WO2023044753A1 - 电解液、二次电池、电池模块、电池包和用电装置 - Google Patents

电解液、二次电池、电池模块、电池包和用电装置 Download PDF

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WO2023044753A1
WO2023044753A1 PCT/CN2021/120318 CN2021120318W WO2023044753A1 WO 2023044753 A1 WO2023044753 A1 WO 2023044753A1 CN 2021120318 W CN2021120318 W CN 2021120318W WO 2023044753 A1 WO2023044753 A1 WO 2023044753A1
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Prior art keywords
diisocyanate
electrolyte
secondary battery
negative electrode
positive electrode
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PCT/CN2021/120318
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English (en)
French (fr)
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彭畅
陈培培
邹海林
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宁德时代新能源科技股份有限公司
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Priority to PCT/CN2021/120318 priority Critical patent/WO2023044753A1/zh
Priority to JP2022557174A priority patent/JP2023547001A/ja
Priority to KR1020227032148A priority patent/KR20230044353A/ko
Priority to EP21927058.4A priority patent/EP4184648A4/en
Priority to CN202180088019.4A priority patent/CN116648806A/zh
Priority to US17/981,325 priority patent/US20230094322A1/en
Publication of WO2023044753A1 publication Critical patent/WO2023044753A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0567—Liquid materials characterised by the additives
    • 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
    • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
    • 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
    • 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
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0568—Liquid materials characterised by the solutes
    • 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
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0569—Liquid materials characterised by the solvents
    • 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
    • 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
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    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
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    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • H—ELECTRICITY
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    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00—Batteries for particular applications
    • H01M2220/20—Batteries in motive systems, e.g. vehicle, ship, plane
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • H01M2300/0028—Organic electrolyte characterised by the solvent
    • H01M2300/0034—Fluorinated solvents
    • H—ELECTRICITY
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    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • H01M2300/0028—Organic electrolyte characterised by the solvent
    • H01M2300/0037—Mixture of solvents
    • H—ELECTRICITY
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    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • H01M2300/0028—Organic electrolyte characterised by the solvent
    • H01M2300/0037—Mixture of solvents
    • H01M2300/004—Three solvents
    • H—ELECTRICITY
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    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
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    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/136—Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application relates to the technical field of lithium batteries, in particular to an electrolyte, a secondary battery containing it, a battery module, a battery pack and an electrical device.
  • lithium-ion batteries have been widely used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, as well as power tools, electric bicycles, electric motorcycles, electric vehicles, Military equipment, aerospace and other fields. Due to the great development of lithium-ion batteries, higher requirements have been put forward for their energy density, cycle performance and safety performance.
  • the present application was made in view of the above-mentioned problems, and an object thereof is to provide an electrolytic solution capable of solving the problem of large cyclic stress caused by cyclic expansion of a high-voltage system.
  • the present application provides an electrolyte, a secondary battery containing it, a battery module, a battery pack and an electrical device.
  • the first aspect of the present application provides a kind of electrolytic solution, described electrolytic solution comprises
  • a titanate with the structural formula Ti-(OR 1 ) 4 wherein said R 1 is selected from C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, C 2 -C 6 alkenyl, C 2 -C One or more of 6 alkynyl groups or C 1 -C 6 silyl groups.
  • the battery using the electrolyte solution of the present application has low cyclic stress and low pole piece expansion under high voltage system cyclic expansion.
  • the fluorine-containing metal salt is one or more selected from MSO 3 F, MPO 2 F 2 ;
  • M is a metal ion, which can be Li, Na, K or Cs One of.
  • the fluorine-containing metal salt is one or more selected from LiSO 3 F and LiPO 2 F 2 .
  • the titanate is one or more selected from the following:
  • the molar ratio of the titanate to the fluorine-containing metal salt is 2/1 ⁇ 1/20, optionally 1/8 ⁇ 1/10.
  • the electrode plate expansion force of the battery using the electrolyte of the present application is smaller, and the cycle stress is smaller.
  • the fluorine-containing metal salt accounts for 0.01% to 8% of the mass of the electrolyte, optionally 0.1% to 5%, and further optionally 0.2% to 3%;
  • the titanic acid The ester accounts for 0.01% to 8% of the mass of the electrolyte, may be 0.1% to 5%, and further may be 0.15% to 2.5%.
  • the sum of the fluorine-containing metal salt and the titanate accounts for 0.01% to 10% of the mass of the electrolyte, optionally 0.1% to 8%, and further optionally 0.2% to 4%.
  • the electrolyte also includes a fluorinated solvent, and the fluorinated solvent is selected from one or more of fluorocarbonate, fluorobenzene, and fluoroether; optionally, the Said fluorocarbonate is selected from At least one of, and/or, the fluorobenzene is And/or, the fluoroether is Wherein, R 2 , R 3 , R 4 , R 5 are each independently selected from C 1 -C 6 alkyl, C 1 -C 6 fluoroalkyl, R 6 , R 7 are each independently selected from C 1 -C 4 alkylene, C 1 -C 4 fluoroalkylene, R 8 , R 9 , R 10 , R 11 , R 12 , R 13 are each independently selected from F or H.
  • the fluorinated solvent is selected from one or more of fluorocarbonate, fluorobenzene, and fluoroether
  • the Said fluorocarbonate is selected from At least one of, and/or,
  • the oxidation potential of the electrolyte can be further increased, the electrochemical window of the electrolyte can be broadened, the oxidative decomposition of the electrolyte can be inhibited, the damage of the SEI and CEI membranes can be reduced, and the expansion of the electrode sheet during the cycle can be reduced. Reduce cyclic expansion stress.
  • the fluorocarbonate is selected from at least one of; and/or, the fluorobenzene is And/or, the fluoroether is selected from at least one of the
  • the fluorinated solvent accounts for 10-70% of the mass of the electrolyte.
  • the second aspect of the present application also provides a secondary battery, including the electrolyte solution according to the first aspect of the present application.
  • the secondary battery includes a positive electrode sheet and a negative electrode sheet
  • the positive electrode sheet includes a positive electrode collector and a positive electrode film layer disposed on at least one surface of the positive electrode collector,
  • the positive electrode film layer contains vinylidene fluoride-alkyl unit-acrylate-acrylic acid copolymer (PVdF-Ac) as a binder.
  • the binder has a structure of general formula (I):
  • R 1 ', R 2 ', R 3 ', R 4 ' are each independently selected from hydrogen, optionally substituted C 1 -C 8 alkyl, wherein the substituent is selected from at least one of F, Cl, Br,
  • R 5 ', R 6 ', R 7 ' are each independently selected from hydrogen, optionally substituted C 1 -C 6 alkyl, wherein the substituent is selected from at least one of F, Cl, Br,
  • R 8 ' is selected from optionally substituted C 1 -C 15 alkyl, wherein the substituent is selected from at least one of F, Cl, Br,
  • R 9 ′, R 10 ′, and R 11 ′ are each independently selected from hydrogen, optionally substituted C 1 -C 6 alkyl, wherein the substituent is selected from at least one of F, Cl, and Br.
  • the positive electrode film layer contains at least one positive electrode active material selected from the following: lithium manganese iron phosphate, lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt Manganese oxides, lithium nickel cobalt aluminum oxides and complexes of the above compounds with other transition metals or non-transition metals.
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode film layer arranged on at least one surface of the negative electrode current collector, and the negative electrode film layer contains epoxy groups or isocyanate groups.
  • group compound when the negative film layer contains a compound with epoxy groups, the compound with epoxy groups contains at least two epoxy groups, and when the negative film layer contains a compound with isocyanate groups, The compound having isocyanate groups contains at least two isocyanate groups.
  • the compound having an epoxy group is selected from bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, pentaerythritol glycidyl ether , 1,4-butanediol glycidyl ether, propylene glycol glycidyl ether, glycidyl phthalate, diglycidyl tetrahydrophthalate, diglycidyl hexahydrophthalate, 4,4' -Diaminodiphenylmethane tetraglycidyl epoxy, triglycidyl p-aminophenol, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, tetraglycidyl-1,3- Bis(aminomethylcyclohexane), 9,9-bis[(2,3-epoxypropoxy)phenyl]fluorene, 1,4
  • the compound with isocyanate group is selected from toluene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, dimethyl biphenyl diisocyanate, hexamethylene diisocyanate, 2,2,4 -Trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, hydrogenated xylylene diisocyanate, isofor Alone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, methylcyclohexane diisocyanate, 1,4-benzenediisocyanate, norbornane diisocyanate one or more.
  • a third aspect of the present application provides a battery module including the secondary battery of the second aspect of the present application.
  • a fourth aspect of the present application provides a battery pack including the secondary battery of the second aspect of the present application or the battery module of the third aspect of the present application.
  • the fifth aspect of the present application provides an electric device, including at least one selected from the secondary battery of the second aspect of the present application, the battery module of the third aspect of the present application, or the battery pack of the fourth aspect of the present application. kind.
  • the battery module, battery pack or electrical device of the present application includes the secondary battery according to the second aspect of the present application, and therefore has at least the same advantages as the secondary battery described in the second aspect of the present application.
  • FIG. 1 is a schematic diagram of a secondary battery according to an embodiment of the present application.
  • FIG. 2 is an exploded view of the secondary battery according to one embodiment of the present application shown in FIG. 1 .
  • FIG. 3 is a schematic diagram of a battery module according to an embodiment of the present application.
  • FIG. 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 one embodiment of the present application shown in FIG. 4 .
  • FIG. 6 is a schematic diagram of an electrical device in which a secondary battery is used as a power source according to an embodiment of the present application.
  • ranges disclosed herein are defined in terms of lower and upper limits, and 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 and may be combined arbitrarily, ie any lower limit may be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a particular parameter, it is understood that ranges of 60-110 and 80-120 are contemplated. Additionally, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, the following ranges are all expected: 1-3, 1-4, 1-5, 2- 3, 2-4 and 2-5.
  • the numerical range "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" indicates that all real numbers between "0-5" have been listed in this article, and "0-5" is only an abbreviated representation of the combination of these values.
  • 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 in sequence, and may also include steps (b) and (a) performed in sequence.
  • steps (c) means that step (c) may be added to the method in any order, for example, 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) and so on.
  • the “comprising” and “comprising” mentioned in this application mean open or closed.
  • the “comprising” and “comprising” may mean that other components not listed may be included or included, or only listed components may be included or included.
  • the term "or” is inclusive unless otherwise stated.
  • the phrase "A or B” means “A, B, or both A and B.” More specifically, the condition "A or B” is satisfied by either of the following: 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).
  • halogen halogen atom or halo are understood to mean fluorine, chlorine, bromine and iodine, especially bromine, chlorine or fluorine, preferably chlorine or fluorine, more preferably fluorine.
  • alkyl is understood to mean having the specified number of carbon atoms (eg C 1 -C 8 , one, two, three, four, five, six, seven or eight carbon atoms) straight or branched chain hydrocarbon groups, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, hexyl, heptyl , octyl, 2-methylbutyl, 1-methylbutyl, 1-ethylpropyl, 1,2-dimethylpropyl, neopentyl, 1,1-dimethylpropyl, 4 -Methylpentyl, 3-methylpentyl, 2-methylpentyl, 1-methylpentyl, 2-ethylbutyl, 1-ethylbutyl, 3,3-dimethylbutyl , 2,2-
  • C 1 -C 6 -alkyl is understood to mean straight-chain or branched hydrocarbon radicals having 1, 2, 3, 4, 5 or 6 carbon atoms, for example methyl, ethyl, n-propyl, Isopropyl, n-butyl, tert-butyl, pentyl, isopentyl, hexyl, 2-methylbutyl, 1-methylbutyl, 1-ethylpropyl, 1,2-dimethylpropane Base, neopentyl, 1,1-dimethylpropyl, 4-methylpentyl, 3-methylpentyl, 2-methylpentyl, 1-methylpentyl, 2-ethylbutyl , 1-ethylbutyl, 3,3-dimethylbutyl, 2,2-dimethylbutyl, 1,1-dimethylbutyl, 2,3-dimethylbutyl, 1, 3-Dimethylbutyl or 1,2-dimethylbutyl.
  • C 2 -C 6 -alkenyl is understood to mean a straight-chain or branched monovalent hydrocarbon radical which contains one double bond and has 2, 3, 4, 5 or 6 carbon atoms.
  • the alkenyl group is C 2 -C 3 -alkenyl, C 3 -C 6 -alkenyl or C 3 -C 4 -alkenyl.
  • the alkenyl group is, for example, vinyl, allyl, (E)-2-methylvinyl, (Z)-2-methylvinyl or isopropenyl.
  • C 2 -C 6 -alkynyl is understood to mean a straight-chain or branched monovalent hydrocarbon radical containing one triple bond and comprising 2, 3, 4, 5 or 6 carbon atoms.
  • the alkynyl group is C 2 -C 3 -alkynyl, C 3 -C 6 -alkynyl or C 3 -C 4 -alkynyl.
  • the C 2 -C 3 -alkynyl group is, for example, ethynyl, prop-1-ynyl or prop-2-ynyl.
  • C 1 -C 4 -alkylene is understood to mean having 1 to 4 carbon atoms, especially 2, 3 or 4 carbon atoms (for example in “C 2 -C 4 -alkylene” ), a straight-chain, divalent and saturated hydrocarbon group, such as ethylene, n-propylene, n-butylene, n-pentylene or n-hexylene, preferably n-propylene or n-butylene.
  • C 1 -C 6 -silyl is understood to mean a linear or branched Si-alkyl group comprising 1, 2, 3, 4, 5 or 6 carbon atoms, such as (but not limited to) ) trimethylsilyl, triethylsilyl.
  • Haloalkyl mean alkyl, alkenyl, alkynyl and alkylene, respectively, partially or completely substituted with the same or different halogen atoms
  • Alkyl such as monohaloalkyl, such as CH2CH2Cl, CH2CH2Br , CHClCH3 , CH2Cl , CH2F ; perhaloalkyl, such as CCl3 , CClF2 , CFCl2 , CF2CClF2 , CF 2 CCIFCF 3 ; haloalkyl, for example CH 2 CHFCl, CF 2 CCIFH, CF 2 CBrFH, CH 2 CF 3 ; the term perhaloalkyl also includes the term perfluoroalkyl.
  • C 1 -C 8 should be interpreted as including any subrange therein, such as C 1 -C 8 , C 1 -C 7 , C 1 -C 6 , C 1 -C 5 , C 1 - C 4 , C 1 -C 3 , C 1 -C 2 , C 2 -C 8 , C 2 -C 7 , C 2 -C 6 , C 2 -C 5 , C 2 -C 4 , C 2 -C 3 , C 3 -C 8 , C 3 -C 7 , C 3 -C 6 , C 3 -C 5 , C 3 -C 4 , C 4 -C 8 , C 4 -C 7 , C 4 -C 6 , C 4 -C 5 , C 5 -C 8 , C 5 -C 7 , C 5 -C 6 , C 6 -C 8 , C 6 -C 7 , C 7 -C 8 .
  • C 1 -C 6 should be interpreted to include any subranges therein, such as C 1 -C 6 , C 1 -C 5 , C 1 -C 4 , C 1 -C 3 , C 1 -C 2 , C 2 -C 6 , C 2 -C 5 , C 2 -C 4 , C 2 -C 3 , C 3 -C 6 , C 3 -C 5 , C 3 -C 4 , C 4 -C 6 , C 4 -C 5 , C 5 -C 6 .
  • C 1 -C 4 should be interpreted to include any subranges therein, such as C 1 -C 4 , C 1 -C 3 , C 1 -C 2 , C 2 -C 4 , C 2 -C 3. C 3 -C 4 .
  • C 2 -C 6 should be interpreted to include any subranges therein, such as C 2 -C 5 , C 2 -C 4 , C 2 -C 3 , C 3 -C 4 , C 3 -C 5 , C 3 -C 6 , C 4 -C 5 , C 4 -C 6 , C 5 -C 6 .
  • cathode materials In order to increase the energy density of batteries, increasing the working potential of cathode materials has become the primary strategy for researchers. For example, the operating voltage of conventional ternary cathode materials is increased to above 4.4V, and cathode materials with higher voltage and gram capacity, such as lithium-rich layered cathodes, spinel oxides LiNi 0.5 Mn 1.5 O 4 , etc., have higher operating voltages. The upper voltage limit is close to 5V. The inventors of the present application found that after the voltage is increased, the electrolyte is not resistant to oxidation, resulting in a decrease in the performance of the entire battery.
  • the delithiation amount of the positive electrode material is larger, and the volume of the corresponding positive electrode material and negative electrode material changes greatly.
  • the total volume of the battery cell changes greatly during the charging and discharging process of the battery cell, and the free electrolyte inside the battery cell is squeezed out. Insufficient lithium leads to lithium precipitation.
  • the large cycle expansion of the battery cell will also cause wrinkles on the pole piece of the battery cell. In more serious cases, it will also cause a short circuit of the battery cell, causing safety problems, and greatly affecting the reliability of the battery cell.
  • the inventors of the present application found that when the high-voltage system electrolyte contains the following additives, the cyclic expansion of the battery can be significantly inhibited, and the cyclic expansion stress can be significantly reduced:
  • a titanate with the structural formula Ti-(OR 1 ) 4 wherein said R 1 is selected from C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, C 2 -C 6 alkenyl, C 2 -C One or more of 6 alkynyl groups or C 1 -C 6 silyl groups.
  • the first aspect of the present application provides a kind of electrolytic solution, described electrolytic solution comprises
  • a titanate with the structural formula Ti-(OR 1 ) 4 wherein said R 1 is selected from C 1 -C 6 alkyl, C 1 -C 6 haloalkyl, C 2 -C 6 alkenyl, C 2 -C One or more of 6 alkynyl groups or C 1 -C 6 silyl groups.
  • the inventor unexpectedly found that by adding the above-mentioned additives in the electrolyte, the battery using the electrolyte of the present application has low cycle stress.
  • the electrolyte solution of the present application can form a multi-dimensional network and toughness polymer and inorganic compound SEI film on the positive and negative electrodes, which can significantly reduce the cyclic stress.
  • the fluorine-containing metal salt is one or more selected from MSO 3 F, MPO 2 F 2 ;
  • M is a metal ion, which can be Li, Na, K or Cs One of.
  • the fluorine-containing metal salt is one or more selected from LiSO 3 F and LiPO 2 F 2 .
  • the titanate is one or more selected from the following:
  • the molar ratio of the titanate to the fluorine-containing metal salt is 2/1 ⁇ 1/20, optionally 1/8 ⁇ 1/10.
  • the electrode sheet of the battery using the electrolyte of the present application has less expansion and less cyclic stress.
  • the corresponding SEI film has better binding force to the positive and negative active materials and has better toughness.
  • the molar ratio is too high, the flexibility of the SEI film becomes poor, and the effect of inhibiting cycle expansion is not good.
  • the molar ratio is too low, the SEI film is prone to brittle cracks, which in turn leads to expansion of the pole piece and greater cyclic stress of the cell.
  • the fluorine-containing metal salt accounts for 0.01% to 8% of the mass of the electrolyte, optionally 0.1% to 5%, and further optionally 0.2% to 3%;
  • the titanic acid The ester accounts for 0.01% to 8% of the mass of the electrolyte, may be 0.1% to 5%, and further may be 0.15% to 2.5%.
  • the sum of the fluorine-containing metal salt and the titanate accounts for 0.01% to 10% of the mass of the electrolyte, optionally 0.1% to 8%, and further optionally 0.2% to 8%. 4%.
  • the electrolyte also includes a fluorinated solvent, and the fluorinated solvent is selected from one or more of fluorocarbonate, fluorobenzene, and fluoroether; optionally, the Said fluorocarbonate is selected from At least one of, and/or, the fluorobenzene is And/or, the fluoroether is Wherein, R 2 , R 3 , R 4 , R 5 are each independently selected from C 1 -C 6 alkyl, C 1 -C 6 fluoroalkyl, R 6 , R 7 are each independently selected from C 1 -C 4 alkylene, C 1 -C 4 fluoroalkylene, R 8 , R 9 , R 10 , R 11 , R 12 , R 13 are each independently selected from F or H.
  • the fluorinated solvent is selected from one or more of fluorocarbonate, fluorobenzene, and fluoroether
  • the Said fluorocarbonate is selected from At least one of, and/or,
  • the inventors of the present application have found that after increasing the working voltage of the positive electrode material, the conventional electrolyte solvent is not resistant to oxidation.
  • the fluorinated solvent in the electrolyte By adding the fluorinated solvent in the electrolyte, the oxidation potential of the electrolyte can be further improved, the electrochemical window of the electrolyte can be widened, and the electrolyte can be inhibited.
  • the electrolyte is oxidized and decomposed to reduce the damage of the SEI and CEI films, reduce the expansion of the pole piece during the cycle, and reduce the cycle expansion stress.
  • the fluorocarbonate is selected from at least one of; and/or, the fluorobenzene is And/or, the fluoroether is selected from at least one of the
  • the fluorinated solvent accounts for 10-70% of the mass of the electrolyte.
  • the conductivity of the electrolyte will be greatly affected, thereby affecting the power performance of the cell; when the content is too low, the effect of inhibiting cycle expansion is not good.
  • the electrolyte contains at least one lithium salt selected from the group consisting of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonimide, bistrifluoromethanesulfonate Lithium imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium difluorooxalate borate, lithium difluorodifluorooxalate phosphate, and lithium tetrafluorooxalate phosphate.
  • the lithium salt accounts for 10-14% of the mass of the electrolyte.
  • the electrolyte contains at least one organic solvent selected from the group consisting of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, carbonic acid Methyl propyl ester, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate , methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone.
  • organic solvent selected from the group consisting of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropy
  • the electrolyte also optionally includes additives.
  • additives can include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain performances of batteries, such as additives that improve battery overcharge performance, additives that improve high-temperature or low-temperature performance of batteries, and the like.
  • the positive electrode sheet includes a positive electrode current collector and a positive electrode film layer arranged on at least one surface of the positive electrode current collector, and the positive electrode film layer contains vinylidene fluoride-alkyl unit-acrylate-acrylic acid copolymer as a binder (PVdF-Ac).
  • the binder can further inhibit the cyclic expansion of the positive pole piece and reduce cyclic stress. This is because a small amount of COOH and ester bonds contained in the binder can have strong van der Waals force and hydrogen bond interaction with the corresponding CEI film components, so that the force between the surface of the positive electrode material and the binder is stronger, and the energy Further inhibit the expansion of the positive pole piece and reduce the cyclic stress of the cell.
  • the molecular chain of the binder has low regularity, low crystallinity, and contains copolymerized alkyl chain units, its material is soft, flexible, and stretchable. Since the elongation is high, cyclic expansion can be further suppressed.
  • the binder has a structure of general formula (I):
  • R 1 ', R 2 ', R 3 ', R 4 ' are each independently selected from hydrogen, optionally substituted C 1 -C 8 alkyl, wherein the substituent is selected from at least one of F, Cl, Br,
  • R 5 ', R 6 ', R 7 ' are each independently selected from hydrogen, optionally substituted C 1 -C 6 alkyl, wherein the substituent is selected from at least one of F, Cl, Br,
  • R 8 ' is selected from optionally substituted C 1 -C 15 alkyl, wherein the substituent is selected from at least one of F, Cl, Br,
  • R 9 ′, R 10 ′, and R 11 ′ are each independently selected from hydrogen, optionally substituted C 1 -C 6 alkyl, wherein the substituent is selected from at least one of F, Cl, and Br.
  • the positive electrode current collector can be a metal foil or a composite current collector.
  • aluminum foil can be used as the metal foil.
  • the composite current collector may include a polymer material base and a metal layer formed on at least one surface of the polymer material base.
  • the composite current collector can be formed by forming metal materials (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as polypropylene (PP), polyethylene terephthalic acid It is formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PET polyethylene glycol ester
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the positive electrode active material may be a positive electrode active material known in the art for batteries.
  • the positive active material may include at least one of the following materials: olivine-structured lithium-containing phosphate, lithium transition metal oxide, and their respective modified compounds.
  • the present application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials of batteries can also be used. These positive electrode active materials may be used alone or in combination of two or more.
  • 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 (also abbreviated as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O 2 (also abbreviated as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O 2 (also abbreviated as 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 LiNi
  • the olivine structure contains Examples of lithium phosphates may include, but are not limited to, lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO 4 ), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, lithium manganese iron phosphate and carbon composites at least one of the materials.
  • lithium phosphates may include, but are not limited to, lithium iron phosphate and carbon composites, lithium manganese phosphate (such as LiMnPO 4 ), lithium manganese phosphate and carbon composites, lithium manganese iron phosphate, lithium manganese iron phosphate and carbon composites at least one of the materials.
  • the positive electrode film layer may also optionally include 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 in the following manner: the above-mentioned components used to prepare the positive electrode sheet, such as positive electrode active material, conductive agent, binder and any other components, are dispersed 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 sheet 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 arranged on at least one surface of the negative electrode current collector.
  • the negative film layer contains compounds with epoxy groups or isocyanate groups; when the negative film layer contains compounds with epoxy groups, the compound with epoxy groups contains at least two epoxy groups group, when the negative electrode film layer contains a compound with isocyanate groups, the compound with isocyanate groups contains at least two isocyanate groups.
  • These negative electrode additives can chemically react with groups such as COOH and OH on the surface of the stabilizer in the negative electrode slurry and the binder, so that the stabilizer and the binder in the negative electrode slurry can pass through epoxy groups or isocyanate groups.
  • the compound of the group is connected, so that the surface of the negative electrode active material is more completely covered by the binder, which further restrains the volume expansion of the negative electrode active material after lithium intercalation, and reduces the cyclic expansion stress of the battery cell.
  • the compound having an epoxy group is selected from bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, pentaerythritol glycidyl ether , 1,4-butanediol glycidyl ether, propylene glycol glycidyl ether, glycidyl phthalate, diglycidyl tetrahydrophthalate, diglycidyl hexahydrophthalate, 4,4' -Diaminodiphenylmethane tetraglycidyl epoxy, triglycidyl p-aminophenol, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, tetraglycidyl-1,3- Bis(aminomethylcyclohexane), 9,9-bis[(2,3-epoxypropoxy)phenyl]fluorene, 1,
  • the compound with isocyanate group is selected from toluene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, dimethyl biphenyl diisocyanate, hexamethylene diisocyanate, 2,2,4 -Trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, hydrogenated xylylene diisocyanate, isofor Alone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, methylcyclohexane diisocyanate, 1,4-benzenediisocyanate, norbornane diisocyanate one or more.
  • the negative electrode current collector can use a metal foil or a composite current collector.
  • copper foil can be used as the metal foil.
  • the composite current collector may include a base layer of polymer material and a metal layer formed on at least one surface of the base material of polymer material.
  • Composite current collectors can be formed by metal materials (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.) on polymer material substrates (such as polypropylene (PP), polyethylene terephthalic acid It is formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • the negative electrode active material can be a negative electrode active material known in the art for batteries.
  • the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based material, tin-based material, lithium titanate, and the like.
  • the silicon-based material may be selected from at least one of elemental silicon, silicon-oxygen compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys.
  • the tin-based material may be selected from at least one of simple tin, tin oxide compounds and tin alloys.
  • the present application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials of batteries can also be used. These negative electrode active materials may be used alone or in combination of two or more.
  • the negative electrode film layer may further optionally include a binder.
  • the binder can be selected from styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (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 may also optionally include a conductive agent.
  • the conductive agent can be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
  • the negative electrode film layer may optionally include other additives, such as thickeners (such as sodium carboxymethylcellulose (CMC-Na)) and the like.
  • thickeners such as sodium carboxymethylcellulose (CMC-Na)
  • CMC-Na sodium carboxymethylcellulose
  • the negative electrode sheet can be prepared in the following manner: the above-mentioned components used to prepare the negative electrode sheet, such as negative electrode active material, conductive agent, binder and any other components, are dispersed in a solvent (such as deionized water) to form a negative electrode slurry; the negative electrode slurry is coated on the negative electrode current collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained.
  • a solvent such as deionized water
  • the present application has no particular limitation on the type of the isolation membrane, and any known porous structure isolation membrane with good chemical stability and mechanical stability can be selected.
  • the material of the isolation film can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.
  • the separator can be a single-layer film or a multi-layer composite film, without any particular limitation. When the separator is a multilayer composite film, the materials of each layer may be the same or different, and there is no particular limitation.
  • the positive pole piece, the negative pole piece and the separator can be made into an electrode assembly through a winding process or a lamination process.
  • a second aspect of the present application provides a secondary battery including the electrolyte solution according to the first aspect of the present application.
  • a secondary battery typically includes a positive pole piece, a negative pole piece, an electrolyte, and a separator.
  • active ions are intercalated and extracted back and forth between the positive electrode and the negative electrode.
  • the electrolyte plays the role of conducting ions between the positive pole piece and the negative pole piece.
  • the separator is arranged between the positive pole piece and the negative pole piece, which mainly plays a role in preventing the short circuit of the positive and negative poles, and at the same time allows ions to pass through.
  • the maximum voltage of the secondary battery satisfies 4.25 ⁇ V ⁇ 4.95.
  • the charge cut-off voltage is as high as 4.95V.
  • the secondary battery may include an outer package.
  • the outer package can be used to package the above-mentioned electrode assembly and electrolyte.
  • the outer packaging of the secondary battery may be a hard case, such as a hard plastic case, aluminum case, steel case, and the like.
  • 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 case may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, polybutylene succinate, and the like.
  • FIG. 1 shows a square-shaped 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 a side plate connected to the bottom plate, and the bottom plate and the side plates enclose to form an accommodating cavity.
  • the housing 51 has an opening communicating with the accommodating cavity, and the cover plate 53 can cover the opening to close the accommodating cavity.
  • the positive pole piece, the negative pole piece and the separator can be formed into an electrode assembly 52 through a winding process or a lamination process.
  • the electrode assembly 52 is packaged in the accommodating chamber. Electrolyte is infiltrated in 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.
  • the secondary battery can be assembled into a battery module, and the number of secondary batteries contained in the battery module can be one or more, and the specific number can be selected by those skilled in the art 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 may be fixed by fasteners.
  • the battery module 4 may also include a case having a housing space in which a plurality of secondary batteries 5 are accommodated.
  • the above-mentioned battery modules can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be one or more, and the specific number can be selected by those skilled in the art 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 body 2 and a lower box body 3 , the upper box body 2 can cover the lower box body 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 electric device, which includes at least one of the secondary battery, battery module, or battery pack provided in the present application.
  • the secondary battery, battery module, or battery pack can be used as a power source of the electric device, and can also be used as an energy storage unit of the electric device.
  • the electric devices may include mobile devices (such as mobile phones, notebook computers, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, etc.) , electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but not limited thereto.
  • a secondary battery, a battery module or a battery pack can be selected according to its use requirements.
  • FIG. 6 is an example of an electrical device.
  • the electric device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.
  • a battery pack or a battery module may be used.
  • a device may be a cell phone, tablet, laptop, or the like.
  • the device is generally required to be light and thin, and a secondary battery can be used as a power source.
  • the positive electrode active material LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM622), the conductive agent acetylene black, and the binder polyvinylidene fluoride (PVDF) were dissolved in the solvent N-methylpyrrolidone ( In NMP), the positive electrode slurry is obtained after being fully stirred and mixed uniformly; then the positive electrode slurry is evenly coated on the positive electrode current collector, and then dried, cold pressed, and cut to obtain the positive electrode sheet.
  • SBR binder styrene-butadiene rubber
  • CMC thickener sodium carboxymethyl cellulose
  • a polypropylene film with a thickness of 12 ⁇ m as a separator, stack the positive electrode, separator, and negative electrode in order, so that the separator is between the positive and negative electrodes to play the role of isolation, and the electrode assembly is placed in the battery case In the body, the electrolyte is injected after drying, and then the secondary battery is produced through processes such as formation and standing.
  • the lithium-ion battery At 25°C, charge the lithium-ion battery with a constant current of 0.33C to 4.4V at 0.33C and then charge at a constant voltage of 4.4V until the current is less than 0.05C, then disassemble the battery and measure the corresponding value with a micrometer.
  • the thickness of the anode pole piece is measured 10 times to take the average value.
  • the thickness of the anode pole piece of the lithium-ion battery after capacity is h1
  • the thickness of the anode pole piece of the lithium-ion battery after cycle EOL at 45°C is h2, corresponding to the growth rate of the thickness of the anode pole piece (h2-h1 )/h1.
  • Table 1 The conditional parameter of embodiment and comparative example
  • Example E9 of the present application was prepared according to the same method as Example E2, except that the binder PVDF-Ac was added during the preparation of the positive electrode sheet, wherein PVDF-Ac was prepared by emulsion polymerization, and the The molar ratio of vinylidene fluoride, ethylene, methyl acrylate monomer and acrylic acid monomer is 60:10:25:5.
  • the aggregation method is:
  • the secondary battery has smaller pole piece expansion, smaller cyclic stress.
  • Examples E10-E11 of the present application are prepared according to the same method as in Example E2, except that 1,3-bis(N,N-diglycidylaminomethyl) is added as a negative electrode additive during the preparation of the negative electrode sheet Base) cyclohexane or diphenylmethane diisocyanate, the active material artificial graphite, conductive agent acetylene black, binder styrene-butadiene rubber (SBR), thickener sodium carboxymethylcellulose (CMC) and negative electrode additives according to The mass ratio is 95:2:2:0.8:0.2, which is dissolved in deionized water as a solvent and uniformly mixed with deionized water as a solvent to prepare a negative electrode slurry, as shown in Table 3.
  • SBR binder styrene-butadiene rubber
  • CMC thickener sodium carboxymethylcellulose
  • Comparative Example C6 of the present application was prepared according to the same method as Comparative Example C1, except that, in the test of the secondary battery of Comparative Example C6, the charging cut-off voltage was 4.2V.
  • Example E12 of the present application was prepared according to the same method as Example E2, except that, in the test of the secondary battery of Example E12, the charging cut-off voltage was 4.2V.
  • the present application is not limited to the above-mentioned embodiments.
  • the above-mentioned embodiments are merely examples, and within the scope of the technical solutions of the present application, embodiments that have substantially the same configuration as the technical idea and exert the same effects are included in the technical scope of the present application.
  • various modifications conceivable by those skilled in the art are added to the embodiments, and other forms constructed by combining some components in the embodiments are also included in the scope of the present application. .

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Abstract

本申请提供了一种电解液，所述电解液包含含有S＝O或P＝O的含氟金属盐；和具有结构式Ti-(O-R 1) 4的钛酸酯，其中所述R 1为选自C 1-C 6烷基、C 1-C 6卤代烷基、C 2-C 6烯基、C 2-C 6炔基或C 1-C 6硅烷基中的一种或者多种，以及包含所述电解液的二次电池、电池模块、电池包和用电装置。

Description

电解液、二次电池、电池模块、电池包和用电装置 技术领域
本申请涉及锂电池技术领域，尤其涉及一种电解液、包含其的二次电池、电池模块、电池包和用电装置。
背景技术
近年来，随着锂离子电池的应用范围越来越广泛，锂离子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。由于锂离子电池取得了极大的发展，因此对其能量密度、循环性能和安全性能等也提出了更高的要求。
但是，在高电压充放电过程中，锂离子电池的安全性和性能稳定性一直无法得到有效改善。
发明内容
本申请是鉴于上述课题而进行的，其目的在于，提供一种电解液，使得解决高电压体系循环膨胀而带来的循环应力较大的问题。
为了达到上述目的，本申请提供了一种电解液、包含其的二次电池、电池模块、电池包和用电装置。
本申请的第一方面提供了一种电解液，所述电解液包含
含有S＝O或P＝O的含氟金属盐；和
具有结构式Ti-(O-R 1) 4的钛酸酯，其中所述R 1为选自C 1-C 6烷基、C 1-C 6卤代烷基、C 2-C 6烯基、C 2-C 6炔基或C 1-C 6硅烷基中的一种或者多种。
应用本申请的电解液的电池在高电压体系循环膨胀下具有低的循环应力和低的极片膨胀。
在任意实施方式中，可选地，所述含氟金属盐为选自MSO 3F、MPO 2F 2中的一种或多种；M为金属离子，可选为Li、Na、K或Cs中的一种。
在任意实施方式中，可选地，所述含氟金属盐为选自LiSO 3F、LiPO 2F 2 中的一种或多种。
在任意实施方式中，可选地，所述钛酸酯为选自以下的一种或多种：
Figure PCTCN2021120318-appb-000001
在任意实施方式中，可选地，所述钛酸酯与所述含氟金属盐的摩尔比为2/1～1/20，可选1/8～1/10。当钛酸酯与含氟金属盐的摩尔比在上述范围内时，应用本申请电解液的电池的极片膨胀力更小，循环应力更小。
在任意实施方式中，可选地，所述含氟金属盐占电解液质量的0.01％～8％，可选为0.1％～5％，进一步可选为0.2％～3％；所述钛酸酯占电解液质量的0.01％～8％，可选为0.1％～5％，进一步可选为0.15％～2.5％。
在任意实施方式中，可选地，所述含氟金属盐和所述钛酸酯的总和占电解液质量的0.01～10％，可选为0.1％～8％，进一步可选为0.2％～4％。
在任意实施方式中，可选地，所述电解液还包含氟代溶剂，所述氟代溶剂选自氟代碳酸酯、氟苯、氟醚中的一种或者多种；可选地，所述氟代碳酸酯为选自
Figure PCTCN2021120318-appb-000002
中的至少一种，和/或，所述氟苯为
Figure PCTCN2021120318-appb-000003
和/或，所述氟醚为
Figure PCTCN2021120318-appb-000004
其中，R 2、R 3、R 4、R 5各自独立地选自C 1-C 6烷基、C 1-C 6氟代烷基，R 6、R 7各自独立地选自C 1-C 4亚烷基、C 1-C 4氟代亚烷基，R 8、R 9、R 10、R 11、R 12、R 13各自独立地选自F或H。通过在电解液中添加所述氟代溶剂，可以进一步提高电解液的氧化电位，拓宽电解液电化学窗口，抑制电解液氧化分解，减少SEI和CEI膜的破坏，减少循环过程中极片膨胀，降低循环膨胀应力。
在任意实施方式中，可选地，所述氟代碳酸酯为选自
Figure PCTCN2021120318-appb-000005
Figure PCTCN2021120318-appb-000006
中的至少一种；和/或，所述氟苯为
Figure PCTCN2021120318-appb-000007
和/或，所述氟醚为选自
Figure PCTCN2021120318-appb-000008
Figure PCTCN2021120318-appb-000009
中的至少一种。
在任意实施方式中，可选地，所述氟代溶剂占电解液质量的10～70％。
本申请的第二方面还提供一种二次电池，包括根据本申请第一方面的电解液。
在任意实施方式中，可选地，所述二次电池包括正极极片和负极极片，所述正极极片包括正极集流体与设置在所述正极集流体的至少一个表面的正极膜层，所述正极膜层含有作为粘结剂的偏二氟乙烯-烷基单元-丙烯酸酯-丙烯酸共聚物(PVdF-Ac)。
在任意实施方式中，可选地，所述粘结剂具有通式(I)的结构：
Figure PCTCN2021120318-appb-000010
其中m＝60～75％，
n＝5％～10％，
x＝10％～25％，
y＝3～5％，
R 1’、R 2’、R 3’、R 4’各自独立地选自氢、任选取代的C 1-C 8烷基，其中取代基选自F、Cl、Br中的至少一种，
R 5’、R 6’、R 7’各自独立地选自氢、任选取代的C 1-C 6烷基，其中取代基选自F、Cl、Br中的至少一种，
R 8’选自任选取代的C 1-C 15烷基，其中取代基选自F、Cl、Br中的至少一种，
R 9’、R 10’、R 11’各自独立地选自氢、任选取代的C 1-C 6烷基，其中取代基选自F、Cl、Br中的至少一种。
在任意实施方式中，可选地，所述正极膜层含有至少一种选自以下的正极活性材料：磷酸锰铁锂、锂钴氧化物、锂镍氧化物、锂锰氧化物、锂镍钴锰氧化物、锂镍钴铝氧化物以及上述化合物与其他过渡金属或非过渡金属的复合物。
在任意实施方式中，可选地，所述负极极片包括负极集流体与设置在所 述负极集流体的至少一个表面的负极膜层，所述负极膜层含有具有环氧基团或异氰酸酯基团的化合物；当所述负极膜层含有具有环氧基团的化合物时，所述具有环氧基团的化合物含有至少两个环氧基团，当负极膜层含有异氰酸酯基团的化合物时，所述具有异氰酸酯基团的化合物含有至少两个异氰酸酯基团。
在任意实施方式中，可选地，所述具有环氧基团的化合物为选自双酚A二缩水甘油醚、双酚F二缩水甘油醚、双酚S二缩水甘油醚、季戊四醇缩水甘油醚、1,4-丁二醇缩水甘油醚、丙二醇缩水甘油醚、苯二甲酸缩水甘油酯、四氢邻苯二甲酸二缩水甘油酯、六氢邻苯二甲酸二缩水甘油酯、4,4’-二氨基二苯甲烷四缩水甘油基环氧、三缩水甘油基对氨基苯酚、1,3-双(N,N-二缩水甘油氨甲基)环己烷、四缩水甘油-1,3-双(氨甲基环己烷)、9,9-二[(2,3-环氧丙氧基)苯基]芴、1,4-环己烷二甲醇二缩水甘油醚、四缩水甘油基-4,4’-二氨基二苯醚、四缩水甘油基-3,4’-二氨基二苯醚中的一种或多种；
所述具有异氰酸酯基团的化合物为选自甲苯二异氰酸酯、二苯基甲烷二异氰酸酯、1,5-萘二异氰酸酯、二甲基联苯二异氰酸酯、六亚甲基二异氰酸酯、2,2,4-三甲基己二异氰酸酯、2,4,4-三甲基己二异氰酸酯、苯二甲基二异氰酸酯、四甲基苯二亚甲基二异氰酸酯、氢化苯二亚甲基二异氰酸酯、异佛尔酮二异氰酸酯、4,4’-二环己基甲烷二异氰酸酯、1,4-环己烷二异氰酸酯、甲基环己烷二异氰酸酯、1,4-苯二异氰酸酯、降冰片烷二异氰酸酯中的一种或多种。
本申请的第三方面提供一种电池模块，包括本申请的第二方面的二次电池。
本申请的第四方面提供一种电池包，包括本申请的第二方面的二次电池或本申请的第三方面的电池模块。
本申请的第五方面提供一种用电装置，包括选自本申请的第二方面的二次电池、本申请的第三方面的电池模块或本申请的第四方面的电池包中的至少一种。
本申请的电池模块、电池包或用电装置包括本申请第二方面的二次电池，因此至少具有与本申请第二方面所述的二次电池相同的优势。
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顶盖组件
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电解液、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。
本申请中使用的术语“以上”、“以下”包含本数，例如“一种以上”是指一种或多种，“A和B中的一种以上”是指“A”、“B”或“A和B”。
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)。
除非另有说明，否则本发明上下文中的含量和百分比均基于质量计。
出于本发明的目的，除非另外说明，取代基具有以下含义：
术语“卤素”、“卤素原子”或“卤代”应理解为意指氟、氯、溴和碘，特别是溴、氯或氟，优选氯或氟，更优选氟。
术语“烷基”应理解为意指具有具体指定的碳原子数(例如C 1-C 8，一个、两个、三个、四个、五个、六个、七个或八个碳原子)的直链或支链烃基，例如甲基、乙基、正丙基、异丙基、正丁基、异丁基、仲丁基、叔丁基、戊基、异戊基、己基、庚基、辛基、2-甲基丁基、1-甲基丁基、1-乙基丙基、1,2-二甲基丙基、新戊基、1,1-二甲基丙基、4-甲基戊基、3-甲基戊基、2-甲基戊基、1-甲基戊基、2-乙基丁基、1-乙基丁基、3,3-二甲基丁基、2,2-二甲基丁基、 1,1-二甲基丁基、2,3-二甲基丁基、1,3-二甲基丁基或1,2-二甲基丁基。术语“C 1-C 6-烷基”应理解为意指具有1、2、3、4、5或6个碳原子的直链或支链烃基，例如甲基、乙基、正丙基、异丙基、正丁基、叔丁基、戊基、异戊基、己基、2-甲基丁基、1-甲基丁基、1-乙基丙基、1,2-二甲基丙基、新戊基、1,1-二甲基丙基、4-甲基戊基、3-甲基戊基、2-甲基戊基、1-甲基戊基、2-乙基丁基、1-乙基丁基、3,3-二甲基丁基、2,2-二甲基丁基、1,1-二甲基丁基、2,3-二甲基丁基、1,3-二甲基丁基或1,2-二甲基丁基。优选地，所述烷基具有1、2、3或4个碳原子(“C 1-C 4-烷基”)，例如甲基、乙基、正丙基或异丙基。
术语“C 2-C 6-烯基”应理解为意指直链或支链的单价烃基，其含有一个双键，并具有2、3、4、5或6个碳原子。特别地，所述烯基为C 2-C 3-烯基、C 3-C 6-烯基或C 3-C 4-烯基。所述烯基为例如乙烯基、烯丙基、(E)-2-甲基乙烯基、(Z)-2-甲基乙烯基或异丙烯基。
术语“C 2-C 6-炔基”应理解为意指直链或支链的单价烃基，其含有一个三键，并包含2、3、4、5或6个碳原子。特别地，所述炔基为C 2-C 3-炔基、C 3-C 6-炔基或C 3-C 4-炔基。所述C 2-C 3-炔基为，例如乙炔基、丙-1-炔基或丙-2-炔基。
术语“C 1-C 4-亚烷基”应理解为意指具有1至4个碳原子，特别是2、3或4个碳原子(例如在“C 2-C 4-亚烷基”中)的直链、二价并且饱和的烃基，例如亚乙基、亚正丙基、亚正丁基、亚正戊基或亚正己基，优选亚正丙基或亚正丁基。
术语“C 1-C 6-硅烷基”应理解为意指直链或支链的Si-烷基，其包含1、2、3、4、5或6个碳原子，例如(但不限于此)三甲基甲硅烷基、三乙基甲硅烷基。
“卤代烷基”、“卤代烯基”、“卤代炔基”和“卤代亚烷基”分别表示被相同或不同的卤原子部分或完全取代的烷基、烯基、炔基和亚烷基，例如单卤代烷基，例如CH 2CH 2Cl、CH 2CH 2Br、CHClCH 3、CH 2Cl、CH 2F；全卤代烷基，例如CCl 3、CClF 2、CFCl 2、CF 2CClF 2、CF 2CClFCF 3；卤代烷基，例如CH 2CHFCl、CF 2CClFH、CF 2CBrFH、CH 2CF 3；术语全卤代烷基还包括术语全氟烷基。
在本发明中，“C 1-C 8”应解释为包括其中的任何子范围，例如C 1-C 8、C 1-C 7、 C 1-C 6、C 1-C 5、C 1-C 4、C 1-C 3、C 1-C 2、C 2-C 8、C 2-C 7、C 2-C 6、C 2-C 5、C 2-C 4、C 2-C 3、C 3-C 8、C 3-C 7、C 3-C 6、C 3-C 5、C 3-C 4、C 4-C 8、C 4-C 7、C 4-C 6、C 4-C 5、C 5-C 8、C 5-C 7、C 5-C 6、C 6-C 8、C 6-C 7、C 7-C 8。
类似地，术语“C 1-C 6”应解释为包括其中的任何子范围，例如C 1-C 6、C 1-C 5、C 1-C 4、C 1-C 3、C 1-C 2、C 2-C 6、C 2-C 5、C 2-C 4、C 2-C 3、C 3-C 6、C 3-C 5、C 3-C 4、C 4-C 6、C 4-C 5、C 5-C 6。
类似地，术语“C 1-C 4”应解释为包括其中的任何子范围，例如C 1-C 4、C 1-C 3、C 1-C 2、C 2-C 4、C 2-C 3、C 3-C 4。
类似地，术语“C 2-C 6”应解释为包括其中的任何子范围，例如C 2-C 5、C 2-C 4、C 2-C 3、C 3-C 4、C 3-C 5、C 3-C 6、C 4-C 5、C 4-C 6、C 5-C 6。
为了提高电池的能量密度，提高正极材料的工作电位成为了研究者们的首要策略。如常规三元正极材料的工作电压提高至4.4V以上，具有更高电压和克容量的正极材料如富锂层状正极、尖晶石氧化物LiNi 0.5Mn 1.5O 4等，工作电压较高，电压上限已接近5V。本申请发明人发现，提高电压后，电解液不耐氧化，导致整个电池性能下降，此外提高正极材料工作电压后，导致正极材料脱锂量较大，对应正极材料和负极材料体积变化较大，进而导致在电芯充放电过程中电芯总的体积变化较大，电芯内部游离电解液被挤出，如果电解液不能及时回流到电芯内部，会导致电芯在循环过程中由于动力学不足而导致析锂发生，此外电芯循环膨胀较大，还会导致电芯极片出现褶皱，更严重时还会导致电芯短路，引发安全问题，极大的影响的电芯的可靠性。
经过大量实验，本申请发明人发现当所述高电压体系电解液中含有如下添加剂时，能显著抑制电芯的循环膨胀，显著降低循环膨胀应力：
含有S＝O或P＝O的含氟金属盐；和
具有结构式Ti-(O-R 1) 4的钛酸酯，其中所述R 1为选自C 1-C 6烷基、C 1-C 6卤代烷基、C 2-C 6烯基、C 2-C 6炔基或C 1-C 6硅烷基中的一种或者多种。
[电解液]
本申请的第一方面提供一种电解液，所述电解液包含
含有S＝O或P＝O的含氟金属盐；和
具有结构式Ti-(O-R 1) 4的钛酸酯，其中所述R 1为选自C 1-C 6烷基、C 1-C 6卤代烷基、C 2-C 6烯基、C 2-C 6炔基或C 1-C 6硅烷基中的一种或者多种。
发明人意外地发现：通过在电解液中添加上述添加剂，应用本申请的电解液的电池具有低的循环应力。在电芯充放电过程中，本申请的电解液能在正负极形成多维网状且具有韧性的聚合物和无机物复合SEI膜，显著降低循环应力。
在一些实施方式中，可选地，所述含氟金属盐为选自MSO 3F、MPO 2F 2中的一种或多种；M为金属离子，可选为Li、Na、K或Cs中的一种。
在一些实施方式中，可选地，所述含氟金属盐为选自LiSO 3F、LiPO 2F 2中的一种或多种。
在任意实施方式中，可选地，所述钛酸酯为选自以下的一种或多种：
Figure PCTCN2021120318-appb-000011
在一些实施方式中，可选地，所述钛酸酯与所述含氟金属盐的摩尔比为2/1～1/20，可选1/8～1/10。当钛酸酯与含氟金属盐的摩尔比在上述范围内时，应用本申请电解液的电池的极片膨胀更小，循环应力更小。通过调控钛酸酯与含氟金属盐摩尔比，使得对应SEI膜对正负极活性物质具有较好的束缚力且具有较好的韧性。当所述摩尔比过高时，导致SEI膜柔韧性变差，抑制循环膨胀的效果不佳。当所述摩尔比过低时，SEI膜容易脆裂，进而导致极片膨胀，电芯循环应力较大。
在一些实施方式中，可选地，所述含氟金属盐占电解液质量的0.01％～8％，可选为0.1％～5％，进一步可选为0.2％～3％；所述钛酸酯占电解液质量的0.01％～8％，可选为0.1％～5％，进一步可选为0.15％～2.5％。
在一些实施方式中，可选地，所述含氟金属盐和所述钛酸酯的总和占电解液质量的0.01～10％，可选为0.1％～8％，进一步可选为0.2％～4％。
在一些实施方式中，可选地，所述电解液还包含氟代溶剂，所述氟代溶剂选自氟代碳酸酯、氟苯、氟醚中的一种或者多种；可选地，所述氟代碳酸 酯为选自
Figure PCTCN2021120318-appb-000012
中的至少一种，和/或，所述氟苯为
Figure PCTCN2021120318-appb-000013
和/或，所述氟醚为
Figure PCTCN2021120318-appb-000014
其中，R 2、R 3、R 4、R 5各自独立地选自C 1-C 6烷基、C 1-C 6氟代烷基，R 6、R 7各自独立地选自C 1-C 4亚烷基、C 1-C 4氟代亚烷基，R 8、R 9、R 10、R 11、R 12、R 13各自独立地选自F或H。本申请发明人发现，提高正极材料工作电压后，常规电解液溶剂不耐氧化，通过在电解液中添加所述氟代溶剂，可以进一步提高电解液的氧化电位，拓宽电解液电化学窗口，抑制电解液氧化分解，减少SEI和CEI膜的破坏，减少循环过程中极片膨胀，降低循环膨胀应力。
在一些实施方式中，可选地，所述氟代碳酸酯为选自
Figure PCTCN2021120318-appb-000015
Figure PCTCN2021120318-appb-000016
中的至少一种；和/或，所述氟苯为
Figure PCTCN2021120318-appb-000017
和/或，所述氟醚为选自
Figure PCTCN2021120318-appb-000018
Figure PCTCN2021120318-appb-000019
中的至少一种。
在一些实施方式中，可选地，所述氟代溶剂占电解液质量的10～70％。当所述含量太高时，会极大影响电解液的电导率，进而影响电芯功率性能；当所述含量太低时，抑制循环膨胀效果不佳。
在一些实施方式中，电解液含有至少一种选自如下的锂盐：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。可选地，所述锂盐占电解液质量的10～14％。
在一些实施方式中，电解液含有至少一种选自如下的有机溶剂：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，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。
[正极极片]
正极极片包括正极集流体与设置在所述正极集流体的至少一个表面的正极膜层，所述正极膜层含有作为粘结剂的偏二氟乙烯-烷基单元-丙烯酸酯-丙烯酸共聚物(PVdF-Ac)。所述粘合剂能进一步抑制正极极片循环膨胀，减少循环应力。这是由于该粘结剂中含有的少量COOH和酯键，能与对应CEI膜组分具有较强的范德华力和氢键作用，使得正极材料表面和粘结剂之间作用力较强，能进一步抑制正极极片膨胀，减少电芯循环应力，此外由于该粘结剂分子链的规整度低，结晶度小，且含有共聚的烷基链单元，因此其材质较软、柔韧性好、拉伸强度大，因此，能进一步抑制循环膨胀。
在一些实施方式中，可选地，所述粘结剂具有通式(I)的结构：
Figure PCTCN2021120318-appb-000020
其中m＝60～75％，
n＝5％～10％，
x＝10％～25％，
y＝3～5％，
R 1’、R 2’、R 3’、R 4’各自独立地选自氢、任选取代的C 1-C 8烷基，其中取代基选自F、Cl、Br中的至少一种，
R 5’、R 6’、R 7’各自独立地选自氢、任选取代的C 1-C 6烷基，其中取代基选自F、Cl、Br中的至少一种，
R 8’选自任选取代的C 1-C 15烷基，其中取代基选自F、Cl、Br中的至少一种，
R 9’、R 10’、R 11’各自独立地选自氢、任选取代的C 1-C 6烷基，其中取代基选自F、Cl、Br中的至少一种。
在上述通式(I)中，m、n、x、y代表每种单体在该聚合物中的占比；可选地，m+n+x+y＝100％。
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与设置在所述负极集流体的至少一个表面的负极膜层。所述负极膜层含有具有环氧基团或异氰酸酯基团的化合物；当所述负极膜层含有具有环氧基团的化合物时，所述具有环氧基团的化合物含有至少两个环氧基团，当负极膜层含有异氰酸酯基团的化合物时，所述具有异氰酸酯基团的化合物含有至少两个异氰酸酯基团。这些负极添加剂可与负极浆料中的稳定剂、粘结剂表面的COOH和OH等基团发生化学反应，从而使得负极浆料中的稳定剂和粘结剂通过含有环氧基团或者异氰酸酯基团的化合物连接起来，进而使得负极活性材料表面被粘结剂包覆更加完整，进一步束缚了负极活性材料嵌锂后的体积膨胀，降低了电芯循环膨胀应力。
在一些实施方式中，可选地，所述具有环氧基团的化合物为选自双酚A二缩水甘油醚、双酚F二缩水甘油醚、双酚S二缩水甘油醚、季戊四醇缩水甘油醚、1,4-丁二醇缩水甘油醚、丙二醇缩水甘油醚、苯二甲酸缩水甘油酯、四氢邻苯二甲酸二缩水甘油酯、六氢邻苯二甲酸二缩水甘油酯、4,4’-二氨基二苯甲烷四缩水甘油基环氧、三缩水甘油基对氨基苯酚、1,3-双(N,N-二缩水甘油氨甲基)环己烷、四缩水甘油-1,3-双(氨甲基环己烷)、9,9-二[(2,3-环氧丙氧基)苯基]芴、1,4-环己烷二甲醇二缩水甘油醚、四缩水甘油基-4,4’-二氨基二苯醚、四缩水甘油基-3,4’-二氨基二苯醚中的一种或多种；
所述具有异氰酸酯基团的化合物为选自甲苯二异氰酸酯、二苯基甲烷二异氰酸酯、1,5-萘二异氰酸酯、二甲基联苯二异氰酸酯、六亚甲基二异氰酸酯、2,2,4-三甲基己二异氰酸酯、2,4,4-三甲基己二异氰酸酯、苯二甲基二异氰酸酯、四甲基苯二亚甲基二异氰酸酯、氢化苯二亚甲基二异氰酸酯、异佛尔酮二异氰酸酯、4,4’-二环己基甲烷二异氰酸酯、1,4-环己烷二异氰酸酯、甲基环己烷二异氰酸酯、1,4-苯二异氰酸酯、降冰片烷二异氰酸酯中的一种或多种。
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。
[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。
[二次电池]
本申请的第二方面提供一种二次电池，包括根据本申请第一方面的电解液。
通常情况下，二次电池包括正极极片、负极极片、电解液和隔离膜。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。电解液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。
在一些实施方式中，可选地，所述二次电池的使用最大电压满足4.25≤V≤4.95。对于尖晶石LNMO体系，其充电截止电压最高达4.95V。
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液。
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。
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
【正极极片的制备】
将正极活性材料LiNi 0.6Co 0.2Mn 0.2O 2(NCM622)、导电剂乙炔黑、粘结剂聚偏二氟乙烯(PVDF)按质量比为96.5:1.5:2溶于溶剂N-甲基吡咯烷酮(NMP)中，充分搅拌混合均匀后得到正极浆料；之后将正极浆料均匀涂覆于正极集流体上，之后经过烘干、冷压、分切，得到正极极片。
【负极极片的制备】
将活性物质人造石墨、导电剂乙炔黑、粘结剂丁苯橡胶(SBR)、增稠剂羧甲基纤维素钠(CMC)按照质量比为95:2:2:1溶于溶剂去离子水中，与溶剂去离子水均匀混合后制备成负极浆料；然后将负极浆料均匀涂覆在负极集流体铜箔上，烘干后得到负极膜片，再经过冷压、分切得到负极极片。
【电解液的制备】
在氩气气氛手套箱中(H 2O<0.1ppm，O 2<0.1ppm)，参照表1，有机溶剂按照质量比混合均匀，加入表中所示的盐和添加剂，搅拌均匀，得到相应的电解液。
【二次电池的制备】
以厚度12μm的聚丙烯膜作为隔离膜，将正极极片、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，将电极组件置于电池壳体中，干燥后注入电解液，再经过化成、静置等工艺制得二次电池。
其他实施例和对比例的条件参数如表1中所示，这些实施例和对比例的【正极极片的制备】、【负极极片的制备】、【电解液的制备】和【电池的制备】均与实施例1的工艺相同。
【相关参数测试】
1、锂离子电池的45℃循环
将电芯放置在三片钢板夹具中，然后连接上压力传感器，检测循环过程中电芯的膨胀力，在45℃下，将锂离子电池以1C恒流充电至4.4V，然后以4.4V恒压充电至电流小于0.05C，然后将锂离子电池以1C恒流放电至2.8V，此为一个充放电过程。如此反复进行充电和放电，进行500cls，记录第500cls下充电过程中电芯的最大膨胀力。
2、极片厚度测试
在25℃下，分别将容量后和45℃循环500cls后锂离子电池以0.33C恒流充电至4.4V，然后以4.4V恒压充电至电流小于0.05C，然后拆解电池，用千分尺测量对应阳极极片厚度，测量10次取平均值，容量后锂离子电池阳极极片厚度为h1，45℃循环EOL后锂离子电池阳极极片厚度为h2，对应阳极极片厚度增长率(h2-h1)/h1。
表1：实施例与对比例的条件参数
Figure PCTCN2021120318-appb-000021
Figure PCTCN2021120318-appb-000022
综合分析表1中实施例E1-E6以及对比例C1-C3可知，实施例E1-E6对应的二次电池的极片膨胀、循环应力显著低于对比例C1-C3。
通过比较对比例C4-C5和实施例E1-E5可以看出，当钛酸酯与含氟金属盐的摩尔比为2/1～1/20时，二次电池的极片膨胀和循环应力更优。
通过实施例E7-E8可以看出，当电解液含有氟代溶剂时，二次电池的极片膨胀和循环应力进一步得到优化。
【正极膜层的粘结剂对电池性能的影响】
本申请实施例E9按照与实施例E2相同的方法制备，不同之处在于，在正极极片的制备过程中加入粘结剂PVDF-Ac，其中PVDF-Ac通过乳液聚合方法制备，合成中采用的偏二氟乙烯、乙烯、丙烯酸甲酯单体、丙烯酸单体的 摩尔比为60：10：25：5。
聚合方法为：
在不锈钢反应釜中加入去离子水、分散剂、pH调节剂、和链转移剂，真空脱氧，加入定量的丙烯酸酯、丙烯酸单体和如上所需的偏二氟乙烯的1/2，加入引发剂，控制温度和压力，开始聚合反应，并不断补加剩余的1/2的偏二氟乙烯及乙烯，待聚合结束后，聚合物经破乳、洗涤、干燥，得到PVdF-Ac产品，其分子量为90万。
表2：粘结剂对电池性能的影响
Figure PCTCN2021120318-appb-000023
根据表2可知，当正极膜层含有作为粘结剂的偏二氟乙烯-烷基单元-丙烯酸酯-丙烯酸共聚物(PVdF-Ac)时，二次电池具有更小的极片膨胀、更小的循环应力。
【负极膜层的添加剂对电池性能的影响】
本申请实施例E10-E11按照与实施例E2相同的方法制备，不同之处在于，在负极极片的制备过程中加入作为负极添加剂的1,3-双(N,N-二缩水甘油氨甲基)环己烷或二苯基甲烷二异氰酸酯，将活性物质人造石墨、导电剂乙炔黑、粘结剂丁苯橡胶(SBR)、增稠剂羧甲基纤维素钠(CMC)和负极添加剂按照质量比为95:2:2:0.8:0.2溶于溶剂去离子水中，与溶剂去离子水均匀混合后制备成负极浆料，如表3所示。
表3：负极膜层的添加剂对电池性能的影响
Figure PCTCN2021120318-appb-000024
根据表3可知，当负极膜层含有1,3-双(N,N-二缩水甘油氨甲基)环己烷或二苯基甲烷二异氰酸酯时，二次电池具有更小的极片膨胀、更小的循环应力。
【不同电压下电池的性能】
本申请对比例C6按照与对比例C1相同的方法制备，不同之处在于，对比例C6的二次电池的测试中，充电截止电压为4.2V。本申请实施例E12按照与实施例E2相同的方法制备，不同之处在于，实施例E12的二次电池的测试中，充电截止电压为4.2V。
表4：在4.2V电压下电池的性能
Figure PCTCN2021120318-appb-000025
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 (19)

  1. 一种电解液，所述电解液包含
    含有S＝O或P＝O的含氟金属盐；和
    具有结构式Ti-(O-R 1) 4的钛酸酯，其中所述R 1为选自C 1-C 6烷基、C 1-C 6卤代烷基、C 2-C 6烯基、C 2-C 6炔基或C 1-C 6硅烷基中的一种或者多种。
  2. 根据权利要求1所述的电解液，其特征在于，所述含氟金属盐为选自MSO 3F、MPO 2F 2中的一种或多种；M为金属离子，可选为Li、Na、K或Cs中的一种。
  3. 根据权利要求1或2所述的电解液，其特征在于，所述含氟金属盐为选自LiSO 3F、LiPO 2F 2中的一种或多种。
  4. 根据权利要求1-3中任一项所述的电解液，其特征在于，所述钛酸酯为选自以下的一种或多种：
    Figure PCTCN2021120318-appb-100001
    Figure PCTCN2021120318-appb-100002
  5. 根据权利要求1-4中任一项所述的电解液，其特征在于，所述钛酸酯与所述含氟金属盐的摩尔比为2/1～1/20，可选1/8～1/10。
  6. 根据权利要求1-5中任一项所述的电解液，其特征在于，所述含氟金属盐占电解液质量的0.01％～8％，可选为0.1％～5％，进一步可选为0.2％～3％；所述钛酸酯占电解液质量的0.01％～8％，可选为0.1％～5％，进一步可选为0.15％～2.5％。
  7. 根据权利要求1-6中任一项所述的电解液，其特征在于，所述含氟金属盐和所述钛酸酯的总和占电解液质量的0.01～10％，可选为0.1％～8％，进一步可选为0.2％～4％。
  8. 根据权利要求1-7中任一项所述的电解液，其特征在于，所述电解液还包含氟代溶剂，所述氟代溶剂选自氟代碳酸酯、氟苯、氟醚中的一种或者多种；可选地，所述氟代碳酸酯为选自
    Figure PCTCN2021120318-appb-100003
    Figure PCTCN2021120318-appb-100004
    中的至少一种，和/或，所述氟苯为
    Figure PCTCN2021120318-appb-100005
    和/或，所述氟醚为
    Figure PCTCN2021120318-appb-100006
    其中，R 2、R 3、R 4、R 5各自独立地选自C 1-C 6烷基、C 1-C 6氟代烷基，R 6、R 7各自独立地选自C 1-C 4亚烷基、C 1-C 4氟代亚烷基，R 8、R 9、R 10、R 11、R 12、R 13各自独立地选自F或H。
  9. 根据权利要求1-8中任一项所述的电解液，其特征在于，所述氟代碳酸酯为选自
    Figure PCTCN2021120318-appb-100007
    Figure PCTCN2021120318-appb-100008
    中的至少一种；和/或，所述氟苯为
    Figure PCTCN2021120318-appb-100009
    和/或，所述氟醚为选自
    Figure PCTCN2021120318-appb-100010
    Figure PCTCN2021120318-appb-100011
    中的至少一种。
  10. 根据权利要求8所述的电解液，其特征在于，所述氟代溶剂占电解液质量的10～70％。
  11. 一种二次电池，其特征在于，
    包括权利要求1～10中任一项所述的电解液。
  12. 根据权利要求11所述的二次电池，其特征在于，
    所述二次电池包括正极极片和负极极片，所述正极极片包括正极集流体与设置在所述正极集流体的至少一个表面的正极膜层，所述正极膜层含有作为粘结剂的偏二氟乙烯-烷基单元-丙烯酸酯-丙烯酸共聚物(PVdF-Ac)。
  13. 根据权利要求12所述的二次电池，其特征在于，
    所述粘结剂具有通式(I)的结构：
    Figure PCTCN2021120318-appb-100012
    其中m＝60～75％，
    n＝5％～10％，
    x＝10％～25％，
    y＝3～5％，
    R 1’、R 2’、R 3’、R 4’各自独立地选自氢、任选取代的C 1-C 8烷基，其中取代基选自F、Cl、Br中的至少一种，
    R 5’、R 6’、R 7’各自独立地选自氢、任选取代的C 1-C 6烷基，其中取代基选自F、Cl、Br中的至少一种，
    R 8’选自任选取代的C 1-C 15烷基，其中取代基选自F、Cl、Br中的至少一种，
    R 9’、R 10’、R 11’各自独立地选自氢、任选取代的C 1-C 6烷基，其中取代基选自F、Cl、Br中的至少一种。
  14. 根据权利要求12所述的二次电池，其特征在于，
    所述正极膜层含有至少一种选自以下的正极活性材料：磷酸锰铁锂、锂钴氧化物、锂镍氧化物、锂锰氧化物、锂镍钴锰氧化物、锂镍钴铝氧化物以及上述化合物与其他过渡金属或非过渡金属的复合物。
  15. 根据权利要求12所述的二次电池，其特征在于，
    所述负极极片包括负极集流体与设置在所述负极集流体的至少一个表面的负极膜层，所述负极膜层含有具有环氧基团或异氰酸酯基团的化合物；当所述负极膜层含有具有环氧基团的化合物时，所述具有环氧基团的化合物含有至少两个环氧基团，当负极膜层含有异氰酸酯基团的化合物时，所述具有异氰酸酯基团的化合物含有至少两个异氰酸酯基团。
  16. 根据权利要求15所述的二次电池，其特征在于，
    所述具有环氧基团的化合物为选自双酚A二缩水甘油醚、双酚F二缩水甘油醚、双酚S二缩水甘油醚、季戊四醇缩水甘油醚、1,4-丁二醇缩水甘油醚、丙二醇缩水甘油醚、苯二甲酸缩水甘油酯、四氢邻苯二甲酸二缩水甘油酯、六氢邻苯二甲酸二缩水甘油酯、4,4’-二氨基二苯甲烷四缩水甘油基环氧、三缩水甘油基对氨基苯酚、1,3-双(N,N-二缩水甘油氨甲基)环己烷、四缩水甘油-1,3-双(氨甲基环己烷)、9,9- 二[(2,3-环氧丙氧基)苯基]芴、1,4-环己烷二甲醇二缩水甘油醚、四缩水甘油基-4,4’-二氨基二苯醚、四缩水甘油基-3,4’-二氨基二苯醚中的一种或多种；
    所述具有异氰酸酯基团的化合物为选自甲苯二异氰酸酯、二苯基甲烷二异氰酸酯、1,5-萘二异氰酸酯、二甲基联苯二异氰酸酯、六亚甲基二异氰酸酯、2,2,4-三甲基己二异氰酸酯、2,4,4-三甲基己二异氰酸酯、苯二甲基二异氰酸酯、四甲基苯二亚甲基二异氰酸酯、氢化苯二亚甲基二异氰酸酯、异佛尔酮二异氰酸酯、4,4’-二环己基甲烷二异氰酸酯、1,4-环己烷二异氰酸酯、甲基环己烷二异氰酸酯、1,4-苯二异氰酸酯、降冰片烷二异氰酸酯中的一种或多种。
  17. 一种电池模块，其特征在于，包括权利要求11-16中任一项所述的二次电池。
  18. 一种电池包，其特征在于，包括权利要求11-16中任一项所述的二次电池或权利要求17所述的电池模块。
  19. 一种用电装置，其特征在于，包括选自权利要求11-16中任一项所述的二次电池、权利要求17所述的电池模块或权利要求18所述的电池包中的至少一种。
PCT/CN2021/120318 2021-09-24 2021-09-24 电解液、二次电池、电池模块、电池包和用电装置 WO2023044753A1 (zh)

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JP2022557174A JP2023547001A (ja) 2021-09-24 2021-09-24 電解液、二次電池、電池モジュール、電池パック及び電力消費装置
KR1020227032148A KR20230044353A (ko) 2021-09-24 2021-09-24 전해액, 이차전지, 배터리 모듈, 배터리 팩과 전기장치
EP21927058.4A EP4184648A4 (en) 2021-09-24 2021-09-24 ELECTROLYTE, SECONDARY BATTERY, BATTERY MODULE, BATTERY PACK AND POWER CONSUMPTION APPARATUS
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