APPARATUS AND METHOD FOR DIAGNOSING STATE OF BATTERY

An apparatus for diagnosing a state of a battery according to an embodiment of the present disclosure includes: a charging and discharging unit configured to charge or discharge a battery module; a measuring unit configured to measure a current of the battery module at every predetermined period during a cycle in which the battery module is charged or discharged; and a control unit configured to receive a measurement value for the current of the battery module from the measuring unit, estimate a SOC (State Of Charge) of the battery module during the cycle based on the received measurement value, calculate a change rate of the estimated SOC, and determine whether a defect occurs in the battery module based on a comparison result between the calculated change rate of the SOC and a preset reference change rate.