a maintenance free battery having explosion resistant characteristics for multi - celled battery containers . a battery cover has a main body with an elongate recess therein extending across its length . within the first recess there are a plurality of vent well openings extending into the cells of the battery , and a plurality of vent plugs filling each opening which provide for the escape of gas and retard the escape of electrolyte . a recess plate fits snugly within the recess , the plate attaching to each of the vent plugs . provisions are made to insure that the ends of the plate seal off the ends of the recess to prevent the leakage of gas between the plate ends and recess end walls .