On batteries and aeroplanes

Earlier this week I wrote about space-crafts with thermostatic skins, implying this kind of technology could prove to be useful for temperature control in low-power autonomous seismic stations in the Antarctic. Here is another technological achievement that may be of some use.

The BBC reported over the weekend that a UK-built solar-powered and unmanned plane, the Zephyr-6, had stayed aloft for more than three days, running though the night on batteries it had recharged during the day.

The Zephyr weighs 30kg and flies at an altitude of over 60,000 feet. Its power derives from solar power generated by paper-thin amorphous silicon solar arrays glued over the aircraft's wings. This power is stored in a new type of lithium-sulphur battery.

A lot of effort has gone into power storage and light-weighting the systems. Lithium sulphur is more than double the energy density of the best alternative technology which is lithium polymer batteries. Mr Kelleher, Qinetiq (UK defense and research firm)

These batteries are made by the Sion Corporation:

The custom built Li-S battery pack was designed and assembled by SION Power and consisted of 576 cells built into a battery configuration of 12 cells in series and 48 in parallel. The battery utilized SION’s unique, high specific energy Li-S cells (350 Wh/kg). At ~10 kg, the Li-S battery pack was carefully engineered to minimize total pack weight.
In addition to providing flight power, the battery pack supplied power to a special
internal pack heating system to maintain the batteries at 0oC throughout the cold nights. Sion press release.

The Sion battery data-sheet is available here: sion_product_spec.pdf.

The usefulness of this kind of battery for our stations in Antarctica would depend on its adaptability to long-duration low-power applications, and on its performance at low temperatures. Yet another thing to look into this fall!