ENERGY STORAGE SYSTEM

An energy storage system according to an aspect of the present disclosure includes a control container having a battery system controller (BSC), a master controller connected to the BSC through a first communication line, and a bank battery management system (BBMS) connected to the BSC through a second communication line; and a battery container including a slave controller connected to the master controller through the first communication line, and a rack battery management system (RBMS) connected to the BBMS through the second communication line and for monitoring a state of a corresponding battery rack.