Bad news for the sun-powered Solar Impulse aircraft, which recently flew from Japan to Hawaii without using a drop of fossil fuels–technically difficulties will keep it in the ground until next spring at the earliest. Turns out the batteries overheated during the flight and were severely damaged, according to a July 15 news release sent out by the Solar Impulse team:
During the first ascend on day one of the flight from Nagoya to Hawaii, the battery temperature increased due to a high climb rate and an over insulation of the gondolas. And while the Mission Team was monitoring this very closely during the flight, there was no way to decrease the temperature for the remaining duration as each daily cycle requires an ascend to 28’000 feet and descend for optimal energy management.
Overall the airplane performed very well during the flight. The damage to the batteries is not a technical failure or a weakness in the technology but rather an evaluation error in terms of the profile of the mission and the cooling design specifications of the batteries. The temperature of the batteries in a quicks ascend / descend in tropical climates was not properly anticipated.
Irreversible damage to certain parts of the batteries will require repairs which will take several months. In parallel, the Solar Impulse engineering team will be studying various options for better cooling and heating processes for very long flights.
For now, the aircraft will stay at Kalaeloa Airport on Oahu until it can attempt to fly to the Mainland next year. The Solar Impulse is on a round-the-world trip meant to demonstrate the feasibility of solar power. Its record-making flight from Japan to Hawaii took 117 hours and 52 minutes.
For more information, go to SolarImpulse.com.
Photo: Revillard/Solar Impulse