All eyes in the aerospace market, especially those of safety specialists, have been on Boeing and the avionics employed by its Dreamliner 787 since a Japan Airlines (JAL) commercial airplane caught fire in Boston last month.
The National Transportation Safety Board (NTSB), roughly one month after an investigation was launched, revealed that the battery was indeed responsible for the fire. NTSB Chairman Deborah A.P. Hersman was careful, however, not to say that lithium-ion (Li-ion) batteries are intrinsically dangerous.
“I would not want to categorically say that these batteries are not safe,” Hersman is quoted as saying during a February 6 press conference. “Any new technology, any new design… there are going to be some inherent risks. The important thing is to mitigate them.”
“The 787 batteries have very large cells, the battery cells are very big and they’re quite close together and there’s not enough insulation between the cells,” Musk says. “So, if one cell goes into thermal runaway and catches on fire, it’s going to cascade into the other cells.
“The approach we take at Tesla and SpaceX is we have smaller battery cells with gaps between them,” Musk continues, “and we make sure that if there’s a thermal runaway event which creates quite a bit of fire and smoke that it directs that fire away from other cells, so you don’t have this domino effect.
“The long term solution for having a battery pack that’s reliable and safe and lasts a long time is to reduce the size of the cells,” says Musk, “and have more cells that are smaller and have bigger gaps and better thermal insulation between the cells.”