EVs are fitted with external warning sound emitters when driving at low speeds for just this reason. In fact, I think that while it's not currently a legal requirement to have this, it will be from either next year or the year after.
PS the picture above is almost certainly fake.
You need a specific type of generator to charge an EV like that - something to do with the sine wave, IIRC? Plus in any case, the car pictured is a BMW i3, which was likely to have its own internal petrol-powered generator known as a range-extender or REx, which in the event of running low on electricity charges the battery rather than driving the wheels.