Sometimes accidents happen.
That moment when instead of making a hole in the plastic, you make a hole in the battery.
Result: an explosion and everybody going nuts. This is the reason why we will use Life batteries and not Lipo batteries (like this one) in the final version.
What was left… R.I.P battery remains.
Everything is fine though. We took the adequate precautions and now we are making a little cemetery for our broken electronic equipment. 🙂