PERFORMANCE TESTING OF SELECTED COMMERCIAL ULTRACAPACITORS

摘要

Ultracapacitors, because of their potential for high rates of charge and discharge, and high power capabilities, are being studied for use in premium power sources, battery-powered electronics, and as load-leveling power sources in electric vehicles. The U.S. Department of Energy has expressed renewed interest in their potential use in hybrid electric vehicles (HEVs). This paper will report on the results of performance testing of selected, recent generation commercial ultracapaitors. Recent models of commercial ultracapacitors from CCR Corporation (Japan), Maxwell Technologies Company (USA), NESS Corporation (Korea), Panasonic Industrial Company (USA/Japan), and SAFT (USA/France) have been tested using some of the test protocols as given in References 1 and 2. The constant-current charge/discharge test from 10 A to 500 A at test temperatures of-20℃, +25℃, and +50℃ was used to measure the charge and discharge capacitance, the charge and discharge equivalent series resistance (ESR), the charge and discharge energy density, as well as the (discharge energy/charge energy) efficiency as a function of test current and test temperature. The constant-current charge constant-power discharge test, conducted from 50 watts up to 675 watts (depending qn the capacitor rating), over a voltage range of (l/2)Vmax to Vmax (Vmax is the maximum rated voltage of the capacitor) at the three test temperatures was used to measure the specific energy of the capacitors as a function of specific power on a per weight and per volume basis. Leakage-current and self-discharge tests at the three test temperatures were used to measure the time dependence of the leakage current, and the self-discharge energy loss factor. Tests from the recent version of the PNGV Battery Test Manual (this program is now referred to as FreedomCAR) were also used during the testing of the ultracapcitors. The Low-Current Hybrid Pulse Power Characterization (L-HPPC) Test adjusted for the FreedomCAR Power Assist goals was used to determine the dynamic power over the ultracapacitor's useable charge and voltage range. From this test, the number of capacitors required to meet the FreedomCar, as of February 2001, power and energy goals for the Power Assist application in HEVs was determined for the capacitors.