Frightening! These batteries were just cargo. Makes you wonder about using Lithium Ion batteries for anything other than low current applications, aboard an aircraft. They just don't seem to stack well together. Once you space them, so enough air circulates around them to cool them, any space saving advantage is gone over conventional batteries. Maybe they need to be liquid cooled, like a car engine or World War One machine gun, to be close enough together to save space. Of course, it may be better to just go to conventional batteries, but, it's my understanding, that Boeing has painted itself into a corner, on the 787, and can't go to another battery type, because of some needed characteristic of the Lithium Ion battery. Something about rate of current draw, maybe. I don't recall.