High temperature polymer capacitors for aerospace applications

Abstract

Due to the need for reducing system size and weight while increasing performance, many military and commercial systems today require high-temperature electronics to run actuators, high-speed motors or generators. Of the many passive devices required to satisfy the needs for a complete high temperature system, none has been more problematic than the capacitor, particularly for larger devices requiring values of several micro-or milli-farads. Here we introduce a polymer metal composite we have recently developed that meets typical aerospace design constraints of high reliability, robustness, light-weight, as well as high temperature (up to 300°C) operation.Our recent discovery of the capacitive behaviour in perfluorinated sulfonic acid polymers sandwiched between metal electrodes has lead to the exciting development of high temperature capable high density passive storage components. These composites exhibit capacitance per unit planar area of ~1.0 mF cm -2 or 40 mF/g for a ~100 µm-thick polymer substrate, with only a small predictable decrease in capacitance immediately after heating to 100°C followed by constant capacitance up to 300°C. Here we report the design and testing of single step microfabrication of metal electrodes to these polymer composites sandwiched between two thin metal films along with their performance at high temperatures.

Evaluation of poly(4‐methyl‐1‐pentene) as a dielectric capacitor film for high‐temperature energy storage applications

“…Apart from PET and PVDF, alternate polymer chemistries are also being explored to find a suitable match to the capacitor industry requirements such as those of high‐energy high‐temperature dielectrics (>200 °C) . Poly(ether imide) (PEI), poly(phenylene sulfide) (PPS), polyacrylamides, poly(ethylene naphthalate) (PEN), poly(carbonate) (PC), poly(tetrafluoroethylene) (PTFE), and poly(sulfone) are few of those polymers that have been studied.…”

“…Apart from PET and PVDF, alternate polymer chemistries are also being explored to find a suitable match to the capacitor industry requirements such as those of high-energy hightemperature dielectrics (>200 8C). 3,14,[16][17][18][19] Poly(ether imide) (PEI), poly(phenylene sulfide) (PPS), 14 polyacrylamides, 16 poly(ethylene naphthalate) (PEN), 17 poly(carbonate) (PC), poly(tetrafluoroethylene) (PTFE), and poly(sulfone) 18 are few of those polymers that have been studied. However, compared to BOPP, most of these polymers suffer from limitations as described above for PET or PVDF, or provide comparable energy densities but with poorer mechanical and thermal properties so that BOPP is still considered to be a superior dielectric.…”

Practical Considerations for Designing Reliable DC/DC Converters, Applied to a BIPV Case

“…Next to switches, capacitors are one of the components that are prone to failure in power electronics applications. For high temperature applications, it is stated as the most troublesome component [38]. An excellent overview of the reliability aspects of DC link capacitors is given in [39].…”

Temperature dependence of SiC thin film metal-insulator-metal (MIM) capacitors on alumina over a temperature range from 25 to 500ºC

“…Aromatic polyureas fabricated through CVD have a stable dielectric constant up to 200ºC and can be used for high temperature energy storage capacitors [5]. In aerospace applications, a 100 µm thick perfluorinated sulfonic acid polymer sandwiched between metal electrodes exhibit a 1.0 mF/cm 2 capacitance per unit area and nearly no decrease in capacitance up to 300ºC [6]. Silicon dioxide MIM capacitors have been used in high temperature circuits, such as oscillators with chip antennas up to 250ºC, wireless pressure sensor system up to 300ºC and oscillators with spiral antenna up to 470ºC, with very little change in dielectric properties [7][8][9].…”