WO2024045472A1 - 分散剂、粘结剂组合物、正极浆料、二次电池、电池模块、电池包及用电装置 - Google Patents

分散剂、粘结剂组合物、正极浆料、二次电池、电池模块、电池包及用电装置 Download PDF

Info

Publication number
WO2024045472A1
WO2024045472A1 PCT/CN2023/071658 CN2023071658W WO2024045472A1 WO 2024045472 A1 WO2024045472 A1 WO 2024045472A1 CN 2023071658 W CN2023071658 W CN 2023071658W WO 2024045472 A1 WO2024045472 A1 WO 2024045472A1
Authority
WO
WIPO (PCT)
Prior art keywords
positive electrode
dispersant
battery
slurry
fluoropolymer
Prior art date
Application number
PCT/CN2023/071658
Other languages
English (en)
French (fr)
Inventor
李�诚
曾子鹏
刘会会
王景明
Original Assignee
宁德时代新能源科技股份有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 宁德时代新能源科技股份有限公司 filed Critical 宁德时代新能源科技股份有限公司
Publication of WO2024045472A1 publication Critical patent/WO2024045472A1/zh

Links

Images

Classifications

    • 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
    • H01M4/623—Binders being polymers fluorinated 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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/054—Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
    • 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
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • 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
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present application relates to the technical field of secondary batteries, and in particular to a fluoropolymer, its preparation method and use, secondary batteries, battery modules, battery packs and electrical devices.
  • secondary batteries are widely used in energy storage power systems such as hydraulic, thermal, wind and solar power stations, as well as power tools, electric bicycles, electric motorcycles, electric vehicles, Military equipment, aerospace and other fields.
  • the present application was made in view of the above-mentioned problems, and its purpose is to provide a dispersant that can enhance the dispersibility of slurry and improve the stability of slurry.
  • the first aspect of the application provides a dispersant
  • the dispersant is a fluoropolymer containing the structural unit shown in formula I, and the weight average molecular weight of the fluoropolymer is less than or equal to 20,000, Optional range is 5,000 to 20,000.
  • R 1 and R 2 are each independently selected from hydrogen, fluorine, chlorine or trifluoromethyl.
  • the dispersant provided by this application uses a fluoropolymer with a weight average molecular weight of less than or equal to 20,000 and containing structural units of Formula I to improve the fluidity and filterability of the positive electrode slurry, improve the stability and processability of the slurry, and at the same time
  • the addition of the fluoropolymer will not cause a significant decrease in the bonding performance of the electrode piece like traditional dispersants, and will help reduce the growth rate of DC impedance during battery cycling.
  • R 1 is selected from hydrogen, fluoro, or trifluoromethyl
  • R 2 is selected from hydrogen, fluoro, chlorine, or trifluoromethyl
  • R 1 is selected from hydrogen, fluoro, chlorine, or trifluoromethyl
  • R 2 is selected from hydrogen, fluorine or trifluoromethyl.
  • the fluoropolymer has a weight average molecular weight of 0.5,000 to 20,000.
  • the polymer containing the structural unit represented by Formula I is a fluorocarbon polymer, selected from the copolymers of polytetrafluoroethylene, polyvinylidene fluoride, vinylidene fluoride and hexafluoropropylene. of one or more.
  • the above-mentioned polymers with a weight average molecular weight of less than or equal to 20,000 have good adhesion to the positive electrode active material, significantly improving the dispersion performance of the slurry, so that the positive electrode active material can be dispersed on the surface of the electrode piece Evenly distributed.
  • the fluoropolymer particles have a median diameter Dv50 of 0.5 to 1 ⁇ m. Polymer particles within this particle size range are beneficial to the dissolution of the polymer in the positive electrode slurry solvent, such as N-methylpyrrolidone, and reduce the processing difficulty of the glue solution.
  • the fluoropolymer is dissolved in N-methylpyrrolidone to prepare a glue solution.
  • the viscosity of the glue solution is 20 ⁇ 50mPa ⁇ s. Polymers within this viscosity range help the fluoropolymer fully adhere to the positive active material, reduce the agglomeration of the positive active material and blockage of the filter, improve the dispersion performance of the slurry and help improve the solid content of the slurry. content.
  • a second aspect of the present application also provides a binder composition, including a binder and a dispersant in any embodiment of the present application.
  • the binder is polyvinylidene fluoride or its modified polymer with a weight average molecular weight of 700,000 to 1.1 million.
  • Controlling the weight average molecular weight of the binder can further reduce the cycle internal resistance growth rate of the battery while improving the stability, processability and bonding strength of the positive electrode slurry.
  • the mass ratio of the dispersant and the binder is 1:80 ⁇ 1:2.
  • the mass ratio of the dispersant and the binder is 1:40 ⁇ 1:4.
  • the second aspect of the application also provides a method for preparing fluorine-containing polymers, which method includes: providing at least one monomer represented by formula II,
  • R 1 and R 2 are each independently selected from one or more types of hydrogen, fluorine, chlorine, and trifluoromethyl;
  • the monomer is polymerized under polymerizable conditions to prepare a polymer.
  • the weight average molecular weight of the polymer is less than or equal to 20,000, and can be selected from 0.5 million to 20,000.
  • the prepared fluoropolymer has a lower weight average molecular weight and viscosity, has good adhesion with the cathode active material, and avoids the cathode active material, such as phosphoric acid, through the steric hindrance of the polymer.
  • the agglomeration between lithium iron (LFP) powder particles increases the stability of the slurry.
  • the preparation method further includes the following steps:
  • reaction solvent and dispersion aid to the container, and fill the container with non-reactive gas;
  • the polymer containing the structural unit represented by Formula I provided in the first aspect of the application can be obtained.
  • the preparation method has low raw material cost and relatively mild reaction conditions, which is conducive to the mass production of fluoropolymers.
  • a third aspect of the present application provides a cathode slurry that includes the binder composition in any embodiment.
  • the positive electrode slurry improves the adhesion to the positive electrode active material and reduces the agglomeration of the positive electrode active material powder, significantly improving the dispersion and stability of the positive electrode slurry.
  • the properties and processability are beneficial to the preparation of high-pressure, dense, and high-area density cathode sheets.
  • the viscosity of the positive electrode slurry is 2000-50000 mPa ⁇ s, optionally 2500-47000 mPa ⁇ s.
  • the fluidity and filterability of the cathode slurry within the viscosity range are significantly improved, and the stability and processability of the cathode slurry are improved.
  • the mass content of the dispersant is 0.05% to 0.7%, optionally 0.1% to 0.6%, based on the total mass of solid matter in the cathode slurry.
  • the use of this mass content of fluoropolymer in the cathode slurry helps to improve the fluidity, filterability and viscosity of the cathode slurry, and can reduce the DC impedance growth rate of the pole piece.
  • the mass content of the binder in the cathode slurry is 1.4% to 4%, optionally 1.6% to 3.9%, based on the total mass of solid matter in the cathode slurry.
  • the mass content of the binder within this range helps the adhesion and bonding between solid substances in the positive electrode slurry, stably connects the positive active material and the conductive agent, ensures the integrity of the electrode piece, and effectively prevents positive electrode activity
  • the direct contact between the material and the electrolyte reduces the occurrence of side reactions and suppresses the increase in DC impedance.
  • the cathode slurry contains a cathode active material, which is a lithium-containing transition metal oxide, optionally lithium iron phosphate or lithium nickel cobalt manganese oxide, or doping modifications thereof materials, or at least one of their conductive carbon coating modified materials, conductive metal coating modified materials, or conductive polymer coating modified materials.
  • a cathode active material which is a lithium-containing transition metal oxide, optionally lithium iron phosphate or lithium nickel cobalt manganese oxide, or doping modifications thereof materials, or at least one of their conductive carbon coating modified materials, conductive metal coating modified materials, or conductive polymer coating modified materials.
  • the fourth aspect of the present application provides the use of the dispersant described in the first aspect or the dispersant prepared by the method described in the third aspect in secondary batteries.
  • the fluoropolymer By using the fluoropolymer, the phenomenon of uneven dispersion of positive electrode active materials such as agglomeration and clogging of filters in the positive electrode slurry can be significantly improved, and the fluidity, filterability and processability of the positive electrode slurry can be improved. Dispersion and/or suspension in solvent improves the stability of the slurry.
  • the fifth aspect of the present application provides a secondary battery, including the fluorine-containing polymer provided in the first aspect of the present application or the positive electrode active material prepared according to the method of the second aspect of the present application or the positive electrode active material provided according to the third aspect of the present application. Materials, positive electrode plates, separators, negative electrode plates and electrolytes.
  • the secondary battery is a lithium-ion battery or a sodium-ion battery.
  • a sixth aspect of the present application provides a battery module including the secondary battery of the fifth aspect of the present application.
  • a seventh aspect of the present application provides a battery pack, including the battery module of the sixth aspect of the present application.
  • An eighth aspect of the present application provides an electrical device, including at least one selected from the secondary battery of the fifth aspect of the present application, the battery module of the sixth aspect of the present application, or the battery pack of the seventh aspect of the present application. kind.
  • Figure 1 is a schematic diagram of a secondary battery according to an embodiment of the present application.
  • Figure 2 is an exploded view of the secondary battery according to an embodiment of the present application shown in Figure 1;
  • FIG. 3 is a schematic diagram of a battery module according to an embodiment of the present application.
  • Figure 4 is a schematic diagram of a battery pack according to an embodiment of the present application.
  • FIG 5 is an exploded view of the battery pack according to an embodiment of the present application shown in Figure 4;
  • FIG. 6 is a schematic diagram of a power consumption device using a secondary battery as a power source according to an embodiment of the present application.
  • Ranges disclosed herein are defined in terms of lower and upper limits. A given range is defined by selecting a lower limit and an upper limit that define the boundaries of the particular range. Ranges defined in this manner may be inclusive or exclusive of the endpoints, and may be arbitrarily combined, that is, 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, understand that ranges of 60-110 and 80-120 are also expected. Furthermore, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2- 3, 2-4 and 2-5.
  • the numerical range “a-b” represents an abbreviated representation of any combination of real numbers 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 article, and "0-5" is just an abbreviation of these numerical combinations.
  • a certain parameter is an integer ⁇ 2
  • 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.
  • step (c) means that step (c) may be added to the method in any order.
  • the method may include steps (a), (b) and (c). , may also include steps (a), (c) and (b), may also include steps (c), (a) and (b), etc.
  • condition "A or B” is satisfied by any of the following conditions: 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).
  • the new generation of cathode active materials has received widespread attention from the industry due to its low cost, high performance and safety. However, they often have characteristics such as large specific surface area, small particle size, large amount of carbon element coating on the surface after carbon coating, high degree of graphitization and microporous structure, etc., resulting in the stability of the new generation cathode active materials in the slurry.
  • the slurry has poor dispersion and is prone to agglomeration and clogging of filters during the pulping process.
  • the slurry has poor dispersion, is easy to precipitate, has high viscosity and low solid content, and the surface of the pole piece prepared by it is prone to cracking, peeling, particle scratches, etc. There are defects such as pinholes, and the positive active material in the pole piece is unevenly distributed and the quality of the pole piece is uneven.
  • a dispersant which is a fluoropolymer containing a structural unit represented by formula I,
  • R 1 and R 2 are each independently selected from hydrogen (H), fluorine (F), chlorine (Cl) or trifluoromethyl (-CF 3 ).
  • the term "dispersant” refers to a chemical compound, polymer or mixture that promotes uniform dispersion of material particles in a colloidal solution or colloidal dispersion.
  • polymer includes on the one hand an assembly of macromolecules that are chemically homogeneous but differ in degree of polymerization, molar mass and chain length, prepared by polymerization reactions.
  • the term on the other hand also includes derivatives of aggregates of macromolecules formed by polymerization reactions which are obtainable by reaction, for example addition or substitution, of functional groups in said macromolecules and which may be chemically homogeneous or chemically A non-homogeneous compound or mixture.
  • the fluoropolymer is used in battery slurry as a dispersing polymer to improve the dispersion of the slurry. In some embodiments, the fluoropolymer is used in battery cathode slurry to improve the dispersion of the cathode slurry. In some embodiments, the fluoropolymer is used in battery negative electrode slurry to improve the dispersion of the negative electrode slurry.
  • positive electrode also refers to the "cathode” in a battery.
  • negative electrode also refers to the "anode” in a battery.
  • R 1 is selected from hydrogen, fluoro, or trifluoromethyl
  • R 2 is selected from hydrogen, fluoro, chlorine, or trifluoromethyl
  • R 1 is selected from hydrogen, fluoro, chlorine, or trifluoromethyl
  • R 2 is selected from hydrogen, fluorine or trifluoromethyl
  • the fluoropolymer is a fluorocarbon polymer, selected from one or more copolymers of polytetrafluoroethylene, polyvinylidene fluoride, vinylidene fluoride, and hexafluoropropylene. .
  • fluorohydrocarbon polymer refers to a polymer formed by the polymerization of fluorine-substituted unsaturated hydrocarbon monomers.
  • the weight average molecular weight of the fluoropolymer is less than or equal to 20,000, and may range from 0.5 million to 20,000.
  • weight average molecular weight refers to the sum of the weight fractions of molecules of different molecular weights in the polymer multiplied by their corresponding molecular weights.
  • the weight average molecular weight of the polymer containing the structural unit shown in formula I is less than or equal to 20,000, the intermolecular force is relatively small, the adhesion and wetting properties are good, and the positive electrode can be adhered well.
  • the cathode active material in the slurry prevents/reduces aggregation between cathode active materials; at the same time, polymers with a weight average molecular weight of no more than 20,000 are in the solvent (or dispersion medium) of the cathode slurry through electrostatic repulsion or steric hindrance.
  • the fluoropolymer has highly polar fluorine functional groups. The addition of the fluoropolymer will not cause a significant decrease in the bonding performance of the electrode piece like traditional dispersants, which is conducive to improving the overall performance of the battery.
  • polymers containing structural units represented by Formula I are soluble in oily solvents.
  • polymers containing structural units represented by Formula I can be dissolved in aqueous solvents.
  • Exemplary oily solvents include dimethylacetamide, N,N-dimethylformamide, N-methylpyrrolidone, acetone, and dimethyl carbonate.
  • Examples of aqueous solvents include, but are not limited to, water.
  • the particles of fluoropolymer have a median diameter Dv50 of 0.5 to 1 ⁇ m. In some embodiments, the particles of the fluoropolymer have a median diameter Dv50 of 0.5 to 0.8 ⁇ m, or 0.8 to 1 ⁇ m, or 0.6 to 0.9 ⁇ m. Polymer particles within this particle size range are beneficial to the dissolution of the polymer in the positive electrode slurry solvent, such as N-methylpyrrolidone, reducing the processing difficulty of the glue and improving the processing efficiency of the electrode piece.
  • the positive electrode slurry solvent such as N-methylpyrrolidone
  • the term “median particle size Dv50” refers to the particle size corresponding to when the cumulative particle size distribution percentage of the measured sample reaches 50%.
  • the viscosity of the glue prepared by dissolving the polymer in N-methylpyrrolidone is 20-50 mPa ⁇ s, and the mass percentage of the polymer in the glue is 7 %. In some embodiments, the viscosity of the glue prepared by dissolving the polymer in N-methylpyrrolidone is 20 to 45 mPa ⁇ s, or 20 to 40 mPa ⁇ s, or 20 to 35 mPa ⁇ s, or 25 ⁇ 50mPa ⁇ s, or 30 ⁇ 50mPa ⁇ s, or 35 ⁇ 50mPa ⁇ s, or 40 ⁇ 50mPa ⁇ s.
  • polymers in this viscosity range help the fluoropolymer fully adhere to the positive active material, reduce the agglomeration of the positive active material and block the filter, improve the dispersion performance of the slurry and help improve the slurry solid content. It has good adhesion with the positive active material, significantly improves the dispersion performance of the slurry, and makes the positive active material evenly distributed on the surface of the pole piece.
  • the present application also provides a method for preparing the above-mentioned dispersant, which is a fluoropolymer.
  • the method includes: providing at least one monomer represented by Formula II,
  • R 1 and R 2 are each independently selected from one or more types of hydrogen, fluorine, chlorine, and trifluoromethyl;
  • the monomer is polymerized under polymerizable conditions to prepare a fluoropolymer, and the weight average molecular weight of the fluoropolymer is less than or equal to 20,000.
  • the weight average molecular weight of the fluoropolymer ranges from 0,500 to 20,000.
  • polymerizable conditions refers to those conditions including temperature, pressure, reactant concentration, optional solvent/diluent, reactant mixing/addition parameters selected by one skilled in the art to facilitate a or other conditions for the reaction of multiple monomers in at least one polymerization reactor.
  • the preparation method further includes the following steps:
  • non-reactive gas refers to a gas that does not participate in the polymerization reaction.
  • exemplary non-reactive gases include any or a combination of argon, helium, and nitrogen.
  • normal pressure refers to a standard atmospheric pressure, which is 101KPa.
  • the reaction temperature is 65°C to 80°C, 70°C to 80°C, or 66°C to 80°C, 68°C to 80°C, 73°C to 80°C, 65°C to 75°C, or 66°C to 73°C. .
  • the reaction time is 2 hours to 4 hours, 1 hour to 3 hours, or 2 hours to 3 hours.
  • reaction solvent and dispersion aid to the container, and fill the container with non-reactive gas;
  • initiator refers to a substance that initiates the polymerization of monomers during a polymerization reaction.
  • exemplary initiators are 2-ethyl peroxydicarbonate, peroxytert-amyl pivalate.
  • pH adjuster refers to a substance that changes the pH of a solution or dispersion medium, including increasing the acidity or increasing the alkalinity.
  • exemplary pH adjusting agents include sodium bicarbonate, sodium carbonate and sodium hydroxide.
  • dispersing aid refers to substances that can promote the uniform dispersion of monomers in the medium during synthesis reactions.
  • exemplary dispersing aids include carboxyethyl cellulose ether.
  • the reaction solvent is water, which is beneficial to reducing harm to the environment.
  • the pH is adjusted to 6.5, 6.8 or 7.
  • the stirring time is 30 minutes to 55 minutes, 30 minutes to 50 minutes, 30 minutes to 45 minutes, 35 minutes to 60 minutes, 40 minutes to 60 minutes or 45 minutes to 60 minutes.
  • a polymer containing the structural unit represented by Formula I with a weight average molecular weight of less than or equal to 20,000 can be obtained.
  • the prepared fluoropolymer has a suitable weight average molecular weight and viscosity, has good adhesion with the positive active material, and significantly improves the dispersion and stability of the slurry.
  • the preparation method has wide sources of raw materials, low cost, mild reaction conditions, less harm to the environment, and is conducive to the mass production of fluorine-containing polymers.
  • This application proposes a positive electrode slurry, which includes a positive electrode active material, a conductive agent, a binder and the dispersant mentioned above in this application.
  • the positive electrode slurry improves the adhesion to the positive electrode active material and reduces the agglomeration of the positive electrode active material powder, significantly improving the dispersion, stability and processability of the positive electrode slurry, which is beneficial to Preparation of high-pressure, high-area-density positive electrode sheets.
  • N-methylpyrrolidone is used to prepare the cathode slurry.
  • the viscosity of the positive electrode slurry is 2000-50000 mPa ⁇ s.
  • the viscosity of the positive electrode slurry is 2500-47000 mPa ⁇ s, 2700-44000 mPa ⁇ s, 2500-33000 mPa ⁇ s. s, 2500 ⁇ 32000mPa ⁇ s or 2500 ⁇ 33000mPa ⁇ s.
  • the solid content of the positive electrode slurry in N-methylpyrrolidone is 58% and the viscosity of the positive electrode slurry is higher than 50000 mPa ⁇ s, although the bonding force of the pole piece may be improved, the fluidity and filtration performance of the slurry will be reduced. will decrease, causing the positive active material in the slurry to be unevenly distributed, which not only affects the processing performance of the pole piece, but also causes cracks, particle scratches, pinholes and other defects on the surface of the prepared pole piece, affecting the quality of the pole piece.
  • the solid content of the positive electrode slurry in N-methylpyrrolidone is 58% and the viscosity of the positive electrode slurry is lower than 2000 mPa ⁇ s, although the fluidity and filtration performance of the pole piece are significantly improved, the adhesion of the pole piece is serious. Reduced, the surface of the pole piece is prone to peeling defects, seriously endangering the safety of the battery using the pole piece.
  • the fluidity and filterability of the cathode slurry within the above set viscosity range are significantly improved, which makes the cathode active material evenly distributed and improves the stability and processability of the cathode slurry; in turn, it is beneficial to reduce the electronic resistance of the electrode piece and reduce the The DC impedance growth rate improves the quality of the pole piece.
  • the mass ratio of the dispersant and the binder is 1:80 ⁇ 1:2.
  • the mass ratio of the dispersant to the binder is 1:40 ⁇ 1:4, 1:20 ⁇ 1:4, 1:10 ⁇ 1:4, 1:40 ⁇ 1: 10 or 1:40 ⁇ 1:20.
  • the mass ratio of the fluoropolymer to the binder is lower than 1:80, the content of the fluoropolymer is too low and cannot fully cover the cathode active material in the cathode slurry, which is not conducive to cathode activity.
  • the dispersion of materials can easily cause the positive electrode slurry powder to agglomerate and block the filter, affecting the stability of the positive electrode slurry and the processability of the pole pieces, resulting in an increase in film resistance.
  • the mass ratio of the fluoropolymer to the binder is higher than 1:2, the fluoropolymer cannot bind a sufficient amount of conductive agent to the positive active material due to the high content of the fluoropolymer.
  • the adhesive force of the electrode pieces is small, and it is easy for demoulding to occur during processing or the positive electrode active material diffuses into the negative electrode during long-term recycling of the battery, causing great safety risks.
  • the mass ratio of the dispersant and the binder within an appropriate range can ensure sufficient coating of the positive active material and the fluoropolymer, and promote the uniform dispersion of the positive active material in the binder through good adhesion. Improve the stability and processability of cathode slurry.
  • the mass content of the dispersant is 0.05% to 0.7%, based on the total mass of solid matter in the cathode slurry.
  • the mass content of the dispersant is 0.05% to 0.6%, 0.05% to 0.5%, 0.05% to 0.4%, 0.05% to 0.3%, 0.1% to 0.7%, 0.2% to 0.7%, 0.3% to 0.7%, 0.2% to 0.6% or 0.3% to 0.6%, based on the total mass of solid matter in the positive electrode slurry.
  • the mass content of the dispersant is less than 0.05%, it is also not conducive to the dispersion of the positive electrode active materials, and it is easy to cause the positive electrode slurry powder to agglomerate, block the filter, etc., affecting the stability of the positive electrode slurry and the processability of the pole piece. , causing the film layer resistance to increase.
  • the content of the fluoropolymer is higher than 0.7%, similarly, the adhesive force of the electrode piece is small, and it is easy to demoulding during processing or the positive electrode active material diffuses into the negative electrode during long-term recycling of the battery. , causing great safety hazards.
  • the use of fluoropolymers with this mass content range in the cathode slurry can help improve the fluidity, filterability and viscosity of the cathode slurry, and can reduce the DC impedance growth rate of the pole piece.
  • the mass content of the binder in the cathode slurry is 1.4% to 4%, based on the total mass of solid matter in the cathode slurry.
  • the mass content of the binder in the positive electrode slurry is 3.3% to 3.9%, 3.4% to 3.9%, 3.5% to 3.9%, 3.6% to 3.9%, 3.7% to 3.9% , 1.6% to 1.95%, 1.6% to 1.8%, 1.6% to 1.7%, 1.6% to 3.9%, 1.6% to 3.8%, 1.6% to 3.7%, 1.6% to 3.6%, 1.6% to 3.5%, 1.6 % to 3.4% or 1.6% to 3.3%, based on the total mass of solid matter in the positive electrode slurry.
  • the binder content When the binder content is too low, the binder cannot bond a sufficient amount of conductive agent and cathode active material together.
  • the adhesive force of the electrode piece is small, and demoulding is prone to occur during processing; if the content is too low, it will also cause As a result, the binder cannot form a tight adhesion on the surface of the positive active material, and the positive active material may spread to the negative electrode during long-term recycling of the battery, causing great safety risks.
  • the binder content when the binder content is too high, the binder will hinder the transmission of lithium ions between the positive electrode active materials, making it difficult for lithium ions to be released or embedded, resulting in an increase in the resistance of the electrode film layer and the battery impedance. At the same time, the loading capacity of the positive active material is too low and cannot effectively improve the power performance of the battery.
  • the binder is polyvinylidene fluoride or a modified polymer thereof, and the weight average molecular weight of the binder is 700,000 to 1.1 million.
  • the binder is polyvinylidene fluoride, and its weight average molecular weight is 700,000-1,000,000, 700,000-900,000, 700,000-800,000, 750,000-1.1 million, 800,000-800,000. 1.1 million or 900,000 to 1.1 million.
  • the weight average molecular weight of the binder When the weight average molecular weight of the binder is higher than 1.1 million, the viscosity of the slurry will be too high, the fluidity and filtration performance will be poor, and the stability of the cathode slurry and the processing performance of the pole piece will be reduced; in addition, it will also hinder the lithium
  • the transmission of ions between the positive electrode active materials makes it difficult for lithium ions to be released or embedded, causing the resistance of the electrode film layer and the battery impedance to increase.
  • the weight-average molecular weight of the binder is less than 700,000, the adhesive force of the pole piece is small and demoulding is prone to occur during processing.
  • fluoropolymers with an appropriate mass content range in the cathode slurry can help improve the fluidity, filterability and viscosity of the cathode slurry, and can reduce the DC impedance growth rate of the pole piece. Controlling the weight average molecular weight of the binder can further reduce the cycle internal resistance growth rate of the battery while improving the stability, processability and bonding strength of the positive electrode slurry.
  • the positive active material is a lithium-containing transition metal oxide, which may be lithium iron phosphate or lithium nickel cobalt manganese oxide, or their doping modified materials, or their conductive carbon coatings. At least one of modified materials, conductive metal-coated modified materials, or conductive polymer-coated modified materials.
  • the lithium-containing transition metal oxide may be lithium cobalt oxide, lithium nickel manganese cobalt oxide, lithium nickel manganese aluminate, lithium iron phosphate, lithium vanadium phosphate, lithium cobalt phosphate, lithium manganese phosphate, manganese phosphate Lithium iron, lithium iron silicate, lithium vanadium silicate, lithium cobalt silicate, lithium manganese silicate, spinel type lithium manganate, spinel type lithium nickel manganate, lithium titanate, or their doped modifications or at least one of their conductive carbon-coated modified materials, conductive metal-coated modified materials, or conductive polymer-coated modified materials.
  • the lithium-containing transition metal oxide may be lithium iron phosphate, or their doping modification materials, or their conductive carbon coating modification materials, conductive metal coating modification materials, or conductive polymerization. At least one of the material coating modified materials.
  • the present application provides the use of the above-mentioned fluoropolymer or the fluoropolymer prepared by the above-mentioned method in secondary batteries.
  • the fluoropolymer By using the fluoropolymer, the phenomenon of uneven dispersion of positive electrode active materials such as agglomeration and clogging of filters in the positive electrode slurry can be significantly improved, and the fluidity, filterability and processability of the positive electrode slurry can be improved.
  • Dispersion and/or suspension in the solvent improves the stability of the slurry, reduces the resistance of the electrode film layer and improves battery safety.
  • the application includes the use of the above-mentioned fluoropolymer or the fluoropolymer prepared by the above-mentioned method as a battery slurry dispersant, which can improve the stability of the battery slurry.
  • the above-mentioned fluoropolymer or the fluoropolymer prepared by the above-mentioned method is used as a dispersant for battery cathode slurry.
  • the above-mentioned fluoropolymer or the fluoropolymer prepared by the above-mentioned method is used as a dispersant for battery negative electrode slurry.
  • the application includes the use of the above-mentioned fluoropolymer or the fluoropolymer prepared by the above-mentioned method in improving battery slurry dispersion.
  • the battery slurry is positive electrode slurry or negative electrode slurry.
  • a secondary battery is provided.
  • a secondary battery typically includes a positive electrode plate, a negative electrode plate, an electrolyte and a separator.
  • active ions are inserted and detached back and forth between the positive and negative electrodes.
  • the electrolyte plays a role in conducting ions between the positive and negative electrodes.
  • the isolation film is placed between the positive electrode piece and the negative electrode piece. It mainly prevents the positive and negative electrodes from short-circuiting and allows ions to pass through.
  • the positive electrode sheet includes a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector.
  • the positive electrode film layer includes a positive electrode active material.
  • the positive electrode current collector has two surfaces facing each other in its own thickness direction, and the positive electrode film layer is disposed on any one or both of the two opposite surfaces of the positive electrode current collector.
  • the positive electrode current collector may be a metal foil or a composite current collector.
  • the metal foil aluminum foil can 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 base layer.
  • Composite current collectors can be formed by forming metal materials (aluminum, aluminum alloys, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.) on polymer material substrates (such as polypropylene (PP), polyterephthalate It is formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the cathode active material may be a cathode active material known in the art for batteries.
  • the cathode 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 of batteries can also be used. Only one type of these positive electrode active materials may be used alone, or two or more types may be used in combination.
  • lithium transition metal oxides may include, but are not limited to, lithium cobalt oxides (such as LiCoO 2 ), lithium nickel oxides (such as LiNiO 2 ), lithium manganese oxides (such as LiMnO 2 , LiMn 2 O 4 ), lithium Nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1/3 Co 1/3 Mn 1/3 O 2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O 2 (can also be abbreviated to NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O 2 (can also be abbreviated to NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O 2 (can also be abbreviated to NCM 622 ), LiNi At least one of 0.8 Co 0.1 Mn 0.1 O 2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as Li Li
  • the olivine structure contains Examples of lithium phosphates may include, but are not limited to, lithium iron phosphate (such as LiFePO 4 (also referred to as LFP)), composites of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), lithium manganese phosphate and carbon. At least one of composite materials, lithium iron manganese phosphate, and composite materials of lithium iron manganese phosphate and carbon.
  • lithium iron phosphate such as LiFePO 4 (also referred to as LFP)
  • composites of lithium iron phosphate and carbon such as LiMnPO 4
  • LiMnPO 4 lithium manganese phosphate and carbon.
  • At least one of composite materials, lithium iron manganese phosphate, and composite materials of lithium iron manganese phosphate and carbon At least one of composite materials, lithium iron manganese phosphate, and composite materials of lithium iron manganese phosphate and carbon.
  • the positive electrode film layer optionally further includes a binder.
  • the binder may include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene (HFP) -At least one of tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer and fluorine-containing acrylate resin.
  • PVDF polyvinylidene fluoride
  • PTFE polytetrafluoroethylene
  • HFP vinylidene fluoride-hexafluoropropylene
  • the positive electrode film layer optionally further includes a conductive agent.
  • 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.
  • the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive active material, conductive agent, binder and any other components in a solvent (such as N -methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry is coated on the positive electrode current collector, and after drying, cold pressing and other processes, the positive electrode piece can be obtained.
  • a solvent such as N -methylpyrrolidone
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector, where the negative electrode film layer includes a negative electrode active material.
  • the negative electrode current collector has two opposite surfaces in its own thickness direction, and the negative electrode film layer is disposed on any one or both of the two opposite surfaces of the negative electrode current collector.
  • the negative electrode current collector may be a metal foil or a composite current collector.
  • 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 base material.
  • the composite current collector can be formed by forming metal materials (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as polypropylene (PP), polyterephthalate It is formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the negative active material may be a negative active material known in the art for batteries.
  • the negative 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, and the like.
  • 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 battery negative electrode active materials can also be used. Only one type of these negative electrode active materials may be used alone, or two or more types may be used in combination.
  • the negative electrode film layer optionally further includes a binder.
  • the binder can be selected from styrene-butadiene rubber (SBR), polyacrylic acid (PAA), polysodium acrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), poly At least one of methacrylic acid (PMAA) and carboxymethyl chitosan (CMCS).
  • the negative electrode film layer optionally further includes a conductive agent.
  • the conductive agent 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 optionally includes other auxiliaries, such as thickeners (such as sodium carboxymethylcellulose (CMC-Na)) and the like.
  • thickeners such as sodium carboxymethylcellulose (CMC-Na)
  • the negative electrode sheet can be prepared by dispersing the above-mentioned components for preparing the negative electrode sheet, such as negative active materials, conductive agents, binders and any other components in a solvent (such as deionized water) to form a negative electrode slurry; the negative electrode slurry is coated on the negative electrode current collector, and after drying, cold pressing and other processes, the negative electrode piece can be obtained.
  • a solvent such as deionized water
  • the electrolyte plays a role in conducting ions between the positive and negative electrodes.
  • the type of electrolyte in this application can be selected according to needs.
  • the electrolyte can be liquid, gel, or completely solid.
  • the electrolyte is an electrolyte solution.
  • the electrolyte solution includes electrolyte salts and solvents.
  • the electrolyte salt may be selected from the group consisting of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonimide, lithium bistrifluoromethanesulfonimide, trifluoromethane At least one of lithium sulfonate, lithium difluorophosphate, lithium difluoroborate, lithium dioxaloborate, lithium difluorodioxalate phosphate and lithium tetrafluoroxalate phosphate.
  • the solvent may be selected from the group consisting of ethylene carbonate, propylene carbonate, methylethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, Butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate At least one of ester, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone.
  • the electrolyte optionally further includes additives.
  • additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain properties of the battery, such as additives that improve battery overcharge performance, additives that improve battery high-temperature or low-temperature performance, etc.
  • the secondary battery further includes a separator film.
  • a separator film There is no particular restriction on the type of isolation membrane in this application. Any well-known porous structure isolation membrane with good chemical stability and mechanical stability can be used.
  • the material of the isolation membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.
  • the isolation film can be a single-layer film or a multi-layer composite film, with no special restrictions. When the isolation film is a multi-layer composite film, the materials of each layer can be the same or different, and there is no particular limitation.
  • the positive electrode piece, the negative electrode piece, and the separator film can be made into an electrode assembly through a winding process or a lamination process.
  • the secondary battery may include an outer packaging.
  • the outer packaging can be used to package the above-mentioned electrode assembly and electrolyte.
  • the outer packaging of the secondary battery may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc.
  • the outer packaging of the secondary battery may also be a soft bag, such as a bag-type soft bag.
  • the material of the soft bag may be plastic, and examples of plastic include polypropylene, polybutylene terephthalate, polybutylene succinate, and the like.
  • FIG. 1 shows a square-structured secondary battery 5 as an example.
  • the outer package may include a housing 51 and a cover 53 .
  • the housing 51 may include a bottom plate and side plates connected to the bottom plate, and the bottom plate and the side plates enclose a receiving cavity.
  • the housing 51 has an opening communicating with the accommodation cavity, and the cover plate 53 can cover the opening to close the accommodation cavity.
  • the positive electrode piece, the negative electrode piece and the isolation film can be formed into the electrode assembly 52 through a winding process or a lamination process.
  • the electrode assembly 52 is packaged in the containing cavity.
  • the electrolyte soaks into the electrode assembly 52 .
  • the number of electrode assemblies 52 contained in the secondary battery 5 can be one or more, and those skilled in the art can select according to specific actual needs.
  • secondary batteries can be assembled into battery modules, and the number of secondary batteries contained in the battery module can be one or more. Those skilled in the art can select the specific number according to the application and capacity of the battery module.
  • FIG. 3 is a battery module 4 as an example.
  • a plurality of secondary batteries 5 may be arranged in sequence along the length direction of the battery module 4 .
  • the plurality of secondary batteries 5 can be fixed by fasteners.
  • the battery module 4 may further include a housing having a receiving space in which a plurality of secondary batteries 5 are received.
  • the above-mentioned battery modules can also be assembled into a battery pack.
  • the number of battery modules contained in the battery pack can be one or more. Those skilled in the art can select the specific number according to the application and capacity of the battery pack.
  • the battery pack 1 may include a battery box and a plurality of battery modules 4 disposed in the battery box.
  • the battery box includes an upper box 2 and a lower box 3 .
  • the upper box 2 can be covered with the lower box 3 and form a closed space for accommodating the battery module 4 .
  • Multiple battery modules 4 can be arranged in the battery box in any manner.
  • the present application also provides an electrical device, which includes at least one of the secondary battery, battery module, or battery pack provided by the present application.
  • the secondary battery, battery module, or battery pack may be used as a power source for the electrical device, or may be used as an energy storage unit for the electrical 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, and electric golf carts). , electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but are not limited to these.
  • a secondary battery, a battery module or a battery pack can be selected according to its usage requirements.
  • Figure 6 is an electrical device as an example.
  • the electric device is a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, etc.
  • a battery pack or battery module can be used.
  • the device may be a mobile phone, a tablet, a laptop, etc.
  • the device is usually required to be thin and light, and a secondary battery can be used as a power source.
  • N-methylpyrrolidone was added to the cathode active material lithium iron phosphate (LFP), conductive agent carbon black, binder and dispersant prepared in Example 1 in a weight ratio of 92:4:3.95:0.05 and stirred evenly.
  • a cathode slurry with a solid content of 58% was obtained.
  • the positive electrode slurry is evenly coated on both surfaces of the aluminum foil positive electrode current collector, and then dried to obtain a film layer; it is then cold pressed and cut to obtain the positive electrode sheet.
  • the binder is PVDF with a weight average molecular weight of 700,000 purchased from Arkema France Co., Ltd.
  • SBR binder styrene-butadiene rubber
  • CMC thickener sodium carboxymethylcellulose
  • the positive electrode sheet, isolation film and negative electrode sheet prepared in Example 1 are stacked in order so that the isolation film is between the positive and negative electrode sheets to play an isolation role. Then, the bare battery core is obtained by winding and welding to the bare battery core. The tabs are removed, and the bare battery core is put into an aluminum case, baked at 80°C to remove water, and then electrolyte is injected and sealed to obtain an uncharged battery. The uncharged battery then undergoes processes such as standing, hot and cold pressing, formation, shaping, and capacity testing to obtain the lithium-ion battery product of Example 1.
  • the batteries of Examples 2 to 24 and the batteries of Comparative Examples 1 to 7 have the same preparation steps as the battery of Example 1, but the amounts of binder, dispersant and cathode material are adjusted.
  • the different parameters are detailed in Table 1 and Table 2 .
  • Example 2 the battery preparation method is the same as in Example 1. The difference is that the mass content of the binder and the dispersant in the positive electrode sheet is controlled to 4%, and the mass ratio of the two is adjusted.
  • the specific parameters are as shown in Table 1 and shown in Table 2.
  • Example 8 the battery preparation method is the same as that in Example 3, except that the dispersant uses a PVDF polymer with a weight average molecular weight of 0.5 million.
  • the preparation method of PVDF polymer with a weight average molecular weight of 0.5 million is:
  • Example 9 the battery preparation method is the same as that in Example 3, except that the dispersant uses a PVDF polymer with a weight average molecular weight of 20,000.
  • the preparation method of PVDF polymer with a weight average molecular weight of 20,000 is:
  • Example 10 the battery preparation method is consistent with Example 3. The difference is that: the weight average molecular weight of the binder is 900,000; the positive active material is lithium nickel cobalt manganese oxide NCM, and the remaining parameters are as shown in Table 1 and As shown in Table 2.
  • the weight average molecular weight of the binder was adjusted to 900,000. Other parameters are shown in Table 1 and Table 2.
  • the battery preparation method was basically the same as in Example 3, except that the relevant mass ratio was adjusted.
  • Example 14 the battery preparation method is consistent with Example 3, except that: the weight average molecular weight of the binder is 1.1 million; the positive active material is lithium nickel cobalt manganese oxide NCM: conductive agent: binder: dispersed The mass ratio of the agent is 95:3:1.95:0.05.
  • the binder PVD with a weight average molecular weight of 1.1 million was purchased from Solvay (Shanghai) Co., Ltd.
  • Example 15-17 the battery preparation method is the same as that in Example 14. The difference is that the mass content of the binder and the dispersant in the positive electrode sheet is controlled to 2%, and the mass ratio of the two is adjusted.
  • the specific parameters are as shown in Table 1 and shown in Table 2.
  • Example 18 the battery preparation method is the same as that in Example 15. The difference is that the preparation method of the dispersant is the same as the preparation method of the dispersant in Example 8, and the weight average molecular weight is 0.5 million.
  • Example 19 the battery preparation method is the same as that in Example 15. The difference is that the preparation method of the dispersant is the same as the preparation method of the dispersant in Example 9, and the weight average molecular weight is 20,000.
  • Example 20 the dispersant uses a PTFE polymer with a weight average molecular weight of 10,000, and its preparation method is:
  • Example 21 the dispersant uses polychlorotrifluoroethylene with a weight average molecular weight of 10,000, and its preparation method is:
  • Example 22 the dispersant uses PVDF-HFP (vinylidene fluoride-hexafluoropropylene) polymer with a weight average molecular weight of 10,000, and its preparation method is:
  • Example 23 The preparation methods of the dispersants in Examples 23 and 24 are basically similar to those in Example 22, except that the comonomers are substituted with tetrafluoroethylene and chlorotrifluoroethylene respectively.
  • Comparative Example 1 only a PVDF binder with a weight average molecular weight of 700,000 was used to prepare the battery, and other steps were the same as Example 1.
  • Comparative Example 2 only a PVDF binder with a weight average molecular weight of 1.1 million was used to prepare the battery, and other steps were the same as in Example 10.
  • the preparation method in Comparative Example 3 is basically the same as that in Example 3. The difference is that the dispersant uses a PVDF polymer with a weight average molecular weight of 30,000, and the preparation method is:
  • Comparative Example 4 a PVDF polymer with a weight average molecular weight of 30,000 was used as the dispersant, and the remaining steps were the same as in Example 11.
  • the GB/T 19077-2016 particle size distribution laser diffraction method weigh 0.1g to 0.13g of the polymer sample to be tested in a 50mL beaker, add 5g of absolute ethanol, put in a stirrer of about 2.5mm, and seal it with plastic wrap. After ultrasonic treatment for 5 minutes, the samples were transferred to a magnetic stirrer and stirred at 500 rpm for more than 20 minutes. Two samples were taken from each batch of products for testing. The test was carried out using the Mastersizer 2000E laser particle size analyzer of Malvern Instruments Co., Ltd. in the UK.
  • NMP N-methylpyrrolidone
  • Solid content test method Prepare a glass petri dish and record the weight m 1 , take a part of the prepared cathode slurry and put it into the glass petri dish and record the total weight m 2 , put the petri dish containing the cathode slurry into the drying box Medium heating, heating temperature 120°C, heating time 1h. Weigh and record the weight m 3 of the dried petri dish, and calculate it according to the following formula:
  • the viscosity of the slurry was measured using a rotational viscometer. Select the appropriate rotor, fix the viscometer rotor, and place the positive slurry under the viscometer rotor so that the slurry just submerges the scale line of the rotor.
  • the battery DC impedance measurement method is as follows:
  • Example 1 the battery DC impedance DCR test process is as follows: at 25°C, charge the battery corresponding to Example 1 with a constant current of 1/3C to 3.65V, and then charge with a constant voltage of 3.65V until the current is 0.05 C. After leaving it for 5 minutes, record the voltage V1. Then discharge at 1/3C for 30 seconds and record the voltage V2, then (V2-V1)/1/3C, we get the internal resistance DCR1 of the battery after the first cycle.
  • the DC impedance increase ratio of the battery in Example 1 in Table 2 is calculated according to the following formula:
  • Comparative Example 1 The testing procedures of Comparative Example 1 and other examples are the same as above.
  • the data in Table 2 are measured after 500 cycles under the above test conditions.
  • the measurement method is as follows:
  • the battery DC impedance DCR test process is as follows: at 25°C, charge the battery corresponding to Example 10 with a constant current of 1/3C to 4.4V, and then charge with a constant voltage of 4.4V until the current is 0.05 C. After leaving it for 5 minutes, record the voltage V1. Then discharge at 1/3C for 30 seconds and record the voltage V2, then (V2-V1)/1/3C, we get the internal resistance DCR1 of the battery after the first cycle. Other steps are the same as the battery DC impedance DCR test method of lithium iron phosphate cathode active material.
  • the indicator light is on, adjust the limit block to the appropriate position, and fix the end of the steel plate that is not attached to the pole piece sample with the lower clamp. Fold the paper tape upward and fix it with the upper clamp. Use the "up” and “down” buttons on the manual controller attached to the tensile machine to adjust the position of the upper clamp, then test and read the value. Divide the force of the pole piece when the force is balanced by the width of the tape as the bonding force of the pole piece per unit length to characterize the bonding strength between the positive electrode film layer and the current collector.
  • Comparative Example 1 only a PVDF binder with a weight average molecular weight of 700,000 was used to prepare the cathode slurry.
  • the fluidity, slurry viscosity and filterability of the slurry were poor, resulting in uneven dispersion of the cathode slurry and poor processability. , it is difficult to produce high-quality cathode plates.
  • Comparative Example 2 only a PVDF binder with a weight average molecular weight of 1.1 million was used to prepare the cathode slurry.
  • the cathode active materials in the cathode slurry are prone to agglomeration, causing the cathode slurry to be unevenly dispersed, resulting in the fluidity and slurry dispersion of the cathode slurry.
  • the material viscosity and filterability are poor, which in turn increases the DC impedance growth rate.
  • Examples 1 to 24 a fluoropolymer with a weight average molecular weight of 0.5 million to 20,000 and a PVDF binder with a weight average molecular weight of 700,000 to 1.1 million were used to prepare positive electrode slurry, in which the mass content of the dispersant was 0.05% to 0.7%, the mass content of the binder is 1.4% to 4%, and the viscosity of the prepared cathode slurry is 2000 to 50000 mPa ⁇ s.
  • Comparative Examples 5 and 6 respectively used different types of dispersants and PVDF binders to prepare positive electrode slurries.
  • the filtration speed of the positive electrode slurry was slow and there was filter residue.
  • the dispersion of the slurry was poor, resulting in an increase in the DC impedance growth rate of the positive electrode plates. .
  • Example 1 and Example 10 are significantly improved in filtration performance, the processability of the positive electrode slurry is improved and the DC resistance growth rate of the pole piece is reduced, and in terms of bonding performance, Pole pieces have better adhesion.
  • Examples 1 to 9 use a dispersant with a weight average molecular weight of 0.5 to 20,000, a median particle diameter Dv50 of 0.5 to 1 ⁇ m, and a viscosity of 20 to 50 mPa ⁇ s, and a PVDF binder with a weight average molecular weight of 700,000.
  • a dispersant with a weight average molecular weight of 0.5 to 20,000, a median particle diameter Dv50 of 0.5 to 1 ⁇ m, and a viscosity of 20 to 50 mPa ⁇ s, and a PVDF binder with a weight average molecular weight of 700,000.
  • Comparative Example 3 which uses a dispersant with a weight average molecular weight of 30,000, a median particle diameter Dv50 of 1.3 ⁇ m, and a viscosity of 60 mPa ⁇ s, and a PVDF binder with a weight average molecular weight of 700,000 to prepare the cathode slurry.
  • the fluidity, viscosity and filtration performance of the cathode slurry are significantly improved. Due to the improved dispersion of the cathode slurry, the stability and processability of the cathode slurry are improved.
  • Examples 14 to 19 were prepared using a dispersant with a weight average molecular weight of 0.5 to 20,000, a median particle diameter Dv50 of 0.5 to 1 ⁇ m, a viscosity of 20 to 50 mPa ⁇ s, and a PVDF binder with a weight average molecular weight of 110.
  • Cathode slurry Compared with Comparative Example 4, which uses a dispersant with a weight average molecular weight of 30,000, a median particle diameter Dv50 of 1.3 ⁇ m, and a viscosity of 20 to 60 mPa ⁇ s, and a PVDF binder with a weight average molecular weight of 1.1 million to prepare a cathode slurry. , which has significantly improved the fluidity, viscosity and filtration performance of the cathode slurry, and improved the DC impedance growth rate of the pole piece.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Inorganic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

本申请提供了一种分散剂、粘结剂组合物、正极浆料、二次电池、电池模块、电池包及用电装置。其中，分散剂为含有式I所示结构单元的含氟聚合物，且所述含氟聚合物的重均分子量小于等于2万，在式I所述结构单元中，R 1、R 2各自独立地选自氢、氟、氯或三氟甲基。所述含氟聚合物可以改善正极浆料的流动性和过滤性，提高浆料的稳定性和加工性，同时该含氟聚合物的添加不会如传统分散剂一样导致极片粘结性能的大幅度下降，有利于降低电池循环过程中直流阻抗的增长率。

Description

分散剂、粘结剂组合物、正极浆料、二次电池、电池模块、电池包及用电装置
交叉引用
本申请引用于2022年8月30日递交的名称为“含氟聚合物、其制备方法和用途、正极浆料、二次电池、电池模块、电池包及用电装置”的第202211044631.4号中国专利申请，其通过引用被全部并入本申请。
技术领域
本申请涉及二次电池技术领域，尤其涉及一种含氟聚合物、其制备方法和用途、二次电池、电池模块、电池包和用电装置。
背景技术
近年来，随着二次电池的应用范围越来越广泛，二次电池广泛应用于水力、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。
开发新型正极活性材料进一步提高二次电池的功率性能以满足用电装置续航能力的要求是目前的研究热点。然而，传统粘结剂与新型正极活性材料相容性差，导致正极浆料容易发生颗粒团聚、分层、沉淀等问题，使得极片品质难以保证。因此，如何提高正极浆料的分散性和稳定性以提高极片质量和电池性能是目前亟需解决的问题。
发明内容
本申请是鉴于上述课题而进行的，其目的在于，提供一种可以加强浆料分散性、提高浆料稳定性的分散剂。
为了达到上述目的，本申请的第一方面提供了分散剂，所述分 散剂为含有式I所示结构单元的含氟聚合物，且所述含氟聚合物的重均分子量小于等于2万，可选为0.5万～2万，
Figure PCTCN2023071658-appb-000001
其中，R 1、R 2各自独立地选自氢、氟、氯或三氟甲基。
本申请提供的分散剂中使用了重均分子量小于等于2万、含有式I结构单元的含氟聚合物，改善正极浆料的流动性和过滤性，提高浆料的稳定性和加工性，同时该含氟聚合物的添加不会如传统分散剂一样导致极片粘结性能的大幅度下降，有利于降低电池循环过程中直流阻抗的增长率。
在任意实施方式中，R 1选自氢、氟或三氟甲基，且R 2选自氢、氟、氯或三氟甲基，或者R 1选自氢、氟、氯或三氟甲基，且R 2选自氢、氟或三氟甲基。在任意实施方式中，含氟聚合物的重均分子量为0.5万～2万。
在任意实施方式中，所述含有式I所示结构单元的聚合物为氟代烃聚合物，选自聚四氟乙烯、聚偏二氟乙烯、偏二氟乙烯和六氟丙烯的共聚物中的一种或多种。
含有式I所示结构单元的聚合物中，重均分子量小于等于2万的上述聚合物与正极活性材料具有较好的粘附，显著改善浆料的分散性能，使得正极活性材料在极片表面均匀分布。
在任意实施方式中，所述含氟聚合物颗粒的中值粒径Dv50为0.5～1μm。此粒径范围内的聚合物颗粒有利于聚合物在正极浆料溶剂，例如N-甲基吡咯烷酮中的溶解，降低胶液的加工难度。
在任意实施方式中，所述含氟聚合物溶于N-甲基吡咯烷酮制得胶液，当所述胶液中所述聚合物的质量百分含量为7％时，胶液的粘度为20～50mPa·s。此粘度范围内的聚合物有助于含氟聚合物与正极活性材料的充分粘附，减少正极活性材料团聚、堵塞滤网等现象，改善浆料的分散性能和有助于提高浆料的固含量。
本申请的第二方面还提供一种粘结剂组合物，包含粘结剂和本申请任意实施方式中的分散剂。
在任意实施方式中，粘结剂为重均分子量为70万～110万的聚偏二氟乙烯或其改性聚合物。
控制粘结剂的重均分子量能够在提高正极浆料的稳定性、加工性以及正极极片粘结力的同时进一步降低电池的循环内阻增长率。
在任意实施方式中，分散剂和所述粘结剂的质量比为1:80～1:2。
在任意实施方式中，所述分散剂和所述粘结剂的质量比为1:40～1:4。本申请的第二方面还提供一种含氟聚合物的制备方法，该方法包括：提供至少一种式II所示单体，
Figure PCTCN2023071658-appb-000002
其中，R 1、R 2各自独立地选自氢、氟、氯、三氟甲基中的一种或多种；
在可聚合条件下聚合所述单体制备聚合物，所述聚合物的重均分子量小于等于2万，可选为0.5万～2万。
本申请提供的制备方法中，制备的含氟聚合物具有较低的重均分子量和粘度，与正极活性材料具有良好的粘附作用，并通过聚合物的空间位阻避免正极活性材料，例如磷酸铁锂(LFP)粉体颗粒间的团聚，使得浆料稳定性增加。
在任意实施方式中，所述制备方法还包括以下步骤：
将至少一种式II所示单体在非反应性气体氛围、常压、60℃～80℃的反应温度下进行聚合反应2小时～5小时，停止反应，固液分离，保留固相。
在任意实施方式中，还包括以下步骤：
向容器中加入反应溶剂和分散助剂，对所述容器充入非反应性气体；
向所述容器中加入引发剂和pH调节剂，调节pH值至6.5～7，然后加入式II所示单体，搅拌0.5小时～1小时后，升温至60℃～80℃，进行聚合反应。
上述制备方法中，通过在选定的条件下，可以获得本申请第一方面提供的含有式I所示结构单元的聚合物。该制备方法原材料成本低，反应条件相对温和，有利于含氟聚合物的量产。
本申请的第三方面提供一种正极浆料，所述正极浆料中包括任意实施方式中的粘结剂组合物。
所述正极浆料通过使用本申请第一方面所述的分散剂，提高了对正极活性材料的粘附力和减少了正极活性材料粉体的团聚，显著改善了正极浆料的分散性、稳定性和加工性，有利于制备高压密、高面密度的正极极片。
在任意实施方式中，所述正极浆料在N-甲基吡咯烷酮中的固含量为58％时，所述正极浆料的粘度为2000～50000mPa·s，可选为2500～47000mPa·s。所述粘度范围内的正极浆料的流动性和过滤性显著改善，提高了正极浆料的稳定性和加工性。
在任意实施方式中，所述分散剂的质量含量为0.05％～0.7％，可选为0.1％～0.6％，基于所述正极浆料中固体物质的总质量计。在正极浆料中使用此质量含量的含氟聚合物，有助于改善正极浆料的流动性、过滤性和粘度，并能够降低极片的直流阻抗增长率。
在任意实施方式中，所述正极浆料中所述粘结剂的质量含量为1.4％～4％，可选为1.6％～3.9％，基于所述正极浆料中固体物质的总质量计。粘结剂的质量含量在此范围内，有助于正极浆料中固体物质间的粘附和粘接，正极活性材料和导电剂稳定连接，保证极片的完整性；并有效地避免正极活性材料与电解液的直接接触，减少副反应的发生，以及抑制直流阻抗的增加。
在任意实施方式中，正极浆料中包含正极活性材料，所述正极活性材料为含锂的过渡金属氧化物，可选为磷酸铁锂或锂镍钴锰氧 化物，或它们的掺杂改性材料、或它们的导电碳包覆改性材料、导电金属包覆改性材料或导电聚合物包覆改性材料中的至少一种。
本申请的第四方面提供了第一方面所述的分散剂或第三方面所述方法制备的分散剂在二次电池中的应用。通过使用所述含氟聚合物，可以显著改善正极浆料中正极活性材料团聚、堵塞滤网等分散不均匀的现象，提高正极浆料的流动性、过滤性和加工性，通过在正极浆料溶剂中分散和/或悬浮提高浆料的稳定性。
本申请的第五方面提供一种二次电池，包括本申请第一方面提供的含氟聚合物或根据本申请第二方面的方法制备的正极活性材料或根据本申请第三方面提供的正极活性材料，正极极片、隔离膜、负极极片以及电解液。在任选的实施方式中，所述二次电池为锂离子电池或钠离子电池。
本申请的第六方面提供一种电池模块，包括本申请的第五方面的二次电池。
本申请的第七方面提供一种电池包，包括本申请的第六方面的电池模块。
本申请的第八方面提供一种用电装置，包括选自本申请的第五方面的二次电池、本申请的第六方面的电池模块或本申请的第七方面的电池包中的至少一种。
附图说明
图1是本申请一实施方式的二次电池的示意图；
图2是图1所示的本申请一实施方式的二次电池的分解图；
图3是本申请一实施方式的电池模块的示意图；
图4是本申请一实施方式的电池包的示意图；
图5是图4所示的本申请一实施方式的电池包的分解图；
图6是本申请一实施方式的二次电池用作电源的用电装置的示意图。
附图标记说明：
1电池包；2上箱体；3下箱体；4电池模块；5二次电池；51壳 体；52电极组件；53盖板。
具体实施方式
以下，适当地参照附图详细说明具体公开了本申请的正极活性材料及其制造方法、正极极片、二次电池、电池模块、电池包和电学装置的实施方式。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。
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。
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，也可以是封闭式。例如，所述“包括”和“包含”可以表示还可以包括或包含没有列出的其他组分，也可以仅包括或包含列出的组分。
如果没有特别的说明，在本申请中，术语“或”是包括性的。举例来说，短语“A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)。
新一代正极活性材料因其低成本、高性能和安全性得到了业界的广泛关注。然而，他们往往具有比表面积大、颗粒度小、碳包覆后表面碳元素包覆量大、石墨化程度高并具有微孔结构等等特点，导致新一代正极活性材料在浆料中的稳定性差，在制浆过程中易产生团聚、堵塞滤网等现象，浆料分散性差、易沉淀、粘度大、固含量低，进而其制备的极片表面容易出现开裂、脱膜、颗粒划痕、针孔等缺陷，且极片中的正极活性材料分布不均匀、极片质量不均一。
[分散剂]
基于此，本申请提供了一种分散剂，所述分散剂为含有式I所示结构单元的含氟聚合物，
Figure PCTCN2023071658-appb-000003
其中，R 1、R 2各自独立地选自氢(H)、氟(F)、氯(Cl)或三氟甲基(-CF 3)。
本申请中，术语“分散剂”是指促使物料颗粒均匀分散于胶体 溶液或胶体分散液的化学化合物、聚合物或混合物。
在本文中，术语“聚合物”一方面包括通过聚合反应制备的化学上均一的、但在聚合度、摩尔质量和链长方面不同的大分子的集合体。该术语另一方面也包括由聚合反应形成的这样的大分子集合体的衍生物，即可以通过上述大分子中的官能团的反应，例如加成或取代获得的并且可以是化学上均一的或化学上不均一的化合物或混合物。
在一些实施方式中，所述含氟聚合物用于电池浆料，作为一种具有分散作用的聚合物提高浆料的分散性。在一些实施方式中，所述含氟聚合物用于电池正极浆料，提高正极浆料的分散性。在一些实施方式中，所述含氟聚合物用于电池负极浆料，提高负极浆料的分散性。
在本文中，术语“正极”也指电池中的“阴极”。术语“负极”也指电池中的“阳极”。
在一些实施方式中，R 1选自氢、氟或三氟甲基，且R 2选自氢、氟、氯或三氟甲基，或者R 1选自氢、氟、氯或三氟甲基，且R 2选自氢、氟或三氟甲基。
在一些实施方式中，所述含氟聚合物为氟代烃聚合物，选自聚四氟乙烯、聚偏二氟乙烯、偏二氟乙烯和六氟丙烯的共聚物中的一种或多种。
在本文中，术语“氟代烃聚合物”是指由氟基取代的不饱和烃单体聚合形成的聚合物。
在一些实施方式中，含氟聚合物的重均分子量小于等于2万，可选为0.5万～2万。
在本文中，术语“重均分子量”是指聚合物中用不同分子量的分子所占的重量分数与其对应的分子量乘积的总和。
不受任何理论的约束，含有式I所示结构单元的聚合物中，重均分子量小于等于2万时，分子间作用力比较小，粘附力和浸润性能良好，可以很好地粘附正极浆料中的正极活性材料，防止/减少正极 活性材料之间聚集；同时，重均分子量不超过2万的聚合物在正极浆料的溶剂(或分散介质)中，通过静电排斥或空间位阻作用，分散或悬浮于溶剂中，进而使得正极浆料分散性显著提高，在一定时间内放置不沉降，改善了正极浆料的流动性和过滤性，提高浆料的固含量和极片涂布速率，正极活性材料在极片中的均匀分布有利于降低电池在循环过程中直流阻抗的增长率。同时该含氟聚合物中具有极性较强的氟官能团，该含氟聚合物的添加不会如传统分散剂一样，导致极片粘结性能的大幅度下降，有利于电池综合性能的提高。
在一些实施方式中，含有式I所示结构单元的聚合物能够溶解于油性溶剂。在一些实施例中，含有式I所示结构单元的聚合物能够溶解于水性溶剂中。示例性的油性溶剂包括二甲基乙酰胺、N，N-二甲基甲酰胺、N-甲基吡咯烷酮、丙酮和碳酸二甲酯。水性溶剂的示例包括但不限于水。
在一些实施方式中，含氟聚合物的颗粒的中值粒径Dv50为0.5～1μm。在一些实施方式中，含氟聚合物的颗粒的中值粒径Dv50为0.5～0.8μm，或者为0.8～1μm，或者为0.6～0.9μm。此粒径范围内的聚合物颗粒有利于聚合物在正极浆料溶剂，例如N-甲基吡咯烷酮中的溶解，降低胶液的加工难度，提高极片的加工效率。
在本文中，术语“中值粒径Dv50”是指测量样品的累计粒度分布百分数达到50％时所对应的粒径。
在一些具体的实施方式中，所述聚合物溶于N-甲基吡咯烷酮制得的胶液的粘度为20～50mPa·s，且所述胶液中所述聚合物的质量百分含量为7％。在一些实施方式中，所述聚合物溶于N-甲基吡咯烷酮制得的胶液的粘度为20～45mPa·s，或者为20～40mPa·s，或者为20～35mPa·s，或者为25～50mPa·s，或者为30～50mPa·s，或者为35～50mPa·s，或者为40～50mPa·s。
由于此粘度范围内的聚合物有助于含氟聚合物与正极活性材料的充分粘附，减少正极活性材料团聚、堵塞滤网等现象，改善浆料的分散性能和有助于提高浆料的固含量。与正极活性材料具有较好 的粘附，显著改善浆料的分散性能，使得正极活性材料在极片表面均匀分布。
本申请还提供一种上述分散剂的制备方法，所述分散剂为含氟聚合物，该方法包括：提供至少一种式II所示单体，
Figure PCTCN2023071658-appb-000004
其中，R 1、R 2各自独立地选自氢、氟、氯、三氟甲基中的一种或多种；
在可聚合条件下聚合所述单体制备含氟聚合物，所述含氟聚合物的重均分子量小于等于2万。
在一些实施方式中，所述含氟聚合物的重均分子量为0.5万～2万。
在本文中，术语“可聚合条件”是指包括本领域技术人员选择的温度、压力、反应物浓度、任选的溶剂/稀释剂、反应物混合/添加参数的那些条件，有助于一种或多种单体在至少一个聚合反应器内反应的其他条件。
在一些实施方式中，所述制备方法还包括以下步骤：
将至少一种式II所示单体在非反应性气体氛围、常压、60℃～80℃的反应温度下进行聚合反应2小时～5小时，停止反应，固液分离，保留固相。
术语“非反应性气体”是指不会参与聚合反应的气体，示例性的非反应性气体包括氩气、氦气和氮气中的任意或组合。
术语“常压”指一个标准大气压，即101KPa。
在一些实施方式中，反应温度为65℃～80℃，70℃～80℃或者66℃～80℃，68℃～80℃，73℃～80℃，65℃～75℃或者66℃～73℃。
在一些实施方式中，反应时间为2小时～4小时、1小时～3小时或2小时～3小时。
在一些实施方式中，还包括以下步骤：
向容器中加入反应溶剂和分散助剂，对所述容器充入非反应性 气体；
向所述容器中加入引发剂和pH调节剂，调节pH值至6.5～7，然后加入式II所示单体，搅拌0.5小时～1小时后，升温至60℃～80℃，进行聚合反应。
术语“引发剂”是指在聚合反应中，能引发单体进行聚合反应的物质。示例性引发剂如2-乙基过氧化二碳酸酯，过氧化叔戊基新戊酸酯。
术语“pH调节剂”是指可以改变溶液或分散介质酸碱度的物质，包括提高酸度或提高碱度。示例性的pH调节剂如碳酸氢钠，碳酸钠和氢氧化钠。
术语“分散助剂”是指在合成反应中能够促进单体均匀分散于介质中的物质。示例性的分散助剂包括羧乙基纤维素醚。
在一些实施方式中，所述反应溶剂为水，有利于降低对环境的危害。
在一些实施方式中，调节pH值至6.5，6.8或7。
在一些实施方式中，搅拌时间为30分钟～55分钟，30分钟～50分钟，30分钟～45分钟，35分钟～60分钟，40分钟～60分钟或者45分钟～60分钟。
上述制备方法中，通过在选定的条件下，可以获得重均分子量小于等于2万的含有式I所示结构单元的聚合物。本申请提供的制备方法中，制备的含氟聚合物具有合适的重均分子量和粘度，与正极活性材料具有良好的粘附作用，显著提高浆料的分散性和稳定性。
所述制备方法原料来源广泛、成本低，反应条件温和，对环境危害较小，有利于含氟聚合物的量产。
[正极浆料]
本申请提出了一种正极浆料，所述正极浆料中包括正极活性材料，导电剂，粘结剂以及本申请上述的分散剂。
所述正极浆料通过使用上述分散剂，提高了对正极活性材料的粘附力和减少了正极活性材料粉体的团聚，显著改善了正极浆料的 分散性、稳定性和加工性，有利于制备高压密、高面密度的正极极片。
在一些实施方式中，使用N-甲基吡咯烷酮制备正极浆料。
在一些实施方式中，所述正极浆料在N-甲基吡咯烷酮中的固含量为58％时，所述正极浆料的粘度为2000～50000mPa·s。
在一些实施方式中，所述正极浆料在N-甲基吡咯烷酮中的固含量为58％时，所述正极浆料的粘度为2500～47000mPa·s，2700～44000mPa·s，2500～33000mPa·s，2500～32000mPa·s或者2500～33000mPa·s。
当正极浆料在N-甲基吡咯烷酮中的固含量为58％且正极浆料的粘度高于50000mPa·s时，极片的粘结力虽然可能会提高，但浆料的流动性和过滤性能会降低，使得浆料中正极活性材料分布不均匀，不仅影响极片加工性能，制备的极片表面容易出现开裂、颗粒划痕、针孔等缺陷，影响极片的质量。当正极浆料在N-甲基吡咯烷酮中的固含量为58％且正极浆料的粘度低于2000mPa·s时，极片的流动性和过滤性能虽然显著提高，但是极片的粘结力严重降低，极片表面极易出现脱膜缺陷，严重危害使用该极片的电池的安全性。
在上述设定粘度范围内的正极浆料的流动性和过滤性显著改善，使正极活性材料分布均匀，提高了正极浆料的稳定性和加工性；进而有利于降低极片的电子电阻，降低直流阻抗增长率，提高了极片的质量。
在一些实施方式中，所述分散剂和所述粘结剂的质量比为1:80～1:2。
在一些实施方式中，所述分散剂和所述粘结剂的质量比为1:40～1:4，1:20～1:4，1:10～1:4，1:40～1:10或者1:40～1:20。
当所述含氟聚合物和所述粘结剂的质量比低于1:80时，由于含氟聚合物的含量过低，无法充分包覆正极浆料中的正极活性材料，不利于正极活性材料的分散，容易产生正极浆料粉体团聚、堵塞滤网等现象，影响正极浆料的稳定性和极片的加工性，导致膜层电阻 增高。当所述含氟聚合物和所述粘结剂的质量比高于1:2时，由于含氟聚合物的含量过高，含氟聚合物无法将足量的导电剂和正极活性材料粘结到一起，极片的粘结力小，容易在加工过程中出现脱模现象或者电池在长期循环使用过程中正极活性材料扩散到负极，造成极大的安全隐患。
所述分散剂和所述粘结剂的质量比在合适范围内可以确保正极活性材料与含氟聚合物的充分包覆，通过良好的粘附力促进正极活性材料在粘结剂中分散均匀，提高正极浆料的稳定性和加工性。
在一些实施方式中，所述分散剂的质量含量为0.05％～0.7％，基于所述正极浆料中固体物质的总质量计。
在一些实施方式中，所述分散剂的质量含量为0.05％～0.6％，0.05％～0.5％，0.05％～0.4％，0.05％～0.3％，0.1％～0.7％，0.2％～0.7％，0.3％～0.7％，0.2％～0.6％或者0.3％～0.6％，基于所述正极浆料中固体物质的总质量计。
当分散剂的质量含量低于0.05％时，同样地，不利于正极活性材料的分散，容易产生正极浆料粉体团聚、堵塞滤网等现象，影响正极浆料的稳定性和极片的加工性，导致膜层电阻增高。当所述含氟聚合物的含量高于0.7％时，同样地，导致极片的粘结力小，容易在加工过程中出现脱模现象或者电池在长期循环使用过程中正极活性材料扩散到负极，造成极大的安全隐患。在正极浆料中使用此质量含量范围的含氟聚合物，有助于改善正极浆料的流动性、过滤性和粘度，并能够降低极片的直流阻抗增长率。
在一些实施方式中，所述正极浆料中所述粘结剂的质量含量为1.4％～4％，基于所述正极浆料中固体物质的总质量计。
在一些实施方式中，所述正极浆料中所述粘结剂的质量含量为3.3％～3.9％，3.4％～3.9％，3.5％～3.9％，3.6％～3.9％，3.7％～3.9％，1.6％～1.95％，1.6％～1.8％，1.6％～1.7％，1.6％～3.9％，1.6％～3.8％，1.6％～3.7％，1.6％～3.6％，1.6％～3.5％，1.6％～3.4％或者1.6％～3.3％，基于所述正极浆料中固体物质的总质量计。
粘结剂含量过低时，粘结剂无法将足量的导电剂和正极活性材料粘结到一起，极片的粘结力小，容易在加工过程中出现脱模现象；含量过低还会导致粘结剂无法在正极活性材料的表面形成紧密粘附，电池在长期循环使用过程中正极活性材料可能会扩散到负极，造成极大的安全隐患。相反，粘结剂含量过高时，粘结剂会阻碍锂离子在正极活性材料间的传输，使得锂离子不易放出或嵌入，导致极片膜层的电阻和电池阻抗增加。同时正极活性材料的负载量过低，无法有效提高电池的功率性能。
在一些实施方式中，所述粘结剂为聚偏二氟乙烯或其改性聚合物，所述粘结剂的重均分子量为70万～110万。
在一些实施方式中，所述粘结剂为聚偏二氟乙烯，其重均分子量为70万～100万，70万～90万，70万～80万，75万～110万，80万～110万或者90万～110万。
当粘结剂的重均分子量高于110万时，会导致浆料的粘度过高，流动性和过滤性能变差，正极浆料的稳定性和极片加工性能降低；另外，还会阻碍锂离子在正极活性材料间的传输，使得锂离子不易放出或嵌入，导致极片膜层的电阻和电池阻抗增加极片膜层的电阻增加。当粘结剂的重均分子量低于70万时，极片的粘结力小，容易在加工过程中出现脱模现象。在正极浆料中使用合适质量含量范围的含氟聚合物，有助于改善正极浆料的流动性、过滤性和粘度，并能够降低极片的直流阻抗增长率。控制粘结剂的重均分子量能够在提高正极浆料的稳定性、加工性以及正极极片粘结力的同时进一步降低电池的循环内阻增长率。
在一些实施方式中，所述正极活性材料为含锂的过渡金属氧化物，可选为磷酸铁锂或锂镍钴锰氧化物，或它们的掺杂改性材料、或它们的导电碳包覆改性材料、导电金属包覆改性材料或导电聚合物包覆改性材料中的至少一种。
在一些实施方式中，含锂的过渡金属氧化物可选为钴酸锂、镍锰钴酸锂、镍锰铝酸锂、磷酸铁锂、磷酸钒锂、磷酸钴锂、磷酸锰 锂、磷酸锰铁锂、硅酸铁锂、硅酸钒锂、硅酸钴锂、硅酸锰锂、尖晶石型锰酸锂、尖晶石型镍锰酸锂、钛酸锂，或它们的掺杂改性材料、或它们的导电碳包覆改性材料、导电金属包覆改性材料或导电聚合物包覆改性材料中的至少一种。在一些实施方式中，含锂的过渡金属氧化物可选为磷酸铁锂、或它们的掺杂改性材料、或它们的导电碳包覆改性材料、导电金属包覆改性材料或导电聚合物包覆改性材料中的至少一种。
在一些实施方式中，本申请提供了上述含氟聚合物或上述方法制备的含氟聚合物在二次电池中的应用。通过使用所述含氟聚合物，可以显著改善正极浆料中正极活性材料团聚、堵塞滤网等分散不均匀的现象，提高正极浆料的流动性、过滤性和加工性，通过在正极浆料溶剂中分散和/或悬浮提高浆料的稳定性，降低极片膜层的电阻和提高电池安全性。
在一些实施方式中，所述应用包括上述含氟聚合物或上述方法制备的含氟聚合物在作为电池浆料分散剂中的应用，可以提高电池浆料的稳定性。在一些实施方式中，上述含氟聚合物或上述方法制备的含氟聚合物作为分散剂用于电池正极浆料。在一些实施方式中，上述含氟聚合物或上述方法制备的含氟聚合物作为分散剂用于电池负极浆料。
在一些实施方式中，所述应用包括上述含氟聚合物或上述方法制备的含氟聚合物在改善电池浆料分散性中的应用。所述电池浆料为正极浆料或负极浆料。
另外，以下适当参照附图对本申请的二次电池、电池模块、电池包和用电装置进行说明。
本申请的一个实施方式中，提供一种二次电池。
通常情况下，二次电池包括正极极片、负极极片、电解质和隔离膜。在电池充放电过程中，活性离子在正极极片和负极极片之间往返嵌入和脱出。电解质在正极极片和负极极片之间起到传导离子的作用。隔离膜设置在正极极片和负极极片之间，主要起到防止正 负极短路的作用，同时可以使离子通过。
[正极极片]
正极极片包括正极集流体以及设置在正极集流体至少一个表面的正极膜层，所述正极膜层包括正极活性材料。
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，正极膜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，所述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，正极活性材料可采用本领域公知的用于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LiCoO 2)、锂镍氧化物(如LiNiO 2)、锂锰氧化物(如LiMnO 2、LiMn 2O 4)、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LiNi 1/3Co 1/3Mn 1/3O 2(也可以简称为NCM 333)、LiNi 0.5Co 0.2Mn 0.3O 2(也可以简称为NCM 523)、LiNi 0.5Co 0.25Mn 0.25O 2(也可以简称为NCM 211)、LiNi 0.6Co 0.2Mn 0.2O 2(也可以简称为NCM 622)、LiNi 0.8Co 0.1Mn 0.1O 2(也可以简称为NCM 811)、锂镍钴铝氧化物(如LiNi 0.85Co 0.15Al 0.05O 2)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LiFePO 4(也可以 简称为LFP))、磷酸铁锂与碳的复合材料、磷酸锰锂(如LiMnPO 4)、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，正极膜层还可选地包括粘结剂。作为示例，所述粘结剂可以包括聚偏氟乙烯(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(HFP)-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。
在一些实施方式中，正极膜层还可选地包括导电剂。作为示例，所述导电剂可以包括超导碳、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，可以通过以下方式制备正极极片：将上述用于制备正极极片的组分，例如正极活性材料、导电剂、粘结剂和任意其他的组分分散于溶剂(例如N-甲基吡咯烷酮)中，形成正极浆料；将正极浆料涂覆在正极集流体上，经烘干、冷压等工序后，即可得到正极极片。
[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。
[隔离膜]
在一些实施方式中，二次电池中还包括隔离膜。本申请对隔离膜的种类没有特别的限制，可以选用任意公知的具有良好的化学稳定性和机械稳定性的多孔结构隔离膜。
在一些实施方式中，隔离膜的材质可选自玻璃纤维、无纺布、聚乙烯、聚丙烯及聚偏二氟乙烯中的至少一种。隔离膜可以是单层薄膜，也可以是多层复合薄膜，没有特别限制。在隔离膜为多层复合薄膜时，各层的材料可以相同或不同，没有特别限制。
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，二次电池可包括外包装。该外包装可用于封装上述电极组件及电解质。
在一些实施方式中，二次电池的外包装可以是硬壳，例如硬塑料壳、铝壳、钢壳等。二次电池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。
本申请对二次电池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1是作为一个示例的方形结构的二次电池5。
在一些实施方式中，参照图2，外包装可包括壳体51和盖板53。其中，壳体51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51具有与容纳腔连通的开口，盖板53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52。电极组件52封装于所述容纳腔内。电解液浸润于电极组件52中。二次电池5所含电极组件52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，二次电池可以组装成电池模块，电池模块所含二次电池的数量可以为一个或多个，具体数量本领域技术人员可根据电池模块的应用和容量进行选择。
图3是作为一个示例的电池模块4。参照图3，在电池模块4中，多个二次电池5可以是沿电池模块4的长度方向依次排列设置。当然，也可以按照其他任意的方式进行排布。进一步可以通过紧固件将该多个二次电池5进行固定。
可选地，电池模块4还可以包括具有容纳空间的外壳，多个二次电池5容纳于该容纳空间。
在一些实施方式中，上述电池模块还可以组装成电池包，电池包所含电池模块的数量可以为一个或多个，具体数量本领域技术人员可根据电池包的应用和容量进行选择。
图4和图5是作为一个示例的电池包1。参照图4和图5，在电池包1中可以包括电池箱和设置于电池箱中的多个电池模块4。电池箱包括上箱体2和下箱体3，上箱体2能够盖设于下箱体3，并形成用于容纳电池模块4的封闭空间。多个电池模块4可以按照任意的方式排布于电池箱中。
另外，本申请还提供一种用电装置，所述用电装置包括本申请提供的二次电池、电池模块、或电池包中的至少一种。所述二次电池、电池模块、或电池包可以用作所述用电装置的电源，也可以用作所述用电装置的能量存储单元。所述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。
作为所述用电装置，可以根据其使用需求来选择二次电池、电池模块或电池包。图6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二次电池的高功率和高能量密度的需求，可以采用电池包或电池模块。
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，可以采用二次电池作为电源。
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。
实施例1
1)分散剂含氟聚合物的制备
在1L的四口烧瓶加入0.4kg的去离子水和0.2g的羧乙基纤维素醚，通入氮气去除溶液中溶解的氧，再次加入1.0g 2-乙基过氧化二碳酸酯和0.1g的碳酸氢钠，并充入0.1Kg的偏氟乙烯混合搅拌30min，升温到68℃，进行聚合反应3h；聚合溶液经蒸馏、洗涤、分离、干燥、粉碎即得到聚偏氟乙烯分散剂。
2)正极极片的制备
将正极活性材料磷酸铁锂(LFP)、导电剂碳黑、粘结剂和实施例1中制备的分散剂按照92:4:3.95:0.05的重量比，加入N-甲基吡咯烷酮搅拌混合均匀，得到固含量为58％的正极浆料。将正极浆料均匀涂覆在铝箔正极集流体的两个表面上，然后干燥，得到膜层；之后经过冷压、分切，得到正极极片。其中，粘结剂为重均分子量为70万的PVDF购自阿科玛法国有限公司。
3)负极极片的制备
将负极活性材料人造石墨、导电剂碳黑、粘结剂丁苯橡胶(SBR)、增稠剂羟甲基纤维素钠(CMC)按照重量比为96.2：0.8：0.8：1.2溶于溶剂去离子水中，混合均匀后制备成负极浆料；将负极浆料多次均匀涂覆在负极集流体铜箔的两个表面上，经过烘干、冷压、分切得到负极极片。
4)隔离膜
以聚丙烯膜作为隔离膜。
5)电解液的制备
在氩气气氛手套箱中(H 2O<0.1ppm，O 2<0.1ppm)，将有机溶剂碳酸乙烯酯(EC)和碳酸甲乙酯(EMC)按照体积比3/7混合均匀，将LiPF 6锂盐溶解于有机溶剂中配置成12.5％溶液，得到电解液。
6)电池的制备
将实施例1制备的正极极片、隔离膜、负极极片按顺序叠好，使隔离膜处于正、负极片之间起到隔离的作用，然后卷绕得到裸电芯，给裸电芯焊接极耳，并将裸电芯装入铝壳中，并在80℃下烘烤除水，随即注入电解液并封口，得到不带电的电池。不带电的电池再依次经过静置、热冷压、化成、整形、容量测试等工序，获得实施例1的锂离子电池产品。
实施例2～24的电池和对比例1～7的电池与实施例1的电池制备步骤相同，但是调整了粘结剂、分散剂以及正极材料的用量，不同的参数详见表1和表2。
具体地：
实施例2～7中，电池的制备方法与实施例1一致，区别在于控制粘结剂与分散剂在正极极片中的质量含量为4％，调整二者的质量比，具体参数如表1和表2所示。
实施例8中，电池的制备方法与实施例3保持一致，区别在于分散剂使用重均分子量为0.5万的PVDF聚合物。重均分子量为0.5万的PVDF聚合物的制备方法为：
在1L的四口烧瓶中加入0.4kg的去离子水和0.2g的羧乙基纤维素醚，通入氮气去除溶液中溶解的氧，再次加入1.2g 2-乙基过氧化二碳酸酯和0.1g的碳酸氢钠，并充入0.1Kg的偏氟乙烯，混合搅拌30min，升温到73℃，进行聚合反应2h；聚合溶液经蒸馏、洗涤、分离、干燥、粉碎即得。
实施例9中，电池的制备方法与实施例3保持一致，区别在于分散剂使用重均分子量为2万的PVDF聚合物。重均分子量为2万的PVDF聚合物的制备方法为：
在1L的四口烧瓶中加入0.4kg的去离子水和0.2g的羧乙基纤维素醚，通入氮气去除溶液中溶解的氧，再次加入0.9g 2-乙基过氧化二碳酸酯和0.1g的碳酸氢钠，并充入0.1Kg的偏氟乙烯，混合搅拌30min，升温到66℃，进行聚合反应4h；聚合溶液经蒸馏、洗涤、分离、干燥、粉碎即得。
实施例10～13中，电池的制备方法与实施例3保持一致，区别在于：粘结剂的重均分子量为90万；正极活性材料为锂镍钴锰氧化物NCM，其余参数如表1和表2所示。
调整了粘结剂的重均分子量为90万，其他参数见表1和表2，电池制备方法与实施例3基本一致，除了相关质量配比有所调整。
实施例14中，电池的制备方法与实施例3保持一致，区别在于：粘结剂的重均分子量为110万；正极活性材料为锂镍钴锰氧化物NCM：导电剂：粘结剂：分散剂的质量比为95:3:1.95:0.05。其中，重均分子量为110万的粘结剂PVD购自苏威(上海)有限公司。
实施例15-17中，电池的制备方法与实施例14一致，区别在于控制粘结剂与分散剂在正极极片中的质量含量为2％，调整二者的质量比，具体参数如表1和表2所示。
实施例18中，电池的制备方法与实施例15一致，区别在于分散剂的制备方法与实施例8中分散剂的制备方法相同，重均分子量为0.5万。
实施例19中，电池的制备方法与实施例15一致，区别在于分散剂的制备方法与实施例9中分散剂的制备方法相同，重均分子量为2万。
实施例20中，分散剂使用重均分子量1万的PTFE聚合物，其制备方法为：
在1L的四口烧瓶中加入0.4kg的去离子水和0.2g的羧乙基纤维素醚，通入氮气去除溶液中溶解的氧，再次加入1.0g过氧化叔戊基新戊酸酯和0.1g的碳酸钾，充入0.1Kg的四氟乙烯，混合搅拌30min，升温到68℃，进行聚合反应3h；聚合溶液经蒸馏、洗涤、分离、干燥、粉碎即得到聚四氟乙烯。
实施例21中，分散剂使用重均分子量1万的聚三氟氯乙烯，其制备方法为：
在1L的四口烧瓶中加入0.4kg的去离子水和0.2g的羧乙基纤维素醚，通入氮气去除溶液中溶解的氧，再次加入1.0g过硫酸钾和0.1g的碳酸钾，缓慢充入0.1Kg的三氟氯乙烯，混合搅拌30min，升温到35℃，进行聚合反应3h；聚合溶液经蒸馏、洗涤、分离、干燥、粉碎即得到聚三氟氯乙烯，反应完成后，利用F2/N2混合气体对得到的聚三氟氯乙烯粉末进行氟化封端处理，得到稳定性高的聚三氟氯乙烯。
实施例22中，分散剂使用重均分子量1万的PVDF-HFP(偏氟乙烯-六氟丙烯)聚合物，其制备方法为：
在1L的四口烧瓶中加入0.4kg的去离子水和0.2g的羧乙基纤维素醚，通入氮气去除溶液中溶解的氧，再次加入1.0g过氧化叔戊基 新戊酸酯和0.1g的碳酸钾，充入0.8Kg的偏氟乙烯、0.2Kg六氟丙烯，混合搅拌30min，升温到68℃，进行聚合反应4h；聚合溶液经蒸馏、洗涤、分离、干燥、粉碎即得到聚偏氟乙烯-六氟丙烯。
实施例23和24中分散剂的制备方法与实施例22基本相似，区别在于将共聚单体分别换位四氟乙烯和三氟氯乙烯。对比例1中仅使用重均分子量为70万的PVDF粘结剂制备电池，其他步骤与实施例1相同。
对比例2中仅使用重均分子量为110万的PVDF粘结剂制备电池，其他步骤与实施例10相同。
对比例3中制备方法与实施例3基本一致，区别在于：分散剂使用重均分子量为3万的PVDF聚合物，其制备方法为：
在1L的四口烧瓶中加入0.4kg的去离子水和0.2g的羧乙基纤维素醚，通入氮气去除溶液中溶解的氧，再次加入0.9g 2-乙基过氧化二碳酸酯和0.1g的碳酸氢钠，并充入0.1Kg的偏氟乙烯，混合搅拌30min，升温到66℃，进行聚合反应5h；聚合溶液经蒸馏、洗涤、分离、干燥、粉碎即得到聚偏氟乙烯。
对比例4中使用重均分子量为3万的PVDF聚合物作分散剂，其余步骤与实施例11相同。
对比例5中使用重均分子量为1万的聚乙烯吡咯烷酮为分散剂，其余步骤与实施例1相同。
对比例6中使用重均分子量为1万的顺丁烯二酸酐为分散剂，其余步骤与实施例10相同。
对比例7中使用重均分子量为15万的PVDF作为分散剂。
上述实施例1～24和对比例1～7的分散剂、正极材料的相关参数如下表1和表2所示。对实施例1～24和对比例1～7中得到的分散剂、正极浆料、极片和电池进行性能测试，测试方法如下：
聚合物、极片和电池性能测定
1、重均分子量测试方法
采用Waters 2695 Isocratic HPLC型凝胶色谱仪(示差折光检测器 2141)。质量分数为3.0％的聚苯乙烯溶液试样做参比，选择匹配的色谱柱(油性：Styragel HT5 DMF7.8*300mm+Styragel HT4)。用纯化后的N-甲基吡咯烷酮(NMP)溶剂配置3.0％的待测聚合物胶液，配置好的溶液静置一天，备用。测试时，先用注射器吸取四氢呋喃，进行冲洗，重复几次。然后吸取5ml实验溶液，排除注射器中的空气，将针尖擦干。最后将试样溶液缓缓注入进样口。待示数稳定后获取数据。
2、分散剂含氟聚合物中值粒径Dv50测定
参照GB/T 19077-2016粒度分布激光衍射法，用50mL烧杯称量0.1g～0.13g待测聚合物样品，加入5g无水乙醇，放入约2.5mm搅拌子后用保鲜膜密封。样品超声处理5min后转移到磁力搅拌机，500转/分钟搅拌20min以上，每批次产品抽取2个样品测试。采用英国马尔文仪器有限公司的Mastersizer 2000E型激光粒度分析仪进行测试。
3、粘度测试
将分散剂含氟聚合物溶解于N-甲基吡咯烷酮(NMP)溶剂中，配置固含量为7％的胶液，选取合适的转子，固定好粘度计转子，将胶液放置于粘度计转子下方，胶液恰好淹没转子的刻度线，仪器型号：上海方瑞NDJ-5S，转子：61#(0-500mPa·s)、62#(500-2500mPa·s)、63#(2500-10000mPa·s)、64#(10000-50000mPa·s)，转速：12r/min，测试温度：25℃，测试时间为5min，待示数稳定读取数据。
4、浆料固含量测试
固含量测试方法：准备一个玻璃培养皿并记录重量m 1,取一部分制得的正极浆料放到玻璃培养皿中并记录总重量m 2，将装有正极浆料的培养皿放到干燥箱中加热，加热温度120℃，加热时间1h。将干燥后的培养皿称取并记录重量m 3，按照下式计算：
固含量＝(m 3-m 1)/(m 2-m 1)×100％
5、浆料流动性测试
用药匙取适量正极浆料，观察正极浆料的自然下流是否流畅。若自然下流顺畅判定为OK；若流动性不好，浆料出现果冻状，成块，表明出现凝胶，判定为NG。
6、浆料粘度测试
使用旋转粘度剂测量浆料的粘度。选取合适的转子，固定好粘度计转子，将正极浆料放置于粘度计转子下方，浆料恰好淹没转子的刻度线，仪器型号：上海方瑞NDJ-5S，转子：63#(2000-10000mPa·s)、64#(10000-50000mPa·s)，转速：12r/min，测试温度：25℃，测试时间为5min，待示数稳定读取数据。
7、浆料过滤性能测试
取500ml烧杯置于200目滤网支架下端，取浆料500ml,置于滤网中过滤，记录烧杯中浆料体积到达300ml时的时间，此时间用于判段浆料的过滤性能，过滤时间低于120s，表明浆料的过滤性能OK；若浆料不能透过滤网，表明浆料的过滤性能差，判定为“NG”。
8、电池直流阻抗测定：
正极活性材料为磷酸铁锂时，电池直流阻抗测定方法如下：
以实施例1为例，电池直流阻抗DCR测试过程如下：在25℃下，将实施例1对应的电池，以1/3C恒流充电至3.65V，再以3.65V恒定电压充电至电流为0.05C，搁置5min后，记录电压V1。然后再以1/3C放电30s，记录电压V2，则(V2-V1)/1/3C，得到第一次循环后电池的内阻DCR1。对上述同一个电池重复以上步骤，并同时记录循环第n次后电池的内阻DCRn(n＝1、2、3……100)，将上述DCR1、DCR2、DCR3……DCR100这100个点值为纵坐标，以对应的循环次数为横坐标,得到相应的图谱。
该测试过程中，第一次循环对应n＝1、第二次循环对应n＝2、……第500次循环对应n＝500。表2中实施例1的电池直流阻抗增大比率按照以下公式计算：
电池直流阻抗增大比率＝(DCRn-DCR1)/DCR1×100％
对比例1以及其他实施例的测试过程同上。表2中的数据是在上 述测试条件下循环500次之后测得的数据。
正极活性材料为锂镍钴锰氧化物NCM时，测定方法如下：
以实施例10为例，电池直流阻抗DCR测试过程如下：在25℃下，将实施例10对应的电池，以1/3C恒流充电至4.4V，再以4.4V恒定电压充电至电流为0.05C，搁置5min后，记录电压V1。然后再以1/3C放电30s，记录电压V2，则(V2-V1)/1/3C，得到第一次循环后电池的内阻DCR1。其他步骤与磷酸铁锂正极活性材料的电池直流阻抗DCR测试方法相同。
9、粘结力的测定：
参考国标GBT 2790-1995《胶粘剂180°剥离强度实验方法》，本申请实施例和对比例的粘结力测试过程如下：
用刀片截取宽30mm、长度为100-160mm的极片试样，将专用双面胶贴于钢板上，胶带宽度20mm、长度90-150mm。将前面截取的极片试样贴在双面胶上，测试面朝下，后用压辊沿同一个方向滚压三次。将宽度与极片试样等宽，长度为250mm的纸带固定于极片集流体下方，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，将钢板未贴极片试样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。将极片受力平衡时的力除以胶带的宽度作为单位长度的极片的粘结力，以表征正极膜层与集流体之间的粘结强度。
测试结果
表1
Figure PCTCN2023071658-appb-000005
Figure PCTCN2023071658-appb-000006
Figure PCTCN2023071658-appb-000007
表2
Figure PCTCN2023071658-appb-000008
Figure PCTCN2023071658-appb-000009
实施例1-24和对比例1-7的性能测试结果如表1和表2所示。
根据上述结果可知，对比例1中仅使用重均分子量为70万的PVDF粘结剂制备正极浆料，浆料的流动性、浆料粘度和过滤性差，使得正极浆料分散不均匀和加工性差，难以生产高质量正极极片。
对比例2中仅使用重均分子量为110万的PVDF粘结剂制备正极浆料，正极浆料中的正极活性材料容易出现团聚，使得正极浆料分散不均匀，导致浆料的流动性、浆料粘度和过滤性差，进而使得直流阻抗增长率增加。
实施例1～实施例24中使用重均分子量为0.5万～2万的含氟聚合物和重均分子量为70万～110万的PVDF粘结剂制备正极浆料，其中分散剂的质量含量为0.05％～0.7％，粘结剂的质量含量为1.4％～4％，制得的正极浆料的粘度为2000～50000mPa·s。从实施例1～实施例24和对比例1～对比例2的对比可见，重均分子量为0.5万～2万的含氟聚合物在正极浆料中作为分散剂取得了良好的效果，改善了正极浆料的流动性和过滤性，提高了正极浆料的稳定性和加工性，同时不会大幅度降低极片的粘结力，有利于降低极片的直流阻抗增长率。
对比例5和对比例6分别使用不同种类的分散剂与PVDF粘结剂制备正极浆料，正极浆料的过滤速度慢且有滤渣，浆料分散性差，导致正极极片的直流阻抗增长率增加。实施例1、实施例10与对比例5、对比例6相比，在过滤性能方面显著改善，正极浆料的加工性提高并降低了极片的直流阻抗增长率，且在粘结性能方面，极片具有更好的粘结力。
实施例1～实施例9使用重均分子量为0.5万～2万、中值粒径Dv50为0.5～1μm、粘度为20～50mPa·s的分散剂与重均分子量为70万的PVDF粘结剂制备正极浆料。相较使用重均分子量为3万、中 值粒径Dv50为1.3μm、粘度为60mPa·s的分散剂与重均分子量为70万的PVDF粘结剂制备正极浆料的对比例3而言，在正极浆料的流动性、粘度和过滤性能方面具有明显提高，由于正极浆料的分散性改善，进而提高了正极浆料的稳定性和加工性。
实施例14～实施例19使用重均分子量为0.5万～2万、中值粒径Dv50为0.5～1μm、粘度为20～50mPa·s的分散剂与重均分子量为110的PVDF粘结剂制备正极浆料。与使用重均分子量为3万、中值粒径Dv50为1.3μm、粘度为20～60mPa·s的分散剂与重均分子量为110万的PVDF粘结剂制备正极浆料的对比例4相比，在正极浆料的流动性、粘度和过滤性能方面具有明显提高，并且改善了极片的直流阻抗增长率。
需要说明的是，本申请不限定于上述实施方式。上述实施方式仅为示例，在本申请的技术方案范围内具有与技术思想实质相同的构成、发挥相同作用效果的实施方式均包含在本申请的技术范围内。此外，在不脱离本申请主旨的范围内，对实施方式施加本领域技术人员能够想到的各种变形、将实施方式中的一部分构成要素加以组合而构筑的其它方式也包含在本申请的范围内。

Claims (24)

  1. 一种用于二次电池极片的分散剂，其特征在于，所述分散剂为含有式I所示结构单元的含氟聚合物，且所述含氟聚合物的重均分子量小于等于2万，
    Figure PCTCN2023071658-appb-100001
    其中，R 1、R 2各自独立地选自氢、氟、氯或三氟甲基。
  2. 根据权利要求1所述的分散剂，其特征在于，R 1选自氢、氟或三氟甲基，且R 2选自氢、氟、氯或三氟甲基，或者R 1选自氢、氟、氯或三氟甲基，且R 2选自氢、氟或三氟甲基。
  3. 根据权利要求1或2所述的分散剂，其特征在于，所述含氟聚合物的重均分子量为0.5万～2万。
  4. 根据权利要求1至3中任一项所述的分散剂，其特征在于，所述含氟聚合物为氟代烃聚合物，选自聚四氟乙烯、聚偏二氟乙烯、偏二氟乙烯和六氟丙烯的共聚物中的一种或多种。
  5. 根据权利要求1至4中任一项所述的分散剂，其特征在于，所述含氟聚合物的颗粒的中值粒径Dv50为0.5～1μm。
  6. 根据权利要求1至5中任一项所述的分散剂，其特征在于，所述含氟聚合物溶于N-甲基吡咯烷酮制得胶液，当所述胶液中所述聚合物的质量百分含量为7％时，所述胶液的粘度为20～50mPa·s。
  7. 一种粘结剂组合物，包含粘结剂和权利要求1至6中任一项所述的分散剂。
  8. 根据权利要求7所述的粘结剂组合物，其特征在于，在所述粘结剂组合物中，所述粘结剂为重均分子量为70万～110万的聚偏二氟乙烯或其改性聚合物。
  9. 根据权利要求7或8所述的粘结剂组合物，其特征在于，所述分散剂和所述粘结剂的质量比为1:80～1:2。
  10. 根据权利要求7至9中任一项所述的粘结剂组合物，其特征在于，所述分散剂和所述粘结剂的质量比为1:40～1:4。
  11. 一种分散剂的制备方法，其特征在于，所述分散剂为含氟聚合物，
    提供至少一种式II所示单体，
    Figure PCTCN2023071658-appb-100002
    其中，R 1、R 2各自独立地选自氢、氟、氯、三氟甲基中的一种或多种；
    在可聚合条件下聚合所述单体制备含氟聚合物，所述含氟聚合物的重均分子量小于等于2万。
  12. 根据权利要求11所述的分散剂的制备方法，其特征在于，所述含氟聚合物的重均分子量为0.5万～2万。
  13. 根据权利要求11或12所述的分散剂的制备方法，其特征在于，还包括以下步骤：
    将至少一种式II所示单体在非反应性气体氛围、常压、60℃～80℃的反应温度下进行聚合反应2小时～5小时，停止反应，固液分离，保留固相。
  14. 根据权利要求11至13中任一项所述的分散剂的制备方法，其特征在于，还包括以下步骤：
    向容器中加入溶剂和分散助剂，对所述容器充入非反应性气体；
    向所述容器中加入引发剂和pH调节剂，调节pH值至6.5～7，然后加入式II所示单体，搅拌0.5小时～1小时后，升温至60℃～80℃，进行聚合反应。
  15. 一种正极浆料，其特征在于，所述正极浆料中包括权利要求7至10中任一项所述的粘结剂组合物。
  16. 根据权利要求15所述的正极浆料，其特征在于，所述正极浆料在N-甲基吡咯烷酮中的固含量为58％时，所述正极浆料的粘度为2000～50000mPa·s。
  17. 根据权利要求15或16所述的正极浆料，其特征在于，所述分散剂的质量含量为0.05％～0.7％，基于所述正极浆料中固体物质的总质量计。
  18. 根据权利要求15至17中任一项所述的正极浆料，其特征在于，所述正极浆料中所述粘结剂的质量含量为1.4％～4％，基于所述正极浆料中固体物质的总质量计。
  19. 根据权利要求15至18中任一项所述的正极浆料，其特征在于，所述正极浆料中包含正极活性材料，所述正极活性材料为含锂的过渡金属氧化物。
  20. 根据权利要求19所述的正极浆料，其特征在于，所述含锂的过渡金属氧化物为磷酸铁锂或锂镍钴锰氧化物，或它们的掺杂改性材料、或它们的导电碳包覆改性材料、导电金属包覆改性材料或导电聚合物包覆改性材料中的至少一种。
  21. 一种二次电池，其特征在于，包括正极极片、隔离膜、负极极片以及电解液，所述正极极片由权利要求15至20中任一项所述的正极浆料制备而得。
  22. 一种电池模块，其特征在于，包括权利要求21所述的二次电池。
  23. 一种电池包，其特征在于，包括权利要求22所述的电池模块。
  24. 一种用电装置，其特征在于，包括选自权利要求21所述的二次电池、权利要求22所述的电池模块或权利要求23所述的电池包中的至少一种。
PCT/CN2023/071658 2022-08-30 2023-01-10 分散剂、粘结剂组合物、正极浆料、二次电池、电池模块、电池包及用电装置 WO2024045472A1 (zh)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202211044631.4 2022-08-30
CN202211044631.4A CN115117358B (zh) 2022-08-30 2022-08-30 含氟聚合物、其制备方法和用途、正极浆料、二次电池、电池模块、电池包及用电装置

Publications (1)

Publication Number Publication Date
WO2024045472A1 true WO2024045472A1 (zh) 2024-03-07

Family

ID=83336042

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2023/071658 WO2024045472A1 (zh) 2022-08-30 2023-01-10 分散剂、粘结剂组合物、正极浆料、二次电池、电池模块、电池包及用电装置

Country Status (2)

Country Link
CN (2) CN115117358B (zh)
WO (1) WO2024045472A1 (zh)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115117358B (zh) * 2022-08-30 2023-02-03 宁德时代新能源科技股份有限公司 含氟聚合物、其制备方法和用途、正极浆料、二次电池、电池模块、电池包及用电装置
CN117801295A (zh) * 2022-09-30 2024-04-02 宁德时代新能源科技股份有限公司 Bab型嵌段共聚物、制备方法、粘结剂、正极浆料、正极极片、二次电池及用电装置

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004079327A (ja) * 2002-08-16 2004-03-11 Hitachi Maxell Ltd 非水二次電池および非水二次電池用正極とその製造方法
CN101241988A (zh) * 2008-02-03 2008-08-13 深圳市比克电池有限公司 一种锂离子电池正极极片的制作方法
CN101265397A (zh) * 2008-04-14 2008-09-17 东莞市迈科新能源有限公司 一种粘结剂及应用该粘结剂的锂离子电池
CN101460558A (zh) * 2006-04-14 2009-06-17 阿克马法国公司 基于聚偏氟乙烯的导电组合物
CN102473906A (zh) * 2009-07-01 2012-05-23 大金工业株式会社 储氢合金电极和镍氢电池
CN102598375A (zh) * 2009-11-06 2012-07-18 旭硝子株式会社 二次电池用粘合剂组合物、使用其的二次电池用电极合剂以及二次电池
CN115117358A (zh) * 2022-08-30 2022-09-27 宁德时代新能源科技股份有限公司 含氟聚合物、其制备方法和用途、正极浆料、二次电池、电池模块、电池包及用电装置
CN115133035A (zh) * 2022-08-30 2022-09-30 宁德时代新能源科技股份有限公司 正极浆料及其制备方法、二次电池、电池模块、电池包和用电装置

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4546053B2 (ja) * 2003-08-06 2010-09-15 パナソニック株式会社 非水電解質二次電池用正極板および非水電解質二次電池
CN101740747B (zh) * 2008-11-27 2012-09-05 比亚迪股份有限公司 一种硅负极和含有该硅负极的锂离子电池
CN112062905A (zh) * 2019-06-10 2020-12-11 比亚迪股份有限公司 聚合物固态电解质及其聚合物基材和组合物以及电池

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004079327A (ja) * 2002-08-16 2004-03-11 Hitachi Maxell Ltd 非水二次電池および非水二次電池用正極とその製造方法
CN101460558A (zh) * 2006-04-14 2009-06-17 阿克马法国公司 基于聚偏氟乙烯的导电组合物
CN101241988A (zh) * 2008-02-03 2008-08-13 深圳市比克电池有限公司 一种锂离子电池正极极片的制作方法
CN101265397A (zh) * 2008-04-14 2008-09-17 东莞市迈科新能源有限公司 一种粘结剂及应用该粘结剂的锂离子电池
CN102473906A (zh) * 2009-07-01 2012-05-23 大金工业株式会社 储氢合金电极和镍氢电池
CN102598375A (zh) * 2009-11-06 2012-07-18 旭硝子株式会社 二次电池用粘合剂组合物、使用其的二次电池用电极合剂以及二次电池
CN115117358A (zh) * 2022-08-30 2022-09-27 宁德时代新能源科技股份有限公司 含氟聚合物、其制备方法和用途、正极浆料、二次电池、电池模块、电池包及用电装置
CN115133035A (zh) * 2022-08-30 2022-09-30 宁德时代新能源科技股份有限公司 正极浆料及其制备方法、二次电池、电池模块、电池包和用电装置

Also Published As

Publication number Publication date
CN117624418A (zh) 2024-03-01
CN115117358B (zh) 2023-02-03
CN115117358A (zh) 2022-09-27

Similar Documents

Publication Publication Date Title
WO2024045472A1 (zh) 分散剂、粘结剂组合物、正极浆料、二次电池、电池模块、电池包及用电装置
WO2024045505A1 (zh) 粘结剂组合物、正极浆料、二次电池、电池模块、电池包和用电装置
WO2024045471A1 (zh) 核壳结构聚合物、制备方法和用途、正极浆料、二次电池、电池模块、电池包和用电装置
WO2024045554A1 (zh) 粘结剂、制备方法、正极极片、二次电池及用电装置
WO2024045553A1 (zh) 粘结剂、制备方法、正极极片、二次电池及用电装置
WO2024066504A1 (zh) 粘结剂、制备方法、正极极片、二次电池及用电装置
WO2024045619A1 (zh) 粘结剂、制备方法、正极极片、二次电池及用电装置
WO2024045644A1 (zh) 含氟聚合物、其制备方法和用途，粘结剂组合物、二次电池及用电装置
WO2024045506A1 (zh) 粘结剂、制备方法、正极极片、二次电池及用电装置
WO2024045504A1 (zh) 粘结剂、制备方法、正极极片、二次电池及用电装置
WO2024021018A1 (zh) 干法电极用底涂胶及其制备方法、复合集流体、电池极片、二次电池、电池模块、电池包和用电装置
WO2023236160A1 (zh) 正极浆料、二次电池、电池模块、电池包及用电装置
WO2023241200A1 (zh) 粘结剂组合物、正极极片、二次电池及用电装置
WO2024045631A1 (zh) 粘结剂组合物、正极极片、二次电池及用电装置
WO2024092808A1 (zh) 核壳结构聚合物、水性底涂浆料、二次电池、用电装置
WO2024092789A1 (zh) 核壳结构聚合物、导电浆料、二次电池及用电装置
WO2023230930A1 (zh) 粘结剂、制备方法、二次电池、电池模块、电池包及用电装置
WO2023230895A1 (zh) 粘结剂组合物、二次电池、电池模块、电池包及用电装置
WO2023241201A1 (zh) 粘结剂组合物、正极极片、二次电池及用电装置
WO2023240543A1 (zh) 粘结剂及其制备方法与应用
WO2024092813A1 (zh) 含氟聚合物、导电浆料、正极极片、二次电池、用电装置
WO2024146323A1 (zh) 含氟聚合物、其制备方法和应用、绝缘浆料、绝缘涂层、二次电池及用电装置
WO2024092809A1 (zh) 含氟聚合物、底涂浆料、二次电池、及用电装置
WO2023097431A1 (zh) 含氟共聚物及包含其的二次电池
WO2024092783A1 (zh) 含氟聚合物、制备方法、绝缘涂层、二次电池、用电装置

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 23858515

Country of ref document: EP

Kind code of ref document: A1