PC Copolymer Film Bests PET and PEN in EV Capacitor Applications

Posted by Staff | May 11, 2023

Compared with other high-heat materials, such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), Sabic's Elcres polycarbonate copolymer–based HTV150A films reportedly can reduce dissipation losses by as much as 40% when exposed to temperatures reaching 150°C and frequencies up to 100 kHz. The material has already proven its mettle in thin-wall capacitor films.

Lower dissipation losses in Elcres HTV150A dielectric films can reduce internal heat generation, increase operating efficiency, and stabilize hot spot temperatures, giving engineers greater flexibility in designing capacitors. Lower losses in these films are expected to translate into reduced dissipation losses in capacitors.

"In developing Elcres HTV150A films, Sabic researchers drew upon their deep understanding of how polymers respond to thermal and electrical stress fields," said Ed Kung, senior manager, Resin Design and Incubation. "They selected material compositions with mild dissipation mechanisms in the temperature and frequency ranges of interest and have achieved impressive results. As customers design new inverter systems and adopt next-gen silicon carbide power modules, lower dissipation losses at higher operating temperatures and frequencies can help drive success."

Sabic is working with Japanese consulting firm Machine Technologies to study, test, and validate the performance of Elcres HTV150A films in DC link power capacitors for electric vehicle (EV) power train inverters. This ongoing collaboration has confirmed the value of Elcres HTV150A films in supporting hybrid, plug-in hybrid, and battery electric vehicle (xEV) technology.

Recent data from tests on single sheets of film conducted at the Sabic Polymer Processing Development Center in Pittsfield, MA, indicate that, in contrast to the way other high heat-materials respond, Elcres HTV150A films exhibit sharply reduced internal dissipation losses when exposed to high frequencies and temperatures. Importantly, these Sabic dielectric films can operate at temperatures up to 150°C, enabling DC link power capacitors to withstand disruptive hot spot temperatures. Competitive high-heat films such as PET and PEN are limited to operating temperatures below 125°C because they demonstrate increased dissipation losses above that point. The Elcres HTV150A films also retain dielectric properties through desired temperature and frequency ranges.

"Sabic and Machine Technologies collaboratively support customers by applying a rigorous methodology to test and validate capacitor materials," said Dr. Tsuyoshi Kasebe, CEO, Machine Technologies. "Data generated through this process can inform capacitor makers about the capabilities of Elcres films compared to other high-heat materials. As the industry transitions to power transistors based on silicon carbide and other advanced technologies, this data can be valuable in guiding new capacitor designs."

Elcres HTV150A dielectric films are the first in the industry to provide stable performance at operating temperatures between -40° and 150°C and frequencies up to 100 kHz, while offering stable capacitance, high insulation resistance, and good dielectric performance. They address the critical performance gap experienced by traditional polypropylene (PP) films above 105°C.

Capacitors built with 3- and 5-µm metalized Elcres HTV150A films pass standard electrical and life tests at 150°C for 2,000 hours with low capacitance change and stable insulation resistance. Other key properties cited by Sabic include high breakdown strength over the full temperature range, good self-healing, and excellent adhesion to aluminum and zinc during metallization. The film has been validated by customers for use with both film-foil and metalized electrodes.

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