Solar cars (or solar vehicles) are a special type of electric vehicle that only get their power from the sun. They use solar cells on the surface of the car to produce electricity and the electricity makes a motor turn, and that turns the wheels. They are not useful for normal driving, but once built, they can drive all day and not make any pollution. There are also some solar-powered vehicles for unusual cases, like the first rovers on Mars.
Also, there are electric vehicles that can be charged from separate solar panels, and those panels can be as big as needed. This can work to power an electric car for most daily needs. But this is not called a solar car, since it doesn't have the solar panels right on the car.
There are now several competitions to see who can build the best solar-powered car. Some of these are for college students, some are open to anybody. It is not easy to build a good solar car. This is a good test of engineering skills, and helps improve the efficiency of cars and test solar equipment.
Media related to Electrically-powered vehicles at Wikimedia Commons