Twice the energy density just means it will make a hotter, bigger fire when, not if, it ignites.
“When not if it ignites?” Are you seriously alleging that all lithium batteries eventually ignite? You know Tesla batteries ignite at only 10% of the rate that gasoline engines ignite, and it’s only because the tech is new and the fire is so difficult to extinguish that every last damned Tesla fire makes the news. (Maybe not quite so much any more.) So yeah, ICE engines catch fire 10 times more often, and of course when they do, they’re much more likely to explode. And also, when only the engine catches fire, that’s not even a reported car fire. (My ICE engine caught fire once.)