I know these batteries have had problems with exploding and fires. I know very little about electricity.

I have recently noticed a very small drill (great for model making) that has a 4 volt Lith-Ion battery but its charger shows an output of 6 volts.

My question: Wouldn't this kinda overload the smaller capacity and cause overheating and possible explosions????

My Makita 18V drill uses a large charger with a fan in it. It shows an output as "7.2V/7,2V-18V - 9A". Don't understand what all that stuff means, but it seems to work great while it constantly monitors itself. It's the little devil I worry about.