NONAQUEOUS-ELECTROLYTE SECONDARY BATTERY

摘要

This invention provides a nonaqueous-electrolyte secondary battery that, while exhibiting excellent cycle characteristics due to the use of a carbonaceous material that exhibits little expansion and contraction during charging and discharging, exhibits both the low internal resistance and the charging-curve shape with a large sloped region that are in demand for HEV applications and the like, resulting in excellent input characteristics. Said nonaqueous-electrolyte secondary battery is provided with the following: a positive electrode containing a positive-electrode active material that comprises a lithium-containing transition-metal composite oxide; a negative electrode containing a negative-electrode active material that contains a carbonaceous material; and a nonaqueous electrolyte. This nonaqueous-electrolyte secondary battery has a positive-electrode capacity (the capacity with metallic lithium used as the other electrode) of at most 3.0 mAh/cm2; the true density of the carbonaceous material, as determined using a butanol method, is between 1.45 and 1.70 g/cm3, inclusive; and the ratio (A/B) of the positive-electrode capacity (A) to the negative-electrode capacity (B) is between 0.4 and 0.8, inclusive.