Ceramic-polymer composite capacitors for compact pulsed power applications

The U.S. Department of Defense vision for future weapons systems requires the development of electrical pulsers that exceed current state-of-the-art in energy storage density by an order of magnitude or more. Alternatives to conventional wound polymer film and single layer ceramic capacitors are needed. Composite dielectric materials consisting of ceramic nanoparticles in a polymer matrix show promise for attaining the desired increase in energy storage density. Attributes of the polymer (high dielectric strength) and the ceramic (high dielectric constant) can be attained in a single composite dielectric material. Further, fabrication approaches involving casting of the composite offer opportunity for unique form factors, reliable and low cost manufacturing. TPL Inc. and colleagues have teamed to investigate the limits of these new materials for use in high energy density and high power capacitor designs. This paper reports on the development progress of the composite dielectric capacitors for high voltage (50 kV-Class) and high power (>10 MW/J) application. Sub-microsecond pulse discharge life as a function of the charge voltage is compared for four design iterations. Changes in the dielectric formulation, design and manufacturing process have yielded a 1,000x improvement in pulse discharge life and refinement of other critical capacitor characteristics.