WO2014044040A1 - Composite negative electrode sheet for lithium ion battery and preparation method therefor and lithium ion battery - Google Patents

Composite negative electrode sheet for lithium ion battery and preparation method therefor and lithium ion battery Download PDF

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Publication number
WO2014044040A1
WO2014044040A1 PCT/CN2013/073487 CN2013073487W WO2014044040A1 WO 2014044040 A1 WO2014044040 A1 WO 2014044040A1 CN 2013073487 W CN2013073487 W CN 2013073487W WO 2014044040 A1 WO2014044040 A1 WO 2014044040A1
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negative electrode
electrode sheet
lithium ion
ion battery
composite negative
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PCT/CN2013/073487
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French (fr)
Chinese (zh)
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叶海林
张光辉
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华为技术有限公司
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Publication of WO2014044040A1 publication Critical patent/WO2014044040A1/en

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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/04Processes of manufacture in general
    • H01M4/043Processes of manufacture in general involving compressing or compaction
    • H01M4/0435Rolling or calendering
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/13Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/133Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • H01M50/491Porosity
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/13Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/13Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139Processes of manufacture
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/13Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139Processes of manufacture
    • H01M4/1393Processes of manufacture of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409Separators, membranes or diaphragms characterised by the material
    • H01M50/411Organic material
    • H01M50/414Synthetic resins, e.g. thermoplastics or thermosetting resins
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409Separators, membranes or diaphragms characterised by the material
    • H01M50/44Fibrous material
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/05Accumulators with non-aqueous electrolyte
    • H01M10/052Li-accumulators
    • H01M10/0525Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/64Carriers or collectors
    • H01M4/66Selection of materials
    • H01M4/661Metal or alloys, e.g. alloy coatings
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/46Separators, membranes or diaphragms characterised by their combination with electrodes
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10Energy storage using batteries

Definitions

  • the present invention relates to the field of lithium ion batteries, and in particular to a composite negative electrode sheet for a lithium ion battery, a preparation method thereof and a lithium ion battery. Background technique
  • Lithium-ion batteries have been widely used in mobile phones, notebook computers, etc. due to their advantages of light weight, small size, high operating voltage, high energy density, high output power, high charging efficiency and no memory effect.
  • a lithium ion battery usually consists of a positive electrode sheet, a negative electrode sheet, a separator, an electrolyte, and an outer casing.
  • the separator is mainly a commercially available commercial polyethylene (PE) film or a polypropylene (PP) film having a thickness of 20 to 40 ⁇ m, a porosity of about 40%, and a separator interval of the positive electrode and the negative electrode.
  • PE polyethylene
  • PP polypropylene
  • the preparation method of the existing lithium ion battery is generally prepared by separately preparing a positive electrode sheet, a negative electrode sheet and a separator, and then winding the separator and the positive and negative electrode sheets, after being assembled and packaged, injecting and sealing, finally activating and performing performance test.
  • the separator is usually a light, soft and thin film, which is not easily aligned with the positive and negative pole pieces during the winding assembly process, and is often liable to cause short circuit between the positive and negative pole pieces, and at the same time, in the winding During the assembly process, tension is easily generated to cause the core to deform, and as the number of cycles increases, the lithium ion battery changes. The shape will also be aggravated and the capacity will be attenuated.
  • polyolefin films such as commercially available polyethylene films or polypropylene films have poor thermal stability, which causes safety hazards in lithium ion batteries. This is because one of the safety measures for lithium-ion batteries is to interrupt the current, that is, when the internal temperature of the lithium-ion battery is high, the polymer membrane having a porous structure should be able to generate a melting to automatically close the porous structure, thereby rapidly increasing the impedance. Current interruption.
  • the thermal stability of polyolefin film is poor.
  • the self-closing temperature of polyethylene film is 135 ⁇ 140 °C
  • the self-closing temperature of polypropylene film is about 170 °C
  • a large volume shrinkage is easy to cause the diaphragm area to shrink. Small and easily destroyed, causing a short circuit in the lithium-ion battery, causing the battery to explode or catch fire.
  • the separator with the electrode sheet, such as the inorganic oxide CN101246958A, which is directly coated on the carbon negative electrode sheet of the lithium battery to form a composite electrode sheet having a microporous coated separator, and then wound with the positive electrode sheet.
  • the composite electrode sheet prepared by the preparation method contains a hydrophilic polymer, which results in the composite electrode sheet being extremely easy to absorb water, and the added inorganic oxide has a high specific surface area and a strong surface adsorption capacity, and also results in a composite electrode.
  • the first aspect of the embodiments of the present invention provides a composite negative electrode sheet for a lithium ion battery, which is used to solve the internal short circuit and the core deformation of the battery which are easily caused by the winding arrangement of the diaphragm and the positive and negative pole pieces in the prior art.
  • the problem and can improve the safety performance and cycle life of lithium-ion batteries.
  • the second aspect provides a method for preparing the composite negative electrode sheet for a lithium ion battery.
  • a third aspect of the present invention provides a lithium ion battery comprising the composite negative electrode sheet for a lithium ion battery.
  • an embodiment of the present invention provides a composite negative electrode sheet for a lithium ion battery, wherein the composite negative electrode sheet for a lithium ion battery is composed of a negative electrode sheet and a separator composited on a surface of the negative electrode sheet, and the negative electrode sheet is assembled.
  • the fluid is composed of a negative active material coated on a surface of the current collector, and the separator is a polyimide nanofiber membrane.
  • the polyimide nanofiber film has a thickness of 5 ⁇ m to 30 ⁇ m.
  • the polyimide nanofiber membrane has a porosity of 5% to 80% and a pore diameter of ⁇ . ⁇ ⁇ ⁇ ! ⁇ 10 ⁇ m.
  • the current collector is a copper foil or an aluminum foil.
  • the negative electrode active material is any organic compound or inorganic material capable of deintercalating lithium ions.
  • the first aspect of the embodiment of the present invention overcomes the problems of the internal short circuit and the deformation of the battery caused by the winding arrangement of the separator and the positive and negative pole pieces in the prior art.
  • the separator is a porous polymer material polyimide nanofiber.
  • the film which has good heat resistance and can improve the safety performance and cycle life of the lithium ion battery, is suitable for high capacity and power batteries.
  • an embodiment of the present invention provides a method for preparing a composite negative electrode sheet for a lithium ion battery, comprising the steps of: spraying a polyamic acid solution on the surface of the negative electrode sheet by electrospinning, and then performing mechanical rolling, Finally, the thermal imidization treatment converts the polyamic acid sprayed on the surface of the negative electrode sheet into polyimide, and forms a polyimide nanofiber film on the surface of the negative electrode sheet to obtain a composite negative electrode sheet for a lithium ion battery.
  • the polyamic acid solution is prepared as follows: a dibasic organic acid anhydride and an organic diamine are added to an organic solvent, stirred, and a condensation reaction is carried out to obtain a polyamic acid solution.
  • the dibasic organic acid anhydride is pyromellitic acid dianhydride (PMDA), biphenyltetracarboxylic dianhydride (S-BPDA), isopropyl diphthalic anhydride (IPDA), oxybiphenyl tetraphthalic acid dianhydride ( One or more of ODPA), benzophenonetetracarboxylic dianhydride (BTDA) and bisphenol A diether dianhydride (BPADA).
  • the organic diamine is 4,4-diaminodiphenyl ether (4,4-ODA), 3,4-diaminodiphenyl ether (3,4-ODA), m-phenylenediamine (MDA), One or more of p-phenylenediamine (PDA), 3,3-diphenylsulfone diamine (3,3-SDA), biphenyldiamine (BPDA), and isopropyldiphenylamine (IPDA).
  • 4,4-ODA 4,4-diaminodiphenyl ether
  • 3,4-ODA 3,4-diaminodiphenyl ether
  • MDA m-phenylenediamine
  • PDA p-phenylenediamine
  • BPDA biphenyldiamine
  • IPDA isopropyldiphenylamine
  • the organic solvent is hydrazine, hydrazine-dimercaptocarboxamide (DMF), hydrazine, hydrazine-dimercaptoacetamide (DMAc), N-2-mercaptopyrrolidone (NMP), tetrahydrofuran (THF) and hydrazine One or several of the alcohols.
  • the molar ratio of the dibasic organic acid anhydride to the organic diamine is 0.7 to 1.1:1, and the organic solvent is added in an amount of 5 to 8 times the total mass of the dibasic organic acid anhydride and the organic diamine.
  • the temperature of the stirring process is from 0 ° C to 30 ° C, and the stirring time is from 2 to 10 hours.
  • the electrospun spinning needle has a diameter of 0.2 mm to 1.5 mm, a voltage of 100 v to 20 kV, and a distance between the needle and the receiving electrode of 10 cm to 35 cm, and a spinning flow rate. 0.2 to 1 ml / hour.
  • the mechanical rolling has a strength of 1 to 15 MPa, a speed of 0.5 to 1 m/min, and a rolling time of 1 to 5 minutes.
  • the thermal imidization treatment is carried out by gradient heating under nitrogen, argon or vacuum, and the gradient heating is: 100 to 200 ° C for 0.5 to 2 hours, 200 to 250 ° C for 0.5 to 2 hours, 250 to 300 °. C is kept for 0.5 ⁇ 1.5 hours.
  • the thickness of the polyimide nanofiber film is 5 ⁇ to 30 ⁇ .
  • the polyimide nanofiber membrane has a porosity of 5% to 80% and a pore diameter of ⁇ . ⁇ ⁇ ! ⁇ 10 ⁇ m.
  • the negative electrode sheet is composed of a current collector and a negative electrode active material coated on the surface of the current collector.
  • the current collector is a copper foil or an aluminum foil.
  • the negative electrode active material is any organic compound or inorganic material capable of deintercalating lithium ions.
  • the composite negative electrode sheet for a lithium ion battery is prepared by directly laminating the separator on the negative electrode sheet, which simplifies the preparation of the positive and negative electrode sheets and the separator separately in the prior art, and then the separator and the positive and negative electrode sheets are required.
  • the winding process is carried out, and at the same time, the problems of internal short circuit and battery core deformation which are easily caused by the separator and the positive and negative pole piece winding arrangements in the prior art are overcome, and the safety performance and cycle life of the lithium ion battery can be improved. It is therefore suitable for high capacity and power batteries.
  • an embodiment of the present invention provides a lithium ion battery, which is composed of a composite negative electrode sheet for a lithium ion battery, a positive electrode sheet, a nonaqueous electrolyte, and an outer casing, wherein the composite negative electrode sheet for the lithium ion battery is composed of a negative electrode sheet and a composite A separator composed of a separator on a surface of the negative electrode sheet, the negative electrode sheet being composed of a current collector and an anode active material coated on a surface of a current collector, the separator being a polyimide nanofiber membrane.
  • the polyimide nanofiber membrane has a thickness of 5 ⁇ to 30 ⁇ .
  • the polyimide nanofiber membrane has a porosity of 5% to 80% and a pore diameter of ⁇ . ⁇ ⁇ ⁇ ! ⁇ 10 ⁇ m.
  • the current collector is a copper foil or an aluminum foil.
  • the negative electrode active material is any organic compound or inorganic material capable of deintercalating lithium ions.
  • the positive electrode sheet is composed of a current collector and a positive electrode active material coated on the surface of the current collector, and the positive electrode active material is an organic compound or an inorganic material which can deintercalate lithium ions.
  • the non-aqueous electrolyte is an electrolyte of a carbonate solvent, and the electrolyte contains a lithium salt selected from the group consisting of ethylene carbonate (EC), propylene carbonate (PC), and dinonyl carbonate ( One or more of DMC) and cesium carbonate (EMC) selected from the group consisting of LiPF 6 , LiBF 4 , LiSbF 6 , LiC10 4 , LiCF 3 S0 3 , LiA10 4 , LiAlCl 4 , Li ( CF ) 3 S0 2 ) 2 One or more of N, LiBOB and LiDFOB.
  • the outer casing is an aluminum plastic film, a steel shell, an aluminum shell or a plastic shell.
  • the composite negative electrode sheet for a lithium ion battery since the composite negative electrode sheet for a lithium ion battery has been compounded with a separator, it is not necessary to separately provide a separator, and the separator and the positive and negative electrode sheets are not separately wound, and the separator is a porous polymer material.
  • the imide nanofiber membrane has good heat resistance and can improve the safety performance and cycle life of the lithium ion battery. Therefore, the lithium ion battery provided by the third aspect of the embodiment of the invention is easy to prepare, and has excellent safety performance and long The service life can be used as a high capacity and power battery.
  • Fig. 1 is a flow chart showing a method of preparing a composite negative electrode sheet for a lithium ion battery according to an embodiment of the present invention.
  • the following is a preferred embodiment of the embodiments of the present invention. It should be noted that those skilled in the art can make some improvements and refinements without departing from the principles of the embodiments of the present invention. These improvements and retouchings are also considered to be the scope of protection of the embodiments of the present invention.
  • the first aspect of the embodiments of the present invention provides a composite negative electrode sheet for a lithium ion battery, which solves the problems of internal short circuit and battery core deformation caused by the separator and the positive and negative pole piece winding arrangements in the prior art, and Improves the safety and cycle life of lithium-ion batteries.
  • a second aspect of the present invention provides a method for preparing the composite negative electrode sheet for a lithium ion battery.
  • a third aspect of the present invention provides a lithium ion battery comprising the composite negative electrode sheet for a lithium ion battery.
  • an embodiment of the present invention provides a composite negative electrode sheet for a lithium ion battery, wherein the composite negative electrode sheet for a lithium ion battery is composed of a negative electrode sheet and a separator composited on a surface of the negative electrode sheet, and the negative electrode sheet
  • the current collector is composed of a current collector and an anode active material coated on the surface of the current collector
  • the separator is a polyimide nanofiber membrane.
  • the polyimide nanofiber film has a thickness of 5 ⁇ to 30 ⁇ .
  • the polyimide nanofiber membrane is thinner and takes up less space inside the battery when used for preparing a lithium ion battery, thereby increasing the capacity density of the lithium ion battery.
  • Porosity relates to the number of holes per unit area, and the size of the pores relates to the ability of ions to shuttle therethrough.
  • the polyimide nanofiber membrane has a porosity of 5% to 80% and a pore diameter of ⁇ . ⁇ ⁇ ⁇ ! ⁇ 10 ⁇ ⁇ . At this time, the ion current can be quickly passed, thereby completing the rapid transfer of lithium ions between the positive and negative pole pieces during electrochemical charging and discharging.
  • the current collector is copper foil or aluminum foil.
  • the negative electrode active material is any organic compound or inorganic material capable of deintercalating lithium ions, such as a carbon material.
  • the first aspect of the embodiment of the present invention overcomes the problems of the internal short circuit and the deformation of the battery caused by the winding arrangement of the separator and the positive and negative pole pieces in the prior art.
  • the separator is a porous polymer material polyimide nanofiber.
  • the film which has good heat resistance and can improve the safety performance and cycle life of the lithium ion battery, is suitable for high capacity and power batteries.
  • an embodiment of the present invention provides a method for preparing a composite negative electrode sheet for a lithium ion battery.
  • the method includes the following steps: spraying a polyamic acid solution on the surface of the negative electrode sheet by electrospinning. Then, mechanical rolling is performed, and finally, the thermal imidization treatment converts the polyamic acid sprayed on the surface of the negative electrode sheet into polyimide, and forms a polyimide nanofiber film on the surface of the negative electrode sheet to obtain a composite negative electrode sheet for a lithium ion battery.
  • the polyamic acid solution is prepared by adding a dibasic organic acid anhydride and an organic diamine to an organic solvent, stirring, and a condensation reaction to obtain a polyamic acid solution.
  • the dibasic organic acid anhydride is benzoic acid succinic anhydride (PMDA), biphenyltetracarboxylic dianhydride (S-BPDA), and One or more of propyl diphenyl anhydride (IPDA ), oxydiphenyltetradecanoic acid (ODPA), benzophenone tetraacid dianhydride (BTDA), and bisphenol A diether dianhydride (BPADA).
  • PMDA benzoic acid succinic anhydride
  • S-BPDA biphenyltetracarboxylic dianhydride
  • IPDA propyl diphenyl anhydride
  • ODPA oxydiphenyltetradecanoic acid
  • BTDA benzophenone tetraacid dianhydride
  • BPADA bisphenol A diether dianhydride
  • the organic diamine is 4,4-diaminodiphenyl ether (4,4-ODA), 3,4-diaminodiphenyl ether (3,4-00%), m-phenylenediamine (MDA), p-phenylene
  • 4,4-ODA 4,4-diaminodiphenyl ether
  • MDA 3,4-diaminodiphenyl ether
  • MDA m-phenylenediamine
  • PDA 4,4-diaminodiphenyl ether
  • PDA 4,4-diaminodiphenyl ether
  • 3,4-00% 3,4-diaminodiphenyl ether
  • MDA m-phenylenediamine
  • MDA m-phenylenediamine
  • PDA 4,4-diaminodiphenyl ether
  • PDA 4,4-diaminodiphenyl ether
  • BPDA 4,4-diaminodiphenyl ether
  • the organic solvent is one of hydrazine, hydrazine-dimercaptocarboxamide (DMF), hydrazine, hydrazine-dimercaptoacetamide (DMAc), N-2-mercaptopyrrolidone (NMP), tetrahydrofuran (THF) and decyl alcohol.
  • DMF hydrazine-dimercaptocarboxamide
  • DMAc hydrazine
  • DMAc hydrazine-dimercaptoacetamide
  • NMP N-2-mercaptopyrrolidone
  • THF tetrahydrofuran
  • decyl alcohol decyl alcohol
  • the molar ratio of the dibasic organic acid anhydride to the organic diamine is 0.7 to 1.1:1, and the organic solvent is added in an amount of 5 to 8 times the total mass of the dibasic organic acid anhydride and the organic diamine.
  • the temperature of the stirring process is 0 ° C to 30 ° C, and the stirring time is 2 to 10 hours.
  • the spinning needle of the electrospinning has a diameter of 0.2 mm to 1.5 mm, a voltage of 100 v to 20 kV, a distance between the needle and the receiving electrode of 10 cm to 35 cm, and a spinning flow rate of 0.2 to 1 ML/hr.
  • the mechanical rolling strength is 1 to 15 MPa, the speed is 0.5 to 1 m / min, and the rolling time is 1 to 5 minutes.
  • the thermal imidization treatment is carried out by gradient heating under nitrogen, argon or vacuum.
  • the gradient temperature is: 100 ⁇ 200 °C for 0.5 ⁇ 2 hours, 200 ⁇ 250 °C for 0.5 ⁇ 2 hours, 250 ⁇ 300 °C for 0.5. ⁇ 1.5 hours.
  • the polyimide nanofiber membrane has a thickness of 5 ⁇ m to 30 ⁇ m.
  • the polyimide nanofiber membrane has a porosity of 5% to 80% and a pore diameter of 0.01 ⁇ ⁇ ! ⁇ 10 ⁇ ⁇ .
  • the negative electrode sheet is composed of a current collector and a negative electrode active material coated on the surface of the current collector.
  • the current collector is copper foil or aluminum foil.
  • the negative electrode active material is any organic compound or inorganic material capable of deintercalating lithium ions.
  • the separator is directly composited on the negative electrode sheet to prepare a composite for a lithium ion battery.
  • the negative electrode sheet simplifies the prior art process of separately preparing the positive and negative electrode sheets and the separator and then needs to wind the separator and the positive and negative electrode sheets, while overcoming the prior art diaphragm and positive and negative pole coils. It is easy to solve the problem of internal short circuit of the battery and deformation of the battery core, and can improve the safety performance and cycle life of the lithium ion battery, and thus is suitable for high capacity and power batteries.
  • an embodiment of the present invention provides a lithium ion battery, which is composed of a composite negative electrode sheet for a lithium ion battery, a positive electrode sheet, a nonaqueous electrolyte, and an outer casing, wherein the composite negative electrode sheet for the lithium ion battery is composed of a negative electrode sheet and a composite A separator composed of a separator on a surface of the negative electrode sheet, the negative electrode sheet being composed of a current collector and an anode active material coated on a surface of a current collector, the separator being a polyimide nanofiber membrane.
  • the polyimide nanofiber membrane has a thickness of 5 ⁇ m to 30 ⁇ m.
  • the polyimide nanofiber membrane has a porosity of 5% to 80% and a pore diameter of 0.01 ⁇ ⁇ ! ⁇ 10 ⁇ ⁇ .
  • the current collector is copper foil or aluminum foil.
  • the negative electrode active material is any organic compound or inorganic material capable of deintercalating lithium ions.
  • the positive electrode sheet is composed of a current collector and a positive electrode active material coated on the surface of the current collector, and the positive electrode active material is an organic compound or an inorganic material which can deintercalate lithium ions.
  • the nonaqueous electrolyte is an electrolyte of a carbonate solvent containing a lithium salt selected from the group consisting of ethylene carbonate (EC), propylene carbonate (PC), dinonyl carbonate (DMC), and One or more of ethyl lanthanum carbonate (EMC) selected from the group consisting of LiPF 6 , LiBF 4 , LiSbF 6 , LiC10 4 , LiCF 3 S0 3 , LiA10 4 , LiAlCl 4 , Li ( CF 3 S0 2 One or more of 2 N, LiBOB and LiDFOB.
  • a lithium salt selected from the group consisting of ethylene carbonate (EC), propylene carbonate (PC), dinonyl carbonate (DMC), and One or more of ethyl lanthanum carbonate (EMC) selected from the group consisting of LiPF 6 , LiBF 4 , LiSbF 6 , LiC10 4 , LiCF 3 S0 3 , LiA10 4
  • the outer casing is an aluminum plastic film, a steel shell, an aluminum shell or a plastic shell.
  • the composite negative electrode sheet and the positive electrode sheet for the lithium ion battery are cut to a certain size, and then the composite negative electrode sheet and the positive electrode sheet for the lithium ion battery are wound and pre-sealed with an aluminum plastic film to obtain a 423485 square type battery core, which is then completed.
  • the square-wound soft-packed battery is finally filled with a non-aqueous electrolyte to produce a lithium-ion battery.
  • the separator is a porous polymer material.
  • the imide nanofiber membrane has good heat resistance and can improve the safety performance and cycle life of the lithium ion battery. Therefore, the lithium ion battery provided by the third aspect of the embodiment of the invention is easy to prepare, and has excellent safety performance and long The service life can be used as a high capacity and power battery.
  • the preparation method of the composite negative electrode sheet for a lithium ion battery comprises the following steps:
  • a mixture of negative active material artificial graphite, 3 g of binder styrene butadiene rubber (SBR) and 3 g of carboxymethylcellulose (CMC) was added to 200 g of water, and then stirred in a vacuum mixer to form a uniform slurry. .
  • the slurry was uniformly coated on both sides of a 9 ⁇ m copper foil, and the coated surface density was controlled to be 17.8 mg/cm 2 , and then dried at 100 ° C, and pressed to obtain a negative electrode sheet having a thickness of 120 ⁇ m.
  • the polyamic acid solution was electrospun onto a prepared negative electrode sheet having a needle diameter of 1.5 mm, a spinning voltage of 20 kV, a needle to negative electrode sheet distance of 18 cm, electrospinning for 1 hour, and then passing through 90 °C oven pre-drying, and then rolling through the roller press, the pressure is 15 MPa, the speed is 0.5 m / Minutes, rolling for 5 minutes, controlling the thickness of the polyamic acid nanofiber film to 30 ⁇ , heating the polyamic acid to polyimide under heating in a nitrogen atmosphere, and maintaining the heating temperature at 200 ° C for 0.5 hour, 250 °
  • the mixture was kept at 0.5 hour for 0.5 hour and at 350 ° C for 0.5 hour to obtain a composite negative electrode sheet for a lithium ion battery having a polyimide nanofiber film.
  • the composite negative electrode sheet for a lithium ion battery prepared in this embodiment is composed of a negative electrode sheet and a separator directly laminated on the surface of the negative electrode sheet, and the negative electrode sheet is composed of a current collector and a negative electrode active material coated on the surface of the current collector, and the separator is a polyacyl group.
  • Imine nanofiber membrane The polyimide nanofiber membrane has a thickness of 30 ⁇ m.
  • the polyimide nanofiber membrane has a porosity of 70% and a pore diameter of 10 ⁇ m.
  • the composite negative electrode sheet for a lithium ion battery obtained in Example 1 was cut to a size of 405 mm ⁇ 80 mm, which contained 5.3 g of active ingredient artificial graphite.
  • the composite negative electrode sheet and the positive electrode sheet for lithium ion battery cut into a certain shape are pre-sealed by aluminum plastic film to obtain a 423485 square type battery core, and then the square-wound soft-pack battery is completed, and finally the non-water is injected.
  • the non-aqueous electrolyte is ethylene carbonate: mercaptoethyl carbonate: a mixed solution of diethyl carbonate in a volume ratio of 1:1:1, containing 1 mol of lithium hexafluorophosphate,
  • a lithium ion battery has a design capacity of 1600 mAh.
  • the preparation method of the composite negative electrode sheet for a lithium ion battery comprises the following steps: (1) Synthesis of polyamic acid solution
  • a mixture of negative active material artificial graphite, 3 g of binder styrene butadiene rubber (SBR) and 3 g of carboxymethylcellulose (CMC) was added to 200 g of water, and then stirred in a vacuum mixer to form a uniform slurry. .
  • the slurry was uniformly coated on both sides of a 9 ⁇ m copper foil, and the coated surface density was controlled to be 17.8 mg/cm 2 , and then dried at 100 ° C, and pressed to obtain a negative electrode sheet having a thickness of 120 ⁇ m.
  • the polyamic acid solution was electrospun onto the prepared negative electrode sheet, the needle diameter was 1 mm, the spinning voltage was 1000 volts, the distance from the needle to the negative electrode sheet was 20 cm, electrospinning was 0.8 hour, and then passed through 90°.
  • the C oven is pre-baked and then rolled by a roller press at a pressure of 5 MPa, a speed of 0.8 m/min, and a rolling pressure of 3 minutes.
  • the polyamic acid nanofiber film is controlled to have a thickness of 15 ⁇ m and heated under an argon atmosphere.
  • the polyamic acid is converted into a polyimide, and the heating temperature is maintained at 150 ° C for 1 hour, at 220 ° C for 1 hour, and at 300 ° C for 1 hour to obtain lithium having a polyimide nanofiber membrane.
  • the composite negative electrode sheet for a lithium ion battery is composed of a negative electrode sheet and a separator directly laminated on the surface of the negative electrode sheet, and the negative electrode sheet is composed of a current collector and a negative electrode active material coated on the surface of the current collector, and the separator is a polyimide nanofiber membrane.
  • the polyimide nanofiber membrane has a thickness of 15 ⁇ m.
  • the polyimide nanofiber membrane has a porosity of 60% and a pore diameter of 1 ⁇ m.
  • the preparation method of the lithium ion battery is the same as that in the first embodiment.
  • Embodiment 3 The preparation method of the composite negative electrode sheet for a lithium ion battery comprises the following steps:
  • a mixture of negative active material artificial graphite, 3 g of binder styrene butadiene rubber (SBR) and 3 g of carboxymethylcellulose (CMC) was added to 200 g of water, and then stirred in a vacuum mixer to form a uniform slurry. .
  • the slurry was uniformly coated on both sides of a 9 ⁇ m copper foil, and the coated surface density was controlled to be 17.8 mg/cm 2 , and then dried at 100 ° C, and pressed to obtain a negative electrode sheet having a thickness of 120 ⁇ m.
  • the polyamic acid solution was electrospun onto the prepared negative electrode sheet, the diameter of the needle was 0.2 mm, the spinning voltage was 100 volts, the distance from the needle to the negative electrode sheet was 25 cm, electrospinning was 0.2 hour, and then passed through 90°.
  • the amic acid is converted into a polyimide, and the heating temperature is maintained at 100 ° C for 2 hours, at 200 ° C for 2 hours, and at 250 ° C for 0.5 hour to obtain a lithium ion battery having a polyimide nanofiber membrane.
  • a composite negative electrode sheet was used.
  • the preparation method of the lithium ion battery is the same as that in the first embodiment.
  • the composite negative electrode sheet for a lithium ion battery is composed of a negative electrode sheet and a separator directly laminated on the surface of the negative electrode sheet, and the negative electrode sheet is composed of a current collector and a negative electrode active material coated on the surface of the current collector, and the separator is a polyimide nanofiber membrane.
  • the polyimide nanofiber membrane has a thickness of 5 ⁇ m.
  • the polyimide nanofiber membrane has a porosity of 50% and a pore diameter of 0.1 ⁇ m. Comparative example one
  • a mixture of negative active material artificial graphite, 3 g of binder styrene butadiene rubber (SBR) and 3 g of carboxymethylcellulose (CMC) was added to 200 g of water, and then stirred in a vacuum mixer to form a uniform slurry. .
  • the slurry was uniformly coated on both sides of a 9 ⁇ m copper foil, and the coated surface density was controlled to be 17.8 mg/cm 2 , and then dried at 100 ° C, and pressed to obtain a negative electrode sheet having a thickness of 120 ⁇ m.
  • the separator is made of commercial polyolefin separator Celgard 2400 (single-layer polypropylene film), and then the separator is wound with the positive and negative pole pieces. After assembly and encapsulation, the liquid is injected, sealed, and finally activated and tested for performance to obtain a lithium ion battery. .
  • the aqueous polymer colloidal emulsion is subjected to stepwise polymerization: 1000 parts of distilled water and 100 parts of polyethylidene pyrrolidone are added to a four-reaction reaction vessel of condensed water, and the reaction vessel is heated to 90 ° C, and stirred to dissolve until the material is transparent.
  • aqueous polymer colloidal emulsion was added to 15 parts of white carbon black and 100 parts of triethyl phosphate plasticizer, and ball-milled for 5 hours to prepare an aqueous polymer slurry.
  • the aqueous polymer slurry is coated on the prepared copper foil negative electrode sheet by a coating device, and the water and the plasticizer are volatilized by a hot air of 100 ° C and an infrared irradiation drying tunnel to obtain a polymer coating.
  • the composite negative electrode sheet and the positive electrode sheet for the lithium ion battery are assembled, packaged, injected, sealed, and finally activated and subjected to performance test to obtain a lithium ion battery.
  • the lithium ion batteries produced in the above examples and comparative examples were experimental batteries for the performance test of the following effect examples.
  • the test method is as follows: The lithium ion battery is charged to a 100% state of charge with a current of 1 C (1.6 A), and then charged to a constant voltage of 10 V for 2 hours with a current of 3 C (4.8 A) to observe whether the lithium ion battery is ignited or exploded.
  • the test method is as follows: The lithium ion battery is charged to a 100% state of charge with a current of 1 C (1.6 A), placed in an oven, and the oven temperature is raised from room temperature to 150 ° C at 5 ° C for 10 minutes without short circuit. In the case, continue to increase to 5 ° C to 180 ° C for 10 minutes, observe whether the lithium-ion battery is short-circuited. The lithium ion battery voltage drop greater than 0.2 volts is considered a short circuit.
  • the test method is as follows: Lithium-ion battery is charged to 100% charge state with 1C (1.6A) current, and a 2.7 mm diameter iron round nail penetrates the lithium ion battery body at a speed of 5 mm/sec, and the lithium ion is monitored. The temperature of the battery surface and whether it is a fire or explosion.
  • the test method is as follows: 1C (1.6A) current is charged to 4.2 volts, then constant voltage to current less than 80 mA, 1C (1.6A) current is discharged to 3.0 volts, thus repeating charge and discharge, and obtaining the 500th discharge capacity and initial The ratio of the initial discharge capacity.
  • the lithium ion battery prepared by using the composite negative electrode sheet for lithium ion battery of the embodiment of the invention has higher heat resistance, better safety performance and more safety than the lithium ion battery prepared by the comparative example. Good cycle performance.
  • the results are analyzed as follows:
  • the composite negative electrode sheet for a lithium ion battery is compounded with a polyimide nanofiber membrane, which can withstand high temperature thermal shock, and does not cause thermal runaway under internal partial short circuit conditions, and a composite negative electrode for a lithium ion battery.
  • the sheet does not generate tensile stress during the winding assembly process, and the internal resistance is not increased due to the deformation of the battery core during the cycle, so the cycle performance is better.

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Abstract

Provided are a composite negative electrode sheet for a lithium ion battery and a preparation method therefor and a lithium ion battery. The preparation method for a composite negative electrode sheet for a lithium ion battery comprises the steps of: spray-coating polyamic acid solution to the surface of a negative electrode sheet by way of electrostatic spinning, then performing mechanical rolling, and finally converting the polyamic acid spray-coated on the surface of the negative electrode sheet into polyimide by thermal imidization treatment to form a polyimide nano-fibre film on the surface of the negative electrode sheet, so as to obtain a composite negative electrode sheet for a lithium ion battery. The preparation method provided in the present invention simplifies the process in the prior art which requires separate preparation of a positive and negative electrode sheet and a separator followed by winding the separator with the positive and negative electrode sheet, and meanwhile, overcomes the problems of battery internal short circuit and deformation easily caused by wound arrangement of the separator and the positive and negative electrode sheet in the prior art. The lithium ion battery manufactured with the composite negative electrode sheet for a lithium ion battery in the present invention has excellent safety performance and a long service life, and can be used as high capacity and power batteries.

Description

一种锂离子电池用复合负极片及其制备方法和锂离子电池 本申请要求了 2012年 9月 24日提交中国专利局的, 申请号 201210356492.9, 发明名称为 "一种锂离子电池用复合负极片及其制备方法和锂离子电池"的中国 专利申请的优先权, 其全部内容通过引用结合在本申请中。 技术领域  Composite negative electrode sheet for lithium ion battery and preparation method thereof and lithium ion battery The application body is submitted to Chinese Patent Office on September 24, 2012, application number 201210356492.9, and the invention name is "a composite negative electrode sheet for lithium ion battery" The priority of the Chinese patent application and its preparation method and lithium ion battery are incorporated herein by reference. Technical field
本发明涉及锂离子电池领域, 特别是涉及一种锂离子电池用复合负极片及 其制备方法和锂离子电池。 背景技术  The present invention relates to the field of lithium ion batteries, and in particular to a composite negative electrode sheet for a lithium ion battery, a preparation method thereof and a lithium ion battery. Background technique
锂离子电池因具有质量轻、体积小、工作电压高、能量密度高、输出功率大、 充电效率高和无记忆效应等优点, 在手机、 笔记本电脑等领域得到了广泛的应 用。  Lithium-ion batteries have been widely used in mobile phones, notebook computers, etc. due to their advantages of light weight, small size, high operating voltage, high energy density, high output power, high charging efficiency and no memory effect.
锂离子电池通常由正极片、 负极片、 隔膜、 电解液和外壳组成。 其中, 隔 膜主要为市售的商业化的聚乙烯(PE )薄膜或聚丙烯(PP )薄膜,其厚度为 20〜40 μ ιη, 孔隙率在 40%左右, 隔膜间隔设置在正极片和负极片之间, 阻隔正负极极 片从而防止电池内部短路, 但允许离子流快速通过, 从而完成在电化学充放电 过程中锂离子在正负极极片之间的快速传输。  A lithium ion battery usually consists of a positive electrode sheet, a negative electrode sheet, a separator, an electrolyte, and an outer casing. Among them, the separator is mainly a commercially available commercial polyethylene (PE) film or a polypropylene (PP) film having a thickness of 20 to 40 μm, a porosity of about 40%, and a separator interval of the positive electrode and the negative electrode. Between the positive and negative pole pieces, the internal short circuit of the battery is prevented, but the ion current is allowed to pass quickly, thereby completing the rapid transfer of lithium ions between the positive and negative pole pieces during the electrochemical charging and discharging process.
现有锂离子电池的制备方法通常为先分别制备正极片、 负极片和隔膜, 然 后将隔膜与正负极极片卷绕, 经组装封装后注液、 密封, 最后活化并进行性能 检验。 但该制备方法中, 隔膜通常为轻软薄滑的薄膜, 在卷绕装配过程中与正 负极极片不易对齐, 往往易造成短路正负极极片之间的短路, 同时, 在卷绕装 配过程中易产生张力造成电芯变形, 并且随着循环次数的增多, 锂离子电池变 形情况还将加重, 容量衰减较大。 此外, 市售的商业化的聚乙烯薄膜或聚丙烯 薄膜等聚烯烃类薄膜的热稳定性较差, 导致锂离子电池存在安全隐患。 这是因 为, 锂离子电池的安全对策之一是使电流遮断, 即当锂离子电池内部温度较高 时, 具有多孔结构的聚合物隔膜应当能够产生熔化自动关闭多孔结构, 从而迅 速增加阻抗而使电流遮断。 但聚烯烃类薄膜的热稳定性较差, 聚乙烯薄膜的自 闭温度为 135〜140°C , 聚丙烯薄膜的自闭温度为 170°C左右, 易出现大量的体积 收缩使得隔膜面积收缩变小以及易完全被破坏而导致锂离子电池短路, 从而导 致电池***或着火。 The preparation method of the existing lithium ion battery is generally prepared by separately preparing a positive electrode sheet, a negative electrode sheet and a separator, and then winding the separator and the positive and negative electrode sheets, after being assembled and packaged, injecting and sealing, finally activating and performing performance test. However, in the preparation method, the separator is usually a light, soft and thin film, which is not easily aligned with the positive and negative pole pieces during the winding assembly process, and is often liable to cause short circuit between the positive and negative pole pieces, and at the same time, in the winding During the assembly process, tension is easily generated to cause the core to deform, and as the number of cycles increases, the lithium ion battery changes. The shape will also be aggravated and the capacity will be attenuated. In addition, polyolefin films such as commercially available polyethylene films or polypropylene films have poor thermal stability, which causes safety hazards in lithium ion batteries. This is because one of the safety measures for lithium-ion batteries is to interrupt the current, that is, when the internal temperature of the lithium-ion battery is high, the polymer membrane having a porous structure should be able to generate a melting to automatically close the porous structure, thereby rapidly increasing the impedance. Current interruption. However, the thermal stability of polyolefin film is poor. The self-closing temperature of polyethylene film is 135~140 °C, the self-closing temperature of polypropylene film is about 170 °C, and a large volume shrinkage is easy to cause the diaphragm area to shrink. Small and easily destroyed, causing a short circuit in the lithium-ion battery, causing the battery to explode or catch fire.
对此, 有人提出将隔膜与电极片复合在一起, 如公开号为 CN101246958A 无机氧化物, 直接涂覆在锂电池碳负极片上形成具有微孔涂层隔膜的复合电极 片, 再与正极片卷绕, 经组装封装后注液、 密封, 最后活化、 性能检验。 但该 制备方法制得的复合电极片中含有亲水性聚合物, 导致复合电极片极易吸水, 同时添加的无机氧化物具有较高的比表面积和较强的表面吸附能力, 也导致复 合电极的吸水, 严重影响了锂离子电池的循环性能, 另外无机氧化物颗粒进行 涂布过程中, 容易产生隔膜表面涂层不均匀 (颗粒不均匀, 分布也不均匀)等 现象, 以及, 锂离子电池在长期运行的过程中, 隔膜表面的无机颗粒涂层有脱 落的可能, 会导致锂离子电池性能下降。 发明内容  In this regard, it has been proposed to combine the separator with the electrode sheet, such as the inorganic oxide CN101246958A, which is directly coated on the carbon negative electrode sheet of the lithium battery to form a composite electrode sheet having a microporous coated separator, and then wound with the positive electrode sheet. , after assembly and encapsulation, injection, sealing, final activation, performance test. However, the composite electrode sheet prepared by the preparation method contains a hydrophilic polymer, which results in the composite electrode sheet being extremely easy to absorb water, and the added inorganic oxide has a high specific surface area and a strong surface adsorption capacity, and also results in a composite electrode. The water absorption, which seriously affects the cycle performance of the lithium ion battery, and in the coating process of the inorganic oxide particles, the surface coating of the separator is uneven (uneven particles, uneven distribution), and the lithium ion battery During the long-term operation, the inorganic particle coating on the surface of the separator may fall off, which may cause the performance of the lithium ion battery to decrease. Summary of the invention
有鉴于此,本发明实施例第一方面提供了一种锂离子电池用复合负极片,用 以解决现有技术中隔膜与正负极极片卷绕设置易引起的电池内部短路和电芯变 形的问题, 并且能够提高锂离子电池的安全性能和循环使用寿命。 本发明实施 例第二方面提供了该锂离子电池用复合负极片的制备方法。 本发明实施例第三 方面提供了包含该锂离子电池用复合负极片的锂离子电池。 In view of this, the first aspect of the embodiments of the present invention provides a composite negative electrode sheet for a lithium ion battery, which is used to solve the internal short circuit and the core deformation of the battery which are easily caused by the winding arrangement of the diaphragm and the positive and negative pole pieces in the prior art. The problem, and can improve the safety performance and cycle life of lithium-ion batteries. Implementation of the invention The second aspect provides a method for preparing the composite negative electrode sheet for a lithium ion battery. A third aspect of the present invention provides a lithium ion battery comprising the composite negative electrode sheet for a lithium ion battery.
第一方面,本发明实施例提供了一种锂离子电池用复合负极片,所述锂离子 电池用复合负极片由负极片和复合在所述负极片表面的隔膜组成, 所述负极片 由集流体和涂覆在集流体表面的负极活性材料组成, 所述隔膜为聚酰亚胺纳米 纤维膜。  In a first aspect, an embodiment of the present invention provides a composite negative electrode sheet for a lithium ion battery, wherein the composite negative electrode sheet for a lithium ion battery is composed of a negative electrode sheet and a separator composited on a surface of the negative electrode sheet, and the negative electrode sheet is assembled. The fluid is composed of a negative active material coated on a surface of the current collector, and the separator is a polyimide nanofiber membrane.
在本发明实施例第一方面中, 优选地, 聚酰亚胺纳米纤维膜的厚度为 5 μ m〜30 μ m。  In the first aspect of the embodiment of the present invention, preferably, the polyimide nanofiber film has a thickness of 5 μm to 30 μm.
优选地, 聚酰亚胺纳米纤维膜的孔隙率为 5%〜80%, 孔径为 Ο.ΟΙ μ η!〜 10 μ m。  Preferably, the polyimide nanofiber membrane has a porosity of 5% to 80% and a pore diameter of Ο.ΟΙ μ η! ~ 10 μ m.
优选地, 集流体为铜箔或铝箔。  Preferably, the current collector is a copper foil or an aluminum foil.
负极活性材料为任意可脱嵌锂离子的有机化合物或无机材料。  The negative electrode active material is any organic compound or inorganic material capable of deintercalating lithium ions.
本发明实施例第一方面克服了现有技术中隔膜与正负极极片卷绕设置易引 起的电池内部短路和电芯变形的问题, 同时, 隔膜为多孔高分子材料聚酰亚胺 纳米纤维膜, 耐热性能好, 并且能够提高锂离子电池的安全性能和循环使用寿 命, 因此适用于高容量和动力电池。  The first aspect of the embodiment of the present invention overcomes the problems of the internal short circuit and the deformation of the battery caused by the winding arrangement of the separator and the positive and negative pole pieces in the prior art. Meanwhile, the separator is a porous polymer material polyimide nanofiber. The film, which has good heat resistance and can improve the safety performance and cycle life of the lithium ion battery, is suitable for high capacity and power batteries.
第二方面, 本发明实施例提供了一种锂离子电池用复合负极片的制备方法, 包括以下步骤: 通过静电纺丝的方式将聚酰胺酸溶液喷涂在负极片表面, 然后 进行机械辊压, 最后热亚胺化处理将喷涂在负极片表面的聚酰胺酸转化为聚酰 亚胺, 在负极片表面形成聚酰亚胺纳米纤维膜, 得到锂离子电池用复合负极片。  In a second aspect, an embodiment of the present invention provides a method for preparing a composite negative electrode sheet for a lithium ion battery, comprising the steps of: spraying a polyamic acid solution on the surface of the negative electrode sheet by electrospinning, and then performing mechanical rolling, Finally, the thermal imidization treatment converts the polyamic acid sprayed on the surface of the negative electrode sheet into polyimide, and forms a polyimide nanofiber film on the surface of the negative electrode sheet to obtain a composite negative electrode sheet for a lithium ion battery.
在本发明实施例第二方面中, 优选地, 聚酰胺酸溶液按如下方法制备: 取二 元有机酸酐与有机二胺加入至有机溶剂中, 搅拌, 发生缩合反应制得聚酰胺酸 溶液。 更优选地, 二元有机酸酐为均苯四曱酸二酐 (PMDA)、 联苯四酸二酐 ( S-BPDA )、 异丙基二苯酐( IPDA )、 氧联苯四曱酸二酐( ODPA )、 二苯酮四 酸二酐(BTDA)和双酚 A二醚二酐(BPADA) 中的一种或几种。 In the second aspect of the present invention, preferably, the polyamic acid solution is prepared as follows: a dibasic organic acid anhydride and an organic diamine are added to an organic solvent, stirred, and a condensation reaction is carried out to obtain a polyamic acid solution. More preferably, the dibasic organic acid anhydride is pyromellitic acid dianhydride (PMDA), biphenyltetracarboxylic dianhydride (S-BPDA), isopropyl diphthalic anhydride (IPDA), oxybiphenyl tetraphthalic acid dianhydride ( One or more of ODPA), benzophenonetetracarboxylic dianhydride (BTDA) and bisphenol A diether dianhydride (BPADA).
更优选地, 有机二胺为 4,4-二氨基二苯醚(4,4-ODA)、 3,4-二氨基二苯醚 (3,4-ODA)、 间苯二胺 (MDA)、 对苯二胺 (PDA)、 3,3-二苯砜二胺 (3,3-SDA)、 联苯 二胺 (BPDA)和异丙基二苯胺 (IPDA)中的一种或几种。  More preferably, the organic diamine is 4,4-diaminodiphenyl ether (4,4-ODA), 3,4-diaminodiphenyl ether (3,4-ODA), m-phenylenediamine (MDA), One or more of p-phenylenediamine (PDA), 3,3-diphenylsulfone diamine (3,3-SDA), biphenyldiamine (BPDA), and isopropyldiphenylamine (IPDA).
更优选地, 有机溶剂为 Ν,Ν-二曱基曱酰胺 (DMF)、 Ν,Ν-二曱基乙酰胺 (DMAc)、 N-2-曱基吡咯烷酮 (NMP)、 四氢呋喃 (THF)和曱醇中的一种或几种。  More preferably, the organic solvent is hydrazine, hydrazine-dimercaptocarboxamide (DMF), hydrazine, hydrazine-dimercaptoacetamide (DMAc), N-2-mercaptopyrrolidone (NMP), tetrahydrofuran (THF) and hydrazine One or several of the alcohols.
更优选地, 二元有机酸酐与有机二胺按摩尔比为 0.7〜1.1:1, 有机溶剂的加 入量为二元有机酸酐和有机二胺总质量的 5〜8倍。  More preferably, the molar ratio of the dibasic organic acid anhydride to the organic diamine is 0.7 to 1.1:1, and the organic solvent is added in an amount of 5 to 8 times the total mass of the dibasic organic acid anhydride and the organic diamine.
更优选地, 搅拌过程的温度为 0°C〜30°C, 搅拌时间为 2〜10小时。  More preferably, the temperature of the stirring process is from 0 ° C to 30 ° C, and the stirring time is from 2 to 10 hours.
在本发明提供的第二个实施例中, 优选地, 静电纺丝的纺丝针头直径为 0.2 mm~ 1.5mm, 电压为 100v ~ 20kv, 针头与接收电极的距离为 10cm ~ 35cm, 纺 丝流量 0.2〜1毫升 /小时。  In a second embodiment provided by the present invention, preferably, the electrospun spinning needle has a diameter of 0.2 mm to 1.5 mm, a voltage of 100 v to 20 kV, and a distance between the needle and the receiving electrode of 10 cm to 35 cm, and a spinning flow rate. 0.2 to 1 ml / hour.
优选地, 机械辊压的强度为 1 ~ 15兆帕, 速度为 0.5〜1米 /分钟, 辊压时间 为 1 ~ 5分钟。  Preferably, the mechanical rolling has a strength of 1 to 15 MPa, a speed of 0.5 to 1 m/min, and a rolling time of 1 to 5 minutes.
优选地,热亚胺化处理是在氮气、氩气或真空下梯度升温,梯度升温为: 100 ~ 200°C保持 0.5 ~ 2小时, 200 ~ 250°C保持 0.5 ~ 2小时, 250 ~ 300°C保持 0.5 ~ 1.5 小时。  Preferably, the thermal imidization treatment is carried out by gradient heating under nitrogen, argon or vacuum, and the gradient heating is: 100 to 200 ° C for 0.5 to 2 hours, 200 to 250 ° C for 0.5 to 2 hours, 250 to 300 °. C is kept for 0.5 ~ 1.5 hours.
优选地, 聚酰亚胺纳米纤维膜的厚度为 5μηι〜30μηι。  Preferably, the thickness of the polyimide nanofiber film is 5 μηι to 30 μηι.
优选地, 聚酰亚胺纳米纤维膜的孔隙率为 5%〜80%, 孔径为 Ο.ΟΙ μη!〜 10μ m。  Preferably, the polyimide nanofiber membrane has a porosity of 5% to 80% and a pore diameter of Ο.ΟΙ μη! ~ 10μm.
负极片由集流体和涂覆在集流体表面的负极活性材料组成。 优选地, 集流体为铜箔或铝箔。 The negative electrode sheet is composed of a current collector and a negative electrode active material coated on the surface of the current collector. Preferably, the current collector is a copper foil or an aluminum foil.
负极活性材料为任意可脱嵌锂离子的有机化合物或无机材料。  The negative electrode active material is any organic compound or inorganic material capable of deintercalating lithium ions.
本发明实施例第二方面将隔膜直接复合在负极片上制得锂离子电池用复合 负极片, 简化了现有技术中需要先单独制备正、 负极片和隔膜且随后需要将隔 膜与正负极片进行卷绕的过程, 同时克服了现有技术中隔膜与正负极极片卷绕 设置易引起的电池内部短路和电芯变形的问题, 并且能够提高锂离子电池的安 全性能和循环使用寿命, 因此适用于高容量和动力电池。  In the second aspect of the present invention, the composite negative electrode sheet for a lithium ion battery is prepared by directly laminating the separator on the negative electrode sheet, which simplifies the preparation of the positive and negative electrode sheets and the separator separately in the prior art, and then the separator and the positive and negative electrode sheets are required. The winding process is carried out, and at the same time, the problems of internal short circuit and battery core deformation which are easily caused by the separator and the positive and negative pole piece winding arrangements in the prior art are overcome, and the safety performance and cycle life of the lithium ion battery can be improved. It is therefore suitable for high capacity and power batteries.
第三方面,本发明实施例提供了一种锂离子电池, 由锂离子电池用复合负极 片、 正极片、 非水电解液和外壳组成, 所述锂离子电池用复合负极片由负极片 和复合在所述负极片表面的隔膜组成, 所述负极片由集流体和涂覆在集流体表 面的负极活性材料组成, 所述隔膜为聚酰亚胺纳米纤维膜。  In a third aspect, an embodiment of the present invention provides a lithium ion battery, which is composed of a composite negative electrode sheet for a lithium ion battery, a positive electrode sheet, a nonaqueous electrolyte, and an outer casing, wherein the composite negative electrode sheet for the lithium ion battery is composed of a negative electrode sheet and a composite A separator composed of a separator on a surface of the negative electrode sheet, the negative electrode sheet being composed of a current collector and an anode active material coated on a surface of a current collector, the separator being a polyimide nanofiber membrane.
优选地, 聚酰亚胺纳米纤维膜的厚度为 5 μ ηι〜30 μ ηι。  Preferably, the polyimide nanofiber membrane has a thickness of 5 μηη to 30 μηη.
优选地, 聚酰亚胺纳米纤维膜的孔隙率为 5%〜80%, 孔径为 Ο.ΟΙ μ η!〜 10 μ m。  Preferably, the polyimide nanofiber membrane has a porosity of 5% to 80% and a pore diameter of Ο.ΟΙ μ η! ~ 10 μ m.
优选地, 集流体为铜箔或铝箔。  Preferably, the current collector is a copper foil or an aluminum foil.
负极活性材料为任意可脱嵌锂离子的有机化合物或无机材料。  The negative electrode active material is any organic compound or inorganic material capable of deintercalating lithium ions.
正极片由集流体和涂覆在集流体表面的正极活性材料组成,正极活性材料为 任意可脱嵌锂离子的有机化合物或无机材料。  The positive electrode sheet is composed of a current collector and a positive electrode active material coated on the surface of the current collector, and the positive electrode active material is an organic compound or an inorganic material which can deintercalate lithium ions.
优选地, 非水电解液是碳酸酯溶剂的电解液, 所述电解液中含有锂盐, 所述 碳酸酯选自碳酸亚乙酯 (EC ) 、 碳酸丙烯酯(PC ) 、 碳酸二曱酯(DMC )和碳 酸曱乙酯 ( EMC )中的一种或几种,所述锂盐选自 LiPF6、 LiBF4、 LiSbF6、 LiC104、 LiCF3S03、 LiA104、 LiAlCl4、 Li ( CF3S02 ) 2N、 LiBOB和 LiDFOB中的一种或 几种。 优选地, 外壳为铝塑膜、 钢壳、 铝壳或塑料壳。 Preferably, the non-aqueous electrolyte is an electrolyte of a carbonate solvent, and the electrolyte contains a lithium salt selected from the group consisting of ethylene carbonate (EC), propylene carbonate (PC), and dinonyl carbonate ( One or more of DMC) and cesium carbonate (EMC) selected from the group consisting of LiPF 6 , LiBF 4 , LiSbF 6 , LiC10 4 , LiCF 3 S0 3 , LiA10 4 , LiAlCl 4 , Li ( CF ) 3 S0 2 ) 2 One or more of N, LiBOB and LiDFOB. Preferably, the outer casing is an aluminum plastic film, a steel shell, an aluminum shell or a plastic shell.
本发明实施例第三方面中由于锂离子电池用复合负极片已复合有隔膜,无需 再另行设置隔膜也无需另行将隔膜与正负极片进行卷绕成型, 同时, 隔膜为多 孔高分子材料聚酰亚胺纳米纤维膜, 耐热性能好, 并且能够提高锂离子电池的 安全性能和循环使用寿命, 因此本发明实施例第三方面提供的锂离子电池易于 制备, 并且具有优良的安全性能以及长的使用寿命, 可用作高容量和动力电池。  In the third aspect of the embodiment of the present invention, since the composite negative electrode sheet for a lithium ion battery has been compounded with a separator, it is not necessary to separately provide a separator, and the separator and the positive and negative electrode sheets are not separately wound, and the separator is a porous polymer material. The imide nanofiber membrane has good heat resistance and can improve the safety performance and cycle life of the lithium ion battery. Therefore, the lithium ion battery provided by the third aspect of the embodiment of the invention is easy to prepare, and has excellent safety performance and long The service life can be used as a high capacity and power battery.
本发明实施例的优点将会在下面的说明书中部分阐明,一部分根据说明书是 显而易见的, 或者可以通过本发明实施例的实施而获知。 附图说明  The advantages of the embodiments of the present invention will be set forth in part in the description which follows. DRAWINGS
图 1 为本发明具体实施方式中锂离子电池用复合负极片的制备方法的流程 图。 具体实施方式 以下所述是本发明实施例的优选实施方式, 应当指出, 对于本技术领域的 普通技术人员来说, 在不脱离本发明实施例原理的前提下, 还可以做出若干改 进和润饰, 这些改进和润饰也视为本发明实施例的保护范围。  BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a flow chart showing a method of preparing a composite negative electrode sheet for a lithium ion battery according to an embodiment of the present invention. The following is a preferred embodiment of the embodiments of the present invention. It should be noted that those skilled in the art can make some improvements and refinements without departing from the principles of the embodiments of the present invention. These improvements and retouchings are also considered to be the scope of protection of the embodiments of the present invention.
本发明实施例第一方面提供了一种锂离子电池用复合负极片,用以解决现有 技术中隔膜与正负极极片卷绕设置易引起的电池内部短路和电芯变形的问题, 并且能够提高锂离子电池的安全性能和循环使用寿命。 本发明实施例第二方面 提供了该锂离子电池用复合负极片的制备方法。 本发明实施例第三方面提供了 包含该锂离子电池用复合负极片的锂离子电池。  The first aspect of the embodiments of the present invention provides a composite negative electrode sheet for a lithium ion battery, which solves the problems of internal short circuit and battery core deformation caused by the separator and the positive and negative pole piece winding arrangements in the prior art, and Improves the safety and cycle life of lithium-ion batteries. A second aspect of the present invention provides a method for preparing the composite negative electrode sheet for a lithium ion battery. A third aspect of the present invention provides a lithium ion battery comprising the composite negative electrode sheet for a lithium ion battery.
第一方面,本发明实施例提供了一种锂离子电池用复合负极片,所述锂离子 电池用复合负极片由负极片和复合在所述负极片表面的隔膜组成, 所述负极片 由集流体和涂覆在集流体表面的负极活性材料组成, 所述隔膜为聚酰亚胺纳米 纤维膜。 In a first aspect, an embodiment of the present invention provides a composite negative electrode sheet for a lithium ion battery, wherein the composite negative electrode sheet for a lithium ion battery is composed of a negative electrode sheet and a separator composited on a surface of the negative electrode sheet, and the negative electrode sheet The current collector is composed of a current collector and an anode active material coated on the surface of the current collector, and the separator is a polyimide nanofiber membrane.
在本发明实施例第一方面中, 聚酰亚胺纳米纤维膜的厚度为 5 μ ηι〜30 μ ηι。 聚酰亚胺纳米纤维膜较薄, 用于制备锂离子电池时占据电池内部空间较小, 因 此可提高锂离子电池的容量密度。  In the first aspect of the embodiment of the present invention, the polyimide nanofiber film has a thickness of 5 μηη to 30 μηη. The polyimide nanofiber membrane is thinner and takes up less space inside the battery when used for preparing a lithium ion battery, thereby increasing the capacity density of the lithium ion battery.
孔隙率涉及单位面积上孔的数量的多少,孔径的大小涉及离子在其中穿梭的 能力。 聚酰亚胺纳米纤维膜的孔隙率为 5%〜80%, 孔径为 Ο.ΟΙ μ η!〜 10 μ ιη。 此 时, 离子流可快速通过, 从而完成在电化学充放电过程中锂离子在正负极极片 之间的快速传输。  Porosity relates to the number of holes per unit area, and the size of the pores relates to the ability of ions to shuttle therethrough. The polyimide nanofiber membrane has a porosity of 5% to 80% and a pore diameter of Ο.ΟΙ μ η! ~ 10 μ ιη. At this time, the ion current can be quickly passed, thereby completing the rapid transfer of lithium ions between the positive and negative pole pieces during electrochemical charging and discharging.
集流体为铜箔或铝箔。  The current collector is copper foil or aluminum foil.
负极活性材料为任意可脱嵌锂离子的有机化合物或无机材料, 例如碳材料。 本发明实施例第一方面克服了现有技术中隔膜与正负极极片卷绕设置易引 起的电池内部短路和电芯变形的问题, 同时, 隔膜为多孔高分子材料聚酰亚胺 纳米纤维膜, 耐热性能好, 并且能够提高锂离子电池的安全性能和循环使用寿 命, 因此适用于高容量和动力电池。  The negative electrode active material is any organic compound or inorganic material capable of deintercalating lithium ions, such as a carbon material. The first aspect of the embodiment of the present invention overcomes the problems of the internal short circuit and the deformation of the battery caused by the winding arrangement of the separator and the positive and negative pole pieces in the prior art. Meanwhile, the separator is a porous polymer material polyimide nanofiber. The film, which has good heat resistance and can improve the safety performance and cycle life of the lithium ion battery, is suitable for high capacity and power batteries.
第二方面, 本发明实施例提供了一种锂离子电池用复合负极片的制备方法, 如图 1 所示, 包括以下步骤: 通过静电纺丝的方式将聚酰胺酸溶液喷涂在负极 片表面, 然后进行机械辊压, 最后热亚胺化处理将喷涂在负极片表面的聚酰胺 酸转化为聚酰亚胺, 在负极片表面形成聚酰亚胺纳米纤维膜, 得到锂离子电池 用复合负极片。  In a second aspect, an embodiment of the present invention provides a method for preparing a composite negative electrode sheet for a lithium ion battery. As shown in FIG. 1 , the method includes the following steps: spraying a polyamic acid solution on the surface of the negative electrode sheet by electrospinning. Then, mechanical rolling is performed, and finally, the thermal imidization treatment converts the polyamic acid sprayed on the surface of the negative electrode sheet into polyimide, and forms a polyimide nanofiber film on the surface of the negative electrode sheet to obtain a composite negative electrode sheet for a lithium ion battery. .
在本发明实施例第二方面中, 聚酰胺酸溶液按如下方法制备:取二元有机酸 酐与有机二胺加入至有机溶剂中, 搅拌, 发生缩合反应制得聚酰胺酸溶液。  In the second aspect of the present invention, the polyamic acid solution is prepared by adding a dibasic organic acid anhydride and an organic diamine to an organic solvent, stirring, and a condensation reaction to obtain a polyamic acid solution.
二元有机酸酐为均苯四曱 S史二酐( PMDA )、 联苯四酸二酐( S-BPDA )、 异 丙基二苯酐( IPDA )、 氧联苯四曱酸二肝 ( ODPA )、 二苯酮四酸二酐( BTDA ) 和双酚 A二醚二酐(BPADA ) 中的一种或几种。 The dibasic organic acid anhydride is benzoic acid succinic anhydride (PMDA), biphenyltetracarboxylic dianhydride (S-BPDA), and One or more of propyl diphenyl anhydride ( IPDA ), oxydiphenyltetradecanoic acid (ODPA), benzophenone tetraacid dianhydride (BTDA), and bisphenol A diether dianhydride (BPADA).
有机二胺为 4,4-二氨基二苯醚(4,4-ODA )、 3,4-二氨基二苯醚(3,4-00入)、 间苯二胺 (MDA)、 对苯二胺 (PDA)、 3,3-二苯砜二胺 (3,3-SDA)、联苯二胺 (BPDA) 和异丙基二苯胺 (IPDA)中的一种或几种。  The organic diamine is 4,4-diaminodiphenyl ether (4,4-ODA), 3,4-diaminodiphenyl ether (3,4-00%), m-phenylenediamine (MDA), p-phenylene One or more of amine (PDA), 3,3-diphenylsulfone diamine (3,3-SDA), biphenyldiamine (BPDA), and isopropyldiphenylamine (IPDA).
有机溶剂为 Ν,Ν-二曱基曱酰胺 (DMF)、 Ν,Ν-二曱基乙酰胺 (DMAc)、 N-2-曱 基吡咯烷酮 (NMP)、 四氢呋喃 (THF)和曱醇中的一种或几种。  The organic solvent is one of hydrazine, hydrazine-dimercaptocarboxamide (DMF), hydrazine, hydrazine-dimercaptoacetamide (DMAc), N-2-mercaptopyrrolidone (NMP), tetrahydrofuran (THF) and decyl alcohol. Kind or several.
二元有机酸酐与有机二胺按摩尔比为 0.7〜1.1: 1 , 有机溶剂的加入量为二元 有机酸酐和有机二胺总质量的 5〜8倍。  The molar ratio of the dibasic organic acid anhydride to the organic diamine is 0.7 to 1.1:1, and the organic solvent is added in an amount of 5 to 8 times the total mass of the dibasic organic acid anhydride and the organic diamine.
搅拌过程的温度为 0°C〜30°C , 搅拌时间为 2〜10小时。  The temperature of the stirring process is 0 ° C to 30 ° C, and the stirring time is 2 to 10 hours.
在本发明提供的第二个实施例中, 静电纺丝的纺丝针头直径为 0.2 mm ~ 1.5mm, 电压为 100v ~ 20kv, 针头与接受电极的距离为 10cm ~ 35cm, 纺丝流量 0.2〜1毫升 /小时。  In the second embodiment provided by the present invention, the spinning needle of the electrospinning has a diameter of 0.2 mm to 1.5 mm, a voltage of 100 v to 20 kV, a distance between the needle and the receiving electrode of 10 cm to 35 cm, and a spinning flow rate of 0.2 to 1 ML/hr.
机械辊压的强度为 1 ~ 15兆帕, 速度为 0.5〜1米 /分钟, 辊压时间为 1 ~ 5分 钟。  The mechanical rolling strength is 1 to 15 MPa, the speed is 0.5 to 1 m / min, and the rolling time is 1 to 5 minutes.
热亚胺化处理是在氮气、 氩气或真空下梯度升温, 梯度升温为: 100 ~ 200°C 保持 0.5 ~ 2小时, 200 ~ 250°C保持 0.5 ~ 2小时, 250 ~ 300°C保持 0.5 ~ 1.5小时。  The thermal imidization treatment is carried out by gradient heating under nitrogen, argon or vacuum. The gradient temperature is: 100 ~ 200 °C for 0.5 ~ 2 hours, 200 ~ 250 °C for 0.5 ~ 2 hours, 250 ~ 300 °C for 0.5. ~ 1.5 hours.
聚酰亚胺纳米纤维膜的厚度为 5 μ m〜30 μ m。  The polyimide nanofiber membrane has a thickness of 5 μm to 30 μm.
聚酰亚胺纳米纤维膜的孔隙率为 5%〜80%, 孔径为 0.01 μ η!〜 10 μ ιη。  The polyimide nanofiber membrane has a porosity of 5% to 80% and a pore diameter of 0.01 μ η! ~ 10 μ ιη.
负极片由集流体和涂覆在集流体表面的负极活性材料组成。  The negative electrode sheet is composed of a current collector and a negative electrode active material coated on the surface of the current collector.
集流体为铜箔或铝箔。  The current collector is copper foil or aluminum foil.
负极活性材料为任意可脱嵌锂离子的有机化合物或无机材料。  The negative electrode active material is any organic compound or inorganic material capable of deintercalating lithium ions.
本发明实施例第二方面将隔膜直接复合在负极片上制得锂离子电池用复合 负极片, 简化了现有技术中需要先单独制备正、 负极片和隔膜且随后需要将隔 膜与正负极片进行卷绕的过程, 同时克服了现有技术中隔膜与正负极极片卷绕 设置易引起的电池内部短路和电芯变形的问题, 并且能够提高锂离子电池的安 全性能和循环使用寿命, 因此适用于高容量和动力电池。 In the second aspect of the embodiment of the present invention, the separator is directly composited on the negative electrode sheet to prepare a composite for a lithium ion battery. The negative electrode sheet simplifies the prior art process of separately preparing the positive and negative electrode sheets and the separator and then needs to wind the separator and the positive and negative electrode sheets, while overcoming the prior art diaphragm and positive and negative pole coils. It is easy to solve the problem of internal short circuit of the battery and deformation of the battery core, and can improve the safety performance and cycle life of the lithium ion battery, and thus is suitable for high capacity and power batteries.
第三方面,本发明实施例提供了一种锂离子电池, 由锂离子电池用复合负极 片、 正极片、 非水电解液和外壳组成, 所述锂离子电池用复合负极片由负极片 和复合在所述负极片表面的隔膜组成, 所述负极片由集流体和涂覆在集流体表 面的负极活性材料组成, 所述隔膜为聚酰亚胺纳米纤维膜。  In a third aspect, an embodiment of the present invention provides a lithium ion battery, which is composed of a composite negative electrode sheet for a lithium ion battery, a positive electrode sheet, a nonaqueous electrolyte, and an outer casing, wherein the composite negative electrode sheet for the lithium ion battery is composed of a negative electrode sheet and a composite A separator composed of a separator on a surface of the negative electrode sheet, the negative electrode sheet being composed of a current collector and an anode active material coated on a surface of a current collector, the separator being a polyimide nanofiber membrane.
聚酰亚胺纳米纤维膜的厚度为 5 μ m〜30 μ m。  The polyimide nanofiber membrane has a thickness of 5 μm to 30 μm.
聚酰亚胺纳米纤维膜的孔隙率为 5%〜80%, 孔径为 0.01 μ η!〜 10 μ ιη。  The polyimide nanofiber membrane has a porosity of 5% to 80% and a pore diameter of 0.01 μ η! ~ 10 μ ιη.
集流体为铜箔或铝箔。  The current collector is copper foil or aluminum foil.
负极活性材料为任意可脱嵌锂离子的有机化合物或无机材料。  The negative electrode active material is any organic compound or inorganic material capable of deintercalating lithium ions.
正极片由集流体和涂覆在集流体表面的正极活性材料组成,正极活性材料为 任意可脱嵌锂离子的有机化合物或无机材料。  The positive electrode sheet is composed of a current collector and a positive electrode active material coated on the surface of the current collector, and the positive electrode active material is an organic compound or an inorganic material which can deintercalate lithium ions.
非水电解液是碳酸酯溶剂的电解液,所述电解液中含有锂盐,所述碳酸酯选 自碳酸亚乙酯 (EC ) 、 碳酸丙烯酯(PC ) 、 碳酸二曱酯(DMC )和碳酸曱乙酯 ( EMC )中的一种或几种 ,所述锂盐选自 LiPF6、 LiBF4、 LiSbF6、 LiC104、 LiCF3S03、 LiA104、 LiAlCl4、 Li ( CF3S02 ) 2N、 LiBOB和 LiDFOB中的一种或几种。 The nonaqueous electrolyte is an electrolyte of a carbonate solvent containing a lithium salt selected from the group consisting of ethylene carbonate (EC), propylene carbonate (PC), dinonyl carbonate (DMC), and One or more of ethyl lanthanum carbonate (EMC) selected from the group consisting of LiPF 6 , LiBF 4 , LiSbF 6 , LiC10 4 , LiCF 3 S0 3 , LiA10 4 , LiAlCl 4 , Li ( CF 3 S0 2 One or more of 2 N, LiBOB and LiDFOB.
外壳为铝塑膜、 钢壳、 铝壳或塑料壳。  The outer casing is an aluminum plastic film, a steel shell, an aluminum shell or a plastic shell.
锂离子电池的制作  Production of lithium ion battery
将锂离子电池用复合负极片和正极片裁切至一定尺寸,然后将锂离子电池用 复合负极片和正极片卷绕好用铝塑膜预封, 制得 423485方型电池极芯, 随后完 成方形卷绕软包电池, 最后注入非水电解液, 即制得锂离子电池。 本发明实施例第三方面中由于锂离子电池用复合负极片已复合有隔膜,无需 再另行设置隔膜也无需另行将隔膜与正负极片进行卷绕成型, 同时, 隔膜为多 孔高分子材料聚酰亚胺纳米纤维膜, 耐热性能好, 并且能够提高锂离子电池的 安全性能和循环使用寿命, 因此本发明实施例第三方面提供的锂离子电池易于 制备, 并且具有优良的安全性能以及长的使用寿命, 可用作高容量和动力电池。 The composite negative electrode sheet and the positive electrode sheet for the lithium ion battery are cut to a certain size, and then the composite negative electrode sheet and the positive electrode sheet for the lithium ion battery are wound and pre-sealed with an aluminum plastic film to obtain a 423485 square type battery core, which is then completed. The square-wound soft-packed battery is finally filled with a non-aqueous electrolyte to produce a lithium-ion battery. In the third aspect of the embodiment of the present invention, since the composite negative electrode sheet for a lithium ion battery has been compounded with a separator, it is not necessary to separately provide a separator, and the separator and the positive and negative electrode sheets are not separately wound, and the separator is a porous polymer material. The imide nanofiber membrane has good heat resistance and can improve the safety performance and cycle life of the lithium ion battery. Therefore, the lithium ion battery provided by the third aspect of the embodiment of the invention is easy to prepare, and has excellent safety performance and long The service life can be used as a high capacity and power battery.
下面以方形卷绕式锂离子软包电池(型号为 423485 ) 的制作和测试为例, 分多个实施例对本发明实施例进行进一步的说明。 其中, 本发明实施例不限定 于以下的具体实施例。 在不变主权利的范围内, 可以适当的进行变更实施。  The following is a description of the embodiments of the present invention in a plurality of embodiments, taking the fabrication and testing of a square-wound lithium-ion soft pack battery (model 423485) as an example. The embodiments of the present invention are not limited to the specific embodiments below. Changes can be implemented as appropriate within the scope of the invariable principal rights.
实施例一  Embodiment 1
锂离子电池用复合负极片的制备方法, 包括如下步骤:  The preparation method of the composite negative electrode sheet for a lithium ion battery comprises the following steps:
( 1 )聚酰胺酸溶液的合成  (1) Synthesis of polyamic acid solution
将 45克均苯四曱酸二酐(PMDA )、 42克二氨基二苯醚 (ODA)加入到搅拌 桶, 加入 500毫升 Ν,Ν-二曱基曱酰胺 (DMF), 然后在 30 °C温度下搅拌反应 2小 时, 发生缩合反应得到均一的聚酰胺酸溶液。  Add 45 g of pyromellitic dianhydride (PMDA), 42 g of diaminodiphenyl ether (ODA) to the mixing tank, add 500 ml of hydrazine, hydrazine-dihydrazinamide (DMF), then at 30 °C. The reaction was stirred at a temperature for 2 hours, and a condensation reaction occurred to obtain a uniform polyamic acid solution.
( 2 ) 负极片制备  (2) Preparation of negative electrode sheets
将 200克负极活性物质人造石墨、 3克粘结剂丁苯橡胶 (SBR)和 3克羧曱基 纤维素 (CMC)的混合物加入到 200克水中,然后在真空搅拌机中搅拌形成均匀的 浆料。 将该浆料均匀地涂布在 9微米的铜箔的两面, 控制涂布的面密度为 17.8 毫克 /平方厘米, 然后在 100°C下烘干, 辊压制得厚度为 120微米的负极片。  200 g of a mixture of negative active material artificial graphite, 3 g of binder styrene butadiene rubber (SBR) and 3 g of carboxymethylcellulose (CMC) was added to 200 g of water, and then stirred in a vacuum mixer to form a uniform slurry. . The slurry was uniformly coated on both sides of a 9 μm copper foil, and the coated surface density was controlled to be 17.8 mg/cm 2 , and then dried at 100 ° C, and pressed to obtain a negative electrode sheet having a thickness of 120 μm.
( 3 )锂离子电池用复合负极片制备  (3) Preparation of composite negative electrode sheets for lithium ion batteries
将聚酰胺酸溶液进行静电纺丝到已制备好的负极片上, 针头直径为 1.5 毫 米, 纺丝电压为 20千伏, 针头到负极片的距离为 18厘米, 电纺丝 1小时, 然 后经过 90°C烘箱预烘干, 再经过辊压机辊压, 压强为 15兆帕, 速度为 0.5米 / 分钟, 辊压 5分钟, 控制聚酰胺酸纳米纤维膜厚度为 30 μ ηι, 在氮气气氛下加 热将聚酰胺酸转化为聚酰亚胺, 加热的温度为 200°C下保持 0.5小时, 250°C下 保持 0.5小时, 300°C下保持 0.5小时, 得到具有聚酰亚胺纳米纤维膜的锂离子 电池用复合负极片。 The polyamic acid solution was electrospun onto a prepared negative electrode sheet having a needle diameter of 1.5 mm, a spinning voltage of 20 kV, a needle to negative electrode sheet distance of 18 cm, electrospinning for 1 hour, and then passing through 90 °C oven pre-drying, and then rolling through the roller press, the pressure is 15 MPa, the speed is 0.5 m / Minutes, rolling for 5 minutes, controlling the thickness of the polyamic acid nanofiber film to 30 μηη, heating the polyamic acid to polyimide under heating in a nitrogen atmosphere, and maintaining the heating temperature at 200 ° C for 0.5 hour, 250 ° The mixture was kept at 0.5 hour for 0.5 hour and at 350 ° C for 0.5 hour to obtain a composite negative electrode sheet for a lithium ion battery having a polyimide nanofiber film.
本实施例制得的锂离子电池用复合负极片,由负极片和直接复合在负极片表 面的隔膜组成, 负极片由集流体和涂覆在集流体表面的负极活性材料组成, 隔 膜为聚酰亚胺纳米纤维膜。 聚酰亚胺纳米纤维膜的厚度为 30 μ ιη。 聚酰亚胺纳 米纤维膜的孔隙率为 70%, 孔径为 10 μ ιη。  The composite negative electrode sheet for a lithium ion battery prepared in this embodiment is composed of a negative electrode sheet and a separator directly laminated on the surface of the negative electrode sheet, and the negative electrode sheet is composed of a current collector and a negative electrode active material coated on the surface of the current collector, and the separator is a polyacyl group. Imine nanofiber membrane. The polyimide nanofiber membrane has a thickness of 30 μm. The polyimide nanofiber membrane has a porosity of 70% and a pore diameter of 10 μm.
锂离子电池的制备方法  Method for preparing lithium ion battery
将实施例一制得的锂离子电池用复合负极片裁切至尺寸为 405毫米 Χ80毫 米, 其中含有 5.3克活性成份人造石墨。  The composite negative electrode sheet for a lithium ion battery obtained in Example 1 was cut to a size of 405 mm Χ 80 mm, which contained 5.3 g of active ingredient artificial graphite.
将 200克正极活性物质 LiCo02、 4克粘结剂聚偏二氟乙烯 (PVDF)、 6克导 电剂乙炔黑的混合物加入到 40克 N-曱基 - 2吡咯烷酮 (NMP)中, 然后在真空搅 拌机中搅拌形成均勾的正极浆料。 将该浆料均勾的涂布在 16微米的铝箔上, 控 制涂布的面密度为 34毫克 /平方厘米, 然后 120°C下烘干、 辊压、 裁切为 392毫 米 X78毫米的正极片, 其中含有 11.5克活性成份 LiCo02Adding a mixture of 200 g of the positive active material LiCo0 2 , 4 g of the binder polyvinylidene fluoride (PVDF), and 6 g of the conductive agent acetylene black to 40 g of N-fluorenyl-2-pyrrolidone (NMP), followed by vacuum The mixture was stirred in a mixer to form a positive electrode slurry. The slurry was uniformly coated on a 16 micron aluminum foil to control the coated areal density of 34 mg/cm 2 , and then dried, rolled, and cut into a positive film of 392 mm X 78 mm at 120 ° C. It contains 11.5 g of active ingredient LiCo0 2 .
将上述裁切至一定形状的锂离子电池用复合负极片、 正极片卷绕好用铝塑 膜预封, 制得 423485方型电池极芯, 随后完成方形卷绕软包电池, 最后注入非 水电解液 5克, 所述非水电解液为碳酸亚乙酯: 曱基乙基碳酸酯: 碳酸二乙酯 体积比为 1 : 1 : 1形成的混合溶液, 其中含有 1摩尔的六氟磷酸锂, 即制得锂 离子电池, 该锂离子电池的设计容量为 1600毫安时。  The composite negative electrode sheet and the positive electrode sheet for lithium ion battery cut into a certain shape are pre-sealed by aluminum plastic film to obtain a 423485 square type battery core, and then the square-wound soft-pack battery is completed, and finally the non-water is injected. 5 g of electrolyte, the non-aqueous electrolyte is ethylene carbonate: mercaptoethyl carbonate: a mixed solution of diethyl carbonate in a volume ratio of 1:1:1, containing 1 mol of lithium hexafluorophosphate, A lithium ion battery has a design capacity of 1600 mAh.
实施例二  Embodiment 2
锂离子电池用复合负极片的制备方法, 包括如下步骤: ( 1 )聚酰胺酸溶液的合成 The preparation method of the composite negative electrode sheet for a lithium ion battery comprises the following steps: (1) Synthesis of polyamic acid solution
将 45克异丙基二苯酐、 42克二苯砜二胺加入到搅拌桶,加入 500毫升 Ν,Ν- 二曱基乙酰胺 (DMAc), 然后在 10°C温度下搅拌反应 8小时, 发生缩合反应得到 均一的聚酰胺酸溶液。  45 g of isopropyl diphenyl anhydride and 42 g of diphenyl sulfone diamine were added to a mixing tank, 500 ml of hydrazine, hydrazine-dimercaptoacetamide (DMAc) was added, and then the reaction was stirred at 10 ° C for 8 hours. The condensation reaction gives a homogeneous polyamic acid solution.
( 2 ) 负极片制备  (2) Preparation of negative electrode sheets
将 200克负极活性物质人造石墨、 3克粘结剂丁苯橡胶 (SBR)和 3克羧曱基 纤维素 (CMC)的混合物加入到 200克水中,然后在真空搅拌机中搅拌形成均匀的 浆料。 将该浆料均匀地涂布在 9微米的铜箔的两面, 控制涂布的面密度为 17.8 毫克 /平方厘米, 然后在 100°C下烘干, 辊压制得厚度为 120微米的负极片。  200 g of a mixture of negative active material artificial graphite, 3 g of binder styrene butadiene rubber (SBR) and 3 g of carboxymethylcellulose (CMC) was added to 200 g of water, and then stirred in a vacuum mixer to form a uniform slurry. . The slurry was uniformly coated on both sides of a 9 μm copper foil, and the coated surface density was controlled to be 17.8 mg/cm 2 , and then dried at 100 ° C, and pressed to obtain a negative electrode sheet having a thickness of 120 μm.
( 3 )锂离子电池用复合负极片制备  (3) Preparation of composite negative electrode sheets for lithium ion batteries
将聚酰胺酸溶液进行静电纺丝到已制备好的负极片上, 针头直径为 1毫米, 纺丝电压为 1000伏, 针头到负极片的距离为 20厘米, 电纺丝 0.8小时, 然后经 过 90°C烘箱预烘干, 再经过辊压机辊压, 压强为 5兆帕, 速度为 0.8米 /分钟, 辊压 3分钟, 控制聚酰胺酸纳米纤维膜厚度为 15微米, 在氩气气氛下加热将聚 酰胺酸转化为聚酰亚胺, 加热的温度为 150°C下保持 1小时, 220°C下保持 1小 时, 300°C下保持 1小时, 得到具有聚酰亚胺纳米纤维膜的锂离子电池用复合负 极片。  The polyamic acid solution was electrospun onto the prepared negative electrode sheet, the needle diameter was 1 mm, the spinning voltage was 1000 volts, the distance from the needle to the negative electrode sheet was 20 cm, electrospinning was 0.8 hour, and then passed through 90°. The C oven is pre-baked and then rolled by a roller press at a pressure of 5 MPa, a speed of 0.8 m/min, and a rolling pressure of 3 minutes. The polyamic acid nanofiber film is controlled to have a thickness of 15 μm and heated under an argon atmosphere. The polyamic acid is converted into a polyimide, and the heating temperature is maintained at 150 ° C for 1 hour, at 220 ° C for 1 hour, and at 300 ° C for 1 hour to obtain lithium having a polyimide nanofiber membrane. Composite negative electrode sheet for ion batteries.
锂离子电池用复合负极片, 由负极片和直接复合在负极片表面的隔膜组成, 负极片由集流体和涂覆在集流体表面的负极活性材料组成, 隔膜为聚酰亚胺纳 米纤维膜。 聚酰亚胺纳米纤维膜的厚度为 15 μ ιη。 聚酰亚胺纳米纤维膜的孔隙 率为 60%, 孔径为 1 μ ιη。  The composite negative electrode sheet for a lithium ion battery is composed of a negative electrode sheet and a separator directly laminated on the surface of the negative electrode sheet, and the negative electrode sheet is composed of a current collector and a negative electrode active material coated on the surface of the current collector, and the separator is a polyimide nanofiber membrane. The polyimide nanofiber membrane has a thickness of 15 μm. The polyimide nanofiber membrane has a porosity of 60% and a pore diameter of 1 μm.
锂离子电池的制备方法同实施例一。  The preparation method of the lithium ion battery is the same as that in the first embodiment.
实施例三 锂离子电池用复合负极片的制备方法, 包括如下步骤: Embodiment 3 The preparation method of the composite negative electrode sheet for a lithium ion battery comprises the following steps:
( 1 )聚酰胺酸溶液的合成  (1) Synthesis of polyamic acid solution
将 45克异丙基二苯酐、 24克对苯二胺加入到搅拌桶, 加入 450毫升 Ν,Ν- 二曱基乙酰胺 (DMAc), 然后在 0°C温度下搅拌反应 10小时, 发生缩合反应得到 均一的聚酰胺酸溶液。  45 g of isopropyl phthalic anhydride and 24 g of p-phenylenediamine were added to a mixing tank, 450 ml of hydrazine, hydrazine-dimercaptoacetamide (DMAc) was added, and then the reaction was stirred at 0 ° C for 10 hours to cause condensation. The reaction gave a homogeneous solution of the polyamic acid.
( 2 ) 负极片制备  (2) Preparation of negative electrode sheets
将 200克负极活性物质人造石墨、 3克粘结剂丁苯橡胶 (SBR)和 3克羧曱基 纤维素 (CMC)的混合物加入到 200克水中,然后在真空搅拌机中搅拌形成均匀的 浆料。 将该浆料均匀地涂布在 9微米的铜箔的两面, 控制涂布的面密度为 17.8 毫克 /平方厘米, 然后在 100°C下烘干, 辊压制得厚度为 120微米的负极片。  200 g of a mixture of negative active material artificial graphite, 3 g of binder styrene butadiene rubber (SBR) and 3 g of carboxymethylcellulose (CMC) was added to 200 g of water, and then stirred in a vacuum mixer to form a uniform slurry. . The slurry was uniformly coated on both sides of a 9 μm copper foil, and the coated surface density was controlled to be 17.8 mg/cm 2 , and then dried at 100 ° C, and pressed to obtain a negative electrode sheet having a thickness of 120 μm.
( 3 )锂离子电池用复合负极片制备  (3) Preparation of composite negative electrode sheets for lithium ion batteries
将聚酰胺酸溶液进行静电纺丝到已制备好的负极片上, 针头直径为 0.2 毫 米, 纺丝电压为 100伏, 针头到负极片的距离为 25厘米, 电纺丝 0.2小时, 然 后经过 90°C烘箱预烘干,再经过辊压机辊压,压强为 3兆帕,速度为 1米 /分钟, 辊压 1分钟, 控制聚酰胺酸纳米纤维膜厚度为 5微米, 在真空下加热将聚酰胺 酸转化为聚酰亚胺, 加热的温度为 100°C下保持 2小时, 200°C下保持 2小时, 250°C下保持 0.5小时, 得到具有聚酰亚胺纳米纤维膜的锂离子电池用复合负极 片。  The polyamic acid solution was electrospun onto the prepared negative electrode sheet, the diameter of the needle was 0.2 mm, the spinning voltage was 100 volts, the distance from the needle to the negative electrode sheet was 25 cm, electrospinning was 0.2 hour, and then passed through 90°. C oven pre-drying, and then rolling through a roller press, the pressure is 3 MPa, the speed is 1 m / min, rolling for 1 minute, controlling the thickness of the polyamic acid nanofiber film to 5 microns, heating under vacuum The amic acid is converted into a polyimide, and the heating temperature is maintained at 100 ° C for 2 hours, at 200 ° C for 2 hours, and at 250 ° C for 0.5 hour to obtain a lithium ion battery having a polyimide nanofiber membrane. A composite negative electrode sheet was used.
锂离子电池的制备方法同实施例一。  The preparation method of the lithium ion battery is the same as that in the first embodiment.
锂离子电池用复合负极片, 由负极片和直接复合在负极片表面的隔膜组成, 负极片由集流体和涂覆在集流体表面的负极活性材料组成, 隔膜为聚酰亚胺纳 米纤维膜。 聚酰亚胺纳米纤维膜的厚度为 5 μ ιη。 聚酰亚胺纳米纤维膜的孔隙率 为 50%, 孔径为 0.1 μ ιη。 对比例一 The composite negative electrode sheet for a lithium ion battery is composed of a negative electrode sheet and a separator directly laminated on the surface of the negative electrode sheet, and the negative electrode sheet is composed of a current collector and a negative electrode active material coated on the surface of the current collector, and the separator is a polyimide nanofiber membrane. The polyimide nanofiber membrane has a thickness of 5 μm. The polyimide nanofiber membrane has a porosity of 50% and a pore diameter of 0.1 μm. Comparative example one
锂离子电池的制备方法  Method for preparing lithium ion battery
( 1 ) 负极片制备  (1) Preparation of negative electrode sheets
将 200克负极活性物质人造石墨、 3克粘结剂丁苯橡胶 (SBR)和 3克羧曱基 纤维素 (CMC)的混合物加入到 200克水中,然后在真空搅拌机中搅拌形成均匀的 浆料。 将该浆料均匀地涂布在 9微米的铜箔的两面, 控制涂布的面密度为 17.8 毫克 /平方厘米, 然后在 100°C下烘干, 辊压制得厚度为 120微米的负极片。  200 g of a mixture of negative active material artificial graphite, 3 g of binder styrene butadiene rubber (SBR) and 3 g of carboxymethylcellulose (CMC) was added to 200 g of water, and then stirred in a vacuum mixer to form a uniform slurry. . The slurry was uniformly coated on both sides of a 9 μm copper foil, and the coated surface density was controlled to be 17.8 mg/cm 2 , and then dried at 100 ° C, and pressed to obtain a negative electrode sheet having a thickness of 120 μm.
( 2 )正极片制备  (2) Preparation of positive electrode sheets
将 200克正极活性物质 LiCo02、 4克粘结剂聚偏二氟乙烯 (PVDF)、 6克导 电剂乙炔黑的混合物加入到 40克 N-曱基 - 2吡咯烷酮 (NMP)中, 然后在真空搅 拌机中搅拌形成均勾的正极浆料。 将该浆料均勾的涂布在 16微米的铝箔上, 控 制涂布的面密度为 34毫克 /平方厘米, 然后 120°C下烘干、 辊压、 裁切为 392毫 米 X78毫米的正极片, 其中含有 11.5克活性成份 LiCo02Adding a mixture of 200 g of the positive active material LiCo0 2 , 4 g of the binder polyvinylidene fluoride (PVDF), and 6 g of the conductive agent acetylene black to 40 g of N-fluorenyl-2-pyrrolidone (NMP), followed by vacuum The mixture was stirred in a mixer to form a positive electrode slurry. The slurry was uniformly coated on a 16 micron aluminum foil to control the coated areal density of 34 mg/cm 2 , and then dried, rolled, and cut into a positive film of 392 mm X 78 mm at 120 ° C. It contains 11.5 g of active ingredient LiCo0 2 .
隔膜采用商业化的聚烯烃隔膜 Celgard2400 (单层聚丙烯薄膜) , 然后将隔 膜与正负极极片卷绕, 经组装封装后注液、 密封, 最后活化并进行性能检验, 制得锂离子电池。  The separator is made of commercial polyolefin separator Celgard 2400 (single-layer polypropylene film), and then the separator is wound with the positive and negative pole pieces. After assembly and encapsulation, the liquid is injected, sealed, and finally activated and tested for performance to obtain a lithium ion battery. .
对比例二  Comparative example two
锂离子电池的制备方法  Method for preparing lithium ion battery
( 1 )锂离子电池用复合负极片制备  (1) Preparation of composite negative electrode sheets for lithium ion batteries
第一步 负极片制备方法  First step, preparation method of negative electrode sheet
将 200克负极活性物质人造石墨、 3克粘结剂丁苯橡胶 (SBR)和 3克羧曱基 纤维素 (CMC)的混合物加入到 200克水中,然后在真空搅拌机中搅拌形成均匀的 浆料。 将该浆料均匀地涂布在 9微米的铜箔的两面, 控制涂布的面密度为 17.8 毫克 /平方厘米, 然后在 100°C下烘干, 辊压制得厚度为 120微米的负极片。 第二步 水性聚合物胶体乳液的合成 200 g of a mixture of negative active material artificial graphite, 3 g of binder styrene butadiene rubber (SBR) and 3 g of carboxymethylcellulose (CMC) was added to 200 g of water, and then stirred in a vacuum mixer to form a uniform slurry. . The slurry was uniformly coated on both sides of a 9 micron copper foil to control the coated areal density to be 17.8. Milligrams per square centimeter, then dried at 100 ° C, and pressed to obtain a negative electrode sheet having a thickness of 120 μm. The second step of the synthesis of aqueous polymer colloidal emulsion
聚乙烯基吡咯烷酮 (PVP ) 水溶液中加入亲油性单体苯乙烯(St ) /丙烯酸 丁酯 (Ba ) /丙烯腈单体(AN )在水相中进行三元共聚, 其共聚组成为 PVP: St: Ba: AN=10:2:4:2(重量比)。  Polyvinylpyrrolidone (PVP) was added to the aqueous solution of styrene (St) / butyl acrylate (Ba ) / acrylonitrile monomer (AN ) in the aqueous phase for ternary copolymerization, the copolymerization composition of PVP: St : Ba: AN=10:2:4:2 (weight ratio).
该水性聚合物胶体乳液采用分步聚合: 在冷凝水的四口反应容器中, 加入 1000份蒸馏水和 100份聚乙婦基吡咯烷酮, 反应釜升温到 90°C , 搅拌溶解至物 料呈透明状时, 加入 20份亲油性单体苯乙烯和 2份过硫酸铵引发剂, 反应 20 小时, 变白色乳液, 加入 40份丙烯酸丁酯继续反应 2小时, 再加入 20份丙烯 腈单体, 并补加 1.5份过硫酸铵引发剂继续聚合 12小时, 即得到水性聚合物胶 体乳液。  The aqueous polymer colloidal emulsion is subjected to stepwise polymerization: 1000 parts of distilled water and 100 parts of polyethylidene pyrrolidone are added to a four-reaction reaction vessel of condensed water, and the reaction vessel is heated to 90 ° C, and stirred to dissolve until the material is transparent. Add 20 parts of lipophilic monomer styrene and 2 parts of ammonium persulfate initiator, react for 20 hours, turn white emulsion, add 40 parts of butyl acrylate to continue the reaction for 2 hours, then add 20 parts of acrylonitrile monomer, and add 1.5 parts of ammonium persulfate initiator was further polymerized for 12 hours to obtain an aqueous polymer colloidal emulsion.
第三步 浆料制备  The third step slurry preparation
制得的水性聚合物胶体乳液加入 15份白碳黑和 100份磷酸三乙酯增塑剂, 球磨 5小时, 制得水性聚合物浆料。  The obtained aqueous polymer colloidal emulsion was added to 15 parts of white carbon black and 100 parts of triethyl phosphate plasticizer, and ball-milled for 5 hours to prepare an aqueous polymer slurry.
第四步 涂覆  The fourth step
采用涂布设备将水性聚合物浆料涂覆在已制备好的铜箔负极片上, 再通过 100°C的热风和红外辐照的烘道挥发水分和增塑剂 , 即得到具有聚合物涂层的锂 离子电池用复合负极片。  The aqueous polymer slurry is coated on the prepared copper foil negative electrode sheet by a coating device, and the water and the plasticizer are volatilized by a hot air of 100 ° C and an infrared irradiation drying tunnel to obtain a polymer coating. Composite negative electrode sheets for lithium ion batteries.
( 2 )正极片制备  (2) Preparation of positive electrode sheets
将 200克正极活性物质 LiCo02、 4克粘结剂聚偏二氟乙烯 (PVDF)、 6克导 电剂乙炔黑的混合物加入到 40克 N-曱基 - 2吡咯烷酮 (NMP)中, 然后在真空搅 拌机中搅拌形成均勾的正极浆料。 将该浆料均勾的涂布在 16微米的铝箔上, 控 制涂布的面密度为 34毫克 /平方厘米, 然后 120°C下烘干、 辊压、 裁切为 392毫 米 X78毫米的正极片, 其中含有 11.5克活性成份 LiCo02Adding a mixture of 200 g of the positive active material LiCo0 2 , 4 g of the binder polyvinylidene fluoride (PVDF), and 6 g of the conductive agent acetylene black to 40 g of N-fluorenyl-2-pyrrolidone (NMP), followed by vacuum The mixture was stirred in a mixer to form a positive electrode slurry. The slurry was uniformly coated on a 16 micron aluminum foil to control the coated areal density of 34 mg/cm 2 , and then dried, rolled, and cut to 392 m at 120 ° C. M X78 mm positive electrode containing 11.5 g of active ingredient LiCo0 2 .
将此锂离子电池用复合负极片和正极片, 经组装封装后注液、 密封, 最后 活化并进行性能检验, 制得锂离子电池。  The composite negative electrode sheet and the positive electrode sheet for the lithium ion battery are assembled, packaged, injected, sealed, and finally activated and subjected to performance test to obtain a lithium ion battery.
以上实施例和对比例中制得的锂离子电池为实验电池, 用于下述效果实施 例性能测试。  The lithium ion batteries produced in the above examples and comparative examples were experimental batteries for the performance test of the following effect examples.
效果实施例  Effect embodiment
为对本发明实施例技术方案带来的有益效果进行有力支持, 特提供以下性 能测试:  In order to strongly support the beneficial effects brought by the technical solutions of the embodiments of the present invention, the following performance tests are provided:
1. 过充电测试  Overcharge test
测试方法如下: 将锂离子电池用 1C(1.6A)电流充电到 100 %充电态, 再用 3C(4.8A)电流充电到 10V恒压 2小时, 观察锂离子电池是否起火或***。  The test method is as follows: The lithium ion battery is charged to a 100% state of charge with a current of 1 C (1.6 A), and then charged to a constant voltage of 10 V for 2 hours with a current of 3 C (4.8 A) to observe whether the lithium ion battery is ignited or exploded.
2. 180 °C热冲击  2. 180 °C thermal shock
测试方法如下: 将锂离子电池用 1C(1.6A)电流充电到 100 %充电态,放置在 烘箱中, 烘箱温度以 5°C从室温升高到 150°C并保持 10分钟, 未出现短路情况 时继续以 5 °C升高至 180°C并保持 10分钟, 观察锂离子电池是否出现短路。 其 中锂离子电池电压跌落大于 0.2伏视为短路。  The test method is as follows: The lithium ion battery is charged to a 100% state of charge with a current of 1 C (1.6 A), placed in an oven, and the oven temperature is raised from room temperature to 150 ° C at 5 ° C for 10 minutes without short circuit. In the case, continue to increase to 5 ° C to 180 ° C for 10 minutes, observe whether the lithium-ion battery is short-circuited. The lithium ion battery voltage drop greater than 0.2 volts is considered a short circuit.
3. 短路安全试验  3. Short circuit safety test
测试方法如下: 将锂离子电池用 1C(1.6A)电流充电到 100 %充电态, 以 5 毫米 /秒的速度使直径 2.7 毫米的铁制圓形钉子穿透锂离子电池主体, 并监控锂 离子电池表面的温度及是否起火和***。  The test method is as follows: Lithium-ion battery is charged to 100% charge state with 1C (1.6A) current, and a 2.7 mm diameter iron round nail penetrates the lithium ion battery body at a speed of 5 mm/sec, and the lithium ion is monitored. The temperature of the battery surface and whether it is a fire or explosion.
4. 充放电循环测试  4. Charge and discharge cycle test
测试方法如下: 1C(1.6A)电流充电到 4.2伏, 再恒压至电流小于 80毫安, 1C(1.6A)电流放电到 3.0伏, 如此重复充放电, 并且获得第 500次放电容量与初 始放电容量的比值。 The test method is as follows: 1C (1.6A) current is charged to 4.2 volts, then constant voltage to current less than 80 mA, 1C (1.6A) current is discharged to 3.0 volts, thus repeating charge and discharge, and obtaining the 500th discharge capacity and initial The ratio of the initial discharge capacity.
以上实施例和对比例中制得的锂离子电池的性能测试结果如表 1所示。  The performance test results of the lithium ion batteries prepared in the above examples and comparative examples are shown in Table 1.
表 1. 实施例和对比例中制得的锂离子电池的性能测试结果  Table 1. Performance test results of lithium ion batteries prepared in the examples and comparative examples
Figure imgf000019_0001
Figure imgf000019_0001
由表 1 测试结果可看出: 本发明实施例锂离子电池用复合负极片制得的锂 离子电池较对比例制得的锂离子电池具有更高的耐热性、 更好的安全性能和更 好的循环性能。 其结果分析如下: 本发明实施例锂离子电池用复合负极片复合 有聚酰亚胺纳米纤维膜, 可以承受高温热冲击, 同时在内部局部短路条件下不 发生热失控, 锂离子电池用复合负极片在卷绕组装过程中不产生拉伸应力, 循 环过程中不会导致电芯变形引起内阻增大, 所以循环性能更好。  It can be seen from the test results of Table 1 that the lithium ion battery prepared by using the composite negative electrode sheet for lithium ion battery of the embodiment of the invention has higher heat resistance, better safety performance and more safety than the lithium ion battery prepared by the comparative example. Good cycle performance. The results are analyzed as follows: In the embodiment of the present invention, the composite negative electrode sheet for a lithium ion battery is compounded with a polyimide nanofiber membrane, which can withstand high temperature thermal shock, and does not cause thermal runaway under internal partial short circuit conditions, and a composite negative electrode for a lithium ion battery. The sheet does not generate tensile stress during the winding assembly process, and the internal resistance is not increased due to the deformation of the battery core during the cycle, so the cycle performance is better.

Claims

权 利 要 求 Rights request
1、 一种锂离子电池用复合负极片, 其特征在于, 所述锂离子电池用复合负 极片由负极片和复合在所述负极片表面的隔膜组成, 所述负极片由集流体和涂 覆在集流体表面的负极活性材料组成, 所述隔膜为聚酰亚胺纳米纤维膜。 1. A composite negative electrode sheet for lithium ion batteries, characterized in that, the composite negative electrode sheet for lithium ion batteries is composed of a negative electrode sheet and a separator compounded on the surface of the negative electrode sheet, and the negative electrode sheet is composed of a current collector and a coating The negative electrode active material is formed on the surface of the current collector, and the separator is a polyimide nanofiber membrane.
2、 如权利要求 1所述的一种锂离子电池用复合负极片, 其特征在于, 所述 聚酰亚胺纳米纤维膜的厚度为 5 μ m〜30 μ m。 2. A composite negative electrode sheet for lithium-ion batteries according to claim 1, characterized in that the thickness of the polyimide nanofiber membrane is 5 μm~30 μm.
3、 如权利要求 1或 2所述的一种锂离子电池用复合负极片, 其特征在于, 所述聚酰亚胺纳米纤维膜的孔隙率为 5%〜80%, 孔径为 0.01 μ ιη〜10 μ ηι。 3. A composite negative electrode sheet for lithium ion batteries according to claim 1 or 2, characterized in that the porosity of the polyimide nanofiber membrane is 5%~80%, and the pore diameter is 0.01 μm~ 10μm.
4、 一种锂离子电池用复合负极片的制备方法, 其特征在于, 包括以下步骤: 通过静电纺丝的方式将聚酰胺酸溶液喷涂在负极片表面, 所述负极片由集流体 和涂覆在集流体表面的负极活性材料组成, 然后进行机械辊压, 最后热亚胺化 处理将喷涂在负极片表面的聚酰胺酸转化为聚酰亚胺, 在负极片表面形成聚酰 亚胺纳米纤维膜, 得到锂离子电池用复合负极片。 4. A method for preparing a composite negative electrode sheet for lithium-ion batteries, which is characterized by including the following steps: spraying a polyamic acid solution on the surface of the negative electrode sheet by electrospinning, and the negative electrode sheet is composed of a current collector and a coating The negative active material is formed on the surface of the current collector, and then mechanically rolled. Finally, thermal imidization treatment converts the polyamic acid sprayed on the surface of the negative electrode into polyimide, forming polyimide nanofibers on the surface of the negative electrode. film to obtain a composite negative electrode sheet for lithium ion batteries.
5、 如权利要求 4所述的一种锂离子电池用复合负极片的制备方法, 其特征 在于, 所述聚酰胺酸溶液按如下制备: 取二元有机酸酐与有机二胺加入至有机 溶剂中, 搅拌, 发生缩合反应制得聚酰胺酸。 5. The method for preparing a composite negative electrode sheet for lithium ion batteries according to claim 4, characterized in that the polyamic acid solution is prepared as follows: taking binary organic acid anhydride and organic diamine and adding them to the organic solvent , stir, and condensation reaction occurs to prepare polyamic acid.
6、 如权利要求 5所述的一种锂离子电池用复合负极片的制备方法, 其特征 在于, 所述二元有机酸酐为均苯四曱酸二酐、 联苯四酸二酐、 异丙基二苯酐、 氧联苯四曱酸二酐、 二苯酮四酸二酐和双酚 Α二醚二酐中的一种或几种; 所述 有机二胺为 4,4-二氨基二苯醚、 3,4-二氨基二苯醚、 间苯二胺、 对苯二胺、 3,3- 二苯砜二胺、 联苯二胺和异丙基二苯胺中的一种或几种; 所述有机溶剂为 Ν,Ν- 二曱基曱酰胺、 Ν,Ν-二曱基乙酰胺、 Ν-2-曱基吡咯烷酮、 四氢呋喃和曱醇中的一 种或几种。 6. The method for preparing a composite negative electrode sheet for lithium ion batteries according to claim 5, wherein the binary organic acid anhydride is pyromellitic dianhydride, diphenyltetraic acid dianhydride, isopropyl dianhydride One or more of benzoyl diphenyl anhydride, oxybiphenyl tetracarboxylic acid dianhydride, benzophenone tetracarboxylic acid dianhydride and bisphenol A diether dianhydride; the organic diamine is 4,4-diaminodiphenyl One or more of ether, 3,4-diaminodiphenyl ether, m-phenylenediamine, p-phenylenediamine, 3,3-diphenylsulfonediamine, diphenyldiamine and isopropyldiphenylamine; The organic solvent is one of N, N-dimethylformamide, N, N-dimethylacetamide, N-2-methylpyrrolidone, tetrahydrofuran and methanol. species or several species.
7、 如权利要求 5或 6所述的一种锂离子电池用复合负极片的制备方法, 其 特征在于, 所述二元有机酸酐与有机二胺按摩尔比为 0.7〜1.1 : 1 , 有机溶剂的加 入量为二元有机酸酐和有机二胺总质量的 5〜8倍。 7. The method for preparing a composite negative electrode sheet for lithium ion batteries according to claim 5 or 6, wherein the molar ratio of the binary organic acid anhydride to the organic diamine is 0.7~1.1:1, and the organic solvent The addition amount is 5 to 8 times the total mass of binary organic acid anhydride and organic diamine.
8、 如权利要求 5或 6所述的一种锂离子电池用复合负极片的制备方法, 其 特征在于, 所述搅拌过程的温度为 0°C〜30°C , 搅拌时间为 2〜10小时。 8. The method for preparing a composite negative electrode sheet for lithium ion batteries according to claim 5 or 6, characterized in that the temperature of the stirring process is 0°C~30°C, and the stirring time is 2~10 hours .
9、 如权利要求 4所述的一种锂离子电池用复合负极片的制备方法, 其特征 在于, 所述静电纺丝的纺丝针头直径为 0.2 mm ~ 1.5mm, 电压为 100v ~ 20kv, 针头与接受电极的距离为 10cm ~ 35cm, 纺丝流量为 0.2〜1毫升 /小时。 9. The method for preparing a composite negative electrode sheet for lithium ion batteries according to claim 4, characterized in that the diameter of the spinning needle of the electrospinning is 0.2 mm ~ 1.5mm, the voltage is 100v ~ 20kv, and the needle The distance from the receiving electrode is 10cm ~ 35cm, and the spinning flow rate is 0.2 ~ 1 ml/hour.
10、如权利要求 4所述的一种锂离子电池用复合负极片的制备方法,其特征 在于,所述机械辊压的强度为 1 ~ 15兆帕,速度为 0.5〜1米 /分钟,辊压时间为 1 ~ 5分钟。 10. A method for preparing a composite negative electrode sheet for lithium ion batteries according to claim 4, characterized in that the intensity of the mechanical rolling is 1 to 15 MPa, the speed is 0.5 to 1 m/min, and the roller The pressing time is 1 ~ 5 minutes.
11、如权利要求 4所述的一种锂离子电池用复合负极片的制备方法,其特征 在于,所述热亚胺化处理是在氮气、氩气或真空下梯度升温,梯度升温为: 100 ~ 200°C保持 0.5 ~ 2小时, 200 ~ 250°C保持 0.5 ~ 2小时, 250 ~ 300°C保持 0.5 ~ 1.5 小时。 11. The method for preparing a composite negative electrode sheet for lithium ion batteries according to claim 4, characterized in that the thermal imidization treatment is a gradient temperature rise under nitrogen, argon or vacuum, and the gradient temperature rise is: 100 ~200°C for 0.5~2 hours, 200~250°C for 0.5~2 hours, 250~300°C for 0.5~1.5 hours.
12、 一种锂离子电池, 其特征在于, 所述锂离子电池包括锂离子电池用复合 负极片、 正极片、 非水电解液和外壳, 所述锂离子电池用复合负极片由负极片 和复合在所述负极片表面的隔膜组成, 所述负极片由集流体和涂覆在集流体表 面的负极活性材料组成, 所述隔膜为聚酰亚胺纳米纤维膜。 12. A lithium ion battery, characterized in that, the lithium ion battery includes a composite negative electrode sheet for lithium ion batteries, a positive electrode sheet, a non-aqueous electrolyte and a casing, and the composite negative electrode sheet for lithium ion batteries consists of a negative electrode sheet and a composite The negative electrode sheet is composed of a separator on the surface of the negative electrode sheet. The negative electrode sheet is composed of a current collector and a negative electrode active material coated on the surface of the current collector. The separator is a polyimide nanofiber membrane.
13、 如权利要求 12所述的锂离子电池, 其特征在于, 所述聚酰亚胺纳米纤 维膜的厚度为 5 μ m〜30 μ m。 13. The lithium-ion battery according to claim 12, wherein the thickness of the polyimide nanofiber film is 5 μm~30 μm.
14、如权利要求 12或 13所述的一种锂离子电池用复合负极片,其特征在于, 所述聚酰亚胺纳米纤维膜的孔隙率为 5%〜80%, 孔径为 0.01 μιη〜10μηι。 14. A composite negative electrode sheet for lithium-ion batteries according to claim 12 or 13, characterized in that: The polyimide nanofiber membrane has a porosity of 5% to 80% and a pore diameter of 0.01 μm to 10 μm.
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