The World Book Bonus Science Reference

Electric Car

Electric car is an automobile powered by rechargeable batteries. The electric energy stored in the batteries is converted to mechanical power by means of electric motors.

Electric cars have four main advantages over gasoline-powered cars. (1) They produce no exhaust pollutants, and so their widespread use could reduce air pollution. (2) They use batteries, and so they do not consume increasingly scarce petroleum resources. (3) Electric cars are quiet, reducing noise in congested areas. (4) Their batteries can be recharged while the owner is at home or at work, and thus the owner can avoid the inconvenience of stopping at a service station to refuel.

The chief disadvantage of electric cars is that they can travel only about 100 miles (160 kilometers) before their batteries must be recharged. Some gasoline-powered cars can go about 500 miles (800 kilometers) before they need refueling. Also, the batteries for an electric car are very expensive and must be replaced two or three times during the life of the vehicle. In addition, because the batteries must fit into a small space, they can store only a limited amount of energy. As a result, electric cars have below-average acceleration, and most of them have a top speed of less than 62 miles (100 kilometers) per hour.

Another problem with electric cars is that the power required to recharge their batteries is generated at the same electric power plants that provide electricity for cities and towns. If electric cars were used extensively, the capacity of these facilities would have to be greatly increased. The increased capacity would contribute to pollution in areas around the plants.

How electric cars work. The electric car is powered by one or more electric motors. In most cases, the motors are coupled directly to the wheels. This system eliminates the need for a transmission. The driver uses an electronic controller to control the rate at which energy flows from the batteries to the motor or motors. Modern electric cars have many complex electronic parts. But they have fewer mechanical parts than do the gasoline-powered cars.

Power for an electric car comes from batteries that run one or more motors. The car can travel only about 100 miles (160 kilometers) before the batteries must be recharged.

From The World Book Multimedia Encyclopedia ©1998 World Book, Inc., 525 W. Monroe, Chicago, IL 60661. All rights reserved.

World Book illustration by William Graham.

History. The first electric cars appeared in Europe during the 1880's. They soon became popular in the United States. Americans drove more electrics than gasoline cars during the late 1800's. By the early 1900's, however, gasoline-powered cars had become more powerful, performed better, needed less refueling, and were cheaper to operate than electric cars were. The electric car had almost disappeared by the late 1920's.

In the 1960's, increasing concern about air pollution and dwindling supplies of petroleum renewed people's interest in electric cars. In the 1970's, limited production of electric cars resumed. However, sales of electric cars have remained low because of their high purchase price, their limited travel range, and their relatively poor performance. In addition, the lack of a battery that is inexpensive, powerful, durable, and lightweight has helped limit the car's success.

In the late 1970's and 1980's, manufacturers developed experimental electric cars known as hybrids. These cars have all the components of the electric cars plus an internal-combustion engine. This engine can be used to recharge the batteries or to drive the vehicle. In the late 1980's, one of the most technologically advanced electric cars was the Sunraycer, developed by the General Motors Corporation. This experimental vehicle used solar energy to recharge its batteries.

Contributor: William H. Haverdink, M.S.E.M., Staff Research Engineer, General Motors Research Laboratories.

 

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