Patent ID: 6852451

Claim:
A nonaqueous electrolyte secondary battery, comprising: a case having a wall thickness not larger than 0.3 mm; a positive electrode provided in said case; a negative electrode provided in said case and comprising a carbonaceous material capable of absorbing-desorbing lithium ions; and a nonaqueous electrolyte provided in said case and comprising a nonaqueous solvent including γ-butyrolactone and a solute dissolved in said nonaqueous solvent, wherein formulas (1) and (2) given below are satisfied: 0.92× C 60 ≦C 20 ≦0.98× C 60 (1) and 0.95× C 85 ≦C 60 ≦0.98× C 85 (2), where C 20 represents a negative electrode capacity obtained when said negative electrode of said secondary battery at the time of starting its use is charged to 0.01V versus Li with a current of 0.2 C at 20° C., followed by discharging the negative electrode to 1.5V versus Li with a current of 0.2 C at 20° C., C 60 represents a negative electrode capacity obtained when said negative electrode of said secondary battery at the time of starting its use is charged to 0.01V versus Li with a current of 0.2 C at 60° C., followed by discharging the negative electrode to 1.5V versus Li with a current of 0.2 C at 60° C., and C 85 represents a negative electrode capacity obtained when said negative electrode of said secondary battery at the time of starting its use is charged to 0.01 V versus Li with a current of 0.2 C at 85° C., followed by discharging the negative electrode to 1.5 V versus Li with a current of 0.2 C at 85° C.