TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Parameter: A porosity of the negative electrode excluding the current collector is 20-50%. The Li insertion potential of the negative electrode active material is 0.2-3 V (vs. Li/Li+). The average primary particle diameter of the negative electrode active material is 0.001-1 microns. The specific surface area of the negative electrode is 5-50 m2/g.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Component: The negative electrode active material includes a lithium titanium oxide and/or a titanium-containing composite oxide. The lithium titanium oxide is of formula Li4+xTi5O12 (1) or Li2+xTi3O7. The active material of the positive electrode includes Li-nickel-cobalt-manganese (Li-Ni-Co-Mn) composite oxide, a Spinel-type Li-Mn-Ni composite oxide, a Li-phosphorus (LiP) oxide having an olivine structure, a Li-Co oxide, a Li-Ni-Co composite oxide, or a Li-Mn composite oxide. The Li-Ni-Co-Mn composite oxide is of formula LiaNibCocMndO2. The nonaqueous electrolyte contains an ionic liquid. The nonaqueous electrolyte contains a molten salt containing Li ion, organic cation having a skeletal structure of formula (A) and anion. The anion includes BF4-, PF6-, AsF6-, ClO4-, CF3SO3-, CF3COO-, CH3COO-, CO32-, N(CF3SO2)2-, N(C2F5SO2)2-, or (CF3SO2)3C-x=-1 to 3;a=0-1.1;b,d=0.1-0.5;c=0-0.9.    TECHNOLOGY FOCUS - METALLURGY - Preferred Component: The titanium-containing composite oxide contains P, vanadium, tin, copper, Ni or iron. The current collector is formed of aluminum (Al) or Al alloy.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Component: The negative electrode active material includes a lithium titanium oxide and/or a titanium-containing composite oxide. The lithium titanium oxide is of formula Li4+xTi5O12 (1) or Li2+xTi3O7. The active material of the positive electrode includes Li-nickel-cobalt-manganese (Li-Ni-Co-Mn) composite oxide, a Spinel-type Li-Mn-Ni composite oxide, a Li-phosphorus (LiP) oxide having an olivine structure, a Li-Co oxide, a Li-Ni-Co composite oxide, or a Li-Mn composite oxide. The Li-Ni-Co-Mn composite oxide is of formula LiaNibCocMndO2. The nonaqueous electrolyte contains an ionic liquid. The nonaqueous electrolyte contains a molten salt containing Li ion, organic cation having a skeletal structure of formula (A) and anion. The anion includes BF4-, PF6-, AsF6-, ClO4-, CF3SO3-, CF3COO-, CH3COO-, CO32-, N(CF3SO2)2-, N(C2F5SO2)2-, or (CF3SO2)3C-x=-1 to 3;a=0-1.1;b,d=0.1-0.5;c=0-0.9.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Component: The organic cation includes alkyl imidazolium ion and/or tetraalkyl ammonium ion. The nonaqueous electrolyte contains nonaqueous solvent consisting of propylene carbonate, ethylene carbonate, diethyl carbonate or gamma-butyrolactone. EXAMPLE - A separator formed of a porous polyethylene film was put in direct contact with the positive electrode in a manner to cover the positive electrode, and the negative electrode was positioned to face the positive electrode with the separator interposed in-between to obtain a laminate structure. The laminate structure thus obtained was spirally wound to prepare an electrode group. Further, the electrode group was pressed in a manner to have a flattened shape, followed by housing the flattened electrode group in a case formed of an aluminum-containing laminate film having a thickness of 0.1 mm. On the other hand, a liquid nonaqueous electrolyte (nonaqueous electrolysis solution) was prepared by dissolving lithium tetrafluoro borate (LiBF4) used as an electrolyte in a mixed solvent consisting of ethylene carbonate (EC) and gamma-butyrolactone (BL), which were mixed at a volume ratio of 25:75. The electrolyte was dissolved in the mixed solvent at 1.5 mol/L. The nonaqueous electrolyte thus prepared was poured into the electrode group housed in the case of the laminate film to manufacture a thin nonaqueous electrolyte battery.