Solar Impulse – Tougher than it Looked

Dean Sigler Electric Powerplants, Sustainable Aviation 1 Comment

The record-breaking flight from Nagoya, Japan to Kalaeloa, Hawaii by Andre’ Borschberg in Solar Impulse had more difficulties than were immediately apparent to even the most involved observer.  During the first climb out of Nagoya, some of the cells mounted behind each motor experienced overheating, now attributed to over-insulation.  High-density foam packed around the cells was apparently too effective for even the freezing temperatures at altitude and caused the batteries to become warmer than desired. As explained on the Solar Impulse web site, “The energy collected by the solar cells is stored in lithium polymer batteries, whose energy density is optimized to 260 [Watt-hours per kilogram]. The batteries are insulated by high-density foam and mounted in the four engine nacelles, …