| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a lithium-ion secondary battery with excellent reliability which has an excellent charge/discharge property in an operation temperature from -20 to +25°C, and that, can maintain the same property for a long period. <P>SOLUTION: The lithium-ion secondary battery has a solvent of nonaqueous electrolyte solution composed of propylene carbonate, ethylene carbonate and diethyl carbonate. A propylene carbonate content X, an ethylene carbonate content Y and a diethyl carbonate content Z satisfy at the same time formula (1): 10≤X≤40, formula (2): 1≤Y≤20, formula (3): 30≤Z≤85, and formula (4): X+Y+Z=100. The nonaqueous electrolyte solution contains 3 to 6% by mass of a compound as expressed in formula (I), in which R1 and R2 may be the same or not and denote either a hydrogen atom or a hydrocarbon group with the carbon number of one to six. <P>COPYRIGHT: (C)2007,JPO&INPIT |
