APPARATUS AND METHOD FOR DETERMINING DEGRADATION STATE OF BATTERY, BATTERY PACK AND ELECTRIC VEHICLE

An apparatus for determining a degradation state of a battery includes a sensing unit configured to output sensing information indicating a voltage and a current of the battery and a control unit. The control unit determines a degradation ratio of the battery and a measured Q-dV/dQ curve based on the sensing information. The measured Q-dV/dQ curve shows a relationship between a remaining capacity of the battery and a ratio of a change in voltage of the battery to a change in remaining capacity of the battery. The control unit detects a plurality of feature points from the measured Q-dV/dQ curve. The control unit determines a positive electrode degradation ratio, a negative electrode degradation ratio and a lithium ion loss ratio of the battery based on the degradation ratio, the plurality of feature points, a predetermined positive electrode Q-dV/dQ curve and a predetermined negative electrode Q-dV/dQ curve.