NONAQUEOUS ELECTROLYTE SECONDARY BATTERY

摘要

Disclosed is a nonaqueous electrolyte secondary battery comprising a positive electrode which contains a lithium complex oxide as the active material. In this nonaqueous electrolyte secondary battery, the charging final voltage is set at 4.25-4.5 V. In the region wherein the positive electrode and the negative electrode are arranged opposite to each other, the ratio R between the weight Wp of the active material contained in the positive electrode per unit area and the weight Wn of the active material contained in the negative electrode per unit area, namely R = Wp/Wn is within the range from 1.3 to 19. This nonaqueous electrolyte secondary battery is excellent in safety, cycle characteristics and storage characteristics even when the charging final voltage during the normal operation is set at 4.25 V or higher.