The future market for hybrid-electric vehicles, at least those that are affordable, isn’t necessarily paved with lithium. Researchers in Australia have created what could be called a lead-acid battery on steroids, capable of performing as well as the nickel-metal hydride systems found in most hybrid cars but at a fraction of the cost.
The so-called UltraBattery combines 150-year-old lead-acid technology with supercapacitors, electronic devices that can quickly absorb and release large bursts of energy over millions of cycles without significant degradation. As a result, the new battery lasts at least four times longer than conventional lead-acid batteries, and its creators say that it can be manufactured at one-quarter the cost of existing hybrid-electric battery packs.
In the United Kingdom last week, a Honda Insight hybrid powered by the UltraBattery system surpassed 100,000 miles on a test track. “The batteries were still in perfect condition at the end of the test,” says David Lamb, who heads up low-emission transport research at the Commonwealth Scientific and Industrial Research Organisation (CSIRO), Australia’s national science agency. “What we’ve got is a lead-acid battery that is nice and cheap but can perform as well as, or better than, the nickel-metal hydride technology, which we know is very expensive.”
Lead-acid batteries, invented by French physicist Gaston Plante in 1859, don’t get much respect these days, despite being a crucial fixture under the hood of most vehicles. They contain lead, so environmentalists don’t like them. They’re heavy for the energy they store–a bad trait for mobile applications. And they degrade easily if not cycled properly. Indeed, there have been no major advances in the technology over the decades.
Meanwhile, a newer generation of batteries–most notably lithium-ion ones–are capturing the attention of investors and automakers. “Many have tried to improve the lead-acid battery, but the improvements were usually not that great or worth the added cost,” says Malcolm Shemmans, founder and president of BET Services, a provider of battery-testing services to the auto industry.
To compensate for some of the shortcomings of lead-acid technology, many in the past have tried to complement the batteries with supercapacitors. In the late 1990s, for example, Lamb helped design two hybrid cars that used a 60-volt lead-acid pack and a separate 150-volt supercapacitor pack. The lead-acid system allowed the vehicles to drive in all-electric mode in the city, while the supercapacitors gave the cars the jolt that was needed for acceleration and the ability to quickly absorb energy from braking.