A parachute inlet control system is configured to provide an improved inflation profile for solo andor clustered parachutes. Preferably the top portion of the box includes a flap with an opening, and the flap extends over a corresponding opening in the front side such that the openings align, and the slide lies between the front side of the box and the top flap. At least one vent opening is provided on a side of the frame arrangement which faces away from the end faces of the cell body, in order to allow fluid, in particular gas, to emerge from the battery cell arrangement in the event of damage.