NOVELTY - The device (200) has an adhesive (216) i.e. removable adhesive such as pressure sensitive adhesive, arranged around an opening (208) in an outer surface of a battery pack (204). A hat portion (212) is arranged over the opening, and comprises an outer ring portion attached to the outer surface of the battery pack via the adhesive. An inner portion is recessed from the outer surface of the pack to form a gap between the opening and the inner portion, where diameter of the inner portion is greater than diameter of the opening and diameter of the gap is greater than diameter of the opening.    USE - Pressure relief device for being attached to an outer surface of a battery pack (claimed) in transportation applications and exemplary stationary applications such as backup power for telecommunications systems, uninterruptible power supplies (UPS) and distributed power generation applications. Uses include but are not limited to attach to outer surface of nickel metal hydride (NiMH) batteries, lead-acid batteries, lithium batteries and lithium-ion batteries in hybrid electric vehicles (HEV), plug-in HEVs, electric vehicles (EV), heavy duty vehicles (HDV) and vehicles with 42-volt electrical systems.    ADVANTAGE - The device releases high pressure gases from the battery pack in a controlled and directed manner in event of a failure of sealed enclosures. The battery charger includes a plug that interfaces with a power source so as to provide charging power to the battery pack via the battery charger. The device controls burst pressure of the pressure relief device without changing size of the opening by varying certain parameters of the pressure relief device and an exposed inner portion of the pressure relief device. The device is detached from the battery pack, thus allowing gases to vent outward through the opening.    DESCRIPTION OF DRAWING(S) - The drawing shows an exploded perspective view of a pressure relief device.    Pressure relief device (200)    Battery pack (204)    Opening (208)    Hat portion (212)    Adhesive (216)