ESS INCLUDING SUPERABSORBENT SHEET

An ESS (Energy Storage System) is disclosed, which includes a sub ESS stack including a plurality of sub ESSs, each having a plurality of battery modules and a battery rack for accommodating the plurality of battery modules; an ESS housing configured to accommodate the plurality of sub ESSs; a sensor installed in the ESS housing to sense at least one of temperature and smoke inside the ESS housing; a first blocking sheet interposed between the sub ESSs adjacent to each other; a fire extinguishing device configured to supply a fire extinguishing agent into the ESS housing; and a cooling device configured to supply a cooling water to the first blocking sheet.