A filler head for a storage system includes a body to be mounted inclined according to a predetermined angle regarding the gravity direction, called the filling direction, and including a main part closed by a cover part so as to form a cavity in which a separating device is received, the filler head being configured to receive, in a cylindrical wall of the separating device extending around the filling direction, a distribution nozzle of a fluid with an automatic stop sensor to prevent overfilling of the filler head, the separating device being arranged to improve the partitioning of a flow coming from a venting line and the flow going to the filling line. The separating device further includes a flange, protruding transversally from the outside surface of the cylindrical wall and mounted in the cavity upstream of the sensor of the nozzle when received in the cylindrical wall.