Lithium batteries come in little plastic bags. When the battery gets over-charged, the bag inflates with gas and can easily rupture. Open air can cause the lithium to ignite, and it burns like a flare. I recently replaced the battery in my GPS unit for my bicycle. Its became inflated, probably because I left it on charge for too long. I bought a new battery on Amazon and put it in, and the GPS works fine, but there's a nagging little question in the back of my mind -- what if this new battery ruptures and catches fire? It could burn my house down. I've watched videos of these batteries igniting and burning. They do go off like fire bombs. On the other hand, there are videos of people puncturing the inflated battery bags to let the gas out, and they don't ignite. Exactly what sets them off, I don't know, but I do know they are very dangerous, that their design is a design flaw, and each of them is a fire bomb waiting to go off. This includes the lithium batteries in electric cars and trucks. I think it is reason enough to ban the sale of these batteries outright, until a safer design can be brought to market.