BATTERY SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a battery system capable of determining the amount of active lithium which cannot be dissolved in lithium ions due to breakage of active lithium although active lithium can be normally dissolved in lithium ions.SOLUTION: A controller (40) calculates the total amount (Q) of active lithium when a precipitation reaction and a dissolution reaction are performed on the basis of reaction current when the precipitation reaction and the dissolution reaction are performed. The ratio (γ) between the total amount of active lithium and the amount of active lithium which is generated and does not conduct the dissolution reaction due to breakage of active lithium can be calculated on the basis of at least one of a current value under charging of a lithium ion secondary battery and a duration time under charging. The ratio increases as the current value under charging is larger, and the ratio increases as the duration time is longer. The amount (Q) of active lithium which does not conduct the dissolution reaction can be calculated by calculating the total amount (Q) of active lithium and the ratio (γ).