Metal foils in clean, renewable energy applications

Abstract

Metal strip and sheet thinner than 125 microns (0.005 inch) is, by definition, foil. Foils significantly thinner than this value have found application in two different alternative energy applications. Foils in the 15 to 5 micron range (0.0006 to 0.0002 inch) are finding use in fuel cell balance of plant applications. One hurdle to the implementation of fuel cell technology is the lack of widespread hydrogen supply infrastructure. Reforming of hydrocarbon fuels such as natural gas, propane or diesel fuel on site is one way to enable the use of fuel cells in many applications. Reforming of hydrocarbon fuels results in a reformate gas stream containing species other than hydrogen, such as nitrogen and carbon monoxide. Pure hydrogen gas can be extracted from the reformate gas stream using a permselective metal foil membrane. Hydrogen flux increases and cost decreases with membrane thickness. In another renewable energy application, stainless steel foils 25 to 50 microns (0.001 to 0.002 inches) thick are being used as substrates for advanced thin film photovoltaic cells. The use of foil substrates instead of glass makes the solar cells lighter, more rugged and processable in a continuous fashion, lowering manufacturing costs. ©2010 Society for Experimental Mechanics Inc.