Nonaqueous electrolyte secondary battery

摘要

Disclosed is a nonaqueous electrolyte secondary battery, comprising a case (1) having a wall thickness (X) not larger than 0.3 mm, a positive electrode (6) provided in the case (1), a negative electrode (9) provided in the case (1) and the negative electrode containing a carbonaceous material capable of absorbing-desorbing lithium ions, and a nonaqueous electrolyte provided in the case (1) and the nonaqueous electrolyte containing a nonaqueous solvent including gamma -butyrolactone and a solute dissolved in the nonaqueous solvent, wherein after being discharged to 3V with a current of 0.2C at room temperature, the voltage reduction caused by the self-discharge at 60 DEG C is not larger than 1.5V in 3 weeks.