How do hybrid cars work?
One of the most symbolic and popular symbols of the "green" movement is the hybrid-electric car, known better as simply the hybrid car. These vehicles extend the functionality of traditional internal combustion engines by combining them with a battery-powered electric motor, which takes some of the work off the combustion engine's hands. This allows the cars similar performance to a comparable conventional car with a much smaller gasoline engine, and an overall increase in fuel efficiency. Contrary to what some people think, these hybrid cars do not need to be plugged in to charge up the batteries.

Hybrid car batteries
The on-board batteries in hybrid cars are recharged by capturing the kinetic energy created when using the brakes (commonly referred to as "regenerative braking"), and some hybrids use the combustion engine to generate electricity by spinning an electrical generator to either recharge the battery or directly feed power to an electric motor that drives the vehicle.