Traditionally, electric traction motors use permanent magnets made with rare-earth metals. However, materials such as dysprosium and neodymium are a limited resource. In addition to their rarity, extracting and processing these materials has environmental consequences, leaving behind a significant amount of toxic waste.
And, since China accounts for the vast majority of rare-earth production, logistics and price volatility are another challenge facing electric vehicle manufacturers. The volatile supply of neodymium—the main rare-earth metal used in electric motors—means there’s a good chance that its price will continue to skyrocket.
For instance, from February 2020 to February 2022, the cost of neodymium rose by 312 percent, with 1 kilogram costing more than $236, compared to $42 just two years ago. This type of extreme price fluctuation can make it difficult for manufactures to scale up production of EVs.
To make electric motors without rare-earth metals more sustainable, engineers at the University of Pittsburgh are working with Ames Laboratory and Powdermet Inc. to explore alternatives. The R&D initiative recently received $200,000 in funding from the U.S. Department of Energy.
“Permanent magnets are used in electric motors because they can produce and maintain a strong magnetic field, even in the presence of an opposing magnetic field, as opposed to electromagnets, which require an electric current,” says Paul Ohodnicki, Ph.D., associate professor of mechanical engineering and materials science at Pitt.
“Using alternative materials, such as [manganese-bismuth alloys] developed at Ames Laboratory’s Critical Materials Institute, to create a permanent magnet instead of using rare-earth metals like neodymium and dysprosium would make electric vehicles more affordable, accessible and sustainable, and would help the U.S. become a leader in the EV market,” claims Ohodnicki, who also serves as director of the Advanced Magnetics for Power and Energy Development (AMPED) consortium.
In addition to Pitt, AMPED includes engineers from Carnegie Mellon University and North Carolina State University who are investigating magnetic materials for power electronics and power conversion systems.
“Rare-earth metals have very unique magnetic properties that make them extremely effective as permanent magnets in high efficiency and power-dense motor designs,” explains Ohodnicki. “Our research is not actively developing new permanent magnet materials with reduced or eliminated rare-earth metals, but we are collaborating with other research groups that are working in this area to understand how alternative materials can be used in optimized motor designs.
Read more: Pitt Engineers Explore Next-Generation Electric Motor Technology