WO2021017759A1 - 一种锂离子电池及其相关的电池模块、电池包和装置 - Google Patents

一种锂离子电池及其相关的电池模块、电池包和装置 Download PDF

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WO2021017759A1
WO2021017759A1 PCT/CN2020/100291 CN2020100291W WO2021017759A1 WO 2021017759 A1 WO2021017759 A1 WO 2021017759A1 CN 2020100291 W CN2020100291 W CN 2020100291W WO 2021017759 A1 WO2021017759 A1 WO 2021017759A1
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lithium
ion battery
lithium salt
electrolyte
lithium ion
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PCT/CN2020/100291
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English (en)
French (fr)
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梁成都
李志强
韩昌隆
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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 EP20848419.6A priority Critical patent/EP3905412B1/en
Publication of WO2021017759A1 publication Critical patent/WO2021017759A1/zh
Priority to US17/583,728 priority patent/US20220149437A1/en

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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
    • H01M10/0568—Liquid materials characterised by the solutes
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B21/00—Nitrogen; Compounds thereof
    • C01B21/082—Compounds containing nitrogen and non-metals and optionally metals
    • C01B21/086—Compounds containing nitrogen and non-metals and optionally metals containing one or more sulfur atoms
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
    • C01D15/00—Lithium compounds
    • C01D15/005—Lithium hexafluorophosphate
    • 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
    • H01M10/0569—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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • 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
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • 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
    • H01M4/362—Composites
    • H01M4/364—Composites as mixtures
    • 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
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/40—Electric properties
    • 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
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • 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
    • H01M2004/027—Negative electrodes
    • 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
    • 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
    • H01M2300/0037—Mixture of solvents
    • 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

  • This application relates to the field of battery technology, and in particular to a lithium ion battery and its related battery modules, battery packs and devices.
  • lithium-ion batteries Since the mass production at the end of the 20th century, lithium-ion batteries have been widely used in the field of consumer electronics due to their high specific energy, no memory effect, and long cycle life. In recent years, the global environmental protection situation has become increasingly severe, and the shortage of fossil fuels has become more and more serious. Therefore, as materials and processes continue to mature, lithium-ion batteries as a clean energy source have gradually become an important source of power for automobiles.
  • Lithium iron phosphate has a stable structure and low activity, and can provide high safety and long cycle life. However, its low platform, low specific energy, and energy density often cannot meet the ever-increasing range of electric vehicles.
  • the nickel cobalt lithium manganate ternary material combines the advantages of lithium nickelate, lithium cobaltate, and lithium manganate. It has obvious advantages in life and energy density, but the ternary material itself is not stable enough and is alkaline.
  • LiFSI lithium bisfluorosulfonimide
  • the purpose of this application is to provide a lithium-ion battery with high voltage resistance to solve the problems in the prior art.
  • a lithium ion battery including a positive pole piece, a negative pole piece, a separator, and an electrolyte.
  • the negative pole piece includes a negative electrode active material layer containing a negative electrode active material.
  • the electrolyte includes an electrolyte lithium salt, the electrolyte lithium salt includes a first lithium salt, the first lithium salt is selected from fluorine-containing sulfonimide lithium salts, the first lithium salt and the negative electrode Satisfy relation (1) (g/cm 3 ):
  • M E is the lithium ion battery in the total mass of the electrolytic solution, the unit is G;
  • C I is the mass percentage of the first lithium salt relative to the electrolyte, and the unit is %;
  • M A is the lithium ion battery in the total mass of the negative electrode active material layer, units of G;
  • PD A is the compacted density of the negative active material layer, in g/cm 3 ;
  • P A is the porosity of the anode active material layer, the unit is%.
  • the application provides a battery module, which includes the lithium ion battery described in the first aspect of the application.
  • the present application provides a battery pack including the battery module described in the second aspect of the present application.
  • the application also provides a device, which includes the lithium ion battery described in the first aspect of the application.
  • This application uses fluorine-containing sulfonimide lithium salt as the electrolyte of the first lithium salt, and controlling the content of the fluorine-containing sulfonimide lithium salt in the unit volume pores of the negative pole piece within a certain range can be effective Suppress the battery's impedance increase too fast or the concentration polarization is too large, can give full play to the advantages of high temperature and high conductivity of the fluorine-containing sulfonimide lithium salt, the formed battery floating charge physical resistance increase rate is low, avoid the cycle In the later stage, safety problems such as lithium evolution will eventually be achieved, which will eventually achieve high safety performance, long cycle life, and excellent high-temperature storage.
  • FIG. 1 is a schematic diagram of an embodiment of the lithium ion battery of the present application.
  • FIG. 2 is an exploded schematic diagram of an embodiment of the lithium ion battery of the present application.
  • Fig. 3 is a schematic diagram of an embodiment of a battery module.
  • Fig. 4 is a schematic diagram of an embodiment of a battery pack.
  • Fig. 5 is an exploded view of Fig. 4.
  • FIG. 6 is a schematic diagram of an embodiment of a device in which the lithium ion battery of the present application is used as a power source.
  • any lower limit may be combined with any upper limit to form an unspecified range; and any lower limit may be combined with other lower limits to form an unspecified range, and any upper limit may be combined with any other upper limit to form an unspecified range.
  • each individually disclosed point or single value can be used as a lower limit or upper limit in combination with any other point or single value or with other lower or upper limits to form an unspecified range.
  • the lithium ion battery of the present application will be described in detail below.
  • the first aspect of the present application provides a lithium ion battery (also referred to as a lithium ion secondary battery), including a positive pole piece, a negative pole piece, a separator, and an electrolyte.
  • the negative pole piece includes a negative electrode active material containing a negative electrode active material.
  • the material layer, the electrolyte includes an electrolyte lithium salt, the electrolyte lithium salt includes a first lithium salt, the first lithium salt is selected from fluorine-containing sulfonimide lithium salt, the first lithium salt and the negative electrode
  • the pole piece satisfies the relationship (1) (g/cm 3 ):
  • a lithium salt with a lower content of F element is used as the main electrolyte of the electrolyte.
  • the F element in the fluorosulfonimide lithium salt Relatively low content, good thermal stability, and less HF content, which can effectively suppress the gas generation problem of the cathode material, and can provide excellent battery safety.
  • the fluorine-containing sulfonimide lithium salt is formulated into an electrolyte In the future, the electrical conductivity is higher than that of the lithium hexafluorophosphate electrolyte, and it shows obvious advantages in terms of cycle and storage life.
  • the concentration of the fluorine-containing sulfonimide lithium salt in the electrolyte is too high, it may cause the viscosity of the electrolyte to increase and the fluidity to deteriorate, which will affect the substance in the lithium ion Widely used in batteries. Therefore, in this application, according to the microstructure characteristics of the negative electrode sheet, the content of the fluorine-containing sulfonimide lithium salt per unit volume of the pores in the negative electrode active material layer is adjusted to be within a certain range, and the protection of the negative electrode active material layer is controlled.
  • Liquid volume control the fluidity of the fluorine-containing sulfonimide lithium salt in the negative electrode active material layer, effectively inhibit the rapid consumption of the high-safety electrolyte, prevent the battery’s impedance from increasing too fast or the concentration polarization, and avoiding circulation In the later stage, safety issues such as lithium analysis occurred.
  • the content of fluorine-containing sulfonyl imide lithium salt per unit volume of pores in the negative active material layer may be 0.6 g/cm 3 ⁇ 6.2 g/cm 3 , 0.6 g/cm 3 ⁇ 1.0g/cm 3 , 1.0g/cm 3 ⁇ 1.5g/cm 3 , 1.5g/cm 3 ⁇ 2.0g/cm 3 , 2.0g/cm 3 ⁇ 2.5g/cm 3 , 2.5g/cm 3 ⁇ 3.0g /cm 3 , 3.0g/cm 3 ⁇ 3.5g/cm 3 , 3.5g/cm 3 ⁇ 4.0g/cm 3 , 4.0g/cm 3 ⁇ 4.5g/cm 3 , 4.5g/cm 3 ⁇ 5.0g/cm 3. 5.0g/cm 3 ⁇ 5.5g/cm 3 , 5.5g/cm 3 ⁇ 6.0g/cm 3 , or 6.0g/cm 3 .
  • the fluorine-containing sulfonimide lithium salt may be a lithium salt with a chemical structural formula as shown in formula I:
  • R 1 and R 2 may be independently selected from a fluorine atom or an optionally fluorine-substituted hydrocarbon group having 1 to 8 carbon atoms, and at least one of R 1 and R 2 contains fluorine.
  • R 1 and R 2 may be independently selected from a fluorine atom, -CH 3 , -CHF 2 , -CH 2 F, -CF 3 ,- C 2 F 5 , -C 3 F 7 , -C 4 F 9 , or -CF 2 CF 2 OCF 2 CF 3 .
  • the fluorine-containing sulfonimide lithium salt may be selected from lithium bisfluorosulfonimide (LiFSI), lithium fluorosulfonyl (trifluoromethylsulfonyl) imide, bis(trifluoromethylsulfonyl) Lithium fluoromethyl)sulfonimide (LiTFSI), lithium methyltrifluoromethylsulfonimide, lithium trifluoromethyl(pentafluoroethyl)sulfonimide, bis(pentafluoroethyl)sulfonyl
  • the fluorine-containing sulfonimide lithium salt may include bisfluorosulfonimide lithium, or the fluorine-containing sulfonimide lithium salt may be selected from Lithium bisfluorosulfonimide.
  • the mass percentage C I of the first lithium salt (ie, fluorine-containing sulfonimide lithium salt, LiFSI) may be 4.0 wt% or higher , Preferably 5.0 wt% or higher, more preferably 5.5 wt% or higher.
  • the structural characteristics of the fluorine-containing sulfonimide lithium salt itself have higher electrical conductivity at room temperature, and are more stable than conventional lithium salts (LiPF 6 ), and are less sensitive to water and temperature .
  • the fluorine-containing sulfonimide lithium salt of the present application has higher chemical stability and electrochemical stability, and can be used to improve the stability and power performance of the electrolyte.
  • the relative content of the fluorine-containing sulfonimide lithium salt in the electrolyte in the present application is within the above range, the viscosity of the electrolyte can be prevented from increasing excessively, and the ion conductivity of the electrolyte can be effectively improved.
  • the electrolyte lithium salt may also include a second lithium salt.
  • the second lithium salt may be selected from one or a combination of inorganic lithium salts, organic lithium salts, and the like.
  • the second lithium salt may be selected from one or more of LiPF 6 , LiBF 4 , LiSbF 6 , LiAsF 6 , LiClO 4 and LiB(C 2 O 4 ) 2, etc.
  • the second lithium salt may be selected from one or a combination of LiPF 6 , LiBF 4 , LiPO 2 F 2 , Li 3 POF, etc., particularly preferably, the second lithium salt may include LiPF 6.
  • the second lithium salt is selected from LiPF 6 .
  • the inorganic fluorine-containing lithium salt is used as the main lithium salt or the content is too large, the film forming effect on the cathode is not good, so it will deteriorate high-temperature storage and gas production.
  • the conductivity of the electrolyte and the corrosion of the aluminum foil can be considered.
  • the molar ratio of the first lithium salt to the second lithium salt may be in the range of 1:1 to 20:1, more preferably, it may be in the range of 1.2:1 to 10:1, particularly preferably The ground may be in the range of 6:4-9:1, for example, the molar ratio of the first lithium salt to the second lithium salt may be 2:1-7:3, 7:3-3:1, 3:1-4 :1, 4:1 ⁇ 5:1, 5:1 ⁇ 6:1, 6:1 ⁇ 7:1, or 7:1 ⁇ 8:1.
  • the total concentration of lithium salt in the electrolyte may be 0.5 mol/L to 2.0 mol/L, 0.5 mol/L to 0.6 mol/L, 0.6 mol/L to 0.7 mol/L , 0.7mol/L ⁇ 0.8mol/L, 0.8mol/L ⁇ 0.9mol/L, 0.9mol/L ⁇ 1.0mol/L, 1.0mol/L ⁇ 1.1mol/L, 1.1mol/L ⁇ 1.2mol/L , 1.2mol/L ⁇ 1.3mol/L, 1.3mol/L ⁇ 1.4mol/L, 1.4mol/L ⁇ 1.5mol/L, 1.5mol/L ⁇ 1.6mol/L, 1.6mol/L ⁇ 1.7mol/L , 1.7mol/L ⁇ 1.8mol/L, 1.8mol/L ⁇ 1.9mol/L, or 1.9mol/L ⁇ 2.0mol/L, more preferably 0.6mol/L ⁇ 1.8mol/L, 0.7mol/L L ⁇ 1.7mol/L, or 0.8mol/L ⁇ 1.5mol/L.
  • the electrolyte may further include additives, and the oxidation potential of the additives included in the electrolyte may be suitable for forming a relatively stable passivation film on the surface of the positive electrode, and in the formation of passivation At the same time as the film, under the drive of potential, a dense protective film can be formed on the aluminum foil, which improves the corrosion resistance of the aluminum foil, which is beneficial to improve the safety performance and long-term cycle performance of the lithium ion battery.
  • the additive may be selected from one or more combinations of fluoroethylene carbonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium difluorobisoxalate phosphate, and the like.
  • the electrolyte may include an organic solvent, and the organic solvent is usually used as a solvent to form a solution system of the electrolyte.
  • the organic solvent included in the electrolyte may be various in the art.
  • an organic solvent suitable for lithium ion battery electrolyte may be dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), ethyl methyl carbonate (EMC) ), methyl propyl carbonate (MPC), ethylene propyl carbonate (EPC), vinyl ethylene carbonate (VEC), ethylene carbonate (EC), propylene carbonate (PC), gamma-butyrolactone (GBL), Butylene carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), ethyl formate, methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), propylene Methyl ester (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), sulfolane (SF), dimethyl sulfone
  • DMC dimethyl
  • the non-aqueous organic solvent includes cyclic carbonate
  • the content of the cyclic carbonate does not exceed 10% by weight
  • the cyclic carbonate may include five Ring, six-membered ring, seven-membered ring carbonate and seven-membered ring or more macrocyclic carbonates, specifically, for example, vinyl ethylene carbonate (VEC), ethylene carbonate (EC), propylene carbonate (PC), One or a combination of butene carbonate (BC), fluoroethylene carbonate (FEC), etc.
  • VEC vinyl ethylene carbonate
  • EC ethylene carbonate
  • PC propylene carbonate
  • BC butene carbonate
  • FEC fluoroethylene carbonate
  • the negative electrode sheet generally includes a negative electrode current collector and a negative electrode active material layer on the surface of the negative electrode current collector, and the negative electrode active material layer generally includes a negative electrode active material.
  • the negative active material may be various negative active materials suitable for lithium ion batteries in the art.
  • the negative active material may include one or more of artificial graphite, natural graphite, and the like.
  • the negative electrode active material may also include mesophase microcarbon spheres (MCMB), hard carbon, soft carbon, silicon, silicon-carbon composite, SiO, Li-Sn alloy, Li-Sn-O alloy, Sn, One or a combination of SnO, SnO 2 , spinel structure lithium titanate Li 4 Ti 5 O 12 , Li-Al alloy, and metallic lithium.
  • the negative electrode current collector can be a metal foil or porous metal plate.
  • the metal suitable for the negative electrode current collector can be copper, nickel, titanium, iron and other metals or their alloys.
  • the negative active material layer may also include a conductive agent, a binder, a thickener, and the like. If necessary, the negative pole piece may also include solvents or other additives.
  • the conductive agent, binder, and thickener in the negative active material layer can be various materials suitable for lithium ion batteries, and those skilled in the art can make selections according to actual needs.
  • the conductive agent may be one or more of graphite, superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers;
  • the binder may be styrene butadiene rubber (SBR), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinyl butyral (PVB), water-based acrylic resin (water-based acrylic resin) And one or more of carboxymethyl cellulose (CMC) and the like; for another example, the thickener may be carboxymethyl cellulose (CMC) and the like.
  • the compaction density and porosity of the negative electrode active material layer usually need to be within a suitable range, so that on the one hand, the volume energy density of the lithium ion battery can be high, and the negative electrode active material particles The compression deformation is low, which is conducive to the rapid infiltration of the electrolyte between the gaps of the negative pole pieces.
  • the compacted density PD A of the negative active material layer may be 1.5g/cm 3 ⁇ 2.1g/cm 3 , 1.5g/cm 3 ⁇ 1.6g/cm 3 , 1.6g /cm 3 ⁇ 1.65g/cm 3 , 1.65g/cm 3 ⁇ 1.7g/cm 3 , 1.7g/cm 3 ⁇ 1.8g/cm 3 , 1.8g/cm 3 ⁇ 1.9g/cm 3 , 1.9g/cm 3 to 2.0 g/cm 3 , or 2.0 g/cm 3 to 2.1 g/cm 3 , preferably 1.5 g/cm 3 to 1.65 g/cm 3 .
  • the porosity of the negative pole piece may be 10%-50%, 10%-15%, 15%-18%, 18%-20%, 20%-24%, 24%. % ⁇ 26%, 26% ⁇ 30%, 30% ⁇ 34%, 34% ⁇ 37%, 37% ⁇ 38%, 38% ⁇ 42%, 42% ⁇ 46%, or 46% ⁇ 50%, more preferably The land is 15% to 37%.
  • the upper limit of the floating physical resistance increase rate ⁇ R does not exceed 55, more preferably, the upper limit of the floating physical resistance increase rate ⁇ R does not exceed 50, most preferably, the The upper limit of the floating charge physical resistance increase rate ⁇ R does not exceed 30.
  • the positive electrode sheet generally includes a positive electrode current collector and a positive electrode active material layer on the surface of the positive electrode current collector, and the positive electrode active material layer generally includes a positive electrode active material.
  • the positive active material may be various positive active materials suitable for secondary batteries in the art.
  • the positive active material may include but not limited to lithium transition metal composite oxides, etc., more specifically, the lithium transition The metal composite oxide may include, but is not limited to, lithium iron phosphide, lithium iron manganese phosphide, lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide, lithium One or more combinations of nickel-cobalt-aluminum oxides or compounds obtained by adding other transition metals or non-transition metals to these lithium transition metal oxides.
  • the positive electrode current collector can be a metal foil or porous metal plate.
  • the metal suitable for the positive electrode current collector can be metals such as copper, aluminum, or their alloys.
  • the lithium ion battery provided in this application usually also includes an isolation film.
  • the isolation film may be various isolation film materials suitable for lithium ion batteries in the field. For example, it may include but not limited to polyethylene, polypropylene, One or more combinations of polyvinylidene fluoride, aramid, polyethylene terephthalate, polytetrafluoroethylene, polyacrylonitrile, polyimide, polyamide, polyester and natural fiber .
  • the positive pole piece, the separator and the negative pole piece can generally be used to form a cell of the lithium ion battery, for example, the positive pole piece, the separator
  • the membrane and the negative electrode piece can each be a layered body, which can be cut to a target size and stacked in sequence, and can be further combined with the electrolyte to form a lithium ion battery.
  • the positive pole piece, the separator film and the negative pole piece can be directly formed into a single laminate battery, and can be further wound to a target size to form a battery cell, and can be further combined with an electrolyte to form a lithium ion battery.
  • the lithium-ion battery is a single-layer laminated battery. On the one hand, such a battery is easier to operate during the floating charging process, and on the other hand, the screening cost is lower.
  • the lithium ion battery may also include various other components that can be used in a lithium ion battery.
  • applicable components may include, but are not limited to, packaging shells, tabs, and external electrodes.
  • Fig. 3 shows a perspective view of a battery module according to an embodiment of the present invention.
  • the battery module 4 according to the present invention includes a plurality of battery cells 5 arranged in a longitudinal direction.
  • the battery module 4 can be used as a power source or an energy storage device.
  • the number of battery cells 5 in the battery module 4 can be adjusted according to the application and capacity of the battery module 4.
  • FIG. 4 shows a perspective view of a battery pack according to an embodiment of the present application
  • FIG. 5 is an exploded view of the battery pack shown in FIG. 4.
  • the battery pack 1 includes an upper case 2, a lower case 3 and a battery module 4.
  • the upper case 2 and the lower case 3 are assembled together to form a space for accommodating the battery module 4.
  • the battery module 4 is placed in the space of the upper case 2 and the lower case 3 assembled together.
  • the output pole of the battery module 4 passes through one or between the upper case 2 and the lower case 3 to supply power to or charge from the outside.
  • the battery pack 1 can be used as a power source or an energy storage device.
  • the device includes the lithium ion battery of the first aspect of the present application.
  • the lithium ion battery can be used as a power source of the device, and can also be used as an energy storage unit of the device.
  • the device can be, but is not limited to, mobile devices (such as mobile phones, laptop computers, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf Vehicles, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.
  • the device in this application uses the lithium ion battery provided in this application, and therefore has at least the same advantages as the lithium ion battery.
  • Fig. 6 shows a schematic diagram of a lithium ion battery as a power supply device according to an embodiment of the present application.
  • the device using the battery cell 5 is an electric vehicle.
  • the device using the battery cell 5 can be any electric vehicle (e.g., electric bus, electric tram, electric bicycle, electric motorcycle, electric scooter, electric golf cart, electric truck), electric ship, Electric tools, electronic equipment and energy storage systems.
  • the device can select a lithium ion battery, battery module or battery pack according to its usage requirements.
  • the device may be a mobile phone, a tablet computer, a notebook computer, etc.
  • the device usually requires light and thin, and can use lithium-ion batteries as a power source.
  • the positive electrode active material LiNi 0.8 Co 0.1 Mn 0.1 O 2 , conductive carbon black SP and binder PVDF into the solvent NMP and mix uniformly to obtain the positive electrode slurry; uniformly coat the positive electrode slurry on the positive electrode current collector aluminum foil,
  • the coating weight of the positive electrode slurry is 0.309g/1540.25mm 2 (based on the weight excluding the solvent). After drying, cold pressing, slitting, and cutting, the positive electrode piece is obtained.
  • the positive electrode active material, conductive The mass ratio of carbon black and binder PVDF is 96:2:2.
  • the first lithium salt LiFSI and the second lithium salt LiPF 6 according to a certain molar ratio (the sum of lithium salt concentrations is 1M).
  • the organic solvent is ethylene carbonate and ethyl methyl carbonate, and the content of the cyclic carbonate (ethylene carbonate) is 20 wt%.
  • a 16 micron polyethylene film (PE) is used as the diaphragm.
  • the prepared positive electrode sheet, the separator, and the negative electrode sheet are stacked in order, so that the separator is in the middle of the positive and negative electrode sheets to separate the positive and negative electrodes, and the bare cell is obtained by winding.
  • After welding the tabs place the bare cells in the outer packaging, inject the electrolyte prepared above into the dried cells, encapsulate, stand still, form, shape, and test the capacity to complete the preparation of the lithium ion battery.
  • the soft-pack lithium-ion battery has a thickness of 4.0mm, a width of 60mm, and a length of 140mm. Among them, in the above-mentioned soft-packed lithium ion battery, the total mass of the negative electrode active material layer is 25 g, and the total mass of the electrolyte is 14 g.
  • the preparation methods of the positive pole piece, the negative pole piece, the electrolyte and the lithium ion battery in Examples 2-10 and Comparative Examples 1-3 are basically the same as those in Example 1.
  • the coating weight of the negative electrode slurry and the average particle size of the negative electrode active material are changed. diameter, made of other parameters such as cold pressure, adjusting the total mass of the negative active material M a, and the packing density PD a pole piece porosity P a, each of the Examples and Comparative Examples of the formulation and composition parameters in Table 1.
  • the capacity retention rate (%) of the lithium ion secondary battery after 100 cycles of 1C/1C at 45°C (discharge capacity at the 100th cycle/discharge capacity at the 1st cycle) ⁇ 100%.
  • the above-mentioned lithium ion secondary battery is left for 5 minutes, charged to 4.2V at a constant current rate of 1C, and then charged at a constant voltage until the current is less than or equal to 0.05C. Put it in an oven at 60°C and let it stand for 1 month.
  • the lithium ion secondary battery is taken out of the oven. Allow it to cool to room temperature, leave it aside for 5 minutes, charge it to 4.2V at a constant current rate of 1C, then charge it at a constant voltage until the current is less than or equal to 0.05C, then leave it aside for 5 minutes, then discharge it to 3.0V at a rate of 1C at a constant current rate, and record the discharge capacity Is the discharge capacity after storage.
  • the capacity retention rate (%) of the lithium ion secondary battery after storage at 60°C for 1 month (discharge capacity after storage/initial discharge capacity) ⁇ 100%.
  • the fresh lithium ion secondary batteries prepared in the examples and comparative examples were left for 5 minutes, charged to 4.2V at a constant current rate of 1C, and then charged at a constant voltage until the current was less than or equal to 0.05C.
  • the lithium ion secondary battery is placed in an oven, and the temperature is increased from 25°C to 130°C at a rate of 2°C per minute, and the temperature is maintained for 2 hours. During the monitoring of the temperature of the battery surface.
  • test results are analyzed below.
  • the electrolyte containing the fluorine-containing sulfonimide lithium salt as the first lithium salt is injected into the electrolyte, and the pores per unit volume in the negative pole piece can be adjusted to accommodate the fluorine-containing sulfonimide.
  • the content of lithium salt can ultimately achieve high safety and excellent cycle performance.
  • Comparative Example 1 and Comparative Example 3 it can be seen from Comparative Example 1 and Comparative Example 3 that when the electrolyte does not contain fluorine-containing sulfonimide lithium salt, or the content of fluorine-containing sulfonimide lithium salt per unit volume of pores in the negative electrode is too low , The side reaction of lithium-ion batteries in the high temperature or high full charge state is intensified, the gas production of the battery increases, and the heat production increases, which further deteriorates the safety and high temperature cycle and storage.
  • the organic solvent in the electrolyte preferably contains no more than 10 wt% of the cyclic carbonate.
  • the aim is to reduce the solvent gas production on the surface of the positive electrode.
  • characteristic additives such as fluoroethylene carbonate, lithium difluorophosphate, lithium difluorooxalate borate, etc., it can further improve the corrosion resistance of the positive aluminum foil surface, as well as the film-forming effect, and inhibit the floating resistivity of lithium-ion batteries. Increase and improve circulation and gas production problems
  • this application effectively overcomes various shortcomings in the prior art and has a high industrial value.

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Abstract

本申请公开了一种锂离子电池及其相关的电池模块、电池包和装置。该锂离子电池包括正极极片、负极极片、隔离膜和电解液，所述负极极片包括含有负极活性物质的负极活性物质层，所述电解液包括电解质锂盐，所述电解质锂盐包括第一锂盐，所述第一锂盐选自含氟磺酰亚胺锂盐，所述第一锂盐与所述负极极片满足关系式(1)。本申请的锂离子电池具有安全性能高、循环寿命长、高温存储好的优异性能。

Description

一种锂离子电池及其相关的电池模块、电池包和装置
本申请要求享有2019年07月30日提交的名称为“一种锂离子电池”的中国专利申请CN201910695499.5的优先权，其全部内容通过引用并入本文中。
技术领域
本申请涉及电池技术领域，尤其涉及一种锂离子电池及其相关的电池模块、电池包和装置。
背景技术
锂离子电池自20世纪末量产以来，凭借其比能量高、无记忆效应、循环寿命长等优点，已被广泛用于消费电子领域。近年来，全球环保形势日益严峻，石化燃料的紧缺问题也愈发严重，所以，随着材料及工艺的不断成熟，锂离子电池作为一种清洁能源逐渐成为汽车的一种重要动力来源。
常用的动力电池，多以磷酸铁锂、镍钴锰酸锂三元材料为正极活性物质。磷酸铁锂结构稳定、活性低，能够提供高安全性及长循环寿命，但是其平台低、比能量低，能量密度往往无法满足日益增长的电动汽车续航里程需求。镍钴锰酸锂三元材料则结合了镍酸锂、钴酸锂、锰酸锂三者的优点，寿命、能量密度优势明显，但是该三元材料自身结构不够稳定，且呈碱性，在以六氟磷酸锂为主盐的电解液中，受其中微量HF的影响，安全性能难以保证，而在热冲击过程中则极易发生热失控。相比于六氟磷酸锂，双氟磺酰亚胺锂(LiFSI)中F元素含量较低且热稳定性好，能够提供优异的电池安全性，但过高含量的LiFSI，极易造成电池耐高电压性能变差。
发明内容
鉴于以上所述现有技术的缺点，本申请的目的在于提供一种具有耐高电压性能的锂离子电池，用于解决现有技术中的问题。
为实现上述目的及其他相关目的，本申请一方面提供一种锂离子电池，包括正极极片、 负极极片、隔离膜和电解液，所述负极极片包括含有负极活性物质的负极活性物质层，所述电解液包括电解质锂盐，所述电解质锂盐包括第一锂盐，所述第一锂盐选自含氟磺酰亚胺锂盐，所述第一锂盐与所述负极极片满足关系式(1)(g/cm 3)：
Figure PCTCN2020100291-appb-000001
其中，M E为所述锂离子电池中所述电解液的总质量，单位为g；
C I为所述第一锂盐相对于所述电解液的质量百分比，单位为％；
M A为所述锂离子电池中所述负极活性物质层的总质量，单位为g；
PD A为所述负极活性物质层的压实密度，单位为g/cm 3；
P A为所述负极活性物质层的孔隙率，单位为％。
在第二方面，本申请提供了一种电池模块，其包括本申请第一方面所述的锂离子电池。
在第三方面，本申请提供了一种电池包，其包括本申请第二方面所述的电池模块。
在第四方面，本申请还提供了一种装置，其包括本申请第一方面所述的锂离子电池。
相对于现有技术，本申请的有益效果为：
本申请采用含氟磺酰亚胺锂盐作为第一锂盐的电解液，并且控制负极极片中单位体积孔隙中可容纳含氟磺酰亚胺锂盐的含量在一定的范围内，可以有效抑制电池的阻抗增加过快或浓度极化过大，能够充分发挥含氟磺酰亚胺锂盐的高温优势和高电导率优势，形成的电池浮充物理电阻增加率较低，避免在循环中后期产生析锂等安全问题，最终达到安全性能高、循环寿命长、高温存储好的优异性能。
附图说明
图1是本申请的锂离子电池的一实施方式的示意图。
图2是本申请的锂离子电池的一实施方式的分解示意图。
图3是电池模块的一实施方式的示意图。
图4是电池包的一实施方式的示意图。
图5是图4的分解图。
图6是本申请的锂离子电池用作电源的装置的一实施方式的示意图。
其中，附图标记说明如下：
1-电池包
2-上箱体
3-下箱体
4-电池模块
5-锂离子电池
51-壳体
52-电极组件
53-盖板。
具体实施方式
为了使本申请的目的、技术方案及优点更加清楚明白，以下结合附图及实施例，对本申请进行进一步详细说明。应当理解，此处所描述的具体实施例仅仅用以解释本申请，并不用于限定本申请。
为了简明，本文仅具体地公开了一些数值范围。然而，任意下限可以与任何上限组合形成未明确记载的范围；以及任意下限可以与其它下限组合形成未明确记载的范围，同样任意上限可以与任意其它上限组合形成未明确记载的范围。此外，每个单独公开的点或单个数值自身可以作为下限或上限与任意其它点或单个数值组合或与其它下限或上限组合形成未明确记载的范围。
在本文的描述中，需要说明的是，除非另有说明，“以上”、“以下”为包含本数，“一种或几种”中“几种”的含义是两种及两种以上。
除非另有说明，本申请中使用的术语具有本领域技术人员通常所理解的公知含义。除非另有说明，本申请中提到的各参数的数值可以用本领域常用的各种测量方法进行测量 (例如，可以按照在本申请的实施例中给出的方法进行测试)。
锂离子电池
下面详细说明本申请的锂离子电池。
本申请第一方面提供一种锂离子电池(也称为锂离子二次电池)，包括正极极片、负极极片、隔离膜和电解液，所述负极极片包括含有负极活性物质的负极活性物质层，所述电解液包括电解质锂盐，所述电解质锂盐包括第一锂盐，所述第一锂盐选自含氟磺酰亚胺锂盐，所述第一锂盐与所述负极极片满足关系式(1)(g/cm 3)：
Figure PCTCN2020100291-appb-000002
其中，M E为所述锂离子电池中所述电解液的总质量，单位为g；C I为所述第一锂盐相对于所述电解液的质量百分比，单位为％；M A为所述锂离子电池中所述负极活性物质层的总质量，单位为g；PD A为所述负极活性物质层的压实密度，单位为g/cm 3；P A为所述负极活性物质层的孔隙率，单位为％。
本申请中，为了解决电解液中微量HF可能给三元材料带来的安全风险，以F元素含量较低的锂盐作电解液主盐，其中，含氟磺酰亚胺锂盐中F元素相对含量较低且热稳定性好，产生的HF含量更少，可以有效抑制正极材料的产气问题，能够提供优异的电池安全性，此外，含氟磺酰亚胺锂盐在配制成电解液以后电导率高于六氟磷酸锂系电解液，在循环和存储寿命上均表现出明显优势。
本申请所提供的锂离子电池中，当电解液中含氟磺酰亚胺锂盐的浓度过高时，可能会引起电解液的粘度升高、流动性变差，影响到该物质在锂离子电池中的广泛应用。所以本申请中，根据负极极片的微观结构特征，调控负极活性物质层中单位体积孔隙中可容纳含氟磺酰亚胺锂盐的含量在一定的范围内，通过控制负极活性物质层的保液量，控制含氟磺酰亚胺锂盐在负极活性物质层的流动性，有效抑制高安全性电解液被快速消耗，抑制电池的阻抗增加过快或浓度极化过大，避免在循环中后期产生析锂等安全问题。
在本申请的一些实施方式中，所述负极活性物质层中单位体积孔隙中含氟磺酰亚胺锂盐的含量可以为0.6g/cm 3～6.2g/cm 3、0.6g/cm 3～1.0g/cm 3、1.0g/cm 3～1.5g/cm 3、1.5g/cm 3～2.0g/cm 3、2.0g/cm 3～2.5g/cm 3、2.5g/cm 3～3.0g/cm 3、3.0g/cm 3～3.5g/cm 3、3.5g/cm 3～4.0g/cm 3、4.0g/cm 3～4.5g/cm 3、4.5g/cm 3～5.0g/cm 3、5.0g/cm 3～5.5g/cm 3、5.5g/ cm 3～6.0g/cm 3、或6.0g/cm 3～6.2g/cm 3。
本申请所提供的锂离子电池中，含氟磺酰亚胺锂盐可以是化学结构式如式I所示的锂盐：
Figure PCTCN2020100291-appb-000003
其中，R 1和R 2可以分别独立地选自氟原子、或可选地氟取代的碳原子数为1～8的烃基基团，并且R 1和R 2中至少一个包含氟。优选的，R 1和R 2可以分别独立地选自-C aH bF c或-CF 2CF 2(OCF 2CF 2) dF，其中，a为0、1、2、3、4、5、6、7、或8，b和c为整数，且b+c＝2a+1，并且d为1、2或3。更优选的，a为0、1、2、3或4，例如，R 1和R 2可以分别独立地选自氟原子、-CH 3、-CHF 2、-CH 2F、-CF 3、-C 2F 5、-C 3F 7、-C 4F 9、或-CF 2CF 2OCF 2CF 3。
在本申请一些优选的实施方式中，含氟磺酰亚胺锂盐可以选自双氟磺酰亚胺锂(LiFSI)、氟磺酰(三氟甲基磺酰)亚胺锂、双(三氟甲基)磺酰亚胺锂(LiTFSI)、甲基三氟甲基磺酰亚胺锂、三氟甲基(五氟乙基)磺酰亚胺锂、双(五氟乙基)磺酰亚胺锂等中的一种或多种，最优选地，所述含氟磺酰亚胺锂盐可以包含双氟磺酰亚胺锂、或所述含氟磺酰亚胺锂盐可以选自双氟磺酰亚胺锂。
本申请所提供的锂离子电池中，相对于所述电解液的总质量，第一锂盐(即含氟磺酰亚胺锂盐，LiFSI)的质量百分比C I可以为4.0wt％或更高，优选可以为5.0wt％或更高，更优选可以为5.5wt％或更高。本申请中，含氟磺酰亚胺锂盐本身的结构特性，其在常温下具有较高的电导率，并且比常规的锂盐(LiPF 6)更稳定，对水以及温度的敏感度较低。因此，本申请的含氟磺酰亚胺锂盐具有较高的化学稳定性和电化学稳定性，可以用于提高电解液的稳定性和功率性能。本申请中的含氟磺酰亚胺锂盐在电解液中的相对含量在上述范围时，可以避免电解液的粘度升高过大、同时有效提高电解液的导离子性能。
本申请所提供的锂离子电池中，电解质锂盐还可以包含第二锂盐。所述第二锂盐可以选自无机锂盐、有机锂盐等中的一种或多种的组合。在本申请一些实施方式中，所述第二锂盐可以选自LiPF 6、LiBF 4、LiSbF 6、LiAsF 6、LiClO 4和LiB(C 2O 4) 2等中的一种或多种，更优选的，所述第二锂盐可以选自LiPF 6、LiBF 4、LiPO 2F 2、Li 3POF等中的一种或多种的组合，尤其优选的，所述第二锂盐可以包括LiPF 6、或所述第二锂盐选自LiPF 6。
申请人经过研究发现，无机含氟锂盐作为第二锂盐在首次充电时，部分锂盐分解产生氟离子，氟离子与铝箔反应生成氟化铝钝化层，进而起到抑制腐蚀铝箔的作用。经研究发现，无机含氟锂盐在总锂盐中含量大于10mol％时(摩尔比)，可以有效抑制铝箔腐蚀。但是无机含氟锂盐作为主要锂盐或者含量过大时，在阴极成膜效果不好，因此会恶化高温存储产气。因此，采用含氟磺酰亚胺锂盐作为第一锂盐，无机含氟锂盐作为第二锂盐时，可以兼顾电解液的电导率以及铝箔腐蚀问题。在本申请一些实施方式中，第一锂盐与第二锂盐的摩尔比可以在1:1～20:1范围内，更优选地，可以在1.2:1～10:1范围内，尤其优选地可以在6:4～9:1范围内，例如，第一锂盐与第二锂盐的摩尔比可以是2:1～7:3、7:3～3:1、3:1～4:1、4:1～5:1、5:1～6:1、6:1～7:1、或7:1～8:1。
在本申请一些优选的实施方式中，锂盐在电解液中的总浓度可以为0.5mol/L～2.0mol/L、0.5mol/L～0.6mol/L、0.6mol/L～0.7mol/L、0.7mol/L～0.8mol/L、0.8mol/L～0.9mol/L、0.9mol/L～1.0mol/L、1.0mol/L～1.1mol/L、1.1mol/L～1.2mol/L、1.2mol/L～1.3mol/L、1.3mol/L～1.4mol/L、1.4mol/L～1.5mol/L、1.5mol/L～1.6mol/L、1.6mol/L～1.7mol/L、1.7mol/L～1.8mol/L、1.8mol/L～1.9mol/L、或1.9mol/L～2.0mol/L，进一步优选的可以为0.6mol/L～1.8mol/L、0.7mol/L～1.7mol/L、或0.8mol/L～1.5mol/L。
本申请所提供的锂离子电池中，所述电解液中还可以进一步包括添加剂，电解液中所包括的添加剂的氧化电位可以适于在正极表面形成较为稳定的钝化膜，并且在形成钝化膜的同时，在电位的驱动下，能够在铝箔上形成致密的保护膜，提升铝箔耐腐蚀性，有利于提高锂离子电池的安全性能以及长期循环性能。在本申请一些实施方式中，所述添加剂可以选自氟代碳酸乙烯酯、二氟磷酸锂、二氟草酸硼酸锂、二氟双草酸磷酸锂等中的一种或多种的组合。
本申请所提供的锂离子电池中，所述电解液中可以包括有机溶剂，所述有机溶剂通常作为溶剂以形成电解液的溶液体系，所述电解液中所包括的有机溶剂可以是本领域各种适用于锂离子电池电解液的有机溶剂，例如，所述有机溶剂可以是碳酸二甲酯(DMC)、碳酸二乙酯(DEC)、碳酸二丙酯(DPC)、碳酸甲乙酯(EMC)、碳酸甲丙酯(MPC)、碳酸乙丙酯(EPC)、碳酸乙烯亚乙酯(VEC)、碳酸乙烯酯(EC)、碳酸丙烯酯(PC)、γ-丁内酯(GBL)、碳酸丁烯酯(BC)、氟代碳酸乙烯酯(FEC)、甲酸甲酯(MF)、甲酸乙酯、乙酸甲酯(MA)、乙酸乙酯(EA)、乙酸丙酯(PA)、丙酸甲酯(MP)、丙酸乙酯(EP)、丙酸丙酯(PP)、丁酸甲酯(MB)、丁酸乙酯(EB)、环丁砜(SF)、二甲砜(MSM)、甲乙砜(EMS)、二乙砜(ESE)、四氢呋喃(THF)和亚硫酸亚丙酯等中的一种或多种的组合。在本申请的一些优选实施方式中，当所述非水有机溶 剂包括环状碳酸酯(cyclic carbonate)时，所述环状碳酸酯的含量不超过10wt％，所述环状碳酸酯可以包括五元环、六元环、七元环碳酸酯以及七元环以上的大环碳酸酯，具体可以是例如碳酸乙烯亚乙酯(VEC)、碳酸乙烯酯(EC)、碳酸丙烯酯(PC)、碳酸丁烯酯(BC)、氟代碳酸乙烯酯(FEC)等中的一种或多种的组合。这是由于当电解液中含有高浓度的含氟磺酰亚胺锂盐时，有机溶剂若为环状碳酸酯过高时可能会引起电解液在阴极的副反应增加，产气明显增大，引发锂离子电池的安全及循环过程中的产气问题。
本申请所提供的锂离子电池中，所述负极极片通常包括负极集流体和位于负极集流体表面的负极活性物质层，所述负极活性物质层通常包括负极活性物质。所述负极活性物质可以是本领域各种适用于锂离子电池的负极活性物质，例如，所述负极活性物质可以包括人造石墨、天然石墨等中的一种或多种的选择。优选的，所述负极活性物质还可以包括中间相微碳球(MCMB)、硬碳、软碳、硅、硅-碳复合物、SiO、Li-Sn合金、Li-Sn-O合金、Sn、SnO、SnO 2、尖晶石结构的钛酸锂Li 4Ti 5O 12、Li-Al合金及金属锂等中的一种或多种的组合。所述负极集流体可以是金属箔材或多孔金属板等材料，例如，适用于负极集流体的金属可以是铜、镍、钛、铁等金属或它们的合金。
本申请所提供的锂离子电池中，负极活性物质层还可以包括导电剂、粘结剂和增稠剂等。视需要，所述负极极片中还可以包括溶剂或其他添加剂等。所述负极活性物质层中的导电剂、粘结剂、增稠剂可以是各种适用于锂离子电池的物质，本领域技术人员可以根据实际需求进行选择。例如，所述导电剂可以是石墨、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等中的一种或多种；再例如，所述粘结剂可以是丁苯橡胶(SBR)、聚偏二氟乙烯(PVDF)、聚四氟乙烯(PTFE)、聚乙烯醇缩丁醛(PVB)、水性丙烯酸树脂(water-based acrylic resin)及羧甲基纤维素(CMC)等中的一种或多种；再例如，所述增稠剂可以是羧甲基纤维素(CMC)等。
本申请所提供的锂离子电池中，负极活性物质层的压实密度和孔隙率通常需要在合适的范围内，从而一方面可以保证锂离子电池的体积能量密度较高，同时对负极活性物质颗粒的压缩变形量较低，有利于电解液在负极极片空隙间快速浸润。在本申请一些优选的实施方式中，所述负极活性物质层的压实密度PD A可以为1.5g/cm 3～2.1g/cm 3、1.5g/cm 3～1.6g/cm 3、1.6g/cm 3～1.65g/cm 3、1.65g/cm 3～1.7g/cm 3、1.7g/cm 3～1.8g/cm 3、1.8g/cm 3～1.9g/cm 3、1.9g/cm 3～2.0g/cm 3、或2.0g/cm 3～2.1g/cm 3，优选为1.5g/cm 3～1.65g/cm 3。在本申请另一些优选的实施方式中，负极极片的孔隙率可以为10％～50％、10％～15％、15％～18％、18％～20％、20％～24％、24％～26％、26％～30％、30％～34％、34％～37％、37％～38％、38％～42％、 42％～46％、或46％～50％，更优选地为15％～37％。
锂离子电池在充满电后，理论上充电过程已经终止，但在实际情况下，电池的电压会因其内部的自放电而逐步降低，浮充既是以小电流对锂离子电池持续地充电，以保持电池的满充状态。当锂离子电池长时间连续的经受浮充电时，电池长时间处于高度充电状态，此时电解液更容易发生分解，而含氟磺酰亚胺盐的阴离子在高电压下对正极集流体的腐蚀速率也会加快，从而增加锂离子电池的电阻，降低电池的长期循环性能及安全性能。
本申请所提供的锂离子电池中，用浮充物理电阻增加率ΔR反映浮充前后的锂离子电池的物理电阻的变化率，具体可以由如下方法计算获得：ΔR＝(R2-R1)/R1，其中，R1为锂离子电池的1kHz的物理电阻，R2为锂离子电池以1C恒流充电至额定电压、在所述额定电压下恒压充电至电流为0.1C，并在所述额定电压下恒压充电24h以后，所述锂离子电池的1kHz下的物理电阻。在本申请一优选实施方式中，所述浮充物理电阻增加率ΔR的上限不超过55，更为优选地，所述浮充物理电阻增加率ΔR的上限不超过50，最为优选地，所述浮充物理电阻增加率ΔR的上限不超过30。
本申请所提供的锂离子电池中，所述正极极片通常包括正极集流体和位于正极集流体表面的正极活性物质层，所述正极活性物质层通常包括正极活性物质。所述正极活性物质可以是本领域各种适用于二次电池的正极活性物质，例如，所述正极活性物质可以是包括但不限于锂过渡金属复合氧化物等，更具体的，所述锂过渡金属复合氧化物可以是包括但不限于锂铁磷化物、锂铁锰磷化物、锂钴氧化物、锂镍氧化物、锂锰氧化物、锂镍锰氧化物、锂镍钴锰氧化物、锂镍钴铝氧化物或这些锂过渡金属氧化物添加其他过渡金属或非过渡金属得到的化合物等中的一种或多种的组合。所述正极集流体可以是金属箔材或多孔金属板等材料，例如，适用于正极集流体的金属可以是铜、铝等金属或它们的合金。
本申请所提供的锂离子电池中，通常还包括隔离膜，所述隔离膜可以是本领域各种适用于锂离子电池的隔离膜材料，例如，可以是包括但不限于聚乙烯、聚丙烯、聚偏氟乙烯、芳纶、聚对苯二甲酸乙二醇酯、聚四氟乙烯、聚丙烯腈、聚酰亚胺，聚酰胺、聚酯和天然纤维等中的一种或多种的组合。
本申请所提供的锂离子电池中，所述锂离子电池中，所述正极极片、隔离膜和负极极片通常可以用于形成锂离子电池的电芯，例如，所述正极极片、隔离膜和负极极片各自都可以是层体，从而可以裁剪成目标尺寸后依次叠放，并可以进一步与电解液结合以形成锂离子电池。正极极片、隔离膜和负极极片可以直接形成单层叠片电池，还可以进一步卷绕至目标尺寸，以用于形成电芯，并可以进一步与电解液结合以形成锂离子电池。但在本申 请一优选实施方式中，所述锂离子电池是单层叠片电池，这样的电池，一方面浮充过程中更易操作，另一方面筛选成本更低。所述锂离子电池还可以包括其他各种可以用于锂离子电池的部件，例如，适用的部件可以是包括但不限于包装壳、极耳、外接电极等。
电池模块
接下来简单描述根据本发明第二个方面的电池模块。
图3示出了根据本发明一实施例的电池模块的立体图。参看图3，根据本发明的电池模块4包括多个电池单体5，所述多个电池单体5沿纵向排列。
电池模块4可以作为电源或储能装置。电池模块4中的电池单体5的数量可以根据电池模块4的应用和容量进行调节。
电池包
接下来将简单描述根据本申请第三方面的电池包。
图4示出了根据本申请一实施例的电池包的立体图，图5是图4所示电池包的分解图。
参看图4和图5，根据本申请的电池包1包括上箱体2、下箱体3以及电池模块4。其中，上箱体2和下箱体3组装在一起并形成收容电池模块4的空间。电池模块4置于组装在一起的上箱体2和下箱体3的空间内。
电池模块4的输出极从上箱体2和下箱体3的其中之一或二者之间穿出，以向外部供电或从外部充电。
需要说明的是，电池包1采用的电池模块4的数量和排列可以依据实际需要来确定。电池包1可以作为电源或储能装置。
装置
接下来将简单描述根据本申请第四方面的装置。该装置包括本申请第一方面的锂离子电池。所述锂离子电池可以用作装置的电源，也可以用作所述装置的能量存储单元。所述装置可以但不限于是移动设备(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。
本申请的装置采用了本申请所提供的锂离子电池，因此至少具有与所述锂离子电池相同的优势。
图6示出了根据本申请一实施例的锂离子电池作为电源装置的示意图。仅作为例举，在图6中，使用电池单体5的装置为电动汽车。使用电池单体5的装置可以为除电动汽车外的任何电动车辆(例如电动大巴、电动有轨电车、电动自行车、电动摩托车、电动踏板车、电动高尔夫球车、电动卡车)、电动船舶、电动工具、电子设备及储能系统。
所述装置可以根据其使用需求来选择锂离子电池、电池模块或电池包。
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，可以采用锂离子电池作为电源。
以下通过特定的具体实例说明本申请的实施方式，本领域技术人员可由本说明书所揭露的内容轻易地了解本申请的其他优点与功效。本申请还可以通过另外不同的具体实施方式加以实施或应用，本说明书中的各项细节也可以基于不同观点与应用，在没有背离本申请的精神下进行各种修饰或改变。
须知，下列实施例中未具体注明的工艺设备或装置均采用本领域内的常规设备或装置。
此外应理解，本申请中提到的一个或多个方法步骤并不排斥在所述组合步骤前后还可以存在其他方法步骤或在这些明确提到的步骤之间还可以插入其他方法步骤，除非另有说明；还应理解，本申请中提到的一个或多个设备/装置之间的组合连接关系并不排斥在所述组合设备/装置前后还可以存在其他设备/装置或在这些明确提到的两个设备/装置之间还可以插入其他设备/装置，除非另有说明。而且，除非另有说明，各方法步骤的编号仅为鉴别各方法步骤的便利工具，而非为限制各方法步骤的排列次序或限定本申请可实施的范围，其相对关系的改变或调整，在无实质变更技术内容的情况下，当亦视为本申请可实施的范畴。
实施例1
正极极片的制备：
将正极活性物质LiNi 0.8Co 0.1Mn 0.1O 2、导电炭黑SP及粘结剂PVDF分散至溶剂NMP中进行混合均匀，得到正极浆料；将正极浆料均匀涂布于正极集流体铝箔上，正极浆料的涂布重量为0.309g/1540.25mm 2(以不包含溶剂的重量计)，经烘干、冷压、分条、裁片后，得到正极极片，其中，正极活性物质、导电炭黑及粘结剂PVDF的质量比为96:2:2。
负极极片的制备：
将负极活性物质天然石墨、导电炭黑SP、增稠剂CMC及粘结剂SBR按照质量比96:1:1:2分散于溶剂去离子水中进行混合均匀，得到负极浆料；将负极浆料均匀涂布于负极集流体铜箔上；经烘干、冷压、分条、裁片，调节冷压压力在120～250吨，负极浆料的涂布重量在0.15g/1540.25mm 2(以不包含溶剂的重量计)，以及负极活性物质颗粒粒径Dv50在14μm，得到压实密度为1.5g/cm 3、孔隙率为30％的负极极片。其中，负极极片的压实密度可以通过公式P＝m/v计算得出(m为负极活性物质层的重量，单位为g；v为负极活性物质层的体积，单位为cm 3，v可以是负极活性物质层的面积与负极活性物质层的厚度的乘积)；负极极片的孔隙率可以使用AccuPyc II 1340真实密度仪根据仪器说明书进行测试。
电解液的制备：
在充满氩气的手套箱中(水含量＜10ppm，氧气含量＜1ppm)，将第一锂盐LiFSI和第二锂盐LiPF 6按照一定的摩尔比(锂盐浓度之和为1M)加入到含有非水有机溶剂中，有机溶剂为碳酸乙烯酯、碳酸甲乙酯，且环状碳酸酯(碳酸乙烯酯)含量为20wt％。待锂盐完全溶解后，加入适量其他添加剂。搅拌均匀后得到锂盐浓度为1.0mol/L的电解液。
隔膜的制备：
以16微米的聚乙烯薄膜(PE)作为隔膜。
锂离子电池的制备：
将制得的正极片、隔膜、负极片按顺序叠好，使隔膜处于正负极片中间起到隔离正负极的作用，卷绕得到裸电芯。焊接极耳后，将裸电芯置于外包装中，将上述制备的电解液注入到干燥后的电芯中，封装、静置、化成、整形、容量测试等，完成锂离子电池的制备。软包锂离子电池的厚度4.0mm、宽度60mm、长度140mm。其中，上述软包锂离子电池中，负极活性物质层的总质量为25g，电解液的总质量为14g。
实施例2-10以及对比例1-3
实施例2-10以及对比例1-3中正极极片、负极极片、电解液及锂离子电池的制备方法与实施例1基本相同，改变负极浆料的涂布重量、负极活性物质平均粒径、制成参数如冷压压力等，调节负活性物质总质量M A、压实密度PD A以及极片孔隙率P A，各实施例 及对比例的配方和物性参数参见表1。
表1
Figure PCTCN2020100291-appb-000004
测试方法：
(1)锂离子二次电池的循环性能测试：
在45℃下，将实施例和对比例制备得到的新鲜锂离子二次电池搁置5分钟，以1C倍率恒流充电至4.2V，再恒压充电至电流小于等于0.05C，之后搁置5分钟，再以1C倍率恒流放电至2.8V，此为一个循环充放电过程，此次的放电容量记为锂离子二次电池第1次循环的放电容量。将锂离子二次电池按照上述方法进行100次循环充放电测试，记录每一次循环的放电容量。
锂离子二次电池45℃1C/1C循环100次后的容量保持率(％)＝(第100次循环的放电容量/第1次循环的放电容量)×100％。
(2)锂离子二次电池的高温存储测试：
在25℃下，将实施例和对比例制备得到的新鲜锂离子二次电池搁置5分钟，以1C倍率恒流充电至4.2V，再恒压充电至电流小于等于0.05C，之后搁置5分钟，再以1C倍率恒流放电至2.8V，记录放电容量为初始放电容量。
将上述锂离子二次电池继续搁置5分钟，以1C倍率恒流充电至4.2V，再恒压充电至电流小于等于0.05C。再将其放入60℃烘箱中，搁置1个月。
搁置完成后，将上述锂离子二次电池从烘箱取出。待其冷却至室温，搁置5分钟，以1C倍率恒流充电至4.2V，再恒压充电至电流小于等于0.05C，之后搁置5分钟，再以1C倍率恒流放电至3.0V，记录放电容量为存储后的放电容量。
锂离子二次电池60℃存储1个月后的容量保持率(％)＝(存储后的放电容量/初始放电容量)×100％。
(3)锂离子二次电池的热冲击测试：
在25℃下，将实施例和对比例制备得到的新鲜锂离子二次电池搁置5分钟，以1C倍率恒流充电至4.2V，再恒压充电至电流小于等于0.05C。
将上述锂离子二次电池放置于烘箱中，以2℃每分钟的速率从25℃升温至130℃，保温2小时。期间监控电池表层的温度。
(4)锂离子电池浮充和物理电阻测试：
取含有待筛选正极极片的电池，测试其1kHz的物理电阻，记录为R1；以1C恒流充电至4.2V，然后以4.2V电压恒压充电至电流为0.1C，并继续在4.2V电压下恒压充电24h后，测试其1kHz的物理电阻，记录为R2。
锂离子电池的浮充物理电阻增加率ΔR＝(R2-R1)/R1。
各实施例及对比例的性能测试结果参见表2：
表2
Figure PCTCN2020100291-appb-000005
下面对测试结果进行分析。
从实施例1～10可以看出，将含氟磺酰亚胺锂盐为第一锂盐的电解液注入到电解液中，并调控负极极片中单位体积孔隙可容纳含氟磺酰亚胺锂盐的含量，能够最终达到高安全、优循环的性能效果。
由对比例1和对比例3可以看出，当电解液中不含含氟磺酰亚胺锂盐，或者负极极片中单位体积孔隙可容纳含氟磺酰亚胺锂盐的含量过低时，锂离子电池在高温或高满充状态下的副反应加剧，电池的产气量增大、产热增加，进而恶化安全及高温循环、存储。
由对比例2可以看出，当负极极片中单位体积孔隙可容纳含氟磺酰亚胺锂盐的含量过高时，由于含氟磺酰亚胺锂盐本身密度较大，制成的电解液粘度相对较高，一方面导致锂离子传输效果急剧降低，同时还会加速对正极集流体铝箔的腐蚀，导致电池极化极大增加，浮充电阻增加量过高，锂离子电池的循环容量保持率降低，不利于制成优循环的电池。
由实施例7～9可以进一步发现，电解液中的有机溶剂优选环状碳酸酯含量不超过10wt％。旨在降低溶剂在正极表面的产气。并且当进一步引入氟代碳酸乙烯酯、二氟磷酸锂、二氟草酸硼酸锂等特征添加剂时，能够进一步提升正极铝箔表面的耐腐蚀性，以及成膜效果，抑制锂离子电池浮充电阻率的增加、改善循环和产气问题
综上所述，本申请有效克服了现有技术中的种种缺点而具高度产业利用价值。
上述实施例仅例示性说明本申请的原理及其功效，而非用于限制本申请。任何熟悉此技术的人士皆可在不违背本申请的精神及范畴下，对上述实施例进行修饰或改变。因此，举凡所属技术领域中具有通常知识者在未脱离本申请所揭示的精神与技术思想下所完成的一切等效修饰或改变，仍应由本申请的权利要求所涵盖。

Claims (19)

  1. 一种锂离子电池，包括正极极片、负极极片、隔离膜和电解液，所述负极极片包括含有负极活性物质的负极活性物质层，所述电解液包括电解质锂盐，其中：
    所述电解质锂盐包括第一锂盐，所述第一锂盐选自含氟磺酰亚胺锂盐，
    所述第一锂盐与所述负极极片满足关系式(1)：
    Figure PCTCN2020100291-appb-100001
    其中，M E为所述锂离子电池中所述电解液的总质量，单位为g；
    C I为所述第一锂盐相对于所述电解液的质量百分比，单位为％；
    M A为所述锂离子电池中所述负极活性物质层的总质量，单位为g；
    PD A为所述负极活性物质层的压实密度，单位为g/cm 3；
    P A为所述负极活性物质层的孔隙率，单位为％。
  2. 根据权利要求1所述的锂离子电池，其中，所述负极活性物质层中单位体积孔隙中含氟磺酰亚胺锂盐的含量为0.6g/cm 3～6.2g/cm 3。
  3. 根据权利要求1或2所述的锂离子电池，其中，所述含氟磺酰亚胺锂盐是化学结构式如式I所示的锂盐：
    Figure PCTCN2020100291-appb-100002
    其中，R 1和R 2可以分别独立地选自氟原子、或可选地氟取代的碳原子数为1～8的烃基基团，并且R 1和R 2中至少一个包含氟。
  4. 根据权利要求3所述的锂离子电池，其中，式I中，R 1和R 2可以分别独立地选自 -C aH bF c或-CF 2CF 2(OCF 2CF 2) dF，其中，a为0、1、2、3、4、5、6、7或8，b和c为整数，且b+c＝2a+1，并且d为1、2或3。
  5. 根据权利要求1至4中任一项所述的锂离子电池，其中，含氟磺酰亚胺锂盐选自双氟磺酰亚胺锂(LiFSI)、氟磺酰(三氟甲基磺酰)亚胺锂、双(三氟甲基)磺酰亚胺锂(LiTFSI)、甲基三氟甲基磺酰亚胺锂、三氟甲基(五氟乙基)磺酰亚胺锂和双(五氟乙基)磺酰亚胺锂等中的一种或多种，
    优选地，所述含氟磺酰亚胺锂盐包含双氟磺酰亚胺锂、或所述含氟磺酰亚胺锂盐为双氟磺酰亚胺锂。
  6. 根据权利要求1至5中任一项所述的锂离子电池，其中，所述第一锂盐相对于所述电解液的质量百分比C I≥4.0wt％以上，优选地，C I≥5.0wt％，更优选地，C I≥5.5wt％。
  7. 根据权利要求1至6任一项所述的锂离子电池，其中，所述电解质锂盐包括第二锂盐，所述第二锂盐选自LiPF 6、LiBF 4、LiSbF 6、LiAsF 6、LiClO 4和LiB(C 2O 4)中的一种或多种。
  8. 根据权利要求1至6任一项所述的锂离子电池，其中，所述电解质锂盐包括第二锂盐，所述第二锂盐选自无机含氟锂盐，优选地，所述第二锂盐选自LiPF 6、LiBF 4、LiPO 2F 2和Li 3POF中的一种或多种的组合。
  9. 根据权利要求7或8所述的锂离子电池，其中，第一锂盐与第二锂盐的摩尔比在1:1～20:1范围内，更优选地，在1.2:1～10:1范围内，尤其优选地在6:4～9:1范围内。
  10. 根据权利要求1至9任一项所述的锂离子电池，其中，所述电解液中包括有机溶剂，所述有机溶剂选自碳酸二甲酯(DMC)、碳酸二乙酯(DEC)、碳酸二丙酯(DPC)、碳酸甲乙酯(EMC)、碳酸甲丙酯(MPC)、碳酸乙丙酯(EPC)、碳酸乙烯亚乙酯(VEC)、碳酸乙烯酯(EC)、碳酸丙烯酯(PC)、γ-丁内酯(GBL)、碳酸丁烯酯(BC)、氟代碳酸乙烯酯(FEC)、甲酸甲酯(MF)、甲酸乙酯、乙酸甲酯(MA)、乙酸乙酯(EA)、乙酸丙酯(PA)、丙酸甲酯(MP)、 丙酸乙酯(EP)、丙酸丙酯(PP)、丁酸甲酯(MB)、丁酸乙酯(EB)、环丁砜(SF)、二甲砜(MSM)、甲乙砜(EMS)、二乙砜(ESE)、四氢呋喃(THF)和亚硫酸亚丙酯等中的一种或多种的组合。
  11. 根据权利要求1至10任一项所述的锂离子电池，其中，所述有机溶剂中环状碳酸酯的含量不超过10wt％。
  12. 根据权利要求1至11任一项所述的锂离子电池，其中，所述电解液中还包括氟代碳酸乙烯酯、二氟磷酸锂、二氟草酸硼酸锂、二氟双草酸磷酸锂中的一种或多种的组合。
  13. 根据权利要求1至12任一项所述的锂离子电池，其中，所述负极活性物质层的孔隙率P A为10％～50％；和/或
    所述负极活性物质层的压实密度PD A为1.5g/cm 3～2.1g/cm 3；和/或
    所述负极活性物质包含人造石墨或天然石墨中的一种或多种的组合。
  14. 根据权利要求1至13任一项所述的锂离子电池，其中，所述负极活性物质还包括中间相微碳球(MCMB)、硬碳、软碳、硅、硅-碳复合物、SiO、Li-Sn合金、Li-Sn-O合金、Sn、SnO、SnO 2、尖晶石结构的钛酸锂Li 4Ti 5O 12、Li-Al合金及金属锂中的一种或多种的组合。
  15. 根据权利要求1至14任一项所述的锂离子电池，其中，所述锂离子电池的浮充物理电阻增加率ΔR≤60，
    ΔR＝(R2-R1)/R1    (2)
    其中，R1为所述锂离子电池1kHz下的物理电阻；R2为锂离子电池以1C恒流充电至额定电压，在所述额定电压下恒压充电至电流为0.1C，并在所述额定电压下恒压充电24h以后，所述锂离子电池的1kHz下的物理电阻。
  16. 一种电池模块，其包括根据权利要求1至15任一项所述的锂离子电池。
  17. 一种电池包，其包括根据权利要求16所述的电池模块。
  18. 一种装置，其包括根据权利要求1至15任一项所述的锂离子电池。
  19. 根据权利要求18所述的装置，其中，所述装置选自电动车辆、电动船舶、电动工具、电子设备及储能系统中的一种或多种。
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