The invention relates to an unmanned aerial vehicle with an energy accumulator (20), which is connected releasably to a structural component (29) of the aerial vehicle, and with an accumulator plug (32), via which electrical energy is conducted from the energy accumulator (20) to a rotor drive (18) of the aerial vehicle. In an operating position, a locking element (25) locks the energy accumulator (20) in relation to the structural component (29) and, in a maintenance position, releases the energy accumulator (20), wherein a full engagement of the accumulator plug (32) is blocked at the same time. The invention also relates to an energy accumulator for such an aerial vehicle, and to a method for attaching an energy accumulator to such an aerial vehicle. It can easily be checked by means of the invention whether the energy accumulator has been attached correctly.