Replacing rare earth metals in EV motors 

Rare earth metals are main components in the EV motors of today. But to be dependent of the metals can be problematic both from a security political point of view as well as sustainability wise. Professor Sandra Eriksson, at Uppsala University, leads a SEC-funded project to replace the metals in EVs. 

Professor Sandra Eriksson, Uppsala University

The rare earth metals are basic elements with unique magnetic characteristics that are very suitable to use in motors of electric vehicles and other electronic devices, such as cell phones. But the metals are also problematic since there can easily become a shortage. This is a large risk for the manufacturers, since above 90 percent of new electric cars are relying on them. Another issue is that there are often problems related to the mining, such as radioactive material getting released in the process and that ground water gets polluted.  

Sandra Eriksson and her PhD student are therefore investigating in how to design electrical motors for electromobility that are rare earth metal-free.  

“The rare earth metals are considered critical by the EU, but in this project, we want to show that they can be replaced by other materials”, says Sandra Eriksson.  

One of the rare earth metal-free motors the researchers look into is one using ferrite magnets, which there is a great surplus of, as a replacement to the rare earth metals. They are much cheaper and more available, as they are made from iron oxide with some additional chemical elements. The downside is that they are much heavier and with a weaker magnetic field. 

“We need to change the design of the motor and compress the magnetic field. When doing this we also need to change the mechanics of the motor. These heavier magnets will raise issues concerning the mechanical integrity of the fast-spinning electrical motor. Our main results this far concern the integration of the mechanical and the electromagnetic design to keep as much magnetic flux as possible, while at the same time have a robust motor that can withstand fast rotation”, says Sandra Eriksson. 

The researchers have a close collaboration with Scania in the project. Later in the project, they will build a prototype together for further research. There is a long way to go before the rare earth metals are replaced, but Sandra Eriksson thinks many will move away from the metals due to all the risks in it. For instance, in the summer of 2011, the price of neodymium increased tenfold when China, who is the main exporter of the metals, placed an export embargo on the metal.  

“In the last 10 years it has become very clear that there is a great win in replacing the rare earth metals since the price has increased very much.  There is a danger in being too dependent of rare earth metals and if there is a way forward with ferrite magnets, many will be interested in it”, she says.