A reduction of humidity in production facilities is the key to long-lasting and powerful lithium-ion batteries. Dry room systems from Weiss Technik dehumidify the room air in battery cell production to a residual water content of up to 0.001 grams per kilogram of air. This corresponds to a dew point of -70 degrees Celsius. To keep the production climate constant under all conditions, the battery cell production chambers are hermetically sealed off from the outside climate. Dry room systems from Weiss Technik first cool down the ambient air in the production area, whereby a large part of the moisture condenses. In a second stage, specially coated drying wheels remove the residual moisture until the desired value is reached. To keep the climate in the drying chamber system constant under all conditions, the system generates a slight overpressure. This protects the chamber from the penetration of more humid outside air.