DEVICE AND METHOD FOR DETECTING POOR BATTERY CELL

An ESS capable of detecting a defective battery cell, the ESS in accordance with an exemplary embodiment, may include a plurality of battery cells, and a control unit for controlling the charge/discharge of the ESS, wherein the control unit includes an SOC calculation unit for calculating the SOC of the ESS, a voltage measurement unit for measuring the voltage of each of the plurality of battery cells, and a poor battery cell detection unit for detecting a defective battery cell from the voltages measured in the voltage measurement unit.