Meeting report: Part I--Battery developments

Advanced Battery Technology, Feb 2001 by Oman, Henry

16TH Annual Battery Conference on Applications and Advances

January 9-12, 2001 Long Beach, California

The world has demonstrated a need for lightweight cell phones and computers, lighter electric cars, and hybrid vehicles that deliver100 miles per gallon of gasoline. These needs have produced highly motivated and well-financed development programs in batteries, fuel cells, and energy management. Each January the Annual Battery Conference on Applications and Advances brings together electrochemists, battery manufacturers, and engineers who use batteries to power loads that range from heart defibrillators to space stations. As a result, the 385-page Proceedings of the 2001 Conference contains 76 papers that report contributions from 177 authors.

The California State University Long Beach supplied the meeting room and the exhibit space in the student union building. Professor Radhe S. L. Das from the University's electrical engineering department has served as general chairman of every one of the 16 Conferences. Every year adds to his experience-base, and a learning curve no longer applies! For example, the November/December issue of Long Beach Today tells how you will "quickly learn that its location tops most lists for reasons that include a nearperfect climate, quintessential `California Dreaming' lifestyle...." However Prof. Das's predictive skills caused him to add to the advanced program this note under Attire: "Campus casual or suit yourself. But, remember to bring rain gear and accessories." Starting on the second day of the Conference came a downpour that broke all records since 1983!

Solution to California's Urban Air Pollution: Batteries in Electric Vehicles

People are dying from air pollution generated by highpowered cars that slowly creep on California's urban freeways during rush hours. However, financial reports of the successes and failures in the American automobile industry indicate that the factors entering into a typical consumer's new-car selection decision are these: (1) The effectiveness of the manufacturer's advertising and the dealer's salesmanship, (2) the short-time prestige and admiration that comes after a new car is purchased, (3) the thrill in one's body from being pushed by the force from high acceleration, (4) the price that has to be paid for the car, (5) popular features such as engine horsepower and displacement, (6) guarantees such as free repairs during a designated period of time, (7) gasoline consumption, and (8) exhaust emission control.

Intense research and development is now directed toward reducing urban air pollution, and the key is batteries. Nickel-metal hydride batteries are already in the Toyota Prius hybrid electric car. The latest reported improvements in the charge/discharge cycle life of lithium-based batteries indicate that these batteries also can become useful in lowemission hybrid electric vehicles.

An important development described at the conference can eliminate the premature capacity loss failure-mode of sealed lead-acid batteries. Charge/discharge cycle lifetimes of over 1000 are in sight. The present-day lead-acid batteries deliver around 40 watthours per kg. Three authors predicted specific energies of over 8OWh/kg. Furthermore, the lead-acid battery can deliver over one kW of power per kg and can be charged to nearly full capacity in a few minutes.

As a result, the lightweight nickel-metal hydride and lithium batteries will probably be used in nations where consumers seek low fuel consumption. Lead-acid batteries may be the choice of those United States consumers who have been buying cars that feature high horsepower, squealing tires during start, and rapid acceleration to a cruising speed. Consequently, the Lead Acid Battery Consortium is pushing development of lead-acid batteries for electric vehicles, particularly for pure-electric cars that can be quickly refueled with power from electric utilities.

HEVs vs. Grid-Connected All-Electric Vehicles

A grid-connected electric vehicle carries batteries that deliver its propulsion power. This vehicle produces no urban air pollution while it travels. The battery is charged at night with off-peak power that is available from the generating stations that power the electric-utility grid. Combinedcycle power-generating plants operate at efficiencies of up to 60%, and produce far less air pollution than comes from fuel-burning automobile engines that produce propulsion power. In evaluating the options for electric powered automobiles Tayor Moore analyzed these options: (1)

* An electric vehicle is propelled by an electric motor that gets its energy from an on-board battery that is recharged with power from a local power source.

* A grid-connected hybrid carries a small gasoline engine and generator for recharging the on-board battery. The engine is used only to extend the driving range or to provide extra power.

A hybrid electric vehicle is propelled by an engine plus a battery-powered motor. The engine's power level and running duration are continuously managed to minimize fuel consumption and maximize battery life.