If you haven’t seen/heard about it yet. LiPo batteries can be dangerous, check it out. It is very rare that a lipo would ignite under normal use. It would take charging it at a higher rate than recommended (typically 1C) or a internal short. People have had serious property damage, here is a list of what causes the fire and what is damaged. They make commercial battery bunkers, some people use cinder blocks and bags of sand. I have also seen ammo cans used, but I could not find them locally and I didn’t want to pay for shipping. I found a honeywell steel lockbox at WalMart for $10, that is pretty stout. I don’t have the desire to test it (yet), but I think is should hold just fine. Also to help suppress any fire that could arise, I put a Pyrex pan over the battery. I did buy one of those LiPo charging bags, but it is a pain to open and close every time I want to charge a battery. I have it lining the bottom of the box. it is definitely not necessary, but since I have it, why not. The way I see it, all this effort is the cheapest fire insurance available.