WO2020063740A1 - 一种正极极片、使用该正极极片的锂离子电池、电池模块、电池包及装置 - Google Patents

一种正极极片、使用该正极极片的锂离子电池、电池模块、电池包及装置 Download PDF

Info

Publication number
WO2020063740A1
WO2020063740A1 PCT/CN2019/108134 CN2019108134W WO2020063740A1 WO 2020063740 A1 WO2020063740 A1 WO 2020063740A1 CN 2019108134 W CN2019108134 W CN 2019108134W WO 2020063740 A1 WO2020063740 A1 WO 2020063740A1
Authority
WO
WIPO (PCT)
Prior art keywords
positive electrode
active material
electrode active
electrode sheet
dielectric layer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/CN2019/108134
Other languages
English (en)
French (fr)
Inventor
曾毓群
梁成都
盛长亮
黄华锋
黄起森
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Contemporary Amperex Technology Co Ltd
Original Assignee
Contemporary Amperex Technology Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Contemporary Amperex Technology Co Ltd filed Critical Contemporary Amperex Technology Co Ltd
Priority to EP19866720.6A priority Critical patent/EP3787068B1/en
Priority to US17/057,062 priority patent/US12074315B2/en
Publication of WO2020063740A1 publication Critical patent/WO2020063740A1/zh
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G53/00—Compounds of nickel
    • C01G53/40—Complex oxides containing nickel and at least one other metal element
    • C01G53/42—Complex oxides containing nickel and at least one other metal element containing alkali metals, e.g. LiNiO2
    • C01G53/44—Complex oxides containing nickel and at least one other metal element containing alkali metals, e.g. LiNiO2 containing manganese
    • C01G53/50—Complex oxides containing nickel and at least one other metal element containing alkali metals, e.g. LiNiO2 containing manganese of the type (MnO2)n-, e.g. Li(NixMn1-x)O2 or Li(MyNixMn1-x-y)O2
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H01M4/1315—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx containing halogen atoms, e.g. LiCoOxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/364—Composites as mixtures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00—Batteries for particular applications
    • H01M2220/20—Batteries in motive systems, e.g. vehicle, ship, plane
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present application relates to a positive pole piece, a lithium ion battery using the positive pole piece, a battery module, a battery pack, and a device.
  • Lithium-ion batteries have broad application prospects in the field of electric vehicles due to their high energy density, long cycle life, and no pollution. In order to meet the consumers' requirements for the mileage of electric vehicles, it is one of the effective methods to develop positive active materials with high specific capacity.
  • lithium-nickel-cobalt-manganese ternary materials have become hotspots for research due to their higher theoretical specific capacity and safety characteristics.
  • the high nickel metal content of lithium-nickel-cobalt-manganese ternary materials makes them highly oxidative, leading to The electrolyte is prone to electrochemical oxidation reactions on the surface of the positive electrode, and at the same time, it will cause changes in the structure of the lithium-nickel-cobalt-manganese ternary material.
  • the transition reactions of nickel, cobalt, and other transition metals will dissolve and cause the deterioration of the electrochemical performance of lithium-ion batteries. It is obvious that the high temperature performance deteriorates.
  • the lithium nickel cobalt manganese ternary material will add an excess of lithium salt during the preparation process to compensate for the lithium loss caused by the sintering process. In this way, a small amount of Li residue will exist on the surface of the prepared positive electrode active material, which will Li 2 O exists in the form of Li 2 O.
  • Li 2 O will adsorb CO 2 and H 2 O in the air to form residual lithium such as LiOH and Li 2 CO 3.
  • the existence of these residual lithium will aggravate the lithium ion battery.
  • the gas production deteriorates storage performance.
  • Lithium nickel cobalt manganese ternary materials are usually in the form of secondary particles formed by primary particle agglomeration. The compressive strength is poor.
  • the specific surface area of the positive electrode active material after crushing increases significantly, resulting in an increase in the contact area with the electrolyte. Gas production problems have further worsened.
  • lithium-ion batteries are required to have a long cycle life and storage life. The longer cycle life and storage life are to make the battery have a longer range.
  • lithium-ion batteries are also required to have stable acceleration and power performance. This requires lithium-ion batteries to have low internal resistance during long-term cycling and storage.
  • an object of the present application is to provide a positive electrode sheet, a lithium ion secondary battery using the positive electrode sheet, a battery module, a battery pack, and a device.
  • the lithium-ion secondary battery of the present application has a lower gas production amount, prolongs the cycle life and storage life of the lithium-ion battery, and significantly suppresses the increase of the DC internal resistance of the lithium-ion battery during the cycle and storage process.
  • the present application provides a positive electrode sheet including a positive electrode current collector and a positive electrode active material layer disposed on at least one surface of the positive electrode current collector.
  • the positive electrode active material layer includes a formula ( 1) The positive electrode active material shown,
  • M is selected from one or two of Mn and Al, Me is selected from one of Zr, Zn, Cu, Cr, Mg, Fe, V, Ti, Y, Nb Or several, A is selected from one or more of N, F, S, Cl; at least one surface of the positive electrode active material layer away from the current collector is provided with an inorganic dielectric layer without a binder, said The resistance R of the positive pole piece is not higher than 8ohm.
  • the present application provides a lithium-ion battery including a positive electrode sheet, a negative electrode sheet, a separator, and an electrolyte according to the first aspect of the present application.
  • the separator is disposed on the positive electrode sheet and the negative electrode. Between the pole pieces.
  • the present application provides a battery module including the lithium ion battery described in the second aspect of the present application.
  • the present application provides a battery pack including the battery module described in the third aspect of the present application.
  • the present application provides a device including the lithium ion battery according to the second aspect of the present application, and the lithium ion battery is used as a power source of the device.
  • the device includes a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, and an energy storage system.
  • An inorganic dielectric layer without a binder is provided on the surface of the positive electrode sheet of the present application. Because the inorganic dielectric layer has good chemical stability, it can exist stably under high voltage. On the one hand, it can slow down the high-capacity positive electrode active material. Changes in the surface structure of the active material caused by excessive voltage increase the stability and long-term reliability of the positive electrode material; on the other hand, the above-mentioned inorganic dielectric layer can effectively suppress side reactions in the electrolyte on the surface of the positive electrode sheet and avoid strong The oxidizing positive electrode active material is in direct contact with the separator, thereby reducing the gas production of the lithium ion battery and avoiding the failure of the polymer of the separator under high voltage oxidation.
  • the inorganic layer material is a dielectric material with a certain degree of electrical insulation and ions.
  • the conduction performance by controlling the resistance of the positive pole piece to not higher than 8ohm, is conducive to ensuring that the internal resistance of the battery is low, the polarization is small, and the cycle performance and rate performance are good.
  • the battery module, the battery pack, and the device of the present application include the lithium-ion battery, and thus have at least the same advantages as the lithium-ion battery.
  • FIG. 1 is a schematic structural diagram of a specific positive electrode sheet in an embodiment of the present application.
  • FIG. 2 is a schematic structural diagram of another specific positive electrode sheet in the embodiment of the present application.
  • FIG. 3 is a schematic structural diagram of another specific positive electrode sheet in the embodiment of the present application.
  • FIG. 4 is a perspective view of an embodiment of a lithium ion battery.
  • FIG. 5 is an exploded view of FIG. 4.
  • FIG. 6 is a perspective view of an embodiment of a battery module.
  • FIG. 7 is a perspective view of an embodiment of a battery pack.
  • FIG. 8 is an exploded view of FIG. 7.
  • FIG. 9 is a schematic diagram of an embodiment of a device using a lithium ion battery as a power source.
  • connection means more than two (including two) unless explicitly stated and defined otherwise; unless otherwise specified or stated, the term “connected” shall be understood in a broad sense, for example, The “connection” may be a fixed connection, a detachable connection, or an integral connection, or an electrical connection, or a signal connection; the “connection” may be a direct connection or an indirect connection through an intermediate medium.
  • connection may be a fixed connection, a detachable connection, or an integral connection, or an electrical connection, or a signal connection; the “connection” may be a direct connection or an indirect connection through an intermediate medium.
  • a positive electrode sheet which includes a positive electrode current collector and a positive electrode active material layer provided on at least one surface of the positive electrode current collector, the positive electrode active material layer including the following formula (1) Positive active material:
  • M is selected from one or two of Mn and Al
  • Me is selected from one of Zr, Zn, Cu, Cr, Mg, Fe, V, Ti, Y, Nb
  • A is selected from one or more of N, F, S, Cl.
  • An inorganic dielectric layer is provided on at least one surface of the positive electrode active material layer remote from the current collector, and the inorganic dielectric layer does not contain a binder.
  • the resistance R of the positive electrode piece is not higher than 8 ohm.
  • FIGS. 1 to 3 The schematic diagram of the structure of the positive electrode sheet in the embodiment of the present application is shown in FIGS. 1 to 3.
  • the positive electrode current collector 521a is provided with a positive electrode active material layer 521b on one surface, and the positive electrode active material layer 521b is provided with an inorganic dielectric layer 521c on the surface.
  • a positive electrode active material layer 521b is provided on both surfaces of the positive electrode current collector 521a, and in the positive electrode sheet shown in FIG. 2, both positive electrode active material layers 521b are provided on the surface Inorganic dielectric layer 521c;
  • only one positive electrode active material layer 521b is provided with an inorganic dielectric layer 521c.
  • the positive electrode active material is a ternary positive electrode material with a higher gram capacity but strong oxidation, and a layer of a non-binder-containing inorganic medium is provided on the surface of the positive electrode active material layer.
  • the electric layer can effectively stabilize the structure of the active material on the surface of the positive electrode sheet and avoid the dissolution of transition metal ions.
  • the inorganic layer has electrochemical stability, thereby reducing The direct contact area between the positive electrode active material particles and the electrolyte is reduced, the side reaction of the electrolyte on the surface of the positive electrode sheet is reduced, and the storage gas generation problem of the lithium ion battery is effectively improved.
  • the inorganic dielectric layer and the positive electrode active material layer are not fixed by a binder, so the inorganic dielectric layer is avoided due to uneven distribution of the binder, immersion failure in the electrolyte, long-term cycling process, or mechanical abuse. Poor electrical performance and safety issues due to fall off.
  • the above-mentioned inorganic dielectric layer is tightly coated on the surface of the active particles on the surface of the positive electrode active material layer, which can reduce the probability of breakage of the positive electrode active material particles during the cycling process, so that the overall mechanical strength of the positive electrode active material layer is increased and it is not easy to break.
  • the above-mentioned inorganic dielectric layer can also form a chemically stable insulating interface between the strongly oxidizing positive electrode sheet and the separator, thereby preventing the polymer on the surface layer of the separator and the strong oxidizing positive active material layer from oxidizing and failing. .
  • the inorganic dielectric layer on the surface of the positive electrode active material layer in the present application is an inorganic dielectric material, so the resistance of the positive electrode sheet is increased.
  • the resistance of the positive pole piece accounts for about 80% of the internal resistance of the battery, so the internal resistance is too large, which will affect its energy output, battery life, and safety performance.
  • the resistance of the positive electrode sheet containing the inorganic dielectric layer is not higher than 8 ohm, which can improve the stability and safety performance of the battery system, and control the internal resistance of the battery system not to increase excessively, so that the battery has a good Dynamic performance and rate performance.
  • the resistance R of the positive electrode piece is the resistance of the positive electrode piece measured when the direct current two-probe method is used and the contact area between the probe and the positive electrode piece is 49 ⁇ mm 2 .
  • the upper and lower sides of the positive pole piece are clamped between two conductive terminals of the pole piece resistance tester, and pressure is applied to fix the resistance R of the positive pole piece.
  • the diameter of the conductive terminal is 14 mm, The applied pressure is 15 MPa to 27 MPa.
  • the pole piece resistance tester is, for example, a BT3562 internal resistance tester.
  • the inorganic dielectric layer may be formed by a vapor deposition method or an electrochemical deposition method.
  • the inorganic dielectric layer is formed by a vapor deposition method.
  • the vapor deposition method may be chemical vapor deposition, physical vapor deposition, or plasma vapor deposition.
  • the binding force of the inorganic dielectric layer and the positive electrode active material layer formed by the vapor deposition method is stronger, which can avoid the problem of the inorganic dielectric layer falling off the surface of the positive electrode active material layer during long-term cycling of the battery and when subjected to mechanical abuse.
  • the matrix of the positive electrode active material may be selected from LiNi 0.8 Co 0.1 Mn 0.1 O 2 , LiNi 0.70 Co 0.15 Mn 0.15 O 2 , LiNi 0.95 Co 0.02 Mn 0.03 O 2 , LiNi 0.8 Co 0.1 Al 0.1 O 2 , One or more of LiNi 0.70 Co 0.15 Mn 0.15 O 1.8 F 0.2 , LiNi 0.8 Co 0.1 Mn 0.08 Zr 0.02 O 2 , LiNi 0.75 Co 0.15 Mn 0.05 Nb 0.05 O 2 .
  • the positive electrode active material layer further includes a positive electrode active material represented by formula (2),
  • the positive electrode active material represented by the formula (2) has a spinel structure. Compared with the compound of the formula (1), the positive electrode active material represented by the formula (2) has good structural stability at high temperature and high voltage. Mixing a certain amount of the compound of formula (2) in the material layer can reduce the contact area between the compound of formula (1) and the electrolyte inside the pole piece, and further improve the gas generation problem and cycle stability of the high-capacity battery.
  • a plurality of nanoclusters are densely formed in the inorganic dielectric layer by virtue of intermolecular forces.
  • a nano-cluster is a kind of nano-scale ultrafine particles. When several to hundreds of atoms and molecules are aggregated together, nano-scale ultra-fine particles can be formed. Such ultra-fine particles are called nano-clusters.
  • the distribution form of the inorganic dielectric layer on the surface of the pole piece, the structure of the film layer are closely related to the preparation method, and the process parameters. The applicant found that when the inorganic dielectric layer is formed by multiple nanoclusters that are closely packed by intermolecular forces, the film is formed. The layer has a higher density, more stable electrochemical properties, and can exist stably under high voltage.
  • the average particle diameter D 1 of the nano-cluster and the thickness T of the inorganic dielectric layer covering the surface of the positive electrode active material layer satisfy: 0.02 * T ⁇ D 1 ⁇ T.
  • the inorganic layer has good stability against oxidation and high voltage effects.
  • it can also ensure that the inorganic layer has good permeability.
  • Electrolyte wettability and ion transmittance are high, and the dynamic performance of cells and pole pieces is good.
  • the average particle diameter of the nanoclusters is 5 nm to 200 nm.
  • the lower limit of the average particle size of the nanoclusters can be 5nm, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, 55nm, 60nm, 65nm, 70nm, 75nm, 80nm, 85nm, 90nm, 95nm, 100nm.
  • the upper limit of the average particle size of the nanoclusters may be 110nm, 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm, 200nm.
  • the average particle diameter of the nanoclusters can be composed of any of the above upper and lower limits.
  • the thickness T of the inorganic dielectric layer is 50 nm to 1000 nm.
  • the upper limit of the thickness of the inorganic dielectric layer can be 1000nm, 990nm, 950nm, 900nm, 850nm, 800nm, 750nm, 720nm, 700nm, 680nm, 650nm, 600nm, 550nm, 500nm, 490nm, 450nm, 430nm, 400nm, 380nm, 350nm, 300nm , 280nm, 250nm, 200nm; the lower limit of the thickness of the inorganic dielectric layer may be 50nm, 55nm, 60nm, 65nm, 70nm, 75nm, 80nm, 85nm, 90nm, 95nm, 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, 160nm , 170nm, 180n
  • the thickness of the inorganic dielectric layer may be composed of any of the above upper and lower limits. If the inorganic dielectric layer is too thin, the interface between the positive electrode sheet and the electrolyte and the separator cannot be effectively stabilized. If the inorganic dielectric layer is too thick, the resistance of the positive electrode sheet will increase sharply on the one hand, and on the other hand, it will be on the positive electrode. A dense film layer is formed on the surface of the pole piece, which affects the cycle performance and dynamic performance of the battery, and also increases the thickness of the pole piece and reduces the energy density of the battery.
  • the thickness T of the inorganic dielectric layer is 100 nm to 600 nm, and further preferably, the thickness of the inorganic dielectric layer is 200 nm to 500 nm.
  • the strongly oxidizing surface of the positive electrode piece is effectively protected, the surface of the separator and the electrolyte are not easily oxidized, and the thickness and mass of the battery are less increased, which is conducive to improving the mass energy density and volume energy density of the battery .
  • the inorganic dielectric layer covers the surface of the outermost layer of the positive electrode active material layer and the inner wall of at least a part of the pores in the positive electrode active material layer in a discontinuous, sheet-like form.
  • the inorganic dielectric layer can be deposited not only on the surface of the positive electrode active material layer, but also on the inner wall of the pores between the active material particles at a certain depth on the surface of the positive electrode sheet. After the cold pressing process, the inorganic dielectric layer on the surface of the pole piece becomes a discontinuous sheet shape.
  • the above structure can make use of the high dielectric constant and hydrophilicity of the inorganic material to form an electrochemically stable protective layer on the surface of the positive electrode sheet to increase the electrode sheet's wetting rate to the electrolyte; at the same time, the inorganic dielectric layer is discontinuous
  • the shape distribution can avoid the too low density of the inorganic dielectric layer, which causes the porosity of the pole piece surface to be too low, and the ion channels to be reduced, resulting in poor cycling and dynamic performance of the local cell.
  • the thickness of the inorganic dielectric layer covering the inner wall of the pores inside the positive electrode active material layer gradually decreases from the outermost layer to the inside in the thickness direction of the positive electrode active material layer.
  • the gas phase method is used in the examples of the present application, as the thickness of the inorganic dielectric layer increases, the thickness of the inorganic dielectric layer deposited in the interstices of the active material layer gradually decreases in the thickness direction of the positive electrode active material layer, and the inside of the pole piece
  • the pore size is larger, the porosity is higher, the pore size of the outer layer of the pole piece is reduced, and the porosity is reduced.
  • the above structure can improve the wettability and liquid retention of the pole piece to the electrolyte, and suppress the electrolyte in the positive pole piece and internal active material The more obvious the effect of side reactions on the surface, the better the gas generation and safety performance of the cell.
  • the depth of the inorganic dielectric layer spreading in the thickness direction of the positive electrode active material layer is 1/1000 to 1/10 of the thickness of the positive electrode active material layer.
  • the propagation depth of the inorganic dielectric layer inside the positive electrode active material layer gradually deepens as the thickness of the deposition increases.
  • the diffusion depth of the inorganic dielectric layer inside the positive electrode active material layer is within the above range, it can be ensured that the surface and the inside of the active material layer have certain pores, the electrode sheet has good wettability to the electrolyte, and excellent ion conduction performance.
  • the inorganic dielectric layer may be Al oxide, AlO (OH), Al nitride, Al fluoride, Si oxide, Si nitride, Si Fluoride, Ti oxide, Ti nitride, Ti fluoride, Zn oxide, Zn nitride, Zn fluoride, Mg oxide, Mg nitride, Mg fluoride, Zr At least one of an oxide, a nitride of Zr, a fluoride of Zr, an oxide of Ca, a nitride of Ca, a fluoride of Ca, an oxide of Ba, an oxide of Ba, or a fluoride of Ba.
  • the compacted density of the positive electrode sheet is 3.2 g / cm 3 to 3.9 g / cm 3
  • the porosity of the positive electrode sheet is 2% to 30%.
  • the compacted density and porosity of the positive electrode sheet are within the above ranges, and it can be ensured that the inorganic dielectric layer formed on the surface of the electrode sheet is formed on the inner surface of the pores between the surface of the electrode sheet and some of the particles, and the thickness will not exceed Thickness caused the pole piece pores to be blocked.
  • the inorganic The dielectric layer enters the inside of the pole piece too much, and a good chemical passivation layer cannot be formed on the surface of the pole piece, so as to suppress the oxidative decomposition of the electrolyte and the separator.
  • the inorganic dielectric layer is almost distributed on the surface of the pole piece, and there is almost no coverage of the particles inside the pole piece, which is easy. Cause the surface pores to be blocked, reducing the ion conduction performance.
  • the particle diameter D50 of the substrate of the positive electrode active material may be 5 ⁇ m to 25 ⁇ m, and preferably, the particle diameter D50 of the substrate of the positive electrode active material may be 8 ⁇ m to 18 ⁇ m.
  • a specific surface area of the positive electrode active material is 0.3m 2 /g ⁇ 0.8m 2 / g.
  • the positive electrode active material layer further includes a binder and a conductive agent.
  • the specific types of the binder and the conductive agent are not specifically limited, and can be selected according to requirements.
  • the binder may be specifically selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene, vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene One or more of a terpolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, and a fluorine-containing acrylate resin.
  • the conductive agent may be specifically selected from one or more of conductive carbon black, superconducting carbon black, conductive graphite, acetylene black, Ketjen black, graphene, and carbon nanotubes.
  • the specific type of the positive electrode current collector is not specifically limited, and can be selected according to requirements.
  • the positive electrode current collector may be an aluminum foil.
  • a lithium ion battery which includes the positive electrode sheet, the negative electrode sheet, a separator, and an electrolyte according to the first aspect of the present application, wherein the separator is disposed between the positive electrode sheet and the negative electrode sheet. between.
  • FIG. 4 is a perspective view of an embodiment of the lithium ion battery 5.
  • FIG. 5 is an exploded view of FIG. 4. 4 to 5, the lithium ion battery 5 includes a case 51, an electrode assembly 52, and a top cover assembly 53.
  • the electrode assembly 52 is housed in the case 51.
  • the electrode assembly 52 includes a positive electrode piece 521, a negative electrode piece, and a separator.
  • the separator separates the positive electrode piece 521 and the negative electrode piece.
  • the electrolytic solution is injected into the case 51 and impregnates the electrode assembly 51, specifically, the positive electrode sheet 521, the negative electrode sheet, and the separator.
  • the number of the electrode assemblies 52 is not limited, and may be one or more.
  • the battery shown in FIG. 4 is a can-type battery, but is not limited thereto.
  • the lithium ion battery 5 may be a pouch-type battery, that is, the case 51 is replaced by a metal plastic film and the top cover assembly 53 is eliminated.
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer, and the negative electrode active material layer may be disposed on one surface of the negative electrode current collector or may be disposed on the negative electrode. Current collector on both surfaces.
  • the negative electrode active material may be selected from one or more of lithium metal, carbon-based negative electrode material, silicon-based material, tin-based material, and lithium titanate.
  • the carbon-based negative electrode material may be selected from one or more of natural graphite, artificial graphite, mesophase microcarbon spheres (MCMB for short), hard carbon, soft carbon nanocarbon, and carbon fiber;
  • the material may be selected from silicon, silicon-carbon composite, and silicon-oxygen compound;
  • the tin-based material may be selected from one or more of elemental tin, tin-oxygen compound, tin-carbon composite, and tin alloy.
  • a second inorganic layer containing no binder is provided on the surface of the negative electrode sheet, and the resistance of the negative electrode sheet is not higher than 3 ohm.
  • the properties of the second inorganic layer and the inorganic dielectric layer provided on the surface of the positive electrode active material layer are substantially the same. The above setting can further optimize the interface of the negative electrode sheet of the lithium ion battery without greatly increasing the precursor of the negative electrode resistance, and effectively stabilize the cycling and storage performance of the battery system under high voltage and high temperature.
  • the negative electrode active material layer further includes a binder and a conductive agent.
  • the specific types of the binder and the conductive agent are not specifically limited, and can be selected according to requirements.
  • the binder may be specifically selected from one or more of styrene-butadiene rubber (SBR) and sodium carboxymethyl cellulose (CMC).
  • the conductive agent may be specifically selected from one or more of conductive carbon black, superconducting carbon black, conductive graphite, acetylene black, Ketjen black, graphene, and carbon nanotubes.
  • the specific type of the negative electrode current collector is not specifically limited, and can be selected according to requirements.
  • the negative electrode current collector may be a copper foil.
  • the composition of the electrolytic solution is not specifically limited, and can be formulated according to actual needs.
  • the electrolyte includes a lithium salt, an organic solvent, and optional additives.
  • the type of the organic solvent is not specifically limited, and can be selected according to requirements.
  • the organic solvent may be selected from the group consisting of ethylene carbonate (EC), propylene carbonate, butene carbonate, fluoroethylene carbonate, ethyl methyl carbonate (EMC), dimethyl carbonate, and diethyl carbonate ( DEC), dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, 1,4-butyrolactone, methyl propionate, methyl butyrate, ethyl acetate, ethyl propionate, ethyl butyrate, At least two of sulfolane, dimethylsulfone, methylethylsulfone, and diethylsulfone.
  • the type of the lithium salt is not specifically limited, and can be selected according to requirements.
  • the lithium salt may be selected from one or more of LiPF 6 , LiBF 4 , LiClO 4 , LiAsF 6 , LiFSI, LiTFSI, LiTFS, LiPO 2 F 2 , LiDFOB, and LiBOB.
  • the concentration of the lithium salt is 0.5 mol / L to 1.5 mol / L; further preferably, the concentration of the lithium salt is 0.8 mol / L to 1.2 mol / L.
  • the electrolyte may further include vinylene carbonate (VC), ethylene ethylene carbonate (VEC), fluoroethylene carbonate (FEC), and succinonitrile (SN ), Adiponitrile (ADN), 1,3-propene sultone (PST), tris (trimethylsilane) phosphate (TMSP), tris (trimethylsilane) borate (TMSB) One or more.
  • VEC vinylene carbonate
  • VEC ethylene ethylene carbonate
  • FEC fluoroethylene carbonate
  • SN succinonitrile
  • Adiponitrile ADN
  • 1,3-propene sultone PST
  • TMSP tris (trimethylsilane) phosphate borate
  • TMSB tris (trimethylsilane) borate
  • the electrolytic solution may be prepared by a conventional method, for example, all materials in the electrolytic solution may be mixed uniformly.
  • lithium salt, additive A, and additive B are added to an organic solvent and mixed to obtain an electrolytic solution.
  • the order of adding the materials is not particularly limited.
  • a lithium salt can be added to an organic solvent, and then additive A and additive B can be simultaneously added and mixed uniformly to obtain an electrolytic solution.
  • the specific type of the separator is not specifically limited, and can be selected according to needs, for example, it can be selected from polyethylene, polypropylene, polyvinylidene fluoride, and the above-mentioned polyethylene, polypropylene,
  • the multilayer composite film of polyvinylidene fluoride is not limited to these. Barrier films made of these materials can be used for the isolation film, and coating treatment can also be performed on these bare films.
  • the coating varies depending on the conditions of the isolation film. For example, it can be a ceramic coating or an organic coating.
  • a battery module which includes the lithium-ion battery described in the second aspect of the present application.
  • FIG. 6 is a perspective view of an embodiment of the battery module 4.
  • the battery module 4 includes a plurality of lithium-ion batteries 5.
  • the plurality of batteries 5 are aligned in the longitudinal direction.
  • a battery pack which includes the battery module described in the third aspect of the present application.
  • FIG. 7 is a perspective view of an embodiment of the battery pack 1.
  • FIG. 8 is an exploded view of FIG. 7. 7 and 8, the battery pack 1 includes an upper case 2, a lower case 3, and a battery module 4.
  • the upper case 2 and the lower case 3 are assembled together to form a space for accommodating the battery module 4.
  • the battery module 4 is placed in the space of the upper case 2 and the lower case 3 assembled together.
  • the output electrode of the battery module 4 is penetrated from one or both of the upper case 2 and the lower case 3 to supply power to the outside or charge from the outside.
  • the number and arrangement of the battery modules 4 can be determined according to actual needs.
  • the present application provides a device including the lithium ion battery described in the second aspect of the present application, or the battery module described in the third aspect, or the battery pack described in the fourth aspect. .
  • the lithium-ion battery can be used as a power source of the device.
  • the device includes a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, and an energy storage system.
  • FIG. 9 is a schematic diagram of an embodiment of a device using a lithium ion battery as a power source.
  • the above battery module, battery pack, and device include the lithium-ion battery provided in the present application, and therefore have at least the same advantages as the lithium-ion battery, and will not be described in detail herein.
  • the lithium ion batteries of Examples 1-15 were all prepared according to the following method.
  • the positive electrode active material, the conductive agent Super P, and the binder polyvinylidene fluoride (PVDF) were mixed in a mass ratio of 97: 1.4: 1.6, and added to the solvent N-methylpyrrolidone (NMP), under the action of a vacuum mixer.
  • NMP solvent N-methylpyrrolidone
  • An inorganic dielectric layer is prepared on the surface of at least one diaphragm of the above-mentioned prepared positive electrode sheet by a plasma-assisted thermal evaporation deposition technique.
  • the heating source is an electron beam
  • the heating target is a corresponding elemental substance (such as Al, Si, Mg, etc.) other than oxygen in the inorganic layer.
  • an oxygen-containing activating gas such as oxygen, ozone, oxygen, etc.
  • control the temperature of the substrate to less than 100 ° C, and adjust the heating current (50A to 300A) and the vacuum degree of the process cavity (10 -1 to 10 -3 Pa), oxygen flow rate (100sccm-2000sccm), plasma power (300W-600W) and process time, adjust the deposition rate of the inorganic layer on the surface of the positive electrode sheet, and further adjust the thickness, composition and micromorphology of the inorganic layer.
  • the organic solvent is a mixed solution of ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC).
  • EC ethylene carbonate
  • EMC ethyl methyl carbonate
  • DEC diethyl carbonate
  • the volume ratio of EC, EMC, and DEC is 20:20:60.
  • an argon atmosphere glove box with a water content of ⁇ 10 ppm the sufficiently dried lithium salt was dissolved in the above organic solvent, and then additives were added and mixed uniformly to obtain an electrolytic solution.
  • the concentration of the lithium salt was 1 mol / L.
  • a 14 ⁇ m-thick polyethylene film (PE) substrate was coated with a 2 ⁇ m organic-inorganic particle composite coating on the surface as a release film.
  • the positive electrode, the separator and the negative electrode are stacked in order to make the separator between the positive and negative electrodes play a role of isolation, and then wound into a square bare cell, soldering the tabs,
  • the core is packed in a packaging aluminum-plastic film, and then baked at 80 ° C to remove water. Then, the electrolyte is injected and sealed, and then it is left to stand, hot and cold pressed, and formed (0.02C constant current charging to 3.3V, and then 0.1). C constant current charging to 3.6V), shaping, capacity testing and other procedures, to obtain the finished flexible packaging lithium-ion battery, which has a thickness of 4.0mm, a width of 60mm, and a length of 140mm.
  • Example 2 The difference from Example 2 is that the surface of the positive electrode sheet is not provided with an inorganic dielectric layer.
  • Example 2 The difference from Example 2 is that the thickness of the inorganic dielectric layer on the surface of the positive electrode sheet is 1200 nm.
  • Example 2 The difference from Example 2 is that the inorganic dielectric layer provided on the surface of the positive electrode sheet is a slurry containing a binder and alumina ceramic particles, which is coated on the surface of the positive electrode sheet to be used and cold-pressed. 2. Obtained after drying.
  • the volume expansion rate (%) of the lithium-ion battery after storage at 80 ° C for 360 h (V 1 -V 0 ) / V 0 ⁇ 100%.
  • the lithium-ion battery was subjected to a 1,000-cycle charge / discharge test according to the method described above. Each group tested 15 lithium-ion batteries and averaged.
  • Lithium-ion battery capacity retention rate after 1000 cycles at 45 ° C (%) discharge capacity after 1000 cycles / discharge capacity at the first cycle ⁇ 100%.
  • the capacity retention rate (%) of the lithium ion battery after storage at 60 ° C for 180 days C 180 / C 0 ⁇ 100%.
  • the DC internal resistance of the lithium ion battery after 1000 cycles at 45 ° C and the DC internal resistance after storage at 60 ° C for 180 days were calculated, and the DCR growth rate of the lithium ion battery was calculated.
  • the inorganic dielectric layer does not contain a binder on the positive electrode active material layer, and at the same time, the resistance of the positive electrode sheet does not exceed 8 ohm.
  • the inorganic dielectric layer has Good electrochemical stability, which can isolate the direct contact between the strong oxidizing positive electrode active material layer and the electrolyte.
  • the inorganic dielectric layer is arranged on the surface of the macroscopic positive electrode sheet, which can also reduce the surface roughness of the active material outside the positive electrode sheet.
  • the inorganic dielectric layer can also function as an insulating interface between the positive electrode sheet and the separator, preventing the separator polymer from oxidizing and failing in contact with the highly oxidizing positive electrode sheet under high voltage.
  • Comparative Example 1 the surface of the positive electrode active material layer was not provided with an inorganic dielectric layer.
  • the surface of the positive electrode had strong oxidizing properties, and the electrolyte had many side reactions on the surface of the electrode.
  • the volume expansion rate of the battery is high, the internal resistance increases significantly, and the capacity retention rate decreases significantly.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Inorganic Chemistry (AREA)
  • Materials Engineering (AREA)
  • Composite Materials (AREA)
  • Manufacturing & Machinery (AREA)
  • Organic Chemistry (AREA)
  • Secondary Cells (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

一种正极极片（521）、使用该正极极片（521）的锂离子电池（5）、电池模块（4）、电池包（1）及装置。所述锂离子电池（5），包括正极极片（521）、负极极片、隔离膜以及电解液。正极极片（521）包括正极集流体（521a）以及设置在正极集流体（521a）表面且含有正极活性材料的正极活性物质层（521b），在正极活性物质层（521b）表面设置有不含粘结剂的无机介电层（521c），正极极片（521）的电阻不高于8ohm。由于无机介电层（521c）良好的化学稳定性，在高电压下可以稳定存在，可以减缓正极活性材料因过高电压引起的活性物质表面结构变化，提高正极材料的稳定性，同时有效隔绝强氧化性的正极活性物质与电解液中稳定性较差的添加剂、溶剂以及隔离膜外表面直接接触，降低锂离子电池（5）的产气量，避免隔离膜表层聚合物在高电压下失效；正极极片（521）的电阻不高于8ohm有利于保证电池内阻较低、极化较小，循环性能和倍率性能较好。

Description

一种正极极片、使用该正极极片的锂离子电池、电池模块、电池包及装置
本申请要求于2018年09月29日提交中国专利局、申请号为201811151916.1、发明名称为“一种正极极片以及使用该正极极片的锂离子电池”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
本申请涉及一种正极极片、使用该正极极片的锂离子电池、电池模块、电池包及装置。
背景技术
锂离子电池由于具有能量密度高、循环寿命长、无污染等特点，使其在电动汽车领域具有广阔的应用前景。为了满足广大消费者对电动汽车续里程的要求，开发具有高比容量的正极活性材料是有效办法之一。
目前，锂镍钴锰三元材料由于具有较高的理论比容量和安全特性成为了研究的热点，然而锂镍钴锰三元材料中镍金属含量很高使得其具有很强的氧化性，导致电解液容易在正极表面发生电化学氧化反应，同时还会引起锂镍钴锰三元材料结构的变化，镍、钴等过渡金属发生还原反应而溶出，引起锂离子电池电化学性能的恶化，特别是高温性能明显恶化。此外，锂镍钴锰三元材料在制备过程中会加入过量锂盐来弥补烧结过程中造成的锂损失，这样在制得的正极活性材料表面都会存在少量的Li残余，其在高温下会以Li 2O的形式存在，当温度降低到室温以后，Li 2O会吸附空气中的CO 2和H 2O而形成LiOH和Li 2CO 3等残锂，这些残锂的存在会加剧锂离子电池的产气，恶化存储性能。锂镍钴锰三元材料通常是由一次颗粒团聚形成的二次颗粒形式，抗压强度较差，破碎后正极活性材料的比表面积显著增加，导致与电解液接触面积增大，锂离子电池的产气问题进一步恶化。
对电动汽车的应用而言，要求锂离子电池具有较长的循环寿命和存储寿命。较长的循环寿命和存储寿命是为了使电池具有更长的续航里程。此外，还要求锂离子电池具有稳定的加速性能和功率性能，这就要求锂离子电池还必须在长期的循环和存储过程中具有较低的内阻。
申请内容
鉴于背景技术中存在的问题，本申请的目的在于提供一种正极极片、使用该正极极片锂离子二次电池、电池模块、电池包及装置。本申请的锂离子二次电池具有较低的产气量，延长锂离子电池的循环寿命和存储寿命，并且显著抑制锂离子电池在循环和存储过程中直流内阻的增长。
为了达到上述目的，在本申请的第一方面，本申请提供了一种正极极片，包括正极集流体以及设置于正极集流体的至少一个表面的正极活性物质层，正极活性物质层包含式(1)所示的正极活性物质，
Li xNi yCo zM kMe pO rA m     式(1)
其中，0.95≤x≤1.05，0≤y≤1，0≤z≤1，0≤k≤1，0≤p≤0.1，y+z+k+p＝1，1≤r≤2，0≤m≤2，m+r≤2，M选自Mn、Al中的一种或两种，Me选自Zr、Zn、Cu、Cr、Mg、Fe、V、Ti、Y、Nb中的一种或几种，A选自N、F、S、Cl中的一种或几种；在正极活性物质层远离集流体的至少一个表面上设置有不含粘结剂的无机介电层，所述正极极片的电阻R不高于8ohm。
在本申请的第二方面，本申请提供了一种锂离子电池，其包括根据本申请第一方面的正极极片、负极极片、隔离膜以及电解液，隔离膜设置在正极极片和负极极片之间。
在本申请的第三方面，本申请提供了一种电池模块，其包括本申请的第二方面所述的锂离子电池。
在本申请的第四方面，本申请提供了一种电池包，其包括本申请的第三方面所述的电池模块。
在本申请的第五方面，本申请提供了一种装置，其包括本申请的第二方面所述的锂离子电池，所述锂离子电池用作所述装置的电源。
优选地，所述装置包括纯电动车、混合动力电动车、插电式混合动力电动车、电动自行车、电动踏板车、电动高尔夫球车、电动卡车、储能系统。
相对于现有技术，本申请至少包括如下所述的有益效果：
在本申请的正极极片表面设置有不含粘结剂的无机介电层，由于无机介电层具有良好的化学稳定性，在高电压下可以稳定存在，一方面可以减缓高容量正极活性材料在过高电压时引起的活性物质表面结构变化，提高正极材料的稳定性和长期可靠性；另一方面，上述无机介电层能有效抑制电解液中在正极极片表面的副反应、避免强氧化性的正极活性物质与隔离膜直接接触，从而降低锂离子电池的产气量、避免隔离膜聚合物在高电压下氧化失效；另外，无机层物质为介电材料、具有一定的电子绝缘和离子导通性能，通过控制正极极片的电阻不高于8ohm，有利于保证电池的内阻较低、极化较小，循环性能和倍率性能较好。
本申请的电池模块、电池包和装置包括所述的锂离子电池，因而至少具有与所述锂离子电池相同的优势。
附图说明
图1为本申请实施例中某一具体正极极片的结构示意图。
图2为本申请实施例中又一具体正极极片的结构示意图。
图3为本申请实施例中又一具体正极极片的结构示意图。
图4是锂离子电池的一实施方式的立体图。
图5是图4的分解图。
图6是电池模块的一实施方式的立体图。
图7是电池包的一实施方式的立体图。
图8是图7的分解图。
图9是锂离子电池用作电源的装置的一实施方式的示意图。
其中，附图标记说明如下：
1电池包
2上箱体
3下箱体
4电池模块
5电池
51壳体
52电极组件
521正极极片
521a正极集流体
521b正极活性材料层
521c无机介电层
53顶盖组件。
具体实施方式
为了使本申请的目的、技术方案及优点更加清楚明白，以下结合附图及实施例，对本申请进行进一步详细说明。应当理解，此处所描述的具体实施方式仅仅用以解释本申请，并不用于限定本申请。
在本申请的描述中，除非另有明确的规定和限定，术语“多个”是指两个以上(包括两个)；除非另有规定或说明，术语“连接”应做广义理解，例如，“连接”可以是固定连接，也可以是可拆卸连接，或一体地连接，或电连接，或信号连接；“连接”可以是直接相连，也可以通过中间媒介间接相连。对于本领域的普通技术人员而言，可以根据具体情况理解上述术语在本申请中的具体含义。
本说明书的描述中，需要理解的是，本申请实施例所描述的“上”、“下”等方位词是以附图所示的角度来进行描述的，不应理解为对本申请实施例的限定。下面通过具体的实施例并结合附图对本申请做进一步的详细描述。
下面详细说明根据本申请的正极极片、锂离子电池、电池模块、电池包及装置。
首先，说明根据本申请第一方面的正极极片，其包括正极集流体以及设置在正极集流体的至少一个表面上的正极活性物质层，所述正极活性物质层包含式(1)所示的正极活性物质：
Li xNi yCo zM kMe pO rA m       式(1)
其中，0.95≤x≤1.05，0≤y≤1，0≤z≤1，0≤k≤1，0≤p≤0.1，y+z+k+p＝1，1≤r≤2，0≤m≤2，m+r≤2，M选自Mn、Al中的一种或两种，Me选自Zr、Zn、Cu、Cr、Mg、Fe、V、Ti、Y、Nb中的一种或几种，A选自N、 F、S、Cl中的一种或几种。在所述正极活性物质层远离所述集流体的至少一个表面上设置有无机介电层，所述无机介电层不含粘结剂。所述正极极片的电阻R不高于8ohm。
本申请实施例的正极极片结构的示意图如图1～图3所示。在图1中，正极集流体521a的一个表面上设置有正极活性物质层521b，正极活性物质层521b的表面上设置有无机介电层521c。在图2和图3中，正极集流体521a的两个表面上均设置有正极活性物质层521b，在图2所示的正极极片中，两个正极活性物质层521b的表面上均设置有无机介电层521c；在图3所示的正极极片中，仅有一个正极活性物质层521b上设置有无机介电层521c。
在本申请第一方面的正极极片中，正极活性物质为克容量较高、但氧化性较强的三元正极材料，在上述正极活性物质层表面设置一层不含粘结剂的无机介电层，可以有效稳定正极极片表面活性材料的结构、避免过渡金属离子的溶出，同时，由于上述无机介电层主要是在正极极片表面，由于该无机层具有电化学稳定性，进而减少了正极活性物质颗粒与电解液的直接接触面积，降低电解液在正极极片表面的副反应，有效改善锂离子电池的存储产气问题。
上述无机介电层与正极活性物质层之间不是靠粘结剂固定，因此避免了因粘结剂分布不均、在电解液中浸泡失效、长期循环过程或者机械滥用情况下，无机介电层脱落引发的电性能变差以及安全问题。同时，上述无机介电层在正极活性物质层表面的活性颗粒表面紧密包覆，能够降低循环过程中正极活性材料颗粒破碎的概率，使得正极活性物质层整体的机械强度增加，不容易破碎。另外，上述无机介电层还可以在强氧化性的正极极片与隔离膜之间形成化学性质稳定的绝缘界面，避免隔离膜表层的聚合物与强氧化性的正极活性物质层接触氧化发生失效。
本申请中的正极活性物质层表面的无机介电层是一种无机介电材料，因此会增大正极极片的电阻。在电池体系中，正极极片的电阻占电池内阻的约80％，因此内阻过大，会影响其能量输出、电池寿命及安全性能。本申请中控制含有无机介电层的正极极片的电阻不高于8ohm，能够在提高电池体系稳定性以及安全性能的同时，控制电池体系的内阻不会过多地增加，使电池具有良好的动力学性能以及倍率性能。
正极极片的电阻R为采用直流两探针法且探针与正极极片的接触面积为49πmm 2时所测得的正极极片的电阻。作为一个示例，将正极极片的上下两侧夹持于极片电阻测试仪的两个导电端子之间，并施加压力以固定，测定正极极片的电阻R，其中导电端子的直径为14mm，施加压力为15MPa～27MPa。极片电阻测试仪例如为日置BT3562型内阻测试仪。
在本申请第一方面的正极极片中，所述无机介电层可以通过气相沉积法、电化学沉积形成。优选地，所述无机介电层通过气相沉积法形成。气相沉积法可为化学气相沉积、物理气相沉积或等离子体气相沉积。气相沉积法形成的无机介电层与正极活性物质层的结合力更强，可以避免电池长期循环过程中以及遭受机械滥用时无机介电层从正极活性物质层表面脱落的问题。
在本申请第一方面的正极极片中，优选地，在式(1)所示的正极活性物质中，0.50≤y≤0.95，0≤z≤0.2，0≤k≤0.2，0≤p≤0.05，且y+z+k+p＝1。进一步优选地，所述正极活性材料的基体可选自LiNi 0.8Co 0.1Mn 0.1O 2、LiNi 0.70Co 0.15Mn 0.15O 2、LiNi 0.95Co 0.02Mn 0.03O 2、LiNi 0.8Co 0.1Al 0.1O 2、LiNi 0.70Co 0.15Mn 0.15O 1.8F 0.2、LiNi 0.8Co 0.1Mn 0.08Zr 0.02O 2、LiNi 0.75Co 0.15Mn 0.05Nb 0.05O 2中的一种或几种。
在本申请第一方面的正极极片中，所述正极活性物质层还包含式(2)所示的正极活性物质，
Li 1+zMn cMe’ 2-cO 4-dA’ d      式(2)
其中，-0.1≤z≤0.2，0<c≤2，0≤d<1，Me’包括Ni、Fe、Cr、Ti、Zn、V、Al、Mg、Zr及Ce中的一种或多种，A’包括S、N、F、Cl、Br及I中的一种或多种。
式(2)所示的正极活性物质具有尖晶石结构，相对于式(1)化合物，式(2)所示的正极活性物质在高温高电压下具有良好的结构稳定性，因此在正极活性物质层中混合一定量的式(2)化合物，可以降低极片内部式(1)化合物与电解液的接触面积，进一步改善高容量电池的产气问题和循环稳定性。
在本申请第一方面的正极极片中，无机介电层中由多个纳米团簇依靠分子间作用力紧密堆积形成。纳米团簇是一种纳米尺度的超微粒子，将数个到数百个原子、分子凝聚在一起，就可以形成纳米尺度的超微粒子，这样的超 微粒子就称为纳米团簇。无机介电层在极片表面的分布形态、膜层结构与制备方法、工艺参数有着密切联系，本申请人发现无机介电层由多个纳米团簇依靠分子间作用力紧密堆积形成时，膜层的致密度较高、电化学性质更稳定，在高电压下能够稳定存在。
优选地，纳米团簇的平均粒径D 1与无机介电层在正极活性物质层表面覆盖的厚度T满足：0.02*T≤D 1≤T。从而满足纳米团簇的本身附着力、均一性并具有一定力学强度的要求，保证无机层具有良好的抗氧化、抗高电压效果的稳定性；同时还可以保证该无机层具有良好的通透性，电解液浸润性及离子透过率较高，电芯与极片的动力学性能良好。
在本申请第一方面的正极极片中，纳米团簇的平均粒径为5nm～200nm。纳米团簇平均粒径的下限可为5nm、10nm、15nm、20nm、25nm、30nm、35nm、40nm、45nm、50nm、55nm、60nm、65nm、70nm、75nm、80nm、85nm、90nm、95nm、100nm。纳米团簇平均粒径的上限可为110nm、120nm、130nm、140nm、150nm、160nm、170nm、180nm、190nm、200nm。纳米团簇的平均粒径可由上述上限或下限的任意数值组成。
在本申请第一方面的正极极片中，无机介电层的厚度T为50nm～1000nm。无机介电层厚度的上限可以为1000nm、990nm、950nm、900nm、850nm、800nm、750nm、720nm、700nm、680nm、650nm、600nm、550nm、500nm、490nm、450nm、430nm、400nm、380nm、350nm、300nm、280nm、250nm、200nm；无机介电层的厚度的下限可为50nm、55nm、60nm、65nm、70nm、75nm、80nm、85nm、90nm、95nm、100nm、110nm、120nm、130nm、140nm、150nm、160nm、170nm、180nm、190nm。无机介电层的厚度可由上述上限或下限的任意数值组成。如果无机介电层过薄，无法有效稳定正极极片与电解液、隔离膜的界面；如果无机介电层过厚，一方面会导致正极极片的电阻急剧增大，另一方面会在正极极片表面形成致密膜层，进而影响电池的循环性能和动力学性能，并且还会增加极片的厚度，降低电池能量密度。
优选地，无机介电层的厚度T为100nm～600nm，进一步优选地，无机介电层的厚度为200nm～500nm。在上述范围内，正极极片的强氧化性表面得到有效保护、隔离膜表面与电解液不易被氧化，而且对电池的厚度和质量增加较少，有利于提高电池的质量能量密度和体积能量密度。
在本申请第一方面的正极极片中，无机介电层以非连续、片层状的形态覆盖在正极活性物质层最外层的表面以及在正极活性物质层内部至少一部分孔隙的内壁上。本申请实施例中当采用气相法制备时，无机介电层不仅可以沉积在正极活性物质层的表面，还可以进一步沉积在正极极片表面一定深度的活性物质颗粒之间的孔隙内壁。经冷压处理后，极片表面的无机介电层变成非连续的片层形态。上述结构一方面可以利用无机材料的高介电常数和亲水性，在正极极片表面形成电化学稳定的保护层，提高极片对电解液的浸润速率；同时将无机介电层以非连续状分布，可以避免因无机介电层过于致密，导致极片表面的孔隙率过低、离子通道减少，导致局部电芯的循环性能和动力学性能变差。
优选地，无机介电层在正极活性物质层内部孔隙内壁覆盖的厚度，在正极活性物质层厚度方向由最外层向内部逐渐减小。本申请实施例中当采用气相法制备时，随着无机介电层厚度的增加，活性物质层内部颗粒间隙无机介电层沉积的厚度在正极活性物质层的厚度方向逐渐减小，极片内部的孔径较大、孔隙率较高，极片外层的孔径缩小、孔隙率降低，上述结构可以提高极片对电解液的浸润性和保液率，抑制电解液在正极极片和内部活性物质表面发生副反应的效果越明显，有效改善电芯的产气问题以及安全性能。
在本申请第一方面的正极极片中，无机介电层分布在正极活性物质层厚度方向上蔓延的深度为正极活性物质层厚度的1/1000～1/10。在具体的制备过程中，例如当采用气相沉积法时，无机介电层在正极活性物质层内部的蔓延深度随沉积厚度的提高逐渐加深。当无机介电层在正极活性物质层内部的蔓延深度在上述范围内时，可以保证活性物质层的表面及内部具有一定的孔隙，极片对电解液浸润性良好，离子导通性能优良。
在本申请第一方面的正极极片中，无机介电层可为Al的氧化物、AlO(OH)、Al的氮化物、Al的氟化物、Si的氧化物、Si的氮化物、Si的氟化物、Ti的氧化物、Ti的氮化物、Ti的氟化物、Zn的氧化物、Zn的氮化物、Zn的氟化物、Mg的氧化物、Mg的氮化物、Mg的氟化物、Zr的氧化物、Zr的氮化物、Zr的氟化物、Ca的氧化物、Ca的氮化物、Ca的氟化物、Ba的氧化物、Ba的氮化物、Ba的氟化物中的至少一种。
在本申请第一方面的正极极片中，所述正极极片的压实密度为 3.2g/cm 3～3.9g/cm 3，所述正极极片的孔隙率为2％～30％。本申请中正极极片的压实密度和孔隙率在上述范围内，可以保证形成在极片表面的无机介电层形成在极片表面以及内部一部分颗粒之间的孔隙内壁，并且厚度不会过厚而引起的极片孔隙被堵。当所述正极极片的压实密度过低(小于3.2g/cm 3)或者孔隙率过高(大于30％)时，由于极片表层及内部的孔隙过大过多，一方面会使得无机介电层进入极片内部过多，极片表面无法形成良好的化学钝化层，以抑制对电解液以及隔离膜的氧化分解。若极片的压实密度过高(大于3.9g/cm 3)或者孔隙率过低(小于2％)，无机介电层几乎都分布在极片表面，对极片内部颗粒几乎无覆盖，容易造成表面孔隙被堵，降低离子导通性能。
在本申请第一方面的正极极片中，正极活性材料的基体的粒径D50可为5μm～25μm，优选地，正极活性材料的基体的粒径D50可为8μm～18μm。
在本申请第一方面的正极极片中，所述正极活性材料的比表面积为0.3m 2/g～0.8m 2/g。
在本申请第一方面的正极极片中，所述正极活性物质层还包括粘接剂和导电剂。粘结剂和导电剂的具体种类均不受到具体的限制，可根据需求进行选择。优选地，所述粘结剂可具体选自聚偏氟乙烯(PVDF)、聚四氟乙烯、偏氟乙烯-四氟乙烯-丙烯三元共聚物、偏氟乙烯-六氟丙烯-四氟乙烯三元共聚物、四氟乙烯-六氟丙烯共聚物、含氟丙烯酸酯树脂中的一种或几种。优选地，所述导电剂可具体选自导电炭黑、超导炭黑、导电石墨、乙炔黑、科琴黑、石墨烯、碳纳米管中的一种或几种。
在本申请第一方面的正极极片中，正极集流体的具体种类不受到具体的限制，可根据需求进行选择。优选地，正极集流体可为铝箔。
其次说明根据本申请第二方面的锂离子电池，其包括根据本申请第一方面的正极极片、负极极片、隔离膜以及电解液，其中，隔离膜设置在正极极片和负极极片之间。
图4是锂离子电池5的一实施方式的立体图。图5是图4的分解图。参照图4至图5，锂离子电池5包括壳体51、电极组件52、顶盖组件53。电极组件52收容于壳体51内。电极组件52包括正极极片521、负极极片、隔离膜。隔离膜将正极极片521和负极极片隔开。电解液注入在壳体51内并浸渍 电极组件51，具体地浸渍正极极片521、负极极片以及隔离膜。在锂离子电池5中，电极组件52的数量不受限制，可以为一个或多个。
注意的是图4所示的电池为罐型电池，但不限于此，锂离子电池5可以是袋型电池，即壳体51由金属塑膜替代且取消顶盖组件53。
在本申请第二方面的锂离子电池中，所述负极极片包括负极集流体以及负极活性物质层，所述负极活性物质层可设置在负极集流体的其中一个表面上，也可以设置在负极集流体的两个表面上。其中，负极活性材料可选自金属锂、碳基负极材料、硅基材料、锡基材料、钛酸锂中的一种或几种。优选地，所述碳基负极材料可选自天然石墨、人造石墨、中间相微碳球(简写为MCMB)、硬碳、软碳纳米碳、碳纤维中的一种或几种；所述硅基材料可选自硅、硅-碳复合物、硅氧化合物；所述锡基材料可选自单质锡、锡氧化合物、锡碳复合物、锡合金中的一种或几种。
优选地，在负极极片的表面设置有不含粘结剂的第二无机层，所述负极极片的电阻不高于3ohm。所述第二无机层与设置在正极活性物质层表面的无机介电层的性质基本相同。上述设置可以在不过大增加负极电阻的前体下，进一步对锂离子电池的负极极片界面进行优化，有效稳定高电压、高温下电池体系的循环和存储性能。
在本申请第二方面的锂离子电池中，所述负极活性物质层还包括粘接剂和导电剂。粘结剂和导电剂的具体种类均不受到具体的限制，可根据需求进行选择。优选地，所述粘结剂可具体选自丁苯橡胶(SBR)、羧甲基纤维素钠(CMC)中的一种或几种。优选地，所述导电剂可具体选自导电炭黑、超导炭黑、导电石墨、乙炔黑、科琴黑、石墨烯、碳纳米管中的一种或几种。在本申请的锂离子电池中，负极集流体的具体种类不受到具体的限制，可根据需求进行选择。优选地，负极集流体可为铜箔。
在本申请第二方面的锂离子电池中，所述电解液的组成并不受到具体的限制，可以根据实际需求进行配制。通常，所述电解液包括锂盐、有机溶剂以及可选的添加剂。
在本申请第二方面的锂离子电池中，所述有机溶剂的种类没有具体的限制，可根据需求进行选择。优选地，所述有机溶剂可选自碳酸乙烯酯(EC)、碳酸丙烯酯、碳酸丁烯酯、氟代碳酸乙烯酯、碳酸甲乙酯(EMC)、碳酸二甲 酯、碳酸二乙酯(DEC)、碳酸二丙酯、碳酸甲丙酯、碳酸乙丙酯、1,4-丁内酯、丙酸甲酯、丁酸甲酯、乙酸乙酯、丙酸乙酯、丁酸乙酯、环丁砜、二甲砜、甲乙砜、二乙砜中的至少两种。
在本申请第二方面的锂离子电池中，所述锂盐的种类没有具体的限制，可根据需求进行选择。所述锂盐可选自LiPF 6、LiBF 4、LiClO 4、LiAsF 6、LiFSI、LiTFSI、LiTFS、LiPO 2F 2、LiDFOB以及LiBOB中的一种或几种。优选地，所述锂盐的浓度为0.5mol/L～1.5mol/L；进一步优选地，所述锂盐的浓度为0.8mol/L～1.2mol/L。
在本申请第二方面的锂离子电池中，所述电解液还可包括碳酸亚乙烯酯(VC)、碳酸乙烯亚乙酯(VEC)、氟代碳酸乙烯酯(FEC)、丁二腈(SN)、己二腈(ADN)、1,3-丙烯磺酸内酯(PST)、三(三甲基硅烷)磷酸酯(TMSP)、三(三甲基硅烷)硼酸酯(TMSB)中的一种或几种。
在本申请第二方面的锂离子电池中，电解液采用常规方法制备即可，比如将电解液中的各个物料混合均匀即可。例如，将锂盐、添加剂A、添加剂B加入到有机溶剂中进行混合，获得电解液。其中，各物料的添加顺序并没有特别的限制。例如，可先将锂盐加入到有机溶剂中，然后将添加剂A、添加剂B同时加入并混合均匀，获得电解液。
在本申请第二方面的锂离子电池中，隔离膜的具体种类没有具体的限制，可根据需求进行选择，例如可选自聚乙烯、聚丙烯、聚偏氟乙烯以及上述聚乙烯、聚丙烯、聚偏氟乙烯的多层复合膜，但不仅限于这些。隔离膜既可以使用这些材料制成的裸膜，也可以在这些裸膜上进行涂层处理，涂层因隔离膜使用条件的不同而不同，例如可为陶瓷涂层也可为有机物涂层。
在本申请的第三方面提供了一种电池模块，其包括本申请的第二方面所述的锂离子电池。
进一步，包括在电池模块中的锂离子电池的数量可以根据电池模块的应用和容量进行调节。图6是电池模块4的一实施方式的立体图。参照图6，电池模块4包括多个锂离子电池5。多个电池5沿纵向排列。
在本申请的第四方面提供了一种电池包，其包括本申请的第三方面所述的电池模块。图7是电池包1的一实施方式的立体图。图8是图7的分解图。参照图7和图8，电池包1包括上箱体2、下箱体3以及电池模块4。上箱体2和下箱体3组装在一起并形成收容电池模块4的空间。电池模块4置于组装在一起的上箱体2和下箱体3的空间内。电池模块4的输出极从上箱体2和下箱体3的其中之一或二者之间穿出，以向外部供电或从外部充电。电池模块4的数量和排列可以依据实际需要来确定。
在本申请的第五方面，本申请提供了一种装置，其包括本申请的第二方面所述的锂离子电池，或第三方面所述的电池模块，或第四方面所述的电池包。所述锂离子电池可以用作所述装置的电源。
作为本申请的一些优选实施方式，所述装置包括纯电动车、混合动力电动车、插电式混合动力电动车、电动自行车、电动踏板车、电动高尔夫球车、电动卡车、储能系统。图9是锂离子电池用作电源的装置的一实施方式的示意图。
上述电池模块、电池包和装置包括本申请提供的锂离子电池，因而至少具有与所述锂离子电池相同的优势，在此不再详细描述。
实施例1-15的锂离子电池均按照下述方法进行制备。
(1)正极极片制备
将步骤正极活性材料、导电剂Super P、粘结剂聚偏氟乙烯(PVDF)按照质量比97:1.4:1.6进行混合，加入至溶剂N-甲基吡咯烷酮(NMP)中，在真空搅拌机作用下搅拌均匀，获得正极浆料，其中正极浆料中固体含量为77wt％；将正极浆料均匀涂覆于正极集流体铝箔上并在85℃下烘干，然后经过冷压、切边、裁片、分条，最后继续在85℃的真空条件下烘干4h，得到待用正极极片。
在上述制备的待用正极极片的至少一个膜片表面，以等离子体辅助热蒸发沉积技术制备无机介电层。其中，加热源为电子束，加热靶材为无机层中除氧以外相应的元素单质(如Al、Si、Mg等)，在真空条件下，以含氧的活化气体(如氧气、臭氧、氧离子、一氧化氮、二氧化氮、二氧化碳、水蒸气等)为反应气体，控制基材温度小于100℃，通过调节加热电流 (50A～300A)、工艺腔真空度(10 -1～10 -3Pa)、氧流量(100sccm～2000sccm)、等离子体功率(300W～600W)以及工艺时间，调节无机层在正极极片表面的沉积速率，进一步调节无机层的厚度、组分和微观形貌。
实施例1-15正极极片的具体参数示出在表1中。
(2)负极极片制备
将负极活性材料、导电剂Super P、增稠剂羧甲基纤维素钠(CMC)、粘结剂丁苯橡胶乳液(SBR)按照质量比96.4:1.5:0.5:1.6进行混合，加入至溶剂去离子水中，在真空搅拌机作用下搅拌均匀，获得负极浆料，其中负极浆料中固体含量为54wt％；将负极浆料均匀涂覆在负极集流体铜箔上并在85℃下烘干，然后经过冷压、切边、裁片、分条，最后继续在120℃的真空条件下烘干12h，得到负极极片。
(3)电解液制备
有机溶剂为碳酸乙烯酯(EC)、碳酸甲乙酯(EMC)和碳酸二乙酯(DEC)的混合液，其中，EC、EMC和DEC的体积比为20:20:60。在含水量<10ppm的氩气气氛手套箱中，将充分干燥的锂盐溶解于上述有机溶剂中，然后加入添加剂，混合均匀，获得电解液。其中，锂盐的浓度为1mol/L。
(4)隔离膜的制备
以厚度为14μm的聚乙烯膜(PE)基材，表面涂敷2μm的有机-无机颗粒复合涂层作为隔离膜。
(5)锂离子电池的制备
将正极极片、隔离膜、负极极片按顺序叠好，使隔离膜处于正、负极极片之间起到隔离的作用，然后卷绕成方形的裸电芯，焊接极耳，将裸电芯装入包装箔铝塑膜中，然后在80℃下烘烤除水后，注入电解液并封口，之后经过静置、热冷压、化成(0.02C恒流充电到3.3V，再以0.1C恒流充电到3.6V)、整形、容量测试等工序，获得成品软包装锂离子电池，其厚度为4.0mm、宽度为60mm、长度为140mm。
对比例1
与实施例2不同之处在于，所述正极极片表面未设置无机介电层。
对比例2
与实施例2不同之处在于，所述正极极片表面无机介电层的厚度为 1200nm。
对比例3
与实施例2不同之处在于，所述正极极片表面设置的无机介电层是将含有粘结剂和氧化铝陶瓷颗粒的浆料，涂敷在待用正极极片表面，并经过冷压、烘干后处理得到的。
对比例1-3正极极片的具体参数示出在表1中。
表1实施例1-15和对比例1-3的正极极片参数
Figure PCTCN2019108134-appb-000001
接下来说明锂离子电池的测试过程。
(1)锂离子电池的80℃高温存储产气测试
在25℃下，将锂离子电池以0.5C恒流充电至电压为4.2V，之后以4.2V恒压充电至电流为0.05C，采用排水法测试此时锂离子电池的初始体积，并记为V 0，然后将锂离子电池放入80℃的恒温箱存储360h，存储结束后取出，再次采用排水法测试锂离子电池的体积，并记为V 1。每组测试15支锂离子电池，取平均值。
锂离子电池80℃存储360h后的体积膨胀率(％)＝(V 1-V 0)/V 0×100％。
(2)锂离子电池的45℃高温循环性能测试
在45℃下，将锂离子电池以1C恒流充电至4.2V，之后以4.2V恒压充电至电流为0.05C，然后以1C恒流放电至2.8V，此为一个充放电循环过程，此次的放电容量为首次循环的放电容量。将锂离子电池按照上述方法进行1000次循环充电/放电测试。每组测试15支锂离子电池，取平均值。
锂离子电池45℃循环1000次后的容量保持率(％)＝循环1000次的放电容量/首次循环的放电容量×100％。
(3)锂离子电池的60℃高温存储性能测试
在25℃下，将锂离子电池以0.5C恒流充电至4.2V，之后以4.2V恒压充电至电流为0.05C，然后以1C恒流放电至2.8V，得到初始放电容量C 0；之后将锂离子电池以0.5C恒流充电至4.2V，之后以4.2V恒压充电至电流为0.05C，将满充后的锂离子电池放入60℃的恒温箱保温180天，取出后测试锂离子电池的可逆容量，记为C 180。每组测试15支锂离子电池，取平均值。
锂离子电池60℃存储180天后的容量保持率(％)＝C 180/C 0×100％。
(4)锂离子电池循环和存储后的直流内阻(DCR)增长率测试
锂离子电池DCR测试过程为：在25℃时，调整锂离子电池的荷电状态(SOC)至满充容量的20％，以0.3C的倍率放电10s，放电前的电压记为U 1，放电后的电压记为U 2，则锂离子电池的初始直流内阻DCR 0＝(U 1-U 2)/I。
然后按照上述方法分别测试锂离子电池45℃循环1000次后的直流内阻以及60℃存储180天后的直流内阻，并计算锂离子电池的DCR增长率。每组测试15支锂离子电池，取平均值。
表2实施例1-15和对比例1-3的测试结果
Figure PCTCN2019108134-appb-000002
Figure PCTCN2019108134-appb-000003
通过上述实验结果可知，本申请实施例1-15中，通过在正极活性物质层上设置不含有粘结剂的无机介电层、同时保证正极极片的电阻不超过8ohm，无机介电层具有良好的电化学稳定性，可以隔绝强氧化性的正极活性物质层与电解液的直接接触，同时无机介电层设置在宏观的正极极片表面，还可以降低正极极片外侧活性物质的表面粗糙度，有效减少强氧化性的正极活性材料与电解液的有效接触面积，因此可以抑制电解液在正极极片表面的副反应，降低因电解液分解而产生的气体量，进而很好地延长电池的存储和使用寿命。另一方面，无机介电层还可以在正极极片和隔离膜之间起到绝缘界面的作用，避免在高电压下隔离膜聚合物与强氧化性的正极极片接触发生氧化而失效。
在对比例1中，正极活性物质层表面未设置无机介电层，在高温循环和存储的过程中，由于正极极片表面具有强氧化性，电解液在极片表面的副反应较多，因此电池的体积膨胀率较高，内部阻抗增加明显，容量保持率下降明显。
在对比例2和3中，尽管在正极活性物质层表面设置了无机介电层或者包含粘结剂的无机颗粒涂层，正极极片的界面得到了稳定，但是由于正极极片电阻过高，导致电池体系的内阻增加过多，因此电池的动力学性能以及倍率性能恶化。
以上所述，仅是本申请的几个实施例，并非对本申请做任何形式的限制，虽然本申请以较佳实施例揭示如上，然而并非用以限制本申请，任何熟悉本专业的技术人员，在不脱离本申请技术方案的范围内，利用上述揭示的技术内容做出些许的变动或修饰均等同于等效实施案例，均属于技术方案范围内。

Claims (15)

  1. 一种正极极片，包括正极集流体，以及设置在所述正极集流体的至少一个表面上的正极活性物质层，其特征在于：
    所述正极活性物质层包含式(1)所示的正极活性物质，
    Li xNi yCo zM kMe pO rA m  式(1)
    在所述式(1)中，0.95≤x≤1.05，0≤y≤1，0≤z≤1，0≤k≤1，0≤p≤0.1，y+z+k+p＝1，1≤r≤2，0≤m≤2，m+r≤2，M选自Mn、Al中的一种或两种，Me选自Zr、Zn、Cu、Cr、Mg、Fe、V、Ti、Y、Nb中的一种或几种，A选自N、F、S、Cl中的一种或几种；
    在所述正极活性物质层远离所述集流体的至少一个表面上设置有无机介电层，所述无机介电层不含粘结剂；
    所述正极极片的电阻R不高于8ohm。
  2. 根据权利要求1所述的正极极片，其特征在于，所述无机介电层由多个纳米团簇依靠分子间作用力紧密堆积形成，
    优选地，所述纳米团簇的平均粒径D 1与所述无机介电层在所述正极活性物质层表面覆盖的厚度T满足：0.02*T≤D 1≤0.5*T。
  3. 根据权利要求2所述的正极极片，其特征在于，所述纳米团簇的平均粒径D 1为5nm～200nm。
  4. 根据权利要求2所述的正极极片，其特征在于，所述无机介电层在所述正极活性物质层表面覆盖的厚度T为50nm～1000nm；
    优选地，所述无机介电层的厚度T为100nm～600nm；
    进一步优选地，所述无机介电层的厚度T为200nm～500nm。
  5. 根据权利要求1所述的正极极片，其特征在于，所述无机介电层非连续、片层状地覆盖在所述正极活性物质颗粒的表面，
    优选地，所述无机介电层还覆盖在所述正极活性物质层内部至少一部分 间隙的内壁上；
    进一步优选地，所述无机介电层在所述正极活性物质层内部间隙内壁覆盖的厚度，在所述正极活性物质层厚度方向由最外层向内部逐渐减小。
  6. 根据权利要求1所述的正极极片，其特征在于，所述无机介电层在所述正极活性物质层厚度方向蔓延的深度H为所述正极活性物质层厚度的1/1000～1/10。
  7. 根据权利要求1所述的正极极片，其特征在于，所述无机介电层中含有Al的氧化物、AlO(OH)、Al的氮化物、Al的氟化物、Si的氧化物、Si的氮化物、Si的氟化物、Ti的氧化物、Ti的氮化物、Ti的氟化物、Zn的氧化物、Zn的氮化物、Zn的氟化物、Mg的氧化物、Mg的氮化物、Mg的氟化物、Zr的氧化物、Zr的氮化物、Zr的氟化物、Ca的氧化物、Ca的氮化物、Ca的氟化物、Ba的氧化物、Ba的氮化物、Ba的氟化物中的至少一种。
  8. 根据权利要求1所述的正极极片，其特征在于，所述正极活性物质层还包含式(2)所示的正极活性物质，
    Li 1+zMn cMe’ 2-cO 4-dA’ d   式(2)
    所述式(2)中，-0.1≤z≤0.2，0<c≤2，0≤d<1，Me’包括Ni、Fe、Cr、Ti、Zn、V、Al、Mg、Zr及Ce中的一种或多种，A’包括S、N、F、Cl、Br及I中的一种或多种。
  9. 根据权利要求1所述的正极极片，其特征在于，所述正极极片的压实密度为3.2g/cm 3～3.9g/cm 3，所述正极极片的孔隙率为2％～30％。
  10. 根据权利要求1所述的正极极片，其特征在于，所述正极活性材料的平均粒径为5μm～25μm，比表面积为0.3m 2/g～0.8m 2/g。
  11. 一种锂离子电池，包括：如权1至10任一项所述的正极极片；负极极片；设置在正极极片和负极极片之间的隔离膜；以及电解液，所述电解液包括锂盐以及有机溶剂。
  12. 根据权利要求11所述的锂离子电池，其特征在于，在所述负极极片的表面设置有不含粘结剂的第二无机介电层，所述负极极片的电阻不高于3ohm。
  13. 一种电池模块，其特征在于，包括权利要求11至12中任一项所述的锂离子电池。
  14. 一种电池包，其特征在于，包括权利要求13所述的电池模块。
  15. 一种装置，其特征在于，包括权利要求11至12中任一项所述的锂离子电池，所述锂离子电池用作所述装置的电源；
    优选的，所述装置包括电动车辆、混合动力电动车辆、插电式混合动力电动车辆、电动自行车、电动踏板车、电动高尔夫球车、电动卡车、储能系统。
PCT/CN2019/108134 2018-09-29 2019-09-26 一种正极极片、使用该正极极片的锂离子电池、电池模块、电池包及装置 Ceased WO2020063740A1 (zh)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP19866720.6A EP3787068B1 (en) 2018-09-29 2019-09-26 Positive pole piece, and lithium ion battery, battery module, battery pack and device using positive pole piece
US17/057,062 US12074315B2 (en) 2018-09-29 2019-09-26 Positive-electrode plate, lithium-ion battery equipped with the positive-electrode plate, battery module, battery pack, and apparatus

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN201811151916.1A CN110970613B (zh) 2018-09-29 2018-09-29 一种正极极片以及使用该正极极片的锂离子电池
CN201811151916.1 2018-09-29

Publications (1)

Publication Number Publication Date
WO2020063740A1 true WO2020063740A1 (zh) 2020-04-02

Family

ID=69950995

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2019/108134 Ceased WO2020063740A1 (zh) 2018-09-29 2019-09-26 一种正极极片、使用该正极极片的锂离子电池、电池模块、电池包及装置

Country Status (4)

Country Link
US (1) US12074315B2 (zh)
EP (1) EP3787068B1 (zh)
CN (1) CN110970613B (zh)
WO (1) WO2020063740A1 (zh)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114477300A (zh) * 2022-01-26 2022-05-13 蜂巢能源科技股份有限公司 一种钠离子电池正极材料及其制备方法和应用

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112467121A (zh) * 2020-12-03 2021-03-09 珠海冠宇电池股份有限公司 一种正极片及其制备方法和应用
CN115188957A (zh) * 2021-04-12 2022-10-14 深圳市德方创域新能源科技有限公司 补锂添加剂及其制备方法与应用
WO2022267013A1 (zh) * 2021-06-25 2022-12-29 宁德新能源科技有限公司 电化学装置及电子装置
CN113793930B (zh) * 2021-09-17 2023-04-25 珠海冠宇电池股份有限公司 一种正极片及锂离子电池
CN115979907B (zh) * 2021-10-14 2024-11-19 比亚迪股份有限公司 一种电极片的孔隙检测方法及电极片
CN114583104B (zh) * 2022-02-24 2023-11-28 珠海冠宇动力电池有限公司 一种正极片和电池
CN114864886B (zh) * 2022-04-02 2024-02-27 万华化学集团股份有限公司 一种正极材料及其制备方法
CN115799441B (zh) * 2023-02-10 2023-07-14 欣旺达电动汽车电池有限公司 一种锂离子电池及用电装置
CN118738261A (zh) * 2023-03-28 2024-10-01 宁德时代新能源科技股份有限公司 正极极片及其制备方法、电极组件、电池单体、电池和用电装置
CN117497766A (zh) * 2024-01-03 2024-02-02 宁德时代新能源科技股份有限公司 负极极片及其制备方法、电池和用电装置

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101911368A (zh) * 2007-12-26 2010-12-08 松下电器产业株式会社 非水电解质二次电池
US20120077082A1 (en) * 2010-06-14 2012-03-29 Lee Se-Hee Lithium Battery Electrodes with Ultra-thin Alumina Coatings
CN105977449A (zh) * 2015-03-12 2016-09-28 丰田自动车株式会社 固体电池用正极活性物质的制造方法
CN109950470A (zh) * 2017-12-20 2019-06-28 宁德时代新能源科技股份有限公司 一种负极极片，其制备方法及电化学装置

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5374851B2 (ja) * 2007-10-15 2013-12-25 ソニー株式会社 リチウムイオン二次電池用負極およびリチウムイオン二次電池
JP5271275B2 (ja) * 2007-12-14 2013-08-21 パナソニック株式会社 非水電解質二次電池の製造方法
US8980472B2 (en) 2010-08-05 2015-03-17 Toyota Jidosha Kabushiki Kaisha Secondary battery
CN102420300A (zh) * 2011-12-07 2012-04-18 保定市山河日月实业有限公司 一种锂离子电池隔膜的制备方法
CN103682247B (zh) * 2012-09-24 2017-02-08 华为技术有限公司 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
CN103413966B (zh) * 2013-07-18 2015-08-05 中国科学院金属研究所 一种具有膜电极结构的锂离子电池及其制备方法
CN104064705B (zh) * 2014-06-09 2017-01-04 东莞市魔方新能源科技有限公司 一种锂离子二次电池用复合隔膜、其制造方法及含该隔膜的电化学装置
KR102072220B1 (ko) * 2016-01-12 2020-01-31 주식회사 엘지화학 디바이스에 대한 탑재 공간이 최소화된 전지팩
CN106229447A (zh) * 2016-08-10 2016-12-14 东莞永蓝电子科技有限公司 一种锂离子电池
CN107749457B (zh) * 2016-11-18 2020-07-31 万向一二三股份公司 一种含正极陶瓷涂层的锂离子电池
CN109994705B (zh) 2017-12-29 2022-01-14 宁德时代新能源科技股份有限公司 一种正极极片，其制备方法及电化学装置
CN108807974B (zh) * 2018-06-29 2021-07-09 宁德时代新能源科技股份有限公司 锂离子电池

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101911368A (zh) * 2007-12-26 2010-12-08 松下电器产业株式会社 非水电解质二次电池
US20120077082A1 (en) * 2010-06-14 2012-03-29 Lee Se-Hee Lithium Battery Electrodes with Ultra-thin Alumina Coatings
CN105977449A (zh) * 2015-03-12 2016-09-28 丰田自动车株式会社 固体电池用正极活性物质的制造方法
CN109950470A (zh) * 2017-12-20 2019-06-28 宁德时代新能源科技股份有限公司 一种负极极片，其制备方法及电化学装置

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP3787068A4

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114477300A (zh) * 2022-01-26 2022-05-13 蜂巢能源科技股份有限公司 一种钠离子电池正极材料及其制备方法和应用
CN114477300B (zh) * 2022-01-26 2023-12-22 蜂巢能源科技股份有限公司 一种钠离子电池正极材料及其制备方法和应用

Also Published As

Publication number Publication date
CN110970613A (zh) 2020-04-07
EP3787068B1 (en) 2022-10-19
US12074315B2 (en) 2024-08-27
EP3787068A4 (en) 2021-08-11
CN110970613B (zh) 2021-06-15
EP3787068A1 (en) 2021-03-03
US20210210749A1 (en) 2021-07-08

Similar Documents

Publication Publication Date Title
CN115917825B (zh) 二次电池与含有该二次电池的电池模块、电池包和用电装置
WO2020063740A1 (zh) 一种正极极片、使用该正极极片的锂离子电池、电池模块、电池包及装置
CN113659111B (zh) 负极极片、电芯、锂离子电池、电子产品及电动车辆
CN103560225B (zh) 非水二次电池
CN103959547B (zh) 锂二次电池
CN102088109B (zh) 非水电解质二次电池和隔膜
CN104170120B (zh) 锂二次电池组、以及使用了其的电子设备、充电系统和充电方法
CN108199035A (zh) 锂二次电池
CN103038928A (zh) 锂二次电池
CN105576279A (zh) 锂二次电池
CN110265622B (zh) 正极极片及锂离子二次电池
WO2020238628A1 (zh) 负极极片、电芯、锂离子电池及其制备方法和包含锂离子电池的装置
CN111512480A (zh) 锂二次电池
WO2023070268A1 (zh) 一种电化学装置及包含该电化学装置的用电装置
WO2025015923A1 (zh) 锂二次电池和用电装置
WO2020043151A1 (zh) 正极极片、其制备方法及锂离子二次电池
WO2024230127A1 (zh) 电解液、锂二次电池及用电装置
CN117121257A (zh) 锂二次电池用非水性电解质溶液及包含其的锂二次电池
WO2024217031A1 (zh) 一种二次电池和用电设备
WO2025200884A1 (zh) 二次电池及用电装置
WO2025123962A1 (zh) 二次电池及装置
WO2023070992A1 (zh) 电化学装置及包括其的电子装置
CN115336068A (zh) 电化学装置及包括其的电子装置
JP7715845B2 (ja) 電気化学装置及び当該電気化学装置を含む電子装置
CN105009349B (zh) 锂二次电池

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 19866720

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2019866720

Country of ref document: EP

Effective date: 20201125

NENP Non-entry into the national phase

Ref country code: DE