Looks like the same problem as the Boeing 787 Dreamliner
After getting footage for the Kickstarter video for me new game, my Black Magic Camera's battery exploded, spewing smoke violently.
We ran out of there for safety reasons. However, knowing we had to get some footage of it, we put damp rags over our mouths and ran back in to grab some footage.
I've contact Black Magic Design regarding issues with Batteries, but have yet to hear back from them.