On the end of the charge cord, like seen on many hair dryers, would be one option. Since outdoor and garage outlets are supposed to have GFCI protection built in you shouldn't need to add it if you have a newer home. There are less options for 240 vac GFCI protectors, but they are available because they are used on hot tub installations.
So in the car, or on the wall?I just installed it in a sub panel in the garage, and ran it to a 240VAC outlet I install right next to the sub panel. I use one of those 240V/30A "generator" extension cords sold at Home Depot to plug in the car (I pull at most about 16A).