High Dielectric Constant Polycarbonate/Nylon Multilayer Films Capacitors with Self-Healing Capability

Abstract

With the fast development of high-temperature metal oxide semiconductor field effect transistors for power electronics in electric vehicles, current state-of-the-art biaxially oriented polypropylene (BOPP) film capacitors need further improvement because they have a temperature rating of only 85 °C without derating the voltage to maintain a long lifetime. If a high-temperature polymer can replace BOPP without sacrificing the overall dielectric performance and cost, it is possible to remove the current water-cooling system for capacitors and significantly reduce the cost of the power electronic unit. In this work, we demonstrated new polycarbonate (PC)/nylon multilayer films (MLFs), which has a potential for even higher temperature rating because of the higher melting temperature for nylons (e.g., nylon-6). Structural and dielectric studies showed that these PC/nylon MLFs had a similar dielectric performance, such as dielectric constant, dielectric loss, and breakdown strength, as the PC/poly­(vinylidene fluoride) PVDF MLFs, which were developed in the past. These PC/nylon MLFs could perform well up to 120 °C, which was limited by the glass transition temperature of PC at 145 °C. More intriguingly, packaged PC/nylon-12 MLF capacitors exhibited a self-healing capability, which had been difficult for packaged high-temperature film capacitors. Because self-healing is such a fundamental requirement for polymer film capacitors, our PC/nylon MLFs offer a potential for next-generation high-temperature and high-energy density film capacitors.

Enhanced dielectric properties of sandwich‐structured biaxially oriented polypropylene by grafting hyper‐branched aromatic polyamide as surface layers

“…Very recently, the emergence of sandwich structures provides a new insight to solve the paradox between high E and high ε r in dielectric polymer composites. This technology makes it possible to fabricate high performance dielectric composites by integrating the advantages of several dielectric materials with quit different properties . More importantly, the dielectric performance of multilayer composites could be tailored by turning their structure, such as number of layers, layer thickness, and stacking sequences .…”

Electromechanical deformation and failure of multilayered films

“…The forced assembly multilayer coextrusion process enables many polymeric systems having unique architectures to be produced including multilayer films, 10 cellular film/foam materials, 11–14 and fibrous membrane systems 9,15–18 . In addition, there has been numerous studies on the multilayered coextruded polymer systems directed toward applications including gas barrier films, 8,19 optical films, 20 shape memory films, 21–24 packaging film/foams, 25 fibrous membranes for filtration, 18,26 antibacterial membranes, 27,28 cellular membranes having through pores 12 and multilayer films with unique dielectric properties 29–36 . These investigations have emphasized the importance of scale within the multilayer films relative to enhanced performance characteristics.…”

“…9,[15][16][17][18] In addition, there has been numerous studies on the multilayered coextruded polymer systems directed toward applications including gas barrier films, 8,19 optical films, 20 shape memory films, [21][22][23][24] packaging film/foams, 25 fibrous membranes for filtration, 18,26 antibacterial membranes, 27,28 cellular membranes having through pores 12 and multilayer films with unique dielectric properties. [29][30][31][32][33][34][35][36] These investigations have emphasized the importance of scale within the multilayer films relative to enhanced performance characteristics.…”

Deformation and failure of polycarbonate in an electric field

“…As the electric field increases, the prebreakdown damage occurs and eventually the material will breakdown. Researchers have focused on understanding and minimizing the dielectric loss, [19][20][21][22][23][24][25] but have paid little attention to the mechanical damage and prebreakdown phenomenon. Understanding the prebreakdown phenomenon of the dielectrics in solid capacitors in high voltage equipment is of great importance.…”