Speaking in Japan, home to two of the largest buyers of the Boeing 787, they said more than 500 engineers and outside experts invested more than 200,000 hours of engineering and tests to understand what may have caused lithium-ion batteries to overheat in two planes in January, The New York Times reported.
Those incidents prompted U.S. and Japanese regulators, along with officials in other countries, to ground the 50 Dreamliners already delivered.
Dreamliner's chief engineer, Michael Sinnett, said Boeing hasn't determined -- and might never know -- the exact cause of the overheating
"We looked at everything that could impact the battery," Sinnett said, "and we applied a broad set of solutions that encompasses everything that this large team of experts believed someday could happen. And it led to a very robust solution,"
Sinnett said the fix, which includes a new enclosure made of stainless steel, was designed to keep the battery from flaring by quickly depriving any flames of oxygen.