Capacitor tech talk Autumn 2009

1) Electrochemical capacitors are reported to offer higher cycle efficiency than batteries, even though their self-discharge rate is much higher. Isn't this a contradiction?

For any electrochemical energy storage device there are really two efficiencies of note, charge efficiency and energy efficiency. Charge efficiency, often called Coulombic efficiency, is defined in percent as 100 times the charge out divided by the charge in or, in other words, the ratio of charge out to charge in. For example, if 1 Ah charge is put into a device and upon discharge 0.95 Ah is returned, then the . . .