Thin Film Power Cells for High Altitude Airships

There is a requirement for lightweight propulsion and energy storage technologies with high energy density, long service life, good reliability, thermal and radiation resistant and low cost for use in high altitude airships for defense and non-defense oriented missions. In Phase I, Lithium Power Technologies proposed and demonstrated the feasibility of the thin film, flat-pack lithium ion batteries incorporating high capacity active materials and thin film current collectors delivering specific energies of 180 Wh/kg at projected cycle life greater than existing lithium ion batteries. Our objective in Phase II will be to optimize the chemistry, components and packaging that result in a durable battery for high altitudes with specific energies greater than 215 Wh/kg and cycle life exceeding 500 cycles at 80-90% depth-of-discharge. The battery will be built with capacities of 3 Ah to 25 Ah, a storage life of 6-12 months at 0 oC, operating life of 2-3 years, and deliver peak power at C/2 to C rates. Key performance areas include, the development of very thin film plastic or thin foil current collectors, incorporating a polymer-coated separator, incorporating the highest capacity active materials, designing the battery in a large footprint and improvements in the overall packaging.