Study Highlights Pathways to Rare-Earth-Free Electric Vehicle Motors

Highlights

• Researchers explore alternative electric vehicle motor designs that reduce reliance on rare earth elements from China.
• New motor technologies like induction and reluctance motors show promising performance gains without rare earth materials.
• REE-free motors offer potential for lower costs, reduced environmental impact, and decreased geopolitical supply chain risks.

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A new comprehensive review by Rangarajan et al. involving scientists from the United States, India and Japan examine the technological, environmental, and supply chain implications of replacing rare-earth-element (REE)-based electric vehicle (EV) motors with alternative designs. Permanent magnet synchronous motors (PMSMs) using neodymium and dysprosium currently dominate the EV landscape due to their high torque density and efficiency. However, their dependence on Chinese-controlled REE supply raises cost volatility, environmental concerns, and geopolitical risk.

First Author—EV Expert

The study, led by Dr. Shriram Srinivasarangan Rangarajan (opens in a new tab), surveys multiple REE-free motor technologies—including induction motors, synchronous reluctance motors, and switched reluctance motors—alongside ferrite-magnet designs and wound-field synchronous machines. It highlights innovations in motor topology, advanced control algorithms (e.g., field-oriented control, model predictive control), and thermal management strategies that can bridge performance gaps with PMSMs. Notably, permanent-magnet-assisted reluctance designs and optimized ferrite configurations are showing measurable gains in torque density, narrowing the historic performance deficit.

Implications

The findings underscore that REE-free propulsion systems could significantly reduce EV manufacturers’ exposure to critical mineral supply disruptions, cut raw material costs, and lower environmental impact from mining. They also align with industrial decarbonization strategies and national initiatives in the U.S., EU, and Japan to diversify away from China’s near-monopoly on REE processing.

Early commercial examples—such as BMW’s fifth-generation eDrive and developments at Oak Ridge National Laboratory (opens in a new tab)—demonstrate that high-speed, compact REE-free motors are moving from lab to market.

Limitations

Despite the progress, the review acknowledges persistent challenges. REE-free motors often face lower peak torque density, higher torque ripple (especially in switched reluctance machines), and greater control complexity. Thermal management is more demanding due to higher copper losses, and some alternative magnetic materials (e.g., MnBi, AlNiCo) still lag NdFeB in coercivity and remanence, requiring larger, heavier designs. Many performance claims are based on simulations or prototypes rather than large-scale production data, and lifecycle environmental benefits remain under-quantified.

Conclusion

Rangarajan et al.’s work positions REE-free EV motors as a technically feasible and strategically important direction, but one requiring continued R&D in materials science, rotor/stator design, and power electronics. For automakers and investors, the message is clear: as performance parity approaches, REE-free solutions could become a mainstream option—reshaping cost structures, mitigating geopolitical risks, and enabling more sustainable growth in the global EV market. But there is work to be done.

Citation: Rangarajan, S.S.; Shiva, C.K.; Collins, E.R.; Senjyu, T. Electric Vehicle Motors Free of Rare-Earth Elements—An Overview. Machines 2025, 13(8), 702. https://doi.org/10.3390/machines13080702 (opens in a new tab)

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