High Temperature, High Energy Density Film Capacitors

The production of long life, light weight, high-volumetric-energy-density, high-voltage bus capacitors, which are stable at temperatures over 250oC, would enable the electrical systems of electric vehicles to operate at a higher temperature, making them ready for next generation SiC based components. The key to producing smaller, lighter, and temperature-stable capacitors is an improvement in the capacitor dielectric. Specifically, properties such as dielectric strength, temperature stability, and dielectric constant need to be improved over traditional materials. This project will investigate the use of flexible amorphous hafnium dioxide films as a dielectric for the fabrication of non-polar-wound high-volumetric-energy-density capacitors. Such amorphous oxides can have a dielectric constant greater than 25, breakdown strength in excess of 400 V/micron, and the flexibility needed to allow them to be rolled into various compact shapes. These properties make them ideal for improving the temperature stability, durability, and weight of the high voltage bus capacitors found in electric vehicles. Commercial Applications and other Benefits as described by the awardee: In addition to the market for electric vehicles, the improved dielectric material should enable the development of a new generation of compact, high-voltage, temperature-stable capacitors for military applications, including the conversion of prime electrical energy into the short pulses needed to energize loads such as directed energy and kinetic energy weapons and high power microwaves. Temperature-tolerant capacitors also could be used in conjunction with wide bandgap materials for the next generation of high temperature electronics.