End-of-Life Electric Vehicle Battery Deep-Discharge Device Using Current Recirculation and Single-Phase Grid-Tied Inverter

It is projected that, by 2030, the global stock of electric vehicles (EVs) will reach approximately 85 million units. When the capacity of EV batteries declines to 70–80% of their original performance, replacement becomes necessary, as the remaining capacity is inadequate to meet the operational requirements of automotive applications. Upon removal, these batteries retain significant material value and thus require proper recycling. However, their stored energy presents substantial safety risks, necessitating a controlled discharge process to mitigate potential hazards. This study presents the design and implementation of a system that integrates a boost converter with a single-phase grid-tied inverter to facilitate the safe transfer of energy from end-of-life (EoL) EV batteries to the electrical grid. The system was simulated in PLECS using a lithium-ion battery model and a non-ideal grid. The analysis shows that the system is stable and effective at transferring energy from the battery to the grid and heating the battery at the end of the process. This study identifies circuit operating conditions and control schemes that can enable the rapid, practical, and safe discharge of EV batteries without significant voltage relaxation.