Extremely Lightweight Hydrogen Fuel Cells

The fuel cell power supplies of today are two times too heavy compared to man-portable power supplies. A major portion of the weight is in the fuel cell stack, a stack of carbon electrodes with metal bipolar plate separators that are sandwiched between two end plates and held in place by tie rods. We continue to investigate lighter weight materials to use in our conventional fuel cell stack. However, in this effort we propose to investigate an innovative design, the strip cell stack, that completely eliminates the bipolar plates, end plates and tie rods. The strip stack is 4.6 times lighter than a bipolar fuel cell stack. In a conventional Proton Exchange Membrane (PEM) fuel cell stack, electrons and protons are conducted perpendicular to the electrode plane. In the strip cell design, ionic conduction is perpendicular to the plane of the electrodes while electron flow is in the plane of the electrodes. Phase I will demonstrate the feasibility of the design with a 4 cell "substack." In Phase II we will build a coiled 300 watt cell "stack." The coiled strip cell stack is formed from a sheet of planar strip cells rolled together and placed inside a thin lightweight plastic tube. The 300 watt strip cell stack should fit in a tube which is about 8.9 cm. in diameter and 20.3 cm. long. The total weight should be slightly over 1 Kg.