆料均匀涂布在负极集流体上，烘干后得到负极膜片，再经过冷压、分切得到负极极片。
(3)电解液的制备
在含水量<10ppm的氩气气氛手套箱中，将充分干燥的锂盐(LiPF6)溶解在体积比为20:20:60的碳酸乙烯酯(EC)、碳酸甲乙酯(EMC)和碳酸二乙酯(DEC)的混合溶剂中，然后加入添加剂碳酸亚乙烯酯(VC)，混合均匀，获得电解液。其中，锂盐的浓度为1mol/L。
(4)隔离膜的制备
以常规的聚丙烯膜作为隔离膜。
(5)锂离子电池的组装
将正极极片、隔离膜、负极极片按顺序叠好，使隔离膜处于正极极片和负极极片之间起到隔离的作用，然后卷绕得到电极组件；将电极组件置于电池壳体中，干燥后注入电解液，再经过化成、静置等工艺制得锂离子电池1，作为实施例1。
[实施例2-15，对比例1-2]
实施例2-15和对比例1-2的锂离子电池与实施例1的锂离子电池的制备方法相似，不同点在于使用了不同的正极极片(其中，实施例1-15采用的是正极极片1-15，对比例1-2采用的是正极极片16-17)，具体详见表1。
3、正极极片的性能测试
(1)正极极片中的粘结剂的粘结力测试
参考国标《胶粘剂180°剥离强度实验方法》，用刀片截取宽度为30mm，长度为100-160mm的正极极片，将专用双面胶贴于钢板上，双面胶宽度为20mm，长度90-150mm。将截取的正极极片贴在双面胶上，测试面朝下，后用压辊沿同一个方向滚压三次。
将宽度与正极极片等宽，长度大于正极极片长度80-200mm的纸带插入正极极片下方，并且用皱纹胶固定。
打开三思拉力机电源(灵敏度为1N)，指示灯亮，调整限位块到合适位置，将钢板未贴正极极片的一端用下夹具固定。将纸带向上翻折，用上夹具固定，利用拉力机附带的手动控制器上的“上行”和“下行”按钮调整上夹具的位置。然后进行测试并读取数值。
(2)正极极片的膜片电阻测试
将制备的正极极片，采用四探针电阻仪进行测试，每个样品测试三个平行样，取平均值。
4、电池性能测试
(1)初始直流电阻(Directive Current Resistance，DCR)测试
在常温下，将各实施例和对比例的电池以0.5C恒流充电到3.65V，再恒压充电至电流为0.05C；将电池以0.5C恒流放电60分钟，以调整电池至50％SOC，此时电池的电压记为U1；将电池以4C恒流放电30秒，采用0.1秒采点，放电末期电压记为U2。用电池50％SOC时的放电DCR表示电池的初始DCR，电池的初始DCR＝(U1-U2)/4C。
(2)电池容量保持率测试
在25℃下，将锂离子电池以1/3C恒流充电至3.65V，然后以3.65V恒压充电至电流为0.05C，搁置5min，再以1/3C放电至2.5V，所得容量记为初始容量C0。重复以上步骤，并同时记录循环第n次后电池的放电容量Cn，则循环n次后电池容量保持率(％)＝(Cn/C0)×100％。
比如，锂离子电池25℃循环500次后的容量保持率(％)＝(第500次循环的放电容量/首次循环的放电容量)×100％。
不同实施例和对比例的产品参数，以及按照上述方法分别对制备得到的正极极片1-17进行性能测试的测试结果，请参见表1。表1中的聚氨酯预聚体的R值指的是聚氨酯预聚体中的异氰酸根与羟基的摩尔比值为R。按照上述方法分别对制备得到的对比例1-2、实施例1-15进行电池性能测试的测试结果，请参见表2。
表1：实施例和对比例的产品参数及正极极片1-17的性能测试结果
表2：实施例1-15及对比例1-2的的性能测试结果
从对比例1-2和实施例1-15的结果比较可知，在正极极片的制备中，正极浆料中包含有聚氨酯预聚体，制得的正极极片的粘结力较好，正极极片的膜片电阻也较小。对应的锂离子电池的DCR较小，锂离子电池的容量保持率较好。
从实施例1-9的结果比较可知，控制聚氨酯预聚体的预聚反应的反应原料PEG和六亚甲基二异氰酸酯的配比，从而控制聚氨酯预聚体中的异氰酸根与羟基的摩尔比值R，且将R设置在适宜范围内，正极极片的性能以及锂离子电池的性能较好。本申请中，在其他条件一定的情况下，控制聚氨酯预聚体中的异氰酸根与羟基的摩尔比值R在1.2～1.8范围内，正极极片的粘结力较好，正极极片的膜片电阻也较小；对应的锂离子电池的DCR较小，锂离子电池的容量保持率较好。
虽然已经参考优选实施例对本申请进行了描述，但在不脱离本申请的范围的情况下，可以对其进行各种改进并且可以用等效物替换其中的部件。尤其是，只要不存在结构冲突，各个实施例中所提到的各项技术特征均可以任意方式组合起来。本申请并不局限于文中公开的特定实施例，而是包括落入权利要求的范围内的所有技术方案。

Claims (23)

  1. 一种正极极片的制备方法，包括：
    制备正极浆料，其中，所述正极浆料包括聚氨酯预聚体；
    将所述正极浆料涂覆于正极集流体的至少一侧；
    将涂覆于所述正极集流体的至少一侧的所述正极浆料烘干，制得所述正极极片。
  2. 根据权利要求1所述的制备方法，其特征在于，所述正极浆料的烘干温度的取值范围为60℃～150℃，可选地，所述烘干温度的取值范围为80℃～140℃。
  3. 根据权利要求1或2所述的制备方法，其特征在于，所述制备正极浆料包括：
    制备粘结剂前驱体溶液；
    在所述粘结剂前驱体溶液中加入正极活性材料、导电剂、分散剂和交联剂，混合，制得所述正极浆料。
  4. 根据权利要求3所述的制备方法，其特征在于，所述导电剂包括导电炭、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的至少一种。
  5. 根据权利要求3或4所述的制备方法，其特征在于，所述分散剂包括聚乙烯吡咯烷酮。
  6. 根据权利要求3至5中任一项所述的制备方法，其特征在于，所述交联剂包括蔗糖、二乙烯三胺、三乙烯四胺、四乙烯五胺、二乙基甲苯二胺、二甲硫基甲苯二胺、三臂聚己内酯、四臂聚己内酯中的至少一种。
  7. 根据权利要求3至6中任一项所述的制备方法，其特征在于，所述制备粘结剂前驱体溶液包括：
    制备所述聚氨酯预聚体；
    将所述聚氨酯预聚体分散于N-甲基吡咯烷酮溶剂，制得所述粘结剂前驱体溶液。
  8. 根据权利要求7所述的制备方法，其特征在于，所述制备所述聚氨酯预聚体包括：
    干燥聚醚多元醇，和/或，聚酯多元醇；
    将干燥后的所述聚醚多元醇，和/或，所述聚酯多元醇与异氰酸酯和催化剂混合，进行预聚反应；
    所述预聚反应结束后，向反应产物中加入封闭剂，制得所述聚氨酯预聚体。
  9. 根据权利要求8所述的制备方法，其特征在于，所述聚醚多元醇，和/或，所述聚酯多元醇的干燥温度的取值范围为90℃～95℃，干燥时间的取值范围为2～3小时。
  10. 根据权利要求8或9所述的制备方法，其特征在于，所述异氰酸酯包括二异氰酸酯，可选地，所述二异氰酸酯包括芳香族二异氰酸酯、脂肪族二异氰酸酯中的至少一种。
  11. 根据权利要求8至10中任一项所述的制备方法，其特征在于，所述异氰酸酯包括异甲苯-2,3-二异氰酸酯、甲苯-2,4-二异氰酸酯、甲苯-2,5-二异氰酸酯、甲苯-2,6-二异氰酸酯、甲苯-3,4-二异氰酸酯、甲苯-3,5-二异氰酸酯、1,5-萘二异氰酸酯、对苯二异氰酸酯、间苯二异氰酸酯、六亚甲基二异氰酸酯、五亚甲基二异氰酸酯、L-赖氨酸乙酯二异氰酸酯、氢化甲苯二异氰酸酯、异佛尔酮二异氰酸酯、二苯基甲烷二异氰酸酯、氢化二苯基甲烷二异氰酸酯中的至少一种。
  12. 根据权利要求8至11中任一项所述的制备方法，其特征在于，所述聚氨酯预聚体中的异氰酸根与羟基的摩尔比值R的取值范围为1.1～2.0，可选地，R的取值范围为1.2～1.8。
  13. 根据权利要求8至12中任一项所述的制备方法，其特征在于，所述聚醚多元醇包括聚乙二醇、聚环氧丙烷二醇、聚环氧乙烷二醇、聚四氢呋喃醚二醇、聚乙二醇-丙二醇共聚物中的至少一种。
  14. 根据权利要求8至13中任一项所述的制备方法，其特征在于，所述聚酯多元醇包括聚己内酯、聚碳酸酯二醇、聚乳酸二醇、聚乙交酯-丙交酯共聚物中的至少一种。
  15. 根据权利要求8至14中任一项所述的制备方法，其特征在于，所述催化剂包括有机锡类催化剂、有机铋类催化剂、叔胺类催化剂中的至少一种。
  16. 根据权利要求8至15中任一项所述的制备方法，其特征在于，所述催化剂包括二丁基锡二月桂酸酯、辛酸亚锡、N-乙基吗啉、N-甲基吗啉、三乙胺中的至少一种。
  17. 根据权利要求8至16中任一项所述的制备方法，其特征在于，所述封闭剂包括三氯乙醇、三氟乙醇、十二烷基硫醇、三苯基硫醇、己硫醇、N,N-丁二醇乙酰胺、乙二醇单己醚、N,N-二醇酰胺、苯酚、吡啶、甲乙酮肟、己内酰胺、乙酰乙酸乙酯中的至少一种。
  18. 根据权利要求8至17中任一项所述的制备方法，其特征在于，基于所述预聚反应的反应原料的总质量计，所述催化剂在所述预聚反应的反应原料中的质量百分含量的取值范围为0.001％～1.0％。
  19. 一种根据权利要求1至18中任一项所述的制备方法制得的正极极片。
  20. 根据权利要求19所述的正极极片，其特征在于，所述正极极片包括正极材料层，基于所述正极材料层的总质量计，所述正极材料层中的粘结剂在所述正极材料层中的质量百分含量的取值范围为0.3％～4.2％。
  21. 一种电池单体，包括根据权利要求19或20所述的正极极片。
  22. 一种电池，包括根据权利要求21所述的电池单体。
  23. 一种用电装置，包括根据权利要求22所述的电池。
PCT/CN2024/071053 2023-06-21 2024-01-08 正极极片的制备方法、正极极片、电池单体、电池和用电装置 Ceased WO2024259956A1 (zh)

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