Electric cars are really still in their infancy. And, like infants, they've been really terrible about picking coherent standards to do things as a collaborative whole. Put any group of babies together and ask them to establish norms for, say, a standard unit of density, and what do they do? Wet themselves and shove things in their mouths. Way to go, assholes.
The electric car-making companies aren't much different. There really should be a standard for charging voltage/amps and the physical plugs, but that's a way off. So you'd think there'd at least be one for the symbol for the charging port. Nope!
There's sort of a consensus, usually involving a little stylized plug. And, generally, since that's how we tend to get power to things, that works. What doesn't work is what Smart's doing here, on their Smart ForStars show car.
It's a gas can with a lightning bolt.
This is wrong on a few levels. First, it initially implies gasoline. In a can. Gas in a can is the emergency way we get gas, when we're stuck on the side of the road, generally. Plus, the car, being electric, doesn't, you know, use any gasoline. Sure, you could fill it up with gas, but you'd have to fill up the interior, and that's only fun for Viking funerals and that sort of thing.
So, to alter the gas can to suggest electricity, they've got a lightning bolt on the gas can. Yes, the bolt does suggest electricity. And, it's used to indicate charging on our phones and other devices often. It's also the most dramatic way to get a crapload of electricity into things, very rapidly and destructively. Also, fun fact: it can't be stored in cans.
Maybe I'm being too harsh. You can look at this symbol and I think get the general idea of what's going on, so it works in that context. Maybe I owe the Smart an apology.
Until I think about pouring a can of lightning in the taillight-port of this thing.