Lyman:
The standard set by the FAA for this safety critical event is one occurrence in one Billion flight hours.
FALSE.
That standard does not apply to the battery system, as it is not critical for flight.
I urge contributors to this thread to please refrain from posting unfounded hyperbole. It does nothing to further our understanding of the technical issues at hand, bothers those professionals well versed in the industry standards, and misleads the gullible.