The Boeing 787 fleet was grounded because of battery problems. The FAA has recently approved engineering fixes to their battery system, and the planes will be back in the air perhaps within weeks.
Boeing’s fixes include better insulation for the batteries’ eight cells, and a stainless steel box designed to encase the batteries and contain fire and vent possible smoke or hazardous gases out of the planes. Mike Sinnett, Boeing’s chief engineer for the 787, said that the tests performed in the last month showed the batteries were now much less likely to overheat.
Boeing, which has Federal Aviation Administration (FAA) approval to test its new battery for certification, said Friday it will encase the redesigned power pack in a steel box, pack it with added insulation, heat-resistant material and spacers, drill drain holes to remove moisture, and vent any gases from overheating directly to the atmosphere outside the aircraft.
Note that neither of these accounts describe changes to the battery cells themselves, just the packaging of the cells within the power pack.