| 摘要 |
PURPOSE: A lithium ion secondary battery is provided to ensure excellent charge/discharge properties and also excellent storage properties without segregation of lithium compounds on a graphite cathode. CONSTITUTION: A lithium ion secondary battery comprises an aprotic electrolyte containing a sulfonate ester having at least two sulfonyl groups and graphite as principal component of negative electrode active substance layers, the density of the negative electrode active substance layers being not less than 0.90 g/cm^3 and not more than 1.65 g/cm^3. The electrolyte volume is not less than 1.25 times and not more than 1.65 times of the void volume that the positive electrode, the negative electrode and the separator possess. |
