WO2015154320A1 - 一种新型改性无纺布锂离子电池隔膜及其制备方法 - Google Patents

一种新型改性无纺布锂离子电池隔膜及其制备方法 Download PDF

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WO2015154320A1
WO2015154320A1 PCT/CN2014/076666 CN2014076666W WO2015154320A1 WO 2015154320 A1 WO2015154320 A1 WO 2015154320A1 CN 2014076666 W CN2014076666 W CN 2014076666W WO 2015154320 A1 WO2015154320 A1 WO 2015154320A1
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melting point
woven
modified non
filler
solvent
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PCT/CN2014/076666
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English (en)
French (fr)
Inventor
林妙云
黄美容
吴耀根
蔡朝辉
廖凯明
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佛山市金辉高科光电材料有限公司
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Priority to KR1020167027015A priority Critical patent/KR20160129868A/ko
Priority to JP2016561758A priority patent/JP6133520B2/ja
Publication of WO2015154320A1 publication Critical patent/WO2015154320A1/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
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/446—Composite material consisting of a mixture of organic and inorganic materials
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/44—Fibrous material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • 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
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/403—Manufacturing processes of separators, membranes or diaphragms
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H01M50/417—Polyolefins
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H01M50/426—Fluorocarbon polymers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • H01M50/429—Natural polymers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • H01M50/429—Natural polymers
    • H01M50/4295—Natural cotton, cellulose or wood
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/431—Inorganic material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/431—Inorganic material
    • H01M50/434—Ceramics
    • H01M50/437—Glass
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/443—Particulate material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • H01M50/491—Porosity
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the invention relates to a novel modified non-woven lithium ion battery separator, and to a preparation method of the battery separator.
  • Polyethylene and polypropylene separators currently in commercial use are more suitable for digital batteries such as mobile phones and cameras.
  • this type of diaphragm there are some shortcomings in this type of diaphragm: On the one hand, when the melting temperature of the polyolefin is lower than 165 °C, the battery may be melted when the external temperature is too high or accidentally hit, causing the battery to be short-circuited, resulting in battery burning. Explosion; On the other hand, the polyolefin electrolyte has poor ability to maintain electrolyte capacity, resulting in poor battery cycle life, high current charge and discharge performance. The lack of safety and electrical performance of such diaphragms limits their use in power storage batteries.
  • the patent CN102629679A provides a three-layer nanofiber lithium ion composite membrane, which has good thermal stability, high porosity, good liquid absorption capacity, and is improved by hot pressing composite. Mechanical strength.
  • the three-layer composite structure is formed by electrospinning, the peel strength of the separator is low, resulting in a large interfacial impedance, and the internal resistance of the battery is still large, which is not conducive to large current charging and discharging of the power storage battery, and The aperture is too large, the high-voltage insulation is poor during battery manufacturing, and the short-circuit rate in the battery is as high as 10%.
  • Patent CN1679185 provides a ceramic diaphragm suitable for high power lithium ion batteries.
  • the separator is coated with a ceramic coating on a substrate of the nonwoven fabric, and has oxide particles of elements of Al, Zr, Si and an inorganic material having an ion conductive function.
  • the biggest advantage of the separator is high ion conductivity, high melting point above 250 °C, good thermal stability and good electrochemical stability.
  • the prepared battery is excellent in high current charge and discharge performance.
  • the inorganic material of the diaphragm coating layer is exposed on the outer surface, and is easy to absorb water, thereby producing a suction of the diaphragm. The water is extremely high. It is difficult to remove the moisture by the ordinary baking process in the battery manufacturing process.
  • the water will react with the electrolyte, causing the battery to swell and the internal resistance is increased.
  • the battery electrochemical performance is deteriorated, such as large capacity loss of the battery, poor cycle life, and the like.
  • the brittle inorganic coating has poor adhesion to the flexible substrate, resulting in poor mechanical handling during processing of the battery, and the separator is prone to problems such as bending voids, cracks, and damage, resulting in short circuit of the battery. If the problem of battery bubbling is to be solved, a longer baking time or a higher temperature to remove water in the process of preparing the battery increases the possibility of damage and shedding of the brittle inorganic coating.
  • the strength of the diaphragm is poor, and the processing requirement of high-speed automatic winding cannot be satisfied, the puncture resistance of the pole piece is poor, and the short circuit rate is high.
  • the above diaphragms are optimized for different performances, but we can see from the above analysis that there is still much room for improvement. Because the power storage battery is required to be a high-capacity and high-power charge and discharge battery, it has high requirements on the diaphragm in terms of safety performance and electrical performance, so the diaphragm should have good thermal stability and electrochemical stability at the same time. High performance, high lithium ion conductivity, excellent liquid retention, low moisture content, and easy battery processing. Summary of the invention
  • the present invention provides a novel modified non-woven lithium ion battery separator, and the present invention.
  • the invention also provides a method of preparing the battery separator.
  • a novel modified non-woven lithium ion battery separator comprising a modified non-woven substrate and a composite filler thereof:
  • the filler is filled in the pores of the modified nonwoven fabric substrate, and at this time, the pores of the nonwoven fabric substrate are filled with a filler; preferably, the filler is from the pore of the modified nonwoven fabric substrate.
  • the thickness of the separator Extending the inside and outside to coat the entire modified non-woven fabric substrate, the thickness of the separator being 1-10 times the thickness of the modified non-woven fabric substrate, more preferably The thickness of the separator is 1-2 times the thickness of the modified nonwoven fabric substrate.
  • the structure of the modified non-woven lithium ion battery separator is a layer of non-woven fiber layer in the middle, and the nonwoven fabric is non-woven.
  • the pores of the cloth substrate are filled with a filler, and the surface of the nonwoven fabric substrate is also coated with a filler;
  • the modified non-woven substrate the pores having a pore size of 1-50000 nm are distributed on the substrate to ensure the thickness of the non-woven modified composite film and the uniformity of the pore structure; And the liquid surface tension and other factors, the substrate porosity is 30-95%, the porosity is more than 30%, the prepared membrane has better liquid absorption and liquid retention ability, ensuring the conduction of lithium ions in the diaphragm, making the system
  • the obtained battery has a small internal resistance, which is favorable for high-power charging and discharging of the battery, but the porosity is greater than 95%, which may result in insufficient strength of the non-woven substrate, and the obtained separator battery has poor processability and low yield.
  • the modified non-woven substrate comprises a low melting point material and a high melting point material, the low melting point material is subjected to melt crystallization treatment, and the high melting point material is 85-99.9% of the total weight of the modified non-woven substrate, and the rest is a low melting point material.
  • the high melting point material is a mixture of one or more of polyester, polyolefin, nitrile polymer, aromatic polyimide, and polyether having a melting point of 200 ° C, wherein the polyester includes but is not limited to Polyethylene terephthalate (PET), poly(p-phenylene terephthalate) (PPT), polybutylene terephthalate (PBT), poly(phthalic acid)
  • PET Polyethylene terephthalate
  • PPT poly(p-phenylene terephthalate)
  • PBT polybutylene terephthalate
  • Polyolefin fibers include, but are not limited to, poly(4-decylpentene) materials
  • celluloses include, but are not limited to, polyvinyl acetal-nanocrystalline cellulose, tencel materials
  • polynitrites include, but are not limited to, Polyacrylonitrile (PAN) materials
  • Polyimides include, but are not limited to, aromatic polyimide materials
  • the low melting point material is one or more of a polyolefin having a melting point of 50 to 199 ° C, a polyvinyl alcohol, a polystyrene, a thermally bonded polyester, and a fluorine-based polymer.
  • a substrate made of a low melting point material and a high melting point material is used, so that the substrate has a bimodal melting point.
  • the low melting point material having a small part by weight starts to soften and melt, and changes the original fiber shape. Appearance, reforming the surface to form a uniform structure, and the high-melting body material with a large weight The material did not change due to its high temperature stability.
  • the heat pressure is released, the previously melted low-melting melt gradually solidifies or recrystallizes, and the high-melting-point materials are tightly compounded together, thereby improving the strength and surface flatness of the entire substrate, and the tensile strength can reach 60 MPa.
  • the puncture strength can reach 3N.
  • the low melting point material comprises from 0.1 to 15% by weight of the substrate, and the high melting point material comprises from 85 to 99.9% by weight of the substrate.
  • the content of the low melting point material exceeds 15%, the poorer the high temperature heat shrinkage property of the obtained substrate, the more easily the separator shrinks at high temperature, resulting in short-circuit explosion of the positive and negative electrodes of the battery; the content of the low melting point material is less than 0.1%, and the prepared membrane surface The greater the roughness, the worse the thickness of the hook, and the worse the mechanical strength, the lower the pass resistance of the insulation breakdown short circuit test.
  • the preferred melt crystallization treatment refers to a process in which a low melting point material is heated to be melted at a temperature of 0 to 10 ° C above its melting point, and then cooled to cool it.
  • the melting temperature is 0-10 ° C above the melting point of the low melting point material, so that the low melting point material having a small weight fraction is softened and melted, and the original fiber morphology is changed, and the surface is evenly formed and the weight is re-formed.
  • the high-melting-point host material does not change due to its high-temperature stability.
  • the cooled crystallization of the melted low-melting melt closely bonds the high-melting substance together, thereby increasing the strength of the entire substrate.
  • the filler on the modified nonwoven fabric substrate comprises an organic polymer, a first filler material and/or a second filler material, wherein:
  • the organic polymer is one or a combination of two or more of a fluorine-based polymer, a rubber, an ester polymer, a cellulose, a starch, etc.
  • the fluorine-based polymer includes, but not limited to, polyvinylidene fluoride, poly Vinylidene fluoride-hexafluoropropylene, polytetrafluoroethylene, polyvinylidene fluoride-trichloroethylene
  • the rubber includes but not limited to styrene butadiene rubber, carboxylated styrene butadiene rubber, nitrile rubber, silicone rubber
  • Polymers include, but are not limited to, polydecyl methacrylate, polyethyl methacrylate, polybutyl methacrylate, poly glyceryl acrylate, polyethylene glycol acrylate, polyethylene vinyl acetate, polyvinyl acetate
  • the cellulose includes, but is not limited to, cellulose acetate,
  • the selected organic polymer has an electrolyte-clearing ability to ensure the liquid absorption and liquid retention of the separator, thereby ensuring the ionic conductivity of the separator and the cycle performance of the battery.
  • the organic polymer chosen should have suitable creep properties and wettability with the filler material to better agglomerate and encase the filler material.
  • the first filler material is an inorganic particle having a particle diameter of from 1 to 2000 nm, preferably from 10 to 1000 nm, further preferably from 50 to 500 nm.
  • the first filler material is an inorganic nanoparticle, which mainly functions to fill the pores of the non-woven fabric and improve the high temperature stability of the separator, including but not limited to one of inorganic oxide nanoparticles, inorganic nitride nanoparticles, ore nanoparticles. kind or several.
  • the inorganic oxide nanoparticles are at least one of silica, alumina, titania, zirconia, magnesia, magnesium hydroxide, cerium oxide, oxidized iron, iron oxide and cerium oxide;
  • the nitride nanoparticles are at least one of silicon nitride, titanium nitride and boron nitride;
  • the ore nanoparticles are calcium carbonate, calcium sulfate, aluminum hydroxide, potassium titanate, barium titanate, talc, kaolin At least one of clay, high cold stone, pyrophyllite, montmorillonite, mica, bentonite, calcium silicate, magnesium silicate, diatomaceous earth and silica sand.
  • the shape of the first filling material may be spherical, nearly spherical, dumbbell-shaped, rod-shaped, or the like.
  • the second filler is a fiber particle having a particle diameter of from 1 to 10000 nm, preferably having a particle diameter of from 100 to 5,000 nm, more preferably from 300 to 3,000 nm.
  • the second filler material is fiber particles, the fiber particles are wollastonite fiber, glass fiber, lignin, cellulose nanofiber, acrylic fiber, nylon fiber, polyester fiber, aramid One or a mixture of two or more of fibers, polyimide fibers, and the like.
  • the modified nonwoven fabric substrate material is one or a mixture of a polyester, a polyolefin, a cyanopolymer, and a polyimide.
  • the first filler material is an inorganic oxide particle.
  • the second filling material is one or a mixture of wollastonite fibers, lignin, cellulose.
  • a preparation method of a novel modified non-woven lithium ion battery separator comprising the following steps: a.
  • Making a non-woven fiber layer processing a high-melting material and a low-melting material into a non-woven fiber layer, and the processing may be melt-blown, spunbonding, paper making, hydroentanglement, needle punching, hot rolling One of them, wherein the weight of the high melting point material accounts for 85-99.9% of the total weight of the nonwoven fabric fiber layer, and the balance is a low melting point material; the above process can adjust the pore size and pores of the nonwoven fiber layer by adjusting parameters Rate is controlled.
  • the high melting point material is one or more of a polyester having a melting point of >200° (polyester, polyolefin, nitrile polymer, aromatic polyimide, polyether);
  • the low melting point material is a polyolefin having a melting point of 50-199 ° C, a polyvinyl alcohol, a polystyrene, a heat-bonding polyester, a fluorine-based polymer;
  • melt crystallization treatment means that the low melting point material is above the melting point of the low melting point material used in the step a- It is heated by heating at a temperature of 10 ° C, and then cooled to cool the crystallization process.
  • the melting temperature is 0-10 ° C above the melting point of the low melting point material used in the step a, so that the low melting point material having a small part by weight is softened and melted, and the original fiber morphology is changed, and the surface is uniformly formed into a uniform structure.
  • the high-melting-point host material having a large weight does not change due to its high-temperature stability.
  • the cooling crystallization of the melted low-melting melt closely bonds the high-melting substance together, thereby raising the entire base.
  • the strength of the material is further dried to ensure that the moisture content of the nonwoven fabric is as low as possible.
  • Preparation of filler slurry The first filler material and the second filler material are dried. Mixing the organic polymer, the first solvent and the second solvent in a weight ratio of 1: (5 ⁇ 50): (0.1 ⁇ 10), stirring and heating to dissolve, adding the dried first filling material and/or the first Two filling materials, evenly mixed;
  • the organic polymer is a fluorine-based polymer, a rubber, an ester polymer, cellulose, starch, or the like.
  • the fluorine-based polymer includes, but not limited to, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polytetrafluoroethylene, polyvinylidene fluoride-trichloroethylene
  • the rubber includes but is not limited to styrene-butadiene rubber, carboxylated styrene butadiene rubber, nitrile rubber, silicone rubber
  • the ester polymer includes, but is not limited to, polydecyl methacrylate, polyethyl methacrylate, polydecyl acrylate Ester, polyglyceryl acrylate, polyethylene glycol acrylate, polyethylene-vinyl acetate, polyvinyl acetate
  • the cellulose includes, but is not limited to, cellulose a
  • the first solvent is one or a mixture of two or more of a ketone solvent, an amide solvent, and an ester solvent; wherein the ketone solvent includes, but is not limited to, acetone, butanone, and N-mercaptopyrrolidone; the amide solvent includes Not limited to NN dimercaptoacetamide, NN dimercaptoamide; ester solvents include, but are not limited to, triethyl phosphate, tridecyl phosphate, and ethyl acetate.
  • the second solvent is one or a mixture of two or more of water, an alcohol solvent, and a surface hydrocarbon solvent; the second solvent is water, an alcohol solvent, one or a mixture of two or more hydrocarbon solvents;
  • the alcohol solvent includes, but is not limited to, decyl alcohol, ethanol, propanol, isopropanol, isobutanol, ethylene glycol, n-butanol, glycerin;
  • the surface hydrocarbon solvent includes, but is not limited to, trichloromethane, Dichlorodecane.
  • the second solvent selected has a boiling point higher than the boiling point of the first solvent by more than 10 °C.
  • the agitation heating temperature should be below the boiling point of the first solvent, preferably below the boiling point of the first solvent by 10 °C or less. If the heating temperature is too high, the solvent volatilizes too quickly, causing the slurry to easily cause agglomeration due to excessive local temperature.
  • step d filling the non-woven fabric: the filler slurry prepared in step c is filled on the modified non-woven fabric substrate obtained in step b;
  • Removing the solvent removing the solvent from the non-woven fabric layer subjected to the d-step processing by extraction, drying, etc., to obtain a preliminary non-woven lithium ion battery separator;
  • step f. post-treatment heating the preliminary non-woven lithium ion battery separator prepared in step e to the The melting point of organic polymer is above 5-30 °C;
  • a third solvent which is one or a mixture of two or more of water, a ketone solvent, an amide solvent, an ester solvent, an alcohol solvent, and a hydrocarbon solvent.
  • the organic polymer will further tightly enclose the filler material and make the membrane moisture less and stronger. Although the organic polymer may creep during this process and the coating pore structure changes, the pore structure of the coating void does not change, so that the separator does not undergo large heat shrinkage. Moreover, the inorganic particles are surrounded by the organic polymer, and most of the inorganic particles are isolated from the air, which greatly reduces the water absorption of the inorganic particles. After the treated membrane was placed in air at normal temperature and humidity for several months, it still maintained a low water content.
  • the third solvent may be the same as or different from the first solvent, and is preferably acetone, water or N-N decyl sulfoxide.
  • the organic polymer may be dissolved to change the pore structure of the coating, but it should not affect the excellent properties of the separator.
  • a corresponding auxiliary agent may contribute to the film formation, but may not cause any adverse effects on the battery system.
  • the adjuvant may include, but is not limited to, one or more of a dispersing agent, an antifoaming agent, a surfactant, and the like.
  • the dispersing agent may be a commercially available dispersing agent such as one or more of polyvinylpyrrolidone (PVP), sodium carboxymethylcellulose, sodium polyacrylate, and the like.
  • PVP polyvinylpyrrolidone
  • the dispersing agent may be a commercially available dispersing agent such as one or more of polyvinylpyrrolidone (PVP), sodium carboxymethylcellulose, sodium polyacrylate, and the like.
  • the surfactant is commercially available, for example, one or more of a fluorosurfactant, a silicon-containing surfactant, a polyether surfactant, and the like.
  • the antifoaming agent is commercially available, for example, one or more of natural fats, silicone antifoaming agents, high carbon alcohols, polyether antifoaming agents, and the like.
  • the weight ratio of the total weight of the first filler material and the second filler material to the organic polymer is (1:5) - (5:1); the second filler material accounts for a filling material and a second The ratio of the total weight of the filler material is 0-50%.
  • the prepared lithium electronic battery separator may be added or compounded with additional mechanical treatment, such as hot calendering, centrifugation, stretching treatment, etc., as needed. . If you want to increase the porosity, you can consider increasing the stretching process. If you want to reduce the porosity, you can consider increasing the rolling or centrifuging.
  • the invention provides a novel lithium ion battery separator, which can achieve the following technical effects:
  • the unique non-woven substrate can greatly improve the strength of the diaphragm, ensure the battery winding processability, and improve the battery yield.
  • the special organic polymer coated inorganic particle structure can greatly reduce the water absorption of the battery separator, reduce the possibility of moisture entering the battery system, and avoid the battery blow and internal resistance caused by excessive moisture and electrolyte reaction. It becomes larger, thereby improving the rate discharge performance and service life of the battery.
  • the invention also provides a preparation method of a novel lithium ion battery separator, which has the advantages of simple operation, low cost, low moisture content, good chemical stability and high mechanical strength, and improves the yield and service life of the battery. And security.
  • Fig. 1 is a schematic view showing the structure of a modified non-woven lithium ion battery separator of Example 1.
  • Modified non-woven substrate 2. Filler.
  • Example 1 95 g of high melting point PET fiber having a melting point of 250 ° C, 5 g of a low melting point PET fiber having a melting point of 150 ° C were copied into a nonwoven fabric web layer by a wet paper making method, and the nonwoven fabric web layer was melted. Crystallization treatment, the temperature was 155 ° C, and then cooled to obtain a modified non-woven fabric having a porosity of 58%, an average pore diameter of llum, a puncture strength of 3.0 N, a heat shrinkage of 150 ° C lh of 1%, and a thickness of 16 ⁇ m.
  • Substrate 1 Taking filler 2, the filler includes aluminum oxide, PVDF;
  • the melt-crystallized nonwoven fabric was dried, and the drying temperature was 90 ° C for 1 min.
  • 40 g of aluminum oxide having a particle diameter of 250 nm was placed in an oven at a temperature of 100 ° C. The time is 4h.
  • the modified non-woven fabric lithium ion battery separator comprises a modified non-woven fabric substrate 1 and a filler 2, wherein the filler 2 is filled in the pores of the modified non-woven fabric substrate 1 and extends outward. The entire modified nonwoven fabric substrate 1 is coated.
  • a modified non-woven lithium ion battery separator was prepared according to the method of Example 1, except that 0.5 g of low melting point PET fiber having a melting point of 150 ° C was added to obtain a puncture strength of 2.2 N, 150 ° C lh heat shrinkage. It is a 0.5% nonwoven substrate.
  • a modified non-woven lithium ion battery separator was prepared according to the method of Example 1, except that 16.8 g of a low melting point PET fiber having a melting point of 150 ° C was added to obtain a puncture strength of 3.2 N, and a heat shrinkage of 150 ° C lh was obtained. 5% non-woven substrate.
  • a modified non-woven lithium ion battery separator was prepared according to the method of Example 1, except that the filling was performed.
  • the thickness of the back diaphragm is the same as that of the non-woven substrate before filling, which is 16um.
  • a modified non-woven lithium ion battery separator was prepared in accordance with the method of Example 1, except that a modified nonwoven fabric substrate was produced by a meltblown process.
  • a modified non-woven lithium ion battery separator was prepared in the same manner as in Example 1 except that 40 g of aluminum oxide having a particle diameter of 250 nm was placed in an oven at a temperature of 80 ° C for a period of 1 min.
  • a modified non-woven lithium ion battery separator was prepared in the same manner as in Example 1 except that 20 g of wollastonite fiber particles having a particle diameter of 1200 nm were added.
  • a modified non-woven lithium ion battery separator was prepared in the same manner as in Example 1, except that the organic polymer was selected from PVDF-HFP having a melting point of 145 ° C, and the first solvent was selected from methyl ethyl ketone.
  • a modified non-woven lithium ion battery separator was prepared in the same manner as in Example 1 except that the first filler was made of magnesium hydroxide having a particle diameter of 800 nm.
  • a modified non-woven lithium ion battery separator was prepared according to the method of Example 1, except that the preliminary non-woven composite membrane was immersed in water (1 - 5 ) min, and then dried to obtain the present invention. Modified non-woven lithium ion battery separator.
  • a modified non-woven lithium ion battery separator was prepared according to the method of Example 1, except that the initial The step non-woven composite membrane was hot pressed at a temperature of 180 °C.
  • a lithium ion battery separator was prepared in accordance with the method of Example 1, except that a modified nonwoven fabric substrate was prepared without adding a 150 ° C low melting point PET material.
  • a lithium ion battery separator was prepared in accordance with the method of Example 1, except that 24 g of a low melting point PET material having a melting point of 150 ° C was added to prepare a modified nonwoven fabric substrate.
  • a lithium ion battery separator was prepared in the same manner as in Example 1 except that the nonwoven fabric substrate and the aluminum oxide were not dried.
  • a lithium ion battery separator was prepared in the same manner as in Example 1 except that it did not undergo any post-treatment process.
  • a lithium ion battery composite separator was prepared in accordance with the method of Example 1, except that the substrate was coated with a single layer PE film.
  • the positive electrode is made of lithium cobalt oxide LiCo02
  • the negative electrode is made of graphite
  • the electrolyte of the battery is made of ethylene carbonate.
  • Ester (EC): Diethyl carbonate (DEC): Dimethyl carbonate (DMC) volume ratio 1:1:1 solution, electrolyte added solute is 1 mol/L lithium hexafluoroacetate LiPF6, respectively
  • the separators of Examples 1-6 and Comparative Examples 1-5 were used for battery performance evaluation.
  • Example 1 2.0 1.0 3.1 58 Example 2 1.0 0.5 2.3 40 Example 3 6.0 5.0 3.3 70 Example 4 1.5 0.8 3.0 65 Example 5 2.8 1.0 2.8 65 Example 6 2.2 1.2 3.1 57 Example 7 2.0 1.0 3.4 57 Implementation Example 8 3.0 2.0 2.9 56 Example 9 2.2 1.2 3.2 58 Example 10 2.0 1.0 3.2 60 Example 11 2.2 1.1 3.5 70 Comparative Example 1 1.8 0.8 1.0 30 Comparative Example 2 10.0 8.2 3.4 68 Comparative Example 3 2.0 1.2 3.0 57 Comparative Example 4 2.2 1.2 2.2 38 Comparative Example 5 8.0 4.2 3.5 90 Comparative Example 6 9.5 5.4 3.2 88 Comparative Example 7 3.0 2.0 0.8 28 The test results from Table 1 show that the separator of the present invention has a lower ratio than the ordinary ceramic separator.
  • the separator prepared by the specific high and low melting point characteristics of the non-woven fabric substrate of the present invention has sufficient puncture tensile strength while ensuring low heat shrinkage performance. , to ensure the processing rate and safety of the diaphragm battery. Water content test results after different baking times
  • Comparative example 1 485 315 198 160 Comparative Example 2 498 332 210 169 Comparative Example 3 1592 1125 802 565
  • Comparative Example 7 642 428 306 255 The test results from Table 2 show that the separator of the present invention has a lower water content than a conventional ceramic separator. Compared with Comparative Examples 3, 4, and 6, the separator composed of the substrate and the filling structure of the present invention has a low water content and requires less processing due to the particularity of processing and the structure of the organic polymer-coated inorganic particles. Baking time.
  • each of the examples prepared 100 batteries. During the preparation of the battery, the cells were baked in a vacuum oven at 85 ° C for 24 hours, and then the battery was subjected to an insulation breakdown short circuit test, and batteries tested for different voltages. Statistics are performed by the number. The test results are shown in Table 3.
  • Comparative Example 5 100 100 Comparative Example 6 100 100 Comparative Example 7 50 5
  • the test results from Table 3 show that the separator of the present invention has better insulation resistance than the conventional non-woven membrane separator, and the pass rate of the 250V breakdown short test is up to 100%, while the ordinary nonwoven membrane pass rate is 5%.
  • the separator composed of the substrate and the filler structure of the present invention has a large insulation resistance and a high battery yield due to the specificity of the substrate and the coating structure of the coating. .
  • Acupuncture At room temperature, when charging at a constant current of 0.5C to a charge limit voltage of 4.2V, turn off the constant voltage charging 3.5 ⁇ or the current is reduced to 0.02C, the charging is cut off, and the battery after charging is 3.0 ⁇ 8.0mm in diameter. of Iron nails, piercing the battery vertically at a speed of 21-40mm/sec, the standard is no fire, no explosion.
  • Short circuit Tested according to the national standard GB/T18287-2013 method, the standard is judged to be non-flammable, non-explosive, and the outer surface temperature is lower than 150 °C.
  • Overcharge According to the national standard GB/T18287-2013 method to test, the standard is no fire, no explosion. The test results are shown in Table 4.
  • the test results show that the battery prepared by the separator of the present invention is superior in safety performance test,
  • Rate discharge Test according to the national standard GB/T18287-2013 method.
  • Cyclic performance using the equipment BS-9300 performance tester, 1C rate charge and discharge cycle test, using constant current constant voltage charging system (CC-CV) and constant current discharge system, charging and discharging voltage range 3.0 ⁇ 4.2 V, First, it is charged to 4.2 V with a constant current of 1 C, and then charged to a current of less than 20 mA at a constant voltage of 4.2 V, and then discharged at a constant current of 1 C to a final voltage of 3.0 V, and thus cycled 500 times to collect the cycle data.
  • CC-CV constant current constant voltage charging system
  • Example 1 99.5 95.0 90.0 83.0 75.0 98.5 99.5 4 87.0 17.0
  • Example 2 99.6 96.5 90.8 83.2 76.2 98.8 99.6 4 87.5 16.8
  • Example 3 99.0 94.5 89.0 81.5 74.0 98.0 99.0 4 86.0 17.5
  • Example 4 99.5 95.5 91.0 85.0 77.5 97.0 98.5 5 86.5 16.5
  • Example 5 99.2 95.8 90.5 84.0 76.0 97.5 98.8 4 86.8 16.8
  • Example 6 99.0 94.2 88.5 81.0 73.0 96.0 97.5 6 85.0 18.0
  • Example 8 99.0 96.0 92.5 85.0 78.0 97.0 98.5 4 86.0 16.8
  • Example 98.0 93.0 87.5 80.2 72.0 96.5 98.0 5 84.5 18.0
  • Example 10 98.5 94.5 88.5 81.0 74.5 97.0 98.0 5 85.5 17.5
  • the substrate and the filler of the invention impart the thickness and pore size of the separator, good electrochemical stability, excellent liquid retention and liquid absorption, and extremely low water absorption, so that the battery prepared by the separator of the invention has excellent performance. Rate of discharge performance and cycle life.
  • the above embodiments are merely preferred embodiments of the present invention, and the scope of the present invention is not limited thereto, and any insubstantial changes and substitutions made by those skilled in the art based on the present invention belong to the present invention. The scope of the claim.

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Abstract

一种改性无纺布锂离子电池隔膜，所述隔膜包括改性无纺布基材（1）及其复合的填充剂（2），所述改性无纺布基材（1）包括低熔点材料和高熔点材料，所述低熔点材料经过熔融结晶处理，高熔点材料的重量为基材总重的85-99.9%，余量为低熔点材料；所述改性无纺布基材（1）上复合的填充剂（2），包括有机聚合物，以及第一填充材料和/或第二填充材料。该电池隔膜制备方法，依次包括如下步骤：制作无纺布纤维层，制作改性无纺布基材（1）；制备填充剂（2）浆料；填充；去除溶剂；后处理。该方法操作简单、成本低，制备出的产品水分含量低、化学稳定性好、机械强度高，提升了电池的成品率、使用寿命和安全性。

Description

一种新型改性无纺布锂离子电池隔膜及其制备方法 技术领域
本发明涉及一种新型改性无纺布锂离子电池隔膜， 同时还涉及该电池隔膜 的制备方法。
背景技术
目前商业化应用的聚乙烯、聚丙烯隔膜比较适用于手机、相机等数码类电池。 但该类隔膜存在某些不足： 一方面， 由于聚烯烃熔融温度低于 165 °C , 电池在外 部温度过高或者受到意外撞击的时候， 隔膜可能被熔破， 导致电池短路， 从而 导致电池燃烧爆炸； 另一方面， 聚烯烃亲电解液能力差， 保持电解液能力不足， 导致电池循环寿命、 大电流充放电等性能差。 此类隔膜在安全性能和电性能方 面的不足， 限制了其在动力储能电池的使用。
为了改善隔膜安全性能和吸液保液能力，专利 CN102629679A提供了一种三 层纳米纤维锂离子复合隔膜， 该隔膜热稳定性好、 孔隙率高， 吸液能力佳， 并 通过热压复合改善其机械强度。 但由于是通过静电纺丝喷涂形成三层复合结构， 该隔膜的剥离强度低， 导致其界面阻抗大， 制得的电池内阻仍然偏大， 不利于 动力储能电池大电流充放电， 且其孔径偏大， 电池制作过程中耐高压绝缘性差， 电池内短路率高达 10%。
专利 CN1679185提供了一种适用于高功率锂离子电池的陶瓷隔膜。 该隔膜 在无纺布的基体上涂覆陶瓷涂层， 具有元素为 Al、 Zr、 Si的氧化物颗粒以及具 备离子导电功能的无机材料。 该隔膜的最大优点是离子电导率高、 熔点高于 250 °C , 热稳定性好、 电化学稳定性好， 所制备的电池在大电流充放电性能上表 现优异。 但该隔膜涂覆层的无机材料棵露在外表面， 容易吸水， 制得隔膜的吸 水性极高， 电池制作过程中的普通烘烤工艺很难将该水分除干净， 一旦将较多 的隔膜水分带到电池体系， 水分会与电解液反应， 导致电池鼓气， 内阻增大， 使得电池电化学性能变差， 如电池的容量损失大、 循环寿命差等。 另外， 其脆 性的无机涂层对柔性基材的附着力差， 导致其在加工电池过程中的机械操作性 差， 隔膜容易出现弯折空隙、 裂缝和损坏等问题， 从而导致电池短路。 如要解 决电池发鼓问题， 在制备成电池的过程中需要更长的烘烤时间或者更高的温度 除水， 则增加其脆性无机涂层损坏和脱落的可能性。 且该隔膜强度较差， 无法 满足高速自动卷绕的加工要求， 耐极片粉尘刺穿能力较差， 短路率偏高。
上述隔膜在不同的性能上进行了优化， 但我们从上述分析可以发现其中仍 有较大的改善空间。 因为动力储能电池均要求是高容量和大功率充放电的电池， 其在安全性能和电性能方面对隔膜提出了很高的要求， 因此隔膜应该要同时具 备良好的热稳定性和电化学稳定性、 高的锂离子传导性、 优异的吸液保液能力、 水分含量低、 易于电池加工等性能。 发明内容
为了解决现有锂离子电池隔膜易吸水、 耐热性差、 强度不高等问题， 从而 改善锂离子电池使用寿命和安全性， 本发明提供了一种新型改性无纺布锂离子 电池隔膜， 同时本发明还提供该电池隔膜的一种制备方法。
为解决上述问题， 本发明所釆用的技术方案如下：
一种新型改性无纺布锂离子电池隔膜， 所述隔膜包括改性无纺布基材及其 复合的填充剂：
所述填充剂填充在在改性无纺布基材的孔内， 此时无纺布基材的孔隙内填 充了填充剂； 优选的是所述填充剂从改性无纺布基材的孔内往外延伸将整个改 性无纺布基材包覆， 所述隔膜的厚度为改性无纺布基材厚度的 1-10倍， 更优选的 是所述隔膜的厚度为改性无纺布基材厚度的 1-2倍， 此时， 所述改性无纺布锂离 子电池隔膜的结构为中间是一层无纺布纤维层， 无纺布基材的孔隙内填充了填 充剂， 并且无纺布基材的表面也被填充剂所包覆；
所述改性无纺布基材： 基材上分布有均勾的孔径大小为 l-50000nm的孔， 确 保无纺布改性复合膜的厚度及孔径结构的均勾性； 基于毛细管吸液原理和液体 表面张力等因素， 基材孔隙率为 30-95%, 孔隙率超过 30%, 制得的隔膜具有更 好的吸液保液能力， 保证了锂离子在隔膜中传导通畅， 使得所制得的电池内阻 小， 有利于电池大功率充放电， 但孔隙率大于 95%, 会导致无纺布基材的强度不 足， 制得的隔膜电池加工性差， 成品率低。
改性无纺布基材包括低熔点材料和高熔点材料， 所述低熔点材料经过熔融 结晶处理，高熔点材料为改性无纺布基材总重量的 85-99.9%,其余为低熔点材料； 所述高熔点材料为熔点为 200 °C的聚酯、聚烯烃、腈聚合物、 芳香族聚酰亚胺、 聚醚中的一种或多种混合制成， 其中聚酯包括但不限于聚对苯二曱酸乙二醇酯 ( PET ), 聚对苯二曱酸丙二醇酯（PPT )、 聚对苯二曱酸丁二醇酯（PBT )、 聚邻 苯二曱酸亚乙酯材料； 聚烯烃类纤维包括但不限于聚（4-曱基戊烯）材料； 纤维 素类包括但不限于聚乙烯醇缩曱醛 -纳米晶体纤维素、 天丝材料； 聚腈类包括但 不限于聚丙烯腈 （PAN )材料； 聚酰亚胺类包括但不限于芳香族聚酰亚胺材料； 聚醚类包括但不限于聚醚醚酮、 聚醚砜、 聚苯醚、 聚苯硫醚材料。 所述低熔点 材料为熔点为 50-199 °C的聚烯烃、 聚乙烯醇、 聚苯乙烯、 热粘合聚酯、 氟类聚合 物中的一种或多种。
选用具有低熔点材料和高熔点材料制得的基材， 使得基材具有双峰熔点， 在一定的热量与机械压力下时， 重量份少的低熔点材料开始软化熔融， 并改变 原先的纤维形貌， 重新形成表面平整均匀的结构， 而重量份多的高熔点主体材 料因其高温稳定性而没有变化。 当热量压力释放后， 之前融化的低熔点熔融物 逐渐冷却固化或重结晶， 将高熔点材料紧密地复合在一起， 提升了整个基材的 强度与表面平整度， 其拉伸强度可达 60MPa, 穿刺强度可达到 3N。 低熔点材料 占基材重量的 0.1-15%, 高熔点材料占基材重量的 85-99.9%。 低熔点材料含量超 过 15%, 制得的基材高温热收缩性能越差， 隔膜在高温下越容易收缩从而导致电 池正负极接触短路爆炸； 低熔点材料含量低于 0.1%, 制得的隔膜表面粗糙度越 大， 厚度均勾性越差， 同时其机械强度越差， 耐绝缘性击穿短路测试通过率越 低。
本发明中，优选的熔融结晶处理是指将低熔点材料在其熔点之上 0-10 °C的温 度下加热使其熔融， 然后降温使其冷却结晶的过程。 所述熔融的温度为使用低 熔点材料的熔点之上 0-10°C ,使得重量份少的低熔点材料软化熔融， 并改变原先 的纤维形貌， 重新形成表面平整均匀的结构， 而重量份多的高熔点主体材料因 其高温稳定性而没有变化， 当停止加热、 温度降低时， 融化的低熔点熔融物的 冷却结晶将高熔点物质紧密地复合在一起， 提升了整个基材的强度。
所述改性无纺布基材上的填充剂， 包括有机聚合物， 第一填充材料和 /或第 二填充材料， 其中：
所述有机聚合物为氟类聚合物、 橡胶、 酯类聚合物、 纤维素、 淀粉等中的 一种或者两种以上的组合， 所述氟类聚合物包括但不限于聚偏氟乙烯、 聚偏氟 乙烯 -六氟丙烯、 聚四氟乙烯、 聚偏二氟乙烯 -三氯乙烯； 所述橡胶包括但不限于 丁苯橡胶、 羧基丁苯橡胶、 丁腈橡胶、 硅橡胶； 所述酯类聚合物包括但不限于 聚曱基丙烯酸曱酯、 聚曱基丙烯酸乙酯、 聚曱基丙烯酸丁酯、 聚丙烯酸甘油酯、 聚丙烯酸乙二醇酯、 聚乙烯-乙酸乙烯酯、 聚乙酸乙烯酯； 所述纤维素包括但不 限于乙酸纤维素、 乙酸丁酸纤维素、 乙酸丙酸纤维素、 氰乙基纤维素、 羧曱基 纤维素及其混合物； 所述淀粉包括但不限于氰乙基支链淀粉、 支链淀粉等。 所选用的有机聚合物具备亲电解液能力， 以确保隔膜的吸液保液能力， 从 而保证隔膜的离子电导率和电池的循环性能。 所选用的有机聚合物应具备合适 的蠕变能力以及与填充材料的润湿性， 以便更好地团聚和包裹住填充材料。
所述第一填充材料， 其为粒径 l-2000nm的无机颗粒， 优选为 10-1000nm, 进 一步优选为 50-500nm。 所述第一填充材料为无机纳米颗粒， 主要起到填充无纺 布孔隙、 提高隔膜高温稳定性作用， 包括但不限于为无机氧化物纳米颗粒、 无 机氮化物纳米颗粒、 矿石纳米颗粒中的一种或几种。 所述的无机氧化物纳米颗 粒为二氧化硅、 氧化铝、 二氧化钛、 氧化锆、 氧化镁、 氢氧化镁、 氧化钇、 氧 化辞、 氧化铁和二氧化铈中的至少一种； 所述的无机氮化物纳米颗粒为氮化硅、 氮化钛和氮化硼中的至少一种； 所述的矿石纳米颗粒为碳酸钙、 硫酸钙、 氢氧 化铝、 钛酸钾、 钛酸钡、 滑石、 高岭土粘土、 高冷石、 叶腊石、 蒙脱石、 云母、 膨润土、 硅酸钙、 硅酸镁、 硅藻土和硅砂中的至少一种。 所述第一填充材料的 形状可以为球形、 近球形、 哑铃型、 棒状型等。
所述第二填充材料， 其为粒径 l-10000nm的纤维颗粒， 优选粒径为 100-5000nm, 进一步优选为 300-3000nm。 在隔膜中起到增强作用， 所述第二填 充材料为纤维颗粒， 所述纤维颗粒为硅灰石纤维、 玻璃纤维、 木质素、 纤维素 纳米纤维、 腈纶纤维、 锦纶纤维、 涤纶纤维、 芳纶纤维、 聚酰亚胺纤维等中的 一种或者两种以上的混合。
优选的是， 所述改性无纺布基材材料为聚酯、 聚烯烃、 氰聚合物和聚酰亚 胺中的一种或者几种混合。 所述第一填充材料为无机氧化物颗粒。 所述第二填 充材料为硅灰石纤维、 木质素、 纤维素中的一种或者几种混合。
一种新型改性无纺布锂离子电池隔膜的制备方法， 包括如下步骤： a. 制作无纺布纤维层：将高熔点材料和低熔点材料加工制成无纺布纤维层， 所述加工工艺可为熔喷、 纺粘法、 造纸、 水刺、 针刺、 热轧法中的一种， 其中 高熔点材料重量占制成无纺布纤维层总重量的 85-99.9%, 余量为低熔点材料； 上述工艺通过调整参数能够对无纺布纤维层的孔隙大小和孔隙率进行控制。
所述高熔点材料为熔点> 200°( 的聚酯、 聚烯烃、 腈聚合物、 芳香族聚酰亚 胺、 聚醚中的一种或多种；
所述低熔点材料为熔点为 50-199 °C的聚烯烃、 聚乙烯醇、 聚苯乙烯、 热粘 合聚酯、 氟类聚合物；
b. 制作改性无纺布基材：
制作改性无纺布基材： 将步骤 a所得的无纺布纤维层进行熔融结晶处理； 所述熔融结晶处理是指将低熔点材料在步骤 a 中所使用低熔点材料的熔点之上 0-10°C的温度下加热使其熔融， 然后降温使其冷却结晶的过程。 所述熔融的温度 为步骤 a中所使用低熔点材料的熔点之上 0-10 °C , 使得重量份少的低熔点材料 软化熔融， 并改变原先的纤维形貌， 重新形成表面平整均匀的结构， 而重量份 多的高熔点主体材料因其高温稳定性而没有变化， 当停止加热、 温度降低时， 融化的低熔点熔融物的冷却结晶将高熔点物质紧密地复合在一起， 提升了整个 基材的强度。 再将熔融结晶处理过的无纺布进行干燥， 确保无纺布水分含量尽 量低。
c 制备填充剂浆料： 对第一填充材料、 第二填充材料进行烘干处理。 将有 机聚合物、 第一溶剂和第二溶剂按照重量比为 1 : ( 5 ~ 50 )： ( 0.1 ~ 10 ) 混合， 搅拌加热溶解至澄清， 添加烘干过的第一填充材料和 /或第二填充材料， 混合均 匀；
所述有机聚合物为氟类聚合物、 橡胶、 酯类聚合物、 纤维素、 淀粉等中的 一种或者两种以上的组合； 所述氟类聚合物包括但不限于聚偏氟乙烯、 聚偏氟 乙烯 -六氟丙烯、 聚四氟乙烯、 聚偏二氟乙烯 -三氯乙烯； 所述橡胶包括但不限于 丁苯橡胶、 羧基丁苯橡胶、 丁腈橡胶、 硅橡胶； 所述酯类聚合物包括但不限于 聚曱基丙烯酸曱酯、 聚曱基丙烯酸乙酯、 聚曱基丙烯酸丁酯、 聚丙烯酸甘油酯、 聚丙烯酸乙二醇酯、 聚乙烯-乙酸乙烯酯、 聚乙酸乙烯酯； 所述纤维素包括但不 限于乙酸纤维素、 乙酸丁酸纤维素、 乙酸丙酸纤维素、 氰乙基纤维素、 羧曱基 纤维素及其混合物； 所述淀粉包括但不限于氰乙基支链淀粉、 支链淀粉等。
所述第一溶剂为酮类溶剂、 酰胺类溶剂和酯类溶剂的一种或者两种以上混 合； 其中酮类溶剂包括但不限于丙酮、 丁酮和 N-曱基吡咯烷酮； 酰胺类溶剂包 括但不限于 N-N二曱基乙酰胺、 N-N二曱基曱酰胺； 酯类溶剂包括但不限于磷 酸三乙酯、 磷酸三曱酯和乙酸乙酯。
所述第二溶剂为水、 醇溶剂、 面代烃溶剂中的一种或者两种以上混合； 第 二溶剂为水、 醇溶剂、 [¾代烃溶剂中的一种或者两种以上混合； 所述醇溶剂包 括但不限于曱醇、 乙醇、 丙醇、 异丙醇、 异丁醇、 乙二醇、 正丁醇、 丙三醇； 所述面代烃溶剂包括但不限于三氯曱烷、 二氯曱烷。
所选用的第二溶剂沸点较第一溶剂沸点高 10°C以上。 其中搅拌加热温度应 在第一溶剂的沸点以下， 优选低于第一溶剂沸点 10°C以下。 所述加热温度如果 过高， 则溶剂挥发过快， 导致浆料容易因为局部温度过高而导致结块现象。
d. 填充无纺布： 将 c步骤制得的填充剂浆料在经 b步骤制得的改性无纺布 基材上进行填充；
e. 去除溶剂： 将经过 d步骤加工的无纺布纤维层釆用萃取、 烘干等方式除 去溶剂， 得到初步的无纺布锂离子电池隔膜；
f. 后处理： 将经过 e步骤制得的初步的无纺布锂离子电池隔膜加热至所述 有机聚合物熔点以上 5-30 °C ;
或者浸浴在第三溶剂中， 所述第三溶剂为水、 酮类溶剂、 酰胺类溶剂、 酯 类溶剂、 醇溶剂和 [¾代烃溶剂中的一种或者两种以上混合。
经过 f步骤的处理，有机聚合物会进一步紧密地包裹住填充材料， 并使隔膜 水分含量更少， 强度更高。 虽然在该过程中有机聚合物可能发生蠕变， 涂层孔 隙结构发生变化， 但涂层空隙的微孔结构并不会变化， 使得隔膜不会发生大的 热收缩。 且无机粒子被有机聚合物包裹住， 无机粒子大部分表面都与空气隔绝， 极大地减少无机粒子的吸水性。 处理后的隔膜放置在常温常湿的空气中几个月 后， 依然保持低的含水量。
所述第三溶剂可以与第一溶剂相同， 也可以不同， 优选丙酮、 水、 N-N二 曱基亚砜。 在这种溶剂浴下， 有机聚合物可能出现溶解， 从而改变涂层孔隙结 构， 但不应影响隔膜的优异性能。
为了更好的提升涂层浆料的性能， 优选在 c 步骤中根据需要加入相应的助 剂， 所添加的助剂对成膜有一定的帮助， 但不应对电池体系造成任何不良影响。 所述助剂可以包括但不限于分散剂、 消泡剂、 表面活性剂等的一种或者多种。
所述分散剂可为市售分散剂， 如聚乙烯吡咯烷酮（PVP )、羧曱基纤维素钠、 聚丙烯酸钠盐等的一种或者多种。
所述表面活性剂市售可得， 如含氟表面活性剂、 含硅表面活性剂、 聚醚类 表面活性剂等的一种或者多种。
所述消泡剂市售可得， 如天然油脂、 硅类消泡剂、 高碳醇、 聚醚类消泡剂 等的一种或者多种。
进一步的是， 所述 c 步骤中： 所述第一填充材料、 第二填充材料的总重量 与有机聚合物的重量比为 （1 :5 ) - ( 5:1 ); 第二填充材料占第一填充材料和第二 填充材料的总重量的比例为 0-50%。
为了进一步提升该制得的电池隔膜的性能，在 f步骤后可根据需要对制得的 锂电子电池隔膜增加或者复合额外的机械处理， 如热压延、 离心、 拉伸处理等 一种或者多种。 如需增加孔隙率， 可考虑增加拉伸处理； 如需减少孔隙率， 可 考虑增加压延或者离心处理。 本发明提供了一种新型锂离子电池隔膜， 能够实现如下技术效果： 其独特 的无纺布基材能够使得隔膜强度较大提高， 确保满足电池卷绕加工性， 提高电 池成品率。 特殊的有机聚合物包覆无机粒子结构能够使得电池隔膜的吸水性大 大减小， 降低了水分进入电池体系的可能性， 从而避免过多的水分与电解液发 生反应导致的电池鼓气、 内阻变大， 从而提升电池的倍率放电性能和使用寿命。 本发明还提供了一种新型锂离子电池隔膜的制备方法， 该方法操作简单、 成本 低， 制备出的产品水分含量少、 化学稳定性好、 机械强度高， 提升了电池的成 品率、 使用寿命和安全性。
下面结合附图及具体实施方式对本发明作进一步详细说明。
附图
图 1 : 实施例 1的改性无纺布锂离子电池隔膜的结构示意图。
1、 改性无纺布基材； 2、 填充剂。
具体实施方式
实施例 1 : 将 95g熔点为 250°C的高熔点 PET纤维， 5g熔点为 150 °C低熔点 PET纤维 利用湿法造纸方式抄造成无纺布纤维网层， 将无纺布纤维网层进行熔融结晶处 理， 温度为 155°C , 然后冷却， 制得孔隙率为 58%, 平均孔径为 llum, 穿刺强 度为 3.0N, 150°C lh热收缩为 1%, 厚度为 16um的改性无纺布基材 1 ; 取填充剂 2, 所述填充剂包括三氧化二铝、 PVDF;
将熔融结晶处理过的无纺布进行烘干， 烘干温度为 90°C , 时间为 lmin, 40g 粒径为 250nm的三氧化二铝放进烘箱， 温度为 100 °C。 时间为 4h。
将 20g熔点为 165°C的 PVDF、 500g的丙酮和 20g的乙醇混合加热搅拌，在 60°C加热搅拌至澄清， 将烘干过的三氧化二铝、 0.5gPVP和 lg含氟表面活性剂 加入混合液中， 继续搅拌 15-30min得到初步分散的浆料， 将该浆料放入分散仪 中分散 15-20分钟得到填充浆料。
将以上填充浆料釆用浸泡方式填充在具备双峰熔点的 PET改性无纺布基材 上， 静置 5-10min后， 放入烘箱干燥 10-20min, 得到初步的无纺布复合隔膜； 将上述初步无纺布复合隔膜在 160°C温度下热压， 得到本发明所述厚度为 20um的改性无纺布锂离子电池隔膜。 结合图 1 , 制得的改性无纺布锂离子电池 隔膜包括改性无纺布基材 1以及填充剂 2,其中填充剂 2填充在改性无纺布基材 1的孔内并往外延伸将整个改性无纺布基材 1包覆。
实施例 2:
按照实施例 1 的方法制备改性无纺布锂离子电池隔膜， 不同之处在于只添 加了 0.5g熔点为 150°C低熔点 PET纤维， 制得穿刺强度为 2.2N, 150°C lh热收 缩为 0.5%的无纺布基材。
实施例 3:
按照实施例 1 的方法制备改性无纺布锂离子电池隔膜， 不同之处在于添加 了 16.8g熔点为 150°C低熔点 PET纤维， 制得穿刺强度为 3.2N, 150°C lh热收缩 为 5%的无纺布基材。
实施例 4:
按照实施例 1 的方法制备改性无纺布锂离子电池隔膜， 不同之处在于填充 后的隔膜厚度跟未填充前的无纺布基材一样， 都是 16um。
实施例 5:
按照实施例 1 的方法制备改性无纺布锂离子电池隔膜， 不同之处在于釆用 熔喷的工艺制作改性无纺布基材。
实施例 6:
按照实施例 1的方法制备改性无纺布锂离子电池隔膜，不同之处在于将 40g 粒径为 250nm的三氧化二铝放进烘箱， 温度为 80°C , 时间为 lmin。
实施例 7:
按照实施例 1 的方法制备改性无纺布锂离子电池隔膜， 不同之处在于增加 了 20g粒径为 1200nm的硅灰石纤维颗粒。
实施例 8:
按照实施例 1 的方法制备改性无纺布锂离子电池隔膜， 不同之处在于有机 聚合物选用了熔点为 145 °C的 PVDF-HFP, 第一溶剂选用丁酮。
实施例 9:
按照实施例 1 的方法制备改性无纺布锂离子电池隔膜， 不同之处在于第一 填充材料釆用了粒径为 800nm的氢氧化镁。
实施例 10:
按照实施例 1 的方法制备改性无纺布锂离子电池隔膜， 不同之处在于后处 理工艺釆用将初步的无纺布复合隔膜浸没在水中（l-5 ) min, 而后干燥得到本发 明所述的改性无纺布锂离子电池隔膜。
实施例 11 :
按照实施例 1 的方法制备改性无纺布锂离子电池隔膜， 不同之处在于将初 步无纺布复合隔膜在 180°C温度下热压。
对比例 1 :
按照实施例 1的方法制备锂离子电池隔膜，不同之处在于没有添加 150°C低 熔点 PET材料制作改性无纺布基材。
对比例 2:
按照实施例 1 的方法制备锂离子电池隔膜， 不同之处在于添加了 24g熔点 为 150°C低熔点 PET材料制作改性无纺布基材。
对比例 3:
按照实施例 1 的方法制备锂离子电池隔膜， 不同之处在于无纺布基材及三 氧化二铝都没有经过烘干处理。
对比例 4:
按照实施例 1 的方法制备锂离子电池隔膜， 不同之处在于不经过任何后处 理工序。
对比例 5:
按照实施例 1 的方法制备锂离子电池复合隔膜， 不同之处在于基材釆用单 层 PE膜。
对比例 6:
普通陶瓷隔膜。
对比例 7:
普通无纺布隔膜。
电池性能测试：
正极釆用钴酸锂 LiCo02制成， 负极釆用石墨， 电池的电解液釆用碳酸乙烯 酯（EC ): 碳酸二乙酯（DEC ): 碳酸二曱酯（DMC )体积比 =1 :1 :1的溶液， 电 解液添加的溶质为 1 mol/L的六氟碑酸锂 LiPF6, 分别釆用实施例 1-6、 对比例 1-5的隔膜做电池性能评估。
含水量测试方法与测试结果：
每个实施例样品在 85 °C的烘箱中经过不同的烘烤时间， 分别为 6h、 12h、 24h、 48h, 而后对样品做含水量测试。 测试结果如表 1所示。
表 1 热收缩及强度基本性能测试结果
基本性能 150°C lh热收缩 （％) 穿刺强度 N 拉伸强度 MPa 实例 MD TD MD
实施例 1 2.0 1.0 3.1 58 实施例 2 1.0 0.5 2.3 40 实施例 3 6.0 5.0 3.3 70 实施例 4 1.5 0.8 3.0 65 实施例 5 2.8 1.0 2.8 65 实施例 6 2.2 1.2 3.1 57 实施例 7 2.0 1.0 3.4 57 实施例 8 3.0 2.0 2.9 56 实施例 9 2.2 1.2 3.2 58 实施例 10 2.0 1.0 3.2 60 实施例 11 2.2 1.1 3.5 70 对比例 1 1.8 0.8 1.0 30 对比例 2 10.0 8.2 3.4 68 对比例 3 2.0 1.2 3.0 57 对比例 4 2.2 1.2 2.2 38 对比例 5 8.0 4.2 3.5 90 对比例 6 9.5 5.4 3.2 88 对比例 7 3.0 2.0 0.8 28 从表 1 的测试结果表明， 与普通陶瓷隔膜相比， 本发明隔膜具有较低的热 收缩性能。 与对比例 1、 2、 4、 7相比， 由本发明所述无纺布基材的特定高低熔 点特点制得的隔膜， 在保证具有较低热收缩性能的同时又具有足够的穿刺拉伸 强度， 确保隔膜电池加工成品率及安全性。 不同烘烤时间后含水量测试结果
\^烤时间 6h烘烤后含水 12h 烘烤后含 24h 烘烤后含 48h 烘烤后含 实例 量 pm 水量 pm 水量 pm 水量 pm 实施例 1 492 325 202 165
实施例 2 490 320 200 162
实施例 3 494 330 212 180
实施例 4 432 292 195 156
实施例 5 482 315 192 155
实施例 6 892 625 402 265
实施例 7 502 334 210 169
实施例 8 494 328 205 166
实施例 9 390 258 188 126
实施例 10 528 346 212 175
实施例 11 490 322 200 162
对比例 1 485 315 198 160 对比例 2 498 332 210 169 对比例 3 1592 1125 802 565
对比例 4 1892 1325 912 765
对比例 5 692 425 305 262
对比例 6 3852 2520 1415 980
对比例 7 642 428 306 255 从表 2 的测试结果表明， 与普通陶瓷隔膜相比， 本发明隔膜含水量较低。 与对比例 3、 4、 6相比， 由本发明所述基材和填充结构组成的隔膜， 因加工的 特殊性以及有机聚合物包覆无机粒子的结构使得隔膜含水量较低， 需要较少的 烘烤时间。
耐绝缘性击穿短路测试方法与测试结果：
每个实施例制备 100个电池， 在制备电池的过程中， 电芯在 85 °C的真空烘 箱中烘烤 24h, 而后对电芯做耐绝缘性击穿短路测试， 并对不同电压测试的电池 通过个数进行统计。 测试结果如表 3所示。
表 3 耐绝缘性击穿短路测试结果
Figure imgf000017_0001
实施例 Ί 100 100 实施例 8 100 100 实施例 9 100 100 实施例 10 100 100 实施例 11 100 100 对比例 1 100 60
对比例 2 100 100 对比例 3 100 100 对比例 4 100 90
对比例 5 100 100 对比例 6 100 100 对比例 7 50 5 从表 3 的测试结果表明， 与普通无纺布隔膜相比， 本发明隔膜的耐绝缘性 较好， 250V击穿短路测试通过率达 100%, 而普通无纺布隔膜通过率为 5%。 与 对比例 1、 4相比， 由本发明所述基材和填充剂结构组成的隔膜， 因基材的特殊 性以及包覆性的填充剂结构使得隔膜耐绝缘性较大提高， 电池成品率提高。
安全性能测试方法以及测试结果：
每个实施例制备 100 个电池， 对电池做安全性能测试， 并对电池通过个数 以及测试情况进行统计。
热冲击： 按国标 GB/T18287-2013方法进行测试， 判断标准为不漏液、 不起 火、 不爆炸。
针刺： 在室温下， 以 0.5C电流恒流充电至充电限制电压 4.2V时， 转恒压充 电 3.5Η或电流降至 0.02C时截止充电， 将充电后的电池用直径为 3.0~8.0mm的 铁钉， 以 21-40mm/sec的速度垂直刺穿电池， 判断标准为不起火、 不爆炸。 短路：按国标 GB/T18287-2013方法进行测试，判断标准为不起火、不爆炸、 外表面温度低于 150 °C。 过充：按国标 GB/T18287-2013方法进行测试，判断标准为不起火、不爆炸。 测试结果如表 4所示。
安全测试结果
^则试项目 180 °C热冲击 针刺 ( 8mm ) 短路测试通过 3C/10V过充 实例 测试通过率％ 测试通过率％ 率0 /0 测试通过率％ 实施例 1 100 100 100 100 实施例 2 100 100 100 100 实施例 3 100 100 100 100 实施例 4 100 100 100 100 实施例 5 100 100 100 100 实施例 6 100 100 100 100 实施例 7 100 100 100 100 实施例 8 100 100 100 100 实施例 9 100 100 100 100 实施例 10 100 100 100 100 实施例 11 100 100 100 100 对比例 1 100 100 100 100 对比例 2 50 60 80 80 对比例 3 80 100 90 90 对比例 4 90 95 80 80 对比例 5 0 0 60 50 对比例 6 20 0 60 20 对比例 7 50 60 20 20 测试结果表明， 本发明隔膜所制备的电池在安全性能测试方面表现更 优越， 说明本发明隔膜具备良好的高温稳定性和安全性。 在出现热失控或者外 力撞击等意外时， 更能有效地避免电池起火爆炸等事故发生。
电性能测试方法以及测试结果：
每个实施例制备 100个电池， 对电池做电性能测试， 并取 10个电池测试数 据的平均值填入表 5。
倍率放电： 按国标 GB/T18287-2013方法进行测试。
循环性能：釆用仪器设备 BS-9300性能测试仪，以 1C倍率充放电循环测试， 釆用恒流恒压充电制度（CC-CV )和恒流放电制度，充放电电压范围 3.0 ~ 4.2 V, 首先以 1C恒流充电至 4.2 V,再以 4.2 V恒压下充电至电流小于 20 mA, 然后以 1C恒流放电至终止电压为 3.0 V, 如此循环 500次， 釆集循环数据。
内阻： 按国标 GB/T 18287-2013方法进行测试。
测试结果如表 5所示。
Figure imgf000020_0001
项目 倍率放电性能 60°C7天高温存储 500 内阻
1C 2C 3C 4C 5C 次循
容量 容量 厚度 m。
/0.5C /0.5C /0.5C /0.5C /0.5C 保持 恢复 膨胀 环0 /0 实例 % % % % % 率0 /0 率0 /0 率0 /0
实施例 1 99.5 95.0 90.0 83.0 75.0 98.5 99.5 4 87.0 17.0 实施例 2 99.6 96.5 90.8 83.2 76.2 98.8 99.6 4 87.5 16.8 实施例 3 99.0 94.5 89.0 81.5 74.0 98.0 99.0 4 86.0 17.5 实施例 4 99.5 95.5 91.0 85.0 77.5 97.0 98.5 5 86.5 16.5 实施例 5 99.2 95.8 90.5 84.0 76.0 97.5 98.8 4 86.8 16.8 实施例 6 99.0 94.2 88.5 81.0 73.0 96.0 97.5 6 85.0 18.0 实施例 7 99.2 95.2 91.0 83.8 76.0 97.5 98.8 4 86.8 17.0 实施例 8 99.0 96.0 92.5 85.0 78.0 97.0 98.5 4 86.0 16.8 实施例 9 98.0 93.0 87.5 80.2 72.0 96.5 98.0 5 84.5 18.0 实施例 10 98.5 94.5 88.5 81.0 74.5 97.0 98.0 5 85.5 17.5 实施例 11 99.0 95.0 92.0 85.5 78.0 96.5 98.0 5 87.5 16.5 对比例 1 99.6 95.6 91.0 83.5 76.5 98.5 99.5 4 87.0 17.0 对比例 2 98.5 93.0 88.0 80.5 73.0 98.0 99.0 4 86.0 17.2 对比例 3 97.0 90.5 81.0 70.5 59.5 93.0 94.5 10 79.5 20.5 对比例 4 97.5 91.5 80.5 71.0 60.5 93.5 95.0 9 80.0 19.8 对比例 5 98.5 94.5 89.5 82.0 74.5 97.0 98.0 5 85.0 18.8 对比例 6 97.0 89.0 79.5 68.0 55.0 92.0 93.0 12 75.0 23.0 对比例 7 99.5 96.0 91.0 83.5 76.8 88.0 90.5 15 76.5 16.5 表 5测试结果表明， 本发明隔膜所制备的电池内阻更小、 高倍率放电性能和 循环性能更优异。 本发明所述基材和填充剂赋予隔膜均勾的厚度和孔径大小、 良好的电化学稳定性、 优异的吸液保液能力以及极小的吸水性， 使得本发明隔 膜所制备的电池具备优异的倍率放电性能和循环寿命。 上述实施方式仅为本发明的优选实施方式， 不能以此来限定本发明保护的 范围， 本领域的技术人员在本发明的基础上所做的任何非实质性的变化及替换 均属于本发明所要求保护的范围。

Claims

权 利 要 求 书
1. 一种新型改性无纺布锂离子电池隔膜， 其特征在于： 所述隔膜包括改性 无纺布基材及其复合的填充剂：
所述改性无纺布基材：
其上分布有均匀排列的大小为 l-50000nm的孔， 孔隙率为 30-95%;
其包括低熔点材料和高熔点材料： 所述低熔点材料经过熔融结晶处理， 高 熔点材料为改性无纺布基材总重量的 85-99.9%,其余为低熔点物质； 所述高熔点 材料为熔点为 > 200°C的聚酯、 聚烯烃、 腈聚合物、 聚酰亚胺、 聚酸中的一种或 多种混合制成， 所述低熔点物质为熔点为 50-199°C的聚烯烃、 聚乙烯醇、 热粘合 聚酯、 聚苯乙烯、 氟类聚合物中的一种或多种混合制成；
所述改性无纺布基材上复合的填充剂， 包括有机聚合物， 以及第一填充材 料和第二填充材料中的一种或者两种混合：
所述有机聚合物为氟类聚合物、 橡胶、 酯类聚合物、 纤维素和淀粉中的一 种或者两种以上的組合；
所述第一填充材料， 其为粒径 l-2000nm的无机颗粒， 所述无机颗粒为无机 氧化物纳米颗粒、 无机氮化物纳米颗粒、 矿石纳米颗粒中的一种或两种以上的 组合；
所述第二填充材料， 其为粒径 l-10000nm的纤维颗粒， 所述纤维颗粒为硅灰 石纤维、 玻璃纤维、 木质素、 纤维素纳米纤维、 腈纶纤维、 锦纶纤维、 涤纶纤 维、 芳纶纤维、 聚酰亚胺纤维中的一种或者两种以上的组合；
所述填充剂填充在改性无纺布基材的孔内。
2. 根据权利要求 1所述的新型改性无纺布锂离子电池隔膜， 其特征在于： 所 述填充剂从改性无纺布基材的孔内往外延伸将整个改性无纺布基材包覆；
所述隔膜的厚度为改性无纺布基材厚度的 1-10倍。
3. 根据权利要求 2所述的新型改性无纺布锂离子电池隔膜， 其特征在于： 所 述隔膜的厚度为改性无纺布基材厚度的 1 -2倍。
4. 根据权利要求 1所述的新型改性无纺布锂离子电池隔膜， 其特征在于： 所述第一填充材料的粒径为 10-1000nm , 所述第二填充材料的粒径为 100-5000nm。
5. 根据权利要求 1所述的新型改性无纺布锂离子电池隔膜， 其特征在于： 所述熔融结晶处理是指将低熔点材料在其熔点之上 0-10°C的温度下加热使其熔 融， 然后降温使其冷却结晶。
6. 根据权利要求 1-5任一项所述的新型改性无纺布锂离子电池隔膜的制备 方法， 其特征在于包括如下步骤：
a. 制作无纺布纤维层：将高熔点材料和低熔点材料加工制成无纺布纤维层， 所述加工工艺为熔喷、 纺粘法、 湿法造纸、 水刺、 针刺、 热轧法中的一种， 其 中高熔点材料重量占制成无纺布纤维层总重量的 85-99.9%,余量为低熔点材料； 所述高熔点材料为熔点> 200 的聚酯、 聚烯烃、 腈聚合物、 聚酰亚胺、 聚 醚中的一种或多种；
所述低熔点材料为熔点为 50-199 °C的聚烯烃、 聚乙烯醇、 热粘合聚酯、 聚 苯乙烯、 氟类聚合物中的一种或多种；
b. 制作改性无纺布基材：将步骤 a所得的无纺布纤维层进行熔融结晶处理； 所述熔融结晶处理是指将低熔点材料在步骤 a 中所使用低熔点材料的熔点 之上 0-10°C的温度下加热使其熔融， 然后降温使其冷却结晶的过程；
c 制备填充剂浆料： 将第一填充材料和 /或第二填充材料进行烘干处理， 将 有机聚合物、 第一溶剂和第二溶剂按照重量比为 1 : ( 5 ~ 50 ): ( 0.1 ~ 10 )混合， 搅拌加热溶解至澄清， 然后添加经过烘干处理的第一填充材料和 /或第二填充材 料， 混合均匀；
所述有机聚合物为氟类聚合物、 橡胶、 酯类聚合物、 纤维素、 淀粉中的一 种或者两种以上的组合；
所述第一溶剂为酮类溶剂、 酰胺类溶剂和酯类溶剂的一种或者两种以上混 合；
所述第二溶剂为水、 醇溶剂、 [¾代烃溶剂中的一种或者两种以上混合； d. 填充无纺布： 将 C步骤制得的填充剂浆料在经 b步骤制得的改性无纺布 基材上进行填充；
e. 去除溶剂： 将经过 d步骤加工的无纺布纤维层进行萃取或干燥， 得到初 步的无纺布锂离子电池隔膜；
f. 后处理： 将经过 e步骤制得的初步的无纺布锂离子电池隔膜加热至所述 有机聚合物熔点以上 5-30 °C ;
或者浸浴在第三溶剂中， 所述第三溶剂为水、 酮类溶剂、 酰胺类溶剂、 酯 类溶剂、 醇溶剂和 [¾代烃溶剂中的一种或者两种以上混合。
7. 根据权利要求 6所述的新型改性无纺布锂离子电池隔膜的制备方法， 其 特征在于： 所述 c步骤中：
所述第一填充材料、 第二填充材料的总重量与有机聚合物的重量比为（1 :5 ) - ( 5:1 );
第二填充材料占第一填充材料、 第二填充材料的总重量的比例为 0-50%。
8. 根据权利要求 6所述的新型改性无纺布锂离子电池隔膜的制备方法， 其 特征在于： 在所述 c 步骤中添加助剂， 所述助剂为分散剂、 消泡剂、 表面活性 剂中的一种或两种以上的组合。
9. 根据权利要求 6所述的新型改性无纺布锂离子电池隔膜的制备方法， 其 特征在于： 所述 d步骤填充釆用淋膜、 浸泡、 挤压、 浇铸、 辊涂、 刮涂或凹版 涂布。
10. 根据权利要求 6 所述的新型改性无纺布锂离子电池隔膜的制备方法， 其特征在于： 将制得的新型改性无纺布锂离子电池隔膜进行机械处理， 所述机 械处理为热压延、 离心、 拉伸中的一种或多种。
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WO2018101474A1 (ja) * 2016-12-02 2018-06-07 旭化成株式会社 非水電解質電池用無機粒子
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