Life cycle assessment of electric traction induction machines

Geopolitical challenges, coupled with the expected surge in demand for electric vehicles (EVs), may create uncertainties in the supply of rare-earth elements (REEs) used in permanent magnet synchronous machines (PMSMs), the predominant type of electric traction machine (e-machine) in EVs. This life cycle assessment (LCA) study benchmarks an REE-free alternative machine type, induction machine (IM), against a classic PMSM with REE magnets for EV application. Three IM variants are evaluated: one with copper (Cu) stator windings and Cu rotor bars, one with Cu stator windings and aluminum (Al) rotor bars, and one with Al stator windings and Al rotor bars. Beyond a baseline setup, the study also explores strategies to reduce GHGs, including using green virgin Al and enhancing the material utilization rate during the punching process for electrical steel sheets, referred to as a “green manufacturing” route. Furthermore, a sensitivity analysis of GHGs on magnet production is also conducted. The results show that the PMSM causes the least greenhouse gas (GHG) emissions due to its higher power density and efficiency. In contrast, the IMs with Al conductors exhibit lower environmental impacts in the categories of toxicity and acidification compared to those with (more) copper. The sensitivity analysis shows that IMs have the potential to display lower carbon footprints than PMSMs under favorable conditions. The research highlights the environmental trade-offs in e-machine design for EVs. The study underscores the need for a sustainable perspective on e-machine materials and manufacturing processes. It demonstrates that REE-free IMs, particularly when paired with green manufacturing strategies, can be competitive alternatives to PMSMs in terms of environmental performance, depending on design and production choices. Compares rare-earth-free induction machines with permanent magnet machines. Aluminum-based induction machines show lower toxicity and acidification. Green manufacturing and material choices reduce greenhouse gas emissions. Sensitivity analysis shows induction machines can have lower carbon footprints. Highlights environmental trade-offs in electric machine design for vehicles.