Energy Harvesting Programs for Military Use

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The development of longer life, lighter and thinner batteries is some of the challenges facing battery manufacturers in programs such as the Land Warrior system. The battery should be paratrooper qualified, weigh below two pounds and up to 1.6 inches (4 cm) thick. The battery should power all the systems electronics, for 8-10 hours missions, including computers, communications devices and vision enhancement devices. Some innovative ideas are currently being tested for Land Warrior type applications, such as integrating rechargeable cells into the clothing of the soldier or into ammunition belts. This requires flat cells such as those used in Lithium-ion polymer rechargeable batteries. For the near term, The Army considers advanced, rechargeable and primary batteries. For the longer term, the Army is studying a one-pound rechargeable battery belt, 1.5 pound fuel cells, and 1.5 pound methanol canisters.

Further into the future, micro fuel cell solutions are considered. The fuel cell is an energy-generating device that creates power through the chemical reaction of a fuel in the presence of a catalyst. Recent results have shown that liquid hydrocarbon fuels can be converted directly into electricity in a solid oxide fuel cell. Considerable challenges are still to be tackled, primarily thermal integration, signature reduction, etc. The introduction of new materials is one of the solutions for the challenges. Porous super-thermal conductors and advanced aerogel materials are being considered for heat transfer and isolation in advanced fuel cells. Battery Intelligence’ is developing fuzzy logic methodology to monitor the state of health of power cells. Such systems could be based on impedance and other output parameters. With a carefully characterized fuel cell, it is possible to detect changes in humidity in fuel supply gas and correct it before permanent damage occurs to the fuel cell. As before, the software is code efficient and the additional logic circuitry is minimal