WO2025033413A1 - 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

Info

Publication number
WO2025033413A1
WO2025033413A1 PCT/JP2024/028024 JP2024028024W WO2025033413A1 WO 2025033413 A1 WO2025033413 A1 WO 2025033413A1 JP 2024028024 W JP2024028024 W JP 2024028024W WO 2025033413 A1 WO2025033413 A1 WO 2025033413A1
Authority
WO
WIPO (PCT)
Prior art keywords
secondary battery
electrolyte
negative electrode
positive electrode
compound
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/JP2024/028024
Other languages
English (en)
French (fr)
Japanese (ja)
Inventor
記功 山口
泰之 増田
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.)
Murata Manufacturing Co Ltd
Original Assignee
Murata Manufacturing Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Murata Manufacturing Co Ltd filed Critical Murata Manufacturing Co Ltd
Priority to JP2025539520A priority Critical patent/JPWO2025033413A1/ja
Publication of WO2025033413A1 publication Critical patent/WO2025033413A1/ja
Anticipated expiration legal-status Critical
Pending legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • 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
    • H01M10/056—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
    • 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 technology relates to electrolytes for secondary batteries and secondary batteries.
  • secondary batteries are being developed as a power source that is small, lightweight, and has a high energy density. These secondary batteries contain a positive electrode, a negative electrode, and an electrolyte, and various studies are being conducted on the configuration of these secondary batteries.
  • the non-aqueous electrolyte contains a fluorine-containing organic compound, and the content of the fluorine-containing organic compound in the non-aqueous electrolyte is 0.01% by weight to 20% by weight (see, for example, Patent Document 1).
  • the electrolyte contains dimethoxyethane and anisole, and the mixture ratio (molar ratio) of the dimethoxyethane and anisole is 1:2 (see, for example, Non-Patent Document 1).
  • the secondary battery electrolyte of one embodiment of the present technology contains an anisole compound represented by formula (1) and a non-aqueous solvent, and the molar ratio of the anisole compound to the non-aqueous solvent is 1.6 or more.
  • each of R1, R2, R3, R4, and R5 is either a hydrogen group, a halogen group, or a halogenated alkyl group. However, at least one of R1, R2, R3, R4, and R5 is either a halogen group or a halogenated alkyl group.
  • the secondary battery of one embodiment of the present technology includes a positive electrode, a negative electrode, and an electrolyte, and the electrolyte has a configuration similar to that of the electrolyte for the secondary battery of one embodiment of the present technology described above.
  • the secondary battery electrolyte contains an anisole compound and a non-aqueous solvent, and the molar ratio of the anisole compound to the non-aqueous solvent is 1.6 or more, so that excellent battery characteristics can be obtained.
  • FIG. 1 is a perspective view illustrating a configuration of a secondary battery according to an embodiment of the present technology.
  • FIG. 2 is an enlarged cross-sectional view showing the configuration of the battery element shown in FIG.
  • FIG. 3 is a block diagram showing a configuration of an application example of a secondary battery.
  • Electrolyte for secondary batteries First, an electrolyte for a secondary battery (hereinafter simply referred to as an "electrolyte”) according to an embodiment of the present technology will be described.
  • This electrolyte is a liquid electrolyte used in a secondary battery, which is an electrochemical device.
  • the electrolyte may also be used in other electrochemical devices.
  • the type of other electrochemical device is not particularly limited, but a specific example is a capacitor.
  • the electrolyte includes a solvent and an electrolyte salt.
  • solvent contains an anisole compound represented by formula (1) and a non-aqueous solvent. Since the non-aqueous solvent is defined separately from the anisole compound, the anisole compound is excluded from the non-aqueous solvent.
  • each of R1, R2, R3, R4, and R5 is either a hydrogen group, a halogen group, or a halogenated alkyl group. However, at least one of R1, R2, R3, R4, and R5 is either a halogen group or a halogenated alkyl group.
  • the anisole compound is a compound having an anisole-type skeleton as shown in formula (1).
  • the type of the anisole compound may be one type or two or more types.
  • each of R1 to R5 is not particularly limited as long as it is any of a hydrogen group, a halogen group, and a halogenated alkyl group.
  • the types of R1 to R5 may be the same as each other, or may be different from each other. Of course, any two or more types of R1 to R5 may be the same as each other.
  • R1 to R5 are either a halogen group or a halogenated alkyl group, so the anisole compound contains one or more halogens as a constituent element.
  • anisole a compound in which all of R1 to R5 are hydrogen groups, i.e., anisole, which is a compound that does not contain one or more halogens as a constituent element, is excluded from the anisole compounds described here.
  • this anisole compound does not contain one or more halogens as constituent elements in the methoxy group ( --OCH3 ), but contains one or more halogens as constituent elements in positions other than the methoxy group.
  • halogen group is not particularly limited, but specific examples include fluorine groups, chlorine groups, bromine groups, and iodine groups.
  • the halogen group contains one or both of a fluorine group and a chlorine group. As described below, this is because a good coating containing halogen derived from the anisole compound as a constituent element is easily formed on the surface of the negative electrode, and the decomposition reaction of the electrolyte on the surface of the negative electrode is sufficiently suppressed.
  • a halogenated alkyl group is an alkyl group in which one or more hydrogen groups have been replaced with a halogen group, and details regarding the halogen group are as described above.
  • the alkyl group may be linear or branched with one or more side chains.
  • alkyl groups include methyl, ethyl, propyl, butyl, pentyl, and hexyl groups.
  • alkyl groups may be linear or branched.
  • a propyl group may be an n-butyl group, a sec-butyl group, an isobutyl group, or a tert-butyl group.
  • the number of carbon atoms in the alkyl group is not particularly limited, but it is preferable that the number be 5 or less. This is because it improves the solubility and compatibility of the anisole compound.
  • anisole compounds include compounds represented by formulas (1-1) to (1-10).
  • the mixing ratio of the anisole compound to the non-aqueous solvent is regulated to be within a predetermined range. Details of the mixing ratio of the anisole compound to the non-aqueous solvent explained here will be described later.
  • the electrolyte is analyzed.
  • ICP inductively coupled plasma
  • NMR nuclear magnetic resonance spectroscopy
  • GC-MS gas chromatography-mass spectrometry
  • the secondary battery When using a secondary battery containing an electrolyte to analyze the electrolyte, the secondary battery is disassembled to recover the electrolyte, which is then analyzed. This allows the type of component (anisole compound) contained in the electrolyte to be identified.
  • Non-aqueous solvent The type of the non-aqueous solvent is not particularly limited as long as it is a so-called organic solvent.
  • the type of the non-aqueous solvent may be one type or two or more types. As described above, anisole compounds are excluded from the non-aqueous solvent described here.
  • the non-aqueous solvent is an ester or ether, and more specifically, a carbonate ester compound, a carboxylate ester compound, or a lactone compound. This is because it improves the dissociation of the electrolyte salt and also improves the mobility of the ions.
  • Carbonate compounds include cyclic carbonates and chain carbonates. Specific examples of cyclic carbonates include ethylene carbonate and propylene carbonate, while specific examples of chain carbonates include dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate.
  • Carboxylic acid ester compounds include chain carboxylates.
  • chain carboxylates include ethyl acetate, ethyl propionate, propyl propionate, and ethyl trimethylacetate.
  • Lactone compounds include lactones. Specific examples of lactones include gamma-butyrolactone and gamma-valerolactone.
  • the ethers may be 1,2-dimethoxyethane, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, anisole, etc.
  • Non-aqueous solvents include unsaturated cyclic carbonates, fluorinated cyclic carbonates, sulfonates, phosphates, acid anhydrides, nitrile compounds, and isocyanate compounds. This is because they improve the electrochemical stability of the electrolyte.
  • unsaturated cyclic carbonates include vinylene carbonate, vinylethylene carbonate, and methyleneethylene carbonate.
  • fluorinated cyclic carbonates include monofluoroethylene carbonate and difluoroethylene carbonate.
  • sulfonic acid esters include propane sultone and propene sultone.
  • phosphate esters include trimethyl phosphate and triethyl phosphate.
  • acid anhydrides include succinic anhydride, 1,2-ethanedisulfonic anhydride, and 2-sulfobenzoic anhydride.
  • nitrile compounds include succinonitrile.
  • isocyanate compounds include hexamethylene diisocyanate.
  • the non-aqueous solvent contains one or both of a carbonate ester compound and an ether. This is because a high battery capacity can be obtained in a secondary battery using the electrolyte.
  • the carbonate ester compound and the ethers are chain compounds rather than cyclic compounds. This is because the viscosity of the electrolyte solution is reduced and the solubility of the electrolyte salt is improved.
  • Specific examples of carbonate ester compounds that are chain compounds include the chain carbonate esters described above, and specific examples of ethers that are chain compounds include the 1,2-dimethoxyethane described above.
  • the method for confirming that an electrolyte contains a non-aqueous solvent is the same as the method for confirming that an electrolyte contains anisole compounds.
  • the mixing ratio of the anisole compound to the non-aqueous solvent is specified to be within a predetermined range.
  • the molar ratio of the anisole compound to the non-aqueous solvent is 1.6 or more. In other words, if the content of the non-aqueous solvent in the electrolyte is 1 mol, the content of the anisole compound in the electrolyte is 1.6 mol or more.
  • the electrolyte contains an anisole compound and a non-aqueous solvent, and the molar ratio is 1.6 or more because the mixture ratio of the anisole compound and the non-aqueous solvent is optimized, suppressing the decomposition reaction of the electrolyte when the secondary battery using the electrolyte is charged and discharged.
  • anisole compounds have the property of being less likely to coordinate with alkali metal ions than non-aqueous solvents.
  • alkali metal ions are derived from the cations contained in the electrolyte salt, and more specifically, are lithium ions, which will be described later.
  • non-aqueous solvents tend to coordinate with alkali metal ions
  • anisole compounds tend not to coordinate with alkali metal ions.
  • non-aqueous solvents that are coordinated with alkali metal ions are more susceptible to reductive decomposition than non-aqueous solvents that are not coordinated with alkali metal ions.
  • the tendency regarding reductive decomposition of non-aqueous solvents described here is also observed for anions contained in electrolyte salts.
  • anisole compounds, as described above are less likely to be coordinated with alkali metal ions and are therefore less susceptible to reductive decomposition.
  • the anisole compound is less susceptible to reductive decomposition, so by changing the type of non-aqueous solvent and the anion, it is possible to adjust the electrochemical state of the coating formed on the surface of the negative electrode, which will be described later.
  • the anisole compound contains a halogen as a constituent element.
  • a good coating containing a halogen as a constituent element is formed on the surface of the negative electrode, and the surface of the negative electrode is electrochemically protected by using the coating.
  • the decomposition reaction of the electrolyte on the surface of the negative electrode is suppressed.
  • the mixing ratio of the anisole compound and the non-aqueous solvent is optimized, and the decomposition reaction of the electrolyte is suppressed when the secondary battery using the electrolyte is charged and discharged.
  • a molar ratio of 2.0 or more is preferable, because this further suppresses the decomposition reaction of the electrolyte during charging and discharging of the secondary battery.
  • the electrolyte salt contains one or more kinds of light metal salts such as lithium salts.
  • lithium salts include lithium hexafluorophosphate ( LiPF6 ), lithium tetrafluoroborate ( LiBF4 ), lithium trifluoromethanesulfonate (LiCF3SO3), lithium bis(fluorosulfonyl)imide (LiN( FSO2 ) 2 ), lithium bis(trifluoromethanesulfonyl)imide (LiN( CF3SO2 ) 2 ), lithium tris (trifluoromethanesulfonyl)methide (LiC(CF3SO2)3), lithium bis(oxalato)borate (LiB(C2O4)2 ) , lithium monofluorophosphate ( Li2PFO3 ) , and lithium difluorophosphate ( LiPF2O2 ) . This is because a high battery capacity can be obtained.
  • LiPF6 lithium hexafluorophosphate
  • LiBF4 lithium tetrafluoroborate
  • the amount of electrolyte salt contained is not particularly limited, but is typically 0.3 mol/kg to 3.0 mol/kg relative to the solvent. This is because high ionic conductivity is obtained.
  • an electrolyte salt is added to a solvent containing an anisole compound and a non-aqueous solvent.
  • the mixing ratio of the anisole compound and the non-aqueous solvent is adjusted so that the molar ratio falls within the above-mentioned range.
  • the electrolyte salt is dispersed or dissolved in the solvent, and the electrolytic solution is prepared.
  • the electrolytic solution contains an anisole compound and a non-aqueous solvent, and the molar ratio is 1.6 or more.
  • the mixing ratio of the anisole compound and the non-aqueous solvent is optimized, and the difference between the properties of the anisole compound and the properties of the non-aqueous solvent is utilized to form a good coating on the surface of the negative electrode when the secondary battery using the electrolyte is charged and discharged.
  • the coating is used to electrochemically protect the surface of the negative electrode, suppressing the decomposition reaction of the electrolyte on the surface of the negative electrode. Therefore, since the decomposition reaction of the electrolyte is suppressed when the secondary battery is charged and discharged, a secondary battery with excellent battery characteristics can be realized using the electrolyte.
  • the decomposition reaction of the electrolyte during charging and discharging of the secondary battery is further suppressed, resulting in a greater effect.
  • the halogen group contains one or both of a fluorine group and a chlorine group, the decomposition reaction of the electrolyte is sufficiently suppressed, resulting in even greater effectiveness.
  • the solubility and compatibility of the anisole compound will improve, resulting in even greater effects.
  • the non-aqueous solvent contains one or both of a carbonate ester compound and an ether
  • a high battery capacity can be obtained in the secondary battery, and therefore a higher effect can be obtained.
  • the carbonate ester compound and the ether are each a chain compound, the viscosity of the electrolyte solution decreases and the solubility of the electrolyte salt increases, resulting in an even higher effect.
  • the secondary battery described here is a secondary battery that obtains battery capacity by utilizing the absorption and release of electrode reactants, and is equipped with a positive electrode, a negative electrode, and an electrolyte.
  • the type of electrode reactant is not particularly limited, but specifically includes 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.
  • lithium secondary battery A secondary battery that obtains battery capacity by utilizing the absorption and release of lithium is known as a lithium secondary battery (or lithium ion secondary battery). In this lithium secondary battery, lithium is absorbed and released in an ionic state.
  • the charge capacity of the negative electrode is preferably greater than the discharge capacity of the positive electrode.
  • the electrochemical capacity per unit area of the negative electrode is preferably greater 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.
  • FIG. 1 shows a perspective view of a secondary battery
  • FIG. 2 shows an enlarged cross-sectional view of a battery element 20 shown in FIG.
  • FIG. 1 the exterior film 10 and the battery element 20 are shown in a state separated from each other, and a cross section of the battery element 20 along the XZ plane is shown by a dashed line. In FIG. 2, only a portion of the battery element 20 is shown.
  • this secondary battery includes an exterior film 10, a battery element 20, a positive electrode lead 31, a negative electrode lead 32, and sealing films 41 and 42.
  • the secondary battery described here uses exterior film 10 as an exterior member for housing battery element 20. Therefore, the secondary battery shown in FIG. 1 is a so-called laminate film type secondary battery.
  • the exterior film 10 is a flexible or pliable exterior member, and has a sealed bag-like structure in which the battery element 20 is housed. As a result, the exterior film 10 houses a positive electrode 21, a negative electrode 22, a separator 23, and an electrolyte (not shown), which will be described later.
  • the exterior film 10 is a single film-like member that is folded in the folding direction F.
  • This exterior film 10 is provided with a recessed portion 10U for accommodating the battery element 20, and this recessed portion 10U is a so-called deep drawn portion.
  • the exterior film 10 is a three-layer laminate film in which a fusion layer, a metal layer, and a surface protection layer are laminated in this order from the inside, and when the exterior film 10 is folded, the outer peripheral edges of the opposing fusion layers are fused to each other.
  • the fusion layer contains a polymer compound such as polypropylene.
  • the metal layer contains a metallic material such as aluminum.
  • the surface protection layer contains a polymer compound such as nylon.
  • the configuration (number of layers) of the exterior film 10 is not particularly limited, so it may be one or two layers, or four or more layers.
  • the battery element 20 is housed in an exterior film 10.
  • the battery element 20 is a so-called power generating element, and includes a positive electrode 21, a negative electrode 22, a separator 23, and an electrolyte (not shown), as shown in Figures 1 and 2 .
  • the battery element 20 is a so-called wound electrode body, so that the positive electrode 21 and the negative electrode 22 are wound around the winding axis P while facing each other via the separator 23.
  • This winding axis P is a virtual axis extending in the Y-axis direction, as shown in FIG. 1.
  • the three-dimensional shape of the battery element 20 is not particularly limited.
  • the battery element 20 has a flat three-dimensional shape, so that the shape of the cross section (cross section along the XZ plane) of the battery element 20 intersecting the winding axis P is a flat shape defined by the major axis J1 and the minor axis J2.
  • the long axis J1 is an imaginary axis extending in the X-axis direction and has a length greater than that of the short axis J2.
  • the short axis J2 is an imaginary axis extending in the Z-axis direction intersecting the X-axis direction and has a length less than that of the long axis J1.
  • the three-dimensional shape of the battery element 20 is a flattened cylinder, and therefore the cross-sectional shape of the battery element 20 is a flattened, approximately elliptical shape.
  • 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 may be omitted.
  • the positive electrode collector 21A has a pair of surfaces on which the positive electrode active material layer 21B is provided.
  • This positive electrode collector 21A contains 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 contains one or more types of positive electrode active materials that absorb and release lithium. However, the positive electrode active material layer 21B may further contain one or more types of other materials such as a positive electrode binder and a positive electrode conductor.
  • the method of forming the positive electrode active material layer 21B is not particularly limited, but specifically includes a coating method.
  • the positive electrode active material layer 21B is provided on both sides of the positive electrode collector 21A.
  • the positive electrode active material layer 21B may be provided on only one side of the positive electrode collector 21A on the side where the positive electrode 21 faces the negative electrode 22.
  • the type of positive electrode active material is not particularly limited, but specifically includes lithium-containing compounds.
  • This lithium-containing compound is a compound that contains one or more transition metal elements as constituent elements along with lithium, and may further contain one or more other elements as constituent elements.
  • the type of other element is not particularly limited, so long as it is an element other than lithium and transition metal elements, but specifically includes elements belonging to groups 2 to 15 of the long period periodic table.
  • the type of lithium-containing compound is not particularly limited, but specifically includes oxides, phosphate compounds, silicate compounds, and borate compounds.
  • oxides include LiNiO2 , LiCoO2 , LiCo0.98Al0.01Mg0.01O2 , LiNi0.5Co0.2Mn0.3O2 , LiNi0.8Co0.15Al0.05O2 , LiNi0.33Co0.33Mn0.33O2 , Li1.2Mn0.52Co0.175Ni0.1O2 , Li1.15 ( Mn0.65Ni0.22Co0.13 ) O2 , and LiMn2O4 .
  • phosphate compounds include LiFePO4 , LiMnPO4 , LiFe0.5Mn0.5PO4 , and LiFe0.3Mn0.7PO4 .
  • the positive electrode binder contains one or more of the following materials: synthetic rubber, polymeric compound, etc.
  • synthetic rubber include styrene butadiene rubber, fluororubber, and ethylene propylene diene.
  • polymeric compounds include polyvinylidene fluoride, polyimide, and carboxymethyl cellulose.
  • the positive electrode conductive agent contains one or more conductive materials such as carbon materials, metal materials, and conductive polymer compounds.
  • conductive materials such as carbon materials, metal materials, and conductive polymer compounds.
  • Specific examples of carbon materials include graphite, carbon black, acetylene black, and ketjen black.
  • 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 may be omitted.
  • 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 contains 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 contains one or more types of negative electrode active materials that absorb and release lithium. However, the negative electrode active material layer 22B may further contain one or more types of other materials such as a negative electrode binder and a negative electrode conductor.
  • the method of forming the negative electrode active material layer 22B is not particularly limited, but specifically includes one or more types of a coating method, a gas phase method, a liquid phase method, a thermal spraying method, and a firing method (sintering method).
  • the negative electrode active material layer 22B is provided on both sides of the negative electrode collector 22A.
  • the negative electrode active material layer 22B may be provided on only one side of the negative electrode collector 22A on the side where the negative electrode 22 faces the positive electrode 21.
  • the type of negative electrode active material is not particularly limited, but specific examples include carbon materials and metal-based materials, because they provide high energy density.
  • carbon materials include graphitizable carbon, non-graphitizable carbon, and graphite.
  • the graphite may be natural graphite, artificial graphite, or both.
  • Metallic materials are a general term for materials that contain one or more of metallic elements and semi-metallic elements that can form an alloy with lithium as constituent elements, and specific examples of the metallic elements and semi-metallic elements include silicon and tin.
  • the metallic materials may be simple substances, alloys, compounds, mixtures of two or more of them, or materials containing two or more of them. However, the simple substances may contain any amount of impurities.
  • Specific examples of metallic materials include TiSi2 and SiOx (0 ⁇ x ⁇ 2 or 0.2 ⁇ x ⁇ 1.4).
  • the separator 23 is an insulating porous film interposed between the positive electrode 21 and the negative electrode 22, and allows lithium to pass through in an ionic state while preventing the occurrence of a short circuit due to contact between the positive electrode 21 and the negative electrode 22.
  • the separator 23 contains one or more types of insulating polymer compounds, and a specific example of the insulating polymer compound is polyethylene.
  • the electrolyte is impregnated into each of the positive electrode 21, the negative electrode 22, and the separator 23, and has the above-mentioned configuration. That is, the electrolyte contains an anisole compound and a non-aqueous solvent, and the molar ratio is 1.6 or more.
  • the positive electrode lead 31 is a positive electrode wiring connected to the positive electrode current collector 21A of the positive electrode 21, and is led out of the exterior film 10.
  • the positive electrode lead 31 contains one or more kinds of conductive materials such as metal materials, and a specific example of the conductive material is aluminum.
  • the shape of the positive electrode lead 31 is either a thin plate shape or a mesh shape.
  • the negative electrode lead 32 is a negative electrode wiring connected to the negative electrode current collector 22A of the negative electrode 22, and is led out to the outside of the exterior film 10.
  • the lead-out direction of the negative electrode lead 32 is the same as the lead-out direction of the positive electrode lead 31.
  • This negative electrode lead 32 contains one or more kinds of conductive materials such as metal materials, and a specific example of the conductive material is copper. Details regarding the shape of the negative electrode lead 32 are the same as the details regarding the shape of the positive electrode lead 31.
  • sealing film 41 is inserted between the exterior film 10 and the positive electrode lead 31. Also, as shown in Fig. 1, the sealing film 42 is inserted between the exterior film 10 and the negative electrode lead 32. However, one or both of the sealing films 41 and 42 may be omitted.
  • the sealing film 41 is a sealing member that prevents outside air from entering the interior of the exterior film 10.
  • This sealing film 41 contains a polymer compound such as polyolefin that has adhesion to the positive electrode lead 31, and a specific example of the polymer compound is polypropylene.
  • the configuration of the sealing film 42 is the same as that of the sealing film 41, except that the sealing film 42 is a sealing member that has adhesion to the negative electrode lead 32.
  • the sealing film 42 contains a polymer compound such as polyolefin that has adhesion to the negative electrode lead 32.
  • This secondary battery operates in the battery element 20 as follows.
  • lithium When charging, lithium is released from the positive electrode 21 and is absorbed into the negative electrode 22 via the electrolyte.
  • discharging lithium is released from the negative electrode 22 and is absorbed into the positive electrode 21 via the electrolyte.
  • discharging and charging lithium is absorbed and released in an ionic state.
  • the positive electrode 21 and the negative electrode 22 are each produced using the procedure described below as an example, and then the secondary battery is assembled and subjected to a stabilization process after assembly.
  • a positive electrode active material, a positive electrode binder, and a positive electrode conductive agent are mixed together to prepare a positive electrode mixture. Then, the positive electrode mixture is poured into a solvent to prepare a paste-like positive electrode mixture slurry.
  • the solvent may be an aqueous solvent or an organic solvent.
  • the positive electrode active material layer 21B is formed by applying the positive electrode mixture slurry to both sides of the positive electrode current collector 21A.
  • the positive electrode active material layer 21B may be compression molded using a compression device such as a roll press. In this case, the positive electrode active material layer 21B may be heated, or the compression molding may be repeated multiple times. In this way, the positive electrode active material layer 21B is formed on both sides of the positive electrode current collector 21A, and the positive electrode 21 is produced.
  • the negative electrode 22 is formed by the same procedure as the procedure for producing the positive electrode 21 described above. Specifically, a mixture (negative electrode mixture) in which the negative electrode active material, the negative electrode binder, and the negative electrode conductive agent are mixed together is poured into a solvent to prepare a paste-like negative electrode mixture slurry. Details regarding the solvent are as described above. Next, the negative electrode mixture slurry is applied to both sides of the negative electrode collector 22A to form the negative electrode active material layer 22B. After this, the negative electrode active material layer 22B may be compression molded. Details regarding the compression molding are as described above. As a result, the negative electrode active material layer 22B is formed on both sides of the negative electrode collector 22A, and the negative electrode 22 is produced.
  • the positive electrode lead 31 is connected to the positive electrode collector 21A of the positive electrode 21 using a joining method such as welding, and the negative electrode lead 32 is connected to the negative electrode collector 22A of the negative electrode 22 using a joining method such as welding.
  • the positive electrode 21 and the negative electrode 22 are stacked on top of each other with the separator 23 interposed therebetween to form a laminate (not shown).
  • the laminate is then wound to produce a wound body (not shown), which is then pressed using a compression device such as a press to form the wound body into a flat shape.
  • the wound body after this formation 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 electrolyte.
  • the exterior film 10 (adhesive layer/metal layer/surface protection layer) is folded so that the exterior films 10 face each other.
  • the outer edges of two of the opposing adhesive layers are joined to each other using an adhesive method such as heat fusion, thereby housing the roll in the bag-shaped exterior film 10.
  • a sealing film 41 is inserted between the exterior film 10 and the positive electrode lead 31, and a sealing film 42 is inserted between the exterior film 10 and the negative electrode lead 32.
  • the wound body is impregnated with the electrolyte, and the battery element 20 is produced.
  • the battery element 20 is then enclosed in the bag-shaped exterior film 10, and the secondary battery is assembled.
  • Stabilization treatment of secondary battery after assembly The assembled secondary battery is charged and discharged. Stabilization conditions such as the environmental temperature, the number of charge/discharge cycles (number of charge/discharge conditions), and the like can be set arbitrarily.
  • a coating is formed on the surface of each of the positive electrode 21 and the negative electrode 22.
  • a coating derived from the anisole compound is formed on the surface of the negative electrode 22.
  • the state of the battery element 20 becomes electrochemically stable, completing the secondary battery.
  • the electrolyte has the above-mentioned composition, and therefore, for the above-mentioned reasons, the decomposition reaction of the electrolyte is suppressed during charging and discharging of the secondary battery, thereby achieving excellent battery characteristics.
  • the secondary battery is a lithium secondary battery, sufficient battery capacity can be stably obtained by utilizing the absorption and release of lithium, resulting in even greater effects.
  • the negative electrode 22 contains a negative electrode active material that absorbs and releases lithium, and therefore the secondary battery is a lithium secondary battery (so-called lithium ion secondary battery) that utilizes the absorption and release of lithium.
  • the secondary battery may be a secondary battery that utilizes the deposition and dissolution of lithium (so-called lithium metal secondary battery).
  • the secondary battery described here has a similar configuration to the secondary battery described above, except that the negative electrode 22 contains elemental lithium (so-called lithium metal).
  • the negative electrode 22 is a lithium metal foil or the like.
  • the lithium metal may contain any amount of impurities.
  • the method for manufacturing this secondary battery is the same as the method for manufacturing the secondary battery described above, except that lithium metal is used as the negative electrode 22.
  • the battery capacity is obtained by utilizing the precipitation and dissolution of lithium, so a similar effect can be obtained.
  • a porous membrane separator 23 was used. However, although not specifically shown here, a laminated separator including a polymer compound layer may also be used.
  • the laminated separator includes a porous film and a polymer compound layer.
  • This porous film has a pair of surfaces, and the polymer compound layer is provided on one or both surfaces of the porous film. This is because the adhesion of the separator to each of the positive electrode 21 and the negative electrode 22 is improved, thereby suppressing misalignment of the battery element 20. This suppresses miswinding of the positive electrode 21, the negative electrode 22, and the separator 23, thereby suppressing swelling of the secondary battery even if a decomposition reaction of the electrolyte occurs.
  • the polymer compound layer includes polyvinylidene fluoride, etc. This is because polyvinylidene fluoride has excellent physical strength and is electrochemically stable.
  • one or both of the porous film and the polymer compound layer may contain one or more types of insulating particles. This is because the insulating particles dissipate heat when the secondary battery generates heat, improving the safety (heat resistance) of the secondary battery.
  • the insulating particles contain one or more types of insulating materials such as inorganic materials and resin materials. Specific examples of inorganic materials include aluminum oxide, aluminum nitride, boehmite, silicon oxide, titanium oxide, magnesium oxide, and zirconium oxide. Specific examples of resin materials include acrylic resin and styrene resin.
  • a precursor solution containing a polymer compound and an organic solvent is prepared, and then the precursor solution is applied to one or both sides of a porous film.
  • the precursor solution may contain multiple insulating particles.
  • the lithium can move in an ionic state between the positive electrode 21 and the negative electrode 22, so the same effect can be obtained.
  • swelling of the secondary battery is further suppressed, so a greater effect can be obtained.
  • the positive electrode 21 and the negative electrode 22 are wound facing each other with the separator 23 and the electrolyte layer interposed between them.
  • the 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 a polymer compound as well as an electrolyte solution, and the electrolyte solution is held by the polymer compound. This is because leakage of the electrolyte solution is prevented.
  • the composition of the electrolyte solution is as described above.
  • the polymer compound contains polyvinylidene fluoride, etc.
  • the lithium can move in an ionic state between the positive electrode 21 and the negative electrode 22 via the electrolyte layer, so the same effect can be obtained.
  • leakage of the electrolyte is particularly prevented as described above, so a greater effect can be obtained.
  • a secondary battery used as a power source may be a main power source or an auxiliary power source in electronic devices and electric vehicles.
  • a main power source is a power source that is used preferentially regardless of the presence or absence of other power sources.
  • An 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. Storage devices such as backup power sources and memory cards. Power tools such as electric drills and power saws. Battery packs installed in electronic devices. Medical electronic devices such as pacemakers and hearing aids. Electric vehicles such as electric cars (including hybrid cars). Power storage systems such as home or industrial battery systems that store power in preparation for emergencies. In these applications, one secondary battery may be used, or multiple secondary batteries may be used.
  • the battery pack may include a single cell or a battery pack.
  • the electric vehicle is a vehicle that runs on 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.
  • a home power storage system it is possible to use home electrical appliances and the like by utilizing the power stored in the secondary battery, which is a power storage source.
  • FIG. 3 shows the block diagram of a battery pack, which is an example of an application of a secondary battery.
  • the battery pack described here is a battery pack (a so-called soft pack) that uses 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 the 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 is connected to the outside via the positive electrode terminal 53 and the negative electrode terminal 54, and is therefore capable of charging and discharging.
  • the circuit board 52 includes a control unit 56, a switch 57, a PTC element 58 which is a thermosensitive resistor, and a temperature detection unit 59. However, the PTC element 58 may be omitted.
  • the control unit 56 includes a central processing unit (CPU) and memory, and controls the operation of the entire battery pack. This control unit 56 detects and controls the usage status of the power source 51.
  • CPU central processing unit
  • the control unit 56 turns off the switch 57 to prevent charging current from flowing through the current path of the power source 51.
  • the overcharge detection voltage is not particularly limited, but is specifically 4.20V ⁇ 0.05V, and the overdischarge detection voltage is not particularly limited, but is specifically 2.40V ⁇ 0.10V.
  • Switch 57 includes a charge control switch, a discharge control switch, a charge diode, and a discharge diode, and switches between the presence and absence of a connection between power source 51 and an external device in response to an instruction from control unit 56.
  • Switch 57 includes a field effect transistor (MOSFET) that uses a metal oxide semiconductor, and the charge current and discharge current are each detected based on the ON resistance of switch 57.
  • MOSFET field effect transistor
  • the temperature detection unit 59 includes a temperature detection element such as a thermistor. This temperature detection unit 59 measures the temperature of the power supply 51 using the temperature detection terminal 55, and outputs the temperature measurement result to the control unit 56. The temperature measurement result measured by the temperature detection unit 59 is used when the control unit 56 performs charge/discharge control in the event of abnormal heat generation, and when the control unit 56 performs correction processing when calculating the remaining capacity.
  • test secondary battery was fabricated using the following procedure: This test secondary battery was a simplified lithium metal secondary battery.
  • the anisole compound and the non-aqueous solvent were mixed together to obtain a solvent.
  • the anisole compounds used were the compound shown in formula (1-1), the compound shown in formula (1-2), the compound shown in formula (1-4), the compound shown in formula (1-5), and the compound shown in formula (1-7).
  • 1,2-dimethoxyethane (DME) was used as the non-aqueous solvent.
  • DME 1,2-dimethoxyethane
  • an electrolyte salt lithium bis(fluorosulfonyl)imide
  • an electrolyte solution Examples 1 to 7 and Comparative Examples 1 to 8
  • electrolyte solutions were prepared in the same manner as shown in Table 1, except that no anisole compound was used as the solvent, and only a non-aqueous solvent was used (Comparative Examples 9 and 10). 1,2-dimethoxyethane and anisole (ANS) were used as the non-aqueous solvent.
  • test electrode and counter electrode were then laminated together with a separator impregnated with electrolyte interposed between them. This resulted in the test electrode and counter electrode facing each other with the separator impregnated with electrolyte interposed between them, completing a test secondary battery.
  • the battery was charged at a current density of 0.22 mA/cm 2 until the total charging time reached 3 hours.
  • the battery was discharged until the voltage reached 0.1 V.
  • the secondary battery was repeatedly charged and discharged until the total number of cycles reached 25, while calculating the coulombic efficiency for each cycle.
  • the charging and discharging conditions were as described above.
  • the average Coulombic efficiency (%) which is an index for evaluating charge/discharge characteristics, was calculated by averaging the 16 Coulombic efficiencies calculated for each of the 10th to 25th cycles. This average Coulombic efficiency value was rounded off to one decimal place.
  • the battery structure of the secondary battery has been described as being of a laminate film type.
  • the battery structure of the secondary battery is not particularly limited, and may be of a cylindrical type, a square type, a coin type, a button type, etc.
  • the battery element has been described as having a wound structure.
  • the structure of the battery element is not particularly limited, and may be a stacked type or a zigzag type.
  • the positive and negative electrodes are alternately stacked with a separator between them, while in the zigzag type, the positive and negative electrodes are folded in a zigzag pattern while facing each other with the separator between them.
  • the electrode reactant is lithium in the above description, the electrode reactant is not particularly limited. Specifically, as described above, the electrode reactant may be other alkali metals such as sodium and potassium, or alkaline earth metals such as beryllium, magnesium, and calcium. In addition, the electrode reactant may be other light metals such as aluminum.
  • the present technology can also be configured as follows.
  • a positive electrode, a negative electrode, and an electrolyte solution are provided,
  • the electrolyte solution is An anisole compound represented by formula (1);
  • the molar ratio of the anisole compound to the non-aqueous solvent is 1.6 or more.
  • Secondary battery (Each of R1, R2, R3, R4, and R5 is either a hydrogen group, a halogen group, or a halogenated alkyl group. However, at least one of R1, R2, R3, R4, and R5 is either a halogen group or a halogenated alkyl group.)
  • the molar ratio is 2.0 or more.
  • the halogen group includes at least one of a fluorine group and a chlorine group.
  • the halogenated alkyl group has 5 or less carbon atoms.
  • the non-aqueous solvent contains at least one of a carbonate compound and an ether.
  • Each of the carbonate ester compound and the ethers is a chain compound.
  • the secondary battery according to ⁇ 5>. ⁇ 7> It is a lithium secondary battery.
  • ⁇ 6> The secondary battery according to any one of ⁇ 1> to ⁇ 6>.
  • ⁇ 8> An anisole compound represented by formula (1); A non-aqueous solvent; The molar ratio of the anisole compound to the non-aqueous solvent is 1.6 or more.
  • Electrolyte for secondary batteries. Each of R1, R2, R3, R4, and R5 is either a hydrogen group, a halogen group, or a halogenated alkyl group. However, at least one of R1, R2, R3, R4, and R5 is either a halogen group or a halogenated alkyl group.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Inorganic Chemistry (AREA)
  • Secondary Cells (AREA)
PCT/JP2024/028024 2023-08-09 2024-08-06 二次電池用電解液および二次電池 Pending WO2025033413A1 (ja)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2025539520A JPWO2025033413A1 (https=) 2023-08-09 2024-08-06

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2023-130082 2023-08-09
JP2023130082 2023-08-09

Publications (1)

Publication Number Publication Date
WO2025033413A1 true WO2025033413A1 (ja) 2025-02-13

Family

ID=94534838

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2024/028024 Pending WO2025033413A1 (ja) 2023-08-09 2024-08-06 二次電池用電解液および二次電池

Country Status (2)

Country Link
JP (1) JPWO2025033413A1 (https=)
WO (1) WO2025033413A1 (https=)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02207464A (ja) * 1989-02-07 1990-08-17 Showa Denko Kk 二次電池
JP2001338684A (ja) * 2000-05-26 2001-12-07 Sony Corp 非水電解質電池
JP2005135906A (ja) * 2003-10-10 2005-05-26 Mitsui Chemicals Inc 非水電解液、それを用いたリチウム二次電池
CN102938471A (zh) * 2012-12-05 2013-02-20 奇瑞汽车股份有限公司 锂离子电池用电解液及含该电解液的锂离子电池

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02207464A (ja) * 1989-02-07 1990-08-17 Showa Denko Kk 二次電池
JP2001338684A (ja) * 2000-05-26 2001-12-07 Sony Corp 非水電解質電池
JP2005135906A (ja) * 2003-10-10 2005-05-26 Mitsui Chemicals Inc 非水電解液、それを用いたリチウム二次電池
CN102938471A (zh) * 2012-12-05 2013-02-20 奇瑞汽车股份有限公司 锂离子电池用电解液及含该电解液的锂离子电池

Also Published As

Publication number Publication date
JPWO2025033413A1 (https=) 2025-02-13

Similar Documents

Publication Publication Date Title
WO2022196266A1 (ja) 二次電池
CN115349190A (zh) 二次电池
JP7517480B2 (ja) 二次電池
WO2023119947A1 (ja) リチウムイオン二次電池用電解液およびリチウムイオン二次電池
WO2025033413A1 (ja) 二次電池用電解液および二次電池
JP7726276B2 (ja) 二次電池用電解液および二次電池
JP7694715B2 (ja) 二次電池
JP7694716B2 (ja) 二次電池
JP7715362B2 (ja) 二次電池用電解液および二次電池
JP7715210B2 (ja) 二次電池用電解液および二次電池
JP7715211B2 (ja) 二次電池用電解液および二次電池
JP7761126B2 (ja) 二次電池用電解液および二次電池
JP7761127B2 (ja) 二次電池用電解液および二次電池
WO2025013623A1 (ja) 二次電池用電解液および二次電池
JP7750378B2 (ja) 二次電池用電解液および二次電池
JP7761128B2 (ja) 二次電池
JP7537504B2 (ja) 二次電池用電解液および二次電池
US20250183374A1 (en) Secondary battery
WO2024262634A1 (ja) 二次電池
JP7462142B2 (ja) 二次電池
WO2025062886A1 (ja) 二次電池
WO2025013611A1 (ja) 二次電池
WO2024150541A1 (ja) リチウムイオン二次電池用電解液およびリチウムイオン二次電池
JP2024077703A (ja) リチウムイオン二次電池
WO2024204282A1 (ja) 二次電池用正極および二次電池

Legal Events

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

Ref document number: 24851837

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2025539520

Country of ref document: JP

Kind code of ref document: A

WWE Wipo information: entry into national phase

Ref document number: 2025539520

Country of ref document: JP

NENP Non-entry into the national phase

Ref country code: DE