Electric vehicles are coming out as alternatives to emission-ridden transportation but they currently face major drawbacks that hamper their widespread deployment. Among these are the high cost and limited power that their batteries can provide.
One alternative, according to researchers at Drexel University, are through the use of supercapacitors which are commonly used to run robots and back up computer storage systems.
Describing how they work, Yuri Gogotsi, professor of materials science and engineering, said supercapacitors serve as power storage devices that can deliver onboard electrical power in hybrid vehicles.
Batteries normally store energy in chemical form or through substances that can react to release electrical energy. But supercapacitors store energy in an electrostatic field, where electrical charge on two cathodes is simply piled up. Unlike conventional batteries for EV’s, they can be charged and discharged in a matter of a few seconds and can endure thousands of such charging cycles.
They are “ideal for energy-saving applications that capitalize on transient opportunities for recharging, such as energy capture during braking, and other actions that require power to be delivered in short bursts,” they said.
For buses, using this technology would help cut emissions by about 30 percent.
Professor Gogotsi stressed that supercapacitors have the potential to be a big player in the search for reliable green energy across the world, especially for transportation, as observed in Germany. In Mannheim, supercapacitors allow cable cars or trams to use 30 percent less energy than their counterparts in other cities.
“Supercapacitor technology is now deployed on Spanish and French trains and hybrid buses all over the world, on construction equipment such as cranes, and on garbage-collection trucks in the United States.”
With a number of potential uses, they are one of the few electronic components that have had a gradually growing market over the past years with rapid growth that is widely anticipated, said the professor.
While supercapacitors seem to be very attractive for E.V.’s, they remain subjected under further improvements. According to the U.S. National Renewable Energy laboratory, the power produced by these is available only for a very short duration, whereas their self-discharge rate is much higher than with conventional batteries. The challenge now is how to dissolve these barriers.
“There is no single perfect energy-storage solution, no one size fits all,” said Prof. Gogotsi. “A battery of the future may well be a battery-supercapacitor hybrid which combines the long lifetime, fast charging, and high power of a supercapacitor with the high energy density of a battery,” he said.