Abstract: A seal material having improved sealing characteristics and useful in high temperature, corrosive environments, particularly fuel cells is disclosed. The material comprises an acid resistant, high temperature stable fluorinated elastomer and a blowing agent which activate at a temperature within the range of curing temperatures of the elastomer. Improved sealing characteristics due to volume expansion of the seal material applied and activated within the fuel cell were observed. The process of activating the seal material at the operating temperature of the fuel cell is also disclosed.The invention also discloses the process of using the seal material within a fuel cell.

Abstract: A cooler for removing waste heat from a stack of fuel cells uses a non-dielectric coolant which is carried in a plurality of tubes passing through one or more separator plates in the stack. Preferably the coolant is water so that heat removal is by evaporation of the water within the tubes by boiling. The tubes are electrically insulated from the cells by a coating of dielectric material such as polytetrafluoroethylene. In one embodiment of the present invention the cooler tubes are connected to the stack coolant supply conduits by dielectric hoses having a high length to diameter ratio to provide a several hundred thousand ohm impedance path in case of a flaw in the protective dielectric coating, in order that a short circuit of the stack does not occur.