Why not steam-electric hybrid autos?

good idea BUT in order to make steam you need a presser vessel that would have to have very high psi if you were ever in a accident you might survive the impact but when the presser vessel blew you would not only have live steam you would have sharp metal pieces flying all over the place. and where on a car are you going to put a vessel that would be capable of making enough steam to go anywhere the thing would be to heavy defeating the purpose think electric no gas no oil no emissions no worries