WO2015096272A1 - 一种锂电池及其制备方法 - Google Patents

一种锂电池及其制备方法 Download PDF

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Publication number
WO2015096272A1
WO2015096272A1 PCT/CN2014/071643 CN2014071643W WO2015096272A1 WO 2015096272 A1 WO2015096272 A1 WO 2015096272A1 CN 2014071643 W CN2014071643 W CN 2014071643W WO 2015096272 A1 WO2015096272 A1 WO 2015096272A1
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Prior art keywords
lithium
positive electrode
lithium battery
current collector
electrolyte
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PCT/CN2014/071643
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English (en)
French (fr)
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吕正中
刘范芬
袁中直
刘金成
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惠州亿纬锂能股份有限公司
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Priority to US14/384,178 priority Critical patent/US9742031B2/en
Publication of WO2015096272A1 publication Critical patent/WO2015096272A1/zh

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    • 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
    • H01M10/056Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566Liquid materials
    • H01M10/0567Liquid materials characterised by the additives
    • 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
    • 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
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/05Accumulators with non-aqueous electrolyte
    • H01M10/056Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566Liquid materials
    • H01M10/0568Liquid materials characterised by the solutes
    • 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
    • H01M10/058Construction or 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
    • H01M4/131Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • 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
    • H01M4/36Selection of substances as active materials, active masses, active liquids
    • H01M4/48Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • 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
    • H01M4/36Selection of substances as active materials, active masses, active liquids
    • H01M4/48Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • 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
    • H01M4/70Carriers or collectors characterised by shape or form
    • H01M4/72Grids
    • H01M4/74Meshes or woven material; Expanded metal
    • 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
    • H01M4/70Carriers or collectors characterised by shape or form
    • H01M4/72Grids
    • H01M4/74Meshes or woven material; Expanded metal
    • H01M4/745Expanded metal
    • 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
    • H01M50/449Separators, membranes or diaphragms characterised by the material having a layered structure
    • 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
    • H01M50/449Separators, membranes or diaphragms characterised by the material having a layered structure
    • H01M50/457Separators, membranes or diaphragms characterised by the material having a layered structure comprising three or more layers
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00Batteries for particular applications
    • H01M2220/30Batteries in portable systems, e.g. mobile phone, laptop
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00Electrolytes
    • H01M2300/0017Non-aqueous electrolytes
    • H01M2300/0025Organic electrolyte
    • H01M2300/0028Organic electrolyte characterised by the solvent
    • 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
    • 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
    • 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
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present invention relates to the field of lithium battery technology, and more particularly to a lithium battery having high power, high energy, low self-discharge rate and a preparation method thereof.
  • a lithium battery having high power, high energy, low self-discharge rate and a preparation method thereof.
  • High-energy and lithium batteries have become the focus of the battery industry.
  • Lithium batteries are classified into lithium primary batteries (primary batteries) and lithium ion batteries (secondary batteries).
  • the lithium primary battery has a higher energy density, mainly because the lithium metal negative electrode has a larger theoretical capacity than the lithium ion battery, and the theoretical lithium capacity of the lithium metal negative electrode is 3860 mAh/g.
  • the theoretical gram capacity of the carbonaceous negative electrode was 372 mAh/g.
  • side reactions may occur, resulting in irreversible capacity generation.
  • the carbon-based negative electrode reacts with the electrolyte at the solid-liquid phase interface to form a solid electrolyte interface film (ie, SEI film), and this process loses the capacity of the positive electrode portion.
  • the capacity utilization rate of conventional lithium ion battery materials is about 90%.
  • the self-discharge rate of the lithium ion battery is high, the self-discharge rate of the lithium primary battery is low, and the output power of the lithium primary battery is low.
  • the second is to make the electrode very thin, the metal lithium is weak due to its own tensile strength, thin lithium
  • the sheet is easily broken during the preparation of the battery; while the lithium ion battery is coated on the current collector (such as copper foil) by using a carbonaceous material having strong electrical conductivity, the thickness of the pole piece can be controlled, thereby being able to satisfy Power requirements.
  • the high-power primary lithium battery increases the tensile strength of the lithium metal negative electrode by two methods: First, the mechanical strength is increased by increasing the thickness of the metallic lithium in the negative electrode. The second is to increase the mechanical tensile strength of the lithium metal by spraying or pressing it onto a thin conductive support such as a metal mesh or metal strip (copper foil, nickel mesh, etc.).
  • the utilization rate of the lithium metal negative electrode is significantly reduced, the energy density of the battery is reduced, and since the lithium metal negative electrode is excessively left in this design, the battery has a large safety hazard;
  • the spraying or pressing method needs to be carried out in a dry or inert working atmosphere of lithium metal such as nitrogen or argon, so the manufacturing environment is very demanded, and the manufacturing process is obviously complicated, and it is difficult to realize continuous production, and the negative electrode The uniformity of the sheet is difficult to guarantee.
  • One of the research directions of high-energy lithium-ion batteries is to develop high-capacity lithium-ion battery anode materials, including nitrides, silicon-based materials, and tin-based materials.
  • the negative electrode material will increase in volume due to the intercalation of lithium ions. After delithiation, the volume cannot be restored to the original state, causing the battery to expand in volume, causing the electrode to become powdery and lose electrochemical activity. This leads to a loss of capacity and a significant safety hazard.
  • a lithium battery having high power, high energy, low self-discharge rate is to provide a preparation of the lithium battery
  • the technical solution of the present invention is: a lithium battery comprising a positive electrode sheet, a negative current collecting substrate, a separator interposed between the positive electrode sheet and the negative current collecting substrate, and an electrolyte;
  • the positive electrode sheet includes a positive electrode current collector, a positive electrode film attached to the positive electrode current collector and containing a positive electrode active material, and a positive electrode tab welded to the positive electrode current collector;
  • the anode current collecting substrate comprises a negative electrode current collector and a negative electrode tab welded on the negative electrode current collector;
  • the negative electrode current collecting substrate is made of a metal foil or a metal mesh having a thickness of 6 to 25 ⁇ m a current collecting substrate having a flat or concave-convex structure with a thickness of 6 to 60 ⁇ m;
  • the electrolytic solution contains a lithium salt and a solvent, the lithium salt is lithium hexafluorophosphate, and the concentration of the lithium salt in the electrolytic solution is 1.5 to 7 mol/L.
  • the metal foil or metal mesh having the planar or concave-convex structure described above is formed by roll pressing or molding to form a negative electrode current collecting substrate having a concave-convex structure.
  • the current collector during the charging process, the lithium in the positive active material is desorbed and deposited on the surface of the negative current collecting substrate to form a metal lithium negative active material; at the same time, the lithium in the positive active material is desorbed by a charging method to form a positive active material. . Therefore, a thin metal lithium layer is plated on the surface of the negative current collecting substrate by electroplating during the charging process, which saves lithium battery space and improves the energy density and power density of the lithium battery.
  • the convex structure metal foil or metal mesh can provide a space for the current collector to expand and contract, and provide an electrolyte holding space to avoid the positive and negative current collectors from being broken due to the lithium plating volume expansion of the anode current collector, and at the same time improve the retention of the electrolyte in the battery. the amount.
  • the electrolyte of the lithium battery of the present invention is a high lithium salt concentration electrolyte system, has a high concentration of anions and cations, and a high lithium ion migration number is favorable for lithium ions.
  • the high lithium salt concentration electrolyte system has a higher viscosity, effectively avoiding the formation of metallic lithium dendrites due to uneven deposition of metallic lithium (high lithium ion concentration)
  • It is beneficial to the uniform growth of lithium metal of the negative electrode which is beneficial to reduce the space charge layer generated by the anion depletion on the surface of the metal lithium negative electrode, thereby reducing the electric field driving force of the non-uniform deposition of metallic lithium; the high viscosity system is increased to some extent.
  • the resistance of lithium dendrite growth makes the uniform and dense growth of metallic lithium deposited on the negative metal foil, and the stability and safety are greatly improved.
  • the cathode current collector is an aluminum foil having a thickness of 12 to 25 ⁇ m.
  • the positive electrode active material is a lithium intercalation compound capable of reversibly intercalating and deintercalating lithium ions.
  • the positive electrode active material is at least one of lithium cobaltate, lithium manganate, lithium nickel cobalt manganese oxide, lithium iron phosphate, and lithium-rich multicomponent.
  • the positive electrode active material of the present invention is preferably, but not limited to, at least one of lithium cobaltate, lithium manganate, lithium nickel cobalt manganese oxide, lithium iron phosphate, and lithium-rich multi-material, and those skilled in the art may select other reversibles as needed.
  • a lithium intercalation compound that intercalates and deducts lithium ions is used as a positive electrode active material.
  • the metal foil is an aluminum foil, a tin foil, a nickel foil or a copper foil
  • the metal mesh is an aluminum mesh, a tin mesh, a nickel mesh or a copper mesh.
  • the anode current collecting substrate of the present invention is preferably, but not limited to, formed of aluminum foil, tin foil, nickel foil, copper foil, aluminum mesh, tin mesh, nickel mesh or copper mesh, and those skilled in the art may select other metal foils according to actual conditions and needs.
  • the separator is a polypropylene/polyethylene/polypropylene three-layer separator, or a polypropylene single-layer separator, or a polyethylene single-layer separator, or the surface is coated with metal oxide. Polypropylene or polyethylene separator.
  • the solvent in the electrolytic solution includes ethylene carbonate, cesium carbonate, dinonyl carbonate, and an additive.
  • the mass ratio of the ethylene carbonate, cesium carbonate, and dinonyl carbonate is 1:1:1.
  • the additive is at least one of dinonyl decylphosphonate and diethyl ethate.
  • the electrolyte of the lithium battery of the present invention contains a solvent having a flame retarding effect, which can effectively improve the battery. Security performance.
  • the electrolyte solution is a bifunctional high lithium salt concentration electrolyte system to which a flame retardant solvent is added, and simultaneously solves two problems of rapid migration of lithium ions and stabilization of the lithium layer of the negative electrode.
  • the additive is contained in an amount of 5 to 25% by mass based on the total mass of the solvent.
  • the content of the additive is too small, and the flame retardant effect is not well.
  • the inventors of the present invention have obtained a lot of experimental research, and the content of the additive is preferably 5 to 25% of the total mass of the solvent. Improve the safety of the battery.
  • another object of the present invention is to provide a method for preparing a lithium battery as described above. To achieve the object, the technical solution of the present invention is as follows: A method for preparing a lithium battery as described above, comprising the following steps:
  • the positive electrode active material is made into a positive electrode slurry, and the positive electrode slurry is uniformly coated on the positive electrode current collector to obtain a positive electrode current collector to which a positive electrode film containing a positive electrode active material is attached, which will adhere
  • the positive electrode current collector having the positive electrode film is cold-pressed, cut, and the positive electrode tab is welded to obtain a positive electrode sheet;
  • the positive electrode sheet, the separator film and the anode current collecting substrate are made into a lithium battery cell, and then the battery core is placed in the packaging shell to inject the electrolyte solution and then sealed;
  • the lithium battery obtained in the step (5) is formed into an aging product, and a lithium battery is obtained.
  • the polar active material is uniformly stirred with a polyvinylidene fluoride binder and a conductive carbon in a solvent of N-fluorenylpyrrolidone to prepare a positive electrode slurry.
  • the lamination or winding process forms the positive electrode sheet, the separator, and the anode current collecting substrate into a lithium battery cell.
  • the positive electrode sheet, the separator film and the negative electrode current base are made into a lithium battery cell by a lamination or winding process, and the structure of the lithium battery cell and the lamination or winding process are both existing and existing The technology is the same.
  • the aging process of the battery is charged to a voltage of 0.05 to 0.2 C to 4.0 V, then charged to 4.2 V with a current of 0.2 to 1 C, and aged for 24 to 72 h in an environment of 40 to 50 ° C.
  • the first process of the lithium battery is charged to a voltage of 0.05 to 0.2 C to 4.0 V, and then charged to a voltage of 4.2 V with a current of 0.2 to 1 C, and a small charging current is caused to escape from the positive electrode material.
  • Li + is slowly deposited on the negative current collector copper foil to form a dense lithium layer, which improves the safety of the battery.
  • the lithium battery of the invention has the characteristics of high power, high energy and low self-discharge rate, and can meet the requirements of continuous upgrading of functions of electronic devices, and thus can be widely used in electronic devices.
  • the lithium battery of the present invention is preferably but not limited to As an electronic cigarette battery.
  • the use of the present invention is not limited thereto, and is merely illustrative here.
  • the negative electrode is a current collecting substrate having a planar or concave-convex structure, and is coated with a metal lithium layer on the surface thereof, specifically during charging.
  • Electroplating is used to deposit a thin layer of dense metal lithium on the anode current collector, and metal lithium is embedded in the cathode material in the form of Li + during discharge, while the concave-convex structure metal foil or metal mesh
  • the utility model can provide a space for the fluid to expand and contract, and provide an electrolyte holding space to prevent the anode current collector from being broken due to the volume expansion of the lithium plating, and the concave-convex structure can increase the amount of the electrolyte in the battery;
  • the electrolyte with different lithium ion battery is a high lithium salt concentration electrolyte system with high anion and cation concentration.
  • the high lithium ion migration number facilitates the rapid migration of lithium ions and solves the rapid migration of lithium metal.
  • the high lithium salt concentration electrolyte system has a high viscosity, effectively avoiding the occurrence of metallic lithium dendrites due to uneven deposition of metallic lithium (high lithium ion concentration is beneficial to the growth of the negative metal lithium). It is beneficial to reduce the space charge layer generated by the anion depletion on the surface of the metal lithium negative electrode, thereby reducing the electric field driving force of the non-uniform deposition of metallic lithium; the high viscosity system increases the resistance of lithium dendrite growth to some extent, so that deposition The metallic lithium on the negative metal foil is hooked, densely grown, and has great stability and safety. High.
  • the lithium battery of the present invention has the following advantages:
  • the lithium battery of the present invention utilizes electroplating. During the charging process of the lithium battery, the positive electrode material is desorbed from Li + and deposited on the negative current collector to form a thin layer of lithium, based on the metal foil as a set.
  • the way of fluid and lithium deposition not only increases the tensile strength of the pole piece but also improves the rapid migration ability of lithium ions, thereby increasing the power density;
  • the negative electrode is a metal foil or metal mesh with a convex structure, which can provide a space for the current collector to expand and contract, and avoid the negative electrode current collector due to the lithium plating volume.
  • the expansion causes the positive and negative current collectors to break, and the safety is greatly improved;
  • the present invention has a structure similar to that of a primary battery, and has an extremely low self-discharge rate.
  • the preparation method of the lithium battery of the invention is simple and convenient to operate, and can combine the high-energy of the primary lithium battery and the high power of the rechargeable lithium ion battery, greatly improving the energy density and power density of the lithium battery, and has extremely low Self-discharge rate.
  • the lithium battery of the invention has the characteristics of high power, high energy and low self-discharge rate, and can meet the requirements of continuously upgrading the functions of electronic devices, and can be widely used in electronic devices.
  • FIG. 1 is a schematic cross-sectional view showing an embodiment of a negative electrode current collecting substrate in a lithium battery according to the present invention.
  • 2 is a schematic cross-sectional view showing another embodiment of a negative electrode current collecting substrate in a lithium battery according to the present invention.
  • 3 is a comparison chart of discharge curves of a lithium battery of Example 1, Comparative Example 1 and Comparative Example 2 at 100 mA.
  • 4 is a comparison diagram of discharge curves of a lithium battery of Example 1, Comparative Example 1 and Comparative Example 2 at 1000 mA.
  • Figure 5 is a graph showing the volume ratio energy of a lithium battery of Example 1, Comparative Example 1 and Comparative Example 2 of the present invention.
  • Embodiment 1 An embodiment of a lithium battery of the present invention is prepared by the following method: (1) Preparation of a positive electrode sheet: Lithium cobaltate (LiCo0 2 with a gram capacity of 140 mAh/g) ) is a positive electrode active material, mixed with a binder PVDF and a conductive agent Super-P in a mass ratio of 95: 2: 3 in NMP to form a positive electrode slurry, and a positive electrode slurry at a density of 33.0 mg/cm 2 The material is coated on both sides of an aluminum foil having a thickness of 16 ⁇ m and a length of 168 mm.
  • Lithium cobaltate LiCo0 2 with a gram capacity of 140 mAh/g
  • the length of the positive electrode paste coated on the aluminum foil is 130 mm and 152 mm, respectively, and is cut into a width of 42 mm and a thickness of 0.107 by cold pressing. a pole piece of mm, and welding the positive electrode tab to obtain a positive electrode sheet with a positive electrode film attached to the surface;
  • (2) Preparation of negative electrode current collecting substrate A copper foil having a length of 153 mm and a width of 44 mm was cut into a copper foil of 9 ⁇ m, and a negative electrode current collector having a thickness of 20 ⁇ m and having a concave-convex structure was formed by rolling or molding. Figure 1, and welding the negative electrode tab on the current collector to obtain a negative current collecting matrix;
  • separator a polypropylene/polyethylene/polypropylene ( ⁇ / ⁇ / ⁇ ) three-layer separator with a thickness of 16 ⁇ m, a length of 320 mm and a width of 46 mm;
  • Lithium fluoride LiPF 6
  • EC ethylene carbonate
  • EMC ethyl lanthanum carbonate
  • DMC dinonyl carbonate
  • DMMP dimethyl sulfonate
  • the solvent is ethylene carbonate (EC), ethyl lanthanum carbonate (EMC), dinonyl carbonate (DMC)
  • EC ethylene carbonate
  • EMC ethyl lanthanum carbonate
  • DMC dinonyl carbonate
  • the mass of dimethyl sulfonate (DMMP) is 10% of the total mass of the solvent
  • concentration of lithium hexafluoroacetate (LiPF 6 ) in the obtained electrolyte is 5mol/L;
  • Step (5) Formation and aging of lithium battery: The lithium battery obtained in step (5) is charged to 4.0V with a current of 13mA (0.05C), and then charged to 4.2V with a current of 52mA (0.2C), and then The lithium battery was molded in an oven at 45 ° C for 48 hours to obtain a lithium battery of the model 1 of the present invention.
  • Embodiment 2 An embodiment of the lithium battery of the present invention is prepared by the following method: (1) Preparation of a positive electrode sheet: lithium nickel cobalt manganese oxide having a gram capacity of 146 mAh/g ( LiNi.. 4 Co.. 2 Mn..
  • the positive electrode active material is a positive electrode active material, mixed with a binder PVDF and a conductive agent Super-P in a mass ratio of 94.5: 2: 3.5 in NMP, and made into a positive electrode.
  • Slurry, the positive electrode slurry was double-coated on an aluminum foil having a thickness of 16 ⁇ m and a length of 168 mm at a density of 30.0 mg/cm 2 , and the length of the positive electrode paste coated on both sides of the aluminum foil was 130 mm and 152 mm, respectively.
  • the cold piece is cut into a pole piece having a width of 42 mm and a thickness of 0.107 mm, and the positive electrode tab is welded to obtain a positive electrode sheet having a positive electrode film attached to the surface;
  • Lithium fluoride LiPF 6
  • EC ethylene carbonate
  • EMC ethyl lanthanum carbonate
  • DMC diterpene carbonate
  • DEEP diethyl ethate
  • the solvent is ethylene carbonate (EC), ethyl lanthanum carbonate (EMC), dinonyl carbonate (DMC)
  • EC ethylene carbonate
  • EMC ethyl lanthanum carbonate
  • DMC dinonyl carbonate
  • the mass of ethyl ester S-diethyl ester (DEEP) accounts for 5% of the total mass of the solvent, and the obtained electrolyte has a history of lithium hexafluoride (LiPF 6 ).
  • the concentration is 7mol/L;
  • step (5) Formation and aging of lithium battery: The lithium battery obtained in step (5) is charged to 4.0V with a current of 50mA (0.2C), and then charged to 4.2V with a current of 250mA (1C), and then lithium is charged. The battery was aged in a 50 ° C oven for 36 h to obtain a lithium battery of the model 2 of the present invention.
  • Embodiment 3 An embodiment of a lithium battery of the present invention is prepared by the following method: (1) Preparation of a positive electrode sheet: Lithium manganate (LiMn0 2 with a gram capacity of 100 mAh/g) ) is a positive electrode active material, and the binder PVDF and the conductive agent Super-P are mixed and stirred uniformly in NMP at a mass ratio of 94.5: 2: 3.5 to prepare a positive electrode slurry, and the positive electrode slurry is prepared at a density of 27.0 mg/cm 2 . The material is coated on both sides of an aluminum foil having a thickness of 16 ⁇ m and a length of 168 mm.
  • Lithium manganate LiMn0 2 with a gram capacity of 100 mAh/g
  • the binder PVDF and the conductive agent Super-P are mixed and stirred uniformly in NMP at a mass ratio of 94.5: 2: 3.5 to prepare a positive electrode slurry, and the positive electrode slurry is prepared at
  • the length of the positive electrode paste coated on the aluminum foil is 130 mm and 152 mm, respectively, and is cut into a width of 42 mm and a thickness of 0.102 by cold pressing. a pole piece of mm, and welding the positive electrode tab to obtain a positive electrode sheet with a positive electrode film attached to the surface;
  • separator a polypropylene/polyethylene/polypropylene ( ⁇ / ⁇ / ⁇ ) three-layer separator with a thickness of 16 ⁇ m, a length of 320 mm and a width of 46 mm;
  • Lithium fluoride LiPF 6
  • EC ethylene carbonate
  • EMC ethyl lanthanum carbonate
  • DMC dinonyl carbonate
  • DMMP decyl decyl phosphate
  • DEEP diethyl diethyl phosphate
  • the solvent is ethylene carbonate (EC) or ethyl lanthanum carbonate (EMC)
  • EC ethylene carbonate
  • EMC ethyl lanthanum carbonate
  • DMC diterpene carbonate
  • the mass of ester (DMMP) and diethyl ethate (DEEP) and 20% of the total mass of the solvent, the concentration of lithium hexafluoride (LiPF 6 ) in the obtained electrolyte is 1.5 mol / L;
  • step (5) Formation and aging of lithium battery:
  • the lithium battery obtained in step (5) is charged to 4.0V with a current of 15mA (0.1C), and then charged to 4.2V with a current of 75mA (0.5C), and then
  • the lithium battery of the present invention was molded by aging the lithium battery in an oven at 40 ° C for 72 hours.
  • Embodiment 4 An embodiment of a lithium battery of the present invention is prepared by the following method: (1) Preparation of a positive electrode sheet: Lithium cobaltate (LiCo0 2 with a gram capacity of 140 mAh/g) And a mixture of lithium manganate (LiMn0 2 ) having a gram capacity of 100 mAh/g is a positive electrode active material, and is uniformly mixed with the binder PVDF and the conductive agent Super-P in a mass ratio of 95:2:3 in NMP.
  • a positive electrode slurry was prepared, and the positive electrode slurry was double-coated on an aluminum foil having a thickness of 12 ⁇ m and a length of 168 mm at a density of 28 mg/cm 2 , and the length of the positive electrode paste coated on the aluminum foil was 130 mm. And 152mm, cold-pressed into a pole piece having a width of 42mm and a thickness of 0.102mm, and welding the positive electrode tab to obtain a positive electrode sheet with a positive electrode film attached to the surface;
  • separator a polypropylene single-layer separator with a thickness of 12 ⁇ m, a length of 320 mm and a width of 46 mm;
  • Lithium fluoride LiPF 6 is added to a solvent, and uniformly mixed to obtain an electrolyte, wherein the solvent is ethylene carbonate (EC) or ethyl lanthanum carbonate (EMC).
  • the solvent is ethylene carbonate (EC) or ethyl lanthanum carbonate (EMC).
  • DMC dinonyl carbonate
  • DMMP dimethyl decyl phosphate
  • DEEP diethyl diethyl phosphate
  • the solvent is ethylene carbonate (EC) or ethyl lanthanum carbonate (EMC).
  • DMC diterpene carbonate
  • step (5) Formation and aging of lithium battery:
  • the lithium battery obtained in step (5) is charged to 4.0V with a current of 13mA (0.05C), and then charged to 4.2V with a current of 52mA (0.2C), and then
  • the lithium battery of the fourth embodiment of the present invention was obtained by aging the lithium battery in an oven at 48 ° C for 24 hours.
  • Embodiment 5 An embodiment of the lithium battery of the present invention is prepared by the following method: (1) Preparation of a positive electrode sheet: lithium nickel cobalt manganese oxide having a gram capacity of 146 mAh/g ( LiNio.4Coo.2Mno.4O2) is a positive electrode active material, mixed with a binder PVDF and a conductive agent Super-P in a mass ratio of 95: 2: 3 in NMP, and made into a positive electrode slurry, at 32 mg/cm. Density of 2 The positive electrode slurry was coated on both sides of an aluminum foil having a thickness of 25 ⁇ m and a length of 168 mm.
  • the length of the positive electrode paste coated on the aluminum foil was 130 mm and 152 mm, respectively, and was cut into width by cold pressing. a 42 mm, 0.107 mm thick pole piece, and a positive electrode tab is welded to obtain a positive electrode sheet with a positive electrode film attached to the surface;
  • an aluminum mesh of 6 ⁇ m is cut into an aluminum mesh having a length of 153 mm and a width of 44 mm.
  • the negative current collector formed in this embodiment is an aluminum mesh having a planar structure with a thickness of 6 ⁇ m. Welding the negative electrode tab on the current collector to obtain a negative current collecting matrix;
  • Lithium fluoride LiPF 6
  • EC ethylene carbonate
  • EMC ethyl lanthanum carbonate
  • DMC dinonyl carbonate
  • DMMP dimethyl sulfonate
  • the solvent is ethylene carbonate (EC), ethyl lanthanum carbonate (EMC), dinonyl carbonate (DMC)
  • EMC ethyl lanthanum carbonate
  • DMC dinonyl carbonate
  • the quality of dimethyl decyl phthalate (DMMP) and 15% of the total mass of the solvent the concentration of lithium hexafluorophosphate (LiPF 6 ) in the obtained electrolyte is 6 mol / L ;
  • the step (5) will be obtained with a current of 50 mA (0.2 C).
  • the lithium battery was charged to 4.0 V, and then charged to 4.2 V with a current of 250 mA (1 C), and then the lithium battery was aged in a 42 ° C oven for 60 hours to form a lithium battery of Example 5 of the present invention.
  • Comparative Example 1 A comparative example of the lithium battery of the present invention was prepared by the following method: (1) Preparation of a positive electrode sheet: Lithium cobaltate having a gram capacity of 140 mAh/g (LiCo0 2 ) is a positive electrode active material, mixed with a binder PVDF and a conductive agent Super-P in a mass ratio of 95: 2: 3 in NMP to form a positive electrode slurry, and a positive electrode slurry at a density of 28.0 mg/cm 2 The material is coated on both sides of an aluminum foil having a thickness of 16 ⁇ m and a length of 120 mm.
  • Lithium cobaltate having a gram capacity of 140 mAh/g Lithium cobaltate having a gram capacity of 140 mAh/g (LiCo0 2 ) is a positive electrode active material, mixed with a binder PVDF and a conductive agent Super-P in a mass ratio of 95: 2: 3 in NMP to form a positive electrode slurry, and
  • the length of the positive electrode paste coated on both sides of the aluminum foil is 82 mm and 100 mm, respectively, and is cut into a width of 42 mm and a thickness of 0.093 by cold pressing. Mm pole piece, and welding the positive electrode tab to obtain a positive electrode sheet with a positive electrode film attached to the surface;
  • the film is coated on a copper foil having a thickness of 9 ⁇ m and a length of 105 mm, and is cut into a pole piece having a width of 44 mm and a thickness of 0.09 mm by cold pressing, and the negative electrode tab is welded to obtain a negative electrode sheet having a negative electrode film attached to the surface;
  • separator a polypropylene/polyethylene/polypropylene (PP/PE/PP) three-layer separator with a thickness of 16 ⁇ m, length 265 mm, width 46 mm;
  • PP/PE/PP polypropylene/polyethylene/polypropylene
  • Lithium fluoride LiPF 6
  • EC ethylene carbonate
  • EMC ethyl lanthanum carbonate
  • DMC dinonyl carbonate
  • LiPF 6 has a concentration of 1 mol/L
  • Comparative Example 2 A comparative example of the lithium battery of the present invention, the lithium battery of the present comparative example was prepared by the following method: (1) Preparation of a positive electrode sheet: manganese dioxide (Mn0 2 with a gram capacity of 270 mAh/g) ) is a positive electrode active material, and the binder PVDF and the conductive agent Super-P and KS-6 are mixed and stirred in a mass ratio of 90:3:3.5:3.5 in NMP to prepare a positive electrode slurry, according to 28.0 mg/ Density of cm 2 The positive electrode slurry was coated on both sides of an aluminum foil having a thickness of 16 ⁇ m and a length of 120 mm.
  • Mn0 2 with a gram capacity of 270 mAh/g is a positive electrode active material
  • the binder PVDF and the conductive agent Super-P and KS-6 are mixed and stirred in a mass ratio of 90:3:3.5:3.5 in NMP to prepare a positive electrode slurry, according to 28.0 mg/ Den
  • the length of the positive electrode paste coated on both sides of the aluminum foil was 82 mm and 100 mm, respectively, and was cut into cold pressed pieces. a pole piece having a width of 44 mm and a thickness of 0.108 mm, and welding the positive electrode tab to obtain a positive electrode sheet having a positive electrode film attached to the surface;
  • separator a polypropylene/polyethylene/polypropylene (PP/PE/PP) three-layer separator with a thickness of 16 ⁇ m, a length of 230 mm and a width of 46 mm;
  • PP/PE/PP polypropylene/polyethylene/polypropylene
  • Example 6 Formation and aging of lithium battery: The lithium battery obtained in step (5) is discharged for 12 minutes (1% of capacity) with a current of 13 mA (0.05 C), and then the lithium battery is aged in a 45 ° C oven for 48 hours. After molding, a lithium battery of Comparative Model 2 model number 68500 was obtained.
  • Example 6 The lithium batteries prepared in the above Examples 1-5 were respectively discharged at 100 mA and 1000 mA, and their discharge capacities and platform voltages are shown in Table 1: Table 1 Discharge cut-off power 1000mA put 1000mA put 100mA discharge 100mA discharge group
  • Example 1 The discharge curves of the lithium batteries produced in Example 1, Comparative Example 1 and Comparative Example 2 at 100 mA and 1000 mA are shown in FIG. 3 and FIG. 4, respectively, and the battery models are selected according to Example 1 and Comparative Examples 1 and 2.
  • the lithium battery produced by the present invention simultaneously has a primary lithium
  • Li + which is discharged from the positive electrode during the charging process deposits a thin metal lithium layer on the surface of the negative current collector to increase the power density of the battery, and the negative electrode does not need to be coated.
  • the sheet saves battery space and increases the volumetric energy density of the battery; in addition, the electrolyte of the invention is a bifunctional high lithium salt concentration electrolyte system containing a flame retardant solvent, and simultaneously solves the rapid migration of lithium ions and stabilizes the lithium layer of the negative electrode.
  • the lithium battery prepared by the method of the invention combines the high energy of the primary lithium battery and the high power of the lithium ion battery, greatly improves the energy density and power density of the battery, and has a very low self-discharge rate. It can be used as a primary battery or a lithium ion battery with low cycle requirements.

Abstract

 本发明公开一种锂电池,所述锂电池包括正极片、负极集流基体、介于正极片和负极集流基体之间的隔离膜、电解液;所述正极片包括正极集流体、附着在所述正极集流体上含有正极活性材料的正极膜片、焊接在所述正极集流体上的正极极耳;所述负极集流基体包括负极集流体、焊接在所述负极集流体上的负极极耳;所述负极集流基体为由厚度为6~25μm的金属箔材或金属网制成的、厚度为6~60μm具有平面或凹凸结构的集流基体;所述电解液包含锂盐和溶剂,所述锂盐为六氟磷酸锂,且所述电解液中锂盐的浓度为1.5〜7mol/L。本发明的锂电池具有高功率、高能量和低自放电率的特性。同时,本发明还公开了所述锂电池的制备方法及用途。

Description

说 明 书 一种锂电池及其制备方法 技术领域 本发明属于锂电池技术领域, 尤其是一种具备高功率、 高能量、 低自放电 率的锂电池及其制备方法。 背景技术 近年来, 随着科技不断发展,电子设备的功能不断升级,因此对锂电池的能量 及倍率性能提出了更高的要求, 高能及锂电池已成为电池行业的重点研究方向。 锂电池分为锂原电池 (一次电池)和锂离子电池 (二次电池)。 相对而言, 锂原 电池具有更高的能量密度, 主要因其釆用锂金属负极比锂离子电池釆用碳基负 极的理论克容量大, 锂金属负极的理论克容量为 3860mAh/g, 而碳质负极的理 论克容量为 372mAh/g。 另外, 锂离子电池正、 负极材料在充放电过程中, 会发 生副反应, 从而导致不可逆容量产生。 且锂离子电池在首次充电过程碳基负极 与电解液在固液相界面发生反应, 形成固体电解质界面膜(即 SEI膜), 这个过 程会损失正极部分容量。 基于以上两点, 常规锂离子电池材料的容量利用率约 为 90%。 另外, 锂离子电池自放电率较高, 锂原电池的自放电率较低, 而锂原 电池的缺点输出功率较低。 主要是因为对于锂原电池, 通常有两种方法来得到。 一是提高电极本身的导电性来提高功率密度, 但对于金属锂一次电池而言, 无 法通过这种办法实现; 二是将电极做得很薄, 金属锂由于本身抗拉强度差, 薄 的锂片在电池制备过程很容易断裂; 而锂离子电池由于其负极是使用本身具有 强导电性的碳质材料涂覆在集流体(如铜箔)上, 因此极片的厚度可以控制, 从而能够满足功率要求。 基于以上描述, 目前关于锂电池的研究主要集中于提高一次电池的功率密 度和提高可充电锂离子电池的能量密度。 高功率一次锂电池通过两种方法来增 加锂金属负极的抗拉强度: 其一是通过增加负极中金属锂的厚度来提高机械强 度; 其二是通过将锂金属用喷涂或压制的方式加入到薄的导电支撑件如金属网 或金属带上(铜箔、 镍网等) 以提高其机械抗拉强度。 对于上述方法一, 明显降低了锂金属负极的利用率, 减少了电池的能量密 度, 且由于在这种设计中锂金属负极过多剩余, 对电池带来^ ί艮大的安全隐患; 而对于上述方法二, 利用喷涂或压制的方式需要在干燥或者相对锂金属惰性的 工作气氛如氮气或氩气中进行, 因此对制作环境要求很高, 且使制造工艺明显 复杂, 难以实现连续生产, 负极片的均匀性难以保证。 高能锂离子电池的研究方向之一是开发高容量锂离子电池负极材料, 包括 氮化物、 硅基材料、 锡基材料等。 而这类负极材料在充放电过程由于锂离子的 嵌入会导致体积增大, 而脱锂之后, 体积并不能恢复到原来的状态导致电池体 积膨胀, 使得电极出现粉化, 失去电化学活性, 从而导致容量损失, 同时存在 极大安全隐患。 发明内容
「一种具备高功率、 高能量、 低自放电率的锂电池; 本发明的另一目的在于提供所述锂电池的制备
为实现上述目的, 本发明釆取的技术方案为: 一种锂电池, 包括正极片、 负极集流基体、 介于所述正极片和负极集流基体之间的隔离膜、 电解液;
所述正极片包括正极集流体、 附着在所述正极集流体上含有正极活性材料 的正极膜片、 焊接在所述正极集流体上的正极极耳;
所述负极集流基体包括负极集流体、 焊接在所述负极集流体上的负极极耳; 所述负极集流基体为由厚度为 6〜25 μ ιη的金属箔材或金属网制成的、 厚度 为 6 ~ 60 μ m具有平面或凹凸结构的集流基体;
所述电解液包含锂盐和溶剂, 所述锂盐为六氟磷酸锂, 且所述电解液中锂 盐的浓度为 1.5〜7mol/L。
上述所述具有平面或凹凸结构的金属箔材或金属网, 通过辊压或模压形成 凹凸结构的负极集流基体。 集流体, 在充电过程中, 正极活性材料中的锂脱出, 并沉积在负极集流基体表 面, 形成金属锂负极活性材料; 同时通过充电方式, 使正极活性材料中的锂脱 出, 形成正极活性材料。 从而实现在充电过程利用电镀的方式在其负极集流基 体表面镀上一层薄薄的金属锂层, 节省了锂电池空间, 提高了锂电池的能量密 度和功率密度。 同时 凸结构金属箔材或金属网能够提供集流体伸缩的空间, 以及提供电解液保持空间, 避免负极集流体由于镀锂体积膨胀而导致正负极集 流体断裂, 同时提高电池中电解液的保有量。 所述电解液与现有常规电解液体 系相比, 本发明所述锂电池的电解液为高锂盐浓度电解液体系, 具有高的阴阳 离子浓度, 高的锂离子迁移数有利于锂离子的快速迁移, 从而利于锂在负极表 面沉积; 同时, 高锂盐浓度电解液体系具有较高的粘度, 有效避免了由于金属 锂沉积不均勾所带来的金属锂枝晶产生 (高锂离子浓度有利于负极金属锂的均 匀生长, 有利于降低金属锂负极表面由于阴离子耗尽所产生的空间电荷层, 从 而降低了金属锂非均勾沉积的电场驱动力; 高粘度体系在一定程度上增加了锂 枝晶生长的阻力), 使得沉积在负极金属箔材上的金属锂均匀、 致密的生长, 稳 定性和安全性大大提高。 作为本发明所述锂电池的优选实施方式, 所述正极集流体为厚度 12〜25 μ ιη 的铝箔。 作为本发明所述锂电池的优选实施方式, 所述正极活性材料为能够可逆的 嵌入和脱出锂离子的嵌锂化合物。 作为本发明所述锂电池的更优选实施方式, 所述正极活性材料为钴酸锂、 锰酸锂、 镍钴锰酸锂、 磷酸铁锂、 富锂多元材料 中的至少一种。 本发明所述正极活性材料优选但不限于钴酸锂、 锰酸锂、 镍钴 锰酸锂、 磷酸铁锂、 富锂多元材料中的至少一种, 本领域技术人员可根据需要 选择其他能够可逆的嵌入和脱出锂离子的嵌锂化合物作为正极活性材料。 作为本发明所述锂电池的优选实施方式, 上述所述金属箔材为铝箔、 锡箔、 镍箔或铜箔, 所述金属网为铝网、 锡网、 镍网或铜网。 本发明所述负极集流基 体优选但不限于由铝箔、 锡箔、 镍箔、 铜箔、 铝网、 锡网、 镍网或铜网形成, 本领域技术人员可根据实际情况及需要选择其他金属箔材或金属网作为负极集 流基体。 作为本发明所述锂电池的优选实施方式, 所述隔离膜为聚丙烯 /聚乙烯 /聚丙 烯三层隔膜、 或聚丙烯单层隔膜、 或聚乙烯单层隔膜、 或表面涂覆有金属氧化 物的聚丙烯或聚乙烯隔膜。 作为本发明所述锂电池的优选实施方式, 所述电解液中的溶剂包括碳酸乙 烯酯、 碳酸曱乙酯、 碳酸二曱酯和添加剂。 作为本发明所述锂电池的优选实施方式, 所述碳酸乙烯酯、 碳酸曱乙酯、 碳酸二曱酯的质量比为 1 : 1 : 1。 作为本发明所述锂电池的优选实施方式, 所述添加剂为曱基膦酸二曱酯、 乙基碑酸二乙酯中的至少一种。 当所述添加剂为曱基膦酸二曱酯、 乙基碑酸二 乙酯中的至少一种时, 使得本发明所述锂电池的电解液中含有具有阻燃效果的 溶剂, 能够有效改善电池的安全性能。 所述电解液为添加有阻燃溶剂的双功能 高锂盐浓度电解液体系时, 同时解决了锂离子快速迁移和稳定了负极锂层的两 项问题。 作为本发明所述锂电池的优选实施方式, 所述添加剂的含量占溶剂总质量 的 5〜25%。 所述添加剂的含量太少, 不能很好的起到阻燃效果, 本申请发明人 经过大量试验研究得出, 所述添加剂的含量优选为占溶剂总质量的 5〜25%, 这 样能够艮好的改善电池的安全性能。 同时, 本发明的另一目的在于提供一种上述所述锂电池的制备方法, 为实 现此目的, 本发明釆取的技术方案为: 一种如上所述锂电池的制备方法, 包括 以下步骤:
( 1 )正极片的制作: 将正极活性材料制成正极浆料, 并将正极浆料均匀涂 覆在正极集流体上, 得到附着有包含正极活性材料的正极膜片的正极集流体, 将附着有正极膜片的正极集流体冷压后裁切, 并焊接正极极耳, 得到正极片;
( 2 ) 负极集流基体的制作: 在负极集流体上焊接负极极耳, 得到负极集流 基体;
( 3 ) 隔离膜的制作: 按照一定的长度和宽度裁切得到隔离膜; ( 4 ) 电解液的制作: 将锂盐加入到溶剂中, 制得电解液;
( 5 )锂电池的制作: 将正极片、 隔离膜和负极集流基体制成锂电池电芯, 然后将电芯装入包装壳中注入电解液后封口;
( 6 )锂电池的化成及老化: 将步骤(5 )制得的锂电池化成老化后进行成 型, 即得锂电池。
极活性材料与聚偏二氟乙烯粘结剂和导电碳在 N-曱基吡咯烷酮溶剂中搅拌均 匀, 制成正极浆料。
叠片或卷绕工艺将正极片、 隔离膜和负极集流基体制成锂电池电芯。 优选地, 釆用叠片或卷绕工艺将正极片、 隔离膜和负极极流基体制成锂电池电芯, 所述 锂电池电芯的结构以及所述叠片或卷绕工艺均与现有技术相同。
电池的化成老化流程为 0.05〜0.2C 电流充电至 4.0V后用 0.2〜1C 电流充电至 4.2V, 并在 40〜50°C环境中老化 24〜72h。 本发明所述锂电池的制备方法中, 所 述锂电池首次化成流程为 0.05 ~ 0.2C电流充电至 4.0V后用 0.2 ~ 1C电流充电至 4.2V, 小的充电电流使得从正极材料中脱出的 Li+緩慢沉积在负极集流体铜箔上 形成均勾致密的锂层, 提高了电池的安全性。 另外, 本发明的再一目的在于提供一种如上所述锂电池在电子设备中的用 途。 本发明所述锂电池具有高功率、 高能量、 低自放电率的特性, 可满足电子 设备功能不断升级的需求, 因而可广泛应用于电子设备中, 例如本发明所述锂 电池优选但不限于作为电子烟电池。 本发明的用途并非限于此, 此处仅为举例 说明。 本发明所述锂电池, 与现有常规锂离子电池的不同之一在于所述负极为具 有平面或凹凸结构的集流基体, 并在其表面镀有一层金属锂层, 具体是在充电 过程中利用电镀的方式在负极集流体上镀上一层薄薄的致密金属锂层, 并在放 电过程中金属锂以 Li+的形式嵌入正极材料中, 同时凹凸结构金属箔材或金属网 能够提供集流体伸缩的空间, 以及提供电解液保持空间, 避免负极集流体由于 镀锂体积膨胀而导致正负极集流体断裂, 并且这种凹凸结构能够提高电池中电 解液的保有量; 与现有常规锂离子电池的不同之二所述电解液为高锂盐浓度电 解液体系, 具有高的阴阳离子浓度, 高的锂离子迁移数有利于锂离子的快速迁 移, 解决了金属锂的快速迁移难题; 同时, 高锂盐浓度电解液体系具有较高的 粘度, 有效避免了由于金属锂沉积不均匀所带来的金属锂枝晶产生 (高锂离子 浓度有利于负极金属锂的均勾生长, 有利于降低金属锂负极表面由于阴离子耗 尽所产生的空间电荷层, 从而降低了金属锂非均匀沉积的电场驱动力; 高粘度 体系在一定程度上增加了锂枝晶生长的阻力), 使得沉积在负极金属箔材上的金 属锂均勾、 致密的生长, 稳定性和安全性大大提高。 本发明所述锂电池与现有技术相比, 具有如下优势:
( 1 ) 高能量密度: 由于本发明锂电池所述电芯结构中负极集流基体厚度为 6-25μηι的金属箔材, 这给锂电池节省了空间, 能够增加正极的装载量, 提高锂 电池的能量密度;
( 2 ) 高功率密度: 本发明锂电池利用电镀的方式, 在锂电池充电过程中, 正极材料脱出 Li+并沉积在负极集流体上形成一层薄薄的锂层, 基于金属箔材作 为集流体和锂沉积的方式, 不仅提高极片的抗拉强度而且提高锂离子的快速迁 移能力, 从而提高功率密度;
( 3 ) 高安全性: 常规低盐浓度电解液在充电过程中, 正极脱出的 Li+在负 极沉积形成多孔疏松的锂层, 甚至是锂枝晶, 容易刺破隔膜导致电池短路; 而 本发明电解液为添加有阻燃溶剂的双功能高锂盐浓度电解液体系, 其具有较高 的粘度, 有效避免了由于金属锂沉积不均匀所带来的金属锂枝晶生产, 使得沉 积在负极铜箔上的金属锂均匀、 致密的生长, 稳定性和安全性大大提高; 同时 负极为具有 凸结构的金属箔材或金属网, 其能够提供集流体伸缩的空间, 避 免负极集流体由于镀锂体积膨胀而导致正负极集流体断裂, 安全性大大提高;
( 4 )低自放电率: 本发明具有与一次电池类似的结构, 具有极低的自放电 率。 本发明所述锂电池的制备方法操作简单便捷, 能够制备得到结合了一次锂 电池高能和可充电锂离子电池高功率的特点, 大大提高了锂电池的能量密度和 功率密度, 且具有极低的自放电率。 本发明所述锂电池具有高功率、 高能量、 低自放电率的特性, 能够满足电子设备功能不断升级的需求, 可广泛应用于电 子设备中。 附图说明 图 1为本发明所述锂电池中负极集流基体的一种实施例的截面结构示意图。 图 2为本发明所述锂电池中负极集流基体的另一实施例的截面结构示意图。 图 3为本发明实施例 1、 对比例 1和对比例 2锂电池在 100mA的放电曲线 对比图。 图 4为本发明实施例 1、对比例 1和对比例 2锂电池在 1000mA的放电曲线 对比图。 图 5为本发明实施例 1、 对比例 1和对比例 2锂电池的体积比能量对比图。 具体实施方式 为更好的说明本发明的目的、 技术方案和优点, 下面将结合附图和具体实 施例对本发明作进一步说明。 实施例 1 本发明锂电池的一种实施例, 本实施例所述锂电池釆用以下方法制备而成: ( 1 )正极片的制作: 以克容量为 140mAh/g的钴酸锂 ( LiCo02 ) 为正极活 性材料, 与粘结剂 PVDF和导电剂 Super-P按 95: 2: 3的质量比在 NMP中混 合搅拌均匀, 制成正极浆料, 按 33.0mg/cm2的密度将正极浆料双面涂覆在厚度 为 16μιη、 长度为 168mm的铝箔上, 所述正极浆料在铝箔上双面涂覆的长度分 别为 130mm和 152mm, 经冷压裁切成宽度为 42mm、 厚度为 0.107mm的极片, 并焊接正极极耳得到表面附着有正极膜片的正极片; (2) 负极集流基体的制作: 取 9μιη的铜箔裁切成长度为 153mm、 宽度为 44mm的铜箔,通过辊压或模压形成厚度为 20μιη并具有凹凸结构的负极集流体, 结构如附图 1所示, 并在集流体上焊接负极极耳, 得到负极集流基体;
(3)隔离膜的制作:釆用厚度为 16μιη的聚丙烯 /聚乙烯 /聚丙烯(ΡΡ/ΡΕ/ΡΡ) 三层隔离膜, 长度为 320mm、 宽度为 46mm;
( 4 )电解液的制作: 将六氟碑 S史锂 ( LiPF6 )加入到溶剂中, 混合均匀得到 电解液, 其中, 所述溶剂为碳酸乙烯酯 (EC)、 碳酸曱乙酯(EMC)、 碳酸二曱 酯( DMC )和曱基碑酸二曱酯( DMMP )的混合液,所述溶剂中碳酸乙烯酯( EC )、 碳酸曱乙酯 (EMC)、 碳酸二曱酯(DMC) 的质量比 EC:EMC:DMC=1:1:1, 曱 基碑酸二曱酯 (DMMP) 的质量占溶剂总质量的 10%, 所得电解液中六氟碑酸 锂(LiPF6) 的浓度为 5mol/L;
(5)锂电池的制作: 将上述得到的正极片、 隔离膜和负极集流基体进行卷 绕得到锂电池电芯, 然后将电芯装入铝塑膜包装壳中并注入电解液后封口;
(6)锂电池的化成及老化: 用 13mA ( 0.05C ) 的电流将将步骤(5)制得 的锂电池充电至 4.0V, 再用 52mA (0.2C) 的电流充电至 4.2V, 然后将锂电池 于 45°C烤箱中老化 48h后成型得到本发明实施例 1型号为 68500的锂电池。 实施例 2 本发明锂电池的一种实施例, 本实施例所述锂电池釆用以下方法制备而成: ( 1 ) 正极片 的制作: 以克容量为 146mAh/g 的镍钴锰酸锂 ( LiNi。.4Co。.2Mn。.402 )为正极活性材料, 与粘结剂 PVDF和导电剂 Super-P按 94.5: 2: 3.5的质量比在 NMP中混合搅拌均匀, 制成正极浆料, 按 30.0mg/cm2 的密度将正极浆料双面涂覆在厚度为 16μιη、 长度为 168mm的铝箔上, 所述正 极浆料在铝箔上双面涂覆的长度分别为 130mm和 152mm,经冷压裁切成宽度为 42mm,厚度为 0.107mm的极片,并焊接正极极耳得到表面附着有正极膜片的正 极片;
(2) 负极集流基体的制作: 取 9μιη的锡箔裁切成长度为 153mm、 宽度为 44mm的锡箔,通过辊压或模压形成厚度为 25μιη并具有凹凸结构的负极集流体, 结构如附图 2所示, 并在集流体上焊接负极极耳, 得到负极集流基体;
(3)隔离膜的制作:釆用厚度为 16μιη的聚丙烯 /聚乙烯 /聚丙烯(ΡΡ/ΡΕ/ΡΡ) 三层隔离膜, 长度为 320mm、 宽度为 46mm;
( 4 )电解液的制作: 将六氟碑 S史锂 ( LiPF6 )加入到溶剂中, 混合均匀得到 电解液, 其中, 所述溶剂为碳酸乙烯酯 (EC )、 碳酸曱乙酯(EMC )、 碳酸二曱 酯 ( DMC )和乙基碑酸二乙酯 ( DEEP )的混合液,所述溶剂中碳酸乙烯酯 ( EC )、 碳酸曱乙酯 (EMC )、 碳酸二曱酯(DMC ) 的质量比 EC:EMC:DMC=1:1: 1 , 乙 基碑 S史二乙酯(DEEP ) 的质量占溶剂总质量的 5%, 所得电解液中六氟碑 S史锂 ( LiPF6 ) 的浓度为 7mol/L;
( 5 )锂电池的制作: 将上述得到的正极片、 隔离膜和负极集流基体进行卷 绕得到锂电池电芯, 然后将电芯装入铝塑膜包装壳中并注入电解液后封口;
( 6 )锂电池的化成及老化: 用 50mA ( 0.2C )的电流将将步骤(5 )制得的 锂电池充电至 4.0V, 再用 250mA ( 1C ) 的电流充电至 4.2V, 然后将锂电池于 50°C烤箱中老化 36h后成型得到本发明实施例 2型号为 68500的锂电池。 实施例 3 本发明锂电池的一种实施例, 本实施例所述锂电池釆用以下方法制备而成: ( 1 )正极片的制作: 以克容量为 lOOmAh/g的锰酸锂 ( LiMn02 )为正极活 性材料, 与粘结剂 PVDF和导电剂 Super-P按 94.5: 2: 3.5的质量比在 NMP中 混合搅拌均匀, 制成正极浆料, 按 27.0mg/cm2的密度将正极浆料双面涂覆在厚 度为 16μιη、 长度为 168mm的铝箔上, 所述正极浆料在铝箔上双面涂覆的长度 分别为 130mm和 152mm, 经冷压裁切成宽度为 42mm、 厚度为 0.102mm的极 片, 并焊接正极极耳得到表面附着有正极膜片的正极片;
( 2 ) 负极集流基体的制作: 取 16μιη的铝箔裁切成长度为 153mm、 宽度为 44mm的铝箔,通过辊压或模压形成厚度为 5050μιη并具有凹凸结构的负极集流 体, 结构如附图 1所示, 并在集流体上焊接负极极耳, 得到负极集流基体;
( 3 )隔离膜的制作:釆用厚度为 16μιη的聚丙烯 /聚乙烯 /聚丙烯(ΡΡ/ΡΕ/ΡΡ ) 三层隔离膜, 长度为 320mm、 宽度为 46mm;
( 4 )电解液的制作: 将六氟碑 S史锂 ( LiPF6 )加入到溶剂中, 混合均匀得到 电解液, 其中, 所述溶剂为碳酸乙烯酯 (EC )、 碳酸曱乙酯(EMC )、 碳酸二曱 酯(DMC )、 曱基磷酸二曱酯(DMMP )和乙基磷酸二乙酯(DEEP )的混合液, 所述溶剂中碳酸乙烯酯(EC )、 碳酸曱乙酯(EMC )、 碳酸二曱酯(DMC )的质 量比 EC:EMC:DMC=1: 1:1,曱基磷酸二曱酯( DMMP )和乙基磷酸二乙酯( DEEP ) 的质量比 DMMP: DEEP= 1:1, 曱基碑酸二曱酯 ( DMMP )和乙基碑酸二乙酯 (DEEP)的质量和占溶剂总质量的 20%, 所得电解液中六氟碑 S史锂(LiPF6)的 浓度为 1.5mol/L;
(5)锂电池的制作: 将上述得到的正极片、 隔离膜和负极集流基体进行卷 绕得到锂电池电芯, 然后将电芯装入铝塑膜包装壳中并注入电解液后封口;
(6)锂电池的化成及老化: 用 15mA (0.1C)的电流将将步骤(5)制得的 锂电池充电至 4.0V, 再用 75mA (0.5C) 的电流充电至 4.2V, 然后将锂电池于 40°C烤箱中老化 72h后成型得到本发明实施例 3的锂电池。 实施例 4 本发明锂电池的一种实施例, 本实施例所述锂电池釆用以下方法制备而成: ( 1 )正极片的制作: 以克容量为 140mAh/g的钴酸锂 ( LiCo02 )和克容量 为 lOOmAh/g的锰酸锂 ( LiMn02 ) 的混合物为正极活性材料, 与粘结剂 PVDF 和导电剂 Super-P按 95: 2: 3的质量比在 NMP中混合搅拌均匀,制成正极浆料, 按 28mg/cm2的密度将正极浆料双面涂覆在厚度为 12μιη、长度为 168mm的铝箔 上,所述正极浆料在铝箔上双面涂覆的长度分别为 130mm和 152mm,经冷压裁 切成宽度为 42mm、 厚度为 0.102mm的极片, 并焊接正极极耳得到表面附着有 正极膜片的正极片;
(2) 负极集流基体的制作: 取 25μιη的镍网裁切成长度为 153mm、 宽度为 44mm的镍网,通过辊压或模压形成厚度为 60μιη并具有凹凸结构的负极集流体, 结构如附图 2所示, 并在集流体上焊接负极极耳, 得到负极集流基体;
( 3 )隔离膜的制作:釆用厚度为 12μιη的聚丙烯单层隔离膜,长度为 320mm、 宽度为 46mm;
( 4 )电解液的制作: 将六氟碑 S史锂 ( LiPF6 )加入到溶剂中, 混合均匀得到 电解液, 其中, 所述溶剂为碳酸乙烯酯 (EC)、 碳酸曱乙酯(EMC)、 碳酸二曱 酯(DMC)、 曱基磷酸二曱酯(DMMP)和乙基磷酸二乙酯(DEEP)的混合液, 所述溶剂中碳酸乙烯酯(EC)、 碳酸曱乙酯(EMC)、 碳酸二曱酯(DMC)的质 量比 EC:EMC:DMC=1: 1:1,曱基磷酸二曱酯( DMMP )和乙基磷酸二乙酯( DEEP ) 的质量比 DMMP: DEEP= 1:1, 曱基碑酸二曱酯 ( DMMP )和乙基碑酸二乙酯 (DEEP)的质量和占溶剂总质量的 25%, 所得电解液中六氟碑 S史锂(LiPF6)的 浓度为 4mol/L;
(5)锂电池的制作: 将上述得到的正极片、 隔离膜和负极集流基体进行叠 片得到锂电池电芯, 然后将电芯装入铝塑膜包装壳中并注入电解液后封口;
(6)锂电池的化成及老化: 用 13mA ( 0.05C ) 的电流将将步骤(5)制得 的锂电池充电至 4.0V, 再用 52mA (0.2C) 的电流充电至 4.2V, 然后将锂电池 于 48°C烤箱中老化 24h后成型得到本发明实施例 4的锂电池。 实施例 5 本发明锂电池的一种实施例, 本实施例所述锂电池釆用以下方法制备而成: ( 1 ) 正极片 的制作: 以克容量为 146mAh/g 的镍钴锰酸锂 ( LiNio.4Coo.2Mno.4O2 )为正极活性材料,与粘结剂 PVDF和导电剂 Super-P按 95: 2: 3的质量比在 NMP中混合搅拌均匀, 制成正极浆料, 按 32mg/cm2的密度将 正极浆料双面涂覆在厚度为 25μιη、 长度为 168mm的铝箔上, 所述正极浆料在 铝箔上双面涂覆的长度分别为 130mm和 152mm, 经冷压裁切成宽度为 42mm、 厚度为 0.107mm的极片, 并焊接正极极耳得到表面附着有正极膜片的正极片;
(2) 负极集流基体的制作: 取 6μιη的铝网裁切成长度为 153mm、 宽度为 44mm的铝网,本实施例所形成的负极集流体为厚度 6μιη具有平面结构的铝网, 并在集流体上焊接负极极耳, 得到负极集流基体;
( 3 )隔离膜的制作:釆用厚度为 14μιη的聚乙烯单层隔离膜,长度为 320mm、 宽度为 46mm;
( 4 )电解液的制作: 将六氟碑 S史锂 ( LiPF6 )加入到溶剂中, 混合均匀得到 电解液, 其中, 所述溶剂为碳酸乙烯酯 (EC)、 碳酸曱乙酯(EMC)、 碳酸二曱 酯( DMC )和曱基碑酸二曱酯( DMMP )的混合液,所述溶剂中碳酸乙烯酯( EC )、 碳酸曱乙酯 (EMC)、 碳酸二曱酯(DMC) 的质量比 EC:EMC:DMC=1:1:1, 曱 基碑酸二曱酯 (DMMP) 的质量和占溶剂总质量的 15%, 所得电解液中六氟磷 酸锂 ( LiPF6 ) 的浓度为 6mol/L;
(5)锂电池的制作: 将上述得到的正极片、 隔离膜和负极集流基体进行叠 片得到锂电池电芯, 然后将电芯装入铝塑膜包装壳中并注入电解液后封口;
(6)锂电池的化成及老化: 用 50mA ( 0.2C )的电流将将步骤(5)制得的 锂电池充电至 4.0V, 再用 250mA ( 1C ) 的电流充电至 4.2V, 然后将锂电池于 42°C烤箱中老化 60h后成型得到本发明实施例 5的锂电池。 对比例 1 本发明锂电池的一种对比例, 本对比例所述锂电池釆用以下方法制备而成: ( 1 )正极片的制作: 以克容量为 140mAh/g的钴酸锂 ( LiCo02 ) 为正极活 性材料, 与粘结剂 PVDF和导电剂 Super-P按 95: 2: 3的质量比在 NMP中混 合搅拌均匀, 制成正极浆料, 按 28.0mg/cm2的密度将正极浆料双面涂覆在厚度 为 16μιη、 长度为 120mm的铝箔上, 所述正极浆料在铝箔上双面涂覆的长度分 别为 82mm和 100mm, 经冷压裁切成宽度为 42mm、 厚度为 0.093mm极片, 并 焊接正极极耳得到表面附着有正极膜片的正极片;
(2) 负极片的制作: 以克容量为 350mAh/g的石墨为负极活性材料, 与粘 结剂丁苯橡胶(SBR)、 增稠剂羧曱基纤维素 (CMC)和导电剂 Super-P按 95: 1.8: 1.5: 1.7的质量比在去离子水中混合搅拌均匀,制成负极浆料,以 12.4mg/cm2 的密度按双面涂覆长度均为 100mm的尺寸将负极浆料双面涂覆在厚度为 9μιη、 长度为 105mm的铜箔上, 经冷压裁切成宽度为 44mm、 厚度为 0.09mm的极片, 并焊接负极极耳得到表面附着有负极膜片的负极片;
(3)隔离膜的制作:釆用厚度为 16μιη的聚丙烯 /聚乙烯 /聚丙烯(PP/PE/PP) 三层隔离膜, 长度为 265mm、 宽度为 46mm;
(4)电解液的制作: 将六氟碑 S史锂(LiPF6)加入到溶剂中, 混合均匀得到 电解液, 其中, 所述溶剂为碳酸乙烯酯 (EC)、 碳酸曱乙酯 (EMC)和碳酸二 曱酯(DMC) 的混合液, 所述溶剂中碳酸乙烯酯(EC)、 碳酸曱乙酯(EMC)、 碳酸二曱酯 ( DMC ) 的质量比 EC :EMC :DMC= 1:1:1, 所得电解液中六氟碑 S史锂
( LiPF6 ) 的浓度为 lmol/L;
(5)锂电池的制作: 将上述得到的正极片、 隔离膜和负极片进行卷绕得到 锂电池电芯, 然后将电芯装入铝塑膜包装壳中并注入电解液后封口;
(6)锂电池的化成及老化: 用 13mA (0.1C)的电流将将步骤(5)制得的 锂电池充电至 4.0V, 再用 52mA (0.4C)的电流充电至 4.2V, 成型得到对比例 1 型号为 68500的锂电池。 对比例 2 本发明锂电池的一种对比例, 本对比例所述锂电池釆用以下方法制备而成: ( 1 )正极片的制作: 以克容量为 270mAh/g的二氧化锰( Mn02 )为正极活 性材料, 与粘结剂 PVDF和导电剂 Super-P和 KS-6按 90: 3: 3.5:3.5的质量比 在 NMP中混合搅拌均勾, 制成正极浆料, 按 28.0mg/cm2的密度将正极浆料双 面涂覆在厚度为 16μιη、 长度为 120mm的铝箔上, 所述正极浆料在铝箔上双面 涂覆的长度分别为 82mm 和 100mm, 经冷压裁切成宽度为 44mm、 厚度为 0.108mm的极片, 并焊接正极极耳得到表面附着有正极膜片的正极片;
( 2 ) 负极片的制作: 取宽度为 42mm、 厚度为 0.07mm的锂带裁切成长度 为 95mm锂片, 并在锂片上冲压负极极耳, 得到负极片;
( 3 )隔离膜的制作:釆用厚度为 16μιη的聚丙烯 /聚乙烯 /聚丙烯(PP/PE/PP ) 三层隔离膜, 长度为 230mm, 宽度为 46mm;
( 4 )电解液的制作: 将六氟碑 S史锂 ( LiPF6 )加入到溶剂中, 混合均匀得到 电解液, 其中, 所述溶剂为碳酸乙烯酯 (EC )、 碳酸曱乙酯 (EMC )和碳酸二 曱酯(DMC ) 的混合液, 所述溶剂中碳酸乙烯酯(EC )、 碳酸曱乙酯(EMC )、 碳酸二曱酯 ( DMC ) 的质量比 EC :EMC :DMC= 1:1:1 , 所得电解液中六氟碑 S史锂 ( LiPF6 ) 的浓度为 lmol/L;
( 5 )锂电池的制作: 将上述得到的正极片、 隔离膜和负极片进行卷绕得到 锂电池电芯, 然后将电芯装入铝塑膜包装壳中并注入电解液后封口;
( 6 )锂电池的化成及老化: 用 13mA ( 0.05C ) 的电流将将步骤(5 )制得 的锂电池放电 12min (容量的 1% ), 然后将锂电池在 45 °C烤箱中老化 48h后成 型得到对比例 2型号为 68500的锂电池。 实施例 6 将上述实施例 1-5制备得到的锂电池分别进行 100mA和 1000mA放电, 其 放电容量、 平台电压如表 1所示: 表 1 放电截止电 1000mA 放 1000mA 放 100mA放电 100mA放电 组别
压 电中值电压 电容量 中值电压 容量 实施例 1 3.0 V 3.754 V 243.8 mAh 3.907 V 258.9 mAh 实施例 2 3.0 V 3.566 V 225.9 mAh 3.785 V 248.2 mAh 实施例 3 3.0 V 3.766 V 136.9 mAh 3.895 V 148.0 mAh 实施例 4 3.0 V 3.826 V 245.7 mAh 3.951 V 261.7 mAh 实施例 5 3.0 V 3.592 V 227.4 mAh 3.801 V 251.6 mAh 将上述实施例 1、 对比例 1和对比例 2制备得到的锂电池分别进行 100mA 和 1000mA放电和储存测试, 其放电容量、 平台电压和自放电率如表 2所示: 表 2
Figure imgf000015_0001
本发明实施例 1、 对比例 1和对比例 2制得的锂电池在 100mA和 1000mA 放电曲线图分别如附图 3和附图 4所示, 根据实施例 1和对比例 1、 2选取电池 型号计算实施例 1、 对比例 1和对比例 2电池的体积比能量如图 5所示。 由上述表 1和表 2数据及附图 3、 4和 5可以看出, 与对比例 1的锂离子电 池和对比例 2 的一次锂电池对比, 本发明制得的锂电池同时具备了一次锂电池 高能量和锂离子电池高功率的特性, 在充电过程正极脱出的 Li+在其负极集流体 表面沉积形成一层薄薄的金属锂层, 提高电池的功率密度, 同时负极不需涂覆 膜片而节省了电池空间提高了电池的体积能量密度; 另外, 本发明电解液为含 有阻燃溶剂的双功能高锂盐浓度电解液体系, 同时解决了锂离子快速迁移和稳 定了负极锂层的两项问题。 利用本发明方法所制备的锂电池, 结合了一次锂电 池高能量和锂离子电池高功率的特点, 大大提高了电池的能量密度和功率密度, 且具有极低的自放电率。 可作为一次电池或低循环要求的锂离子电池使用。 最后所应当说明的是, 以上实施例仅用以说明本发明的技术方案而非对本 发明保护范围的限制, 尽管参照较佳实施例对本发明作了详细说明, 本领域的 普通技术人员应当理解, 可以对本发明的技术方案进行修改或者等同替换, 而 不脱离本发明技术方案的实质和范围。

Claims

权 利 要 求 书
1、 一种锂电池, 其特征在于, 包括正极片、 负极集流基体、 介于所述正极 片和负极集流基体之间的隔离膜、 电解液;
所述正极片包括正极集流体、 附着在所述正极集流体上含有正极活性材料 的正极膜片、 焊接在所述正极集流体上的正极极耳;
所述负极集流基体包括负极集流体、 焊接在所述负极集流体上的负极极耳; 所述负极集流基体为由厚度为 6〜25 μ ιη的金属箔材或金属网制成的、 厚度 为 6 ~ 60 μ m具有平面或凹凸结构的集流基体;
所述电解液包含锂盐和溶剂, 所述锂盐为六氟磷酸锂, 且所述电解液中锂 盐的浓度为 1.5〜7mol/L。
2、如权利要求 1所述的锂电池,其特征在于,所述正极集流体为厚度 12-25 μ ιη的铝箔。
3、 如权利要求 1所述的锂电池, 其特征在于, 所述正极活性材料为能够可 逆的嵌入和脱出锂离子的嵌锂化合物。
4、如权利要求 3所述的锂电池, 其特征在于, 所述正极活性材料为钴酸锂、 锰酸锂、 镍钴锰酸锂、 磷酸铁锂、 富锂多元材料中的至少一种。
5、 如权利要求 1所述的锂电池, 其特征在于, 所述金属箔材为铝箔、锡箔、 镍箔或铜箔, 所述金属网为铝网、 锡网、 镍网或铜网。
6、 如权利要求 1所述的锂电池, 其特征在于, 所述隔离膜为聚丙烯 /聚乙烯 /聚丙烯三层隔膜、 或聚丙烯单层隔膜、 或聚乙烯单层隔膜、 或表面涂覆有金属 氧化物的聚丙烯或聚乙烯隔膜。
7、 如权利要求 1所述的锂电池, 其特征在于, 所述电解液中的溶剂包括碳 酸乙烯酯、 碳酸曱乙酯、 碳酸二曱酯和添加剂。
8、 如权利要求 7所述的锂电池, 其特征在于, 所述碳酸乙烯酯、 碳酸曱乙 酯、 碳酸二曱酯的质量比为 1 : 1 : 1。
9、 如权利要求 7所述的锂电池, 其特征在于, 所述添加剂为曱基膦酸二曱 酯、 乙基碑 S史二乙酯中的至少一种。
10、 如权利要求 7或 9所述的锂电池, 其特征在于, 所述添加剂的含量占 溶剂总质量的 5〜25%。
11、 一种如权利要求 1-10任一所述锂电池的制备方法, 其特征在于, 包括 以下步骤;
( 1 )正极片的制作: 将正极活性材料制成正极浆料, 并将正极浆料均匀涂 覆在正极集流体上, 得到附着有包含正极活性材料的正极膜片的正极集流体, 将附着有正极膜片的正极集流体冷压后裁切, 并焊接正极极耳, 得到正极片;
( 2 ) 负极集流基体的制作: 在负极集流体上焊接负极极耳, 得到负极集流 基体;
( 3 ) 隔离膜的制作: 按照一定的长度和宽度裁切得到隔离膜;
( 4 ) 电解液的制作: 将锂盐加入到溶剂中, 制得电解液;
( 5 )锂电池的制作: 将正极片、 隔离膜和负极集流基体制成锂电池电芯, 然后将电芯装入包装壳中注入电解液后封口;
( 6 )锂电池的化成及老化: 将步骤(5 )制得的锂电池化成老化后进行成 型, 即得锂电池。
12、 如权利要求 11 所述锂电池的制备方法, 其特征在于, 所述步骤(1 ) 中将正极活性材料与聚偏二氟乙烯粘结剂和导电碳在 N-曱基吡咯烷酮溶剂中搅 拌均勾, 制成正极浆料。
13、 如权利要求 11 所述锂电池的制备方法, 其特征在于, 所述步骤(5 ) 中釆用叠片或卷绕工艺将正极片、 隔离膜和负极集流基体制成锂电池电芯。
14、 如权利要求 11 所述锂电池的制备方法, 其特征在于, 所述步骤(6 ) 中对锂电池的化成老化流程为 0.05〜0.2C电流充电至 4.0V后用 0.2〜1C电流充电 至 4.2V, 并在 40〜50°C环境中老化 24〜72h。
15、 如权利要求 1-10任一所述锂电池在电子设备中的用途。
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