| 摘要 |
PROBLEM TO BE SOLVED: To provide a battery pack including a plurality of nonaqueous electrolyte secondary batteries connected in series, in which voltage monitoring means such as a circuit for monitoring a voltage of each of the batteries can be decreased by half while deterioration in the battery pack due to variations in unit cells is suppressed and safety is maintained.SOLUTION: In the nonaqueous electrolyte battery pack, a charging voltage of a nonaqueous electrolyte secondary battery pack is set preliminarily, and a nonaqueous electrolyte secondary battery having a capacity change rate of 90% or more is adopted. The capacity change rate is a rate between a 0.1 C discharge capacity at 25°C when each of nonaqueous electrolyte batteries constituting the battery pack is charged at 25°C with a 0.1 C rate at a charging voltage higher by 0.8 V than half of the set charging voltage of the nonaqueous electrolyte secondary battery pack and a 0.1 C discharge capacity at 25°C when charged at a voltage half of the set charging voltage. |
