Fan filter device comprising - a fan unit for generating an air flow, - a filter receptacle for accommodating a filter unit , - an internal energy storage unit , - an energy interface , - a current-limiting apparatus which is selectively able to be activated or deactivated, - a sensor arrangement and - a control device , wherein the internal energy storage unit - is electrically connected both to the fan unit and to the energy interface and - is rechargeable with electrical energy and is able to deliver electrical energy and wherein the energy interface is selectively - able to be electrically connected to a power supply unit or - able to be electrically disconnected from the latter, wherein the fan filter device is configured such that the current-limiting apparatus is activated at least when the energy interface is disconnected from the power supply unit , wherein the activated current-limiting apparatus is configured to keep the intensity of a current from the energy interface to the internal energy storage unit below a predefined limit current intensity, wherein the sensor arrangement is configured to detect a predefined deactivating event, and wherein the control device is configured so as, after the deactivating event has been detected, to deactivate the current-limiting apparatus in such a way that, after the deactivation, the internal energy storage unit is electrically connected to the energy interface without being limited to the limit current intensity, characterized in that the deactivating event has occurred - when the state of charge (U) of the internal energy storage unit has exceeded a predefined state-of-charge limit (UO) and/or - when a predefined period of time (ΔT) has elapsed since an electrical connection was established between the energy interface and the power supply unit . - a fan unit for generating an air flow, - a filter receptacle for accommodating a filter unit , - an internal energy storage unit , - an energy interface , - a current-limiting apparatus which is selectively able to be activated or deactivated, - a sensor arrangement and - a control device , - is electrically connected both to the fan unit and to the energy interface and - is rechargeable with electrical energy and is able to deliver electrical energy and - able to be electrically connected to a power supply unit or - able to be electrically disconnected from the latter, wherein the activated current-limiting apparatus is configured to keep the intensity of a current from the energy interface to the internal energy storage unit below a predefined limit current intensity, wherein the sensor arrangement is configured to detect a predefined deactivating event, and wherein the control device is configured so as, after the deactivating event has been detected, to deactivate the current-limiting apparatus in such a way that, after the deactivation, the internal energy storage unit is electrically connected to the energy interface without being limited to the limit current intensity, characterized in that the deactivating event has occurred - when the state of charge (U) of the internal energy storage unit has exceeded a predefined state-of-charge limit (UO) and/or - when a predefined period of time (ΔT) has elapsed since an electrical connection was established between the energy interface and the power supply unit . - when the state of charge (U) of the internal energy storage unit has exceeded a predefined state-of-charge limit (UO) and/or - when a predefined period of time (ΔT) has elapsed since an electrical connection was established between the energy interface and the power supply unit . <EOS>