| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a lithium ion secondary battery having excellent safety, and having practically sufficient charge-discharge cycle characteristic and high-rate discharge characteristic. <P>SOLUTION: The nonaqueous solvent of a nonaqueous electrolyte solution of this lithium ion secondary battery 1 contains propylene carbonate, ethylene carbonate and diethyl carbonate. The percentage content X [vol.%] of propylene carbonate, the percentage content Y [vol.%] of ethylene carbonate and the percentage content Z [vol.%] of diethyl carbonate in the nonaqueous solvent satisfy a condition expressed by the following expressions (1)-(4) at the same time. In the nonaqueous electrolyte solution, 2-15 mass% of a compound expressed by general formula (I) is included. In the formula (I), R<SP>1</SP>and R<SP>2</SP>are each independently at least one kind selected from a group comprising a hydrogen atom and 1-3C hydrocarbon groups. However, R<SP>1</SP>and R<SP>2</SP>are not hydrogen atoms at the same time. Expression (1) is 10≤X≤50; expression (2) is 1≤Y≤20; expression (3) is 30≤Z≤85; and expression (4) is X+Y+Z=100. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
