Recent developments in high energy density metallised electrode capacitor technology

Metallised capacitors have been introduced in some pulsed power applications including medical cardiac defibrillators and electromagnetic launchers, where relatively slow (millisecond) discharges are standard. The advantages of using metallised electrodes in such applications include higher energy density and longer life, greater reliability and reduced costs. Capacitive energy densities of up to 2.7 kJ/kg delivering 100s of Joules, and larger capacitors at somewhat reduced energy densities have been achieved at Maxwell Technologies Inc. Capacitors with energy densities of up to 1.5 kJ/kg in sizes ranging from 10s of Joules to 50 kJ and beyond are now available commercially. This paper compares metallised electrode technology to discrete foils and provide an understanding of the advantages and disadvantages of each in capacitor design. Finally typical applications for metallised electrode capacitors are described.