This is why we always caution the people coming on here wanting to throw LiPo and Li-Ion batteries in their project. If you don't know what you're doing (and sometimes, even if you do!), the failure mode can be spectacular.
Talking of hobby robots dpa posted on SRS about the disastrous fire, which consumed nBot, caused by a short in the LiPo battery. So he rebuilt it (5 months I think) and now uses NiMh.