High temperature - High energy density polymer-coated glass capacitors

Traditional polymer capacitors used for pulsed power and power electronics applications have severe limitations in terms of portability and high temperature reliability. Alkali-free glass is a promising material for high temperature and high power capacitors because of its low dielectric loss and high breakdown strength (10 MV/cm), resulting in energy density values higher than 35 J/cm
³
. Thin glass sheet production has grown substantially because of the strong demand from the flat panel display industry and a large investment in the development of new glass fabrication methods. Several alkali-free glass compositions, such as Schott's AF-45 and NEG's OA-10G barium-boro-alumino-silicate glass, are commercially offered with a permittivity range of 5 to 7 and low dielectric loss (tan δ < 0.5%) values up to temperatures of 200°C. Glass ribbons and sheets are available with thicknesses between 5 and 50 µm and length of up to a few meters.