Rare Earth Elements Aren't as Vital to Hybrids and EVs as You Might Think

By · May 17, 2011

Rare Earth Mine

Last week, the House Armed Services Committee passed a new defense authorization bill that including language that would lay the groundwork for a national rare earth elements stockpile, similar to the Strategic Petroleum Reserve. So why is hoarding rare earths important to national defense?

Supporters of the measure cite concerns over China's temporary dominance of rare earths production and its recent moves to limit exports on the minerals, whose broad applications throughout tech and consumer goods markets would put Chinese firms at a distinct advantage should major supply shortages emerge down the road. Rare earth elements (REEs) are used in products ranging from ceramics to X-ray machines, and are notably present in hybrid and electric vehicle motors.

But lost in the hype surrounding REEs tends to be a simple fact that should bring some peace of mind to electric-drive fans: though most hybrids and EVs use rather large quantities of the rare earths in their motors or batteries, they don't necessarily have to.

Rethinking Electric Motors

Rare earths are most vital to two alternative fuel components: the electric motors used to drive a hybrid or EV's wheels, and the nickel-metal hydride batteries found in most mainstream gas-electrics.

The rare element neodymium is the most oft-mentioned threat to the electric-drive vehicle market. It's the magnet in so-called fixed-magnet motors, which make up the majority of motors used in modern battery-powered applications, including hybrids and EVs.

Tesla Electric Motor

Tesla uses no rare earths in its electric vehicle motors.

But a competing technology that was originally developed by Nicola Tesla (among others) has existed since the late 19th century, and has since been used in a number of electric vehicles including the EV1, Tesla Roadster, MINI E, Ford Ranger EV, and Think City.

Induction motors are distinct from fixed magnet motors in that they use aluminum or copper conductors to create electromagnetic fields—without magnets. This in turn allows them to be manufactured sans rare earths.

The drawback to induction motors used to be that they were difficult to control, but thanks to modern semiconductors, that's no longer the case. Variable frequency drives can now smoothly regulate the electromagnetic fields necessary to convert stored electrical energy into mechanical energy and power a car forward.

Developing such a system for a hybrid or electric vehicle can be a complex and expensive process, but that hasn't kept Tesla and Toyota from employing one in their forthcoming RAV4 EV collaboration. Tesla has always favored rare-earth-free induction motors because of their ability to provide big boosts of power when called upon, and because they work more efficiently with other components in the carmaker's powertrain design.

Toyota, fearing rising Chinese neodymium costs that threaten to impede several of Japan's biggest industries, has also been experimenting with induction motors—potentially for use in some of its more mainstream future hybrid and electric vehicles.

The Toyota Prius and Prius Plug-in currently employ a combination of both induction and fixed magnet technology. But thanks to rising rare earth prices, the neodymium that once cost the carmaker less than $50 per vehicle to use, now tops out at more than five times that amount—giving Toyota engineers ample reason to at least reconsider the design. (It should be noted Toyota and most other major vehicle battery manufacturers currently have fixed-price agreements in place with REE suppliers that should, for the time being, mediate the effect of rising prices on the sticker price of hybrids.)


Common in Hybrid Batteries, But Not EVs

Nickel-metal hydride batteries, which are used in gas-electrics like Toyota Prius and Ford Escape hybrids, use large quantities of the rare earth element lanthanum in their battery chemistries. (The Prius is believed to use at least 22 pounds of the mineral.)

Lanthanum exists in large quantities at a newly reopened mine in Mountain Pass, Calif., and at other pending sites in Australia and South Africa—though like other REEs, nearly all production is currently sourced in China. But for plug-in vehicles like the Nissan LEAF and Chevy Volt, Lanthanum is not an issue, since lithium-ion batteries rely on a different battery chemistry to their nickel-metal equivalents.

Of course, not all hybrids even have use for lanthanum. With the release of the 2012 Civic Hybrid, Honda will officially begin its switch to lithium ion for all electric-drive vehicles, including hybrids. Mercedes, Hyundai and GM are doing the same, primarily because lithium batteries are lighter and more powerful than nickel-metal. As the price of rare earths increases, that equation should prove to be even more beneficial.

The U.S. government also recognizes the advantages of rare-earth-free solutions, and announced recently that it will allocate $30 million in grants towards the development of alternatives that don't depend on the environmentally hazardous and increasingly costly minerals.

So although near-term shortages of rare earths could temporarily increase production costs for some hybrids and EVs, the important factor that gets ignored is that the technologies needed to eliminate REEs from the electric-drive equation not only exist, but are already being implemented.


· Dan Aris (not verified) · 5 years ago

Great article Zach
Induction motors are cheaper too! e.g.
See: http://www.transportation.anl.gov/pdfs/HV/14.pdf
table 5.7 p28.

· Priusmaniac (not verified) · 5 years ago

Further down the road the copper in the motor will also have to be replaced by conductive polymers like polyacetylene or other materials. In a few decades we should end up having the holy grail of room temperature superconductors in the motors.

· · 5 years ago

Fortunately, we don't have to wait for the holy grail. Copper-based electric motors are over 90% efficient already.

· Thomas | Electric Car (not verified) · 5 years ago

There are and will always be converns about the limitation of materials, however the past showed that there are several solutions and ways to substitute materials or to improve the technology in order to reduce the demand for some materials.

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