Abstract: A safety enclosure assembly for electric storage batteries of the type used in the operation of motor vehicles, marine vessels and the like is disclosed. The assembly includes a casing or container of familiar size and shape having the usual number of cells for receiving the battery plate assemblies and electrolyte. A gas diverter is provided for each cell and is in the form of a blow-out section or flap formed in the side wall of the casing. The flaps are formed by scoring the casing wall to the shape of the flaps whereby the flaps will be forced open in the event of an explosion within the case. A channel piece is fixed to the casing to form a passageway for directing any high pressure explosion gases and electrolyte downwardly towards the base of the casing. The enclosure assembly also includes cell filler units each of which has a cup-shaped well having flame arrester openings through its bottom and gas vent openings through its side wall.