It has a certain effect.
After being exposed to the scorching sun for one hour, the temperature inside the car without a sunscreen is higher than that with a sunscreen. This shows that sunscreen still has a certain effect.
It is also illegal to install parasols on electric vehicles. According to relevant legal regulations, the height cannot exceed 1.5 meters from the ground, the width cannot exceed 0.15 meters on the left and right sides, the front end of the length cannot exceed the wheels, and the rear end cannot exceed 0.3 meters. Under normal circumstances, electric vehicles equipped with parasols violate this regulation.