WO2020063371A1 - 正极极片及锂离子二次电池 - Google Patents

正极极片及锂离子二次电池 Download PDF

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WO2020063371A1
WO2020063371A1 PCT/CN2019/105727 CN2019105727W WO2020063371A1 WO 2020063371 A1 WO2020063371 A1 WO 2020063371A1 CN 2019105727 W CN2019105727 W CN 2019105727W WO 2020063371 A1 WO2020063371 A1 WO 2020063371A1
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Prior art keywords
positive electrode
active material
electrode active
electrode sheet
ion secondary
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PCT/CN2019/105727
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English (en)
French (fr)
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钟韡
姜玲燕
葛销明
梁涛
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宁德时代新能源科技股份有限公司
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Priority to EP19866164.7A priority Critical patent/EP3680965B1/en
Priority to US16/767,893 priority patent/US11196041B2/en
Publication of WO2020063371A1 publication Critical patent/WO2020063371A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • 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
    • H01M4/36—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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • 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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/136—Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
    • 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
    • H01M4/48—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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
    • 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
    • H01M2004/028—Positive electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present application belongs to the technical field of secondary batteries, and particularly relates to a positive electrode sheet and a lithium ion secondary battery.
  • Lithium-ion secondary batteries can provide stable voltage and current, have a high-voltage platform, high specific energy, and a wide temperature range, and are environment-friendly and easy to carry. They have become the mainstream power of various consumer electronics and electric products. source. In recent years, there have been increasing demands on the safety performance and cycle performance of lithium-ion secondary batteries.
  • the inventors have discovered that the safety performance of lithium ion secondary batteries can be improved by formulating a mixed system positive electrode active material with a nickel-containing ternary positive electrode material and lithium manganate in the spinel phase.
  • the addition of spinel phase lithium manganate will cause the ion transmission performance of the positive electrode sheet to decrease, which makes the low-temperature kinetics performance, high-temperature cycling performance, and high-temperature storage performance of lithium ion secondary batteries using the mixed system positive active material. Low, unable to meet market requirements.
  • the present inventors have conducted a lot of research to improve the ion transmission performance of the positive electrode sheet using a nickel-containing ternary positive electrode material and a spinel phase lithium manganate mixed positive electrode active material, so as to obtain both high safety performance, Lithium-ion secondary battery with low-temperature kinetics performance, high-temperature cycling performance, and high-temperature storage performance.
  • a first aspect of 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 first positive electrode active material represented by chemical formula (1).
  • Me and M are each independently Co, Mn, One or more of Fe, Cr, Ti, Zn, V, Al, Zr, and Ce, and Me is not the same as M, and A is one or more of S, N, F, Cl, Br, and I ,
  • Z is one of Ni, Fe, Cr, Ti, Zn, V, Al, Mg, Zr, and Ce.
  • B is one or more of S, N, F, Cl, Br, and I;
  • the positive electrode piece satisfies formula (1)
  • R is the resistance of the positive pole piece in ⁇ ;
  • P is the compacted density of the positive pole piece in g / cm 3 ;
  • C is the single-sided areal density of the positive pole piece in g / 1540.25mm 2 .
  • a second aspect of the present application provides a lithium ion secondary battery including a positive electrode sheet, a negative electrode sheet, a separator, and an electrolyte, wherein the positive electrode sheet is the positive electrode sheet according to the first aspect of the embodiments of the present application.
  • the Lithium-ion secondary batteries simultaneously take into account higher safety performance, low-temperature kinetics performance, high-temperature cycling performance, and high-temperature storage performance.
  • any lower limit may be combined with any upper limit to form an unclearly stated range; and any lower limit may be combined with other lower limits to form an unclearly stated range, and likewise any arbitrary upper limit may be combined with any other upper limit to form an unclearly stated range.
  • every point or single value between the endpoints of the range is included in the range. Therefore, each point or single numerical value can be used as its own lower limit or upper limit in combination with any other point or single numerical value or in combination with other lower limits or upper limits to form an unclearly recorded range.
  • An embodiment of the present application provides a positive electrode sheet, which includes 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 current collector has two surfaces facing in the thickness direction of the positive electrode current collector, and the positive electrode active material layer is laminated on one or both of the two surfaces of the positive electrode current collector.
  • the positive electrode active material layer contains a positive electrode active material, and can perform reversible deintercalation / intercalation of lithium ions during operation.
  • the positive current collector collects and outputs the generated current.
  • the positive electrode active material includes a first positive electrode active material and a second positive electrode active material.
  • the first positive active material is a compound represented by the chemical formula (1):
  • Me and M are each independently Co, Mn, One or more of Fe, Cr, Ti, Zn, V, Al, Zr, and Ce, and Me is not the same as M, and A is one or more of S, N, F, Cl, Br, and I .
  • 0.5 ⁇ a ⁇ 1, Me and M are each independently one or more of Co, Mn, and Al.
  • the second positive active material is a compound represented by the chemical formula (2):
  • Z is one of Ni, Fe, Cr, Ti, Zn, V, Al, Mg, Zr, and Ce.
  • B is one or more of S, N, F, Cl, Br, and I.
  • r R ⁇ P / C and 0.04 ⁇ R ⁇ P / C ⁇ 10.
  • R is the resistance of the positive electrode piece, in ⁇ ;
  • P is the compacted density of the positive electrode piece, in g / cm 3 ;
  • C is the single-surface area density of the positive electrode piece, in g / 1540.25 mm 2 .
  • 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 volume v of the positive electrode active material layer may be the product of the area A r of the positive electrode active material layer and the thickness of the positive electrode active material layer.
  • the positive electrode sheet of the embodiment of the present application can fully exert the synergistic effect between the first positive electrode active material and the second positive electrode active material, so that the positive electrode active material has high structural stability, and the side reaction of the electrolyte on the surface of the positive electrode active material Significantly reduce, effectively suppress gas production and reduce heat production.
  • the positive electrode sheet also has high electron and ion transmission performance.
  • the positive electrode sheet of the embodiment of the present application can effectively improve the safety performance, low-temperature kinetics performance, and high-temperature cycle performance of the lithium-ion secondary battery on the premise that the lithium-ion secondary battery has a high specific capacity and energy density. And high temperature storage performance.
  • the synergistic effect between the first positive electrode active material and the second positive electrode active material can also effectively inhibit the polarization of the first positive electrode active material from increasing during the cycle, and reduce the first The ginger-Taylor effect of the two positive active materials, thereby reducing the positive polarization. Therefore, the positive electrode capacity loss is significantly reduced, thereby further improving the cycle performance of the lithium ion secondary battery.
  • the positive electrode sheet of the embodiment of the present application has higher electron and ion transmission performance, and also makes the lithium ion secondary battery have higher rate performance and lower low-temperature DC internal resistance, thereby further improving the low temperature of the lithium ion secondary battery. Dynamic performance.
  • the lithium ion secondary battery can simultaneously achieve high safety performance, low temperature dynamic performance, high temperature cycle performance, and high temperature storage performance.
  • the resistance, compacted density, and single-sided areal density of the positive electrode pieces are all key technical parameters in the design and manufacture of lithium ion secondary batteries.
  • the resistance of the positive electrode sheet is increased, and the rate performance and cycle performance of the lithium ion secondary battery are reduced. If the compacted density of the positive electrode sheet is too large or too small, the rate performance and cycle performance of the battery will be deteriorated. If the single-sided area density of the positive electrode sheet is too large, the cycle life of the battery will be reduced, and the rate performance of the battery will be affected, especially the discharge capacity of the battery will be reduced at a high rate. With the same battery capacity, the length of the current collector and the separator increases, increasing the ohmic internal resistance of the battery.
  • the technical parameter r proposed in this application mainly reflects the characteristics of the positive electrode sheet itself, and is used to monitor and judge the design and fabrication of the positive electrode sheet, which can ensure that the positive electrode sheet reaches the expected design value, so that the lithium ion secondary battery The electrochemical performance achieved the desired effect.
  • the technical parameter r of the positive electrode piece satisfies: 0.5 ⁇ r ⁇ 8.
  • the resistance R of the positive electrode sheet is preferably R ⁇ 5 ⁇ , and more preferably R ⁇ 1 ⁇ . This is beneficial to improve the rate performance and cycle performance of the lithium ion secondary battery.
  • the compacted density P of the positive electrode sheet is preferably 2.6 g / cm 3 ⁇ P ⁇ 3.5 g / cm 3 . This facilitates the migration of electrons and ions in the positive electrode sheet, thereby improving the rate performance and cycle performance of the lithium ion secondary battery.
  • the single-sided areal density C of the positive electrode sheet is preferably 0.25 g / 1540.25 mm 2 ⁇ C ⁇ 0.40 g / 1540.25 mm 2 . This can improve the rate performance and cycle performance of the lithium ion secondary battery while ensuring the charge and discharge capacity.
  • the thickness of the positive electrode active material layer is preferably 116 ⁇ m to 185 ⁇ m, and more preferably 116 ⁇ m to 149 ⁇ m. This is beneficial to the cathode electrode to obtain a lower resistance, and to ensure that the battery has a higher charge and discharge capacity.
  • the weight ratio of the first positive electrode active material and the second positive electrode active material is preferably 0.05: 1 to 19: 1, more preferably 0.4: 1 to 19: 1, and still more preferably 1: 1 to 4: 1.
  • the positive electrode active material has higher structural stability, and further reduces side reactions of the electrolyte on the surface of the positive electrode active material.
  • the positive electrode active material can also reduce the dissolution of manganese, on the one hand, it reduces the loss of positive electrode capacity and the increase of the positive electrode resistance caused by the structural destruction of the positive electrode active material; Large and negative lithium precipitation. Therefore, the positive electrode sheet using the positive electrode active material can better improve the safety performance, low temperature dynamic performance, high temperature cycle performance, and high temperature storage performance of the lithium ion secondary battery.
  • the weight percentage content of the second positive electrode active material in the positive electrode active material layer is preferably 4 wt% to 95 wt%, and more preferably 4 wt% to 67 wt%.
  • the average particle diameter D v 50 of the first positive electrode active material is preferably 4 ⁇ m to 18 ⁇ m and the average particle diameter D v 90 is preferably 10 ⁇ m to 24 ⁇ m. More preferably, the average particle diameter D v 50 of the first positive electrode active material is 8 ⁇ m to 16 ⁇ m and the average particle diameter D v 90 is 10 ⁇ m to 20 ⁇ m.
  • the average particle diameter D v 50 of the second positive electrode active material is preferably 8 ⁇ m to 20 ⁇ m and the average particle diameter D v 90 is preferably 14 ⁇ m to 35 ⁇ m. More preferably, the average particle diameter D v 50 of the second positive electrode active material is 11 ⁇ m to 16 ⁇ m and the average particle diameter D v 90 is 18 ⁇ m to 30 ⁇ m.
  • the use of the first positive electrode active material and the second positive electrode active material having the above-mentioned particle size distribution can further improve the electron and ion transmission performance of the positive electrode sheet, thereby further improving the low-temperature kinetic performance and high-temperature cycling performance of the lithium ion secondary battery.
  • BET first cathode active material is preferably a specific surface area of 0.4m 2 / g ⁇ 1m 2 / g, more preferably 0.5m 2 /g ⁇ 0.6m 2 / g.
  • the second positive electrode active material BET specific surface area is preferably 0.4m 2 /g ⁇ 0.7m 2 / g, more preferably 0.5m 2 /g ⁇ 0.7m 2 / g.
  • the positive electrode active material layer may further include a conductive agent and / or a binder.
  • the application does not specifically limit the types of the conductive agent and the binder, and may be selected according to actual needs.
  • the conductive agent of the positive electrode active material layer may be one or more of graphite, superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers;
  • the binder of the material layer may be styrene-butadiene rubber (SBR), water-based acrylic resin, carboxymethyl cellulose (CMC), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE) ), One or more of polyvinyl butyral (PVB), ethylene-vinyl acetate copolymer (EVA), and polyvinyl alcohol (PVA).
  • the mass ratio of the conductive agent to the positive electrode active material is greater than or equal to 1.5: 95.5. This is beneficial to obtain a lower positive electrode sheet resistance.
  • the weight percentage of the binder in the positive electrode active material layer is less than or equal to 2 wt%. This is beneficial to obtain a lower positive electrode sheet resistance.
  • the positive electrode current collector may be a metal foil or a porous metal plate, for example, a foil or a porous plate using a metal such as aluminum, copper, nickel, titanium, or silver, or an alloy thereof, such as aluminum foil.
  • the thickness of the positive electrode current collector is preferably 5 ⁇ m to 20 ⁇ m, more preferably 6 ⁇ m to 18 ⁇ m, and still more preferably 8 ⁇ m to 16 ⁇ m.
  • the positive electrode sheet of the present application can be prepared by a coating method.
  • the positive electrode slurry is first coated on at least one surface of the positive electrode current collector to obtain a positive electrode active material coating layer, and then, after drying, cold pressing, and the like, the positive electrode active material layer is obtained on the positive electrode current collector to obtain a positive electrode. sheet.
  • a method for preparing a positive electrode sheet includes the following steps:
  • the solvent may be N-methylpyrrolidone (NMP), and the mixture is stirred to a uniform system to obtain a positive electrode slurry.
  • NMP N-methylpyrrolidone
  • the positive electrode active material includes the first positive electrode active material and the second positive electrode active material described above.
  • the first positive electrode active material and the second positive electrode active material may be added at the same time, or they may be added in order; the first positive electrode active material and the second positive electrode active material may be added independently at one time, of course. Each was added separately in batches.
  • the first positive electrode active material is first mixed with a binder, a conductive agent, and an organic solvent to make a stable pre-slurry; and then a second positive electrode active material is added to the pre-slurry.
  • the mixture was stirred and mixed to prepare a positive electrode slurry.
  • the particles in the positive electrode active material layer can be uniformly distributed, and the conductive agent can be prevented from agglomerating, thereby forming a uniformly distributed conductive network. Therefore, the resistance of the positive electrode piece is greatly reduced, and the dynamic performance and cycle performance of the battery can be improved.
  • step S100 other additives such as lithium carbonate Li 2 CO 3 may be added. Adding lithium carbonate can further improve the battery's overcharge performance.
  • the added amount can satisfy that the weight percentage of lithium carbonate in the positive electrode active material layer is 1 wt% to 5 wt%, such as 1 wt% to 1.5 wt%.
  • step S100 the method and apparatus known in the art can be used to stir the mixture.
  • the materials are added to a vacuum mixer for stirring and mixing, and the vacuum pressure is -20KPa or less (gauge pressure).
  • the common rotation rate is 20RPM-30RPM and the self-rotation rate is 1100RPM-1300RPM.
  • the common rotation rate is 25RPM and the self-rotation rate is 1200RPM.
  • the whole stirring process time is 4h-7h. Among them, RPM (Revolutions Per Minute) is the number of revolutions per minute.
  • the viscosity of the positive electrode slurry is preferably 5000 mPa ⁇ s or more, for example, 5000 mPa ⁇ s to 7000 mPa ⁇ s, and for example, 5000 mPa ⁇ s to 6000 mPa ⁇ s.
  • the density of the positive electrode slurry is preferably greater than 1.25 kg / L. This is beneficial to make the slurry more uniform and the conductive agent is not easy to agglomerate, which is conducive to making the battery have higher rate performance and cycle performance.
  • the positive electrode slurry is uniformly coated on the positive electrode current collector to obtain an initial positive electrode sheet.
  • the initial positive electrode sheet is dried, cold-pressed and other processes to obtain a positive electrode sheet.
  • the initial positive electrode sheet may be transferred to an oven for drying, and the drying temperature is 120 ° C to 140 ° C, such as 130 ° C.
  • the cold pressing process can be performed using methods and devices known in the art, and those skilled in the art can select according to the requirement of the compaction density P of the positive electrode sheet.
  • the positive electrode sheet of the embodiment of the present application can be realized by the above preparation method.
  • An embodiment of the present application further provides a lithium ion secondary battery, which includes a positive electrode sheet, a negative electrode sheet, a separator, and an electrolyte.
  • the positive electrode piece adopts any one of the positive electrode pieces provided in the embodiments of the present application.
  • the negative electrode sheet may be a metallic lithium sheet, or may include a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector.
  • the negative active material layer usually contains a negative active material and optional conductive agent, binder, and thickener.
  • the negative electrode active material may be natural graphite, artificial graphite, mesophase micro carbon sphere (MCMB), hard carbon, soft carbon, silicon, silicon-carbon composite, SiO, Li-Sn alloy, Li-Sn-O alloy , Sn, SnO, SnO 2 , one or more of lithium titanate Li 4 Ti 5 O 12 , Li-Al alloy and metallic lithium with a spinel structure;
  • the conductive agent of the negative electrode active material layer may be graphite, super One or more of carbon guide, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers;
  • the binder of the negative electrode active material layer may be styrene-butadiene rubber (SBR) , Polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyvinyl
  • the negative electrode current collector can be made of a metal foil or a porous metal plate, for example, a foil or a porous plate using a metal such as copper, nickel, titanium, or iron, or an alloy thereof, such as copper foil.
  • the negative electrode sheet can be prepared according to a conventional method in the art.
  • the negative electrode active material and optional conductive agent, binder and thickener are usually dispersed in a solvent.
  • the solvent can be N-methylpyrrolidone (NMP) or deionized water to form a uniform negative electrode slurry.
  • NMP N-methylpyrrolidone
  • the material is coated on the negative electrode current collector, and the negative electrode pieces are obtained through drying, cold pressing and other processes.
  • the separator is not particularly limited, and any well-known porous structure separator having electrochemical stability and chemical stability can be selected.
  • the separator is a single-layer or multilayer film selected from one or more of glass fiber, non-woven fabric, polyethylene (PE), polypropylene (PP), and polyvinylidene fluoride (PVDF).
  • the electrolytic solution includes an organic solvent and an electrolyte lithium salt.
  • the application does not specifically limit the types of organic solvents and electrolyte lithium salts, and can be selected according to actual needs.
  • the organic solvent may be selected from ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), carbonic acid Dipropyl ester (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), butylene carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), One or more of ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), and diethyl sul
  • the electrolyte lithium salt may be selected from LiPF 6 (lithium hexafluorophosphate), LiBF 4 (lithium tetrafluoroborate), LiClO 4 (lithium perchlorate), LiAsF 6 (lithium hexafluoroarsenate), LiFSI (lithium bisfluorosulfonimide) , LiTFSI (lithium bistrifluoromethanesulfonimide), LiTFS (lithium triflate), LiDFOB (lithium difluorooxalate borate), LiBOB (lithium dioxalate borate), LiPO 2 F 2 (lithium difluorophosphate) ), One or more of LiDFOP (lithium difluorobisoxalate phosphate) and LiTFOP (lithium tetrafluorooxalate phosphate).
  • LiPF 6 lithium hexafluorophosphate
  • LiBF 4 lithium tetrafluoroborate
  • LiClO 4 lithium per
  • the electrolyte may optionally include an additive, which may be any additive that can be used as a lithium ion secondary battery, which is not specifically limited in this application, and may be selected according to actual needs.
  • the additive may be selected from vinylene carbonate (VC), ethylene ethylene carbonate (VEC), fluoroethylene carbonate (FEC), succinonitrile (SN), adiponitrile (ADN), 1, One of 3-propene sultone (PST), sulfonate cyclic quaternary ammonium salt, tris (trimethylsilane) phosphate (TMSP), and tris (trimethylsilane) borate (TMSB) Or more.
  • VEC vinylene carbonate
  • VEC ethylene ethylene carbonate
  • FEC fluoroethylene carbonate
  • SN succinonitrile
  • ADN adiponitrile
  • PST sulfonate cyclic quaternary ammonium salt
  • tris trimethylsilane) phosphate
  • the electrolytic solution can be prepared according to a method conventional in the art.
  • the organic solvent, the lithium salt of the electrolyte and optional additives can be mixed uniformly to obtain an electrolytic solution.
  • the order in which the materials are added is not particularly limited.
  • the electrolyte lithium salt and optional additives are added to an organic solvent and mixed uniformly to obtain an electrolytic solution.
  • the electrolyte lithium salt can be added to the organic solvent first, and then optional additives can be added to the organic solvent separately or simultaneously.
  • the positive electrode sheet, the separator film and the negative electrode sheet are stacked in order, so that the isolation film is located between the positive electrode sheet and the negative electrode sheet to play a role of isolation, to obtain a battery core, or to obtain a battery core after winding;
  • the battery is placed in a packaging case, the electrolyte is injected and sealed to obtain a lithium ion secondary battery.
  • the lithium ion secondary battery of the present application simultaneously takes into consideration higher safety performance, low temperature dynamic performance, high temperature cycle performance, and high temperature storage performance.
  • the first positive electrode active material LiNi 0.5 Co 0.2 Mn 0.3 O 2 the second positive electrode active material LiMn 2 O 4 , binder PVDF, conductive carbon black, carbon nanotube (CNT) conductive paste, and Li 2 CO 3 , Where the weight ratio of LiNi 0.5 Co 0.2 Mn 0.3 O 2 , LiMn 2 O 4 , PVDF, conductive carbon black, CNT and Li 2 CO 3 is 90.25: 4.75: 1.1: 2.3: 0.4: 1.2, add solvent NMP, Stir to a uniform and transparent system under stirring to obtain a positive electrode slurry. The viscosity of the positive electrode slurry is 5100 mPa ⁇ s and the stirring time is 4 h.
  • the drying temperature is 130 ° C, and then cold pressing and cutting are performed to obtain a positive electrode sheet.
  • the weight percentage content of the first positive electrode active material LiNi 0.5 Co 0.2 Mn 0.3 O 2 in the positive electrode active material layer was 90.25 wt%, and the weight percentage content of the second positive electrode active material LiMn 2 O 4 in the positive electrode active material layer was 4.75 wt. %.
  • the negative electrode active material artificial graphite, the thickener sodium carboxymethyl cellulose (CMC), and the styrene-butadiene rubber (SBR) binder are mixed according to a mass ratio of 98: 1: 1, and the solvent is added with deionized water to function in a vacuum mixer.
  • a negative electrode slurry is obtained below; the negative electrode slurry is uniformly coated on the negative electrode current collector copper foil; then transferred to an oven to dry at a drying temperature of 120 ° C., and then cold-pressed and cut to obtain a negative electrode sheet.
  • Ethylene carbonate (EC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC) were mixed uniformly in a volume ratio of 1: 1: 1 to obtain an organic solvent.
  • 1 mol / L LiPF 6 was dissolved in the organic solvent and mixed uniformly to obtain an electrolytic solution.
  • the positive electrode sheet, the separator film, and the negative electrode sheet are stacked in this order.
  • the separator film uses a 14 ⁇ m thick polypropylene (PP) film (model A273, provided by Celgard), which is located between the positive electrode sheet and the negative electrode sheet. It plays a role of isolation, and then is wound into a square bare cell, and the electrode tabs are welded. The bare cell is inserted into the shell, the electrolyte is injected and sealed, and then it is subjected to the processes of standing, forming, and shaping to obtain lithium ion secondary. battery.
  • PP polypropylene
  • Example 1 Different from Example 1, the relevant parameters in the preparation steps of the positive electrode sheet are adjusted, as shown in Table 1.
  • Example 1 The difference from Example 1 is that the positive electrode active material in the positive electrode sheet contains only LiMn 2 O 4 .
  • the positive electrode active material in the positive electrode sheet contains only LiNi 0.8 Co 0.1 Mn 0.1 O 2 .
  • the weight percentages of the positive electrode active material, conductive carbon black, and CNT in the positive electrode active material layer of the positive electrode sheet were 90% by weight, 5.7% by weight, and 2% by weight, respectively.
  • the viscosity of the positive electrode slurry was 4000 mPa ⁇ s, and the stirring time was 6 h.
  • the viscosity of the positive electrode slurry was 4300 mPa ⁇ s, and the stirring time was 5.5 h.
  • Use the BT3562 internal resistance tester to test the resistance of the positive pole piece including: clamping the positive pole piece between the two conductive terminals of the internal resistance tester and applying pressure to fix the resistance R of the positive pole piece, where The diameter of the conductive terminal is 14 mm, the applied pressure is 15 MPa to 27 MPa, and the mining point time is in the range of 5 s to 17 s.
  • Lithium ion secondary battery 3C rate discharge capacity retention rate (%) 3C rate discharge capacity / 1C rate discharge capacity ⁇ 100%.
  • Capacity retention rate (%) of lithium ion secondary battery after high temperature storage for 60 days discharge capacity after high temperature storage for 60 days / initial discharge capacity ⁇ 100%.
  • the weight percentage content of the first positive electrode active material and the weight percentage content of the second positive electrode active material are both weight percentage contents in the positive electrode active material layer.
  • Example 1 0.50 95 789 91.0 652.0
  • Example 2 1.04 95 664 90.0 659.0
  • Example 3 9.92 92 456 88.0 666.0
  • Example 4 4.48 92 420 88.0 675.0
  • Example 5 0.04 94 280 86.2 686.7
  • Example 6 4.83 95 310 87.2 706.1
  • Example 7 7.14 94 300 86.5 690.0
  • Example 8 5.72 93 230 87.0 346.0
  • Example 9 4.72 90 446 88.8 327.5 Comparative Example 1 19.88 85 130 76.9 732.1 Comparative Example 2 22.22 87 150 77.6 370.0 Comparative Example 3 0.03 87 240 83.0 720.0
  • Comparative Example 4 18.00 85 200 85.0 730.0 Comparative Example 5 25.78 88 90 80.0 358.0
  • the positive electrode active material of the positive electrode sheet is a mixed system of the first positive electrode active material and the second positive electrode active material, and the positive electrode sheet satisfies 0.04 ⁇ R ⁇ P / C ⁇ 10, While improving the safety performance of the lithium-ion secondary battery, the low-temperature kinetics performance, high-temperature storage performance, and high-temperature cycling performance of the lithium-ion secondary battery are also improved.
  • R ⁇ P / C ⁇ 0.04 and when R ⁇ P / C> 10
  • the lithium ion secondary battery has low rate performance and high low-temperature DCR, which affects the low-temperature dynamic performance of the battery and the high temperature of the battery. Storage performance and high-temperature cycling performance have also deteriorated significantly.

Abstract

一种正极极片及锂离子二次电池，包括正极集流体以及设置于所述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括第一正极活性物质Li 1+xNi aMe bM 1-a-bO 2-yA y和第二正极活性物质Li 1+zMn cZ 2-cO 4-dB d，其中，所述正极极片满足0.04≤R·P/C≤10，R为所述正极极片的电阻，单位为Ω；P为所述正极极片的压实密度，单位为g/cm 3；C为所述正极极片的单面面密度，单位为g/1540.25mm 2。所述锂离子二次电池能够同时兼顾较高的安全性能、低温动力学性能、高温循环性能及高温存储性能。

Description

正极极片及锂离子二次电池
相关申请的交叉引用
本申请要求享有于2018年09月28日提交的名称为“正极极片及锂离子二次电池”的中国专利申请201811136888.6的优先权，该申请的全部内容通过引用并入本文中。
技术领域
本申请属于二次电池技术领域，具体涉及一种正极极片及锂离子二次电池。
背景技术
锂离子二次电池能够提供稳定的电压和电流，具有高电压平台、高比能量及宽广的温度使用范围，并且环境友好、携带方便，已成为当前各类消费类电子产品及电动产品的主流动力源。近年来，人们对锂离子二次电池的安全性能及循环性能提出了越来越高的要求。
发明内容
本发明人发现，通过将含镍三元正极材料与尖晶石相的锰酸锂配成混合体系正极活性物质，可以提高锂离子二次电池的安全性能。但是，尖晶石相锰酸锂的加入会引起正极极片的离子传输性能降低，使得采用该混合体系正极活性物质的锂离子二次电池的低温动力学性能、高温循环性能及高温存储性能较低，无法满足市场要求。
本发明人进行了大量研究，旨在改善采用含镍三元正极材料和尖晶石相锰酸锂混合体系正极活性物质的正极极片的离子传输性能，从而获得同时兼顾较高的安全性能、低温动力学性能、高温循环性能及高温存储性能的锂离子二次电池。
本申请第一方面提供一种正极极片，包括正极集流体以及设置于正极集流体的至少一个表面上的正极活性物质层，正极活性物质层包含化学式(1)所示的第一正极活性物质和化学式(2)所示的第二正极活性物质，
Li 1+xNi aMe bM 1-a-bO 2-yA y     化学式(1)
化学式(1)中，-0.1≤x≤0.2，0<a<1，0<b<1，0<a+b<1，0≤y<0.2，Me和M各自独立地为Co、Mn、Fe、Cr、Ti、Zn、V、Al、Zr及Ce中的一种或多种、且Me与M不相同，A为S、N、F、Cl、Br及I中的一种或多种，
Li 1+zMn cZ 2-cO 4-dB d     化学式(2)
化学式(2)中，-0.1≤z≤0.2，0<c≤2，0≤d<1，Z为Ni、Fe、Cr、Ti、Zn、V、Al、Mg、Zr及Ce中的一种或多种，B为S、N、F、Cl、Br及I中的一种或多种；
其中，正极极片满足式(1)，
0.04≤R·P/C≤10     式(1)
式(1)中，R为正极极片的电阻，单位为Ω；P为正极极片的压实密度，单位为g/cm 3；C为正极极片的单面面密度，单位为g/1540.25mm 2。
本申请第二方面提供一种锂离子二次电池，包括正极极片、负极极片、隔离膜和电解液，其中正极极片为根据本申请实施例第一方面的正极极片。
本申请提供的正极极片及锂离子二次电池中，由于正极活性物质层包括第一正极活性物质和第二正极活性物质，并且正极极片满足0.04≤R·P/C≤10，能使锂离子二次电池同时兼顾较高的安全性能、低温动力学性能、高温循环性能及高温存储性能。
具体实施方式
为了使本申请的发明目的、技术方案和有益技术效果更加清晰，以下结合实施例对本申请进行进一步详细说明。应当理解的是，本说明书中描述的实施例仅仅是为了解释本申请，并非为了限定本申请。
为了简便，本文仅明确地公开了一些数值范围。然而，任意下限可以 与任何上限组合形成未明确记载的范围；以及任意下限可以与其它下限组合形成未明确记载的范围，同样任意上限可以与任意其它上限组合形成未明确记载的范围。此外，尽管未明确记载，但是范围端点间的每个点或单个数值都包含在该范围内。因而，每个点或单个数值可以作为自身的下限或上限与任意其它点或单个数值组合或与其它下限或上限组合形成未明确记载的范围。
在本文的描述中，需要说明的是，除非另有说明，“以上”、“以下”为包含本数，“一种或多种”中“多种”的含义是两个以上。
本申请的上述发明内容并不意欲描述本申请中的每个公开的实施方式或每种实现方式。如下描述更具体地举例说明示例性实施方式。在整篇申请中的多处，通过一系列实施例提供了指导，这些实施例可以以各种组合形式使用。在各个实例中，列举仅作为代表性组，不应解释为穷举。
正极极片
本申请实施例提供一种正极极片，该正极极片包括正极集流体以及设置于正极集流体至少一个表面上的正极活性物质层。作为一个示例，正极集流体具有在自身厚度方向上相对的两个表面，正极活性物质层层合设置于正极集流体的两个表面中的任意一者或两者上。正极活性物质层包含正极活性物质，在工作过程中能够进行锂离子的可逆脱嵌/入嵌。正极集流体将产生的电流汇集并输出。
正极活性物质包括第一正极活性物质和第二正极活性物质。
第一正极活性物质为化学式(1)所示的化合物：
Li 1+xNi aMe bM 1-a-bO 2-yA y     化学式(1)
化学式(1)中，-0.1≤x≤0.2，0<a<1，0<b<1，0<a+b<1，0≤y<0.2，Me和M各自独立地为Co、Mn、Fe、Cr、Ti、Zn、V、Al、Zr及Ce中的一种或多种、且Me与M不相同，A为S、N、F、Cl、Br及I中的一种或多种。
可选地，化学式(1)中，0.5≤a<1，Me和M各自独立地为Co、Mn及Al中的一种或多种。
第二正极活性物质为化学式(2)所示的化合物：
Li 1+zMn cZ 2-cO 4-dB d     化学式(2)
化学式(2)中，-0.1≤z≤0.2，0<c≤2，0≤d<1，Z为Ni、Fe、Cr、Ti、Zn、V、Al、Mg、Zr及Ce中的一种或多种，B为S、N、F、Cl、Br及I中的一种或多种。
并且，正极极片的技术参数r满足：r＝R·P/C且0.04≤R·P/C≤10。
其中，R为正极极片的电阻，单位为Ω；P为正极极片的压实密度，单位为g/cm 3；C为正极极片的单面面密度，单位为g/1540.25mm 2。
在本文中，R·P/C的计算仅涉及数值的计算。举例来说，正极极片的电阻R为0.13Ω，正极极片的压实密度P为3.20g/cm 3，正极极片的单面面密度C为0.400g/1540.25mm 2，则R·P/C＝0.13×3.20/0.400＝1.04。
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。
正极极片的单面面密度C可以通过公式C＝1540.25m/A r计算得出，式中m为正极活性物质层的重量，单位为g；A r为正极活性物质层的面积，单位为mm 2。
正极极片的压实密度P可以通过公式P＝m/v计算得出，式中m为正极活性物质层的重量，单位为g；v为正极活性物质层的体积，单位为cm 3。其中正极活性物质层的体积v可以是正极活性物质层的面积A r与正极活性物质层的厚度之积。
本申请实施例的正极极片能够充分发挥第一正极活性物质和第二正极活性物质之间的协同效应，使正极活性物质具有较高的结构稳定性，并且正极活性物质表面电解液的副反应明显减少，有效抑制产气及减少产热量。同时，正极极片还具有较高的电子和离子传输性能。采用本申请实施例的正极极片，能在保证锂离子二次电池具有较高的比容量及能量密度的前提下，有效提高锂离子二次电池的安全性能、低温动力学性能、高温循 环性能及高温存储性能。
在本申请实施例的正极极片中，第一正极活性物质和第二正极活性物质之间的协同效应还能有效抑制第一正极活性物质在循环过程中的极化增大，并减小第二正极活性物质的姜-泰勒效应，从而减小正极极化。因此，正极容量损失明显减小，从而进一步提高锂离子二次电池的循环性能。
本申请实施例的正极极片具有较高的电子和离子传输性能，还使得锂离子二次电池具有较高的倍率性能及较低的低温直流内阻，从而进一步提高锂离子二次电池的低温动力学性能。
因此，采用本申请实施例的正极极片，能使锂离子二次电池同时兼顾较高的安全性能、低温动力学性能、高温循环性能及高温存储性能。
另外，正极极片的电阻、压实密度及单面面密度均是锂离子二次电池设计及制作中的关键技术参数。正极极片的电阻增大，表现为锂离子二次电池的倍率性能及循环性能降低。正极极片的压实密度过大或过小都会使电池的倍率性能及循环性能变差。正极极片的单面面密度过大，电池的循环寿命降低，还会影响电池的倍率性能，特别是使得电池高倍率下的放电容量降低；而正极极片的单面面密度过小，意味着相同电池容量下，集流体及隔膜的长度增加，增大电池的欧姆内阻。这就要求在电池的设计及制作中对这些参数能够进行综合地监控及判断。本申请提出的技术参数r主要反映的是正极极片本身的特性，用来监控及判断正极极片的设计及制作，能够保证正极极片达到预期的设计值，以使锂离子二次电池的电化学性能达到预期的效果。
通过将正极极片的电阻、压实密度及单面面密度统一为一个技术参数r，还有利于行业制定标准。
进一步优选地，正极极片的技术参数r满足：0.5≤r≤8。
正极极片的电阻R优选为R<5Ω，更优选为R≤1Ω。这有利于提高锂离子二次电池的倍率性能及循环性能。
正极极片的压实密度P优选为2.6g/cm 3≤P≤3.5g/cm 3。这有利于正极极片中电子和离子的迁移，从而提高锂离子二次电池的倍率性能及循环性能。
正极极片的单面面密度C优选为0.25g/1540.25mm 2≤C≤0.40g/1540.25mm 2。这能在保证充放电容量的前提下，提高锂离子二次电池的倍率性能及循环性能。
正极活性物质层的厚度优选为116μm～185μm，更优选为116μm～149μm。这有利于正极极片获得较低的电阻，并保证电池具有较高的充放电容量。
在正极活性物质中，第一正极活性物质和第二正极活性物质的重量比优选为0.05:1～19:1，进一步优选为0.4:1～19:1，更优选为1:1～4:1。该正极活性物质具有更高的结构稳定性，并进一步减少电解液在正极活性物质表面的副反应。并且，该正极活性物质还能够减少锰溶出，一方面减少因正极活性物质结构破坏造成的正极容量损失及正极阻抗增大；另一方面减少因溶出的锰沉积在负极表面而造成的负极阻抗增大及负极析锂现象。因此，采用该正极活性物质的正极极片能更好地改善锂离子二次电池的安全性能、低温动力学性能、高温循环性能及高温存储性能。
正极活性物质层中第二正极活性物质的重量百分含量优选为4wt％～95wt％，更优选为4wt％～67wt％。
在正极活性物质中，第一正极活性物质的平均粒径D v50优选为4μm～18μm且平均粒径D v90优选为10μm～24μm。更优选地，第一正极活性物质的平均粒径D v50为8μm～16μm且平均粒径D v90为10μm～20μm。
第二正极活性物质的平均粒径D v50优选为8μm～20μm且平均粒径D v90优选为14μm～35μm。更优选地，第二正极活性物质的平均粒径D v50为11μm～16μm且平均粒径D v90为18μm～30μm。
采用具有上述粒径分布的第一正极活性物质和第二正极活性物质，能进一步改善正极极片的电子和离子传输性能，从而进一步提高锂离子二次电池的低温动力学性能及高温循环性能。
在正极活性物质中，第一正极活性物质的BET比表面积优选为0.4m 2/g～1m 2/g，更优选为0.5m 2/g～0.6m 2/g。
第二正极活性物质的BET比表面积优选为0.4m 2/g～0.7m 2/g，更优选为0.5m 2/g～0.7m 2/g。
本申请实施例的正极极片，正极活性物质层中还可以包括导电剂和/或粘结剂。本申请对导电剂及粘结剂的种类不做具体限制，可以根据实际需求进行选择。
作为示例，正极活性物质层的导电剂可以是石墨、超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中一种或多种；正极活性物质层的粘结剂可以是丁苯橡胶(SBR)、水性丙烯酸树脂(water-based acrylic resin)、羧甲基纤维素(CMC)、聚偏二氟乙烯(PVDF)、聚四氟乙烯(PTFE)、聚乙烯醇缩丁醛(PVB)、乙烯-醋酸乙烯酯共聚物(EVA)及聚乙烯醇(PVA)中的一种或多种。
在一些可选的实施方式中，导电剂与正极活性物质的质量比大于或等于1.5:95.5。这有利于获得较低的正极极片电阻。
在一些可选的实施方式中，粘结剂在正极活性物质层中的重量百分比小于或等于2wt％。这有利于获得较低的正极极片电阻。
正极集流体可以采用金属箔材或多孔金属板，例如使用铝、铜、镍、钛或银等金属或它们的合金的箔材或多孔板，如铝箔。
正极集流体的厚度优选为5μm～20μm，进一步优选为6μm～18μm，更优选为8μm～16μm。
接下来说明本申请实施例提供的一种正极极片的制备方法。
本申请的正极极片可以采用涂布方式制备。例如先将正极浆料涂布于正极集流体的至少一个表面上，获得正极活性物质涂层，之后经过烘干、冷压等工序，即在正极集流体上获得正极活性物质层，得到正极极片。
在一些实施例中，本申请实施例提供的一种正极极片的制备方法包括以下步骤：
S100、将正极活性物质、粘结剂、导电剂及溶剂按照预定比例混合，溶剂可以是N-甲基吡咯烷酮(NMP)，将混合物料搅拌至均一体系，获得正极浆料。
在步骤S100，正极活性物质包括前文所述的第一正极活性物质和第二正极活性物质。其中，第一正极活性物质和第二正极活性物质可以是同时加入的，当然也可以是按先后顺序加入；第一正极活性物质和第二正极活 性物质各自独立地为一次性加入，当然也可以各自独立地为分批次加入。
在一些优选的实施例中，先将第一正极活性物质与粘结剂、导电剂及有机溶剂进行搅拌混合，制成稳定的预浆料；再在预浆料中加入第二正极活性物质，进行搅拌混合，制成正极浆料。这样能够使正极活性物质层内部颗粒分布均匀，避免导电剂发生团聚，从而形成均匀分布的导电网络。因此，正极极片的电阻得到大幅度降低，从而能提高电池的动力学性能及循环性能。
在步骤S100，还可以加入其它添加剂，如碳酸锂Li 2CO 3。加入碳酸锂能进一步改善电池的过充性能。当步骤S100中添加碳酸锂时，添加量可以满足碳酸锂占正极活性物质层的重量百分含量为1wt％～5wt％，如1wt％～1.5wt％。
在步骤S100，可以使用本领域已知的方法及装置进行混合物料的搅拌。例如将物料加入真空搅拌机中进行搅拌混合，真空压力为小于等于-20KPa(表压)。搅拌过程的调粘步骤中，公转速率为20RPM～30RPM、自转速率为1100RPM～1300RPM，如公转速率为25RPM、自转速率为1200RPM，整个搅拌过程的时间为4h～7h。其中RPM(Revolutions Per Minute)即转每分，表征每分钟的旋转次数。
正极浆料的粘度优选为大于等于5000mPa·s，例如5000mPa·s～7000mPa·s，再例如5000mPa·s～6000mPa·s。
正极浆料的密度优选为大于1.25kg/L。这有利于使浆料搅拌更为均匀，导电剂不易发生团聚，从而有利于使电池具有较高的倍率性能及循环性能。
S200、将正极浆料均匀涂布于正极集流体上，得到初始正极极片。
S300、将初始正极极片经烘干、冷压等工序，得到正极极片。
在一些可选的实施例中，可以是将初始正极极片转移至烘箱进行烘干，烘干的温度为120℃～140℃，如130℃。
冷压工序可以使用本领域已知的方法及装置进行，本领域技术人员可以根据正极极片的压实密度P的需求进行选择。
通过上述制备方法能够实现本申请实施例的正极极片。
锂离子二次电池
本申请实施例还提供一种锂离子二次电池，其包括正极极片、负极极片、隔离膜和电解液。
正极极片采用本申请实施例提供的任意一种正极极片。
负极极片可以是金属锂片，也可以是包括负极集流体及设置于负极集流体至少一个表面上的负极活性物质层。
负极活性物质层通常包含负极活性物质以及可选的导电剂、粘结剂和增稠剂。作为示例，负极活性物质可以是天然石墨、人造石墨、中间相微碳球(MCMB)、硬碳、软碳、硅、硅-碳复合物、SiO、Li-Sn合金、Li-Sn-O合金、Sn、SnO、SnO 2、尖晶石结构的钛酸锂Li 4Ti 5O 12、Li-Al合金及金属锂中的一种或多种；负极活性物质层的导电剂可以是石墨、超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的一种或多种；负极活性物质层的粘结剂可以是丁苯橡胶(SBR)、聚偏二氟乙烯(PVDF)、聚四氟乙烯(PTFE)、聚乙烯醇缩丁醛(PVB)、水性丙烯酸树脂(water-based acrylic resin)及羧甲基纤维素(CMC)中的一种或多种；负极活性物质层的增稠剂可以是羧甲基纤维素(CMC)。但本申请并不限定于这些材料，本申请还可以使用可被用作锂离子二次电池负极活性物质、导电剂、粘结剂和增稠剂的其它材料。
负极集流体可以使用金属箔材或多孔金属板等材料，例如使用铜、镍、钛或铁等金属或它们的合金的箔材或多孔板，如铜箔。
负极极片可以按照本领域常规方法制备。通常将负极活性物质及可选的导电剂、粘结剂和增稠剂分散于溶剂中，溶剂可以是N-甲基吡咯烷酮(NMP)或去离子水，形成均匀的负极浆料；将负极浆料涂覆在负极集流体上，经烘干、冷压等工序得到负极极片。
对隔离膜没有特别的限制，可以选用任意公知的具有电化学稳定性和化学稳定性的多孔结构隔离膜。例如，隔离膜选自玻璃纤维、无纺布、聚乙烯(PE)、聚丙烯(PP)及聚偏二氟乙烯(PVDF)中的一种或多种的单层或多层薄膜。
电解液包括有机溶剂和电解质锂盐。本申请对有机溶剂和电解质锂盐的种类不做具体限制，可以根据实际需求进行选择。
作为示例，有机溶剂可以选自碳酸亚乙酯(EC)、碳酸亚丙基酯(PC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)、碳酸二甲酯(DMC)、碳酸二丙酯(DPC)、碳酸甲丙酯(MPC)、碳酸乙丙酯(EPC)、碳酸亚丁酯(BC)、氟代碳酸亚乙酯(FEC)、甲酸甲酯(MF)、乙酸甲酯(MA)、乙酸乙酯(EA)、乙酸丙酯(PA)、丙酸甲酯(MP)、丙酸乙酯(EP)、丙酸丙酯(PP)、丁酸甲酯(MB)、丁酸乙酯(EB)、1,4-丁内酯(GBL)、环丁砜(SF)、二甲砜(MSM)、甲乙砜(EMS)及二乙砜(ESE)中的一种或多种，优选为两种以上。
电解质锂盐可以选自LiPF 6(六氟磷酸锂)、LiBF 4(四氟硼酸锂)、LiClO 4(高氯酸锂)、LiAsF 6(六氟砷酸锂)、LiFSI(双氟磺酰亚胺锂)、LiTFSI(双三氟甲磺酰亚胺锂)、LiTFS(三氟甲磺酸锂)、LiDFOB(二氟草酸硼酸锂)、LiBOB(二草酸硼酸锂)、LiPO 2F 2(二氟磷酸锂)、LiDFOP(二氟二草酸磷酸锂)及LiTFOP(四氟草酸磷酸锂)中的一种或多种。
电解液中还可选地包括添加剂，其可以是任意可被用作锂离子二次电池的添加剂，本申请不做具体限制，可以根据实际需求进行选择。作为示例，添加剂可以选自碳酸亚乙烯酯(VC)、碳酸乙烯亚乙酯(VEC)、氟代碳酸亚乙酯(FEC)、丁二腈(SN)、己二腈(ADN)、1,3-丙烯磺酸内酯(PST)、磺酸酯环状季铵盐、三(三甲基硅烷)磷酸酯(TMSP)及三(三甲基硅烷)硼酸酯(TMSB)中的一种或多种。
电解液可以按照本领域常规的方法制备。可以是将有机溶剂和电解质锂盐及可选的添加剂混合均匀，得到电解液。其中各物料的添加顺序并没有特别的限制。例如，将电解质锂盐及可选的添加剂加入到有机溶剂中混合均匀，得到电解液。其中可以是先将电解质锂盐加入有机溶剂中，然后再将可选的添加剂分别或同时加入有机溶剂中。
将正极极片、隔离膜及负极极片按顺序堆叠好，使隔离膜处于正极极片与负极极片之间起到隔离的作用，得到电芯，也可以是经卷绕后得到电 芯；将电芯置于包装外壳中，注入电解液并封口，得到锂离子二次电池。
由于使用了本申请实施例的正极极片，使本申请的锂离子二次电池同时兼顾较高的安全性能、低温动力学性能、高温循环性能及高温存储性能。
实施例
下述实施例更具体地描述了本申请公开的内容，这些实施例仅仅用于阐述性说明，因为在本申请公开内容的范围内进行各种修改和变化对本领域技术人员来说是明显的。除非另有声明，以下实施例中所报道的所有份、百分比、和比值都是基于重量计，而且实施例中使用的所有试剂都可商购获得或是按照常规方法进行合成获得，并且可直接使用而无需进一步处理，以及实施例中使用的仪器均可商购获得。
实施例1
正极极片的制备
将第一正极活性物质LiNi 0.5Co 0.2Mn 0.3O 2、第二正极活性物质LiMn 2O 4、粘结剂PVDF、导电炭黑、碳纳米管(CNT)导电浆料及Li 2CO 3进行混合，其中LiNi 0.5Co 0.2Mn 0.3O 2、LiMn 2O 4、PVDF、导电炭黑、CNT及Li 2CO 3的重量比为90.25:4.75:1.1:2.3:0.4:1.2，加入溶剂NMP，在真空搅拌作用下搅拌至均一透明状体系，获得正极浆料，正极浆料的粘度为5100mPa·s，搅拌时间为4h；将正极浆料均匀涂覆于正极集流体铝箔上，之后转移至烘箱干燥，烘干温度为130℃，再经过冷压、分切，得到正极极片。正极活性物质层中第一正极活性物质LiNi 0.5Co 0.2Mn 0.3O 2的重量百分含量为90.25wt％，正极活性物质层中第二正极活性物质LiMn 2O 4的重量百分含量为4.75wt％。
负极极片的制备
将负极活性物质人造石墨、增稠剂羧甲基纤维素钠(CMC)、粘结剂丁苯橡胶(SBR)按照质量比98:1:1进行混合，加入溶剂去离子水，在真空搅拌机作用下获得负极浆料；将负极浆料均匀涂覆在负极集流体铜箔上；之后转移至烘箱干燥，烘干温度为120℃，再经过冷压、分切，得到 负极极片。
电解液的制备
将碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)及碳酸二乙酯(DEC)按照体积比为1:1:1混合均匀，得到有机溶剂。将1mol/L的LiPF 6溶解于上述有机溶剂中，混合均匀，得到电解液。
锂离子二次电池的制备
将正极极片、隔离膜、负极极片依次层叠设置，隔离膜采用厚度为14μm的聚丙烯(PP)薄膜(型号为A273，由Celgard公司提供)，其处于正极极片和负极极片之间起到隔离作用，然后卷绕成方形的裸电芯，焊接极耳，将裸电芯装入外壳中，注入电解液并封口，之后经过静置、化成、整形等工序，得到锂离子二次电池。
实施例2～9
与实施例1不同的是，调整正极极片的制备步骤中的相关参数，详见表1。
对比例1
与实施例1不同的是，正极极片中正极活性物质仅含有LiMn 2O 4。
对比例2
与实施例1不同的是，正极极片中正极活性物质仅含有LiNi 0.8Co 0.1Mn 0.1O 2。
对比例3
与实施例1不同的是，正极极片的正极活性物质层中正极活性物质、导电炭黑、CNT的重量百分含量分别为90wt％、5.7wt％、2wt％。
对比例4
与实施例1不同的是，正极浆料的粘度为4000mPa·s，搅拌时间为6h。
对比例5
与实施例1不同的是，正极浆料的粘度为4300mPa·s，搅拌时间为5.5h。
测试部分
(1)正极极片的电阻R测试
采用日置BT3562型内阻测试仪进行正极极片的电阻，包括：将正极极片夹持于内阻测试仪的两个导电端子之间，并施加压力固定，测试正极极片的电阻R，其中导电端子的直径为14mm，施加压力为15MPa～27MPa，采点时间的范围为5s～17s。
(2)锂离子二次电池的高温循环性能测试
在60℃下，将锂离子二次电池以1C倍率恒流充电至4.2V，再恒压充电至电流小于等于0.05C，再以1C倍率恒流放电至3.0V，此为一个充放电循环，记录锂离子二次电池第1次循环的放电容量。将锂离子二次电池按照上述方法进行充放电循环，记录每一次循环的放电容量，直至锂离子二次电池的放电容量衰减至第1次循环的放电容量的80％，记录充放电循环次数。
(3)锂离子二次电池的倍率性能测试
在25℃下，将锂离子二次电池以0.33C的倍率恒流充电至4.2V，再恒压充电至电流小于等于0.05C，之后静置30分钟，再以1C倍率恒流放电至3.0V，测试得到锂离子二次电池1C倍率放电容量。
在25℃下，将锂离子二次电池以0.33C的倍率恒流充电至4.2V，再恒压充电至电流小于等于0.05C，之后静置30分钟，再以3C倍率恒流放电至3.0V，测试得到锂离子二次电池3C倍率放电容量。
锂离子二次电池3C倍率放电容量保持率(％)＝3C倍率放电容量/1C倍率放电容量×100％。
(4)锂离子二次电池的高温存储性能测试
在25℃下，将锂离子二次电池以0.33C的倍率恒流充电至4.2V，再恒压充电至电流小于等于0.05C，再以0.33C倍率恒流放电至3.0V，测试得到锂离子二次电池的初始放电容量。
在25℃下，将锂离子二次电池以0.33C的倍率恒流充电至4.2V，再恒压充电至电流小于等于0.05C，之后将满充状态的锂离子二次电池置入60℃的烘箱中存储60天。
取出高温存储60天后的锂离子二次电池、并自然降温至25℃，以 0.33C倍率恒流放电至3.0V，之后以0.33C的倍率恒流充电至4.2V，再恒压充电至电流小于等于0.05C，再以0.33C倍率恒流放电至3.0V，测试得到锂离子二次电池高温存储60天后的放电容量。
锂离子二次电池高温存储60天后的容量保持率(％)＝高温存储60天后的放电容量/初始放电容量×100％。
(5)锂离子二次电池的低温直流内阻(DCR)性能测试
在25℃下，将锂离子二次电池以1C的倍率恒流充电至4.2V，再恒压充电至电流小于等于0.05C，之后以1C的倍率恒流放电，将锂离子二次电池的荷电状态(SOC)调整至满充容量的50％，再调节锂离子二次电池的温度为-25℃，静置2h，然后以0.36C恒流放电10s，测试得到DCR值。
实施例1～9和对比例1～5的测试结果示于表2。
表1
Figure PCTCN2019105727-appb-000001
表1中，第一正极活性物质的重量百分含量和第二正极活性物质的重量百分含量均为在正极活性物质层中的重量百分含量。
表2
  R·P/C 倍率性能/％ 高温循环次数 高温存储性能/％ 低温DCR/mΩ
实施例1 0.50 95 789 91.0 652.0
实施例2 1.04 95 664 90.0 659.0
实施例3 9.92 92 456 88.0 666.0
实施例4 4.48 92 420 88.0 675.0
实施例5 0.04 94 280 86.2 686.7
实施例6 4.83 95 310 87.2 706.1
实施例7 7.14 94 300 86.5 690.0
实施例8 5.72 93 230 87.0 346.0
实施例9 4.72 90 446 88.8 327.5
对比例1 19.88 85 130 76.9 732.1
对比例2 22.22 87 150 77.6 370.0
对比例3 0.03 87 240 83.0 720.0
对比例4 18.00 85 200 85.0 730.0
对比例5 25.78 88 90 80.0 358.0
通过上述实施例和对比例可知，当正极极片的正极活性物质为第一正极活性物质和第二正极活性物质的混合体系，且正极极片满足0.04≤R·P/C≤10时，在提高锂离子二次电池安全性能的同时，还提高了锂离子二次电池的低温动力学性能、高温存储性能及高温循环性能。而当R·P/C<0.04时，以及当R·P/C>10时，锂离子二次电池的倍率性能较低以及低温DCR较高，电池的低温动力学性能受到影响，电池的高温存储性能及高温循环性能也明显恶化。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到各种等效的修改或替换，这些修改或替换都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以权利要求的保护范围为准。

Claims (10)

  1. 一种正极极片，包括正极集流体以及设置于所述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化学式(1)所示的第一正极活性物质和化学式(2)所示的第二正极活性物质，
    Li 1+xNi aMe bM 1-a-bO 2-yA y  化学式(1)
    所述化学式(1)中，-0.1≤x≤0.2，0<a<1，0<b<1，0<a+b<1，0≤y<0.2，Me和M各自独立地为Co、Mn、Fe、Cr、Ti、Zn、V、Al、Zr及Ce中的一种或多种、且Me与M不相同，A为S、N、F、Cl、Br及I中的一种或多种，
    Li 1+zMn cZ 2-cO 4-dB d  化学式(2)
    所述化学式(2)中，-0.1≤z≤0.2，0<c≤2，0≤d<1，Z为Ni、Fe、Cr、Ti、Zn、V、Al、Mg、Zr及Ce中的一种或多种，B为S、N、F、Cl、Br及I中的一种或多种；
    其中，所述正极极片满足式(1)，
    0.04≤R·P/C≤10  式(1)
    所述式(1)中，R为所述正极极片的电阻，单位为Ω；P为所述正极极片的压实密度，单位为g/cm 3；C为所述正极极片的单面面密度，单位为g/1540.25mm 2。
  2. 根据权利要求1所述的正极极片，其中，所述正极极片满足式(2)，
    0.5≤R·P/C≤8  式(2)。
  3. 根据权利要求1所述的正极极片，其中，所述正极极片的电阻R为R<5Ω，优选为R≤1Ω。
  4. 根据权利要求1所述的正极极片，其中，所述正极极片的压实密度P为2.6g/cm 3≤P≤3.5g/cm 3。
  5. 根据权利要求1所述的正极极片，其中，所述正极极片的单面面密度C为0.25g/1540.25mm 2≤C≤0.40g/1540.25mm 2。
  6. 根据权利要求1所述的正极极片，其中，所述第一正极活性物质和 所述第二正极活性物质的重量比为0.05:1～19:1，优选为0.4:1～19:1。
  7. 根据权利要求1或6所述的正极极片，其中，所述正极活性物质层中所述第二正极活性物质的重量百分含量为4wt％～95wt％，优选为4wt％～67wt％。
  8. 根据权利要求1所述的正极极片，其中，
    所述第一正极活性物质的平均粒径D v50为4μm～18μm且平均粒径D v90为10μm～24μm，优选地所述第一正极活性物质的平均粒径D v50为8μm～16μm且平均粒径D v90为10μm～20μm；和/或，
    所述第二正极活性物质的平均粒径D v50为8μm～20μm且平均粒径D v90为14μm～35μm，优选地所述第二正极活性物质的平均粒径D v50为11μm～16μm且平均粒径D v90为18μm～30μm。
  9. 根据权利要求1所述的正极极片，其中，所述化学式(1)中，0.5≤a<1，Me和M各自独立地为Co、Mn及Al中的一种或多种。
  10. 一种锂离子二次电池，包括正极极片、负极极片、隔离膜和电解液，所述正极极片为如权利要求1至9任一项所述的正极极片。
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Families Citing this family (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114556614A (zh) 2019-12-02 2022-05-27 宁德时代新能源科技股份有限公司 一种用于二次电池的正极极片、二次电池、电池模块、电池包和装置
CN112151851B (zh) * 2020-10-30 2022-03-29 珠海冠宇电池股份有限公司 一种能够降低内部温升的叠片式锂离子电池用叠芯
CN114982011B (zh) * 2020-12-24 2024-04-05 宁德时代新能源科技股份有限公司 电池模组及其制造方法和设备、电池包及用电装置
CN113036082B (zh) * 2021-03-05 2022-06-03 江苏正力新能电池技术有限公司 一种正极极片、正极极片的制备方法和锂离子二次电池
WO2022198651A1 (zh) * 2021-03-26 2022-09-29 宁德新能源科技有限公司 一种正极极片、包含该正极极片的电化学装置和电子装置
EP4089766B1 (en) * 2021-03-26 2023-11-15 Ningde Amperex Technology Ltd. Positive electrode plate, electrochemical device comprising same, and electronic device
CN115882044A (zh) * 2021-05-07 2023-03-31 宁德新能源科技有限公司 电化学装置和电子装置
EP4152479A4 (en) 2021-07-30 2023-09-13 Contemporary Amperex Technology Co., Limited BATTERY GROUP, BATTERY PACK AND ELECTRICAL DEVICE
CN114766067A (zh) * 2021-10-25 2022-07-19 宁德新能源科技有限公司 正极极片、电化学装置及电子装置
EP4280310A4 (en) * 2022-03-31 2024-04-10 Contemporary Amperex Technology Co Ltd POSITIVE ELECTRODE SHEET, SECONDARY BATTERY, BATTERY MODULE, BATTERY PACK AND ELECTRICAL DEVICE
CN114824441A (zh) * 2022-05-09 2022-07-29 江苏正力新能电池技术有限公司 一种电芯、电池模组和电池包
CN115588825A (zh) * 2022-09-26 2023-01-10 湖北亿纬动力有限公司 锂离子二次电池的化成方法及锂离子二次电池
CN116888795A (zh) * 2022-10-28 2023-10-13 宁德时代新能源科技股份有限公司 一种电池单体、电池及用电装置
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
CN116598421B (zh) * 2023-07-18 2023-10-10 江苏正力新能电池技术有限公司 一种正极极片及锂离子电池

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002100358A (ja) * 2000-09-25 2002-04-05 Seimi Chem Co Ltd リチウム二次電池
CN103165935A (zh) * 2011-12-08 2013-06-19 索尼公司 电极、二次电池、电池组、电动车辆以及电力储存***
CN103972471A (zh) * 2014-04-19 2014-08-06 东风商用车有限公司 一种大倍率磷酸铁锂电池的正极极片及其制作方法
JP2015046282A (ja) * 2013-08-28 2015-03-12 新神戸電機株式会社 リチウムイオン電池

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100907621B1 (ko) * 2006-08-28 2009-07-15 주식회사 엘지화학 두 성분의 도전재를 포함하는 양극 합제 및 그것으로구성된 리튬 이차전지
CN102195032B (zh) 2010-12-16 2016-05-04 东莞新能源电子科技有限公司 锂离子电池极片制备方法
CN102064326B (zh) 2010-12-16 2016-01-06 东莞新能源电子科技有限公司 锂离子电池正负极材料分散剂
CN103515616A (zh) 2012-06-27 2014-01-15 万向电动汽车有限公司 一种锂离子动力电池正极片及其制备方法
WO2016104024A1 (ja) * 2014-12-26 2016-06-30 日立化成株式会社 リチウムイオン電池
JP2017075377A (ja) * 2015-10-15 2017-04-20 株式会社コベルコ科研 ＬｉＣｏＯ２含有焼結体およびＬｉＣｏＯ２含有スパッタリングターゲット、並びにＬｉＣｏＯ２含有焼結体の製造方法
CN108292751B (zh) * 2016-05-30 2021-06-04 日立金属株式会社 锂离子二次电池用正极活性物质和使用了其的锂离子二次电池
US10170789B2 (en) * 2017-05-31 2019-01-01 Nanotek Instruments, Inc. Method of producing a shape-conformable alkali metal battery having a conductive and deformable quasi-solid polymer electrode
CN107768733B (zh) * 2017-10-13 2019-12-03 江苏海四达电源股份有限公司 一种锂电池及其制备方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002100358A (ja) * 2000-09-25 2002-04-05 Seimi Chem Co Ltd リチウム二次電池
CN103165935A (zh) * 2011-12-08 2013-06-19 索尼公司 电极、二次电池、电池组、电动车辆以及电力储存***
JP2015046282A (ja) * 2013-08-28 2015-03-12 新神戸電機株式会社 リチウムイオン電池
CN103972471A (zh) * 2014-04-19 2014-08-06 东风商用车有限公司 一种大倍率磷酸铁锂电池的正极极片及其制作方法

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP3680965A4 *

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