Pretty small, but I'm not sure if it matters. If any battery starts out-gassing when you're in an elevator, you're probably as good as dead, because the hydroge

Pretty small, but I'm not sure if it matters. If any battery starts out-gassing when you're in an elevator, you're probably as good as dead, because the hydrogen fluoride release will quickly cause tremendous damage to you or just flat out kill you; I doubt there's much you can do about it. So I definitely think that the moral of the story is simply never, ever take a large battery onto an elevator Maybe solid state batteries can some day give us more peace of mind.