THE ELECTRIC VEHICLE

The greatest limitation to the impact of the electric vehicle on transportation remains the battery. Current lead-acid batteries have a shorter range and are considered heavy and bulky. Figures developed by TRW, Inc. estimate that a battery weight equal to half of the total vehicle weight is needed to provide unsonable urban driving cycles using current lead-acid batteries. The nickel-zinc batteries would allow a vehicle to provide an acceptable urban driving range with a battery weight of any 20%. The nickel-iron battery, also under consideration, has a longer potential service life, but a specific energy no greater than that of lead-acid cells. The lithium sulfide battery developed by Argonne Laboratories is considered to be a stronger possibility than the other prototypes. It would provide a range of up to 200 mi. between re-charges. However, its high operating temperatures creates both sealing and containment problems. The lead-acid, the nickel-zinc, and the nickel-iron batteries are thought to provide the range required to make the electric car a viable second car for multi-car households. The use of electric vehicles as light commercial vehicles (taxis and buses) in the city of London, have proven to be effective. Electronic solid-state choppers for controlling speed and regenerative braking are discussed, as well as the question of energy conservation and passenger safety.