Biaxial Stretching and Self-clearing Study of Multilayer Polymer Films for Capacitive Energy Storage
Abstract
For the past 18 years, the multilayer film (MLF) technology has been successfully developed at Case Western Reserve University, which holds good potential for Navy#s pulsed power and power conditioning capacitor applications. After years of effort to mitigate disadvantageous dielectric properties, we are now in a good position to compete with current biaxially oriented polypropylene (BOPP) films for dielectric capacitors. However, there are still several challenges before the commercialization of MLF capacitors. First, high quality ultrathin films are needed to compete with current BOPP films, whose thickness is down to 2-3 #m. To achieve this goal, we propose to biaxially stretch poly(ethylene naphthalate) (PEN)/ poly(vinylidene fluoride) (PVDF) MLFs, because PEN has excellent biaxial stretchability and good dielectric insulation up to 150 °C. Various biaxial stretching conditions will be explored to achieve successful biaxial orientation of the MLFs, including stretching temperatures, draw ratio, and draw rate. For the biaxially stretched MLFs, various structural analysis and dielectric characterizations will be performed to evaluate their high temperature performance. Second, self-clearing is an indispensable property for polymer film capacitors. However, the chemistry and physics of self-clearing are not well-understood. To tackle this task, we proposed to build a new sample fixture and test self-clearing at the stacked film level. Surface plasma treatment and plasma surface polymerization will be used to modify the surfaces of the MLFs and increase theoxygen content. Meanwhile, self-clearing physics will be understood using a thermal model for various high temperature polymer films, together with our MLFs. The ultimate goal is to achieve successful self-clearing for the MLFs and different high temperature dielectric films. The knowledge obtained from this project will greatly benefit future packaging of next-generation film capacitors withhigh energy density, high temperature tolerance, and low loss properties.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 11, 2023
- Source ID
- N000142312788
Entities
People
- Lei Zhu
Organizations
- Case Western Reserve University
- Office of Naval Research
- United States Navy