There are four things that one should never do with lithium batteries, or they will explode in a fireball that could potentially kill people or animals. A really bad idea if they go off in your smartphone that's in your pocket... this is why if I feel my smartphone getting hot while charging, I immediately disconnect it and let it cool down. I then try a slower charger.
Don't:
Warning: don't try this at home, kids.
Don't:
- Get them wet
- Burn them in a fire, or just let them get hot
- Puncture them
- Short circuit them
Warning: don't try this at home, kids.