DEVICE AND METHOD FOR PREVENTING OVER-DISCHARGE OF ENERGY STORAGE DEVICE AND RE-OPERATING SAME

Provided is an energy storage system including: an external power input unit receiving uninterrupted external power; a battery storing electric power; a power adjustment device adjusting the uninterrupted external power and the power of the battery, the battery including a battery module with one or more battery cells; a battery management system; a main switch disposed on a power path between the battery module and the battery management system and a path between the battery module and the power adjustment device; and a wake-up relay receiving a wake-up signal from the power adjustment device and transmitting the wake-up signal to the battery management system.