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Enhancing Dielectric Properties of Multilayer Polymer Films for Next-Generation Capacitor Applications

Ju, Tianxiong
http://orcid.org/0000-0002-9694-0915
http://rave.ohiolink.edu/etdc/view?acc_num=case1685569814864338

Abstract Details

2023, Doctor of Philosophy, Case Western Reserve University, Macromolecular Science and Engineering.
Polymer film capacitors are suitable for capacitive energy storage in the expanding market of electric vehicles and high-speed trains, as their advantages of high electric breakdown, long lifetime, and high ripple current tolerance. The state-of-the-art polymer capacitor material is biaxially oriented polypropylene (BOPP), due to its ultralow loss, long operating lifetime, and high breakdown strength. However, its temperature rating of ~85 °C limits its application in electric vehicles since the ambient temperature, where DC-link capacitors are installed, is around 140 °C. Multilayer technology has proved its potential to achieve high energy density, high breakdown strength, and high-temperature rating simultaneously. These multilayer films (MLFs) are composed of a high temperature/low loss polymer and a high dielectric constant polymer. Under extreme conditions (e.g., high electric fields and high temperatures), an important loss mechanism of AC electronic conduction occurs in MLF capacitors by homocharge injection at the metal electrode/polymer interfaces and subsequently charge recombination, leading to heat generation. In this dissertation, this mechanism was studied for high temperature polycarbonate (HTPC)/poly(vinylidene fluoride) (PVDF) MLFs with either HTPC (MLF@HTPC) or PVDF (MLF@PVDF) as the outer skin layers. Based on DC/AC breakdown strength, DC lifetime measurements, and electric displacement-electric field loop analysis on metal electrode/MLF/metal electrode capacitor devices, it is concluded that the charge injection can be largely minimized when aluminum is used as the metal electrode material and HTPC is used as skin layers. In addition, the Tg effect of three PC MLFs was also studied by dielectric breakdown, lifetime, and leakage current measurements. From the experimental results, we conclude that charge injection was largely reduced with HTPC MLFs, leading to significantly enhanced insulation properties with high breakdown strength and long lifetime.
Lei Zhu (Committee Chair)
Geneviève Sauvé (Committee Member)
Gary Wnek (Committee Member)
Eric Baer (Committee Member)
246 p.
Energy; Plastics
Dielectric, Polycarbonate, PVDF, Energy storage, breakdown, lifetime, energy loss

Recommended Citations

Citations

  • Ju, T. (2023). Enhancing Dielectric Properties of Multilayer Polymer Films for Next-Generation Capacitor Applications [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1685569814864338

    APA Style (7th edition)

  • Ju, Tianxiong. Enhancing Dielectric Properties of Multilayer Polymer Films for Next-Generation Capacitor Applications. 2023. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1685569814864338.

    MLA Style (8th edition)

  • Ju, Tianxiong. "Enhancing Dielectric Properties of Multilayer Polymer Films for Next-Generation Capacitor Applications." Doctoral dissertation, Case Western Reserve University, 2023. http://rave.ohiolink.edu/etdc/view?acc_num=case1685569814864338

    Chicago Manual of Style (17th edition)

case1685569814864338
© 2023, some rights reserved.Creative Commons License Enhancing Dielectric Properties of Multilayer Polymer Films for Next-Generation Capacitor Applications by Tianxiong Ju is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.