APPARATUS AND METHOD FOR DETECTING ABNORMAL BATTERY CELL

An abnormal cell detection device includes a storage device storing cell voltage values detected for each rest period after discharge including a plurality of battery racks, and a control device configured to determine a maximum cell voltage value and a first minimum cell voltage value in each battery rack for each rest period, determine a first difference between the maximum cell voltage value and the first minimum cell voltage value in each battery rack for each rest period, select a target battery rack by statistically analyzing a change in the first difference value during a predetermined period, determine a second difference value between an average cell voltage and a second minimum cell voltage value in each battery module of the target battery rack for each rest period and determine a battery module including an abnormal cell in the target battery rack based on the second difference value.