
341Lead–Carbon Hybrid Ultracapacitors andTheir Applications
both the self-discharge rate and the leakage current are reduced. It is accepted
that with an open circuit condition, the voltage loss (namely self-discharge)
arises due to a leakage current through parallel resistance (as per Ohm’s law).
Higher parallel resistance would lead to lower leakage current ow, thus
reducing self-discharge rates. In the case of AGM and gelled lead–carbon
HUCs, the gelled conguration exhibits more self-discharge than AGM, thus
giving higher leakage current and lower parallel resistance accordingly as
evident from Table 8.2. The difference in self-discharge ...