WO2026007658A1 - 二次电池和电子设备 - Google Patents

二次电池和电子设备

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Publication number
WO2026007658A1
WO2026007658A1 PCT/CN2025/100488 CN2025100488W WO2026007658A1 WO 2026007658 A1 WO2026007658 A1 WO 2026007658A1 CN 2025100488 W CN2025100488 W CN 2025100488W WO 2026007658 A1 WO2026007658 A1 WO 2026007658A1
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WO
WIPO (PCT)
Prior art keywords
secondary battery
lithium
electrolyte
positive electrode
current collector
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.)
Pending
Application number
PCT/CN2025/100488
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English (en)
French (fr)
Inventor
徐晴
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.)
Ningde Amperex Technology Ltd
Original Assignee
Ningde Amperex Technology Ltd
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Filing date
Publication date
Application filed by Ningde Amperex Technology Ltd filed Critical Ningde Amperex Technology Ltd
Publication of WO2026007658A1 publication Critical patent/WO2026007658A1/zh
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • 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
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • 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
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0567—Liquid materials characterised by the additives
    • 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
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H01M4/665—Composites
    • 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

  • This application relates to the field of electrochemical energy storage, and in particular to a secondary battery and an electronic device using the secondary battery.
  • Rechargeable batteries have seen rapid development in the fields of new energy vehicles and large-scale energy storage. With the diversification of application areas, usage regions, and application scenarios of end products, the market demands higher and higher performance from rechargeable batteries. How to provide a rechargeable battery with more stable and efficient performance under high and low temperature conversion conditions has become an urgent problem to be solved.
  • This application provides a secondary battery and an electronic device.
  • the first aspect of this application provides a secondary battery, including a positive electrode, a negative electrode, and an electrolyte.
  • the positive electrode includes a composite current collector and a positive electrode material layer disposed on at least one surface of the composite current collector.
  • the positive electrode material layer includes a lithium nickel cobalt manganese oxide compound. Based on the total molar amount of metal elements other than lithium, the molar percentage of nickel in the lithium nickel cobalt manganese oxide compound is X, where X > 80%.
  • the electrolyte includes ethylene carbonate and fluoroethylene carbonate. Based on the mass of the electrolyte, the mass percentage of ethylene carbonate is Y1, and the mass percentage of fluoroethylene carbonate is Y2, where 1 ⁇ Y1/Y2 ⁇ 35.
  • the composite current collector and the high-nickel ternary cathode material work together, and cooperate with ethylene carbonate and fluoroethylene carbonate present in the electrolyte in a specific ratio, which can improve the capacity retention and lithium-ion acceptance of the secondary battery after high and low temperature impact tests.
  • 5% ⁇ Y1 ⁇ 40% can further improve the capacity retention and lithium-ion acceptance of the secondary battery after high and low temperature shock tests.
  • 10% ⁇ Y1 ⁇ 20% can further improve the capacity retention and lithium-ion acceptance of the secondary battery after high and low temperature shock tests.
  • 0.3% ⁇ Y2 ⁇ 7% can further improve the capacity retention and lithium-ion acceptance of the secondary battery after high and low temperature shock tests.
  • the composite current collector includes a polymer support layer and a metal conductive layer disposed on at least one surface of the polymer support layer. Meeting the above conditions can further improve the capacity retention and lithium-ion acceptance of the secondary battery after high and low temperature shock tests.
  • the polymer support layer comprises polyethylene terephthalate and/or polypropylene. Meeting the above conditions can further improve the capacity retention and lithium-ion acceptance of the secondary battery after high and low temperature shock tests.
  • the thickness of the polymer support layer is T, where 3 ⁇ m ⁇ T ⁇ 12 ⁇ m. Meeting these conditions can further improve the capacity retention and lithium-ion acceptance of the secondary battery after high and low temperature shock tests.
  • the electrolyte further includes 1,3,6-hexanetrionitrile, wherein the mass percentage of 1,3,6-hexanetrionitrile is Y3, based on the mass of the electrolyte, 0.1% ⁇ Y3 ⁇ 4%, and 1 ⁇ Y2/Y3 ⁇ 60. Meeting these conditions enhances the synergistic effect of the composite current collector, the high-nickel ternary cathode material, and the specific proportions of ethylene carbonate and fluoroethylene carbonate, further improving the capacity retention and lithium-ion acceptance of the secondary battery after high and low temperature impact tests.
  • the electrolyte also includes lithium salicylate. Meeting the above conditions can enhance the synergistic effect of the composite current collector, the high-nickel ternary cathode material, and the specific ratio of ethylene carbonate and fluoroethylene carbonate, further improving the capacity retention and lithium-ion acceptance of the secondary battery after high and low temperature shock tests.
  • the electrolyte also includes butene sulfite. Meeting the above conditions can further improve the capacity retention and lithium-ion acceptance of the secondary battery after high and low temperature shock tests.
  • the negative electrode sheet includes a negative electrode material layer, which comprises graphite and silicon materials, wherein the graphite includes artificial graphite and/or natural graphite.
  • this negative electrode is applied in the battery of this application, it can better synergize with the positive electrode and electrolyte to improve the performance of the secondary battery.
  • a second aspect of this application provides an electronic device including a secondary battery.
  • One embodiment of this application provides a secondary battery, which includes a casing, an electrode assembly, and an electrolyte. Both the electrode assembly and the electrolyte are located within the casing.
  • the outer casing can be a packaging bag sealed with an encapsulating film (such as aluminum-plastic film), for example, a pouch battery for a secondary battery.
  • an encapsulating film such as aluminum-plastic film
  • the secondary battery can also be a steel-cased battery, an aluminum-cased battery, etc.
  • the electrode assembly includes a positive electrode, a negative electrode, and a separator, with the separator disposed between the positive and negative electrode.
  • the electrode assembly can be a stacked structure, formed by alternating layers of the positive electrode, separator, and negative electrode. In other embodiments, the electrode assembly can also be a wound structure, formed by winding layers of the positive electrode, separator, and negative electrode.
  • the positive electrode includes a composite current collector and a positive electrode material layer disposed on at least one surface of the composite current collector.
  • the positive electrode material layer includes a lithium nickel cobalt manganese oxide compound. Based on the total molar amount of metal elements other than lithium, the molar percentage of nickel in the lithium nickel cobalt manganese oxide compound is X, where X > 80%.
  • the electrolyte comprises ethylene carbonate (EC), fluoroethylene carbonate (FEC), 1,3,6-hexanetrionitrile, and lithium salicylate. Based on the mass of the electrolyte, the mass percentage of ethylene carbonate is Y1, the mass percentage of fluoroethylene carbonate is Y2, and 1 ⁇ Y1/Y2 ⁇ 35. Based on the mass of the electrolyte, the mass percentage of 1,3,6-hexanetrionitrile is Y3, 0.1% ⁇ Y3 ⁇ 4%, and 1 ⁇ Y2/Y3 ⁇ 60.
  • the positive electrode and electrolyte in the secondary battery provided in this application can work synergistically to improve the stability of the secondary battery, thereby improving the capacity retention and lithium-ion acceptance after high and low temperature shock tests. It is speculated that the positive electrode and electrolyte systems in this application can improve the bonding force between the composite current collector and the high-nickel ternary positive electrode material, and, supported by the composite current collector, enhance the temperature difference resistance of the ethylene carbonate and fluoroethylene carbonate films formed at the high-nickel ternary positive electrode interface. This synergistic effect allows the secondary battery to withstand the shock of high and low temperature switching.
  • 1,3,6-hexanetrionitrile and lithium salicylate can further strengthen the synergistic effect between the positive electrode (including the composite current collector and the high-nickel ternary material) and the electrolyte (including ethylene carbonate and fluoroethylene carbonate), further improving the capacity retention and lithium-ion acceptance of the secondary battery after high and low temperature shock tests.
  • Lithium nickel cobalt manganese oxide compounds include lithium nickel cobalt manganese oxide and its derivatives, such as coating materials or derivatives doped with other metal elements.
  • lithium nickel cobalt manganese oxide compounds can be LiNi ⁇ sub>0.8 ⁇ /sub>Co ⁇ sub>0.1 ⁇ /sub>Mn ⁇ sub>0.1 ⁇ /sub> O ⁇ sub>2 ⁇ /sub> or LiNi ⁇ sub>0.88 ⁇ /sub> Co ⁇ sub>0.1 ⁇ /sub> Mn ⁇ sub>0.02 ⁇ /sub> O ⁇ sub> 2 ⁇ /sub>.
  • Lithium nickel cobalt manganese oxide derivatives can be Li ⁇ sub>0.8 ⁇ /sub>Ni ⁇ sub>0.8982 ⁇ /sub>Co ⁇ sub>0.0589 ⁇ /sub>Mn ⁇ sub>0.0409 ⁇ /sub>Zr ⁇ sub>0.002 ⁇ /sub>O ⁇ sub> 2 ⁇ /sub>.
  • X can be 82%, 85%, 87%, 90%, 92%, 95%, or any value within the range of any two of the above values.
  • the values of Y1/Y2 can be 1, 2, 5, 7, 9, 12, 15, 17, 19, 22, 25, 30, 35, or any value within the range of any two of the above values.
  • 5% ⁇ Y1 ⁇ 40% can further improve the capacity retention and lithium-ion acceptance of the secondary battery after high and low temperature shock tests.
  • Y1 can be 5%, 7%, 10%, 15%, 20%, 22%, 25%, 30%, 32%, 35%, 37%, 40%, or any value within the range of any two of the above values.
  • 10% ⁇ Y1 ⁇ 20% is more conducive to improving the capacity retention and lithium-ion acceptance of secondary batteries after high and low temperature shock tests.
  • Y2 can be 0.3%, 0.5%, 1%, 3%, 4%, 5%, 7%, or any value within the range of any two of the above values.
  • Y3 can be 0.1%, 0.2%, 0.5%, 0.7%, 1%, 1.2%, 1.5%, 2%, 2.2%, 2.5%, 3%, 3.2%, 3.5%, 4%, or any value within the range of any two of the above values.
  • the ratio of Y2 to Y3 can be 1, 1.5, 1.7, 2, 2.5, 3, 4, 5, 5.5, 6, 10, 20, 30, 40, 50, 60, or any value within the range of any two of the above values.
  • the electrolyte further includes butene sulfite. This is beneficial for further improving the capacity retention and lithium-ion acceptance of the secondary battery after high and low temperature shock tests.
  • the mass percentage of butene sulfite is 0.1% to 0.5%, which is beneficial for improving the capacity retention and lithium-ion acceptance of the secondary battery after high and low temperature shock tests.
  • the mass percentage of butene sulfite can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, or any value within the range of any two of the above values.
  • the addition of lithium salicylate to the electrolyte is beneficial for further improving the capacity retention and lithium-ion acceptability of the secondary battery after high and low temperature shock tests.
  • the mass percentage of lithium salicylate is 0.2% to 0.5%, which is beneficial for improving the capacity retention and lithium-ion acceptability of the secondary battery after high and low temperature shock tests.
  • the mass percentage of lithium salicylate can be 0.2%, 0.25%, 0.3%, 0.4%, 0.45%, 0.5%, or any value within the range of any two of the above values.
  • the electrolyte includes the ethylene carbonate, fluoroethylene carbonate, 1,3,6-hexanetrionitrile, butene sulfite, and lithium salicylate described above.
  • the electrolyte further includes an organic solvent, which includes, but is not limited to: propylene carbonate (PC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), propylene carbonate, or ethyl propionate.
  • organic solvent includes, but is not limited to: propylene carbonate (PC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), propylene carbonate, or ethyl propionate.
  • the organic solvent further includes ether solvents, including at least one of 1,3-dioxapentane (DOL) and ethylene glycol dimethyl ether (DME) in some optional embodiments.
  • ether solvents including at least one of 1,3-dioxapentane (DOL) and ethylene glycol dimethyl ether (DME) in some optional embodiments.
  • the electrolyte may further comprise a lithium salt, which includes at least one of organic or inorganic lithium salts.
  • the lithium salt includes, but is not limited to: lithium hexafluorophosphate ( LiPF6 ), lithium tetrafluoroborate ( LiBF4 ), lithium difluorophosphate ( LiPO2F2 ), lithium bis( trifluoromethanesulfonyl )imide LiN( CF3SO2 ) 2 (LiTFSI), lithium bis(fluorosulfonyl)imide Li(N( SO2F ) 2 ) (LiFSI), lithium bis ( fluorosulfonyl ) imide LiB( C2O4 ) 2 (LiBOB), or lithium difluorooxalate borate LiBF2 ( C2O4 ) (LiDFOB).
  • the additive includes at least one of adiponitrile.
  • the composite current collector includes a polymer support layer and a metal conductive layer disposed on at least one surface of the polymer support layer.
  • the polymer support layer provides good structural strength, which can improve the structural strength of the composite current collector, thereby facilitating further improvement in the capacity retention and lithium-ion acceptance of the secondary battery after high and low temperature impact tests.
  • the polymer support layer comprises polyethylene terephthalate and/or polypropylene.
  • the conductive metal layer may include at least one of aluminum or an aluminum alloy.
  • the thickness of the polymer support layer is T, where 3 ⁇ m ⁇ T ⁇ 12 ⁇ m. Within this range, the polymer support layer exhibits good structural strength, supports the metal conductive layer, improves the structural stability of the composite current collector, and further enhances the capacity retention and lithium-ion acceptability of the secondary battery after high and low temperature impact tests.
  • T can be 3 ⁇ m, 5 ⁇ m, 7 ⁇ m, 10 ⁇ m, 12 ⁇ m, or any value within the range of any two of the above values.
  • the positive electrode material layer also includes an adhesive for bonding the positive electrode active material particles to facilitate the formation of the film layer, and also to improve the bonding force between the positive electrode material layer and the positive electrode current collector.
  • the adhesive may include, but is not limited to, at least one of polyvinyl alcohol, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymers, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, or nylon.
  • the positive electrode material layer may also include a conductive material, which includes, but is not limited to, carbon-based materials, metal-based materials, conductive polymers, or any combination thereof.
  • carbon-based materials may include, but are not limited to, natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, or any combination thereof.
  • metal-based materials may include, but are not limited to, metal powder or metal fibers, and in some optional embodiments, copper, nickel, aluminum, or silver.
  • the conductive polymer may be a polyphenylene derivative.
  • the negative electrode material layer comprises graphite and silicon.
  • Graphite includes synthetic graphite and/or natural graphite.
  • Silicon materials include at least one of (compounds of silicon-based substances and carbon-based substances) or silicon oxide (SiOx, 0 ⁇ x ⁇ 2).
  • Silicon-based substances can be silicon particles, silicon alloy particles, etc.
  • graphite possesses a certain degree of flexibility, its combination with silicon-carbon composite materials can mitigate the overall volume expansion of the anode material layer. Furthermore, using both graphite and silicon-carbon composite materials as anode active materials can fully leverage the advantages of both materials to achieve better electrochemical performance.
  • the mass percentage of graphite in the negative electrode material layer is from 35 wt.% to 95 wt.%.
  • the cycle performance of the negative electrode material layer can be further improved, thereby improving the cycle performance of the secondary battery.
  • the negative electrode current collector can be at least one of copper foil, nickel foil, stainless steel foil, titanium foil or carbon-based current collector, or any composite current collector disclosed in the prior art, or a current collector formed by combining the aforementioned conductive foil and polymer substrate in some optional embodiments, but not limited to.
  • the negative electrode material layer also includes a binder to bond the negative electrode active material particles, thereby facilitating the formation of the film layer and improving the bonding force between the negative electrode material layer and the negative electrode current collector.
  • the binder may include, but is not limited to, polyvinyl alcohol, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymers, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, or nylon, etc.
  • the negative electrode material layer may further include a conductive material, which includes, but is not limited to, carbon-based materials, metal-based materials, conductive polymers, or any combination thereof.
  • carbon-based materials may include, but are not limited to, natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, or any combination thereof.
  • metal-based materials may include, but are not limited to, metal powder or metal fibers, and in some optional embodiments, copper, nickel, aluminum, or silver.
  • the conductive polymer may be a polyphenylene derivative.
  • the negative electrode material layer may also include a dispersant, which may include at least one of sodium carboxymethyl cellulose, lithium carboxymethyl cellulose, carboxymethyl cellulose, lithium hydroxypropyl carboxymethyl cellulose, sodium hydroxypropyl carboxymethyl cellulose, lithium hydroxyethyl carboxymethyl cellulose, sodium hydroxyethyl carboxymethyl cellulose, or hydroxyethyl carboxymethyl cellulose.
  • a dispersant which may include at least one of sodium carboxymethyl cellulose, lithium carboxymethyl cellulose, carboxymethyl cellulose, lithium hydroxypropyl carboxymethyl cellulose, sodium hydroxypropyl carboxymethyl cellulose, lithium hydroxyethyl carboxymethyl cellulose, sodium hydroxyethyl carboxymethyl cellulose, or hydroxyethyl carboxymethyl cellulose.
  • the material and shape of the separator used in the secondary battery of this application are not particularly limited, and can be any technology disclosed in the prior art.
  • the separator comprises a polymer or inorganic material formed from a material stable to the electrolyte of this application.
  • the separator may include a substrate layer and a surface treatment layer.
  • the substrate layer is a nonwoven fabric, membrane, or composite membrane with a porous structure, and the material of the substrate layer is selected from at least one of polyethylene, polypropylene, polyethylene terephthalate, and polyimide.
  • a polypropylene porous membrane, a polyethylene porous membrane, a polypropylene nonwoven fabric, a polyethylene nonwoven fabric, or a polypropylene-polyethylene-polypropylene porous composite membrane may be selected.
  • a surface treatment layer is disposed on at least one surface of the substrate layer.
  • the surface treatment layer may be a polymer layer or an inorganic layer, or a layer formed by a mixture of polymer and inorganic material.
  • the inorganic layer includes inorganic particles and a binder.
  • the inorganic particles are selected from at least one of alumina, silicon oxide, magnesium oxide, titanium oxide, hafnium dioxide, tin oxide, cerium dioxide, nickel oxide, zinc oxide, calcium oxide, zirconium oxide, yttrium oxide, silicon carbide, boehmite, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, and barium sulfate.
  • the binder is selected from at least one of polyvinylidene fluoride, a copolymer of polyvinylidene fluoride and hexafluoropropylene, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyvinyl alkoxy, polymethyl methacrylate, polytetrafluoroethylene, and polyhexafluoropropylene.
  • the polymer layer contains a polymer, and the polymer material is selected from at least one of polyamide, polyacrylonitrile, acrylate polymer, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyvinyl alkoxy, polyvinylidene fluoride, and poly(vinylidene fluoride-hexafluoropropylene).
  • the aforementioned secondary batteries are used in electronic devices to power loads within those devices.
  • These electronic devices may include, but are not limited to, laptops, pen-based computers, mobile computers, e-book players, portable telephones, portable fax machines, portable copiers, portable printers, stereo headphones, video recorders, LCD TVs, portable cleaners, portable CD players, mini CDs, transceivers, electronic notebooks, calculators, memory cards, portable recorders, radios, backup power supplies, motors, automobiles, motorcycles, electric bicycles, bicycles, lighting fixtures, toys, game consoles, clocks, power tools, flashlights, cameras, large household batteries, and lithium-ion capacitors, etc.
  • LiNi 0.88 Co 0.1 Mn 0.02 O 2 , Super-P, and polyvinylidene fluoride were mixed with N-methylpyrrolidone (NMP) in a mass ratio of 96:2:2 and stirred until homogeneous to obtain a positive electrode slurry.
  • NMP N-methylpyrrolidone
  • This positive electrode slurry was coated onto a 12 ⁇ m composite aluminum foil (commercially available, a composite current collector made by depositing aluminum layers on both sides of polyethylene terephthalate (PET) using an advanced vacuum deposition process), dried, cold-pressed, and then cut and welded to obtain the positive electrode sheet.
  • PET polyethylene terephthalate
  • a 7-micron porous polyethylene polymer film was used as the separator.
  • the obtained positive electrode, separator, and negative electrode are wound in sequence and placed in an outer packaging foil, leaving the electrolyte injection port. Electrolyte is poured in through the injection port, the battery is sealed, and then processed through formation, capacity testing, and other procedures to produce a secondary battery.
  • Example 2 The difference between Examples 2 to 21 and Example 1 is that, except for adjusting the electrolyte parameters according to Table 1, they are the same as in Example 1.
  • Example 22 to 27 The difference between Examples 22 to 27 and Example 15 is that, except for adjusting the relevant parameters of the composite current collector according to Table 1, they are the same as in Example 1.
  • Comparative Example 1 was identical to Example 1 except that it used a conventional positive electrode current collector with a thickness of 10 ⁇ m. Comparative Examples 2 to 5 were identical to Example 1 except that the electrolyte preparation parameters were adjusted according to Table 1.
  • Capacity retention rate (Discharge capacity of the 200th cycle / Discharge capacity of the first cycle) ⁇ 100%.
  • Capacity retention rate is greater than 85%
  • Capacity retention rate is greater than or equal to 80% and less than 85%;
  • the presence of a certain amount of 1,3,6-hexanetrionitrile in the electrolyte can further improve the capacity retention and lithium-ion acceptance of the secondary battery after high and low temperature shock tests.
  • the polymer support layer of the composite current collector meets the scope defined in this application, it can further improve the capacity retention and lithium-ion acceptance of the secondary battery after high and low temperature shock tests.

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Abstract

本申请提供一种二次电池和电子设备，二次电池包括正极极片、负极极片和电解液，正极极片包括复合集流体和设置于复合集流体的至少一个表面上的正极材料层，正极材料层包括镍钴锰酸锂化合物，基于除锂之外的金属元素的总摩尔量，镍钴锰酸锂化合物中镍元素的摩尔百分含量为X，X＞80％；电解液包括碳酸乙烯酯和氟代碳酸乙烯酯，基于电解液的质量，碳酸乙烯酯的质量百分含量为Y1，氟代碳酸乙烯酯的质量百分含量为Y2，1≤Y1/Y2≤35。本申请能够改善二次电池在高低温冲击试验后的容量保持率和锂离子接受性。

Description

二次电池和电子设备 技术领域
本申请涉及电化学储能领域，尤其是涉及一种二次电池和应用所述二次电池的电子设备。
背景技术
二次电池在新能源汽车和大规模储能领域得到了迅猛发展。随着终端产品的应用领域、使用地域以及使用场景的多元化，市场对二次电池的性能要求越来越高，如何提供一种在高低温转换条件下性能更加稳定高效的二次电池，成为了目前迫切需要解决的问题。
发明内容
本申请提供一种二次电池和电子设备。
本申请第一方面提供一种二次电池，包括正极极片、负极极片和电解液，正极极片包括复合集流体和设置于复合集流体的至少一个表面上的正极材料层，正极材料层包括镍钴锰酸锂化合物，基于除锂之外的金属元素的总摩尔量，镍钴锰酸锂化合物中镍元素的摩尔百分含量为X，X＞80％；电解液包括碳酸乙烯酯和氟代碳酸乙烯酯，基于电解液的质量，碳酸乙烯酯的质量百分含量为Y1，氟代碳酸乙烯酯的质量百分含量为Y2，1≤Y1/Y2≤35。
本申请中，复合集流体和高镍三元正极材料共同作用，并与电解液中以特定比例存在的碳酸乙烯酯和氟代碳酸乙烯酯互相配合，能够改善二次电池在高低温冲击试验后的容量保持率和锂离子接受性。
基于第一方面，在一些可能的实施方式中，5％≤Y1≤40％，能够进一步改善二次电池在高低温冲击试验后的容量保持率和锂离子接受性。
基于第一方面，在一些可能的实施方式中，10％≤Y1≤20％，能够进一步改善二次电池在高低温冲击试验后的容量保持率和锂离子接受性。
基于第一方面，在一些可能的实施方式中，0.3％≤Y2≤7％，能够进一步改善二次电池在高低温冲击试验后的容量保持率和锂离子接受性。
基于第一方面，在一些可能的实施方式中，复合集流体包括聚合物支撑层以及设置于聚合物支撑层的至少一个表面上的金属导电层。满足上述条件，能够进一步改善二次电池在高低温冲击试验后的容量保持率和锂离子接受性。
基于第一方面，在一些可能的实施方式中，聚合物支撑层包括聚对苯二甲酸乙二醇酯或/和聚丙烯。满足上述条件，能够进一步改善二次电池在高低温冲击试验后的容量保持率和锂离子接受性。
基于第一方面，在一些可能的实施方式中，聚合物支撑层的厚度为T，3μm≤T≤12μm。满足上述条件，能够进一步改善二次电池在高低温冲击试验后的容量保持率和锂离子接受性。
基于第一方面，在一些可能的实施方式中，电解液还包括1,3,6-己烷三腈，基于电解液的质量，1,3,6-己烷三腈的质量百分含量为Y3，0.1％≤Y3≤4％，1≤Y2/Y3≤60。满足上述条件，能够加强复合集流体和高镍三元正极材料以及特定比例的碳酸乙烯酯和氟代碳酸乙烯酯的协同作用，进一步改善二次电池在高低温冲击试验后的容量保持率和锂离子接受性。
基于第一方面，在一些可能的实施方式中，电解液还包括水杨酸锂。满足上述条件，能够加强复合集流体和高镍三元正极材料以及特定比例的碳酸乙烯酯和氟代碳酸乙烯酯的协同作用，进一步改善二次电池在高低温冲击试验后的容量保持率和锂离子接受性。
基于第一方面，在一些可能的实施方式中，电解液还包括亚硫酸丁烯酯。满足上述条件，能够进一步改善二次电池在高低温冲击试验后的容量保持率和锂离子接受性。
基于第一方面，在一些可能的实施方式中，负极极片包括负极材料层，负极材料层包括石墨和硅材料，石墨包括人造石墨和/或天然石墨。该负极应用于本申请的电池中，能够与正极和电解液更好地协同作用以提升二次电池性能。
本申请第二方面提供一种电子设备，包括二次电池。
具体实施方式
下面对本申请实施例中的技术方案进行清楚、详细地描述，显然，所描述的实施例是本申请一部分实施例，而不是全部的实施例。除非另有定义，本文所使用的所有的技术和科学术语与属于本申请的技术领域的技术人员通常理解的含义相同。在本申请的说明书中所使用的术语只是为了描述具体的实施例的目的，不是旨在于限制本申请。
本申请一实施方式提供一种二次电池，其包括外壳、电极组件和电解液。电极组件和电解液均位于外壳内。
外壳可以是采用封装膜(如铝塑膜)封装得到的包装袋，如二次电池为软包电池。在另一些实施例中，二次电池也可以是钢壳电池、铝壳电池等。
电极组件包括正极极片、负极极片和隔离膜，隔离膜设于正极极片和负极极片之间。电极组件可以是叠片式结构，其由正极极片、隔离膜和负极极片交替层叠形成。在另一些实施例中，电极组件还可以是卷绕结构，其由正极极片、隔离膜和负极极片层叠后卷绕形成。
正极极片包括复合集流体和设置于复合集流体的至少一个表面上的正极材料层，正极材料层包括镍钴锰酸锂化合物，基于除锂之外的金属元素的总摩尔量，镍钴锰酸锂化合物中镍元素的摩尔百分含量为X，X＞80％；
电解液包括碳酸乙烯酯(EC)、氟代碳酸乙烯酯(FEC)、1,3,6-己烷三腈和水杨酸锂，基于电解液的质量，碳酸乙烯酯的质量百分含量为Y1，氟代碳酸乙烯酯的质量百分含量为Y2，1≤Y1/Y2≤35；基于电解液的质量，1,3,6-己烷三腈的质量百分含量为Y3，0.1％≤Y3≤4％，1≤Y2/Y3≤60。
本申请提供的二次电池中的正极与电解液能够协同作用以提高二次电池稳定性，从而改善二次电池在高低温冲击试验后的容量保持率和锂离子接受性。猜测本申请中的正极体系与电解液体系，可以提高复合集流体与高镍三元正极材料之间的结合力，并在复合集流体的支撑下增强本申请电解液中的碳酸乙烯酯和氟代碳酸乙烯酯在高镍三元正极界面成膜的抗温差作用，上述协同效果使二次电池可耐受高低温转换的冲击。加入的1,3,6-己烷三腈和水杨酸锂能够进一步加强包括复合集流体和高镍三元的正极与包括碳酸乙烯酯和氟代碳酸乙烯酯的电解液之间的协同效果，进一步改善二次电池在高低温冲击试验后的容量保持率和锂离子接受性。
镍钴锰酸锂化合物包括镍钴锰酸锂以及镍钴锰酸锂衍生物，镍钴锰酸锂衍生物如包覆材料或掺杂有其他金属元素的衍生物。例如，镍钴锰酸锂化合物可以为LiNi0.8Co0.1Mn0.1O2、LiNi0.88Co0.1Mn0.02O2。镍钴锰酸锂衍生物可以为Li0.8Ni0.8982Co0.0589Mn0.0409Zr0.002O2。
在一些可选的实施方式中，X可以为82％、85％、87％、90％、92％、95％或在上述任意两个数值所组成的范围内的任一值。Y1/Y2的数值可以为1、2、5、7、9、12、15、17、19、22、25、30、35或在上述任意两个数值所组成的范围内的任一值。
在一些实施例中，5％≤Y1≤40％。能够进一步改善二次电池在高低温冲击试验后的容量保持率和锂离子接受性。
在一些可选的实施方式中，Y1可以为5％、7％、10％、15％、20％、22％、25％、30％、32％、35％、37％、40％或在上述任意两个数值所组成的范围内的任一值。
在一些实施例中，10％≤Y1≤20％，更利于改善二次电池在高低温冲击试验后的容量保持率和锂离子接受性。
在一些实施例中，0.3％≤Y2≤7％。能够进一步改善二次电池在高低温冲击试验后的容量保持率和锂离子接受性。
在一些可选的实施方式中，Y2可以为0.3％、0.5％、1％、3％、4％、5％、7％或在上述任意两个数值所组成的范围内的任一值。
在一些可选的实施方式中，Y3可以为0.1％、0.2％、0.5％、0.7％、1％、1.2％、1.5％、2％、2.2％、2.5％、3％、3.2％、3.5％、4％或在上述任意两个数值所组成的范围内的任一值。Y2/Y3的比值可以为1、1.5、1.7、2、2.5、3、4、5、5.5、6、10、20、30、40、50、60或在上述任意两个数值所组成的范围内的任一值。
在一些实施例中，电解液还包括亚硫酸丁烯酯。利于进一步改善二次电池在高低温冲击试验后的容量保持率和锂离子接受性。基于电解液的质量，亚硫酸丁烯酯的质量百分含量为0.1％至0.5％，利于改善二次电池在高低温冲击试验后的容量保持率和锂离子接受性。在一些实施例中，亚硫酸丁烯酯的质量百分含量可以为0.1％、0.2％、0.3％、0.4％、0.5％或在上述任意两个数值所组成的范围内的任一值。
在一些实施例中，在电解液中，加入水杨酸锂利于进一步改善二次电池在高低温冲击试验后的容量保持率和锂离子接受性。基于电解液的质量，水杨酸锂的质量百分含量为0.2％至0.5％，利于改善二次电池在高低温冲击试验后的容量保持率和锂离子接受性。在一些实施例中，水杨酸锂的质量百分含量可以为0.2％、0.25％、0.3％、0.4％、0.45％、0.5％或在上述任意两个数值所组成的范围内的任一值。
电解液
根据本申请的一些实施方式，电解液包括上述所描述的碳酸乙烯酯、氟代碳酸乙烯酯、1,3,6-己烷三腈、亚硫酸丁烯酯和水杨酸锂。
在一些实施例中，电解液还包括有机溶剂，有机溶剂包括，但不限于：碳酸丙烯酯(PC)、碳酸二乙酯(DEC)、碳酸甲乙酯(EMC)、碳酸二甲酯(DMC)、碳酸亚丙酯或丙酸乙酯。
在一些实施例中，有机溶剂还包括醚类溶剂，在一些可选的实施方式中包括1，3-二氧五环(DOL)和乙二醇二甲醚(DME)中的至少一种。
在一些实施例中，电解液还可以包括锂盐，锂盐包括有机锂盐或无机锂盐中的至少一种。在一些实施例中，锂盐包括，但不限于：六氟磷酸锂(LiPF6)、四氟硼酸锂(LiBF4)、二氟磷酸锂(LiPO2F2)、双三氟甲烷磺酰亚胺锂LiN(CF3SO2)2(LiTFSI)、双(氟磺酰)亚胺锂Li(N(SO2F)2)(LiFSI)、双草酸硼酸锂LiB(C2O4)2(LiBOB)或二氟草酸硼酸锂LiBF2(C2O4)(LiDFOB)。在一些实施例中，添加剂包括己二腈中的至少一种。
正极极片
在一些实施例中，复合集流体包括聚合物支撑层以及设置于聚合物支撑层的至少一个表面上的金属导电层。采用聚合物支撑层具有良好的结构强度，能够提高复合集流体的结构强度，从而利于进一步改善二次电池在高低温冲击试验后的容量保持率和锂离子接受性。
在一些实施例中，聚合物支撑层包括聚对苯二甲酸乙二醇酯或/和聚丙烯。上述聚合物材料作为聚合物支撑层具有较好的热稳定性和力学性能。
金属导电层可以包括铝或铝合金中的至少一种。
在一些实施例中，聚合物支撑层的厚度为T，3μm≤T≤12μm。在上述范围内，利于使得聚合物支撑层具有良好的结构强度，支撑金属导电层，提高复合集流体的结构稳定性，利于进一步改善二次电池在高低温冲击试验后的容量保持率和锂离子接受性。在一些可选的实施方式中，T可以为3μm、5μm、7μm、10μm、12μm或在上述任意两个数值所组成的范围内的任一值。
正极材料层还包含粘合剂，用以粘结正极活性材料颗粒从而便于形成膜层，同时还能够提高正极材料层与正极集流体之间的结合力。在一些实施例中，粘合剂可包括但不仅限于聚乙烯醇、羟丙基纤维素、二乙酰基纤维素、聚氯乙烯、羧化的聚氯乙烯、聚氟乙烯、含亚乙基氧的聚合物、聚乙烯吡咯烷酮、聚氨酯、聚四氟乙烯、聚偏1,1-二氟乙烯、聚乙烯、聚丙烯、丁苯橡胶、丙烯酸(酯)化的丁苯橡胶、环氧树脂或尼龙等中的至少一种。
正极材料层还可包含导电材料，导电材料包括但不限于基于碳的材料、基于金属的材料、导电聚合物或其任意组合。在一些实施例中，基于碳的材料可包括但不仅限于自天然石墨、人造石墨、碳黑、乙炔黑、科琴黑、碳纤维或其任意组合。在一些实施例中，基于金属的材料可包括但不仅限于金属粉或金属纤维，在一些可选的实施方式中铜、镍、铝或银。在一些实施例中，导电聚合物可为聚亚苯基衍生物。
负极极片
在一些实施例中，负极材料层包括石墨和硅材料。石墨包括人造石墨和/或天然石墨。
硅材料包括(硅类物质和碳类物质的复合物)或硅氧化物(SiOx，0<x≤2)中的至少一种。硅类物质可为硅颗粒、硅合金颗粒等。
由于石墨具有一定的柔韧性，其与硅碳复合材料配合能够缓解负极材料层整体的体积膨胀。同时，石墨与硅碳复合材料同时作为负极活性材料还能够充分利用硅碳复合材料和石墨两者的优势以达到较好的电化学性能。
本申请中，负极材料层中石墨的质量占比为35wt.％到95wt.％，负极材料层中，石墨的质量占比在上述范围内，可以进一步地改善负极材料层的循环性能，从而提高二次电池的循环性能。
负极集流体可以使用铜箔、镍箔、不锈钢箔、钛箔或碳基集流体等中的至少一种，也可为任何现有技术中公开的复合集流体，在一些可选的实施方式中但不仅限于前述导电箔和聚合物基底结合形成的集流体。
负极材料层还包含粘结剂，用以粘结负极活性材料颗粒从而便于形成膜层，同时还能够提高负极材料层与负极集流体之间的结合力。在一些实施例中，粘结剂可包括但不仅限于聚乙烯醇、羟丙基纤维素、二乙酰基纤维素、聚氯乙烯、羧化的聚氯乙烯、聚氟乙烯、含亚乙基氧的聚合物、聚乙烯吡咯烷酮、聚氨酯、聚四氟乙烯、聚偏1,1-二氟乙烯、聚乙烯、聚丙烯、丁苯橡胶、丙烯酸(酯)化的丁苯橡胶、环氧树脂或尼龙等。
负极材料层还可包括导电材料，导电材料包括但不限于基于碳的材料、基于金属的材料、导电聚合物或其任意组合。在一些实施例中，基于碳的材料可包括但不仅限于自天然石墨、人造石墨、碳黑、乙炔黑、科琴黑、碳纤维或其任意组合。在一些实施例中，基于金属的材料可包括但不仅限于金属粉或金属纤维，在一些可选的实施方式中铜、镍、铝或银。在一些实施例中，导电聚合物可为聚亚苯基衍生物。
负极材料层还可包括分散剂，分散剂包括羧甲基纤维素钠、羧甲基纤维素锂、羧甲基纤维素、羟丙基羧甲基纤维素锂、羟丙基羧甲基纤维素钠、羟丙基羧甲基纤维素、羟乙基羧甲基纤维素锂、羟乙基羧甲基纤维素钠或羟乙基羧甲基纤维素中的至少一种。
隔离膜
本申请的二次电池中使用的隔离膜的材料和形状没有特别限制，其可为任何现有技术中公开的技术。在一些实施例中，隔离膜包括由对本申请的电解液稳定的材料形成的聚合物或无机物等。
在一些可选的实施方式中隔离膜可包括基材层和表面处理层。基材层为具有多孔结构的无纺布、膜或复合膜，基材层的材料选自聚乙烯、聚丙烯、聚对苯二甲酸乙二醇酯和聚酰亚胺中的至少一种。具体的，可选用聚丙烯多孔膜、聚乙烯多孔膜、聚丙烯无纺布、聚乙烯无纺布或聚丙烯-聚乙烯-聚丙烯多孔复合膜。
基材层的至少一个表面上设置有表面处理层，表面处理层可以是聚合物层或无机物层，也可以是混合聚合物与无机物所形成的层。无机物层包括无机颗粒和粘结剂，无机颗粒选自氧化铝、氧化硅、氧化镁、氧化钛、二氧化铪、氧化锡、二氧化铈、氧化镍、氧化锌、氧化钙、氧化锆、氧化钇、碳化硅、勃姆石、氢氧化铝、氢氧化镁、氢氧化钙和硫酸钡中的至少一种。粘结剂选自聚偏氟乙烯、偏氟乙烯-六氟丙烯的共聚物、聚酰胺、聚丙烯腈、聚丙烯酸酯、聚丙烯酸、聚丙烯酸盐、聚乙烯呲咯烷酮、聚乙烯烷氧、聚甲基丙烯酸甲酯、聚四氟乙烯和聚六氟丙烯中的至少一种。聚合物层中包含聚合物，聚合物的材料选自聚酰胺、聚丙烯腈、丙烯酸酯聚合物、聚丙烯酸、聚丙烯酸盐、聚乙烯呲咯烷酮、聚乙烯烷氧、聚偏氟乙烯、聚(偏氟乙烯-六氟丙烯)中的至少一种。
将上述二次电池应用于电子装置中，以为电子装置中的负载进行供电。其中，电子装置可包括但不仅限于笔记本电脑、笔输入型计算机、移动电脑、电子书播放器、便携式电话、便携式传真机、便携式复印机、便携式打印机、头戴式立体声耳机、录像机、液晶电视、手提式清洁器、便携CD机、迷你光盘、收发机、电子记事本、计算器、存储卡、便携式录音机、收音机、备用电源、电机、汽车、摩托车、助力自行车、自行车、照明器具、玩具、游戏机、钟表、电动工具、闪光灯、照相机、家庭用大型蓄电池和锂离子电容器等。
以下通过具体实施例和对比例对本申请进行说明。本领域技术人员应理解，本申请中描述的制备方法仅是实施例，其他任何合适的制备方法均在本申请的范围内。
实施例1
1.正极极片的制备
将LiNi0.88Co0.1Mn0.02O2、Super-P和聚偏氟乙烯按照96：2：2的质量比例与N-甲基吡咯烷酮(NMP)混合，搅拌均匀，得到正极浆料。将该正极浆料涂布在12μm的复合铝箔(商购获得，是一种以聚对苯二甲酸乙二醇酯(PET)作为基础材料，并在其正反两面上采用先进的真空镀膜工艺沉积金属铝层而制成的复合集流体)上，干燥，冷压，再经过裁片、焊接极耳，得到正极极片。
2.负极极片的制备
将人造石墨和SiO2(质量比90：10)、丁苯橡胶、羟乙基羧甲基纤维素钠按照96.5％:1.5％:2％的质量比例与去离子水混合，再加入三嗪化合物，搅拌均匀，得到浆料。将浆料涂布在9μm的铜箔上。干燥，冷压，再经过裁片、焊接极耳，得到负极极片。
3.电解液的制备
在干燥氩气环境下，将碳酸丙烯酯(PC)、碳酸二乙酯(DMC)和丙酸乙酯(EP)(重量比2:2:3)混合，加入LiPF6，其中LiPF6的浓度为12.5％，得到基础电解液。在基础电解液中按照表1所示含量加入碳酸乙烯酯(EC)和氟代碳酸乙烯酯(FEC)以及可选的其他物质得到不同实施例和对比例的电解液。
4.隔离膜的制备
以7微米的聚乙烯多孔聚合物薄膜作为隔离膜。
5.二次电池的制备
将得到的正极、隔离膜和负极按次序卷绕，置于外包装箔中，留下注液口。从注液口灌注电解液，封装，再经过化成、容量等工序制得二次电池。
实施例2至实施例21
实施例2至实施例21与实施例1的不同之处在于，除了按照表1调整电解液相关参数以外，其余与实施例1相同。
实施例22至实施例27
实施例22至实施例27与实施例15的不同之处在于，除了按照表1调整复合集流体相关参数以外，其余与实施例1相同。
对比例1至对比例5
对比例1除采用厚度为10μm的常规正极集流体外，其余与实施例1相同。对比例2至对比例5除了按照表1调整电解液相关制备参数以外，其余与实施例1相同。
测试方法
1.高低温冲击试验后的容量保持率
将制作的二次电池每组分别取3块，通过以下步骤分别对3块锂离子电池进行充电和放电，并计算二次电池的放电容量保持率。
首先，在25℃的环境中，进行首次充电和放电，先利用0.5C的电流进行恒流充电，充电至4.3V后进行恒压充电，然后在1C的电流下进行恒流放电，放电至2.8V，记录首次循环的放电容量；然后将锂离子电池置于-20℃的环境中进行100次充电和放电循环。低温循环结束后，在一小时之内将锂离子电池转置于45℃的环境中进行200次充电和放电循环，记录45℃条件下第200次循环的放电容量。
容量保持率＝(第200次循环的放电容量/首次循环的放电容量)×100％。
通过以下的基准进行评价。容量保持率越高，表示二次电池在高低温冲击试验后的性能越优异。
A：容量保持率大于85％；
B：容量保持率大于或等于80％且小于85％；
C：容量保持率大于或等于75％且小于80％；
D：容量保持率小于75％。
2.高低温冲击试验后的锂离子接受性
在35℃的环境下使制作的二次电池静置24小时后，在35℃的环境下，以1.0C的恒电流进行1小时的充电操作，测定高温充电容量(C0)。然后，在35℃的环境下，在以0.1C的恒电流进行放电达到3V的时刻，停止放电。接下来，在-15℃环境下，以1.0C的恒电流进行1小时的充电，测定低温充电容量(C1)。然后，算出C1相对于C0的比(C1/C0)，通过以下的基准进行评价。C1/C0的值越大，表示二次电池在低温下的锂离子接受性越优异。
A：C1/C0为0.65以上；
B：C1/C0为0.55以上且小于0.65；
C：C1/C0为0.5以上且小于0.55；
D：C1/C0小于0.5。
表1

上述表中“/”表示无相关参数。
相较于对比例，在实施例中，当复合集流体和高镍三元正极材料共同作用，并与电解液中以特定比例存在的碳酸乙烯酯和氟代碳酸乙烯酯互相配合作用下，能够改善二次电池在高低温冲击试验后的容量保持率和锂离子接受性。
特别地，当电解液中存在一定含量的1,3,6-己烷三腈，能够进一步改善二次电池在高低温冲击试验后的容量保持率和锂离子接受性。
特别地，当电解液中存在亚硫酸丁烯酯和/或水杨酸锂，能够进一步改善二次电池在高低温冲击试验后的容量保持率和锂离子接受性。
特别地，当复合集流体的聚合物支撑层满足本申请限定范围，能够进一步改善二次电池在高低温冲击试验后的容量保持率和锂离子接受性。
尽管已经演示和描述了说明性实施例，本领域技术人员应该理解上述实施例不能被解释为对本申请的限制，并且可以在不脱离本申请的原理及范围的情况下对实施例进行改变，替代和修改。

Claims (10)

  1. 一种二次电池，其特征在于，包括正极极片、负极极片和电解液，所述正极极片包括复合集流体和设置于所述复合集流体的至少一个表面上的正极材料层，所述正极材料层包括镍钴锰酸锂化合物，基于除锂之外的金属元素的总摩尔量，所述镍钴锰酸锂化合物中镍元素的摩尔百分含量为X，X＞80％；
    所述电解液包括碳酸乙烯酯和氟代碳酸乙烯酯，基于所述电解液的质量，所述碳酸乙烯酯的质量百分含量为Y1，所述氟代碳酸乙烯酯的质量百分含量为Y2，1≤Y1/Y2≤35。
  2. 如权利要求1所述的二次电池，其特征在于，所述二次电池满足以下条件中的至少一者：
    (1)5％≤Y1≤40％；
    (2)0.3％≤Y2≤7％。
  3. 如权利要求1或2所述的二次电池，其特征在于，所述复合集流体包括聚合物支撑层以及设置于所述聚合物支撑层的至少一个表面上的金属导电层。
  4. 如权利要求3所述的二次电池，其特征在于，所述聚合物支撑层包括聚对苯二甲酸乙二醇酯或/和聚丙烯。
  5. 如权利要求3或4所述的二次电池，其特征在于，所述聚合物支撑层的厚度为T，3μm≤T≤12μm。
  6. 如权利要求1至5中任一项所述的二次电池，其特征在于，所述电解液还包括亚硫酸丁烯酯。
  7. 如权利要求1至6中任一项所述的二次电池，其特征在于，所述电解液还包括1,3,6-己烷三腈，基于所述电解液的质量，所述1,3,6-己烷三腈的质量百分含量为Y3，0.1％≤Y3≤4％，1≤Y2/Y3≤60。
  8. 如权利要求1至7中任一项所述的二次电池，其特征在于，所述电解液还包括水杨酸锂。
  9. 如权利要求1至8中任一项所述的二次电池，其特征在于，所述负极极片包括负极材料层，所述负极材料层包括石墨和硅材料，所述石墨包括人造石墨和/或天然石墨。
  10. 一种电子设备，其特征在于，包括如权利要求1至9中任一项所述的二次电池。
PCT/CN2025/100488 2024-07-02 2025-06-11 二次电池和电子设备 Pending WO2026007658A1 (zh)

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