The invention relates to a blower filter system with a blower unit (11), which has an electric motor (24) for driving a blower impeller, a control unit (27) for controlling the electric motor, contacts (22, 23) for connecting to a battery pack, and a battery pack (10), which has a plurality of secondary cells (12) with high energy density and contacts (22, 23) for connecting to the blower unit. The blower unit (11) can be detachably coupled to the battery pack (10), the battery pack thereby being electrically connected to the blower unit via the contacts. The battery pack (10) is provided with protective circuits, said protective circuits comprising electronic components (15, 16, 17, 18, 19, 20, 21, 31) which are designed to electrically switch off at least one of the plurality of secondary cells (12) of the battery pack if excessive currents and/or excessive temperatures occur. Moreover, the battery pack (10) and the blower unit (11) are each at least partially cast in a casting compound.