IDTechEx: despite efforts to reduces rare-earth use, percentage of permanent magnet-based EV motors rising
While there has been much publicity and technical development towards rare-earth reduction in vehicle motors, in practice the market is seeing an increase in the number of permanent magnet motors. The new IDTechEx report “Materials for Electric Vehicles 2020-2030” finds that in recent years, there has been an increased shift towards more permanent magnet-based motors: 2019 saw this increase to 82% compared to 79% in 2015.
Permanent magnet motors typically have better efficiency during normal driving conditions than their alternatives, this in turn can result in improved driving range. For this reason, says IDTechEx, Tesla has transitioned from using copper induction motors in the Model S and X to using a permanent magnet motor in the Model 3 and Y (although dual motor variants use an ACIM on the front for a performance boost).
Additionally, the Chinese electric vehicle market is the largest in the world and due to their control of the rare-earth supply, most Chinese vehicle models utilize permanent magnet motors.
Permanent magnets are typically made with rare-earth materials such as neodymium and dysprosium, which have a very geographically constrained supply chain. China accounts for the vast majority of rare-earth production worldwide and this has, in the past, led to huge price volatility. In 2011, after China restricted its exports of rare-earths, the price of neodymium and dysprosium rose by approximately 750% and 2000% respectively.
While these prices have settled, rare-earths also present environmental concerns. The ores that rare-earths are extracted from are often laced with radioactive materials such as thorium. Separating the materials requires huge amounts of carcinogenic compounds like sulfate, ammonia and hydrochloric acid. Processing 1 tonne of rare-earths can produce up to 2000 tonnes of toxic waste.
Some OEMs have reduced magnetic material in total and OEMs such as Nissan and Honda have reduced or eliminated the heavy rare-earth components such as dysprosium. However, despite the potential reduction per vehicle of materials such as neodymium, the overall increase in the global EV market will lead to an overall increase in the demand for rare-earth materials.