WO2015052775A1 - Lithium ion secondary battery and secondary battery system using same - Google Patents

Lithium ion secondary battery and secondary battery system using same Download PDF

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Publication number
WO2015052775A1
WO2015052775A1 PCT/JP2013/077357 JP2013077357W WO2015052775A1 WO 2015052775 A1 WO2015052775 A1 WO 2015052775A1 JP 2013077357 W JP2013077357 W JP 2013077357W WO 2015052775 A1 WO2015052775 A1 WO 2015052775A1
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secondary battery
lithium ion
ion secondary
mass
parts
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PCT/JP2013/077357
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French (fr)
Japanese (ja)
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阿部　誠
裕 奥山
耕平 本蔵
西村　勝憲
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株式会社日立製作所
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • 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
    • H01M10/0568—Liquid materials characterised by the solutes
    • 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
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/583—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
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • 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 average particle diameter of the lithium manganese oxide is in the range of 7 ⁇ m to less than 10 ⁇ m
  • the cyclic sulfonic acid ester is propane sultone and / or 1,3-propene sultone
  • the content of the cyclic sulfonic acid ester Ratio is 0.1 parts by mass or more and 5 parts by mass or less based on 100 parts by mass in total of the supporting salt and the non-aqueous solvent
  • the organic phosphorus compound is trimethyl phosphite, triethyl phosphite, dimethyl methyl phosphonate And at least one of diethyl methyl phosphonate
  • the content of the organic phosphorus compound is 0.1 parts by mass or more and 11 parts by mass or less with respect to 100 parts by mass in total of the support salt and the non-aqueous solvent.
  • a lithium ion secondary battery in which three items of output, capacity and long life in a secondary battery are balanced at a level higher than before.
  • a secondary battery system using the same can be provided.
  • the lithium ion secondary battery according to the present invention preferably contains lithium manganese oxide having a layered structure as a main component of the positive electrode active material for the purpose of increasing the capacity.
  • a lithium manganese oxide having a layered structure has an advantage of having a high electric capacity at the time of charge as compared with a lithium manganese oxide having a spinel structure.
  • the ratio f of Ni is preferably “0.2 ⁇ f ⁇ 0.6”, and more preferably “0.3 ⁇ e ⁇ 0.5”. In the case of “f ⁇ 0.2”, the proportion of Ni is too small, and the capacity of the secondary battery is reduced. On the other hand, in the case of “0.6 ⁇ f”, the proportion of Ni is too high, a part of Li sites is replaced with Ni, and the output of the secondary battery is reduced.
  • the non-aqueous solvent As the main component of the non-aqueous solvent, basically any conventional one can be used as long as it does not cause significant decomposition electrochemically at the positive electrode or negative electrode of a lithium ion secondary battery, but in particular ethylene carbonate (EC) It is preferable to include at least one of ethyl methyl carbonate (EMC) and dimethyl carbonate (DMC).
  • EMC ethyl methyl carbonate
  • DMC dimethyl carbonate
  • a cyclic sulfonic acid ester is used as an additive for suppressing the decomposition of the non-aqueous solvent (the reduction of the life accompanied thereby).
  • the cyclic sulfonate ester decomposes itself at the potential of the positive electrode or the negative electrode at the initial stage of battery operation to form a thin film on the electrode surface, thereby causing oxidation / reduction decomposition of other substances contained in the non-aqueous electrolyte. And has the effect of improving the life characteristics of the secondary battery.
  • propane sultone (PS) and 1,3-propene sultone (PRS) are preferable.
  • the optimum range of the content of the cyclic sulfonic acid ester changes depending on the range of the average particle diameter of the positive electrode active material (lithium manganese oxide having a layered structure).
  • the content of the cyclic sulfonic acid ester is 2.5 parts by mass to 5 parts by mass with respect to the total mass (100 parts by mass) of the support salt and the non-aqueous solvent. Is preferred.
  • the cyclic sulfonate content is preferably 0.6 parts by mass or more and 5 parts by mass or less.
  • the average particle size of the positive electrode active material is 7 ⁇ m or more and less than 10 ⁇ m, 0.1 mass
  • the cyclic sulfonic acid ester content of not less than 5 parts by mass is preferable. If the cyclic sulfonate content is less than the specified range, film formation is insufficient and the above-mentioned effects can not be obtained. On the other hand, if the amount of cyclic sulfonic acid ester is too large, the film becomes too thick, and the internal resistance of the battery significantly increases, resulting in a decrease in output. By setting the content of the cyclic sulfonic acid ester in the above range, it is possible to secure a certain level of output while achieving long life.
  • VC vinylene carbonate
  • VC forms a thin film on the surface of the negative electrode during charging of the lithium ion secondary battery, and has the effect of suppressing the decomposition of the non-aqueous solvent on the surface of the negative electrode.
  • the content of VC is preferably 0.5 parts by mass or more and 5 parts by mass or less with respect to the total mass (100 parts by mass) of the support salt and the non-aqueous solvent. If the content of VC is less than 0.5 parts by mass, the above effects become insufficient, and if it is 5 parts by mass, excessive VC is decomposed at the time of charge and discharge of the secondary battery, and the charge and discharge efficiency decreases.
  • an organophosphorus compound is added as a resistance increase inhibitor that suppresses the increase in internal resistance (the output decrease associated therewith) due to the decomposition inhibitor.
  • the addition of the organic phosphorus compound to the non-aqueous electrolyte has been performed for the purpose of imparting the non-aqueous electrolyte with flame retardancy.
  • no other effects were known.
  • the increase in internal resistance by the decomposition inhibitor is considered to be due to the resistance of the film formed on the electrode surface.
  • the electrical resistance of the film is, of course, influenced by the density and molecular structure of the film.
  • a film derived from the solvent and the electrolyte contained in itself and in the electrolytic solution is formed.
  • an element for example, phosphorus
  • the resistance of the film can be reduced while maintaining the decomposition suppressing effect.
  • organophosphorus compounds (trimethyl phosphite, triethyl phosphite, dimethyl methyl phosphonate, and diethyl methyl phosphonate) have a smaller molecular weight of the ester-linked group compared to other organophosphorus compounds.
  • the bonding group is relatively easily released and the phosphorus component is incorporated as a component of the film.
  • the agent exhibits a high effect as a resistance increase inhibitor.
  • the organic phosphorus compound content is preferably 0.1 parts by mass to 9 parts by mass, and when the particle diameter of the positive electrode active material is 7 ⁇ m or more and less than 10 ⁇ m, 0.1 parts by mass or more An organophosphorus compound content of 11 parts by mass or less is preferred.
  • the content of the organic phosphorus compound is low, the effect of suppressing the increase in resistance is insufficient, and when the content is too high, the decrease in the life due to the decomposition of the organic phosphorus compound becomes remarkable.
  • the positive electrode lead 110 is attached to the positive electrode 107, and the negative electrode lead 111 is attached to the negative electrode 108.
  • the leads 110 and 111 can have any shape such as a wire shape, a foil shape, or a plate shape.
  • the structure and material are selected so as to reduce the electrical loss and secure the chemical stability.
  • the above-mentioned positive electrode active material of the present invention is used as a positive electrode active material used for the positive electrode 107.
  • a binder, a thickener, a conductive material, a solvent, and the like are mixed with the positive electrode active material as necessary to prepare a positive electrode mixture slurry.
  • the positive electrode active material is adjusted such that the average particle size d A is “3 ⁇ m ⁇ d A ⁇ 10 ⁇ m”. More specifically, it is preferable to manage which of “3 ⁇ m ⁇ d A ⁇ 5 ⁇ m”, “5 ⁇ m ⁇ d A ⁇ 7 ⁇ m”, and “7 ⁇ m ⁇ d A ⁇ 10 ⁇ m”. Also, the maximum particle size is adjusted to be equal to or less than the thickness of the mixture layer.
  • the non-specified fine particles and coarse particles are removed by a conventional method (for example, sieve classification, air flow classification, etc.).
  • the mixing ratio of the positive electrode active material to the binder is preferably in the range of 85:15 to 95: 5 by mass. If the mass ratio of the positive electrode active material is less than 85/100, since the amount of active material is small, the chargeable / dischargeable capacity decreases and the energy density of the secondary battery decreases. On the other hand, if the mass ratio of the positive electrode active material is more than 95/100, the adhesion between the active material and the active material and the conductive material is reduced, and the contact resistance is increased, so that the output is reduced.
  • the conductive material of the positive electrode fibers produced by carbonizing conductive fibers (for example, vapor grown carbon, carbon nanotubes, pitch (petroleum, coal, coal tar, etc. by-products) at a high temperature at a high temperature, acrylic fibers
  • conductive fibers for example, vapor grown carbon, carbon nanotubes, pitch (petroleum, coal, coal tar, etc. by-products) at a high temperature at a high temperature, acrylic fibers
  • the conductive material may be a material having lower electrical resistance than the positive electrode active material, and a material that does not dissolve by oxidation at the charge / discharge potential of the positive electrode (usually 2.5 to 4.2 V). Examples include corrosion-resistant metals (such as titanium and gold), carbides (such as SiC and WC), and nitrides (such as Si 3 N 4 and BN). High specific surface area carbon materials such as carbon black and activated carbon can also be used.
  • the negative electrode active material used for the negative electrode 108 is not particularly limited as long as it is a material capable of absorbing and releasing lithium ions.
  • aluminum, silicon, tin, carbon materials eg, graphite, graphitizable carbon, non-graphitizable carbon natural graphite, artificial graphite, mesophase carbon, expanded graphite, carbon fiber, vapor grown carbon fiber, pitch-based Carbonaceous materials, needle coke, petroleum coke, polyacrylonitrile carbon fiber, carbon black, amorphous carbon, oxides (eg, lithium titanate, titanium oxide, iron oxide, vanadium oxide, antimony oxide) are available. is there.
  • Amorphous carbon is produced, for example, by thermal decomposition of a 5- or 6-membered cyclic hydrocarbon or a cyclic oxygen-containing organic compound. Any one of these or a mixture of two or more can be used.
  • carbon materials are materials having a small volume change rate at the time of insertion and extraction of lithium ions, and therefore, deterioration due to charge and discharge is small (long life), so amorphous carbon is used as a negative electrode active material. It is preferable to include.
  • conductive polymer materials polyacene, polyparaphenylene, polyaniline, polyacetylene, etc.
  • a binder, a thickener, a conductive material, a solvent, and the like are mixed as needed with the negative electrode active material to prepare a negative electrode mixture slurry.
  • the mixing ratio of the negative electrode active material to the binder is preferably in the range of 90:10 to 99: 1 by mass. If the mass ratio of the negative electrode active material is less than 90/100, since the amount of active material is small, the chargeable / dischargeable capacity decreases and the energy density of the secondary battery decreases. On the other hand, when the mass ratio of the negative electrode active material is over 99/100, the adhesion between the active material and between the active material and the conductive material is lowered, and the contact resistance is increased, whereby the output is lowered.
  • the conductive material of the negative electrode it is possible to use the same material as the positive electrode conductive material.
  • binder There is no particular limitation on the binder, the thickener and the solvent used for the positive electrode mixture slurry and the negative electrode mixture slurry, and the same ones as before can be used.
  • the separator 109 is preferably a porous body (for example, with a pore diameter of 0.01 to 10 ⁇ m and a porosity of 20 to 90%) because lithium ions need to be transmitted during charge and discharge of the secondary battery.
  • a material of the separator 109 a multilayer structure sheet in which a polyolefin-based polymer sheet (for example, polyethylene, polypropylene and the like) or a polyolefin-based polymer sheet and a fluorine-based polymer sheet (for example, polytetrafluoroethylene) are welded It can be used suitably.
  • a mixture of ceramics and a binder may be formed in a thin layer on the surface of the separator 109.
  • an ion conductive polymer such as ethylene oxide, acrylonitrile, polyvinylidene fluoride, methyl methacrylate or polyethylene oxide of hexafluoropropylene can be suitably used.
  • the separator 109 can be omitted.
  • the lithium ion secondary battery according to the present invention uses the above-described positive electrode active material and the non-aqueous electrolyte solution, a lithium ion secondary battery in which three items of capacity, output and life are balanced at a high level Can be provided. Specific examples of battery performance will be described later.
  • FIG. 2 is a schematic cross-sectional view showing an example of a secondary battery system according to the present invention. As shown in FIG. 2, in this configuration, two lithium ion secondary batteries 101 a and 101 b are connected in series. The negative electrode external terminal 105 of the lithium ion secondary battery 101 a disposed on the right side of the drawing of FIG. 2 is connected to the negative electrode input terminal of the charge / discharge control mechanism 216 by the power cable 213.
  • the positive electrode external terminal 104 of the lithium ion secondary battery 101 a is connected to the negative electrode external terminal 105 of the lithium ion secondary battery 101 b by a power cable 214. Furthermore, the positive electrode external terminal 104 of the lithium ion secondary battery 101 b is connected to the positive electrode input terminal of the charge / discharge control mechanism 216 by the power cable 215. With such a wiring configuration, the two lithium ion secondary batteries 101 a and 101 b can be charged or discharged while being controlled by the charge / discharge control mechanism 216.
  • the same components are denoted by the same reference numerals.
  • the charge / discharge control mechanism 216 exchanges power with the external device 219 via the power cables 217 and 218.
  • the external device 219 includes various external devices such as an external power source for supplying power to the charge and discharge control mechanism 216 and a regenerative motor, in addition to the external load.
  • an inverter or a converter can be provided according to the type of alternating current or direct current to which the external device corresponds.
  • the power generation device 222 is connected to the charge and discharge control mechanism 216 via the power cables 220 and 221.
  • the charge / discharge control mechanism 216 shifts to the charge mode to feed power to the external device 219 and charge the lithium ion secondary batteries 101a and 101b with surplus power.
  • the charge / discharge control mechanism 216 shifts to the discharge mode so as to supply power from the lithium ion secondary batteries 101a and 101b.
  • the charge / discharge control mechanism 216 preferably stores a program so that such mode transition is automatically performed.
  • a power generation device for example, a wind power generation device, a geothermal power generation device, a solar cell
  • a normal power generation device for example, a fuel cell, a gas turbine generator, etc.
  • the secondary battery system according to the present invention includes, for example, electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric construction machines, transport equipment, construction machines, nursing care equipment, light vehicles, electric tools, robots, island electric power. It can be used as a power supply for storage systems, space stations, etc.
  • the present invention is not limited to lithium ion batteries, and can be applied to electrochemical devices that can store and utilize electrical energy by using non-aqueous electrolytes and absorbing and releasing ions to electrodes. Since the present invention is excellent in output, it is particularly suitable for large mobile applications.
  • Example 1 (Production of Lithium Ion Secondary Battery of Examples 1 and 2) (1) Production of Positive Electrode First, a positive electrode active material (86 mass%), a conductive material (7 mass%, a mixture of graphite and carbon black), a binder (7 mass%, polyvinylidene fluoride (PVDF), manufactured by Kureha Co., Ltd. And a solvent (1-methyl-2-pyrrolidone) were prepared to prepare a positive electrode mixture slurry. As a positive electrode active material, lithium manganese oxide (average particle diameter 8 ⁇ m) having a layered structure was prepared.
  • PVDF polyvinylidene fluoride
  • this positive electrode mixture slurry was applied onto one side of a 15 ⁇ m-thick positive electrode current collector (aluminum foil) using a doctor blade method, and dried to form a positive electrode mixture layer. Then, it compression-molded by the roll press machine, it cut
  • the average particle diameter of the lithium manganese oxide in the present invention is determined by performing image analysis on an image obtained by microscopic observation of the surface or cross section of the positive electrode.
  • the average particle size was evaluated by the following procedure.
  • a positive electrode sample for evaluation was also manufactured together with a positive electrode for a secondary battery.
  • the cross section of the obtained evaluation positive electrode was observed using a scanning electron microscope (Model S-4300, manufactured by Hitachi, Ltd.) to obtain an image.
  • the diameter of a circle (equivalent circle) equivalent to the area of the particle is determined by image analysis, and the average value is taken as the average particle diameter.
  • Negative Electrode Negative electrode active material (91% by mass, amorphous carbon), binder (2% by mass, polyvinylidene fluoride (PVDF), manufactured by Kureha Co., Ltd.), conductive material (7% by mass, carbon black)
  • PVDF polyvinylidene fluoride
  • conductive material 7% by mass, carbon black
  • this negative electrode mixture slurry was applied onto one side of a negative electrode current collector (copper foil) with a thickness of 10 ⁇ m using a doctor blade method, and dried to form a negative electrode mixture layer. Then, it compression-molded by the roll press machine, it cut
  • Nonaqueous electrolyte was prepared by the following procedure. First, the non-aqueous solvent was mixed using ethylene carbonate (EC) and ethyl methyl carbonate (EMC) such that the volume ratio of EC to EMC was 1: 2. In the non-aqueous solvent, lithium hexafluorophosphate (LiPF 6 ) was dissolved to a concentration of 1 mol / L as a supporting salt.
  • EC ethylene carbonate
  • EMC ethyl methyl carbonate
  • a list of the average particle diameter of the positive electrode active material and the mixing ratio of the non-aqueous electrolytic solution additive in Examples and Comparative Examples is shown in Tables 1 to 3 described later.
  • the concentration of the support salt is the molar concentration in the non-aqueous solvent
  • the concentrations of the decomposition inhibitor and the resistance increase inhibitor are parts by mass with respect to 100 parts by mass of the support salt solution (the same applies hereinafter).
  • a lithium ion secondary battery shown in FIG. 1 was prepared.
  • Stainless steel was used for the battery container 102 and the lid 103, a porous polyethylene film with a thickness of 30 ⁇ m was used for the separator 109, and a fluorine resin was used for the insulating seal 112. Further, as shown in FIG. 1, the separator 109 is also disposed between the positive electrode 107 and the battery case 102 and between the negative electrode 108 and the battery case 102, and the positive electrode 107 and the negative electrode 108 are shorted through the battery case 102. It was not configured.
  • Example 1 in the same manner as Example 1, except that 2 parts by mass of propane sultone (PS) and 1 part by mass of VC were added as decomposition inhibitors, and 3 parts by mass of TMPI as a resistance increase inhibitor. Three lithium ion secondary batteries were produced.
  • PS propane sultone
  • TMPI TMPI
  • Example 1 (Fabrication of lithium ion secondary battery of Examples 4 to 6) Example 1 except that 3 parts by mass of triethyl phosphite (TEPI), 5 parts by mass of dimethyl methyl phosphonate (DMMP), or 3 parts by mass of diethyl methyl phosphonate (DEMP) were added as a resistance increase inhibitor.
  • TEPI triethyl phosphite
  • DMMP dimethyl methyl phosphonate
  • DEMP diethyl methyl phosphonate
  • the lithium ion secondary batteries of Examples 4 to 6 were produced in the same manner as in the above. Examples 4 to 6 are mainly examples in which the resistance increase inhibitor is different from Example 1.
  • Example 1 and Example 1 were prepared except that 2 parts by mass of PRS and 0 to 2 parts by mass of VC were added as decomposition inhibitors, and 3 parts by mass of TMPI were added as resistance increase inhibitors. Similarly, lithium ion secondary batteries of Examples 7 to 9 were produced. Examples 7 to 9 are examples for confirming the influence of VC (vinylene carbonate).
  • Example 10 A lithium ion polymer of Example 10 was prepared in the same manner as Example 8, except that a non-aqueous solvent in which ethylene carbonate (EC) and dimethyl carbonate (DMC) were mixed at a volume ratio of 1: 2 was used as the non-aqueous solvent. The following battery was produced. On the other hand, a lithium ion secondary battery of Example 11 was produced in the same manner as in Example 8 except that lithium tetrafluoroborate (LiBF 4 ) was used as a supporting salt. Examples 10 and 11 are modifications of the non-aqueous solvent and the supporting salt which are not described in Table 1 (in other words, in Table 1, the same notation as in Example 8).
  • Lithium Ion Secondary Battery of Examples 12 and 13 A layered structure lithium manganese oxide having an average particle diameter of 6 ⁇ m was used as a positive electrode active material.
  • a non-aqueous electrolyte was prepared by adding 0.6 parts by mass or 5 parts by mass of PRS and 1 part by mass of VC as a decomposition inhibitor and 0.1 parts by mass or 9 parts by mass of TMPI as a resistance increase inhibitor.
  • Lithium ion secondary batteries of Examples 12 and 13 were produced in the same manner as Example 1 except for the above.
  • Examples 12 and 13 are examples in which the average particle diameter of the positive electrode active material is mainly different from that in Example 1.
  • Lithium Ion Secondary Battery of Examples 14 and 15 A layered structure lithium manganese oxide having an average particle diameter of 3 ⁇ m was used as a positive electrode active material.
  • a non-aqueous electrolyte was prepared by adding 2.5 parts by mass or 5 parts by mass of PRS and 1 part by mass of VC as a decomposition inhibitor and 0.2 parts by mass or 5 parts by mass of TMPI as a resistance increase inhibitor.
  • Lithium ion secondary batteries of Examples 14 and 15 were produced in the same manner as Example 1 except for the above.
  • Examples 14 and 15 are also examples in which the average particle diameter of the positive electrode active material is mainly different from that in Example 1.
  • Lithium Ion Secondary Battery of Comparative Example 1 A layered structure lithium manganese oxide having an average particle size of 8 ⁇ m was used as a positive electrode active material.
  • a non-aqueous electrolyte was prepared by adding only 1 part by mass of VC (vinylene carbonate) as a decomposition inhibitor to 100 parts by mass of the supporting salt solution. In other words, cyclic sulfonic acid esters as decomposition inhibitors and resistance increase inhibitors were not added.
  • a lithium ion secondary battery of Comparative Example 1 was produced in the same manner as Example 1 except for the above. Comparative Example 1 is an example aiming to maximize the initial output of the secondary battery under the same conditions as in Example 1 with the average particle diameter of the positive electrode active material.
  • a non-aqueous electrolyte was prepared by adding 0.5 parts by mass or 3 parts by mass of PRS (1,3-propenesultone) as a decomposition inhibitor and 1 part by mass of VC to 100 parts by mass of the supporting salt solution. In other words, no resistance increase inhibitor was added.
  • the other conditions were the same as in Example 1 to fabricate lithium ion secondary batteries of Comparative Examples 2 and 3.
  • the comparative examples 2 and 3 are the examples which aimed at the maximization of the life of a secondary battery on the conditions same as Example 1 in the average particle diameter of a positive electrode active material.
  • a non-aqueous electrolyte is prepared by adding 5 parts by mass of PRS as a decomposition inhibitor and 1 part by mass of VC to 100 parts by mass of a supporting salt solution and adding 12 parts by mass of TMPI as a resistance increase inhibitor. did.
  • a lithium ion secondary battery of Comparative Example 6 was produced in the same manner as in Example 1 except for the above. Comparative Example 6 is an example in which the addition rate of the organic phosphorus compound (resistance increase inhibitor) deviates from the definition of the present invention.
  • a layered structure lithium manganese oxide (Comparative Example 7) having an average particle size of 10 ⁇ m as a positive electrode active material, a layered structure lithium manganese oxide (Comparative Example 8) having an average particle size of 6 ⁇ m, and a layered structure having an average particle size of 3 ⁇ m Lithium manganese oxide (Comparative Example 15) was prepared.
  • the other conditions were the same as in Comparative Example 1, and lithium ion secondary batteries of Comparative Examples 7, 8 and 15 were produced.
  • Comparative Examples 7, 8 and 15 are examples aiming at maximizing the initial output of the secondary battery in each positive electrode active material average particle diameter, as in Comparative Example 1.
  • discharge under standard conditions discharge under standard conditions
  • the discharge was stopped and rested (a rest time of 30 minutes was provided).
  • the cycle of “charge under standard conditions”, “rest”, “discharge under standard conditions”, and “rest” was repeated three times.
  • “charging under standard conditions” and “resting” were performed, discharge of a constant current equivalent to a 3-hour rate was started, and discharging was performed until the battery voltage reached 3.8 V.
  • this state is referred to as "half charge”.
  • an aging period of 1 week was provided and initialized.
  • (C) Life evaluation The cycle test was implemented in the following procedures using the lithium ion secondary battery which evaluated initial capacity. First, the secondary battery was placed in a thermostat of 50 ° C., and after the surface temperature of the secondary battery reached 50 ° C., the standby was performed for 12 hours. After that, the cycle of "charging under standard conditions” and “discharging under standard conditions” was repeated 2000 times without providing "rest”. The capacity (post-test capacity) of the secondary battery after the cycle test was measured, and the life (defined as the capacity after the cycle test) was evaluated. The post-test volume measurement was identical to the initial volume measurement procedure. The results are shown in Tables 4 to 6.
  • Comparative Example 7 in which the average particle diameter of the positive electrode active material was 10 ⁇ m was at the same level as that of the prior art despite the aim of maximizing the initial output. And when it made the comparative example 1 a reference
  • the non-aqueous electrolytic solution contains a cyclic sulfonic acid ester as a decomposition inhibitor and an organic phosphorus compound as a resistance increase inhibitor, but the addition amount (content ratio) thereof is inappropriate. Because of this, it was not possible to pass all three items of initial capacity, initial output and post-test capacity at the same time (initial capacity and initial output was 0.95 or more, and post-test capacity was not 0.90 or more).
  • Examples 1 to 11 according to the present invention, a positive electrode active material having an average particle diameter of 8 ⁇ m is used, and a non-aqueous electrolyte contains a cyclic sulfonic acid ester as a decomposition inhibitor and an organic phosphorus compound as a resistance increase inhibitor. It was confirmed that the level required in all items of the initial capacity, the initial output, and the volume after test was cleared by containing each in an appropriate addition amount (content rate).
  • 101, 101a, 101b lithium ion battery
  • 102 battery container
  • 103 lid
  • 104 positive electrode external terminal
  • 105 negative electrode external terminal
  • 106 injection port
  • 107 positive electrode
  • 108 negative electrode
  • 109 separator
  • 110 Positive electrode lead wire
  • 111 Negative electrode lead wire
  • 112 Insulating sealing material, 213, 214, 215, 217, 218, 220, 221 ... Power cable, 216 ... Charge / discharge control mechanism, 219 ... External equipment, 222 ... Power generation apparatus.

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Abstract

The purpose of the present invention is to provide: a lithium ion secondary battery which has a balance among the output, capacity and service life of the lithium ion secondary battery at higher levels than conventional lithium ion secondary batteries; and a secondary battery system which uses this lithium ion secondary battery. A lithium ion secondary battery according to the present invention comprises a positive electrode, a negative electrode and a nonaqueous electrolyte solution, and is characterized in that: the nonaqueous electrolyte solution contains a supporting salt, a nonaqueous solvent, a decomposition inhibitor and a resistance increase inhibitor; the decomposition inhibitor contains a cyclic sulfonic acid ester; the resistance increase inhibitor is composed of an organophosphorus compound represented by a specific chemical formula; the positive electrode contains, as a positive electrode active material, a lithium manganese oxide having a layered structure; and the lithium manganese oxide has an average particle diameter of 3 μm or more but less than 10 μm.

Description

リチウムイオン二次電池およびそれを用いた二次電池システムLithium ion secondary battery and secondary battery system using the same
　本発明は、リチウムイオン二次電池、およびそれを用いた二次電池システムに関するものである。 The present invention relates to a lithium ion secondary battery and a secondary battery system using the same.
　非水系電解液二次電池の一種であるリチウムイオン二次電池は、水系電解液二次電池（例えば、ニッケル水素電池、ニッケルカドミウム電池、鉛電池）の起電力（約1.5 V）に比して非常に高い起電力（3 V以上）を有する。そのため、リチウムイオン二次電池は、電池の小型・軽量化や大容量・高出力化に有利であり、携帯用パソコンや携帯電話機等の小型電子機器に広く用いられてきた。近年、リチウムイオン二次電池の用途は、大型電気機器（例えば、HEV（ハイブリッド自動車）やEV（電気自動車）などの自動車主動力モータ駆動用電源や、電力貯蔵用電源）にも拡大してきている。リチウムイオン二次電池を大型電気機器に適用するには、小型電子機器の場合よりも、はるかに高い出力と容量とが求められる。 The lithium ion secondary battery, which is a type of non-aqueous electrolyte secondary battery, is compared to the electromotive force (about 1.5 V) of the aqueous electrolyte secondary battery (eg, nickel hydrogen battery, nickel cadmium battery, lead battery) It has a very high electromotive force (3 V or more). Therefore, the lithium ion secondary battery is advantageous for downsizing and weight reduction of the battery and for increasing the capacity and output of the battery, and has been widely used for small electronic devices such as portable personal computers and mobile phones. In recent years, the use of lithium ion secondary batteries has been expanded to large-sized electric devices (for example, power supplies for driving automobile main power motors such as HEVs (hybrid vehicles) and EVs (electric vehicles) and power storages) . In order to apply a lithium ion secondary battery to a large-sized electrical device, much higher output and capacity are required than in the case of a small electronic device.
　高出力用途のリチウムイオン二次電池として、正極活物質にリチウムマンガン酸化物を用いたリチウムイオン電池が知られている。例えば、特許文献１（特開2007－165111号公報）には、正極シートと負極シートとがセパレータ及び非水電解液を介して形成される電極群と、前記電極群を収容するラミネート状の外装ケースと、前記正極シート及び前記負極シートのそれぞれに接続される正極リード及び負極リードと、を有する非水系二次電池において、前記正極シートに形成される正極に使用される正極活物質は、スピネル系リチウムマンガン酸化物及び層状系リチウムマンガン酸化物を含有し、前記非水系電解液は、カーボネート系の非水系溶媒にリチウム塩を溶解させた非水系溶液に、1,3ジオキソランボレート－4,5ジオンを有することを特徴とする非水系二次電池が開示されている。特許文献１によると、スピネル系マンガン酸化物を主体とした正極活物質を用いることで、貯蔵特性、サイクル寿命に優れ、低コストで、高出力なHEV用の扁平形状非水系二次電池を提供することができるとしている。 A lithium ion battery using a lithium manganese oxide as a positive electrode active material is known as a lithium ion secondary battery for high power applications. For example, in Patent Document 1 (Japanese Patent Application Laid-Open No. 2007-165111), an electrode group in which a positive electrode sheet and a negative electrode sheet are formed via a separator and a non-aqueous electrolytic solution, and a laminate type exterior housing that accommodates the electrode group. In a non-aqueous secondary battery having a case and a positive electrode lead and a negative electrode lead connected to each of the positive electrode sheet and the negative electrode sheet, a positive electrode active material used for a positive electrode formed on the positive electrode sheet is spinel The non-aqueous electrolytic solution contains a lithium-based lithium manganese oxide and a layered lithium-manganese oxide, and the non-aqueous electrolytic solution is a non-aqueous solution in which a lithium salt is dissolved in a carbonate-based non-aqueous solvent. There is disclosed a non-aqueous secondary battery characterized by having a dione. According to Patent Document 1, the use of a positive electrode active material mainly composed of spinel-based manganese oxide provides a flat-shaped non-aqueous secondary battery excellent in storage characteristics and cycle life, low in cost, and high in power for HEV. It can be done.
　また、特許文献２（特開2002－100358号公報）には、リチウム遷移金属複合酸化物を主成分とする正極活物質層を備えたリチウム二次電池において、上記リチウム遷移金属複合酸化物が、LixNiyMn1-y-zMzO2（ただし、xは０．９≦ｘ≦１．２、ｙは０．４０≦ｙ≦０．６０、ｚは０≦ｚ≦０．２であり、MはFe、Co、Cr、Al原子のいずれかから選択される）で表されるリチウム－ニッケル－マンガン－M複合酸化物と、スピネル構造（空間群Fd3m）を有しLipMn2O4（ただし、pは1≦p≦1.3である）で表されるリチウム－マンガンスピネル複合酸化物との混合物からなることを特徴とするリチウム二次電池が開示されている。特許文献２によると、ハイレートでの充放電が可能で、容量が高く、充放電サイクル耐久性に優れた非水電解液二次電池用正極材料を得ることができるとしている。 Patent Document 2 (Japanese Patent Application Laid-Open No. 2002-100358) is directed to a lithium secondary battery including a positive electrode active material layer containing lithium transition metal complex oxide as a main component, wherein the lithium transition metal complex oxide is Li x Ni y Mn 1-yz M z O 2 (where x is 0.9 ≦ x ≦ 1.2, y is 0.40 ≦ y ≦ 0.60, z is 0 ≦ z ≦ 0.2, , M is selected from any of Fe, Co, Cr, and Al atoms), and has a spinel structure (space group Fd 3 m) and a lithium-nickel-manganese-M composite oxide, and Li p Mn A lithium secondary battery is disclosed which is characterized in that it comprises a mixture with a lithium-manganese spinel composite oxide represented by 2 O 4 (where p is 1 ≦ p ≦ 1.3). According to Patent Document 2, it is possible to obtain a positive electrode material for a non-aqueous electrolyte secondary battery capable of high-rate charge and discharge, high in capacity, and excellent in charge and discharge cycle durability.
　一方で、大型電気機器用の二次電池は、小型電子機器のそれのように頻繁に交換しない（長期間の使用を前提とする）ことから、安定して長期間使用できること（すなわち、長寿命）も非常に重要である。リチウムイオン二次電池の長寿命化に関しては、非水電解液に添加剤を加える方法が知られている。 On the other hand, secondary batteries for large electric devices do not replace as frequently as those of small electronic devices (assuming long-term use), so they can be used stably and for a long time (that is, have a long life ) Is also very important. With regard to prolonging the life of a lithium ion secondary battery, a method of adding an additive to a non-aqueous electrolyte is known.
　例えば、特許文献３（特開2002－329528号公報）には、不飽和スルトンを含有する非水電解液が開示されている。特許文献３によると、不飽和スルトンを添加した電解液を使用することによって、自己放電が小さく、負荷特性、抵抗の劣化が大幅に抑制され、かつ、電池内のガス発生量が大きく減じられた非水電解液二次電池を得ることができるとしている。また、特許文献３の非水溶媒によって、低温特性、負荷特性にも優れた非水電解液二次電池を得ることができるとしている。 For example, Patent Document 3 (Japanese Patent Laid-Open No. 2002-329528) discloses a non-aqueous electrolytic solution containing unsaturated sultone. According to Patent Document 3, by using an electrolytic solution to which unsaturated sultone is added, the self-discharge is small, the deterioration of the load characteristics and the resistance is significantly suppressed, and the gas generation amount in the battery is greatly reduced. It is stated that a non-aqueous electrolyte secondary battery can be obtained. Moreover, it is supposed that the non-aqueous electrolyte secondary battery excellent in low temperature characteristics and load characteristics can be obtained by the non-aqueous solvent described in Patent Document 3.
　また、特許文献４（特開平11－260401号公報）には、所定の一般式で表わされるビニレンカーボネート誘導体とリン酸エステル化合物とを含む非水溶媒と、電解質とからなることを特徴とする非水電解液が開示されている。特許文献４によると、難燃性が高く安全で、高電圧を発生でき、かつ充放電性能の優れた非水電解液を提供することができるとしている。 In addition, Patent Document 4 (Japanese Patent Application Laid-Open No. 11-260401) discloses a non-aqueous solvent comprising a vinylene carbonate derivative represented by a predetermined general formula and a phosphoric acid ester compound, and an electrolyte. A water electrolyte is disclosed. According to Patent Document 4, it is possible to provide a non-aqueous electrolyte which is highly flame retardant and safe, can generate a high voltage, and has excellent charge and discharge performance.
特開２００７－１６５１１１号公報JP 2007-165111 A 特開２００２－１００３５８号公報Japanese Patent Application Laid-Open No. 2002-100358 特開２００２－３２９５２８号公報JP 2002-329528 A 特開平１１－２６０４０１号公報Japanese Patent Application Laid-Open No. 11-260401
　リチウムイオン二次電池に対する高出力・高容量・長寿命の要求は、近年ますます高まっている。特に、自動車の主動力モータ駆動用電源においては、更なる高出力化・高容量化・長寿命化の強い要求がある。 Demands for high output, high capacity and long life for lithium ion secondary batteries are increasing in recent years. In particular, in a power supply for driving a main power motor of an automobile, there is a strong demand for further higher output, higher capacity, and longer life.
　前述したように、従来のリチウムイオン二次電池では、高出力・高容量を実現するために正極活物質にリチウムマンガン酸化物（スピネル系リチウムマンガン酸化物および層状系リチウムマンガン酸化物）を用いている。しかしながら、高出力化を追求するためにスピネル系リチウムマンガン酸化物の比率を高めると、要求される高容量や長寿命化の達成が困難になる場合があった。高容量化を追求するために層状系リチウムマンガン酸化物の比率を高めると、要求される高出力化の達成が困難になる場合があった。 As described above, in a conventional lithium ion secondary battery, lithium manganese oxide (spinel lithium manganese oxide and layered lithium manganese oxide) is used as a positive electrode active material to achieve high output and high capacity. There is. However, if the ratio of spinel lithium manganese oxide is increased to pursue high output, it may be difficult to achieve the required high capacity and long life. If the ratio of layered lithium manganese oxide is increased to pursue higher capacity, it may be difficult to achieve the required high power.
　なお、電極活物質（正極活物質、負極活物質）の粒径を小さくすると、高出力化に有効であることが一般的に知られている。ただし、電極活物質の小粒径化は、寿命特性を大きく劣化させることも一般的に知られている。 It is generally known that reducing the particle size of the electrode active material (positive electrode active material, negative electrode active material) is effective for achieving high output. However, it is generally known that the particle size reduction of the electrode active material significantly deteriorates the life characteristics.
　また、要求される長寿命化を実現するために非水電解液に各種添加剤を加えると、要求される高出力・高容量の達成が困難になる場合があった。すなわち、従来技術の単純な延長線上では、高出力化・高容量化・長寿命化の３項目において要求されるレベルを十分に満たせない問題があった。 In addition, when various additives are added to the non-aqueous electrolyte in order to realize the required long life, it may be difficult to achieve the required high output and high capacity. That is, in the simple extension of the prior art, there is a problem that the level required in the three items of high output, high capacity, and long life can not be sufficiently satisfied.
　したがって、本発明の目的は、リチウムイオン二次電池の出力、容量および寿命の３項目を従来よりも高いレベルでバランスさせたリチウムイオン二次電池、およびそれを用いた二次電池システムを提供することにある。 Therefore, an object of the present invention is to provide a lithium ion secondary battery in which three items of output, capacity and life of the lithium ion secondary battery are balanced at a higher level than before, and a secondary battery system using the same. It is.
　（I）本発明の一態様は、正極、負極および非水電解液を備えたリチウムイオン二次電池であって、前記非水電解液は支持塩と非水溶媒と分解抑制剤と抵抗上昇抑制剤とを含み、前記分解抑制剤は環状スルホン酸エステルを含み、前記抵抗上昇抑制剤は、下記一般化学式（１）および/または（２）で表される有機リン化合物（ただし、化学式中のR1～R6はそれぞれ一般式CnH2n+1（nは0または正の整数）で表される基である）からなり、前記正極は、正極活物質として層状構造を有するリチウムマンガン酸化物を含み、該リチウムマンガン酸化物の平均粒径が3μm以上10μm未満であることを特徴とするリチウムイオン二次電池を提供する。 (I) One aspect of the present invention is a lithium ion secondary battery comprising a positive electrode, a negative electrode and a non-aqueous electrolyte, wherein the non-aqueous electrolyte comprises a support salt, a non-aqueous solvent, a decomposition inhibitor and suppression of resistance increase And the decomposition inhibitor includes a cyclic sulfonic acid ester, and the resistance increase inhibitor is an organophosphorus compound represented by the following general chemical formula (1) and / or (2) (with the proviso that R in the chemical formula is 1 to R 6 each are a group represented by a general formula C n H 2n + 1 (n is 0 or a positive integer), and the positive electrode is a lithium manganese oxide having a layered structure as a positive electrode active material And the lithium manganese oxide has an average particle size of 3 μm or more and less than 10 μm.
Figure JPOXMLDOC01-appb-C000003
Figure JPOXMLDOC01-appb-C000003
Figure JPOXMLDOC01-appb-C000004
Figure JPOXMLDOC01-appb-C000004
　なお、本発明において、リチウムマンガン酸化物の平均粒径とは、正極の表面または断面の顕微鏡観察による像に対して画像解析を行って求めたものと定義する。例えば、走査型電子顕微鏡により正極の表面または断面を観察して画像を取得し、取得した画像内の正極活物質の各粒子に対して、該粒子の面積と等価面積になる円（等価円）の直径を求め、その平均値を平均粒径とする。 In the present invention, the average particle diameter of lithium manganese oxide is defined as one obtained by performing image analysis on an image obtained by microscopic observation of the surface or cross section of the positive electrode. For example, the surface or cross section of the positive electrode is observed by a scanning electron microscope to obtain an image, and for each particle of the positive electrode active material in the obtained image, a circle equivalent to the area of the particle (equivalent circle) The diameter of the particle is determined, and the average value is taken as the average particle diameter.
　また、本発明は、上記の発明に係るリチウムイオン二次電池（I）において、以下のような改良や変更を加えることができる。
（i）前記リチウムマンガン酸化物の平均粒径が3μm以上5μm未満の範囲にあり、前記環状スルホン酸エステルは、プロパンスルトンおよび/または1,3-プロペンスルトンであり、該環状スルホン酸エステルの含有率が前記支持塩と前記非水溶媒との合計100質量部に対して2.5質量部以上5質量部以下であり、前記有機リン化合物は、亜リン酸トリメチル、亜リン酸トリエチル、ジメチルメチルホスホナートおよびジエチルメチルホスホナートの内の少なくとも１種であり、該有機リン化合物の含有率が前記支持塩と前記非水溶媒との合計100質量部に対して0.2質量部以上5質量部以下である。
（ii）前記リチウムマンガン酸化物の平均粒径が5μm以上7μm未満の範囲にあり、前記環状スルホン酸エステルは、プロパンスルトンおよび/または1,3-プロペンスルトンであり、該環状スルホン酸エステルの含有率が前記支持塩と前記非水溶媒との合計100質量部に対して0.6質量部以上5質量部以下であり、前記有機リン化合物は、亜リン酸トリメチル、亜リン酸トリエチル、ジメチルメチルホスホナートおよびジエチルメチルホスホナートの内の少なくとも１種であり、該有機リン化合物の含有率が前記支持塩と前記非水溶媒との合計100質量部に対して0.1質量部以上9質量部以下である。
（iii）前記リチウムマンガン酸化物の平均粒径が7μm以上10μm未満の範囲にあり、前記環状スルホン酸エステルは、プロパンスルトンおよび/または1,3-プロペンスルトンであり、該環状スルホン酸エステルの含有率が前記支持塩と前記非水溶媒との合計100質量部に対して0.1質量部以上5質量部以下であり、前記有機リン化合物は、亜リン酸トリメチル、亜リン酸トリエチル、ジメチルメチルホスホナートおよびジエチルメチルホスホナートの内の少なくとも１種であり、該有機リン化合物の含有率が前記支持塩と前記非水溶媒との合計100質量部に対して0.1質量部以上11質量部以下である。
（iv）前記分解抑制剤は、ビニレンカーボネートを更に含む。該ビニレンカーボネートの含有率は支持塩と非水溶媒との合計100質量部に対して0.5質量部以上5質量部以下である。
（v）前記リチウムマンガン酸化物は、LidMneNifCogQhO2（ただし、d＋e＋f＋g＋h＝2、1.0≦d≦1.2、0.1≦e≦0.5、0.2≦f≦0.6、0.1≦g≦0.5、0≦h≦0.1、QはB、Mg、Al、Cu、Zn、MoおよびWからなる群より選ばれる少なくとも１種である)で表わされる化合物である。
（vi）前記非水溶媒は、その主成分として、エチレンカーボネート、エチルメチルカーボネートおよびジメチルカーボネートの内の少なくとも１種を含む。
（vii）前記支持塩は、六フッ化リン酸リチウムおよび/または四フッ化ホウ酸リチウムを含む。
（viii）前記負極は、負極活物質として非晶質炭素を含む。 In the lithium ion secondary battery (I) according to the above invention, the present invention can be modified or changed as follows.
(I) The average particle diameter of the lithium manganese oxide is in the range of 3 μm to 5 μm, and the cyclic sulfonic acid ester is propane sultone and / or 1,3-propene sultone, and the content of the cyclic sulfonic acid ester Ratio is 2.5 parts by mass or more and 5 parts by mass or less with respect to a total of 100 parts by mass of the supporting salt and the non-aqueous solvent, and the organic phosphorus compound is trimethyl phosphite, triethyl phosphite, dimethyl methyl phosphonate And at least one of diethyl methyl phosphonate, and the content of the organic phosphorus compound is 0.2 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass in total of the support salt and the non-aqueous solvent.
(Ii) The average particle diameter of the lithium manganese oxide is in the range of 5 μm to less than 7 μm, the cyclic sulfonic acid ester is propane sultone and / or 1,3-propene sultone, and the content of the cyclic sulfonic acid ester Ratio is 0.6 parts by mass or more and 5 parts by mass or less with respect to a total of 100 parts by mass of the support salt and the non-aqueous solvent, and the organic phosphorus compound is trimethyl phosphite, triethyl phosphite, dimethyl methyl phosphonate And at least one of diethyl methyl phosphonate, and the content of the organic phosphorus compound is 0.1 parts by mass or more and 9 parts by mass or less with respect to 100 parts by mass in total of the support salt and the non-aqueous solvent.
(Iii) The average particle diameter of the lithium manganese oxide is in the range of 7 μm to less than 10 μm, the cyclic sulfonic acid ester is propane sultone and / or 1,3-propene sultone, and the content of the cyclic sulfonic acid ester Ratio is 0.1 parts by mass or more and 5 parts by mass or less based on 100 parts by mass in total of the supporting salt and the non-aqueous solvent, and the organic phosphorus compound is trimethyl phosphite, triethyl phosphite, dimethyl methyl phosphonate And at least one of diethyl methyl phosphonate, and the content of the organic phosphorus compound is 0.1 parts by mass or more and 11 parts by mass or less with respect to 100 parts by mass in total of the support salt and the non-aqueous solvent.
(Iv) The decomposition inhibitor further contains vinylene carbonate. The content of the vinylene carbonate is 0.5 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass in total of the support salt and the non-aqueous solvent.
(V) the lithium manganese oxide, Li d Mn e Ni f Co g Q h O 2 ( however, d + e + f + g + h = 2,1.0 ≦ d ≦ 1.2,0.1 ≦ e ≦ 0.5,0.2 ≦ f ≦ 0.6,0.1 ≦ g 0.5, 0 ≦ h ≦ 0.1, and Q is at least one selected from the group consisting of B, Mg, Al, Cu, Zn, Mo and W).
(Vi) The non-aqueous solvent contains, as its main component, at least one of ethylene carbonate, ethyl methyl carbonate and dimethyl carbonate.
(Vii) The support salt contains lithium hexafluorophosphate and / or lithium tetrafluoroborate.
(Viii) The negative electrode contains amorphous carbon as a negative electrode active material.
　（II）本発明の他の一態様は、上述したリチウムイオン二次電池を用いた二次電池システムを提供する。 (II) Another aspect of the present invention provides a secondary battery system using the above-described lithium ion secondary battery.
　本発明によれば、二次電池における出力、容量および長寿命の３項目を従来よりも高いレベルでバランスさせたリチウムイオン二次電池を提供することができる。また、それを用いた二次電池システムを提供することができる。 According to the present invention, it is possible to provide a lithium ion secondary battery in which three items of output, capacity and long life in a secondary battery are balanced at a level higher than before. In addition, a secondary battery system using the same can be provided.
本発明に係るリチウムイオン二次電池の一例を示す断面模式図である。It is a cross-sectional schematic diagram which shows an example of the lithium ion secondary battery which concerns on this invention. 本発明に係る二次電池システムの一例を示す断面模式図である。BRIEF DESCRIPTION OF THE DRAWINGS It is a cross-sectional schematic diagram which shows an example of the secondary battery system which concerns on this invention.
　（本発明の基本思想）
　本発明者等は、リチウムイオン二次電池の高出力化、高容量化および長寿命化を同時に達成するために、正極活物質および非水電解液への各種添加剤について鋭意研究した。その結果、（１）正極活物質の平均粒径を所定の範囲に制御すること、（２）非水電解液の分解抑制剤として環状スルホン酸エステルを添加すること、および（３）添加した分解抑制剤の作用を制御するために抵抗上昇抑制剤として有機リン化合物を添加することを組み合わせることにより、出力、容量および寿命の３項目を非常に高いレベルでバランスさせられることを見出した。本発明は、当該知見に基づいて完成されたものである。 (Basic thought of the present invention)
The present inventors diligently studied various additives to the positive electrode active material and the non-aqueous electrolyte in order to simultaneously achieve high output, high capacity and long life of the lithium ion secondary battery. As a result, (1) controlling the average particle diameter of the positive electrode active material in a predetermined range, (2) adding a cyclic sulfonic acid ester as a decomposition inhibitor of the non-aqueous electrolyte, and (3) decomposition added By combining the addition of an organophosphorus compound as a resistance increase inhibitor to control the action of the inhibitor, it has been found that the three items of output, capacity and life can be balanced at a very high level. The present invention has been completed based on the findings.
　以下、本発明に係る実施形態について、より具体的に説明する。ただし、本発明は、ここで取り上げた実施形態に限定されることはなく、発明の技術的思想を逸脱しない範囲で適宜組み合わせや改良が可能ある。 Hereinafter, embodiments according to the present invention will be more specifically described. However, the present invention is not limited to the embodiments described here, and appropriate combinations and improvements can be made without departing from the technical concept of the invention.
　（リチウムイオン二次電池の正極活物質）
　本発明に係るリチウムイオン二次電池は、高容量化を目的として、層状構造を有するリチウムマンガン酸化物を正極活物質の主成分とすることが好ましい。層状構造を有するリチウムマンガン酸化物は、スピネル構造を有するリチウムマンガン酸化物と比較して充電時の電気容量が高い利点がある。 (Positive electrode active material of lithium ion secondary battery)
The lithium ion secondary battery according to the present invention preferably contains lithium manganese oxide having a layered structure as a main component of the positive electrode active material for the purpose of increasing the capacity. A lithium manganese oxide having a layered structure has an advantage of having a high electric capacity at the time of charge as compared with a lithium manganese oxide having a spinel structure.
　層状構造を有するリチウムマンガン酸化物としては、六方晶系の単位格子が層状に積層されたものが好ましい。さらに、当該リチウムマンガン酸化物は、リチウム（Li）とマンガン（Mn）と他の遷移金属との複合化合物であることが好ましい。特に、リチウムイオン二次電池の高出力化および高エネルギー密度化の観点から、LiとMnとNi（ニッケル）とCo（コバルト）とを少なくとも含有する化合物が好ましい。 The lithium manganese oxide having a layered structure is preferably one in which hexagonal unit cells are stacked in a layered manner. Furthermore, it is preferable that the said lithium manganese oxide is a composite compound of lithium (Li), manganese (Mn), and other transition metals. In particular, a compound containing at least Li, Mn, Ni (nickel) and Co (cobalt) is preferable from the viewpoint of achieving high output and high energy density of a lithium ion secondary battery.
　具体的には、LidMneNifCogQhO2で表わされる化合物が好適に用いられる。当該リチウムマンガン酸化物は、LiMnO2中のMnの一部をLi、Ni、Coおよび所定の元素Qで置換したものである。このようにMnの一部をLi、Ni、Coおよび所定の元素Qで置換することによって、リチウムイオン二次電池の高出力化、高エネルギー密度化および長寿命化を向上させることができる。Qは、Fe（鉄）、V（バナジウム）、Ti（チタン）、Cu（銅）、Al（アルミニウム）、Sn（スズ）、Zn（亜鉛）、Mg（マグネシウム）およびB（ホウ素）からなる群より選ばれる少なくとも一種が好ましく、結晶構造の安定性向上による寿命向上に貢献する。 Specifically, the compound represented by Li d Mn e Ni f Co g Q h O 2 is preferably used. The lithium manganese oxide is obtained by substituting a part of Mn in LiMnO 2 with Li, Ni, Co and a predetermined element Q. As described above, by substituting a part of Mn with Li, Ni, Co and a predetermined element Q, it is possible to improve the high output, high energy density and long life of the lithium ion secondary battery. Q is a group consisting of Fe (iron), V (vanadium), Ti (titanium), Cu (copper), Al (aluminum), Sn (tin), Zn (zinc), Mg (magnesium) and B (boron) At least one selected from the above is preferable, and contributes to the improvement of the life by improving the stability of the crystal structure.
　Li、Mn、Ni、CoおよびQの比率の和「d＋e＋f＋g＋h」は、LiMnO2の層状構造を維持するために、「d＋e＋f＋g＋h＝2」とすることが好ましい。「d＋e＋f＋g＋h≠2」の場合には、LiMnO2の層状構造が不安定になりやすくなる。 The sum “d + e + f + g + h” of the ratio of Li, Mn, Ni, Co and Q is preferably “d + e + f + g + h = 2” to maintain the layered structure of LiMnO 2 . In the case of “d + e + f + g + h ≠ 2”, the layered structure of LiMnO 2 tends to be unstable.
　リチウムマンガン酸化物中のLiの比率dは、「1.0≦d≦1.2」であることが好ましく、「1.02≦d≦1.12」であることがより好ましい。「d＜1.0」の場合には、Liサイトの一部を他の構成元素、特にイオン半径の近いNiが置換するため、Liイオンの拡散が阻害されて電池の出力が低下する。一方、「1.2＜d」の場合には、Mn等の遷移金属のイオン量とLiイオン量とのバランスが崩れるため、二次電池の容量が低下してしまう。 The ratio d of Li in the lithium manganese oxide is preferably “1.0 ≦ d ≦ 1.2”, more preferably “1.02 ≦ d ≦ 1.12”. In the case of “d <1.0”, a part of the Li site is replaced with another constituent element, in particular, Ni near the ion radius, so that the diffusion of Li ions is inhibited and the output of the battery is reduced. On the other hand, in the case of “1.2 <d”, the balance between the ion amount of the transition metal such as Mn and the Li ion amount is lost, and the capacity of the secondary battery is lowered.
　Mnの比率eは、「0.1≦e≦0.5」であることが好ましく、「0.2≦e≦0.4」であることがより好ましい。「e＜0.1」の場合、Mnの割合が小さ過ぎて結晶構造が不安定となり、寿命が低下してしまう。一方、「0.5＜e」の場合、結晶の電池的中性を保つためにMnイオンの平均価数が3に近づき、ヤーン・テラー歪みによって結晶構造が不安定となり、寿命が低下してしまう。 The ratio e of Mn is preferably “0.1 ≦ e ≦ 0.5”, and more preferably “0.2 ≦ e ≦ 0.4”. In the case of “e <0.1”, the proportion of Mn is too small, the crystal structure becomes unstable, and the life decreases. On the other hand, in the case of “0.5 <e”, the average valence number of Mn ions approaches 3 in order to maintain the battery neutrality of the crystal, the crystal structure becomes unstable due to the Yarn-Teller distortion, and the life decreases.
　Niの比率fは、「0.2≦f≦0.6」であることが好ましく、「0.3≦e≦0.5」であることがより好ましい。「f＜0.2」の場合、Niの割合が小さ過ぎて二次電池の容量が低下してしまう。一方、「0.6＜f」の場合、Niの割合が高過ぎてLiサイトの一部がNiで置換され、二次電池の出力が低下してしまう。 The ratio f of Ni is preferably “0.2 ≦ f ≦ 0.6”, and more preferably “0.3 ≦ e ≦ 0.5”. In the case of “f <0.2”, the proportion of Ni is too small, and the capacity of the secondary battery is reduced. On the other hand, in the case of “0.6 <f”, the proportion of Ni is too high, a part of Li sites is replaced with Ni, and the output of the secondary battery is reduced.
　Coの比率gは、「0.1≦g≦0.5」であることが好ましく、「0.2≦g≦0.4」であることがより好ましい。「g＜0.1」の場合、Coの割合が小さ過ぎて結晶構造が不安定となり、寿命が低下してしまう。一方、「0.5＜g」の場合、高価なCoの割合が高くなるため材料コストが増大してしまう。 The ratio g of Co is preferably “0.1 ≦ g ≦ 0.5”, and more preferably “0.2 ≦ g ≦ 0.4”. In the case of “g <0.1”, the proportion of Co is too small, the crystal structure becomes unstable, and the life decreases. On the other hand, in the case of “0.5 <g”, the proportion of expensive Co is high, and the material cost is increased.
　Qの比率hは、「0≦h≦0.1」が好ましく、「0≦h≦0.06」であることがより好ましい。「0.1＜h」の場合には、Mn等の遷移金属のイオン量が低下し、二次電池の容量が低下してしまう。 The ratio h of Q is preferably “0 ≦ h ≦ 0.1”, more preferably “0 ≦ h ≦ 0.06”. In the case of “0.1 <h”, the amount of ions of transition metal such as Mn decreases, and the capacity of the secondary battery decreases.
　また、本発明で用いる層状構造を有するリチウムマンガン酸化物は、その平均粒径dAの範囲が「3μm≦dA＜10μm」であることが好ましい。前述したように、正極活物質の粒径が小さくなると、比表面積が大きくなるため二次電池の出力は向上するが、非水電解液の分解が促進されて寿命特性が低下する傾向がある。一方、粒径が大きくなると、比表面積が小さくなるため、非水電解液の分解が抑制されて寿命特性は向上するが、出力が十分に得られなくなる傾向がある。 In addition, it is preferable that the range of the average particle diameter d A of the lithium manganese oxide having a layered structure used in the present invention is “3 μm ≦ d A <10 μm”. As described above, when the particle diameter of the positive electrode active material is reduced, the specific surface area is increased and the output of the secondary battery is improved. However, the decomposition of the non-aqueous electrolyte tends to be promoted and the life characteristics tend to be deteriorated. On the other hand, when the particle size is increased, the specific surface area is decreased, so that the decomposition of the non-aqueous electrolyte is suppressed and the life characteristics are improved, but there is a tendency that the output can not be obtained sufficiently.
　これに対し、本発明は、層状構造を有するリチウムマンガン酸化物の平均粒径dAを上記の範囲に制御し、後述する分解抑制剤および抵抗上昇抑制剤と組み合わせることで、寿命特性の低下を抑制しながら出力を向上させるものである。リチウムマンガン酸化物の平均粒径が上記範囲を外れると、分解抑制剤および抵抗上昇抑制剤と組み合わせても、本発明の作用効果を十分に享受できなくなる。より具体的には、「3μm≦dA＜5μm」の範囲、「5μm≦dA＜7μm」の範囲、および「7μm≦dA＜10μm」の範囲に分けて管理した上、分解抑制剤および抵抗上昇抑制剤の混合率を制御する（詳細は後述する）。 On the other hand, the present invention controls the average particle diameter d A of the lithium manganese oxide having a layered structure within the above range, and reduces the life characteristics by combining it with the decomposition inhibitor and the resistance increase inhibitor described later. It is intended to improve the output while suppressing. If the average particle size of the lithium manganese oxide is out of the above range, even if it is combined with the decomposition inhibitor and the resistance increase inhibitor, the effect of the present invention can not be sufficiently obtained. More specifically, the decomposition inhibitor and the decomposition inhibitor are divided into a range of “3 μm ≦ d A <5 μm”, a range of “5 μm ≦ d A <7 μm”, and a range of “7 μm ≦ d A <10 μm” Control the mixing ratio of the resistance increase inhibitor (details will be described later).
　（非水電解液）
　本発明に係るリチウムイオン二次電池の非水電解液は、支持塩と非水溶媒と分解抑制剤と抵抗上昇抑制剤とを含む。分解抑制剤は環状スルホン酸エステルを含み、所定の比率で非水電解液に混合される。また、抵抗増加抑制剤は所定の化学式で表される有機リン化合物からなり、所定の比率で非水電解液に混合される。 (Non-aqueous electrolyte)
The non-aqueous electrolyte solution of the lithium ion secondary battery according to the present invention includes a support salt, a non-aqueous solvent, a decomposition inhibitor, and a resistance increase inhibitor. The decomposition inhibitor contains cyclic sulfonic acid ester and is mixed with the non-aqueous electrolyte in a predetermined ratio. Further, the resistance increase inhibitor is composed of an organic phosphorus compound represented by a predetermined chemical formula, and is mixed with the non-aqueous electrolyte at a predetermined ratio.
　まず、非水溶媒について説明する。非水溶媒の主成分としては、リチウムイオン二次電池の正極あるいは負極で電気化学的に著しく分解を生じないものであれば基本的に従前のものを利用できるが、特に、エチレンカーボネート（EC）、エチルメチルカーボネート（EMC）およびジメチルカーボネート（DMC）のうちの少なくとも１種を含むことは好ましい。 First, the non-aqueous solvent will be described. As the main component of the non-aqueous solvent, basically any conventional one can be used as long as it does not cause significant decomposition electrochemically at the positive electrode or negative electrode of a lithium ion secondary battery, but in particular ethylene carbonate (EC) It is preferable to include at least one of ethyl methyl carbonate (EMC) and dimethyl carbonate (DMC).
　また、非水溶媒の副成分として、プロピレンカーボネート、ブチレンカーボネート、γ-ブチロラクトン、ジエチルカーボネート、メチルエチルカーボネート、1,2-ジメトキシエタン、2-メチルテトラヒドロフラン、ジメチルスルフォキシド、1,3-ジオキソラン、ホルムアミド、ジメチルホルムアミド、プロピオン酸メチル、プロピオン酸エチル、リン酸トリエステル、トリメトキシメタン、ジオキソラン、ジエチルエーテル、スルホラン、3-メチル-2-オキサゾリジノン、テトラヒドロフラン、1,2-ジエトキシエタン、クロルエチレンカーボネート、クロルプロピレンカーボネートのいずれかの単体または混合物を適宜利用することができる。これら副成分の合計含有率は、非水溶媒の合計100体積％に対して、30体積％以下とすることが好ましい。 In addition, propylene carbonate, butylene carbonate, γ-butyrolactone, diethyl carbonate, methyl ethyl carbonate, 1,2-dimethoxyethane, 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, and the like as auxiliary components of the non-aqueous solvent Formamide, dimethylformamide, methyl propionate, ethyl propionate, phosphoric acid triester, trimethoxymethane, dioxolane, diethyl ether, sulfolane, 3-methyl-2-oxazolidinone, tetrahydrofuran, 1,2-diethoxyethane, chlorethylene carbonate Any one or a mixture of chloropropylene carbonates can be appropriately used. The total content of these subcomponents is preferably 30% by volume or less based on 100% by volume of the total amount of the non-aqueous solvent.
　次に、分解抑制剤について説明する。本発明では、非水溶媒の分解（それに伴う寿命低下）を抑制するための添加剤として環状スルホン酸エステルを用いる。環状スルホン酸エステルは、電池動作の初期段階において、正極または負極の電位で自身が分解して電極表面に薄い被膜を形成することで、非水電解液中に含まれる他物質の酸化・還元分解を抑制し、二次電池の寿命特性を向上させる効果を有する。本発明で用いる環状スルホン酸エステルとしては、プロパンスルトン（PS）、1,3-プロペンスルトン（PRS）が好ましい。 Next, the decomposition inhibitor will be described. In the present invention, a cyclic sulfonic acid ester is used as an additive for suppressing the decomposition of the non-aqueous solvent (the reduction of the life accompanied thereby). The cyclic sulfonate ester decomposes itself at the potential of the positive electrode or the negative electrode at the initial stage of battery operation to form a thin film on the electrode surface, thereby causing oxidation / reduction decomposition of other substances contained in the non-aqueous electrolyte. And has the effect of improving the life characteristics of the secondary battery. As the cyclic sulfonic acid ester used in the present invention, propane sultone (PS) and 1,3-propene sultone (PRS) are preferable.
　環状スルホン酸エステルの含有率は、正極活物質（層状構造を有するリチウムマンガン酸化物）の平均粒径の範囲によって、その最適範囲が変化する。正極活物質の平均粒径が3μm以上5μm未満の場合、支持塩と非水溶媒との総質量（100質量部）に対して、環状スルホン酸エステルの含有率は2.5質量部以上5質量部以下が好ましい。正極活物質の平均粒径が5μm以上7μm未満の場合は0.6質量部以上5質量部以下の環状スルホン酸エステル含有率が好ましく、正極活物質の平均粒径が7μm以上10μm未満の場合は0.1質量部以上5質量部以下の環状スルホン酸エステル含有率が好ましい。環状スルホン酸エステル含有率が、規定より少ないと被膜形成が不十分となり上述の作用効果が得られない。一方で、環状スルホン酸エステルが多過ぎると被膜が厚くなり過ぎて、電池の内部抵抗が著しく上昇して出力低下を招く。環状スルホン酸エステルの含有率を当該範囲とすることで、長寿命化を果たしながら、ある程度の出力を確保することができる。 The optimum range of the content of the cyclic sulfonic acid ester changes depending on the range of the average particle diameter of the positive electrode active material (lithium manganese oxide having a layered structure). When the average particle size of the positive electrode active material is 3 μm to 5 μm, the content of the cyclic sulfonic acid ester is 2.5 parts by mass to 5 parts by mass with respect to the total mass (100 parts by mass) of the support salt and the non-aqueous solvent. Is preferred. When the average particle size of the positive electrode active material is 5 μm or more and less than 7 μm, the cyclic sulfonate content is preferably 0.6 parts by mass or more and 5 parts by mass or less. When the average particle size of the positive electrode active material is 7 μm or more and less than 10 μm, 0.1 mass The cyclic sulfonic acid ester content of not less than 5 parts by mass is preferable. If the cyclic sulfonate content is less than the specified range, film formation is insufficient and the above-mentioned effects can not be obtained. On the other hand, if the amount of cyclic sulfonic acid ester is too large, the film becomes too thick, and the internal resistance of the battery significantly increases, resulting in a decrease in output. By setting the content of the cyclic sulfonic acid ester in the above range, it is possible to secure a certain level of output while achieving long life.
　また、非水溶媒への分解抑制剤として、環状スルホン酸エステルに加えてビニレンカーボネート（VC）を更に含有させることは好ましい。VCは、リチウムイオン二次電池の充電時に負極の表面に薄い被膜を形成し、負極表面での非水溶媒の分解を抑制する効果を有する。VCの含有率は、支持塩と非水溶媒との総質量（100質量部）に対して、0.5質量部以上5質量部以下が好ましい。VCの含有率が、0.5質量部未満だと上記効果が不十分となり、5質量部だと二次電池の充放電時に過剰のVCが分解されて充放電効率が低下する。 Moreover, it is preferable to add vinylene carbonate (VC) in addition to cyclic sulfonic acid ester as a decomposition inhibitor to a non-aqueous solvent. VC forms a thin film on the surface of the negative electrode during charging of the lithium ion secondary battery, and has the effect of suppressing the decomposition of the non-aqueous solvent on the surface of the negative electrode. The content of VC is preferably 0.5 parts by mass or more and 5 parts by mass or less with respect to the total mass (100 parts by mass) of the support salt and the non-aqueous solvent. If the content of VC is less than 0.5 parts by mass, the above effects become insufficient, and if it is 5 parts by mass, excessive VC is decomposed at the time of charge and discharge of the secondary battery, and the charge and discharge efficiency decreases.
　次に、抵抗上昇抑制剤について説明する。本発明では、分解抑制剤による内部抵抗上昇（それにともなう出力低下）を抑制する抵抗上昇抑制剤として、有機リン化合物を添加する。従来、非水電解液への有機リン化合物の添加は、非水電解液に難燃性を付与する目的で行われてきた。一方、それ以外の作用効果は知られていなかった。 Next, the resistance increase inhibitor will be described. In the present invention, an organophosphorus compound is added as a resistance increase inhibitor that suppresses the increase in internal resistance (the output decrease associated therewith) due to the decomposition inhibitor. Heretofore, the addition of the organic phosphorus compound to the non-aqueous electrolyte has been performed for the purpose of imparting the non-aqueous electrolyte with flame retardancy. On the other hand, no other effects were known.
　それに対し、本発明では、分解抑制剤としての環状スルホン酸エステルの添加に加えて、所定の有機リン化合物を追添加することで、環状スルホン酸エステルによる内部抵抗上昇を制御できる効果があることを見出した。これにより環状スルホン酸エステルの分解抑制剤としての機能を維持しつつ、環状スルホン酸エステルによる内部抵抗上昇を抑制することが可能となった。すなわち、本発明おいて、有機リン化合物の添加は内部抵抗上昇の抑制が第一義的な作用効果である。なお、有機リン化合物の添加による難燃性付与の作用効果を否定するものではない。 On the other hand, in the present invention, in addition to the addition of the cyclic sulfonic acid ester as the decomposition inhibitor, by additionally adding a predetermined organic phosphorus compound, there is an effect that the internal resistance increase by the cyclic sulfonic acid ester can be controlled. I found it. It became possible to suppress the internal resistance raise by cyclic sulfonic acid ester, maintaining the function as a decomposition inhibitor of cyclic sulfonic acid ester by this. That is, in the present invention, the addition of the organophosphorus compound is primarily effective in suppressing the increase in internal resistance. The effect of imparting flame retardancy by the addition of the organic phosphorus compound is not denied.
　抵抗上昇抑制剤の作用効果について考察する。前述したように、分解抑制剤による内部抵抗上昇は、電極表面に形成された被膜の抵抗によるものであると考えられる。被膜の電気抵抗は、当然のことながら被膜の密度や分子構造に影響される。分解抑制剤のみを添加した場合は、それ自身と電解液中に含まれる溶媒や電解質に由来する被膜が形成される。これに対し、分解抑制剤と抵抗上昇抑制剤との両方を添加した場合、抵抗上昇抑制剤由来の元素（たとえばリン）が被膜の構成成分として取り込まれることが考えられ、その結果、電解液の分解抑制効果を維持しつつ、被膜の低抵抗化が図れたものと考えられる。 We will consider the effect of resistance rise inhibitor. As described above, the increase in internal resistance by the decomposition inhibitor is considered to be due to the resistance of the film formed on the electrode surface. The electrical resistance of the film is, of course, influenced by the density and molecular structure of the film. When only the decomposition inhibitor is added, a film derived from the solvent and the electrolyte contained in itself and in the electrolytic solution is formed. On the other hand, when both the decomposition inhibitor and the resistance increase inhibitor are added, it is considered that an element (for example, phosphorus) derived from the resistance increase inhibitor is taken in as a component of the film, and as a result, It is considered that the resistance of the film can be reduced while maintaining the decomposition suppressing effect.
　本発明で用いる有機リン化合物としては、下記一般化学式（１）および/または（２）で表される有機リン化合物（ただし、化学式中のR1～R6はそれぞれ一般式CnH2n+1（nは0または正の整数）で表される基である）からなることが好ましい。 The organophosphorus compounds used in the present invention include organophosphorus compounds represented by the following general chemical formula (1) and / or (2) (with the proviso that R 1 to R 6 in the chemical formulas are each represented by the general formula C n H 2n + 1 It is preferable that it consists of (The group represented by n is 0 or a positive integer).
Figure JPOXMLDOC01-appb-C000005
Figure JPOXMLDOC01-appb-C000005
Figure JPOXMLDOC01-appb-C000006
Figure JPOXMLDOC01-appb-C000006
　より具体的には、亜リン酸トリメチル（化学式（１）においてR1～R3がいずれもCH3（すなわちn＝1））、亜リン酸トリエチル（化学式（１）においてR1～R3がいずれもC2H5（すなわちn＝2））、ジメチルメチルホスホナート（化学式（２）においてR4～R6がいずれもCH3）、およびジエチルメチルホスホナート（化学式（２）においてR4がCH3、R5とR6とがC2H5）の内の少なくとも１種が好ましい。 More specifically, trimethyl phosphite (in chemical formula (1), R 1 to R 3 are all CH 3 (ie, n = 1)), triethyl phosphite (in chemical formula (1), R 1 to R 3 is both C 2 H 5 (i.e. n = 2)), R 4 ~ R 6 both are CH 3 in dimethyl methylphosphonate (chemical formula (2)), and R 4 in diethyl methylphosphonate (chemical formula (2) At least one of CH 3 , R 5 and R 6 is preferably C 2 H 5 ).
　これらの有機リン化合物（亜リン酸トリメチル、亜リン酸トリエチル、ジメチルメチルホスホナート、およびジエチルメチルホスホナート）は、他の有機リン化合物と比較すると、エステル結合している基の分子量が小さいことから二次電池の初期の充放電過程において、該結合基が比較的容易に離脱し、リン成分が被膜の構成成分として取り込まれると考えられる。その結果、抵抗上昇抑制剤として高い効果を示すものと考えられる。 These organophosphorus compounds (trimethyl phosphite, triethyl phosphite, dimethyl methyl phosphonate, and diethyl methyl phosphonate) have a smaller molecular weight of the ester-linked group compared to other organophosphorus compounds. In the initial charge and discharge process of the secondary battery, it is considered that the bonding group is relatively easily released and the phosphorus component is incorporated as a component of the film. As a result, it is considered that the agent exhibits a high effect as a resistance increase inhibitor.
　有機リン化合物の含有率は、正極活物質（層状構造を有するリチウムマンガン酸化物）の平均粒径の範囲によって、その最適範囲が変化する。正極活物質の平均粒径が3μm以上5μm未満の場合、支持塩と非水溶媒との総質量（100質量部）に対して、有機リン化合物の含有率は0.2質量部以上5質量部以下が好ましい。正極活物質の平均粒径が5μm以上7μm未満の場合は0.1質量部以上9質量部以下の有機リン化合物含有率が好ましく、正極活物質の粒径が7μm以上10μm未満の場合は0.1質量部以上11質量部以下の有機リン化合物含有率が好ましい。有機リン化合物の含有率が少ないと抵抗上昇抑制の効果が不十分となり、多過ぎると有機リン化合物の分解に由来する寿命の低下が顕著になる。有機リン化合物の含有率を当該範囲とし、かつ、環状スルホン酸エステルと組み合わせて添加することにより、リチウムイオン二次電池の容量や寿命への負の影響を最小限にとどめながら、高出力化を果たすことが可能となる。 The optimum range of the content of the organic phosphorus compound changes depending on the range of the average particle diameter of the positive electrode active material (lithium manganese oxide having a layered structure). When the average particle diameter of the positive electrode active material is 3 μm or more and less than 5 μm, the content of the organic phosphorus compound is 0.2 parts by mass or more and 5 parts by mass or less with respect to the total mass (100 parts by mass) of the support salt and the non-aqueous solvent preferable. When the average particle diameter of the positive electrode active material is 5 μm or more and less than 7 μm, the organic phosphorus compound content is preferably 0.1 parts by mass to 9 parts by mass, and when the particle diameter of the positive electrode active material is 7 μm or more and less than 10 μm, 0.1 parts by mass or more An organophosphorus compound content of 11 parts by mass or less is preferred. When the content of the organic phosphorus compound is low, the effect of suppressing the increase in resistance is insufficient, and when the content is too high, the decrease in the life due to the decomposition of the organic phosphorus compound becomes remarkable. By setting the content of the organic phosphorus compound in the relevant range and adding it in combination with the cyclic sulfonic acid ester, high output can be achieved while minimizing the negative influence on the capacity and life of the lithium ion secondary battery. It can be done.
　次に、非水電解液の支持塩（電解質とも言う）について説明する。非水電解液に用いる支持塩としては、例えば、LiPF6、LiBF4、LiClO4、LiCF3SO3、LiCF3CO2、LiAsF6、LiSbF6、LiCF3SO3、LiN(SO2CF3)2のいずれかの単体または混合物を好適に用いることができる。その中でも、LiPF6がより好ましい。LiPF6は、高伝導度が得られることから、支持塩の中でも高い出力性能を得ることができる。 Next, a supporting salt (also referred to as an electrolyte) of the non-aqueous electrolytic solution will be described. As the supporting salt used in the non-aqueous electrolyte solution, for example, LiPF 6, LiBF 4, LiClO 4, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF 6, LiSbF 6, LiCF 3 SO 3, LiN (SO 2 CF 3) Any one or a mixture of the two can be suitably used. Among them, LiPF 6 is more preferable. LiPF 6 can achieve high output performance among support salts because high conductivity can be obtained.
　（リチウムイオン二次電池）
　リチウムイオン二次電池の構成について説明する。図１は、本発明に係るリチウムイオン二次電池の一例を示す断面模式図である。本発明に係るリチウムイオン二次電池101において、正極107および負極108は、これらが直接接触しないようにセパレータ109を挟み込んだ状態で積層されて、電極群を形成している。最も外側のセパレータ109は、電極群と電池容器102の間を絶縁している。なお、電極群の構造は、それに限定されるものではなく、例えば、円筒状や扁平状に電極群を捲回したものであってもよい。 (Lithium ion secondary battery)
The configuration of the lithium ion secondary battery will be described. FIG. 1 is a schematic cross-sectional view showing an example of a lithium ion secondary battery according to the present invention. In the lithium ion secondary battery 101 according to the present invention, the positive electrode 107 and the negative electrode 108 are stacked in a state of sandwiching the separator 109 so as not to make direct contact with each other to form an electrode group. The outermost separator 109 insulates between the electrode assembly and the battery case 102. In addition, the structure of an electrode group is not limited to it, For example, what wound the electrode group in cylindrical shape or flat shape may be used.
　正極107には正極リード110が付設されており、負極108には負極リード111が付設されている。リード110，111は、ワイヤ状、箔状、板状などの任意の形状を採ることができる。電気的損失を小さくし、かつ化学的安定性を確保できるような構造・材質が選定される。 The positive electrode lead 110 is attached to the positive electrode 107, and the negative electrode lead 111 is attached to the negative electrode 108. The leads 110 and 111 can have any shape such as a wire shape, a foil shape, or a plate shape. The structure and material are selected so as to reduce the electrical loss and secure the chemical stability.
　電極群は、電池容器102に収容されており、電池容器102の上部に設置された電池蓋103によって密封されている。電池蓋103には、絶縁シール112を介して、正極外部端子104と負極外部端子105が設けられている。さらに、電池容器102の内部には、前述した本発明に係る非水電解液（図示せず）が注入されている。電極群を電池容器102に収納し密閉した後に、本発明に係る非水電解液を注液口106より滴下し、所定量の充填した後に、注液口106を密封する。なお、非水電解液の注入方法・手順は、他の方法・手順でもよい。 The electrode group is accommodated in the battery case 102 and is sealed by a battery cover 103 disposed on the top of the battery case 102. The battery cover 103 is provided with the positive electrode external terminal 104 and the negative electrode external terminal 105 via the insulating seal 112. Furthermore, the non-aqueous electrolytic solution (not shown) according to the present invention described above is injected into the inside of the battery container 102. After the electrode group is housed and sealed in the battery container 102, the non-aqueous electrolyte according to the present invention is dropped from the liquid injection port 106, and after filling a predetermined amount, the liquid injection port 106 is sealed. The non-aqueous electrolyte injection method / procedure may be another method / procedure.
　電池容器102の形状は、通常、電極群の形状に合わせた形状（例えば、円筒状、扁平長円柱状、角柱など）が選択される。絶縁性シール112は、非水電解液と反応せず、かつ気密性に優れた任意の材質（例えば、熱硬化性樹脂、ガラスハーメチックシールなど）を好適に使用することができる。 For the shape of the battery container 102, a shape (for example, a cylindrical shape, a flat long cylindrical shape, a prism, etc.) that is matched to the shape of the electrode group is usually selected. As the insulating seal 112, any material (for example, a thermosetting resin, a glass hermetic seal, etc.) which does not react with the non-aqueous electrolytic solution and is excellent in airtightness can be suitably used.
　電池容器102の材質は、アルミニウム、ステンレス鋼、ニッケルメッキ鋼製など、非水電解液に対して耐食性のある材料から選択される。電池容器102への蓋103の取り付けは、溶接の他に、かしめ、接着などの他の方法も採ることができる。非水電解液の注液に用いる注液口106に安全機構としての機能を付与することも可能である。安全機構としては、例えば、電池容器内部の圧力が所定以上となった際に解放する圧力弁がある。 The material of the battery case 102 is selected from materials having corrosion resistance to the non-aqueous electrolyte, such as aluminum, stainless steel, nickel plated steel, and the like. The attachment of the lid 103 to the battery case 102 can be performed by other methods such as caulking, adhesion, etc. in addition to welding. It is also possible to impart a function as a safety mechanism to the injection port 106 used for injection of the non-aqueous electrolyte. As a safety mechanism, there is, for example, a pressure valve which is released when the pressure inside the battery container becomes a predetermined value or more.
　正極リード110または負極リード111の途中、あるいは正極リード110と正極外部端子104との接続部や、負極リード111と負極外部端子105との接続部に、正温度係数抵抗素子を利用した電流遮断機構（図示せず）を設けることは好ましい。電流遮断機構を設けると、電池内部の温度が高くなったときに、リチウムイオン二次電池101の充放電を停止させ、電池を保護することが可能となる。 A current interrupting mechanism using a positive temperature coefficient resistance element in the middle of the positive electrode lead 110 or the negative electrode lead 111 or at the connection portion between the positive electrode lead 110 and the positive electrode external terminal 104 or at the connection portion between the negative electrode lead 111 and the negative electrode external terminal 105 It is preferable to provide (not shown). When the current interrupting mechanism is provided, charging and discharging of the lithium ion secondary battery 101 can be stopped and the battery can be protected when the temperature inside the battery rises.
　リチウムイオン二次電池を構成する正極107は、正極集電体の片面または両面に正極活物質を含む正極合剤スラリーを塗布・乾燥させた後、ロールプレス機などを用いて圧縮成形して、所定の大きさに切断することで作製される。正極の集電体には、厚さが10～100μmのアルミニウム箔や、厚さ10～100μmで孔径0.1～10 mmのアルミニウム製穿孔箔、エキスパンドメタル、発泡アルミニウム板などが用いられる。材質は、アルミニウムの他に、ステンレス、チタンなども適用可能である。 The positive electrode 107 constituting the lithium ion secondary battery is formed by applying and drying a positive electrode mixture slurry containing a positive electrode active material on one side or both sides of a positive electrode current collector, and compression molding using a roll press machine, etc. It is produced by cutting into a predetermined size. For the current collector of the positive electrode, an aluminum foil having a thickness of 10 to 100 μm, a perforated foil made of aluminum having a thickness of 10 to 100 μm and a hole diameter of 0.1 to 10 mm, an expanded metal, a foam aluminum plate or the like is used. In addition to aluminum, stainless steel, titanium, etc. can be applied as the material.
　同様に、リチウムイオン二次電池を構成する負極108は、負極集電体の片面または両面に負極活物質を含む負極合剤スラリーを塗布・乾燥させた後、ロールプレス機などを用いて圧縮成形して、所定の大きさに切断することで作製される。負極の集電体には、厚さが10～100μmの銅箔や、厚さ10～100μmで孔径0.1～10mmの銅製穿孔箔、エキスパンドメタル、発泡銅板などが用いられ、材質は、銅の他に、ステンレス、チタン、ニッケルなども適用可能である。 Similarly, the negative electrode 108 constituting the lithium ion secondary battery is formed by applying and drying a negative electrode mixture slurry containing the negative electrode active material on one side or both sides of the negative electrode current collector, and then compression molding using a roll press machine or the like. Then, it is manufactured by cutting into a predetermined size. For the current collector of the negative electrode, a copper foil having a thickness of 10 to 100 μm, a perforated copper foil having a thickness of 10 to 100 μm and a hole diameter of 0.1 to 10 mm, an expanded metal, a foamed copper plate, etc. are used. In addition, stainless steel, titanium, nickel and the like are also applicable.
　正極合剤スラリーおよび負極合剤スラリーの塗布方法に特段の限定はなく、従前の方法（例えば、ドクターブレード法、ディッピング法、スプレー法など）を利用することができる。また、塗布から乾燥までを複数回行うことにより、複数の合剤層を集電体に積層することも可能である。 There is no particular limitation on the method of applying the positive electrode mixture slurry and the negative electrode mixture slurry, and a conventional method (for example, a doctor blade method, a dipping method, a spray method, etc.) can be used. Moreover, it is also possible to laminate a plurality of mixture layers on the current collector by performing a plurality of times from application to drying.
　正極107に用いられる正極活物質としては、前述した本発明の正極活物質を用いる。正極活物質に対して、バインダ、増粘剤、導電材、溶媒等を必要に応じて混合して正極合剤スラリーが作製される。 As a positive electrode active material used for the positive electrode 107, the above-mentioned positive electrode active material of the present invention is used. A binder, a thickener, a conductive material, a solvent, and the like are mixed with the positive electrode active material as necessary to prepare a positive electrode mixture slurry.
　正極活物質は、その平均粒径dAが「3μm≦dA＜10μm」となるように調整される。より具体的には、「3μm≦dA＜5μm」、「5μm≦dA＜7μm」、および「7μm≦dA＜10μm」のいずれの範囲に分類されるかを管理することが好ましい。また、最大粒径が合剤層の厚さ以下になるように調整される。正極活物質粉末中に規定外の粒子がある場合、粉末粒度を規定内に調整するため、従前の方法（例えば、ふるい分級、風流分級など）により規定外の微細粒や粗粒を除去する。 The positive electrode active material is adjusted such that the average particle size d A is “3 μm ≦ d A <10 μm”. More specifically, it is preferable to manage which of “3 μm ≦ d A <5 μm”, “5 μm ≦ d A <7 μm”, and “7 μm ≦ d A <10 μm”. Also, the maximum particle size is adjusted to be equal to or less than the thickness of the mixture layer. When there are non-specified particles in the positive electrode active material powder, in order to adjust the powder particle size within the specified range, the non-specified fine particles and coarse particles are removed by a conventional method (for example, sieve classification, air flow classification, etc.).
　正極活物質とバインダとの混合比率は、質量比で85 : 15～95 : 5の範囲になるようにすることが好ましい。正極活物質の質量比率が85/100未満では、活物質量が少ないため、充放電可能な容量が低下し、二次電池のエネルギー密度が低下する。一方、正極活物質の質量比率が95/100超では、活物質間、活物質-導電材間の密着力が低下し、接触抵抗が大きくなるため、出力が低下する。 The mixing ratio of the positive electrode active material to the binder is preferably in the range of 85:15 to 95: 5 by mass. If the mass ratio of the positive electrode active material is less than 85/100, since the amount of active material is small, the chargeable / dischargeable capacity decreases and the energy density of the secondary battery decreases. On the other hand, if the mass ratio of the positive electrode active material is more than 95/100, the adhesion between the active material and the active material and the conductive material is reduced, and the contact resistance is increased, so that the output is reduced.
　正極の導電材としては、導電性繊維（例えば、気相成長炭素、カーボンナノチューブ、ピッチ（石油、石炭、コールタールなどの副生成物）を原料に高温で炭化して製造した繊維、アクリル繊維から製造した炭素繊維など）が好適に用いられる。また、導電材は、正極活物質よりも電気抵抗の低い材料であって、正極の充放電電位（通常は2.5～4.2Vである）にて酸化溶解しない材料を使用してもよい。例えば、耐食性金属（チタンや金など）、炭化物（SiCやWCなど）、窒化物（Si3N4やBNなど）が挙げられる。高比表面積の炭素材料（例えば、カーボンブラックや活性炭など）も使用できる。 As the conductive material of the positive electrode, fibers produced by carbonizing conductive fibers (for example, vapor grown carbon, carbon nanotubes, pitch (petroleum, coal, coal tar, etc. by-products) at a high temperature at a high temperature, acrylic fibers The carbon fiber etc. which were manufactured are used suitably. In addition, the conductive material may be a material having lower electrical resistance than the positive electrode active material, and a material that does not dissolve by oxidation at the charge / discharge potential of the positive electrode (usually 2.5 to 4.2 V). Examples include corrosion-resistant metals (such as titanium and gold), carbides (such as SiC and WC), and nitrides (such as Si 3 N 4 and BN). High specific surface area carbon materials such as carbon black and activated carbon can also be used.
　負極108に用いられる負極活物質は、リチウムイオンの吸蔵および放出をすることができる材料であれば特に限定されない。例えば、アルミニウム、シリコン、錫、炭素材料（例えば、黒鉛、易黒鉛化炭素、難黒鉛化炭素天然黒鉛、人造黒鉛、メソフェ－ズ炭素、膨張黒鉛、炭素繊維、気相成長法炭素繊維、ピッチ系炭素質材料、ニードルコークス、石油コークス、ポリアクリロニトリル系炭素繊維、カーボンブラック、非晶質炭素）、酸化物（例えば、チタン酸リチウム、酸化チタン、酸化鉄、酸化バナジウム、酸化アンチモン）が利用可能である。非晶質炭素は、例えば、５員環または６員環の環式炭化水素や環式含酸素有機化合物を熱分解して作製される。これらいずれかの単独または２種以上の混合物を用いることができる。これらの中でも、炭素材料はリチウムイオンの吸蔵および放出の際の体積変化率が少ない材料であるため、充放電による劣化が少ない（長寿命）であることから、負極活物質として非晶質炭素を含むことは好ましい。また、上述した炭素材料に加えて、導電性高分子材料（ポリアセン、ポリパラフェニレン、ポリアニリン、ポリアセチレンなど）を添加してもよい。負極活物質に対して、バインダ、増粘剤、導電材、溶媒等を必要に応じて混合して負極合剤スラリーが作製される。 The negative electrode active material used for the negative electrode 108 is not particularly limited as long as it is a material capable of absorbing and releasing lithium ions. For example, aluminum, silicon, tin, carbon materials (eg, graphite, graphitizable carbon, non-graphitizable carbon natural graphite, artificial graphite, mesophase carbon, expanded graphite, carbon fiber, vapor grown carbon fiber, pitch-based Carbonaceous materials, needle coke, petroleum coke, polyacrylonitrile carbon fiber, carbon black, amorphous carbon, oxides (eg, lithium titanate, titanium oxide, iron oxide, vanadium oxide, antimony oxide) are available. is there. Amorphous carbon is produced, for example, by thermal decomposition of a 5- or 6-membered cyclic hydrocarbon or a cyclic oxygen-containing organic compound. Any one of these or a mixture of two or more can be used. Among these, carbon materials are materials having a small volume change rate at the time of insertion and extraction of lithium ions, and therefore, deterioration due to charge and discharge is small (long life), so amorphous carbon is used as a negative electrode active material. It is preferable to include. In addition to the above-mentioned carbon materials, conductive polymer materials (polyacene, polyparaphenylene, polyaniline, polyacetylene, etc.) may be added. A binder, a thickener, a conductive material, a solvent, and the like are mixed as needed with the negative electrode active material to prepare a negative electrode mixture slurry.
　負極活物質とバインダの混合比率は、質量比で90 : 10～99 : 1の範囲になるようにすることが好ましい。負極活物質の質量比率が90/100未満では、活物質量が少ないため、充放電可能な容量が低下し、二次電池のエネルギー密度が低下する。一方、負極活物質の質量比率が99/100超では、活物質間、活物質-導電材間の密着力が低下し、接触抵抗が大きくなるため、出力が低下する。負極の導電材としては、正極導電材と同様の材料を用いることが可能である。 The mixing ratio of the negative electrode active material to the binder is preferably in the range of 90:10 to 99: 1 by mass. If the mass ratio of the negative electrode active material is less than 90/100, since the amount of active material is small, the chargeable / dischargeable capacity decreases and the energy density of the secondary battery decreases. On the other hand, when the mass ratio of the negative electrode active material is over 99/100, the adhesion between the active material and between the active material and the conductive material is lowered, and the contact resistance is increased, whereby the output is lowered. As the conductive material of the negative electrode, it is possible to use the same material as the positive electrode conductive material.
　正極合剤スラリーおよび負極合剤スラリーに用いられるバインダ、増粘剤および溶媒に特段の限定はなく、従前と同様のものを用いることができる。 There is no particular limitation on the binder, the thickener and the solvent used for the positive electrode mixture slurry and the negative electrode mixture slurry, and the same ones as before can be used.
　セパレータ109は、二次電池の充放電時にリチウムイオンを透過させる必要があるため、多孔体（例えば、細孔径が0.01～10μm、気孔率が20～90％）であることが好ましい。セパレータ109の素材としては、ポリオレフィン系高分子シート（例えば、ポリエチレンやポリプロピレンなど）や、ポリオレフィン系高分子シートとフッ素系高分子シート（例えば、四フッ化ポリエチレン）とを溶着させた多層構造シートを好適に使用できる。また、セパレータ109の表面にセラミックスとバインダの混合物を薄層状に形成しても良い。 The separator 109 is preferably a porous body (for example, with a pore diameter of 0.01 to 10 μm and a porosity of 20 to 90%) because lithium ions need to be transmitted during charge and discharge of the secondary battery. As a material of the separator 109, a multilayer structure sheet in which a polyolefin-based polymer sheet (for example, polyethylene, polypropylene and the like) or a polyolefin-based polymer sheet and a fluorine-based polymer sheet (for example, polytetrafluoroethylene) are welded It can be used suitably. Alternatively, a mixture of ceramics and a binder may be formed in a thin layer on the surface of the separator 109.
　電解質として、固体高分子電解質（ポリマー電解質）を用いる場合には、エチレンオキシド、アクリロニトリル、ポリフッ化ビニリデン、メタクリル酸メチル、ヘキサフルオロプロピレンのポリエチレンオキサイドなどのイオン導電性ポリマーを好適に用いることができる。これらの固体高分子電解質を用いた場合、セパレータ109を省略することができる。 When a solid polymer electrolyte (polymer electrolyte) is used as the electrolyte, an ion conductive polymer such as ethylene oxide, acrylonitrile, polyvinylidene fluoride, methyl methacrylate or polyethylene oxide of hexafluoropropylene can be suitably used. When these solid polymer electrolytes are used, the separator 109 can be omitted.
　本発明に係るリチウムイオン二次電池は、前述した正極活物質と非水電解液とを用いていることから、容量、出力および寿命の３項目を高いレベルでバランスさせたリチウムイオン二次電池を提供することができる。電池性能の具体的な事例については、後述する。 Since the lithium ion secondary battery according to the present invention uses the above-described positive electrode active material and the non-aqueous electrolyte solution, a lithium ion secondary battery in which three items of capacity, output and life are balanced at a high level Can be provided. Specific examples of battery performance will be described later.
　［二次電池システム］
　リチウムイオン二次電池を用いた二次電池システムの構成について説明する。本発明に係る二次電池システムとは、少なくとも２個のリチウムイオン二次電池を直列あるいは並列に接続し、かつ充放電制御機構を有するシステムと定義する。図２は、本発明に係る二次電池システムの一例を示す断面模式図である。図２に示したように、本構成では２個のリチウムイオン二次電池101a，101bが直列に接続されている。図２の紙面右側に配置したリチウムイオン二次電池101aの負極外部端子105は、電力ケーブル213により充放電制御機構216の負極入力ターミナルに接続されている。リチウムイオン二次電池101aの正極外部端子104は、電力ケーブル214によりリチウムイオン二次電池101bの負極外部端子105に接続されている。さらに、リチウムイオン二次電池101bの正極外部端子104は、電力ケーブル215により充放電制御機構216の正極入力ターミナルに接続されている。このような配線構成によって、2個のリチウムイオン二次電池101a，101bを充放電制御機構216で制御しながら充電または放電させることができる。なお、図１，図２において、同じ構成物には同じ符号を付している。 [Secondary battery system]
The configuration of a secondary battery system using a lithium ion secondary battery will be described. The secondary battery system according to the present invention is defined as a system having at least two lithium ion secondary batteries connected in series or in parallel and having a charge / discharge control mechanism. FIG. 2 is a schematic cross-sectional view showing an example of a secondary battery system according to the present invention. As shown in FIG. 2, in this configuration, two lithium ion secondary batteries 101 a and 101 b are connected in series. The negative electrode external terminal 105 of the lithium ion secondary battery 101 a disposed on the right side of the drawing of FIG. 2 is connected to the negative electrode input terminal of the charge / discharge control mechanism 216 by the power cable 213. The positive electrode external terminal 104 of the lithium ion secondary battery 101 a is connected to the negative electrode external terminal 105 of the lithium ion secondary battery 101 b by a power cable 214. Furthermore, the positive electrode external terminal 104 of the lithium ion secondary battery 101 b is connected to the positive electrode input terminal of the charge / discharge control mechanism 216 by the power cable 215. With such a wiring configuration, the two lithium ion secondary batteries 101 a and 101 b can be charged or discharged while being controlled by the charge / discharge control mechanism 216. In FIGS. 1 and 2, the same components are denoted by the same reference numerals.
　充放電制御機構216は、電力ケーブル217，218を介して、外部機器219との間で電力の授受を行う。外部機器219は、外部負荷の他、充放電制御機構216に給電するための外部電源や回生モータ等の各種電気機器を含む。また、外部機器が対応する交流、直流の種類に応じて、インバータやコンバータを設けることができる。 The charge / discharge control mechanism 216 exchanges power with the external device 219 via the power cables 217 and 218. The external device 219 includes various external devices such as an external power source for supplying power to the charge and discharge control mechanism 216 and a regenerative motor, in addition to the external load. In addition, an inverter or a converter can be provided according to the type of alternating current or direct current to which the external device corresponds.
　発電装置222が、電力ケーブル220，221を介して充放電制御機構216に接続される。発電装置222が発電しているときには、充放電制御機構216が充電モードに移行し、外部機器219に給電するとともに、余剰電力をリチウムイオン二次電池101a，101bに充電する。発電装置222の発電量が外部機器219の要求電力よりも少ないときには、リチウムイオン二次電池101a，101bから電力供給させるように充放電制御機構216が放電モードに移行する。充放電制御機構216は、そのようなモード移行が自動的に行われるようにプログラムが記憶されていることが好ましい。 The power generation device 222 is connected to the charge and discharge control mechanism 216 via the power cables 220 and 221. When the power generation device 222 is generating power, the charge / discharge control mechanism 216 shifts to the charge mode to feed power to the external device 219 and charge the lithium ion secondary batteries 101a and 101b with surplus power. When the power generation amount of the power generation device 222 is smaller than the required power of the external device 219, the charge / discharge control mechanism 216 shifts to the discharge mode so as to supply power from the lithium ion secondary batteries 101a and 101b. The charge / discharge control mechanism 216 preferably stores a program so that such mode transition is automatically performed.
　発電装置222としては、再生可能エネルギーを生み出す発電装置（例えば、風力発電装置、地熱発電装置、太陽電池）や、通常の発電装置（例えば、燃料電池、ガスタービン発電機など）を用いることができる。 As the power generation device 222, a power generation device (for example, a wind power generation device, a geothermal power generation device, a solar cell) that produces renewable energy, or a normal power generation device (for example, a fuel cell, a gas turbine generator, etc.) can be used. .
　本発明に係る二次電池システムは、例えば、電気自動車、ハイブリッド電気自動車、プラグインハイブリッド電気自動車、電動式建設機械、運搬機器、建設機械、介護機器、軽車両、電動工具、ロボット、離島の電力貯蔵システム、宇宙ステーションなどの電源として利用することができる。 The secondary battery system according to the present invention includes, for example, electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric construction machines, transport equipment, construction machines, nursing care equipment, light vehicles, electric tools, robots, island electric power. It can be used as a power supply for storage systems, space stations, etc.
　本発明は、リチウムイオン電池に限らず、非水電解液を用い、電極へのイオンの吸蔵・放出により、電気エネルギーを貯蔵・利用可能とする電気化学デバイスに適用することが可能である。本発明は出力に優れるため、特に大型の移動体用途に好適である。 The present invention is not limited to lithium ion batteries, and can be applied to electrochemical devices that can store and utilize electrical energy by using non-aqueous electrolytes and absorbing and releasing ions to electrodes. Since the present invention is excellent in output, it is particularly suitable for large mobile applications.
　以下、実施例および比較例により本発明をさらに具体的に説明する。なお、本発明はこれらの実施例に限定されるものではない。 Hereinafter, the present invention will be more specifically described by way of examples and comparative examples. The present invention is not limited to these examples.
　［実験１］
　（実施例１，２のリチウムイオン二次電池の作製）
　（１）正極の作製
　まず、正極活物質（86質量％）、導電材（7質量％、黒鉛とカーボンブラックとの混合物）、バインダ（7質量％、ポリフッ化ビニリデン（PVDF）、株式会社クレハ製）および溶媒（1-メチル-2-ピロリドン）を調合して正極合剤スラリーを作製した。正極活物質としては、層状構造を有するリチウムマンガン酸化物（平均粒径8μm）を用意した。 [Experiment 1]
(Production of Lithium Ion Secondary Battery of Examples 1 and 2)
(1) Production of Positive Electrode First, a positive electrode active material (86 mass%), a conductive material (7 mass%, a mixture of graphite and carbon black), a binder (7 mass%, polyvinylidene fluoride (PVDF), manufactured by Kureha Co., Ltd. And a solvent (1-methyl-2-pyrrolidone) were prepared to prepare a positive electrode mixture slurry. As a positive electrode active material, lithium manganese oxide (average particle diameter 8 μm) having a layered structure was prepared.
　次に、この正極合剤スラリーを、厚さ15μmの正極集電体（アルミニウム箔）の片面にドクターブレード法を用いて塗布し、乾燥させて、正極合剤層を形成した。その後、ロールプレス機により圧縮成形し、所定の大きさに切断してリチウムイオン二次電池用正極を作製した。 Next, this positive electrode mixture slurry was applied onto one side of a 15 μm-thick positive electrode current collector (aluminum foil) using a doctor blade method, and dried to form a positive electrode mixture layer. Then, it compression-molded by the roll press machine, it cut | disconnected to a predetermined | prescribed size, and produced the positive electrode for lithium ion secondary batteries.
　なお、前述したように、本発明におけるリチウムマンガン酸化物の平均粒径とは、正極を表面または断面の顕微鏡観察による像に対して画像解析を行って求めたものである。ここでは、次のような手順で平均粒径を評価した。まず、二次電池用の正極と同時に評価用の正極試料を作製も併せて作製した。走査型電子顕微鏡（株式会社日立製作所製、型式S-4300）を用いて、得られた評価用正極の断面を観察し、画像を取得した。取得した画像内の正極活物質の各粒子に対して、画像解析により、該粒子の面積と等価面積になる円（等価円）の直径を求め、その平均値を平均粒径とした。 As described above, the average particle diameter of the lithium manganese oxide in the present invention is determined by performing image analysis on an image obtained by microscopic observation of the surface or cross section of the positive electrode. Here, the average particle size was evaluated by the following procedure. First, a positive electrode sample for evaluation was also manufactured together with a positive electrode for a secondary battery. The cross section of the obtained evaluation positive electrode was observed using a scanning electron microscope (Model S-4300, manufactured by Hitachi, Ltd.) to obtain an image. For each particle of the positive electrode active material in the acquired image, the diameter of a circle (equivalent circle) equivalent to the area of the particle is determined by image analysis, and the average value is taken as the average particle diameter.
　（２）負極の作製
　負極活物質（91質量％、非晶質炭素）、バインダ（2質量％、ポリフッ化ビニリデン（PVDF）、株式会社クレハ製）、導電材（7質量％、カーボンブラック）および溶媒（1-メチル-2-ピロリドン）を調合して負極合剤スラリーを作製した。 (2) Preparation of Negative Electrode Negative electrode active material (91% by mass, amorphous carbon), binder (2% by mass, polyvinylidene fluoride (PVDF), manufactured by Kureha Co., Ltd.), conductive material (7% by mass, carbon black) A solvent (1-methyl-2-pyrrolidone) was prepared to prepare a negative electrode mixture slurry.
　次に、この負極合剤スラリーを、厚さ10μmの負極集電体（銅箔）の片面にドクターブレード法を用いて塗布し、乾燥させて、負極合剤層を形成した。その後、ロールプレス機により圧縮成形し、所定の大きさに切断してリチウムイオン二次電池用負極を作製した。 Next, this negative electrode mixture slurry was applied onto one side of a negative electrode current collector (copper foil) with a thickness of 10 μm using a doctor blade method, and dried to form a negative electrode mixture layer. Then, it compression-molded by the roll press machine, it cut | disconnected to a predetermined | prescribed size, and produced the negative electrode for lithium ion secondary batteries.
　（３）非水電解液の作製
　非水電解液は、次のような手順で用意した。はじめに、非水溶媒は、エチレンカーボネート（EC）とエチルメチルカーボネート（EMC）とを用い、ECとEMCとの体積比が1：2となるように混合した。該非水溶媒に対して、支持塩として六フッ化リン酸リチウム（LiPF6）を1 mol/Lとなるように溶解させた。次に、該支持塩溶液（支持塩を溶解させた非水溶媒）100質量部に対して、分解抑制剤として0.1質量部または5質量部の1,3-プロペンスルトン（PRS）と1質量部のビニレンカーボネート（VC）とを添加し、抵抗上昇抑制剤として0.1質量部または11質量部の亜リン酸トリメチル（TMPI）を添加して非水電解液（実施例１，２）を作製した。 (3) Preparation of Nonaqueous Electrolyte Nonaqueous electrolyte was prepared by the following procedure. First, the non-aqueous solvent was mixed using ethylene carbonate (EC) and ethyl methyl carbonate (EMC) such that the volume ratio of EC to EMC was 1: 2. In the non-aqueous solvent, lithium hexafluorophosphate (LiPF 6 ) was dissolved to a concentration of 1 mol / L as a supporting salt. Next, 0.1 parts by mass or 5 parts by mass of 1,3-propene sultone (PRS) and 1 part by mass as a decomposition inhibitor with respect to 100 parts by mass of the supporting salt solution (nonaqueous solvent in which the supporting salt is dissolved) The vinylene carbonate (VC) of the above was added, and 0.1 parts by mass or 11 parts by mass of trimethyl phosphite (TMPI) was added as a resistance increase inhibitor to prepare non-aqueous electrolytes (Examples 1 and 2).
　なお、実施例および比較例における、正極活物質の平均粒径および非水電解液添加剤の混合比率の一覧を後述する表１～３に示す。また、上述したように、支持塩の濃度は非水溶媒におけるモル濃度であり、分解抑制剤および抵抗上昇抑制剤の濃度は支持塩溶液100質量部に対する質量部である（以下、同様）。 A list of the average particle diameter of the positive electrode active material and the mixing ratio of the non-aqueous electrolytic solution additive in Examples and Comparative Examples is shown in Tables 1 to 3 described later. As described above, the concentration of the support salt is the molar concentration in the non-aqueous solvent, and the concentrations of the decomposition inhibitor and the resistance increase inhibitor are parts by mass with respect to 100 parts by mass of the support salt solution (the same applies hereinafter).
　（４）リチウムイオン二次電池の作製
　上記で作製した正極、負極および非水電解液を使用して、図１に示したリチウムイオン二次電池を作製した。電池容器102および蓋103にはステンレス鋼を用い、セパレータ109には厚さ30μmの多孔性のポリエチレンフィルムを用い、絶縁性シール112にはフッ素樹脂を用いた。また、図１に示したように、セパレータ109は、正極107と電池容器102との間、負極108と電池容器102との間にも配置し、電池容器102を通じて正極107と負極108とが短絡しない構成とした。 (4) Preparation of Lithium Ion Secondary Battery Using the positive electrode, the negative electrode, and the non-aqueous electrolyte prepared above, a lithium ion secondary battery shown in FIG. 1 was prepared. Stainless steel was used for the battery container 102 and the lid 103, a porous polyethylene film with a thickness of 30 μm was used for the separator 109, and a fluorine resin was used for the insulating seal 112. Further, as shown in FIG. 1, the separator 109 is also disposed between the positive electrode 107 and the battery case 102 and between the negative electrode 108 and the battery case 102, and the positive electrode 107 and the negative electrode 108 are shorted through the battery case 102. It was not configured.
　（実施例３のリチウムイオン二次電池の作製）
　分解抑制剤として2質量部のプロパンスルトン（PS）と1質量部のVCとを添加し、抵抗上昇抑制剤として3質量部のTMPIを添加したこと以外は実施例１と同様にして、実施例３のリチウムイオンニ次電池を作製した。 (Production of Lithium Ion Secondary Battery of Example 3)
Example 1 in the same manner as Example 1, except that 2 parts by mass of propane sultone (PS) and 1 part by mass of VC were added as decomposition inhibitors, and 3 parts by mass of TMPI as a resistance increase inhibitor. Three lithium ion secondary batteries were produced.
　（実施例４～６のリチウムイオン二次電池の作製）
　抵抗上昇抑制剤として3質量部の亜リン酸トリエチル（TEPI）、5質量部のジメチルメチルホスホナート（DMMP）、または3質量部のジエチルメチルホスホナート（DEMP）を添加したこと以外は実施例１と同様にして、実施例４～６のリチウムイオンニ次電池を作製した。実施例４～６は、主に抵抗上昇抑制剤が実施例１と異なる例である。 (Fabrication of lithium ion secondary battery of Examples 4 to 6)
Example 1 except that 3 parts by mass of triethyl phosphite (TEPI), 5 parts by mass of dimethyl methyl phosphonate (DMMP), or 3 parts by mass of diethyl methyl phosphonate (DEMP) were added as a resistance increase inhibitor. The lithium ion secondary batteries of Examples 4 to 6 were produced in the same manner as in the above. Examples 4 to 6 are mainly examples in which the resistance increase inhibitor is different from Example 1.
　（実施例７～９のリチウムイオン二次電池の作製）
　分解抑制剤として2質量部のPRSと0～2質量部のVCとを添加し、抵抗上昇抑制剤として3質量部のTMPIを添加して非水電解液を作製したこと以外は実施例１と同様にして、実施例７～９のリチウムイオンニ次電池を作製した。実施例７～９は、VC（ビニレンカーボネート）の影響を確認する例である。 (Fabrication of lithium ion secondary battery of Examples 7 to 9)
Example 1 and Example 1 were prepared except that 2 parts by mass of PRS and 0 to 2 parts by mass of VC were added as decomposition inhibitors, and 3 parts by mass of TMPI were added as resistance increase inhibitors. Similarly, lithium ion secondary batteries of Examples 7 to 9 were produced. Examples 7 to 9 are examples for confirming the influence of VC (vinylene carbonate).
　（実施例１０，１１のリチウムイオン二次電池の作製）
　非水溶媒としてエチレンカーボネート（EC）とジメチルカーボネート（DMC）とが1：2の体積比で混合された非水溶媒を用いたこと以外は実施例８と同様にして、実施例１０のリチウムイオンニ次電池を作製した。一方、支持塩として四フッ化ほう酸リチウム（LiBF4）を用いたこと以外は実施例８と同様にして、実施例１１のリチウムイオンニ次電池を作製した。なお、実施例１０，１１は、表１に記載していない非水溶媒や支持塩の変更例となっている（言い換えると、表１中では、実施例８と同じ表記になっている）。 (Production of Lithium Ion Secondary Battery of Examples 10 and 11)
A lithium ion polymer of Example 10 was prepared in the same manner as Example 8, except that a non-aqueous solvent in which ethylene carbonate (EC) and dimethyl carbonate (DMC) were mixed at a volume ratio of 1: 2 was used as the non-aqueous solvent. The following battery was produced. On the other hand, a lithium ion secondary battery of Example 11 was produced in the same manner as in Example 8 except that lithium tetrafluoroborate (LiBF 4 ) was used as a supporting salt. Examples 10 and 11 are modifications of the non-aqueous solvent and the supporting salt which are not described in Table 1 (in other words, in Table 1, the same notation as in Example 8).
　（実施例１２，１３のリチウムイオン二次電池の作製）
　正極活物質として平均粒径が6μmの層状構造リチウムマンガン酸化物を用いた。分解抑制剤として0.6質量部または5質量部のPRSと1質量部のVCとを添加し、抵抗上昇抑制剤として0.1質量部または9質量部のTMPIを添加して非水電解液を作製したこと以外は実施例１と同様にして、実施例１２，１３のリチウムイオンニ次電池を作製した。実施例１２，１３は、主に正極活物質の平均粒径が実施例１と異なる例である。 (Preparation of Lithium Ion Secondary Battery of Examples 12 and 13)
A layered structure lithium manganese oxide having an average particle diameter of 6 μm was used as a positive electrode active material. A non-aqueous electrolyte was prepared by adding 0.6 parts by mass or 5 parts by mass of PRS and 1 part by mass of VC as a decomposition inhibitor and 0.1 parts by mass or 9 parts by mass of TMPI as a resistance increase inhibitor. Lithium ion secondary batteries of Examples 12 and 13 were produced in the same manner as Example 1 except for the above. Examples 12 and 13 are examples in which the average particle diameter of the positive electrode active material is mainly different from that in Example 1.
　（実施例１４，１５のリチウムイオン二次電池の作製）
　正極活物質として平均粒径が3μmの層状構造リチウムマンガン酸化物を用いた。分解抑制剤として2.5質量部または5質量部のPRSと1質量部のVCとを添加し、抵抗上昇抑制剤として0.2質量部または5質量部のTMPIを添加して非水電解液を作製したこと以外は実施例１と同様にして、実施例１４，１５のリチウムイオンニ次電池を作製した。実施例１４，１５も、主に正極活物質の平均粒径が実施例１と異なる例である。 (Production of Lithium Ion Secondary Battery of Examples 14 and 15)
A layered structure lithium manganese oxide having an average particle diameter of 3 μm was used as a positive electrode active material. A non-aqueous electrolyte was prepared by adding 2.5 parts by mass or 5 parts by mass of PRS and 1 part by mass of VC as a decomposition inhibitor and 0.2 parts by mass or 5 parts by mass of TMPI as a resistance increase inhibitor. Lithium ion secondary batteries of Examples 14 and 15 were produced in the same manner as Example 1 except for the above. Examples 14 and 15 are also examples in which the average particle diameter of the positive electrode active material is mainly different from that in Example 1.
　（比較例１のリチウムイオン二次電池の作製）
　正極活物質として平均粒径が8μmの層状構造リチウムマンガン酸化物を用いた。支持塩溶液100質量部に対して、分解抑制剤として1質量部のVC（ビニレンカーボネート）のみを添加して非水電解液を作製した。言い換えると、分解抑制剤としての環状スルホン酸エステル、および抵抗上昇抑制剤は添加しなかった。その他は実施例１と同様にして、比較例１のリチウムイオンニ次電池を作製した。比較例１は、正極活物質の平均粒径が実施例１と同じ条件下において、ニ次電池の初期出力の極大化を目指した例である。 (Production of Lithium Ion Secondary Battery of Comparative Example 1)
A layered structure lithium manganese oxide having an average particle size of 8 μm was used as a positive electrode active material. A non-aqueous electrolyte was prepared by adding only 1 part by mass of VC (vinylene carbonate) as a decomposition inhibitor to 100 parts by mass of the supporting salt solution. In other words, cyclic sulfonic acid esters as decomposition inhibitors and resistance increase inhibitors were not added. A lithium ion secondary battery of Comparative Example 1 was produced in the same manner as Example 1 except for the above. Comparative Example 1 is an example aiming to maximize the initial output of the secondary battery under the same conditions as in Example 1 with the average particle diameter of the positive electrode active material.
　（比較例２，３のリチウムイオン二次電池の作製）
　支持塩溶液100質量部に対して、分解抑制剤として0.5質量部または3質量部のPRS（1,3-プロペンスルトン）と1質量部のVCとを添加して非水電解液を作製した。言い換えると、抵抗上昇抑制剤は添加しなかった。その他は実施例１と同様にして、比較例２，３のリチウムイオンニ次電池を作製した。比較例２，３は、正極活物質の平均粒径が実施例１と同じ条件下において、ニ次電池の寿命の極大化を目指した例である。 (Fabrication of lithium ion secondary battery of Comparative Examples 2 and 3)
A non-aqueous electrolyte was prepared by adding 0.5 parts by mass or 3 parts by mass of PRS (1,3-propenesultone) as a decomposition inhibitor and 1 part by mass of VC to 100 parts by mass of the supporting salt solution. In other words, no resistance increase inhibitor was added. The other conditions were the same as in Example 1 to fabricate lithium ion secondary batteries of Comparative Examples 2 and 3. The comparative examples 2 and 3 are the examples which aimed at the maximization of the life of a secondary battery on the conditions same as Example 1 in the average particle diameter of a positive electrode active material.
　（比較例４，５のリチウムイオン二次電池の作製）
　支持塩溶液100質量部に対して、分解抑制剤として1質量部のVCのみを添加し（環状スルホン酸エステルを添加せず）、抵抗上昇抑制剤として3質量部または7質量部の亜リン酸トリメチル（TMPI）を添加して非水電解液を作製した。その他は実施例１と同様にして、比較例４，５のリチウムイオンニ次電池を作製した。比較例４，５は、正極活物質の平均粒径が実施例１と同じ条件下において、ニ次電池の初期容量の極大化を目指した例である。 (Fabrication of lithium ion secondary battery of Comparative Examples 4 and 5)
To 100 parts by mass of the supporting salt solution, only 1 part by mass of VC is added as a decomposition inhibitor (no cyclic sulfonic acid ester is added), and 3 parts by mass or 7 parts by mass of phosphorous acid as a resistance increase inhibitor Trimethyl (TMPI) was added to prepare a non-aqueous electrolyte. The other conditions were the same as in Example 1 to prepare lithium ion secondary batteries of Comparative Examples 4 and 5. The comparative examples 4 and 5 are the examples aiming at the maximization of the initial capacity of the secondary battery under the same conditions as the example 1 in the average particle diameter of the positive electrode active material.
　（比較例６のリチウムイオン二次電池の作製）
　支持塩溶液100質量部に対して、分解抑制剤として5質量部のPRSと1質量部のVCとを添加し、抵抗上昇抑制剤として12質量部のTMPIを添加して非水電解液を作製した。その他は実施例１と同様にして、比較例６のリチウムイオンニ次電池を作製した。比較例６は、有機リン化合物（抵抗上昇抑制剤）の添加率が本発明の規定を外れる例である。 (Fabrication of a lithium ion secondary battery of Comparative Example 6)
A non-aqueous electrolyte is prepared by adding 5 parts by mass of PRS as a decomposition inhibitor and 1 part by mass of VC to 100 parts by mass of a supporting salt solution and adding 12 parts by mass of TMPI as a resistance increase inhibitor. did. A lithium ion secondary battery of Comparative Example 6 was produced in the same manner as in Example 1 except for the above. Comparative Example 6 is an example in which the addition rate of the organic phosphorus compound (resistance increase inhibitor) deviates from the definition of the present invention.
　（比較例７，８，１５のリチウムイオン二次電池の作製）
　正極活物質として平均粒径が10μmの層状構造リチウムマンガン酸化物（比較例７）と、平均粒径が6μmの層状構造リチウムマンガン酸化物（比較例８）と、平均粒径が3μmの層状構造リチウムマンガン酸化物（比較例１５）とを用意した。その他は比較例１と同様にして、比較例７，８，１５のリチウムイオンニ次電池を作製した。比較例７，８，１５は、それぞれの正極活物質平均粒径において、比較例１と同様に、ニ次電池の初期出力の極大化を目指した例である。 (Production of lithium ion secondary battery of Comparative Examples 7, 8 and 15)
A layered structure lithium manganese oxide (Comparative Example 7) having an average particle size of 10 μm as a positive electrode active material, a layered structure lithium manganese oxide (Comparative Example 8) having an average particle size of 6 μm, and a layered structure having an average particle size of 3 μm Lithium manganese oxide (Comparative Example 15) was prepared. The other conditions were the same as in Comparative Example 1, and lithium ion secondary batteries of Comparative Examples 7, 8 and 15 were produced. Comparative Examples 7, 8 and 15 are examples aiming at maximizing the initial output of the secondary battery in each positive electrode active material average particle diameter, as in Comparative Example 1.
　（比較例９，１６のリチウムイオン二次電池の作製）
　正極活物質として平均粒径が6μmまたは3μmの層状構造リチウムマンガン酸化物を用いた。その他は比較例２と同様にして、比較例９，１６のリチウムイオンニ次電池を作製した。比較例９，１６は、それぞれの正極活物質平均粒径において、比較例２と同様に、ニ次電池の寿命の極大化を目指した例である。 (Production of lithium ion secondary battery of Comparative Examples 9 and 16)
A layered structure lithium manganese oxide having an average particle diameter of 6 μm or 3 μm was used as a positive electrode active material. The other conditions were the same as in Comparative Example 2, and lithium ion secondary batteries of Comparative Examples 9 and 16 were produced. The comparative examples 9 and 16 are the examples which aimed at the maximization of the life of a secondary battery similarly to the comparative example 2 in each positive electrode active material average particle diameter.
　（比較例１０，１７のリチウムイオン二次電池の作製）
　正極活物質として平均粒径が6μmまたは3μmの層状構造リチウムマンガン酸化物を用いた。その他は比較例３と同様にして、比較例１０，１７のリチウムイオンニ次電池を作製した。比較例１０，１７も、それぞれの正極活物質平均粒径において、比較例３と同様に、ニ次電池の寿命の極大化を目指した例である。 (Fabrication of lithium ion secondary battery of Comparative Examples 10 and 17)
A layered structure lithium manganese oxide having an average particle diameter of 6 μm or 3 μm was used as a positive electrode active material. Others were carried out similarly to the comparative example 3, and produced the lithium ion secondary battery of the comparative examples 10 and 17. Similarly to Comparative Example 3, Comparative Examples 10 and 17 also aim to maximize the life of the secondary battery in each of the positive electrode active material average particle sizes.
　（比較例１１，１８のリチウムイオン二次電池の作製）
　正極活物質として平均粒径が6μmまたは3μmの層状構造リチウムマンガン酸化物を用いた。その他は比較例４と同様にして、比較例１１，１８のリチウムイオンニ次電池を作製した。比較例１１，１８は、それぞれの正極活物質平均粒径において、比較例４と同様に、ニ次電池の初期容量の極大化を目指した例である。 (Production of Lithium Ion Secondary Battery of Comparative Examples 11 and 18)
A layered structure lithium manganese oxide having an average particle diameter of 6 μm or 3 μm was used as a positive electrode active material. The other conditions were the same as in Comparative Example 4 to fabricate lithium ion secondary batteries of Comparative Examples 11 and 18. The comparative examples 11 and 18 are the examples aiming at maximization of the initial capacity of the secondary battery in each positive electrode active material average particle diameter similarly to the comparative example 4.
　（比較例１２，１９のリチウムイオン二次電池の作製）
　正極活物質として平均粒径が6μmまたは3μmの層状構造リチウムマンガン酸化物を用いた。その他は比較例５と同様にして、比較例１２，１９のリチウムイオンニ次電池を作製した。比較例１２，１９も、それぞれの正極活物質平均粒径において、比較例５と同様に、ニ次電池の初期容量の極大化を目指した例である。 (Production of Lithium Ion Secondary Battery of Comparative Examples 12 and 19)
A layered structure lithium manganese oxide having an average particle diameter of 6 μm or 3 μm was used as a positive electrode active material. Others were carried out similarly to the comparative example 5, and produced the lithium ion secondary battery of the comparative examples 12 and 19. Similar to Comparative Example 5, Comparative Examples 12 and 19 are also examples aiming to maximize the initial capacity of the secondary battery in each positive electrode active material average particle diameter.
　（比較例１３，１４，２０，２１のリチウムイオン二次電池の作製）
　正極活物質として平均粒径が6μmまたは3μmの層状構造リチウムマンガン酸化物を用いた。支持塩溶液100質量部に対して、分解抑制剤として0.5～5質量部のPRS（1,3-プロペンスルトン）と1質量部のVC（ビニレンカーボネート）とを添加し、抵抗上昇抑制剤として0.1～10質量部のTMPI（亜リン酸トリメチル）を添加して非水電解液を作製した。その他は実施例１と同様にして、比較例１３，１４，２０，２１のリチウムイオンニ次電池を作製した。比較例１３，１４，２０，２１は、それぞれの正極活物質平均粒径において、環状スルホン酸エステル（分解抑制剤）または有機リン化合物（抵抗上昇抑制剤）の添加率が本発明の規定を外れる例である。 (Fabrication of lithium ion secondary battery of Comparative Examples 13, 14, 20, 21)
A layered structure lithium manganese oxide having an average particle diameter of 6 μm or 3 μm was used as a positive electrode active material. 0.5 to 5 parts by mass of PRS (1,3-propenesultone) as a decomposition inhibitor and 1 part by mass of VC (vinylene carbonate) are added to 100 parts by mass of a supporting salt solution, and 0.1 as a resistance increase inhibitor. A non-aqueous electrolyte was prepared by adding ̃10 parts by mass of TMPI (trimethyl phosphite). The other conditions were the same as in Example 1 to fabricate lithium ion secondary batteries of Comparative Examples 13, 14, 20, and 21. In Comparative Examples 13, 14, 20 and 21, the addition ratio of the cyclic sulfonic acid ester (degradation inhibitor) or the organophosphorus compound (resistance increase inhibitor) deviates from the definition of the present invention in each positive electrode active material average particle diameter. It is an example.
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000008
Figure JPOXMLDOC01-appb-T000008
Figure JPOXMLDOC01-appb-T000009
Figure JPOXMLDOC01-appb-T000009
　（リチウムイオン二次電池の初期化）
　上記で用意したリチウムイオン二次電池に対し、次のような手順で初期化を行った。はじめに、開回路の状態から電池電圧が4.2 Vになるまで、3時間率相当の定電流にて充電した。電池電圧が4.2 Vに達した後は、電流値が0.1時間率相当になるまで4.2 Vを保持した。以後、この２つの充電工程を「標準条件での充電」と称し、充電されたその状態を「満充電」と称す。その後、充電を停止し、30分間の休止時間を設けた（以後、この工程を単に「休止」と称する）。次いで、3時間率相当の定電流の放電を開始し、電池電圧が2.7 Vに達するまで放電させた（以後、この工程を「標準条件での放電」と称する）。その後、放電を停止し、休止を行った（30分間の休止時間を設けた）。その後、「標準条件での充電」、「休止」、「標準条件での放電」、「休止」のサイクルを3回繰り返した。次に、「標準条件での充電」、「休止」を行い、3時間率相当の定電流の放電を開始し、電池電圧が3.8 Vに達するまで放電させた。以後、この状態を「半充電」と称する。最後に、1週間のエージング期間を設け、初期化とした。 (Initialization of lithium ion secondary battery)
Initialization was performed on the lithium ion secondary battery prepared above according to the following procedure. First, the battery was charged at a constant current equivalent to a 3-hour rate until the battery voltage reached 4.2 V from the open circuit state. After the battery voltage reached 4.2 V, 4.2 V was maintained until the current value became equivalent to a 0.1 hour rate. Hereinafter, these two charging steps will be referred to as "charging under standard conditions", and the charged state will be referred to as "full charge". After that, charging was stopped and a 30-minute rest time was provided (hereinafter, this step is simply referred to as "rest"). Next, discharge at a constant current equivalent to a 3-hour rate was started, and discharged until the battery voltage reached 2.7 V (hereinafter, this process is referred to as “discharge under standard conditions”). Thereafter, the discharge was stopped and rested (a rest time of 30 minutes was provided). After that, the cycle of “charge under standard conditions”, “rest”, “discharge under standard conditions”, and “rest” was repeated three times. Next, “charging under standard conditions” and “resting” were performed, discharge of a constant current equivalent to a 3-hour rate was started, and discharging was performed until the battery voltage reached 3.8 V. Hereinafter, this state is referred to as "half charge". Finally, an aging period of 1 week was provided and initialized.
　なお、ここで言う時間率とは、電池の設計放電容量を所定の時間で放電する電流値と定義する（以下、同様）。例えば、上述の3時間率とは、電池の設計容量を3時間で放電する電流値である。さらに具体的には電池の容量をC（単位：Ah）とすると、3時間率の電流値はC/3（単位：A）となる。 In addition, with the time rate said here, it is defined as the electric current value which discharges the design discharge capacity of a battery in predetermined time (following, the same). For example, the above-mentioned 3-hour rate is a current value that discharges the designed capacity of the battery in 3 hours. More specifically, assuming that the capacity of the battery is C (unit: Ah), the 3-hour rate current value is C / 3 (unit: A).
　（試験評価）
　（a）初期容量評価
　初期化の完了したリチウムイオン二次電池を用いて、初期容量を測定した。「標準条件での充電」、「休止」、「標準条件での放電」、「休止」のサイクルを3回繰り返し、各回の放電容量の平均値を当該二次電池の初期容量とした。結果を後述する表４～６に示す。 (Test evaluation)
(A) Initial Capacity Evaluation Initial capacity was measured using a lithium ion secondary battery for which initialization was completed. The cycle of "charge under standard conditions", "rest", "discharge under standard conditions", and "rest" was repeated three times, and the average value of the discharge capacity of each cycle was taken as the initial capacity of the secondary battery. The results are shown in Tables 4 to 6 described later.
　なお、表１に示したグループ（実施例１～１１および比較例１～７、正極活物質平均粒径が8μmと10μmのグループ）では、当該グループ内で初期容量の極大化を目指した比較例４の初期容量を「1.00」として規格化して表記した（表４）。表２に示したグループ（実施例１２，１３および比較例８～１４、正極活物質平均粒径が6μmのグループ）では、当該グループ内で初期容量の極大化を目指した比較例１１の初期容量を「1.00」として規格化して表記した（表５）。表３に示したグループ（実施例１４，１５および比較例１５～２１、正極活物質平均粒径が3μmのグループ）では、当該グループ内で初期容量の極大化を目指した比較例１８の初期容量を「1.00」として規格化して表記した（表６）。 In the groups shown in Table 1 (Examples 1 to 11 and Comparative Examples 1 to 7, groups of 8 μm and 10 μm in average particle diameter of positive electrode active material), comparative examples aiming at maximizing initial capacity in the group The initial capacity of 4 was standardized and represented as "1.00" (Table 4). In the groups shown in Table 2 (Examples 12 and 13 and Comparative Examples 8 to 14, a group in which the average particle diameter of the positive electrode active material is 6 μm), the initial capacity of Comparative Example 11 aiming to maximize the initial capacity in the group Was standardized and represented as "1.00" (Table 5). In the groups shown in Table 3 (Examples 14 and 15 and Comparative Examples 15 to 21, a group in which the average particle diameter of the positive electrode active material is 3 μm), the initial capacity of Comparative Example 18 aiming to maximize the initial capacity in the group Was standardized and represented as "1.00" (Table 6).
　（b）初期抵抗測定による出力評価
　初期容量を評価したリチウムイオン二次電池を用いて、初期抵抗を測定した。「標準条件での充電」、「休止」、により電池を満充電とし、その後、1時間率相当の電流値で10秒間放電をした。満充電状態での電圧V0と10秒放電後の電池電圧V10と電流値I0とから、下記式（１）を用いて当該二次電池の初期抵抗値R0を算出した。
R0 ＝ (V0 － V10)/I0　　　　　　　　　・・・式（１）。 (B) Output evaluation by initial resistance measurement The initial resistance was measured using the lithium ion secondary battery which evaluated initial capacity. The battery was fully charged by "charge under standard conditions" and "rest", and thereafter, it was discharged for 10 seconds at a current value corresponding to an hour rate. The initial resistance value R 0 of the secondary battery was calculated from the voltage V 0 in the fully charged state, the battery voltage V 10 after discharging for 10 seconds, and the current value I 0 using the following equation (1).
R 0 = (V 0 - V 10) / I 0 ··· Equation (1).
　リチウムイオン二次電池の出力は抵抗に反比例することから、初期抵抗の逆数を初期出力の指標とした。結果を表４～６に併記する。なお、表１に示したグループでは、当該グループ内で初期出力の極大化を目指した比較例１の初期出力を「1.00」として規格化して表記した（表４）。表２に示したグループでは、当該グループ内で初期出力の極大化を目指した比較例８の初期出力を「1.00」として規格化して表記した（表５）。表３に示したグループでは、当該グループ内で初期出力の極大化を目指した比較例１５の初期容量を「1.00」として規格化して表記した（表６）。 Since the output of the lithium ion secondary battery is inversely proportional to the resistance, the reciprocal of the initial resistance is used as an index of the initial output. The results are shown in Tables 4 to 6. In the group shown in Table 1, the initial output of Comparative Example 1 aiming at maximizing the initial output in the group was normalized and represented as "1.00" (Table 4). In the group shown in Table 2, the initial output of Comparative Example 8 aiming at the maximization of the initial output in the group was normalized and represented as "1.00" (Table 5). In the group shown in Table 3, the initial capacity of Comparative Example 15 aiming to maximize the initial output in the group was standardized and represented as "1.00" (Table 6).
　（c）寿命評価
　初期容量を評価したリチウムイオン二次電池を用いて、次のような手順でサイクル試験を実施した。まず、二次電池を50℃の恒温槽内に入れ、二次電池の表面温度が50℃になった後、12時間待機した。その後、「休止」を設けずに、「標準条件での充電」、「標準条件での放電」のサイクルを2000回繰り返した。サイクル試験後の二次電池の容量（試験後容量）を測定し、寿命（サイクル試験後の容量と定義）を評価した。試験後容量の測定は、初期容量の測定手順と同一とした。結果を表４～６に併記する。 (C) Life evaluation The cycle test was implemented in the following procedures using the lithium ion secondary battery which evaluated initial capacity. First, the secondary battery was placed in a thermostat of 50 ° C., and after the surface temperature of the secondary battery reached 50 ° C., the standby was performed for 12 hours. After that, the cycle of "charging under standard conditions" and "discharging under standard conditions" was repeated 2000 times without providing "rest". The capacity (post-test capacity) of the secondary battery after the cycle test was measured, and the life (defined as the capacity after the cycle test) was evaluated. The post-test volume measurement was identical to the initial volume measurement procedure. The results are shown in Tables 4 to 6.
　なお、先と同様に、表１に示したグループでは、当該グループ内で寿命の極大化を目指した比較例３の試験後容量を「1.00」として規格化して表記した（表４）。表２に示したグループでは、当該グループ内で寿命の極大化を目指した比較例１０の試験後容量を「1.00」として規格化して表記した（表５）。表３に示したグループでは、当該グループ内で寿命の極大化を目指した比較例１７の試験後容量を「1.00」として規格化して表記した（表６）。 In the same manner as described above, in the group shown in Table 1, the post-test capacity of Comparative Example 3 aiming to maximize the life in the group was standardized and represented as "1.00" (Table 4). In the group shown in Table 2, the post-test capacity of Comparative Example 10 aiming to maximize the life within the group was standardized and represented as "1.00" (Table 5). In the group shown in Table 3, the post-test capacity of Comparative Example 17 aiming to maximize the life in the group was standardized and represented as "1.00" (Table 6).
Figure JPOXMLDOC01-appb-T000010
Figure JPOXMLDOC01-appb-T000010
Figure JPOXMLDOC01-appb-T000011
Figure JPOXMLDOC01-appb-T000011
Figure JPOXMLDOC01-appb-T000012
Figure JPOXMLDOC01-appb-T000012
　前述したように、正極活物質の粒径が小さくなると、比表面積が大きくなるため二次電池の出力は向上するが、非水電解液の分解が促進されて寿命特性が低下する傾向があり、粒径が大きくなると、比表面積が小さくなるため、非水電解液の分解が抑制されて寿命特性は向上するが、出力が十分に得られなくなる傾向がある。上記実験においても、これらの傾向が確認された。すなわち、初期出力においては「比較例７＜比較例１＜比較例８＜比較例１５」であり、試験後容量においては「比較例３＞比較例１０＞比較例１７」であった。 As described above, when the particle diameter of the positive electrode active material is reduced, the specific surface area is increased and the output of the secondary battery is improved, but the decomposition of the non-aqueous electrolyte tends to be promoted and the life characteristics tend to be deteriorated. When the particle size is increased, the specific surface area is decreased, so that the decomposition of the non-aqueous electrolyte is suppressed and the life characteristics are improved, but there is a tendency that the output can not be obtained sufficiently. These tendencies were also confirmed in the above experiment. That is, the initial output was "Comparative Example 7 <Comparative Example 1 <Comparative Example 8 <Comparative Example 15", and the post-test capacity was "Comparative Example 3> Comparative Example 10> Comparative Example 17".
　大型電気機器に適用するリチウムイオン二次電池に対しては、従来以上の高容量化・高出力化・長寿命化の強い要求があり、それら３項目において高いレベルでバランスさせることが非常に重要である。ただし、それら３項目のどれをより優先するかについては用途に依存する。そこで、上述の実験では、正極活物質の平均粒径による各グループの比較例の中で、高容量化・高出力化・長寿命化の内のいずれか１項目に特化した比較例の結果を基準として評価した。そして、これらの基準に対して、初期容量、初期出力については「０．９５以上」を合格と判定し、試験後容量については「0.90以上」を合格と判定した。 There is a strong demand for higher capacity, higher power, longer life than before for lithium ion secondary batteries applied to large-sized electrical devices, and it is very important to balance these three items at a high level It is. However, it depends on the application as to which of these three items is given higher priority. Therefore, in the above-described experiment, among the comparative examples of each group according to the average particle diameter of the positive electrode active material, the result of the comparative example specialized in any one of high capacity, high output, and long life. Was evaluated on the basis of Then, with respect to these criteria, the initial capacity and the initial output were determined to pass “0.95 or more”, and the post-test capacity was determined to pass “0.90 or more”.
　表１，４に示したように、比較例１は、非水電解液への添加剤の添加を極力抑えたことから、初期容量、初期出力は両立できているが、寿命特性が低い。正極活物質の平均粒径を10μmとした比較例７は、初期出力の極大化を目指したにもかかわらず従来技術と同等のレベルであった。そして、比較例１を基準としたときに不合格であった。本発明が目的とするリチウムイオン二次電池は、大型電気機器用の二次電池であることから、初期出力において従来よりも高出力化することが必達である。この結果から、正極活物質の平均粒径としては、10μm未満が好ましいことが確認された。 As shown in Tables 1 and 4, in Comparative Example 1, since the addition of the additive to the non-aqueous electrolyte was suppressed as much as possible, the initial capacity and the initial output are compatible, but the life characteristics are low. Comparative Example 7 in which the average particle diameter of the positive electrode active material was 10 μm was at the same level as that of the prior art despite the aim of maximizing the initial output. And when it made the comparative example 1 a reference | standard, it was a failure. Since the lithium ion secondary battery targeted by the present invention is a secondary battery for a large-sized electric device, it is essential to increase the initial output in comparison with the conventional one. From this result, it was confirmed that the average particle diameter of the positive electrode active material is preferably less than 10 μm.
　比較例２，３は、非水電解液の分解抑制に主眼を置いていることから、寿命特性は改善されるが、出力特性が不十分となってしまった。比較例４，５は、分解抑制剤の作用に起因する内部抵抗上昇の抑制に主眼を置いていることから、初期容量・初期出力は目標に到達するものの、寿命特性が未達となった。 In Comparative Examples 2 and 3, since the main object is to suppress the decomposition of the non-aqueous electrolyte, the life characteristics are improved but the output characteristics are insufficient. Since Comparative Examples 4 and 5 place emphasis on suppressing the increase in internal resistance caused by the action of the decomposition inhibitor, although the initial capacity and initial output reach the target, the life characteristics have not been reached.
　また、比較例６は、非水電解液が分解抑制剤としての環状スルホン酸エステルと抵抗上昇抑制剤としての有機リン化合物とを含有しているが、それらの添加量（含有率）が不適当なため、初期容量、初期出力および試験後容量の３項目の全てを同時に合格することができなかった（初期容量および初期出力が0.95以上、試験後容量が0.90以上にならなかった）。 In addition, in Comparative Example 6, the non-aqueous electrolytic solution contains a cyclic sulfonic acid ester as a decomposition inhibitor and an organic phosphorus compound as a resistance increase inhibitor, but the addition amount (content ratio) thereof is inappropriate. Because of this, it was not possible to pass all three items of initial capacity, initial output and post-test capacity at the same time (initial capacity and initial output was 0.95 or more, and post-test capacity was not 0.90 or more).
　これらに対し、本発明に係る実施例１～１１は、平均粒径8μmの正極活物質を用い、非水電解液が分解抑制剤としての環状スルホン酸エステルと抵抗上昇抑制剤としての有機リン化合物とをそれぞれ適切な添加量（含有率）で含有していることから、初期容量、初期出力および試験後容量の全ての項目において要求されるレベルをクリアすることが確認された。また、本発明の基本思想の範囲内では、実施例７～９に示したようにVCの添加によって試験後容量が改善されることが確認され、実施例１０，１１に示したように非水溶媒や支持塩の種類を変えた場合でも上記３項目の全てにおいて要求されるレベルをクリアすることが確認された。 On the other hand, in Examples 1 to 11 according to the present invention, a positive electrode active material having an average particle diameter of 8 μm is used, and a non-aqueous electrolyte contains a cyclic sulfonic acid ester as a decomposition inhibitor and an organic phosphorus compound as a resistance increase inhibitor. It was confirmed that the level required in all items of the initial capacity, the initial output, and the volume after test was cleared by containing each in an appropriate addition amount (content rate). Also, within the scope of the basic idea of the present invention, as shown in Examples 7 to 9, it was confirmed that addition of VC improves the post-test capacity, and as shown in Examples 10 and 11, non-water Even when the type of solvent or supporting salt was changed, it was confirmed that all of the above three items satisfied the required level.
　表２，５に示したように、正極活物質の平均粒径を6μmとしたグループにおいても、比較例８は、初期容量・初期出力が両立できているが、寿命特性が低い。比較例１０は、寿命特性が改善されたが、出力特性が不十分であった。比較例９は、寿命特性と出力特性とが不十分であった。比較例１１，１２は、初期容量・初期出力が合格であったが、寿命特性が著しく低下した。比較例１３，１４は、添加剤の添加量（含有率）が不適当なため、初期容量、初期出力および試験後容量の３項目の全てを同時に合格することができなかった。 As shown in Tables 2 and 5, even in the group in which the average particle diameter of the positive electrode active material is 6 μm, in Comparative Example 8, although the initial capacity and the initial output are compatible, the life characteristics are low. In Comparative Example 10, the life characteristics were improved, but the output characteristics were insufficient. In Comparative Example 9, the life characteristics and the output characteristics were insufficient. In Comparative Examples 11 and 12, although the initial capacity and initial output passed, the life characteristics significantly decreased. In Comparative Examples 13 and 14, since the additive amount (content ratio) of the additive was inadequate, all of the three items of the initial capacity, the initial output and the volume after the test could not be passed simultaneously.
　これらに対し、本発明に係る実施例１２，１３は、平均粒径6μmの正極活物質を用い、所定の添加剤をそれぞれ適切な添加量（含有率）で含有していることから、初期容量、初期出力および試験後容量の全ての項目において要求されるレベルをクリアすることが確認された。 On the other hand, in Examples 12 and 13 according to the present invention, since the positive electrode active material having an average particle diameter of 6 μm is used and the predetermined additive is contained at an appropriate addition amount (content ratio), the initial capacity is It was confirmed to clear the required level in all items of initial output and post test volume.
　なお、表１，４と比較して、環状スルホン酸エステルおよび有機リン化合物の含有率が異なるのは、正極活物質の平均粒径の差異に起因すると考えられる。正極活物質の粒径が小さくなると比表面積が増大するため、非水溶媒の分解を抑制するためには、より多くの分解抑制剤が必要となる。平均粒径の小さい実施例１２は、実施例１よりも多くの環状スルホン酸エステルが必要になると考えられる。また、比表面積が増大すると、有機リン化合物の分解に関与する領域が増加するため、長寿命化を果たすためには、小粒径化に伴って有機リン化合物の添加量を抑制する必要があると考えられる。 In addition, compared with Table 1, 4, it is thought that the content rate of a cyclic sulfonic acid ester and an organophosphorus compound differs from the difference of the average particle diameter of a positive electrode active material. Since the specific surface area increases as the particle size of the positive electrode active material decreases, more decomposition inhibitors are required to suppress the decomposition of the non-aqueous solvent. Example 12 with a smaller average particle size is considered to require more cyclic sulfonic acid ester than Example 1. In addition, when the specific surface area is increased, the region involved in the decomposition of the organic phosphorus compound is increased. Therefore, in order to achieve the long life, it is necessary to suppress the addition amount of the organic phosphorus compound as the particle diameter is reduced. it is conceivable that.
　表３，６に示したように、正極活物質の平均粒径を3μmとしたグループにおいても、比較例１５は、初期容量・初期出力が両立できているが、寿命特性が低い。比較例１７は、寿命特性が改善されたが、出力特性が不十分であった。比較例１６は、寿命特性と出力特性とが不十分であった。比較例１８，１９は、初期容量・初期出力が合格であったが、サイクル試験が完了する前に寿命を迎え、寿命特性が評価できなかった。比較例２０，２１は、添加剤の添加量（含有率）が不適当なため、初期容量、初期出力および試験後容量の３項目の全てを同時に合格することができなかった。 As shown in Tables 3 and 6, even in the group in which the average particle diameter of the positive electrode active material is 3 μm, in Comparative Example 15, although the initial capacity and the initial output can be compatible, the life characteristics are low. In Comparative Example 17, the life characteristics were improved, but the output characteristics were insufficient. In Comparative Example 16, the life characteristics and the output characteristics were insufficient. In Comparative Examples 18 and 19, although the initial capacity and initial output passed, the life reached the end before the cycle test was completed, and the life characteristics could not be evaluated. In Comparative Examples 20 and 21, because the additive amount (content ratio) of the additive was inadequate, all three items of the initial capacity, the initial output and the volume after the test could not be passed simultaneously.
　これらに対し、本発明に係る実施例１４，１５は、平均粒径3μmの正極活物質を用い、所定の添加剤をそれぞれ適切な添加量（含有率）で含有していることから、初期容量、初期出力および試験後容量の全ての項目において要求されるレベルをクリアすることが確認された。 On the other hand, in Examples 14 and 15 according to the present invention, since the positive electrode active material having an average particle diameter of 3 μm is used and the predetermined additive is contained in an appropriate addition amount (content ratio), the initial capacity is It was confirmed to clear the required level in all items of initial output and post test volume.
　［実験２］
　（リチウムイオン二次電池システムの作製と評価）
　本発明に係る二次電池システムとして、図２に示した構成の二次電池システムを作製した。リチウムイオン二次電池101a，101bには、前述した実施例１のリチウムイオン二次電池を使用した。発電装置222としては、風力発電機を模擬した装置を用いた。 [Experiment 2]
(Preparation and evaluation of lithium ion secondary battery system)
As a secondary battery system according to the present invention, a secondary battery system having the configuration shown in FIG. 2 was produced. The lithium ion secondary battery of Example 1 described above was used as the lithium ion secondary batteries 101a and 101b. As the power generation device 222, a device simulating a wind power generator was used.
　発電装置222における発電状況に合わせて、リチウムイオン二次電池101a，101bの充放電を行いながら、外部機器219に電力を供給する実験を行った。その結果、5時間率放電まで実施し、1時間率放電時の容量に対して90％の高い容量が得られることを確認した。また、充電においては、3時間率の充電が可能であり、所望の動作が可能であることを確認した。 An experiment was conducted to supply power to the external device 219 while performing charge and discharge of the lithium ion secondary batteries 101a and 101b according to the power generation situation in the power generation device 222. As a result, it was carried out up to 5 hour rate discharge, and it was confirmed that a high capacity of 90% was obtained with respect to the capacity at 1 hour rate discharge. Moreover, in charge, charge of a 3-hour rate was possible, and it confirmed that a desired operation | movement was possible.
　以上説明したように、本発明によれば、二次電池における容量、出力および寿命の３項目が従来よりも高いレベルでバランスしたリチウムイオン二次電池を提供できることが実証された。本発明に係るリチウムイオン二次電池およびそれを用いた二次電池システムは、特に、電池容量が大きい産業用など大型電気機器に好適に用いることができる。 As described above, according to the present invention, it has been demonstrated that a lithium ion secondary battery can be provided in which the three items of capacity, output and life in the secondary battery are balanced at a level higher than before. INDUSTRIAL APPLICABILITY The lithium ion secondary battery and the secondary battery system using the same according to the present invention can be suitably used particularly for large-sized electric devices such as industrial batteries having a large battery capacity.
　上述した実施形態や実施例は、本発明の理解を助けるために説明したものであり、本発明は、記載した具体的な構成のみに限定されるものではない。例えば、ある実施例の構成の一部を他の実施例の構成に置き換えることが可能であり、また、ある実施例の構成に他の実施例の構成を加えることも可能である。すなわち、本発明は、本明細書の実施形態や実施例の構成の一部について、削除・他の構成に置換・他の構成の追加をすることが可能である。 The embodiments and examples described above are described in order to help the understanding of the present invention, and the present invention is not limited to only the specific configurations described. For example, part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. That is, in the present invention, it is possible to delete, replace, and add other configurations to some of the configurations of the embodiments and examples of the present specification.
　１０１，１０１ａ，１０１ｂ…リチウムイオン電池、１０２…電池容器、１０３…蓋、１０４…正極外部端子、１０５…負極外部端子、１０６…注液口、１０７…正極、１０８…負極、１０９…セパレータ、１１０…正極リード線、１１１…負極リード線、１１２…絶縁性シール材料、２１３，２１４，２１５，２１７，２１８，２２０，２２１…電力ケーブル、２１６…充放電制御機構、２１９…外部機器、２２２…発電装置。 101, 101a, 101b: lithium ion battery, 102: battery container, 103: lid, 104: positive electrode external terminal, 105: negative electrode external terminal, 106: injection port, 107: positive electrode, 108: negative electrode, 109: separator, 110 ... Positive electrode lead wire, 111 ... Negative electrode lead wire, 112 ... Insulating sealing material, 213, 214, 215, 217, 218, 220, 221 ... Power cable, 216 ... Charge / discharge control mechanism, 219 ... External equipment, 222 ... Power generation apparatus.

Claims (10)

  1. 　正極、負極および非水電解液を備えたリチウムイオン二次電池であって、
    前記非水電解液は、支持塩と非水溶媒と分解抑制剤と抵抗上昇抑制剤とを含み、
    前記分解抑制剤は、環状スルホン酸エステルを含み、
    前記抵抗上昇抑制剤は、下記一般化学式（１）および/または（２）で表される有機リン化合物（ただし、化学式中のR1～R6はそれぞれ一般式CnH2n+1（nは0または正の整数）で表される基である）からなり、
    前記正極は、正極活物質として層状構造を有するリチウムマンガン酸化物を含み、該リチウムマンガン酸化物の平均粒径が3μm以上10μm未満であることを特徴とするリチウムイオン二次電池。
    Figure JPOXMLDOC01-appb-C000001
    Figure JPOXMLDOC01-appb-C000002
         A lithium ion secondary battery comprising a positive electrode, a negative electrode and a non-aqueous electrolyte, comprising:
    The non-aqueous electrolyte contains a support salt, a non-aqueous solvent, a decomposition inhibitor, and a resistance increase inhibitor.
    The decomposition inhibitor includes cyclic sulfonic acid ester,
    The resistance increase inhibitor is an organophosphorus compound represented by the following general chemical formula (1) and / or (2) (with the proviso that R 1 to R 6 in the chemical formula are each represented by general formula C n H 2 n + 1 (n is 0 or a positive integer))
    The said positive electrode contains the lithium manganese oxide which has layered structure as a positive electrode active material, The average particle diameter of this lithium manganese oxide is 3 micrometers or more and less than 10 micrometers, The lithium ion secondary battery characterized by the above-mentioned.
    Figure JPOXMLDOC01-appb-C000001
    Figure JPOXMLDOC01-appb-C000002
  2. 　請求項１に記載のリチウムイオン二次電池において、
    前記リチウムマンガン酸化物の平均粒径が3μm以上5μm未満の範囲にあり、
    前記環状スルホン酸エステルは、プロパンスルトンおよび/または1,3-プロペンスルトンであり、該環状スルホン酸エステルの含有率が前記支持塩と前記非水溶媒との合計100質量部に対して2.5質量部以上5質量部以下であり、
    前記有機リン化合物は、亜リン酸トリメチル、亜リン酸トリエチル、ジメチルメチルホスホナートおよびジエチルメチルホスホナートの内の少なくとも１種であり、該有機リン化合物の含有率が前記支持塩と前記非水溶媒との合計100質量部に対して0.2質量部以上5質量部以下であることを特徴とするリチウムイオン二次電池。     In the lithium ion secondary battery according to claim 1,
    The average particle size of the lithium manganese oxide is in the range of 3 μm to less than 5 μm,
    The cyclic sulfonic acid ester is propane sultone and / or 1,3-propene sultone, and the content of the cyclic sulfonic acid ester is 2.5 parts by mass with respect to a total of 100 parts by mass of the supporting salt and the non-aqueous solvent 5 parts by mass or less,
    The organic phosphorus compound is at least one of trimethyl phosphite, triethyl phosphite, dimethyl methyl phosphonate and diethyl methyl phosphonate, and the content of the organic phosphorus compound is the support salt and the non-aqueous solvent And 0.2 to 5 parts by mass with respect to a total of 100 parts by mass of the lithium ion secondary battery.
  3. 　請求項１に記載のリチウムイオン二次電池において、
    前記リチウムマンガン酸化物の平均粒径が5μm以上7μm未満の範囲にあり、
    前記環状スルホン酸エステルは、プロパンスルトンおよび/または1,3-プロペンスルトンであり、該環状スルホン酸エステルの含有率が前記支持塩と前記非水溶媒との合計100質量部に対して0.6質量部以上5質量部以下であり、
    前記有機リン化合物は、亜リン酸トリメチル、亜リン酸トリエチル、ジメチルメチルホスホナートおよびジエチルメチルホスホナートの内の少なくとも１種であり、該有機リン化合物の含有率が前記支持塩と前記非水溶媒との合計100質量部に対して0.1質量部以上9質量部以下であることを特徴とするリチウムイオン二次電池。     In the lithium ion secondary battery according to claim 1,
    The average particle size of the lithium manganese oxide is in the range of 5 μm to less than 7 μm,
    The cyclic sulfonic acid ester is propane sultone and / or 1,3-propene sultone, and the content of the cyclic sulfonic acid ester is 0.6 parts by mass with respect to 100 parts by mass in total of the supporting salt and the non-aqueous solvent. 5 parts by mass or less,
    The organic phosphorus compound is at least one of trimethyl phosphite, triethyl phosphite, dimethyl methyl phosphonate and diethyl methyl phosphonate, and the content of the organic phosphorus compound is the support salt and the non-aqueous solvent And 0.1 to 9 parts by mass with respect to a total of 100 parts by mass of the lithium ion secondary battery.
  4. 　請求項１に記載のリチウムイオン二次電池において、
    前記リチウムマンガン酸化物の平均粒径が7μm以上10μm未満の範囲であり、
    前記環状スルホン酸エステルは、プロパンスルトンおよび/または1,3-プロペンスルトンであり、該環状スルホン酸エステルの含有率が前記支持塩と前記非水溶媒との合計100質量部に対して0.1質量部以上5質量部以下であり、
    前記有機リン化合物は、亜リン酸トリメチル、亜リン酸トリエチル、ジメチルメチルホスホナートおよびジエチルメチルホスホナートの内の少なくとも１種であり、該有機リン化合物の含有率が前記支持塩と前記非水溶媒との合計100質量部に対して0.1質量部以上11質量部以下であることを特徴とするリチウムイオン二次電池。     In the lithium ion secondary battery according to claim 1,
    The average particle size of the lithium manganese oxide is in the range of 7 μm to less than 10 μm,
    The cyclic sulfonic acid ester is propane sultone and / or 1,3-propene sultone, and the content of the cyclic sulfonic acid ester is 0.1 parts by mass with respect to a total of 100 parts by mass of the support salt and the nonaqueous solvent. 5 parts by mass or less,
    The organic phosphorus compound is at least one of trimethyl phosphite, triethyl phosphite, dimethyl methyl phosphonate and diethyl methyl phosphonate, and the content of the organic phosphorus compound is the support salt and the non-aqueous solvent And 0.1 to 11 parts by mass with respect to a total of 100 parts by mass of the lithium ion secondary battery.
  5. 　請求項１乃至請求項４のいずれかに記載のリチウムイオン二次電池において、
    前記分解抑制剤は、ビニレンカーボネートを更に含むことを特徴とするリチウムイオン二次電池。     The lithium ion secondary battery according to any one of claims 1 to 4.
    The said decomposition inhibitor further contains vinylene carbonate, The lithium ion secondary battery characterized by the above-mentioned.
  6. 　請求項１乃至請求項５のいずれかに記載のリチウムイオン二次電池において、
    前記リチウムマンガン酸化物は、LidMneNifCogQhO2（ただし、d＋e＋f＋g＋h＝2、1.0≦d≦1.2、0.1≦e≦0.5、0.2≦f≦0.6、0.1≦g≦0.5、0≦h≦0.1、QはB、Mg、Al、Cu、Zn、MoおよびWからなる群より選ばれる少なくとも１種である）で表わされる化合物であることを特徴とするリチウムイオン二次電池。     The lithium ion secondary battery according to any one of claims 1 to 5.
    The lithium manganese oxide, Li d Mn e Ni f Co g Q h O 2 ( however, d + e + f + g + h = 2,1.0 ≦ d ≦ 1.2,0.1 ≦ e ≦ 0.5,0.2 ≦ f ≦ 0.6,0.1 ≦ g ≦ 0.5, It is a compound represented by 0 <= h <= 0.1 and Q is at least 1 sort (s) chosen from the group which consists of B, Mg, Al, Cu, Zn, Mo, and W). The lithium ion secondary battery characterized by the above-mentioned.
  7. 　請求項１乃至請求項６のいずれかに記載のリチウムイオン二次電池において、
    前記非水溶媒は、その主成分として、エチレンカーボネート、エチルメチルカーボネートおよびジメチルカーボネートの内の少なくとも１種を含むことを特徴とするリチウムイオンニ次電池。     The lithium ion secondary battery according to any one of claims 1 to 6.
    The lithium ion secondary battery, wherein the non-aqueous solvent contains, as its main component, at least one of ethylene carbonate, ethyl methyl carbonate and dimethyl carbonate.
  8. 　請求項１乃至請求項７のいずれかに記載のリチウムイオン二次電池において、
    前記支持塩は、六フッ化リン酸リチウムおよび/または四フッ化ホウ酸リチウムを含むことを特徴とするリチウムイオンニ次電池。     In the lithium ion secondary battery according to any one of claims 1 to 7,
    The lithium ion secondary battery, wherein the supporting salt comprises lithium hexafluorophosphate and / or lithium tetrafluoroborate.
  9. 　請求項１乃至請求項８のいずれかに記載のリチウムイオンニ次電池において、
    前記負極は、負極活物質として非晶質炭素を含むことを特徴とするリチウムイオンニ次電池。     The lithium ion secondary battery according to any one of claims 1 to 8.
    The said negative electrode contains amorphous carbon as a negative electrode active material, The lithium ion secondary battery characterized by the above-mentioned.
  10. 　請求項１乃至請求項９のいずれかに記載のリチウムイオンニ次電池を用いたことを特徴とする二次電池システム。 A secondary battery system using the lithium ion secondary battery according to any one of claims 1 to 9.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110574211A (en) * 2017-04-26 2019-12-13 远景Aesc能源元器件有限公司 Lithium ion secondary battery, method for manufacturing lithium ion secondary battery, and electrolyte for lithium ion secondary battery

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010044883A (en) * 2008-08-08 2010-02-25 Mitsui Chemicals Inc Nonaqueous electrolyte and lithium secondary battery
WO2010150508A1 (en) * 2009-06-22 2010-12-29 日立ビークルエナジー株式会社 Lithium-ion secondary battery
CN102610859A (en) * 2012-04-04 2012-07-25 山东鸿正电池材料科技有限公司 Non-aqueous electrolyte for lithium manganate power battery
JP2012256435A (en) * 2011-06-07 2012-12-27 Sumitomo Metal Mining Co Ltd Nickel manganese composite hydroxide particle and production method thereof, positive electrode active material for nonaqueous electrolyte secondary battery and production method thereof, and nonaqueous electrolyte secondary battery

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010044883A (en) * 2008-08-08 2010-02-25 Mitsui Chemicals Inc Nonaqueous electrolyte and lithium secondary battery
WO2010150508A1 (en) * 2009-06-22 2010-12-29 日立ビークルエナジー株式会社 Lithium-ion secondary battery
JP2012256435A (en) * 2011-06-07 2012-12-27 Sumitomo Metal Mining Co Ltd Nickel manganese composite hydroxide particle and production method thereof, positive electrode active material for nonaqueous electrolyte secondary battery and production method thereof, and nonaqueous electrolyte secondary battery
CN102610859A (en) * 2012-04-04 2012-07-25 山东鸿正电池材料科技有限公司 Non-aqueous electrolyte for lithium manganate power battery

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110574211A (en) * 2017-04-26 2019-12-13 远景Aesc能源元器件有限公司 Lithium ion secondary battery, method for manufacturing lithium ion secondary battery, and electrolyte for lithium ion secondary battery

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