Technique for Increasing the Energy Density of Capacitors

The availability of energy storage capacitors with high energy densities (>1- kJ/kg AND >15 MJ/m3) is critical for many applications. existing capacitor designs use laminated assemblies which are impregnated with liquid dielectrics. However, since the dielectric strength of liquids is generally much less than for solids, the maximum operating electric field is limited by the impregnant. This, in turn, limits the attainable energy density. The objective of the proposed phase i project is to determine the technical feasibility of the R-CAP concept. This is expected to substantially increase the energy density of existing capacitor designs through the use of a novel solid impregnation process. the R-CAP-CAP concept builds on the large amount of work already performed by capacitor developers. It offers the potential to extend energy densities by factors of >5 quickly and with minimal investment. The proposed phase I tasks are to: (1) impregnate and test capacitor windings of conventional high energy density design to demonstrate the efficacy of the R-CAP concept; (2) make preliminary variations in the impregnant and processing parameters with the objective of increasing the energy density by more than a factor of two; and (3) develop plans for optimizing the R-CAP technique with the most advanced existing capacitor designs. The Phase II goal will be to increase the energy density by factors of >5 for large energy storage capacitors. Energy storage capacitors manufactured using the R-CAP technique are expected to offer higher energy densities, longer life and higher reliabilities than possible with existing capacitor fabrication methods. This will be valuable for numerous government and commercial applications including: (1) electrothermal guns; (2) lightweight lasers and microwave generators; and, (3) space systems.