The objective is the development of a miniature hydrogen generator for small Proton Exchange Membrane (PEM) fuel cells. Energy density of this rechargeable power source is 6 to 8 times higher than that of rechargeable batteries. The hydrogen generator is the key for utilizing the long life PEM fuel cell in External Ventricular Assist Device (EVAD) and other man- portable applications with comparatively small power but significant long- term capacity requirements. The generator development is based on the reaction of alkali or alkali-earth metal hydrides with water. Oxides or hydroxides are formed. The generator operates in a passive mode. Hydride is contained in a replaceable fuel cartridge placed in a generator receptacle. Wicking material distributed throughout the cartridge provides a water transport path to the hydride surface. Water is separated from the hydride by a microporous hydrophilic membrane. It allows water to pass, but once wet is impervious to hydrogen gas owing to its bubble pressure. Hydrogen generation is controlled by the build up of pressure which prevents additional water from entering the fuel cartridge. The proposed effort provides for (1) verification of the control concept, (2) fabrication and (3) evaluation of a breadboard system with an available 20W PEM fuel cell and design of a preprototype generator.
