High Voltage Super-Capacitors for Energy Storage Devices Applications

Super-capacitor has the characteristics of big capacitance, high energy density, long cycle life, quick charge and discharge compared with traditional capacitors, which is regarded as a new-style energy storage element. The general demands for super-capacitors are high working voltage, big capacitance and low resistance for pulse power supply applications, especially for the pulse power supply of electromagnetic launch system applications. However the working voltage of existing super-capacitors is very low (<3.5 V), which has restricted its further applications. To meet the requirements of high voltage, it has to be connected some units of super-capacitors in series. But the total capacitance of energy storage device decreases, and the inner resistance increases. In the paper, a high voltage super-capacitor of 100 V, 5.8 mF, 0.05 Omega was introduced. The super-capacitor is composed of anode of electrolytic capacitors, cathode of electrochemical capacitors and 38 wt% H₂SO₄ electrolyte solution. By electric test, the super- capacitor has the properties of large capacitance and high energy density, which is an idea energy storage element. Energy storage device of 100 V/3 kJ is constructed with 100 high voltage super-capacitors in parallel; it can be set between battery and pulse load as intermediate energy storage device instead of electrolytic capacitors to enhance energy density and power density of power supply system. The test and simulation results show that the energy storage device can provide a discharge current of 2000 A, and peak power up to 200 kW.