The choice of Li-ion battery saved only 30 kg over a same performance and specifications NiMH battery used without a single insident in 6.6 million hybrids produced over the last decade. There was no valid reason to use Li-ion system in this case. Even only 1 fire in 10 million flight hours mens a fire every year once 1500 Dreamliners ar flying as Boeing hopes. Switch the battery now, it is totally unnecessary risk
