With China's blockade serving as a wake-up call, many companies are working on alternate motor technologies to reduce or eliminate the need for rare earth magnets.
19 Jul 2025 | 1202 Views | By Arunima Pal & Angitha Suresh
Electric vehicle manufacturers are accelerating their search for alternatives to rare-earth permanent magnet motors, driven by China's overwhelming control of the supply chain and mounting concerns about cost volatility and environmental impact. While rare-earth permanent magnet synchronous motors (PMSMs) still dominate over 80% of the EV market due to their ...
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Electric vehicle manufacturers are accelerating their search for alternatives to rare-earth permanent magnet motors, driven by China's overwhelming control of the supply chain and mounting concerns about cost volatility and environmental impact. While rare-earth permanent magnet synchronous motors (PMSMs) still dominate over 80% of the EV market due to their superior power density and efficiency, emerging alternatives are rapidly gaining traction as automakers seek to reduce their dependence on Chinese-controlled materials.
Technical Alternatives
Induction motors: Tesla's proven path induction motors represent the most mature alternative to rare-earth PMSMs, operating on electromagnetic induction principles without permanent magnets. Tesla pioneered their use in EVs with the original Roadster and Model S, achieving 85-95% efficiency depending on operating conditions. These motors generate a rotating magnetic field in the stator that induces currents in the rotor's copper or aluminum bars, creating torque through controlled slip.
Performance characteristics include excellent starting torque and robust construction, though they suffer from inherent slip losses that limit maximum efficiency. Tesla's Model S induction motor achieved over 90% efficiency in optimal regions while delivering 430 Nm of peak torque. The technology offers 20-30% lower material costs compared to rare-earth motors and eliminates supply chain vulnerabilities, though power density remains lower at 1-3 kW/kg versus 3-5 kW/kg for PMSMs.
Switched reluctance motors: Simple but challenging, switched reluctance motors (SRMs) operate on variable magnetic reluctance principles, with both stator and rotor featuring salient poles. The rotor aligns with energized stator poles to minimize magnetic reluctance, creating torque through sequential switching. This design eliminates all permanent magnets and rare earth materials, using only steel laminations and copper windings.
Technical advantages include exceptional fault tolerance, wide operating temperature ranges, and the simplest construction among motor types. Manufacturing costs can be 40-60% lower than rare-earth motors, making them attractive for cost-sensitive applications. However, SRMs face significant challenges including 10-30% torque ripple, acoustic noise, and complex control requirements. Recent research focuses on advanced control algorithms and optimized switching strategies to mitigate these issues.
Wound-field synchronous motors: Controllable magnetism Wound-field synchronous motors (WFSMs) replace permanent magnets with electromagnetically excited rotor windings, enabling precise control over magnetic field strength. This approach offers 90-96% efficiency with superior field-weakening capabilities compared to PMSMs. Recent prototypes demonstrate 7.19 kW/L volumetric density and torque density of 17.22 Nm/L, approaching PMSM performance levels.
The technology provides variable torque capability through field current control and eliminates rare earth dependency, though it introduces rotor complexity and field winding losses. Manufacturing costs are potentially 15-25% lower than PMSMs, but thermal management of rotor windings remains challenging.
Externally excited synchronous motors: BMW’s fifth-generation eDrive marks a breakthrough, showcasing externally excited synchronous motor (EESM) technology, featuring current-excited synchronous motors with no rare earth elements. Implemented in the i4, iX, and i7 models, these motors achieve superior efficiency at high speeds compared to PMSMs while offering precise magnetic field control.
Performance benefits include up to 4% higher efficiency than PMSMs in certain operating conditions and 30% performance improvement over previous generation motors. The technology eliminates coasting losses associated with permanent magnets and provides enhanced regenerative braking capabilities. However, field winding losses at low speeds and increased control complexity present ongoing challenges.
New Innovations
The landscape of rare-earth-free motor technology is rapidly evolving, driven by breakthrough materials and novel designs. Niron Magnetics has developed revolutionary iron nitride magnets from abundant iron and nitrogen, achieving performance equal to rare earth magnets while reducing costs by 50% and weight by 40%. The company secured $33 million from GM Ventures and Stellantis Ventures in 2023, with commercial production planned for 2025.
ZF's I2SM technology represents another significant advancement, integrating inductive excitation within the rotor shaft to eliminate brushes and slip rings. This design achieves 15% lower energy losses compared to conventional excited synchronous motors while requiring 50% less installation space.
The technology demonstrates comparable torque density to PMSMs without rare earth dependency. Axial flux motors are gaining prominence for their exceptional power density, achieving 7-12 kW/kg compared to 3-5 kW/kg for traditional radial flux motors. Mercedes-Benz's YASA subsidiary targets 220 kW in a 7 kg package, representing a 31 kW/kg power density that significantly exceeds current PMSM capabilities.
Industry Adoption Strategies
Automaker strategies vary significantly in their approach to rare earth alternatives. Tesla, despite pioneering induction motors, has transitioned to all-permanent magnet motors across its current lineup while announcing plans to eliminate rare earth elements from future drive units. The company reduced rare earth usage by 25% between 2017- 2022 and is exploring ferrite magnet alternatives. BMW leads EESM adoption with current production implementation across multiple models, demonstrating the technology's commercial viability.
Renault pioneered EESM technology in 2012 with the ZOE, producing approximately 426,000 units before transitioning to nextgeneration platforms. General Motors employs a hybrid approach with its Ultium platform, combining a 62kW induction motor for AWD assist with rare-earth-minimized permanent magnet motors.
The company's partnership with Niron Magnetics and MP Materials demonstrates a dual strategy of supply chain diversification and alternative technology development. Toyota focuses on heavy rare earth elimination, achieving rare-earth-free magnets in its latest Camry hybrid by substituting expensive dysprosium and terbium with more abundant lanthanum and cerium. This approach reduces material costs from $100/kg to $5-7/kg while maintaining performance.
While rare earth PMSMs maintain performance leadership with 93-95% peak efficiency and 10-12 kW/kg power density, alternative technologies offer compelling trade-offs. Wound-field synchronous motors achieve 90-96% efficiency with 15-25% cost reduction in materials. Induction motors provide 20-30% lower material costs with 88-92% efficiency.
Switched reluctance motors offer the greatest cost savings at 40-60% reduction while accepting 85-90% efficiency. The economic analysis reveals that alternative technologies benefit more from manufacturing scale effects, with projected 15-25% cost reductions through learning curves by 2030. Current material cost advantages are substantial—ferrite magnets cost 10-20 times less than rare earth magnets, while steel and copper provide more stable, diversified supply chains.