Abstract: This invention pertains to a novel pressure relief device for a container which is under pressure or becomes pressurized. In one aspect, the invention is directed to a pressure relief vent for a battery which, due to adverse chemical reaction, may become pressurized to a hazardous level. A pressure release vent for a container comprising: (a) a container having a wall; (b) an indentation formed in said wall, the indentation being interrupted by a flat-topped fold which extends across the indentation and reduces the depth of the indentation at a specific location; and (c) a score formed in said fold, the score providing a point of weakness whereby excessive pressure buildup in the container ruptures the container wall at the score location, thereby permitting pressurized gases to escape from the container.