Rare earth magnets are a crucial component of electric motors in an electric vehicle (EV). According to IDTechEx, rare earth permanent magnet motors have retained a greater than 75% market share since 2015 thanks to their efficiency, power density, and manufacturing simplicity. Many will be aware of the concerns around rare earth materials, such as price volatility and environmental impact. Another is China’s dominance in its supply of processed materials. Much focus is placed on the battery supply and localization of production (and rightly so), but motor components are also critical.
One way to alleviate concerns is by adopting magnetic materials that do not contain rare earths. Based on IDTechEx’s latest research report on “Electric Motors for Electric Vehicles 2025-2035: Technologies, Materials, Markets, and Forecasts”, this article will cover some of the most promising alternatives and their trade-offs.
Key metrics for magnetic materials
A stronger magnet means a smaller, more efficient electric motor. Key properties of any magnetic material include:
- Maximum energy product (how much magnetic energy is stored)
- Magnetic remanence (magnetic intensity after the magnetizing field is removed)
- Coercivity (ability to resist demagnetization)
Ideally, these properties should be as high as possible. The most common form of rare earth magnet is neodymium iron boron (NdFeB). These possess strong performance in all three.
The alternatives
While there are many other magnetic materials, none can currently compete with NdFeB on all three metrics.
- Aluminum nickel cobalt (AlNiCo) magnets have strong remanence, but poor coercivity and maximum energy product. Cobalt is also an expensive and somewhat controversial material.
- Samarium cobalt (SmCo) magnets have comparable remanence and coercivity but poorer maximum energy product. Again, they contain cobalt which is not ideal.
- Manganese bismuth (MnBi) magnets lose much of their coercivity during manufacturing and the maximum energy product is still much lower than NdFeB.
- Ferrite magnets like iron nitride (FeN) typically fall short of NdFeB on all counts, but are abundant and cheap. They also allow for higher temperature operation, meaning the performance gap could be closed slightly when operating with a hotter motor.
Alternative magnetic materials can often compete on certain magnetic parameters, but generally not all of them. Source: IDTechEx
What has to be changed in the motor?
The most immediate change is the size of the magnets. Due to their poorer magnetic performance, the magnets need to be larger. A typical rare earth motor will use 1-2kg of magnets, for a ferrite motor, this figure would likely double or even triple. This creates a challenge in the rotor’s structural integrity as the magnets will make up a much larger proportion of the rotor, rather than the electrical steel.
Even with larger magnets, the performance of the motor would be very challenging to compare to rare earth motors, resulting in a larger or lower power motor. Rare earth magnets make up a large portion of a motor’s bill of materials (up to 50%, according to IDTechEx research). This might not be such a large concern for specific lower-performance use cases, and the material savings could outweigh the performance hit.
While other magnets can operate at higher temperatures without demagnetization, this might be a hard benefit to realize. As temperature increases the resistance in the conductors will also increase, reducing efficiency.
Players looking at alternative magnets for EV motors
Given the potential benefits of eliminating rare earths, several projects and companies are looking to provide solutions; a few examples are given below.
- Niron – iron nitride magnets with field strength approaching NdFeB. It has investors including Volvo, Stellantis, and GM.
- Proterial – previously Hitachi Metals, has publicized the use of NMF15 (ferrite magnets) that provide the world’s highest performance for ferrites.
- PASSENGER (Pilot Action for Securing a Sustainable European Next Generation of Efficient RE-free Magnets) – an EU project to develop improved strontium-ferrite, and manganese-aluminum-carbon alloys to enable permanent magnet production in Europe.
Could recycled magnets be a better alternative?
Given the limitations of alternative magnetic materials, one could consider using recycled magnets from end-of-life products. One key challenge is material supply. It will take a long time for enough EVs to reach their end-of-life to make a dent in the required materials for new EVs. There is also the challenge of recovering these materials given most electric motors are not designed for easy disassembly. Nonetheless, there are projects from players like Polestar, Advanced Electric Machines, Nissan, and other government projects looking to improve the recycling of rare earths. In the long term, the cost, efficiency, and feedstock for recycled rare earths could be suitable, but this is certainly not a short term solution to supplying the current demand.
Outlook for alternative magnetic materials
Despite the challenges, due to the uncertainty around material pricing and a general global drive to secure supply chains locally, IDTechEx is predicting growth in the EV market that uses rare earth-free magnets. If magnet-free motors (such as externally excited synchronous motors, EESMs) are included, then IDTechEx predicts that nearly 30% of the EV market will be using rare earth-free motors by 2035.
For more information and in-depth analysis on this topic, as well as a greater dive into the EV electric motor market, please see the latest IDTechEx report on www.IDTechEx.com/Motors.
