Solar-powered unmanned airplane with lithium-sulfur battery

The Korea Aerospace Research Institute has conducted a high-altitude test flight of solar-powered unmanned aerial vehicle EAV-3, which features a lithium-sulfur battery from Korean manufacturer LG Chem.

The battery company said, in a press release, the small aircraft was conceived for long flights at a stratospheric altitude of 12km or more. The airplane engine is powered by solar cells on the 20m-long wings and 9m body. “During the daytime, it flies utilizing a solar cell and battery power as a source of energy and, during the night time, it utilizes battery power charged during the day time,” said LG Chem.

The flight test was conducted in Korean airspace from 08:36 a.m. to 09:47 p.m. at an altitude of around 22km. “It flew for seven hours, out of a total of 13 flight hours, with a stable output in the stratospheric altitude of 12-22km, where a general aircraft cannot fly,” said LG Chem.

The company said EAV-3's energy storage system had to endure difficult atmospheric conditions including temperatures of near -70 degrees Celsius and low pressure of a 25th of one atmosphere, for an environment the company described as almost a vacuum. “LG Chem plans to demonstrate a long-endurance flight that lasts more than a number of days by producing additional trial products of lithium-sulfur batteries in the future,” said the battery supplier. “Moreover, it plans to mass produce a lithium-sulfur battery that has an energy density more than twice that of the present lithium-ion battery, after 2025.”

British battery manufacturer Oxis Energy is also planning a lithium-sulfur battery powered two-seater plane. The all-electric aircraft is intended to have a flight time of more than two hours and a range of around 200 nautical miles.