Axial motor with recycled rare-earth material - ORNL
As some of the world’s largest automakers ramp up production for a generation of electric vehicles, the supply of one of the most important ingredients—rare-earth elements—is surely a cause for concern.
Rare-earth elements—especially neodymium—are in short supply because of their limited production locations, much of them in China. They're needed for the compact, power-dense permanent-magnet motors in many of today's EVs, and increasingly for green-energy sector uses like wind farms.
Now, researchers at Oak Ridge National Laboratories are experimenting with mining one of our best sources of rare-earth materials—used computer hard drives—for what can be repurposed in an axial gap motor, a type of permanent-magnet synchronous motor that could be used in electric vehicles or industrial machinery.
It’s just a demonstration so far, but it shows how magnets from devices that are otherwise destroyed could be recycled and reused as part of a circular economy.
Efforts to reduce rare-earth element use, as well as efforts to reuse and recover rare-earths, are frequently mentioned in sustainability reports. Toyota recently announced a way of cutting the neodymium in motor magnets by 20 percent (or up to 50 percent eventually) by substituting cerium and lanthanum, rare-earths that are processed simultaneously but aren’t as high-demand. And Nissan has, with its e-Power hybrid system slated for more models soon, boasted that it’s cut rare-earth elements by 70 percent.
Meanwhile, the appetite for rare-earth elements isn’t showing any signs of cooling. While Tesla went with AC induction motors for its Model S and Model X, it’s moved to a permanent-magnet design to power the rear wheels of the Tesla Model 3. Dual-motor all-wheel-drive versions of the Model 3 get an AC induction motor at the front that’s free of additional rare-earths. Likewise, Volkswagen has said that it’s planning to use permanent-magnet motors for rear motors in millions of new-generation electric vehicles arriving in the U.S. starting in 2020. Audi stands as an outlier, as at both axles it’s using a current-excited synchronous motor design that needs no rare-earths.
Volkswagen MEB platform architecture
The supply pinch is nothing new. Two decades ago, the U.S. was a significant producer of rare-earth elements, as was Australia. Eventually China inched into the market and corporations went out of business as they couldn’t match the prices on the Chinese-sourced material. That’s left China with an uncomfortable monopoly on the world’s supply, especially as the electronics and automotive sectors have been increasingly dependent on these materials.
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The fragility of the situation was demonstrated in 2011 when China cut off supply of rare-earth elements after a political tiff with Japan. Prices skyrocketed, sending users rushing to stockpile the materials initially, before prices tanked and set off some vicious volatility in recent years.
The researchers say that by simply recycling the 35 percent of hard drives that currently are destroyed, about 1,000 metric tons of magnet material could be recovered per year. While they made no statement about how many vehicle motor magnets that might support, every little bit will surely help.