| abstract |
A nonaqueous electrolyte secondary battery comprising a positive electrode (4) housed in a case (1) a negative electrode (6) arranged in the case (1) so that a separator (5) is sandwiched between the positive and negative electrodes (4, 6) consisting of lithium or lithium-containing material, and a nonaqueous electrolyte contained in the case (1) and prepared by dissolving an electrolytic salt consisting of lithium phosphate hexafluoride (LiPF₆) or lithium borofluoride (LiBF₄) in a solvent mixture consisting of ethylene carbonate, 2-methyltetrahydrofuran, and at least one ester-based nonaqueous solvent selected from the group consisting of butylene carbonate, dimethyl carbonate, γ-butyrolactone, and sulfolane. |