Who wouldn’t want both? Researchers in Germany and America are making great inroads on lithium battery energy density, while adding some hope that batteries may someday outlast the vehicle in which they are installed. Ulm, Germany, where the Berblinger Competition encourages economical flight, may be a resource for making such flight possible. The Zentrum für Sonnenenergie- und WasserstoffForschung Baden-Württemberg (Centre for Solar Energy and Hydrogen Research Baden-Württemberg, ZSW), has announced what they claim to be world-beating cells in terms of cycle life. Dr. Margret Wohlfahrt-Mehrens, Head of the Accumulator Material Research Department in Ulm reports, “After 10,000 complete charging and discharging cycles with a complete charge and discharge cycle per hour (2 C), our lithium batteries still have more than 85 % of the initial capacity.” This would be equivalent to a full charge and discharge cycle every day for over 27 years. With active materials exclusively from Germany, the Ulm battery competes with those manufactured in Asia for power …
Oxis Energy and Lithium Sulfur Batteries
Taking one last look at 2011’s fifth annual Electric Aircraft Symposium, your editor regrets the fits and starts in its coverage. Next week, we’ll begin looking at the extraordinary presentations from this year’s gathering. Huw W. Hampton-Jones from Oxis Energy, a British company developing a Lithium Sulfur battery, claimed his firm’s “technology is based around the use of Lithium Sulphur to produce batteries which are superior in terms of energy, weight, cycle life, costs, ageing and safety.” Lithium sulfur is well known in military circles for providing primary (non-rechargeable) power to field operations. Perlan I flew with SAFT 5590 primary batteries, partly because of their superior energy density compared to lithium-ion cells, and partly because of their greater resistance to thermal runaways, or self-igniting fires sometimes seen in lithium batteries. Weight was a significant concern on this high-altitude craft. When working on the fringes of the battery selection effort for Perlan II, headed by Einar Enevoldson, James Murray and Eric …
QinetiQ Zephyr Breaks Official Record for Solar-Powered Endurance
According to BBC News and GlobalFlight.com, QinetiQ’s Zephyr, a 22.5 meter (72 feet) unmanned, solar-powered aircraft has been in the air for more than a week over the Yuma, Arizona Proving Grounds, and program managers intend to keep it there for a total time of at least fourteen days. Having flown since 6:40 a.m. July 9, its endurance is now four times that of any other unmanned aerial vehicle. A US Global Hawk holds the current official world endurance record for an unmanned aerial vehicle (UAV) of 30 hours, 24 minutes. Zephyr’s record is being certified by the Federation Aeronautique Internationale, the world air sports federation. Jon Saltmarsh, Zephyr’s project manager, says the craft, “Is basically the first ‘eternal aircraft,’” a name once given to AeroVironment’s Helios and related aircraft. The 50 kilogram (110 pound) unmanned airplane emulates the flight pattern followed by Andre’ Borschberg in taking the Solar Impulse to a world record for manned solar-powered airplanes. Its thin solar cells power the twin …
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