The battery box was to meet the new RTCA standard for LiIon batteries
Could be. I think it's a great solution to the problem.... Here's the scenario:
1) Plane flies high in the sky.... Airframe gets very cold....
2) Airframe made of composites has much lower thermal conductivity than aluminium. Nett result... airframe takes longer to get cold on the way up.... once cold... takes longer to warm up on the way down...
3) Plane lands, doors open, passengers get off. Cabin fills with air far more humid that the 15% talked about on this thread.
4) The moist air, inside the aircraft, getting close to the airframe, forms condensation.... Since the airframe is cooler than we see in aluminium airframes.... we see more condensation....
5) Water and electrical circuits don't go too well together...
6) Issues that previously were unlikely to occur, become more likely, in the more moist environment.
So by putting the battery in a sealed box.... nicely ensures that the condensation doesn't get to the battery... It wasn't poorly made batteries, or overcharging.... it was a short caused by the battery being covered in condensation.... Oh and meant to say.... the technology behind the battery wasn't the problem and this is why it didn't make sense to change to conventional batteries...
I could be wrong of course, just a theory.