“A lithium-ion battery fire is extremely toxic and dangerous, often presenting a greater health hazard than the flames or heat themselves.Toxic Gases ReleasedWhen a battery enters thermal runaway (an uncontrolled, self-heating state where cells fail sequentially), it vents a dense cloud of poisonous and corrosive chemicals”
It should be illegal for more than a pound of lithium to be in one place.
This is why it's illegal to put lithium batteries into checked luggage on an airliner.
Lithium SMALL batteris seem to be a wonderful thing if they are correctly employed, but crazy dangerous in sufficient quantity. Much of the modern “equipment” we have uses these batteries & generally speaking, they accomplish so much.