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):
- 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.
The Down Side: Batteries
EVs face significant battery-related challenges:
- 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.
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.
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