What is the difference between an electric car, a plug-in hybrid, and a mild hybrid?

An electric car runs solely on electricity and is charged through the power grid, with no petrol engine. A plug-in hybrid has both an electric motor and a petrol or diesel engine and can be driven a short distance on electricity alone. When the battery is empty, the petrol engine automatically takes over, and the battery can be charged from the power grid. A mild hybrid has a smaller electric motor that assists the petrol or diesel engine, for example during acceleration or start/stop, but it cannot run on electricity alone and is not charged via the power grid.

Read more here: What is the difference between a plug-in hybrid and an electric hybrid?