Have LION batteries been used on any military a/c?
Or is the 787 the 1st application in any a/c?
A news source recently quoted a Boeing employee saying there was at least one (LiIon, not nesc same type) on the International Space Station, that the F35 and F22 have them and that there is at least one on the A380. They also quoted 1.3 million actual flight hours for the battery type in question, so its not all new, but has been proven in service already.
From that, I would suggest that this is either a manufacturing fault in the batteries or a problem with the circuitry/management of the battery.
I very much look forward to finding out what the probelm is, as I think most of us do!