This study aimed to investigate the feasibility of mixed use of super-capacitor and lead-acid battery in power system. The main objectives are as follow: The mathematical model is established on the basis of circuit analysis. Research the key factors affecting power system efficiency.
The result are as follows: The charging efficiency is higher when the super-capacitor is charged preferentially. Sequential charging is adopted, with stable current, small fluctuation and better battery protection performance. This study demonstrated the development and prospect of hybrid super-capacitor and lead-acid battery power storage system.
This battery operates in a state-of-charge range from 20% to 80% and provides very long cycle life and higher efficiency than standard lead-acid batteries. The battery combines the high-power capability of supercapacitors with the energy storage capacity of the battery, providing high capacity charge/discharge while increasing cycle life.
In contrast to secondary batteries, super-capacitors, also known as “electrochemical double-layer capacitors” (EDLC), offer higher power density and life cycle but have considerably lower energy density. Super-capacitors currently find use as short-term power buffers or secondary energy storage devices in renewable energy, power systems [ 12, 13 ].
A recent advance in lead–acid battery technology developed by the Australian Commonwealth Scientific and Industrial Research Organisation (CSIRO) is the UltraBattery, a hybrid energy storage device that integrates a supercapacitor with a lead–acid battery in one unit cell [11 ].
The lead–acid component comprises one positive plate (lead dioxide, PbO 2) and one negative plate (sponge lead, Pb). An asymmetric supercapacitor is formed when the lead negative plate of the lead–acid cell is replaced by a carbon-based counterpart (i.e., a capacitor electrode).