Quite a lot of electric cars will still have a lead acid battery for the low charge things like wipers, electric windows and electric mirrors. It's simpler to do that than to have a complicated system to step down the voltage to something they can accept from a lithium ion battery.

So essentially electric cars have two independent electrical systems that have nothing to do with each other. Interestingly this means that you can use an electric car to jump start an ICE car, even though a lot of people claim you cannot.

That said some electric cars do go the route of a step down transformer so check your car.