As you already know if you’ve tried to chug your car up a hill on a really hot day, cranking the AC reduces fuel efficiency. In an electric car with a limited range to begin with, that's a big deal, and can mean shaving dozens of miles off the distance a vehicle can travel on a single charge.
One solution could be as simple as installing better windows — laminated glass topped off with an infrared-reflective coating, the same stuff you might install in your home to keep your heating and cooling bills down. Tests show the stuff can lower the interior temperature of a car on a hot day by up to 18 degrees F.
That means a cooler car on days when you leave it parked in the sun, but it could also mean the difference between making it to the next charging station or not.