Next Generation of Supercapacitors

Super Charged

A tiny South Korean company is out to make capacitors powerful enough to propel the next generation of hybrid-electric cars

By Glenn Zorpette

IEEE Spectrum
NessCap is one of about 10 makers of ultracapacitors, devices that can store so much charge that they are beginning to blur the functional distinction between the capacitor and the battery. And according to some experts, nobody does it better than NessCap, which offers a unit rated at an impressive 5000 farads at 2.7 volts in a package a little bigger than a half-liter soda bottle. NessCap’s capacitors “perform as well as or better than any others we’ve ever tested, in terms of energy and power density,” says Marshall Miller, a research engineer at the University of California at Davis, where he specializes in testing advanced capacitors and other devices.
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On paper, anyway, the idea is not far-fetched. In comparison with batteries, ultracapacitors can put out much more power for a given weight, can be charged in seconds rather than hours, and can function at more extreme temperatures. They’re also more efficient, and they last much longer—in tests at the Idaho National Engineering and Environmental Laboratory, in Idaho Falls, upwards of 500 000 charge-discharge cycles have been recorded. Automotive traction batteries, for comparison, have much shorter lifetimes, particularly if they are discharged deeply.