Advances in Lithium and Nickel-Metal Hydride Battery Performance

Abstract

Traditional batteries stored energy in thick plates made from heavy metals like lead, nickel, and zinc. They delivered from 15 to 20 Wh/kg. Lighter-weight lithium anodes were used in some military batteries. Then came the need for lightweight batteries for powering cellular telephones and laptop computers. Lithiumion batteries were developed, and the worldwide demand, just for use in laptop computers, has grown to 150 million units per year.The need to reduce air pollution in downtown areas has created a market for battery-powered electric vehicles. Clara Ford chose to drive an electric car, even though her husband, Henry Ford, was making gasoline-powered cars. However, the cost of replacing worn-out leadacid batteries soon ended the electric-car age of the early 1900s. The need for lightweight, long-life batteries for zero-emission cars has produced unprecedented investments in battery technology. The lithium-battery technology used in laptop-computer batteries did not support the requirements of high power and long life for the charge/discharge cycling needed in electric cars. An executive of a lithium-battery manufacturer was asked what he was doing about the cycle life of his batteries. His answer: “The life of a laptop computer is nine months. Then a newer model makes it obsolete. We meet this requirement!”