Ultracaps provide ultraboost

Whether you need an energy reserve or a short-term power boost, ultracapacitors can be an excellent alternative to batteries or other sources in UPS, electric-vehicle, braking-system, and industrial applications (see "Ultracapacitors deliver jolts of power," EDN, March 1, 2001, pg 42). A new trio of ultracaps from Ness Capacitor has an operating voltage rating of 2.7V, which gives them 30% greater energy density than 2.3V units. The capacitors, in 1700, 3500, and 5000F sizes, use porous carbon electrodes as a key to their high capacitance/size and weight ratios (Picture). The 5000F model, for example, has energy density of 5.8 Whr/kg with ESR of 0.4 mΩ while delivering 500A.

These ultracapacitors have power density that is approximately 10 times that of a comparably sized conventional chemical battery, and you can charge and discharge them more than 100 times faster than conventional units. In addition, they do not suffer from batterylike charge/discharge-cycle degradation and have been tested to 500,000 cycles with typical capacitance loss of less than 20% and ESR increase by a factor of two. The units measure approximately 130×100×40 mm. The 1700 F, 2.7V unit costs $110 (small quantities).

Ness Capacitor Co, +82-31-219-0682. www.ness.co.kr.