Direct Methanol Fuel Cell Systems for Future Force Warriors: From Experimental and Simulations for Water and Methanol Crossover and Recycling to High Performance Fuel Cell Systems

To produce a high power and high energy density direct methanol fuel cell DMFC system, it must use neat methanol as a fuel, and water produced at the cathode must be recycled. Based on Faradic reactions for DMFC, a series of theoretical equations over the entire discharge current ranges were explored and developed to model and simulate water and methanol crossover in a DMFC stack. The performance of the DMFC stack was then used to verify theoretical equations. The water and methanol crossover behavior of the DMFC system at different discharge currents was extensively investigated. The actual performance of the DMFC fuel cell stack agreed with the theoretical equations under a variety of experimental conditions. In addition to this modeling and lab-based work, a series of 20 watt DMFC systems are being developed under the Defense Acquisition Challenge Program DACP through the U. S. Army Program Executive Office PEO Soldier Project Manager Soldier Warrior PM SWAR team. The 20 watt DMFC systems were used in laboratory testing and in field exercises. The field exercises were supported by the Army Research Laboratory ARL, Natick Soldier Research, Development and Engineer Center NSRDEC, PEO Soldier and the U.S. Air Force Research Laboratory. The exercises explore the potential for using a small lightweight, high power and energy dense DMFC system for specific Soldier applications, such as for battery charging and hybrid power.