An ESS according to an embodiment of the present invention comprises: a sub-ESS lamination including a plurality of sub-ESSs including a plurality of battery modules and a battery rack for receiving the plurality of battery modules; an ESS housing for receiving the plurality of sub-ESSs; a sensor installed in the ESS housing to sense at least one of temperature and smoke in the ESS housing; first blocking sheets each interposed between the sub-ESSs adjacent to each other; a fire extinguishing device for supplying a fire extinguishing agent into the ESS housing; and a cooling device for supplying cooling water to the first blocking sheets.