Virtual Development of Kinetic Energy Recovery System to Improve BEV Range in Cold Conditions 2020-01-5112

The automotive industry is undergoing a paradigm shift toward electrification, with battery electric vehicles (BEVs) at the focal point. BEVs are driven by a completely different set of design requirements compared to conventional vehicles with internal combustion engines (ICE), and optimization of such systems requires a systematic and holistic approach that leverages multi-domain, multi-physics methodologies.

Litens developed a predictive system model for an industry-leading BEV, the 2018 Tesla Model 3 Long Range version, and identified technologies that would enhance the vehicle performance and improve its drive range, especially during cold conditions in which BEVs are known to lose up to 60% of its range.

The Kinetic Energy Recovery System—Thermal (KERS-T) was developed as a result of extensive virtual engineering and analyses. It converts vehicle kinetic energy during braking events to thermal energy that can be readily used to rapidly warm up the system. A Phase Change Material (PCM)-based thermal battery was integrated to improve the controllability of the energy conversion process, as well as the overall system energy efficiency. Based on vehicle operating conditions and states, the KERS-T can be precisely controlled to allow for a seamless transition to the existing brake regeneration, which would charge the battery and improve vehicle range. Via the model, KERS-T demonstrated a reduction of active heating energy demand by 75% at a temperature lower than −5°C, resulting in an 18% range improvement. Besides, the system is flexible in that the control strategy would be selectable on demand by the end user to maximize either the system heating or the drive range.