Development of Sustainable Slot Liners for 800 V+ Oil-Cooled Electrical Machines for Passenger Cars

This paper presents the development of a high-performance slot-liner solution based on thermoplastic PEEK Films tailored for the next generation of $800 ~\mathrm{V}+$ oil-cooled electric drive units in automotive applications. The work highlights the critical role of slot-liners as a fundamental component of primary insulation systems to enable the design of electric motors that achieve high efficiency and torque without compromising reliability. To meet the demanding dielectric performance requirements for $800 ~\mathrm{V}+$ e-motors, a material development study has been conducted. The results undermine the suitability of PEEK Films for high-voltage slot-liner applications upon meeting the oil compatibility and dielectric performance criteria for passenger cars and heavy-duty vehicles.