Intrinsically safe backup power supply for combustible environments

摘要

An intrinsically safe supply for supplying back-up power during a power-out event incorporates one or more rechargeable fuel cells. The power supply is provided with switching circuitry operable to provide an output back-up current from the fuel cells upon a power-out event. The fuel cells are housed within a sealed metal housing immersed within an electricity insulating potting material chosen to arrest spark formation and/or electrically insulate any created sparks. The fuel cells comprise sealed lithium iron based fuel cells for supplying back-up electrical current. A charging circuit electrically connects the fuel cells with an external power source for providing a charging current during normal power-on conditions.