Electric vehicles (EVs) are propelled by an electric motor (or motors) powered by rechargeable battery packs. Electric motors have several advantages over internal combustion engines (ICEs):
The Down Side: Batteries
- Energy efficient. Electric motors convert 75% of the chemical energy from the batteries to power the wheels-internal combustion engines (ICEs) only convert 20% of the energy stored in gasoline.
- Environmentally friendly. EVs emit no tailpipe pollutants, although the power plant producing the electricity may emit them. Electricity from nuclear-, hydro-, solar-, or wind-powered plants causes no air pollutants.
- Reduce energy dependence. Electricity is a domestic energy source.
- Performance benefits. Electric motors provide quiet, smooth operation and stronger acceleration and require less maintenance than ICEs.
EVs face significant battery-related challenges:
Researchers are working on improved battery technologies to increase driving range and decrease recharging time, replacement frequency, weight, and cost. These factors will ultimately determine the future of EVs.
- Driving range. Most EVs can only go 150 miles (or less) before recharging-gasoline vehicles can go over 300 miles before refueling.
- Recharge time. Fully recharging the battery pack can take 4 to 8 hours.
- Battery cost: The large battery packs are expensive and usually must be replaced one or more times.
- Bulk & weight: Battery packs are heavy and take up considerable vehicle space.