Temperature dependent large area breakdown strength of polymeric films

Polymer film capacitors represent some of the most pervasive devices used in electrical and electronic systems. With the rapid growing demands in electrification, understanding of the breakdown mechanism in polymer capacitor films is needed to improve their reliability and increase their energy density. While engineering breakdown field cannot yet be predicted from first principles, temperature dependent breakdown measurement is one of the most important way to study the breakdown mechanism in polymer film capacitors. Previously, very limited studies have been done on the temperature dependence of breakdown strength, especially on polymer films made with modern processing methods. In this study, large area breakdown strength of various capacitor grade polymer films was measured from -150 °C to 110 °C and the result was analyzed with Weibull distribution analysis. The result showed that breakdown strength generally increases when the temperature decreases. Various breakdown mechanisms are involved within different temperature regions. Further study is currently underway to fully understand the effects of structure, morphology, crystallinity and processing condition.