So what do the safety circuits do?
Like, I get the chemistry behind the lithium ion batteries. Lithium cobalt oxide, or lithium iron phosphate, and then intercalating between the graphite layers and move back and forth to charge. And lithium is pretty light and reactive, so that causes the thing to hold a powerful charge. But what purpose and role does the electronics play in this? What do they do? Other than the complex chemistry involved, what prevented lithium ion batteries from propagating earlier?