Integrated Regenerative Fuel Cell Investigation.

A regenerative stack consisting of four hydrogen-oxygen fuel cells and two electrolysis cells was designed, fabricated, and successfully tested for 48 cycles. The regenerative stack was operated over the following range of parameters fuel cell current densities from 50 ampssq ft to 300 ampssq ft, and temperatures current densities from 5 ampssq ft to 90 ampssq ft, and temperatures from 70F to 200F. Proper moisture transfer between fuel cells and electrolysis cells with vapor pressure gradients as the driving force was demonstrated at all operating conditions. The integrated stack fabricated and tested under this contract consists of a planar stack of four hydrogenoxygen, alkaline electrolyte KOH, low temperature, matrix fuel cells each about 2 inches by 10 inches and a planar stack of two 4.5 inch X 10 inch electrolysis cells of similar type. Water storage matrices are located adjacent to the hydrogen electrodes of both stacks and are separated by a hydrogen plenum. Author