UPDATE: On July 15, 2015 the Solar Impulse team announced that the overheated batteries could not be repaired or replaced before the end of the season. The plane will stay in Hawaii until April 2016, when it will continue the flight around the world. Fresh off a record setting flight across the Pacific, the Solar Impulse team is still optimistic about the future.
Exploration and adventure, it’s not only when you raise the flag of success, it’s also when you have delays, problems, doubts, and that you have to build up a lot of perseverance and courage inside the team.
It’s been a week of extreme highs and lows for the Solar Impulse 2 team, which just completed the most challenging leg of a 22,000-mile journey around the world in a solar powered plane. First, a celebration: pilot André Borschberg landed safely in Hawaii after staying awake for five days and five nights to cross the Pacific Ocean in the longest solo flight in history. Unfortunately, the plane is now grounded for at least the next few weeks because of major damage to the batteries caused by overheating.
The plane’s 17,000 solar cells power four electric motors and store energy in lithium batteries which make night flying possible. During the first part of the flight from Japan to Hawaii, the battery temperature increased too much due to over insulation. Unfortunately, there was no way to decrease the temperature for the remaining duration of the flight because the plane needed to ascend and descend to and from an altitude of 28,000 feet for optimal energy management.
The damage to parts of the batteries is irreversible and will require repairs and replacements that will take several weeks. The worldwide journey started in Abu Dhabi in March, and the plane has already experienced delays with bad weather forcing an expected stop in Japan. Now, the battery repair could cause the Solar Impulse 2 to miss the weather window for crossing the Atlantic before the height of hurricane season in mid-August. The plane could be grounded in New York until next spring.
The engineering team is now investigating the issue and looking for ways to improve the heating and cooling process for long flights in the future. A member of the Solar Impulse team told us, “Solar Impulse is an experimental plane, which was constructed during 13 years. During this time span the engineer team developed a plane which can fly day and night, but there is always something new to learn. Therefore it is difficult to anticipate all possible situations. The problem with the batteries is a new situation, which is been investigated right now. The whole engineer team is working right now to find a solution for this problem so that we can continue to fly around the world without a drop of fuel.”
