WO2023248829A1 - 二次電池用電解液および二次電池 - Google Patents

二次電池用電解液および二次電池 Download PDF

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WO2023248829A1
WO2023248829A1 PCT/JP2023/021489 JP2023021489W WO2023248829A1 WO 2023248829 A1 WO2023248829 A1 WO 2023248829A1 JP 2023021489 W JP2023021489 W JP 2023021489W WO 2023248829 A1 WO2023248829 A1 WO 2023248829A1
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secondary battery
negative electrode
compound
formula
electrolytic solution
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French (fr)
Japanese (ja)
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謙太郎 吉村
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Murata Manufacturing Co Ltd
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Murata Manufacturing Co Ltd
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Priority to JP2024528802A priority Critical patent/JP7750412B2/ja
Priority to CN202380032575.9A priority patent/CN118891764A/zh
Publication of WO2023248829A1 publication Critical patent/WO2023248829A1/ja
Priority to US18/901,749 priority patent/US20250030053A1/en
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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
    • 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
    • H01M10/0568—Liquid materials characterised by the solutes
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C69/00—Esters of carboxylic acids; Esters of carbonic or haloformic acids
    • C07C69/52—Esters of acyclic unsaturated carboxylic acids having the esterified carboxyl group bound to an acyclic carbon atom
    • C07C69/606—Esters of acyclic unsaturated carboxylic acids having the esterified carboxyl group bound to an acyclic carbon atom having only or additionally carbon-to-carbon triple bonds as unsaturation in the carboxylic acid moiety
    • 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
    • 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
    • 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
    • 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
    • H01M10/0569—Liquid materials characterised by the solvents
    • 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
    • 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
    • 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
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present technology relates to a secondary battery electrolyte and a secondary battery.
  • secondary batteries are being developed as a power source that is small and lightweight and provides high energy density.
  • This secondary battery includes a positive electrode, a negative electrode, and an electrolyte (electrolyte for secondary batteries), and various studies have been made regarding the configuration of the secondary battery.
  • the electrolytic solution contains an oxygen-containing aliphatic compound having an alkynyl group or an alkynylene group that does not have active hydrogen (see, for example, Patent Document 1). Further, a compound having a carbon-carbon triple bond is contained in the electrolytic solution (see, for example, Patent Document 2).
  • An electrolytic solution for a secondary battery and a secondary battery that can provide excellent battery characteristics are desired.
  • An electrolytic solution for a secondary battery according to an embodiment of the present technology contains a triple bond compound and a fluorophosphate.
  • the triple bond compound includes at least one of the compound represented by formula (1) and the compound represented by formula (2).
  • the fluorophosphate contains at least one of the compound represented by formula (3) and the compound represented by formula (4).
  • Each of R1 to R4 is an alkyl group.
  • a secondary battery according to an embodiment of the present technology includes a positive electrode, a negative electrode, and an electrolyte, and the electrolyte has the same configuration as the electrolyte for a secondary battery according to an embodiment of the present technology described above. It is something.
  • the electrolytic solution for a secondary battery or a secondary battery contains a triple bond compound and a fluorophosphate, excellent battery characteristics are obtained. be able to.
  • FIG. 1 is a cross-sectional view showing the configuration of a secondary battery in an embodiment of the present technology.
  • FIG. 2 is a cross-sectional view showing the configuration of the battery element shown in FIG. 1.
  • FIG. 3 is a cross-sectional view showing the configuration of a secondary battery in Modification 1.
  • FIG. FIG. 2 is a block diagram showing the configuration of an application example of a secondary battery.
  • Electrolyte for secondary batteries 1-1. Configuration 1-2. Manufacturing method 1-3. Action and effect 2. Secondary battery 2-1. Configuration 2-2. Operation 2-3. Manufacturing method 2-4. Action and effect 3. Modification example 4. Applications of secondary batteries
  • Electrolyte for secondary batteries First, an electrolytic solution for a secondary battery (hereinafter simply referred to as “electrolytic solution”) according to an embodiment of the present technology will be described.
  • the electrolytic solution described here is a liquid electrolyte used in a secondary battery, which is an electrochemical device.
  • the electrolytic solution may be used in electrochemical devices other than secondary batteries. Examples of other electrochemical devices include capacitors.
  • the electrolytic solution contains any one type or two or more types of triple bond compounds, and the triple bond compound is a compound having a carbon-carbon triple bond (-C ⁇ C-).
  • the triple bond compound contains one or both of the compound represented by formula (1) and the compound represented by formula (2). That is, the triple bond compound may contain only one of the compound shown in formula (1) and the compound shown in formula (2), or the triple bond compound may contain only one of the compound shown in formula (1) and the compound shown in formula (2). It may contain both of the compounds shown in (2).
  • first triple bond compound the compound represented by formula (1)
  • second triple bond compound the compound represented by formula (2)
  • Each of R1 to R4 is an alkyl group.
  • the reason why the electrolytic solution contains a triple bond compound is that in a secondary battery using the electrolytic solution, a decrease in discharge capacity is suppressed even if charging and discharging are repeated.
  • a film with excellent electrochemical stability is formed on the surface of the negative electrode 22 due to the synergistic effect of the triple bond compound and the fluorophosphate salt described below, so that the electrochemical durability of the film increases. improves.
  • This film is formed on the surface of the negative electrode 22 by stabilizing the secondary battery after assembly (initial charge/discharge treatment), as will be described later. Thereby, even if charging and discharging are repeated, the decomposition reaction of the electrolytic solution on the surface of the negative electrode 22 is suppressed, so that a decrease in discharge capacity is suppressed. In this case, the decomposition products of the film are also suppressed from seeping into the electrolyte during charging and discharging.
  • the above-mentioned film may be formed not only on the surface of the negative electrode 22 but also on the surface of the positive electrode 21. Thereby, even if charging and discharging are repeated, the decomposition reaction of the electrolytic solution on the surface of the positive electrode 21 is suppressed, and the corrosion of the positive electrode 21 is also suppressed.
  • each of R1 and R2 is not particularly limited as long as it is an alkyl group, as described above. In this case, the types of R1 and R2 may be the same or different.
  • the number of carbon atoms in the alkyl group is not particularly limited. Further, the alkyl group may be linear or branched.
  • alkyl group examples include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, and decyl group.
  • the number of carbon atoms in the alkyl group is preferably 1 to 7. This is because the number of carbon atoms in the alkyl group does not become too large, so that the solubility and compatibility of the first triple bond compound are improved.
  • R3 and R4 are the same as the details regarding R1 and R2 described above. Further, details regarding the alkyl group are as described above. That is, the number of carbon atoms in the alkyl group is not particularly limited, but is preferably 1 to 7. This is because the number of carbon atoms in the alkyl group does not become too large, so that the solubility and compatibility of the second triple bond compound are improved.
  • triple bond type compound Specific examples are as described below. However, since the specific example of the triple bond compound described below is just an example, the specific example of the triple bond compound may be a compound other than the compound described below.
  • first triple bond compound examples include compounds represented by each of formulas (1-1) to (1-10).
  • the compound shown in formula (1-1) is methyl 2-octinoate.
  • the compound represented by formula (1-2) is methyl 2-nonynoate.
  • the compound represented by formula (1-3) is methyl 2-hexanoate.
  • the compound represented by formula (1-4) is methyl 2-heptate.
  • the compound represented by formula (1-5) is ethyl 2-pentate.
  • the compound represented by formula (1-6) is ethyl 2-butyrate.
  • the compound represented by formula (1-7) is methyl 2-decanoate.
  • the compound represented by formula (1-8) is methyl 2-butyrate.
  • the compound represented by formula (1-9) is propyl 2-heptate.
  • the compound represented by formula (1-10) is butyl 2-heptate.
  • the second triple bond compound examples include compounds represented by formulas (2-1) to (2-8), respectively.
  • the compound represented by formula (2-1) is diisopropyl 2-butynedioate.
  • the compound represented by formula (2-2) is dipropyl 2-butynedioate.
  • the compound represented by formula (2-3) is dibutyl 2-butynedioate.
  • the compound represented by formula (2-4) is dipentyl 2-butynedioate.
  • the compound represented by formula (2-5) is dihexyl 2-butynedioate.
  • the compound represented by formula (2-6) is bis(2,2-dimethylpropyl) 2-butynedioate.
  • the compound represented by formula (2-7) is dioctyl 2-butynedioate.
  • the compound represented by formula (2-8) is bis(2-ethylhexyl) 2-butynedioate.
  • the content of the triple bond compound in the electrolytic solution is not particularly limited, but is preferably 0.01% by weight to 5% by weight. This is because the electrochemical durability of the coating formed on the surface of the negative electrode 22 is sufficiently improved.
  • the content of the triple bond compound in the electrolyte solution described above is the content of the first triple bond compound in the electrolyte solution. and the content of the second triple bond compound in the electrolyte.
  • the content of triple bond compounds is calculated by analyzing the electrolyte.
  • the electrolytic solution is recovered by disassembling the secondary battery.
  • Methods for analyzing the electrolyte are not particularly limited, but specifically include inductively coupled plasma (ICP) emission spectroscopy, nuclear magnetic resonance spectroscopy (NMR), and gas chromatography-mass spectrometry (GC-MS). One or more of these types.
  • ICP inductively coupled plasma
  • NMR nuclear magnetic resonance spectroscopy
  • GC-MS gas chromatography-mass spectrometry
  • the electrolytic solution contains one or more types of fluorophosphates, and the fluorophosphates contain fluorine (F), phosphorus (P), and oxygen (O) as constituent elements. It is a salt containing as.
  • the fluorophosphate contains one or both of the compound represented by formula (3) and the compound represented by formula (4). That is, the fluorophosphate may contain only one of the compound shown in formula (3) and the compound shown in formula (4), or the compound shown in formula (3) and the compound shown in formula (4) may be contained. It may contain both of the compounds shown in formula (4).
  • first fluorophosphate the compound represented by formula (3)
  • second fluorophosphate the compound represented by formula (4)
  • the electrolytic solution contains fluorophosphate contains fluorophosphate.
  • the electrochemical durability of the film formed on the surface of the negative electrode 22 is increased due to the synergistic effect of the fluorophosphate and the triple bond compound. This is because it will improve. Thereby, even if charging and discharging are repeated, the decomposition reaction of the electrolytic solution on the surface of the negative electrode 22 is suppressed, so that a decrease in discharge capacity is suppressed.
  • the fluorophosphate plays a role in forming a film on the surface of the negative electrode 22, and may also play a role as an electrolyte salt, which will be described later.
  • the first fluorophosphate is a so-called difluorophosphate.
  • the type of M1 is not particularly limited as long as it is an alkali metal element.
  • alkali metal elements include lithium, sodium, and potassium.
  • the alkali metal element is preferably lithium. This is because when the secondary battery is a lithium ion secondary battery, the first fluorophosphate also functions sufficiently as an electrolyte salt.
  • the second fluorophosphate is a so-called monofluorophosphate.
  • the type of alkali metal element is not particularly limited, but lithium is particularly preferred. This is because when the secondary battery is a lithium ion secondary battery, the second fluorophosphate also functions sufficiently as an electrolyte salt.
  • fluorophosphates are as described below. However, since the specific examples of the fluorophosphate described below are just a series, the specific examples of the fluorophosphate may be compounds other than the compounds described below.
  • first fluorophosphate examples include lithium difluorophosphate, sodium difluorophosphate, and potassium difluorophosphate.
  • the second fluorophosphate include dilithium monofluorophosphate, disodium monofluorophosphate, and dipotassium monofluorophosphate.
  • the content of fluorophosphate in the electrolytic solution is not particularly limited, but is preferably 0.01% to 2% by weight. This is because the electrochemical durability of the coating formed on the surface of the negative electrode 22 is sufficiently improved.
  • the content of the fluorophosphate in the electrolytic solution is equal to the content of the first fluorophosphate in the electrolytic solution. It is the sum of the salt content and the second fluorophosphate content in the electrolyte.
  • the electrolytic solution may further contain a solvent.
  • This solvent contains one or more types of non-aqueous solvents (organic solvents), and the electrolytic solution containing the non-aqueous solvent is a so-called non-aqueous electrolytic solution.
  • Non-aqueous solvents include esters and ethers, and more specifically include carbonate ester compounds, carboxylic acid ester compounds, and lactone compounds.
  • Carbonate ester compounds include cyclic carbonate esters and chain carbonate esters. Specific examples of cyclic carbonate esters include ethylene carbonate and propylene carbonate. Specific examples of chain carbonate esters include dimethyl carbonate, diethyl carbonate, and ethylmethyl carbonate.
  • the carboxylic acid ester compound is a chain carboxylic acid ester.
  • chain carboxylic acid esters include methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, propyl propionate, trimethylethyl acetate, methyl butyrate, and ethyl butyrate.
  • Lactone compounds include lactones. Specific examples of lactones include ⁇ -butyrolactone and ⁇ -valerolactone.
  • the ethers may include 1,2-dimethoxyethane, tetrahydrofuran, 1,3-dioxolane, and 1,4-dioxane.
  • the electrolytic solution may further contain an electrolyte salt.
  • This electrolyte salt is a light metal salt such as a lithium salt.
  • lithium salts include lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium trifluoromethanesulfonate (LiCF 3 SO 3 ), and lithium bis(fluorosulfonyl)imide (LiN).
  • the content of the electrolyte salt is not particularly limited, but specifically, it is 0.3 mol/kg to 3.0 mol/kg relative to the solvent. This is because high ionic conductivity can be obtained.
  • the electrolytic solution may further contain any one type or two or more types of additives.
  • the additive contains one or more of unsaturated cyclic carbonate, fluorinated cyclic carbonate, and cyanated cyclic carbonate. This is because the electrochemical stability of the electrolytic solution is improved. This further suppresses the decomposition reaction of the electrolytic solution during charging and discharging, thereby further suppressing the decrease in discharge capacity even if charging and discharging are repeated.
  • the unsaturated cyclic carbonate ester is a cyclic carbonate ester containing an unsaturated carbon bond (carbon-carbon double bond).
  • the number of unsaturated carbon bonds is not particularly limited, and may be one or two or more.
  • This unsaturated cyclic carbonate ester contains one or more of a vinylene carbonate compound, a vinylethylene carbonate compound, and a methylene ethylene carbonate compound.
  • the vinylene carbonate compound is an unsaturated cyclic carbonate ester having a vinylene carbonate type structure.
  • vinylene carbonate compounds include vinylene carbonate (1,3-dioxol-2-one), methyl vinylene carbonate (4-methyl-1,3-dioxol-2-one), and ethyl vinylene carbonate (4-ethyl-2-one).
  • 1,3-dioxol-2-one 1,3-dioxol-2-one), 4,5-dimethyl-1,3-dioxol-2-one, 4,5-diethyl-1,3-dioxol-2-one, 4-fluoro-1,3 -dioxol-2-one and 4-trifluoromethyl-1,3-dioxol-2-one.
  • the vinyl ethylene carbonate compound is an unsaturated cyclic carbonate ester having a vinyl ethylene carbonate type structure.
  • vinyl ethylene carbonate compounds include vinyl ethylene carbonate (4-vinyl-1,3-dioxolan-2-one), 4-methyl-4-vinyl-1,3-dioxolan-2-one, 4-ethyl -4-vinyl-1,3-dioxolan-2-one, 4-n-propyl-4-vinyl-1,3-dioxolan-2-one, 5-methyl-4-vinyl-1,3-dioxolan-2 -one, 4,4-divinyl-1,3-dioxolan-2-one and 4,5-divinyl-1,3-dioxolan-2-one.
  • the methylene ethylene carbonate compound is an unsaturated cyclic carbonate ester having a methylene ethylene carbonate type structure.
  • methylene ethylene carbonate compounds include methylene ethylene carbonate (4-methylene-1,3-dioxolan-2-one), 4,4-dimethyl-5-methylene-1,3-dioxolan-2-one, and , 4-diethyl-5-methylene-1,3-dioxolan-2-one, and the like.
  • the methylene carbonate compound a compound having only one methylene group is exemplified, but the methylene carbonate compound may have two or more methylene groups.
  • a cyclic carbonate containing an unsaturated carbon bond does not fall under either a fluorinated cyclic carbonate or a cyanated cyclic carbonate, but falls under an unsaturated cyclic carbonate.
  • a fluorinated cyclic carbonate ester is a cyclic carbonate ester containing fluorine as a constituent element.
  • the number of fluorine atoms is not particularly limited, and may be one or two or more. That is, the fluorinated cyclic carbonate is a compound in which one or more hydrogen atoms in the cyclic carbonate are replaced with fluorine.
  • fluorinated cyclic carbonate esters include ethylene fluorocarbonate (4-fluoro-1,3-dioxolan-2-one) and ethylene difluorocarbonate (4,5-difluoro-1,3-dioxolan-2-one). It is.
  • a cyclic carbonate containing fluorine as a constituent element does not fall under either an unsaturated cyclic carbonate or a cyanated cyclic carbonate, but falls under a fluorinated cyclic carbonate.
  • the cyanated cyclic carbonate ester is a cyclic carbonate ester containing a cyano group.
  • the number of cyano groups is not particularly limited, and may be one or two or more. That is, the cyanated cyclic carbonate is a compound in which one or more hydrogen atoms in the cyclic carbonate are substituted with a cyano group.
  • cyanated cyclic carbonate esters include cyanoethylene carbonate (4-cyano-1,3-dioxolan-2-one) and dicyanoethylene carbonate (4,5-dicyano-1,3-dioxolan-2-one). It is.
  • a cyano group-containing cyclic carbonate does not fall under either an unsaturated cyclic carbonate or a fluorinated cyclic carbonate, but falls under a cyanated cyclic carbonate.
  • the additive contains one or more of the following: sulfonic acid ester, sulfuric acid ester, sulfite ester, dicarboxylic anhydride, disulfonic acid anhydride, sulfonic acid carboxylic acid anhydride and sulfobenzoic acid imide.
  • sulfonic acid ester sulfuric acid ester, sulfite ester, dicarboxylic anhydride, disulfonic acid anhydride, sulfonic acid carboxylic acid anhydride, and sulfobenzoic acid imide.
  • sulfonic acid ester sulfuric acid ester, sulfite ester, dicarboxylic anhydride, disulfonic acid anhydride, sulfonic acid carboxylic acid anhydride, and sulfobenzoic acid imide.
  • sulfonic acid esters include 1,3-propane sultone, 1-propene-1,3-sultone, 1,4-butane sultone, 2,4-butane sultone, and methanesulfonic acid propargyl ester.
  • sulfuric esters include 1,3,2-dioxathiolane 2,2-dioxide, 1,3,2-dioxathiane 2,2-dioxide, 4-methylsulfonyloxymethyl-2,2-dioxo-1,3, 2-dioxathiolane and the like.
  • sulfite esters include 1,3-propane sultone, 1-propene-1,3-sultone, 1,4-butane sultone, 2,4-butane sultone, and methanesulfonic acid propargyl ester.
  • sulfite esters include 1,3,2-dioxathiolane 2-oxide and 4-methyl-1,3,2-dioxathiolane 2-oxide.
  • dicarboxylic anhydrides include 1,4-dioxane-2,6-dione, succinic anhydride, and glutaric anhydride.
  • disulfonic anhydride examples include 1,2-ethanedisulfonic anhydride, 1,3-propanedidisulfonic anhydride, and hexafluoro-1,3-propanedisulfonic anhydride.
  • sulfonic acid carboxylic acid anhydrides include 2-sulfobenzoic anhydride and 2,2-dioxoxothiolan-5-one.
  • sulfobenzoic acid imide examples include o-sulfobenzimide and N-methylsaccharin.
  • the additive contains any one type or two or more types of nitrile compounds. This is because the electrochemical stability of the electrolytic solution is improved. This further suppresses the decomposition reaction of the electrolytic solution during charging and discharging, thereby further suppressing the decrease in discharge capacity even if charging and discharging are repeated. In this case, the generation of gas caused by the decomposition reaction of the electrolytic solution is also suppressed.
  • This nitrile compound is a compound containing one or more cyano groups (-CN).
  • nitrile compounds include octanenitrile, benzonitrile, phthalonitrile, succinonitrile, glutaronitrile, adiponitrile, sebaconitrile, 1,3,6-hexanetricarbonitrile, 3,3'-oxydipropionitrile, 3 -Butoxypropionitrile, ethylene glycol bispropionitrile ether, 1,2,2,3-tetracyanopropane, tetracyanopropane, fumaronitrile, 7,7,8,8-tetracyanoquinodimethane, cyclopentanecarbonitrile , 1,3,5-cyclohexanetricarbonitrile and 1,3-bis(dicyanomethylidene)indane.
  • the electrolyte includes a triple bond compound and a fluorophosphate.
  • the triple bond compound includes one or both of a first triple bond compound and a second triple bond compound, and the fluorophosphate is one of the first fluorophosphate and the second fluorophosphate. Contains one or both of the following.
  • fluorophosphate can also be used as an electrolyte salt when the secondary battery is a lithium ion secondary battery. It works well, so you can get better results.
  • the content of the triple bond compound in the electrolytic solution is 0.01% to 5% by weight, the electrochemical durability of the film formed on the surface of the negative electrode 22 will be sufficiently improved, resulting in higher effects. can be obtained.
  • the content of fluorophosphate in the electrolytic solution is 0.01% to 2% by weight, the electrochemical durability of the film formed on the surface of the negative electrode 22 is sufficiently improved. effect can be obtained.
  • the electrolytic solution contains one or more of the following: unsaturated cyclic carbonate, fluorinated cyclic carbonate, and cyanated cyclic carbonate, the decomposition reaction of the electrolyte will be further suppressed. , higher effects can be obtained.
  • the electrolytic solution contains one or more of the following: sulfonic acid ester, sulfuric acid ester, sulfite ester, dicarboxylic acid anhydride, disulfonic acid anhydride, sulfonic acid carboxylic acid anhydride, and sulfobenzoic acid imide. If there is, the decomposition reaction of the electrolytic solution will be further suppressed, and higher effects can be obtained.
  • the secondary battery described here is a secondary battery whose battery capacity is obtained by utilizing intercalation and desorption of electrode reactants, and includes an electrolytic solution along with a positive electrode and a negative electrode.
  • the charging capacity of the negative electrode is larger than the discharging capacity of the positive electrode. That is, the electrochemical capacity per unit area of the negative electrode is set to be larger than the electrochemical capacity per unit area of the positive electrode. This is to prevent electrode reactants from depositing on the surface of the negative electrode during charging.
  • the type of electrode reactant is not particularly limited, but specifically light metals such as alkali metals and alkaline earth metals.
  • Alkali metals include lithium, sodium and potassium
  • alkaline earth metals include beryllium, magnesium and calcium.
  • a secondary battery whose battery capacity is obtained by utilizing intercalation and desorption of lithium is a so-called lithium ion secondary battery.
  • lithium ion secondary battery lithium is intercalated and released in an ionic state.
  • Configuration> 1 shows a cross-sectional structure of a secondary battery
  • FIG. 2 shows a cross-sectional structure of a battery element 20 shown in FIG.
  • this secondary battery mainly includes a battery can 11, a pair of insulating plates 12 and 13, a battery element 20, a positive electrode lead 25, and a negative electrode lead 26. ing.
  • the secondary battery described here is a cylindrical secondary battery in which a battery element 20 is housed inside a cylindrical battery can 11 .
  • the battery can 11 is a storage member that stores the battery element 20 and the like. This battery can 11 has one open end and the other closed end, so it has a hollow structure. Further, the battery can 11 includes one or more metal materials such as iron, aluminum, iron alloy, and aluminum alloy. Note that the surface of the battery can 11 may be plated with a metal material such as nickel.
  • a battery lid 14 , a safety valve mechanism 15 , and a heat sensitive resistance element (PTC element) 16 are crimped to one open end of the battery can 11 via a gasket 17 .
  • the battery can 11 is sealed by the battery lid 14.
  • the battery lid 14 includes the same material as the material from which the battery can 11 is formed.
  • Each of the safety valve mechanism 15 and the PTC element 16 is provided inside the battery lid 14, and the safety valve mechanism 15 is electrically connected to the battery lid 14 via the PTC element 16.
  • the gasket 17 includes an insulating material, and the surface of the gasket 17 may be coated with asphalt or the like.
  • the insulating plates 12 and 13 are arranged to face each other with the battery element 20 in between. Thereby, the battery element 20 is sandwiched between the insulating plates 12 and 13.
  • the battery element 20 is a power generating element that includes a positive electrode 21, a negative electrode 22, a separator 23, and an electrolyte (not shown).
  • This battery element 20 is a so-called wound electrode body. That is, the positive electrode 21 and the negative electrode 22 are stacked on each other with the separator 23 in between, and are wound so as to face each other with the separator 23 in between.
  • a center pin 24 is inserted into a winding center space 20S provided at the winding center of the battery element 20. However, the center pin 24 may be omitted.
  • the positive electrode 21 includes a positive electrode current collector 21A and a positive electrode active material layer 21B.
  • the positive electrode current collector 21A has a pair of surfaces on which the positive electrode active material layer 21B is provided.
  • the positive electrode current collector 21A includes a conductive material such as a metal material, and a specific example of the conductive material is aluminum.
  • the positive electrode active material layer 21B includes one or more types of positive electrode active materials capable of intercalating and deintercalating lithium. However, the positive electrode active material layer 21B may further contain one or more of other materials such as a positive electrode binder and a positive electrode conductive agent.
  • the method for forming the positive electrode active material layer 21B is not particularly limited, and specifically, a coating method or the like is used.
  • the positive electrode 21 since the positive electrode active material layers 21B are provided on both sides of the positive electrode current collector 21A, the positive electrode 21 includes two positive electrode active material layers 21B. However, since the positive electrode active material layer 21B is provided only on one side of the positive electrode current collector 21A on the side where the positive electrode 21 faces the negative electrode 22, the positive electrode 21 only has one positive electrode active material layer 21B. May contain.
  • the type of positive electrode active material is not particularly limited, but specifically includes a lithium-containing compound.
  • This lithium-containing compound is a compound containing lithium and one or more transition metal elements as constituent elements, and may further contain one or more other elements as constituent elements.
  • the type of other element is not particularly limited as long as it is an element other than lithium and transition metal elements, but specifically, it is an element belonging to Groups 2 to 15 in the long period periodic table.
  • the type of lithium-containing compound is not particularly limited, but specifically includes oxides, phosphoric acid compounds, silicic acid compounds, and boric acid compounds.
  • oxides include LiNiO 2 , LiCoO 2 , LiCo 0.98 Al 0.01 Mg 0.01 O 2 , LiNi 0.5 Co 0.2 Mn 0.3 O 2 and LiMn 2 O 4 .
  • phosphoric acid compounds include LiFePO 4 , LiMnPO 4 and LiFe 0.5 Mn 0.5 PO 4 .
  • the positive electrode binder contains one or more of materials such as synthetic rubber and polymer compounds.
  • synthetic rubber include styrene butadiene rubber, fluorine rubber, and ethylene propylene diene.
  • polymer compound include polyvinylidene fluoride, polyimide, and carboxymethyl cellulose.
  • the positive electrode conductive agent contains one or more types of conductive materials such as carbon materials, and specific examples of the carbon materials include graphite, carbon black, acetylene black, and Ketjen black. .
  • the conductive material may be a metal material, a polymer compound, or the like.
  • the negative electrode 22 includes a negative electrode current collector 22A and a negative electrode active material layer 22B.
  • the negative electrode current collector 22A has a pair of surfaces on which the negative electrode active material layer 22B is provided.
  • This negative electrode current collector 22A includes a conductive material such as a metal material, and a specific example of the conductive material is copper.
  • the negative electrode active material layer 22B includes one or more types of negative electrode active materials capable of intercalating and deintercalating lithium. However, the negative electrode active material layer 22B may further contain one or more of other materials such as a negative electrode binder and a negative electrode conductive agent.
  • the method for forming the negative electrode active material layer 22B is not particularly limited, but specifically, any one of a coating method, a gas phase method, a liquid phase method, a thermal spraying method, a firing method (sintering method), etc. There are two or more types.
  • the negative electrode 22 since the negative electrode active material layers 22B are provided on both sides of the negative electrode current collector 22A, the negative electrode 22 includes two negative electrode active material layers 22B. However, since the negative electrode active material layer 22B is provided only on one side of the negative electrode current collector 22A on the side where the negative electrode 22 faces the positive electrode 21, the negative electrode 22 only has one negative electrode active material layer 22B. May contain.
  • the type of negative electrode active material is not particularly limited, but specifically includes carbon materials and metal-based materials. This is because high energy density can be obtained.
  • carbon materials include easily graphitizable carbon, non-graphitizable carbon, and graphite (natural graphite and artificial graphite).
  • a metal-based material is a material containing as a constituent element one or more of metal elements and metalloid elements that can form an alloy with lithium.
  • the metal elements and metalloid elements are: , silicon and tin.
  • This metallic material may be a single substance, an alloy, a compound, a mixture of two or more types thereof, or a material containing phases of two or more types thereof.
  • Specific examples of metal-based materials include TiSi 2 and SiO x (0 ⁇ x ⁇ 2, or 0.2 ⁇ x ⁇ 1.4).
  • the details regarding the negative electrode binder are the same as the details regarding the positive electrode binder, and the details regarding the negative electrode conductive agent are the same as the details regarding the positive electrode conductive agent.
  • the separator 23 is an insulating porous film interposed between the positive electrode 21 and the negative electrode 22, and prevents contact (short circuit) between the positive electrode 21 and negative electrode 22. Allows lithium ions to pass through.
  • This separator 23 contains a high molecular compound such as polyethylene.
  • electrolytic solution is impregnated into each of the positive electrode 21, the negative electrode 22, and the separator 23, and has the above-described configuration. That is, the electrolyte contains a triple bond compound and a fluorophosphate.
  • the positive electrode lead 25 is connected to the positive electrode current collector 21A of the positive electrode 21, and includes a conductive material such as aluminum. This positive electrode lead 25 is electrically connected to the battery lid 14 via the safety valve mechanism 15.
  • the negative electrode lead 26 is connected to the negative electrode current collector 22A of the negative electrode 22, and contains a conductive material such as nickel. This negative electrode lead 26 is electrically connected to the battery can 11.
  • the secondary battery operates as follows.
  • lithium is released from the positive electrode 21, and at the same time, the lithium is inserted into the negative electrode 22 via the electrolyte.
  • lithium is released from the negative electrode 22, and at the same time, the lithium is inserted into the positive electrode 21 via the electrolyte.
  • lithium is intercalated and released in an ionic state.
  • a positive electrode 21 and a negative electrode 22 are prepared and an electrolytic solution is prepared according to an example procedure described below. As well as assembling the battery, the secondary battery after assembly is stabilized. Note that the procedure for preparing the electrolytic solution is as described above.
  • a cathode active material, a cathode binder, and a cathode conductive agent are mixed together to form a cathode mixture.
  • the cathode mixture is added to a solvent to form a paste-like cathode mixture slurry.
  • This solvent may be an aqueous solvent or an organic solvent.
  • a positive electrode active material layer 21B is formed by applying a positive electrode mixture slurry to both surfaces of the positive electrode current collector 21A.
  • the positive electrode active material layer 21B may be compression molded using a roll press machine or the like.
  • the positive electrode active material layer 21B may be heated, or compression molding may be repeated multiple times. Thereby, the positive electrode active material layers 21B are formed on both sides of the positive electrode current collector 21A, so that the positive electrode 21 is manufactured.
  • the negative electrode 22 is formed by the same procedure as the positive electrode 21 described above. Specifically, first, a paste-like negative electrode mixture slurry is prepared by adding a mixture (negative electrode mixture) in which a negative electrode active material, a negative electrode binder, and a negative electrode conductive agent are mixed together into a solvent. Subsequently, a negative electrode active material layer 22B is formed by applying a negative electrode mixture slurry to both surfaces of the negative electrode current collector 22A. After this, the negative electrode active material layer 22B may be compression molded. Thereby, the negative electrode active material layers 22B are formed on both sides of the negative electrode current collector 22A, so that the negative electrode 22 is manufactured.
  • a paste-like negative electrode mixture slurry is prepared by adding a mixture (negative electrode mixture) in which a negative electrode active material, a negative electrode binder, and a negative electrode conductive agent are mixed together into a solvent.
  • a negative electrode active material layer 22B is formed by applying a negative electrode mixture slurry to both surfaces of the negative
  • the positive electrode lead 25 is connected to the positive electrode current collector 21A of the positive electrode 21 using a joining method such as welding, and the negative electrode lead 25 is connected to the negative electrode current collector 22A of the negative electrode 22 using a joining method such as welding. Connect the lead 26.
  • the positive electrode 21 and the negative electrode 22 are laminated with each other via the separator 23, and then the positive electrode 21, the negative electrode 22, and the separator 23 are wound to form a wound body (not shown) having a winding center space 20S. ).
  • This wound body has a configuration similar to that of the battery element 20, except that the positive electrode 21, the negative electrode 22, and the separator 23 are not impregnated with an electrolytic solution.
  • the center pin 24 is inserted into the winding center space 20S of the wound body.
  • the wound body and the insulating plates 12 and 13 are stored inside the battery can 11 in a state where the wound body is sandwiched between the insulating plates 12 and 13.
  • the positive electrode lead 25 is connected to the safety valve mechanism 15 using a joining method such as welding
  • the negative electrode lead 26 is connected to the battery can 11 using a joining method such as welding.
  • the wound body is impregnated with the electrolytic solution.
  • the positive electrode 21, the negative electrode 22, and the separator 23 are each impregnated with the electrolytic solution, so that the battery element 20 is manufactured.
  • the battery can 11 is crimped via the gasket 17. Thereby, the battery lid 14, safety valve mechanism 15, and PTC element 16 are fixed to the battery can 11, and the battery element 20 is sealed inside the battery can 11, so that a secondary battery is assembled.
  • the secondary battery includes an electrolytic solution, and the electrolytic solution has the above-described configuration.
  • the decomposition reaction of the electrolytic solution on the surface of the negative electrode 22 is suppressed, so that a decrease in discharge capacity is suppressed. Therefore, excellent battery characteristics can be obtained.
  • the secondary battery is a lithium ion secondary battery
  • a sufficient battery capacity can be stably obtained by utilizing intercalation and desorption of lithium, so higher effects can be obtained.
  • FIG. 3 shows a cross-sectional configuration of a secondary battery in Modification Example 1, and more specifically, it schematically shows an enlarged cross-sectional configuration of a negative electrode active material 220 included in a negative electrode 22.
  • the secondary battery described here has the same configuration as the secondary battery described above, except that it includes the negative electrode active material 220.
  • the negative electrode active material layer 22B includes a plurality of particulate negative electrode active materials (negative electrode active material 220). Contains. However, in FIG. 3, only one negative electrode active material 220 is shown.
  • the center portion 221 includes one or more types of materials capable of intercalating and deintercalating lithium, and the materials include the above-described carbon materials and metal-based materials.
  • the covering portion 222 covers the surface of the center portion 221.
  • the covering portion 222 may cover the entire surface of the center portion 221, or may cover only a portion of the surface of the center portion 221. In the latter case, a plurality of covering portions 222 may cover the surface of the center portion 221 at a plurality of locations separated from each other.
  • This covering portion 222 is formed by performing stabilization treatment (initial charging/discharging) on the assembled secondary battery during the manufacturing process of the secondary battery.
  • stabilization treatment initial charging/discharging
  • the covering portion 222 is formed to cover the surface of the central portion 221 having reactivity
  • the reactivity of the surface of the central portion 221 is reduced using the covering portion 222.
  • the coating portion 222 is formed on the surface of the center portion 221, but also a coating may be formed on the surface of the positive electrode active material. This is because the decomposition reaction of the electrolyte on the surface of the positive electrode active material is also suppressed.
  • the covering portion 222 contains nickel as a constituent element.
  • the state of nickel in the covering portion 222 is not particularly limited, and may be a single substance, a compound, an alloy, or two or more of these types.
  • the reason why the covering part 222 contains nickel as a constituent element is that the physical strength of the covering part 222 is improved, so that the covering part 222 is easily maintained even after repeated charging and discharging. This further suppresses the decomposition reaction of the electrolytic solution, thereby further suppressing the decrease in discharge capacity even if charging and discharging are repeated.
  • the method for making the coating portion 222 contain nickel as a constituent element, or in other words, the source of nickel, is not particularly limited.
  • the positive electrode active material layer 21B may further contain nickel powder.
  • This nickel powder is so-called powdered nickel.
  • the content of nickel powder in the positive electrode active material layer 21B is not particularly limited and can be set arbitrarily.
  • the positive electrode 21 is produced by the same procedure except that nickel powder is further added to the positive electrode mixture.
  • the electrolytic solution may further contain any one type or two or more types of nickel compounds.
  • This nickel is a compound containing nickel as a constituent element.
  • the type of nickel compound is not particularly limited, but specific examples include nickel acetate.
  • the content of the nickel compound in the electrolytic solution is not particularly limited and can be set arbitrarily.
  • the electrolytic solution is prepared by the same procedure except that a nickel compound is further added to the solvent.
  • both the positive electrode 21 and the electrolytic solution may be used as the nickel supply source.
  • the covering portion 222 contains nickel as a constituent element, the physical strength of the covering portion 222 is further improved. Thereby, even if charging and discharging are repeated, the decomposition reaction of the electrolytic solution is further suppressed, and therefore the decrease in discharge capacity is further suppressed. Therefore, higher effects can be obtained.
  • the type of battery structure is not particularly limited, and may be a laminate film type, a square type, a coin type, a button type, or the like.
  • a separator 23 which is a porous membrane, was used. However, although not specifically illustrated here, a laminated separator including a polymer compound layer may also be used.
  • the laminated separator includes a porous membrane having a pair of surfaces and a polymer compound layer provided on one or both sides of the porous membrane. This is because the adhesion of the separator to each of the positive electrode 21 and the negative electrode 22 is improved, so that misalignment (misalignment) of the battery element 20 is suppressed. As a result, even if a decomposition reaction of the electrolyte occurs, swelling of the secondary battery is suppressed.
  • the polymer compound layer contains a polymer compound such as polyvinylidene fluoride. This is because polyvinylidene fluoride and the like have excellent physical strength and are electrochemically stable.
  • one or both of the porous membrane and the polymer compound layer may contain any one type or two or more types of the plurality of insulating particles. This is because the plurality of insulating particles promote heat dissipation when the secondary battery generates heat, thereby improving the safety (heat resistance) of the secondary battery.
  • the insulating particles contain one or both of an inorganic material and a resin material. Specific examples of inorganic materials include aluminum oxide, aluminum nitride, boehmite, silicon oxide, titanium oxide, magnesium oxide, and zirconium oxide. Specific examples of the resin material include acrylic resin and styrene resin.
  • a precursor solution containing a polymer compound, a solvent, etc. is prepared, and then the precursor solution is applied to one or both sides of the porous membrane.
  • a plurality of insulating particles may be added to the precursor solution, if necessary.
  • a positive electrode 21 and a negative electrode 22 are stacked on each other with a separator 23 and an electrolyte layer in between, and the positive electrode 21, negative electrode 22, separator 23, and electrolyte layer are wound.
  • This electrolyte layer is interposed between the positive electrode 21 and the separator 23 and also between the negative electrode 22 and the separator 23.
  • the electrolyte layer contains an electrolyte and a polymer compound, and the electrolyte is retained by the polymer compound. This is because electrolyte leakage is prevented.
  • the structure of the electrolytic solution is as described above.
  • the polymer compound includes polyvinylidene fluoride and the like.
  • a secondary battery used as a power source may be a main power source or an auxiliary power source in electronic devices, electric vehicles, and the like.
  • the main power source is a power source that is used preferentially, regardless of the presence or absence of other power sources.
  • the auxiliary power source may be a power source used in place of the main power source, or a power source that can be switched from the main power source.
  • secondary batteries are as follows. Electronic devices such as video cameras, digital still cameras, mobile phones, notebook computers, headphone stereos, portable radios, and portable information terminals. Backup power supplies and storage devices such as memory cards. Power tools such as power drills and power saws. This is a battery pack installed in electronic devices. Medical electronic devices such as pacemakers and hearing aids. Electric vehicles such as electric vehicles (including hybrid vehicles). A power storage system such as a household or industrial battery system that stores power in case of an emergency. In these applications, one secondary battery or a plurality of secondary batteries may be used.
  • the battery pack may use single cells or assembled batteries.
  • An electric vehicle is a vehicle that operates (travels) using a secondary battery as a driving power source, and may be a hybrid vehicle that also includes a driving source other than the secondary battery.
  • household electrical appliances and the like can be used by using the electric power stored in a secondary battery, which is a power storage source.
  • FIG. 4 shows the block configuration of the battery pack.
  • the battery pack described here is a battery pack (so-called soft pack) using one secondary battery, and is installed in electronic devices such as smartphones.
  • this battery pack includes a power source 51 and a circuit board 52.
  • This circuit board 52 is connected to a power source 51 and includes a positive terminal 53, a negative terminal 54, and a temperature detection terminal 55.
  • the power source 51 includes one secondary battery.
  • the positive electrode lead is connected to the positive electrode terminal 53
  • the negative electrode lead is connected to the negative electrode terminal 54.
  • This power source 51 can be connected to the outside via the positive terminal 53 and the negative terminal 54, and therefore can be charged and discharged.
  • the circuit board 52 includes a control section 56, a switch 57, a PTC element 58, and a temperature detection section 59. However, the PTC element 58 may be omitted.
  • the control unit 56 includes a central processing unit (CPU), memory, etc., and controls the operation of the entire battery pack. This control unit 56 detects and controls the usage status of the power source 51 as necessary.
  • CPU central processing unit
  • memory etc.
  • the control unit 56 prevents the charging current from flowing through the current path of the power source 51 by cutting off the switch 57. Make it.
  • the overcharge detection voltage is not particularly limited, specifically, it is 4.20V ⁇ 0.05V
  • the overdischarge detection voltage is not particularly limited, but specifically, it is 2.40V ⁇ 0.1V. It is.
  • the switch 57 includes a charging control switch, a discharging control switch, a charging diode, a discharging diode, and the like, and switches whether or not the power supply 51 is connected to an external device according to an instruction from the control unit 56.
  • This switch 57 includes a field effect transistor (MOSFET) using a metal oxide semiconductor, and the charging/discharging current is detected based on the ON resistance of the switch 57.
  • MOSFET field effect transistor
  • the temperature detection section 59 includes a temperature detection element such as a thermistor.
  • the temperature detection section 59 measures the temperature of the power supply 51 using the temperature detection terminal 55 and outputs the temperature measurement result to the control section 56 .
  • the temperature measurement result measured by the temperature detection unit 59 is used when the control unit 56 performs charging/discharging control during abnormal heat generation and when the control unit 56 performs correction processing when calculating the remaining capacity.
  • a positive electrode active material lithium cobalt oxide (LiCoO 2 ), which is a lithium-containing compound (oxide)
  • a positive electrode binder polyvinylidene fluoride
  • a positive electrode conductive agent graphite
  • a positive electrode mixture slurry is applied to both sides of the positive electrode current collector 21A (a strip-shaped aluminum foil having a thickness of 12 ⁇ m) using a coating device, and then the positive electrode mixture slurry is dried to form a positive electrode active material.
  • a material layer 21B was formed.
  • the positive electrode active material layer 21B was compression molded using a roll press machine. In this way, the positive electrode 21 was manufactured.
  • a coating device is used to apply a negative electrode mixture slurry to both sides of the negative electrode current collector 22A (a strip-shaped copper foil with a thickness of 15 ⁇ m), and then the negative electrode mixture slurry is dried to form a negative electrode active material.
  • a material layer 22B was formed.
  • the negative electrode active material layer 22B was compression molded using a roll press machine. In this way, the negative electrode 22 was manufactured.
  • methyl 2-octoate OCM
  • methyl 2-nonynoate NM
  • methyl 2-hexanoate HXM
  • methyl 2-heptate HPM
  • PNE ethyl 2-pentate
  • BTE ethyl 2-butyrate
  • DCM methyl 2-decanoate
  • BTDI Diisopropyl 2-butyric acid diacid
  • lithium difluorophosphate (DFPL) and sodium difluorophosphate (DFPN) were used as the first fluorophosphate.
  • Dilithium monofluorophosphate (MFPL) was used as the second fluorophosphate.
  • electrolytic solutions were prepared using the same procedure except that one or both of the triple bond compound and fluorophosphoric acid were not used.
  • the positive electrode lead 25 (aluminum foil) was welded to the positive electrode current collector 21A of the positive electrode 21, and the negative electrode lead 26 (copper foil) was welded to the negative electrode current collector 22A of the negative electrode 22.
  • the positive electrode 21 and the negative electrode 22 are laminated with each other via the separator 23 (a microporous polyethylene film having a thickness of 15 ⁇ m), and then the positive electrode 21, the negative electrode 22, and the separator 23 are wound.
  • a wound body having a rotation center space 20S was produced.
  • the center pin 24 was inserted into the winding center space 20S of the wound body.
  • the insulating plates 12 and 13 were housed inside the battery can 11 together with the wound body.
  • the positive electrode lead 25 was welded to the safety valve mechanism 15, and the negative electrode lead 26 was welded to the battery can 11.
  • an electrolytic solution was injected into the inside of the battery can 11.
  • the wound body was impregnated with the electrolytic solution, so that the battery element 20 was manufactured.
  • the battery can 11 was crimped with the gasket 17 interposed therebetween. As a result, the battery can 11 was sealed, and the secondary battery was assembled.
  • constant current charging was performed with a current of 0.1C until the voltage reached 4.2V, and then constant voltage charging was performed with the voltage of 4.2V until the current reached 0.05C.
  • constant current discharge was performed at a current of 0.1C until the voltage reached 3.0V.
  • 0.1C is a current value that completely discharges the battery capacity (theoretical capacity) in 10 hours
  • 0.05C is a current value that completely discharges the battery capacity in 20 hours. With this, the secondary battery was completed.
  • constant current charging was performed with a current of 1C until the voltage reached 4.2V, and then constant voltage charging was performed with the voltage of 4.2V until the current reached 0.05C.
  • 1C is a current value that completely discharges the battery capacity in one hour.
  • the discharge capacity (first cycle discharge capacity) was measured by discharging the secondary battery in the same environment. During discharging, constant current discharge was performed at a current of 3C until the voltage reached 3.0V. 3C is a current value that completely discharges the battery capacity in 1/3 hour.
  • discharge capacity at the 100th cycle was measured by repeatedly charging and discharging the secondary battery in the same environment until the number of cycles reached 100 cycles.
  • the charging and discharging conditions for the second and subsequent cycles were the same as those for the first cycle.
  • capacity retention rate (%) (discharge capacity at 100th cycle/discharge capacity at 1st cycle) x 100. .
  • Examples 19 to 24 As shown in Table 3, the same procedure as in Example 3 was used except that the electrolytic solution contained an additive (unsaturated cyclic carbonate, fluorinated cyclic carbonate, or cyanated cyclic carbonate). After producing the next battery, battery characteristics were evaluated. The classification, type, and content (% by weight) of the additives are shown in Table 3.
  • vinylene carbonate (VC) was used as the unsaturated cyclic carbonate.
  • Fluoroethylene carbonate (FEC) was used as the fluorinated cyclic carbonate.
  • cyanated cyclic carbonate ester cyanoethylene carbonate (CEC) was used.
  • Examples 25 to 44> As shown in Tables 4 and 5, additives (sulfonate, sulfate, sulfite, dicarboxylic anhydride, disulfonic anhydride, sulfonic carboxylic anhydride, or sulfobenzoic acid imide) were added to the electrolyte.
  • a secondary battery was produced by the same procedure as in Example 3 except that it was included, and then the battery characteristics were evaluated.
  • the classification, type, and content (% by weight) of the additives are as shown in Tables 4 and 5.
  • the sulfonic acid esters include 1,3-propane sultone (PS), 1-propene-1,3-sultone (PRS), 1,4-butane sultone (BS1), and 2,4-butane sultone (BS2). and methanesulfonic acid propargyl ester (MSP).
  • PS 1,3-propane sultone
  • PRS 1-propene-1,3-sultone
  • BS1 1,4-butane sultone
  • BS2 2,4-butane sultone
  • MSP methanesulfonic acid propargyl ester
  • 1,3,2-dioxathiolane 2,2-dioxide (OTO), 1,3,2-dioxathiane 2,2-dioxide (OTA) and 4-methylsulfonyloxymethyl-2,2-dioxo-1 , 3,2-dioxathiolane (SOTO) was used.
  • DTO 1,3,2-dioxathiolane 2-oxide
  • MDTO 4-methyl-1,3,2-dioxathiolane 2-oxide
  • DOD 1,4-dioxane-2,6-dione
  • SA succinic anhydride
  • GA glutaric anhydride
  • ESA 1,2-ethanedisulfonic anhydride
  • PSA 1,3-propanedidisulfonic anhydride
  • FPSA hexafluoro1,3-propanedisulfonic anhydride
  • SBA 2-sulfobenzoic anhydride
  • DOTO 2,2-dioxoxathiolan-5-one
  • the electrolyte contains additives (sulfonic acid ester, sulfate ester, sulfite ester, dicarboxylic acid anhydride, disulfonic acid anhydride, sulfonic acid carboxylic acid anhydride, or sulfobenzoic acid imide).
  • additives sulfonic acid ester, sulfate ester, sulfite ester, dicarboxylic acid anhydride, disulfonic acid anhydride, sulfonic acid carboxylic acid anhydride, or sulfobenzoic acid imide.
  • Example 45, 46> As shown in Table 6, a secondary battery was prepared by the same procedure as in Example 3 except that the negative electrode active material 220 (center portion 221 and covering portion 222) was used as the negative electrode active material, and then the battery Characteristics were evaluated.
  • nickel compound nickel acetate tetrahydrate
  • An electrolytic solution was prepared according to the procedure. In this case, the content of the nickel compound in the electrolyte was 1% by weight.
  • the same procedure was used except that the center portion 221 (artificial graphite) was used instead of the negative electrode active material (artificial graphite).
  • the negative electrode active material 220 including the center portion 221 and the covering portion 222 was formed, the negative electrode 22 including the negative electrode active material 220 was manufactured.
  • the negative electrode active material 220 is collected by disassembling the secondary battery, and then a scanning electron microscope (scanning electron microscope SU3800/SU3900 manufactured by Hi-Tech Co., Ltd.), an energy dispersive type Table 6 shows the results of analyzing the negative electrode active material 220 using an X-ray spectrometer (EDS) and an X-ray photoelectron spectrometer (EDX).
  • a scanning electron microscope scanning electron microscope SU3800/SU3900 manufactured by Hi-Tech Co., Ltd.
  • an energy dispersive type Table 6 shows the results of analyzing the negative electrode active material 220 using an X-ray spectrometer (EDS) and an X-ray photoelectron spectrometer (EDX).
  • the element structure of the battery element is a wound type.
  • the element structure of the battery element is not particularly limited, other element structures such as a stacked type and a 99-fold type may be used.
  • positive electrodes and negative electrodes are alternately stacked with separators in between, and in the 99-fold type, positive electrodes and negative electrodes are folded in a zigzag pattern while facing each other with separators in between.
  • the electrode reactant is not particularly limited.
  • the electrode reactants may be other alkali metals such as sodium and potassium, or alkaline earth metals such as beryllium, magnesium, and calcium, as described above.
  • the electrode reactant may be other light metals such as aluminum.
  • the present technology can also have the following configuration. ⁇ 1> a positive electrode; a negative electrode; an electrolyte containing a triple bond compound and a fluorophosphate;
  • the triple bond compound includes at least one of a compound represented by formula (1) and a compound represented by formula (2),
  • the fluorophosphate salt contains at least one of a compound represented by formula (3) and a compound represented by formula (4), Secondary battery.
  • each of R1 to R4 is an alkyl group.
  • M1PF2O2 ...( 3 ) M1 is an alkali metal element.
  • M2 2 PFO 3 ...(4) M2 is an alkali metal element.
  • ⁇ 2> The number of carbon atoms in the alkyl group is 1 or more and 7 or less,
  • ⁇ 3> the alkali metal element is lithium
  • ⁇ 4> The content of the triple bond compound in the electrolytic solution is 0.01% by weight or more and 5% by weight or less, The secondary battery according to any one of ⁇ 1> to ⁇ 3>.
  • the content of the fluorophosphate in the electrolytic solution is 0.01% by weight or more and 2% by weight or less, The secondary battery according to any one of ⁇ 1> to ⁇ 4>.
  • the electrolytic solution further contains at least one of an unsaturated cyclic carbonate, a fluorinated cyclic carbonate, and a cyanated cyclic carbonate.
  • the electrolytic solution further contains at least one of a sulfonic acid ester, a sulfuric acid ester, a sulfite ester, a dicarboxylic anhydride, a disulfonic acid anhydride, a sulfonic acid carboxylic acid anhydride, and a sulfobenzoic acid imide.
  • the secondary battery according to any one of ⁇ 1> to ⁇ 6>.
  • the negative electrode includes a negative electrode active material, The negative electrode active material is A central part that absorbs and releases electrode reactants; a covering part that covers the surface of the central part and contains nickel as a constituent element; The secondary battery according to any one of ⁇ 1> to ⁇ 7>.
  • a lithium ion secondary battery The secondary battery according to any one of ⁇ 1> to ⁇ 8>.
  • ⁇ 10> including triple bond compounds and fluorophosphates,
  • the triple bond compound includes at least one of a compound represented by formula (1) and a compound represented by formula (2),
  • the fluorophosphate salt contains at least one of a compound represented by formula (3) and a compound represented by formula (4), Electrolyte for secondary batteries.
  • Each of R1 to R4 is an alkyl group.
  • M1PF2O2 ...( 3 ) M1 is an alkali metal element.
  • M2 2 PFO 3 ...(4) M2 is an alkali metal element.

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WO2025227683A1 (zh) * 2024-04-30 2025-11-06 宁德时代新能源科技股份有限公司 圆柱电池单体、电池和用电装置

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WO2025227683A1 (zh) * 2024-04-30 2025-11-06 宁德时代新能源科技股份有限公司 圆柱电池单体、电池和用电装置

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