Not that I'm recommending it, but you could fill a coffee can with gasoline and light it on fire and with only minimum care, be completely safe.
Do the same with an equivalent-energy amount of lithium batteries and you better have a good pair of running shoes.
Go watch some youtube videos of exploding laptops.
The latest big MacBook battery has 100 watt hours of energy fully charged.
A gallon of gasoline has 33,000 watt hours of energy.
So that macbook's battery has 2.3 teaspoons, about 1 centimeter cubed, or 11 mL equivalent energy of gasoline. I have spilled that much gas on my shoe and not given it a second thought. Another way to put it is a laptop battery has about as much energy in it as a shot of vodka.
I'll happily store many bottles of liquor in the cupboard without a thought of the fire risk.
An equivalent battery carelessly stored is scary.