Tesla Announces Rare-Earth-Free Motors

March 6, 2023

Inside EVs:

There’s already plenty of misinformation out there about EVs and the use of rare earth elements. Most often, the case against electric cars is focused on the lithium-ion battery, its potential for fire, the materials it’s made of, how and where they’re mined, and the list goes on and on. However, according to Electrek, while today’s EV batteries do use critical minerals, they typically don’t contain rare earth elements.

Rare earth elements are found in EV motors. Neodymium appears to be the most common and is used for strong magnets, which are present in DC permanent magnet motors. Other common rare earth elements in electric motors are Dysprosium and Terbium. Currently, Tesla uses such elements in its DC permanent magnet motors, but not its AC induction motors.

Tesla didn’t start using the DC permanent magnet motors until the Model 3 came to market in 2017. The company shared during its Investor Day event that since the Model 3 first arrived, it has reduced its rare earth element usage by 25%, all while increasing the motor’s efficiency.

Moving forward, Tesla aims to continue producing and using a permanent magnet motor, but it won’t require any rare earth elements. The image at the top of the page shows the next-gen motor’s “0” usage. Tesla also shared the following slide showing the current rare earths required for the motor in the Model Y:

Adamas Intelligence:

Rare earths: “going to be a little hard to meet that demand”

At Tesla’s 2023 Investor Day on March 1st the company revealed that its next generation PMSM traction motors would not use rare earth permanent magnets.

As stated by Colin Campbell, VP Powertrain Engineering at Tesla, “as the world transitions to clean energy, demand for rare earths is really increasing dramatically and not only is it going to be a little hard to meet that demand but mining that rare earth, it has environmental and health risks”.

Likely a ferrite magnet powered PMSM

While not stated during Investor Day, we expect the most likely candidate replacing NdFeB in Tesla’s next generation motor design is ferrite – it’s a proven concept.

General Motors’ second generation Voltec powertrain used in the 2016 Chevy Volt had a ferrite-driven PMSM alongside an NdFeB-powered PMSM. More recently, Proterial (formerly Hitachi Metals) unveiled its own EV motor designs using ferrite magnets (see December 2022 “EV Motor Materials Monthly”).

To-date, no perfect alternatives to NdFeB

While it’s been demonstrated that a ferrite-powered PMSM can match or exceed the performance of an NdFeB-powered alternative across one or more parameters, this performance comes with a significant weight or efficiency penalty that has historically made the switch unattractive.

For example, in one of Proterial’s new motor designs, it simulated an EV traction motor with ferrite magnets that matched the output and max rotation speed of a comparable PMSM containing NdFeB magnets, but is 30% heavier – a ‘massive’ weight penalty.

In Proterial’s second design, it simulated an EV traction motor with ferrite magnets that matched the output and motor weight of a comparable PMSM containing NdFeB magnets but operates at a 50% higher rotation speed, translating to a material reduction in torque.

In Tesla’s case, the articulated focus when it comes to motors has long been on maximizing the cost-performance balance, which is where NdFeB-powered PMSMs shine, so it is eye-opening to see the new motor concept being justified on the back of anticipated supply scarcity and “environmental and health risks”.

Not all rare earth production is equal when it comes to environmental and health impacts

On account of the Bayan Obo mine in China, along with the nation’s ionic clay mines and those of neighboring Myanmar, the rare earth industry as a whole is often referenced as the paradoxical postal child of electromobility and clean energy – and rightfully so, a decade ago.

Today, there are more supply options than just China/Myanmar and others on the cusp of starting production – options that are transparent, close to home (for Tesla in particular) and substantially less impactful on the environment than the China production of yesteryear.

Up-to-date life cycle impact assessments and comparisons of rare earth production from different sources are sparse, however, what is available suggests that the environmental and health impacts of non-China rare earth production is, or has potential to be, just a fraction of that in China.

For example, a 2018 study by Marx et al. found that the normalized environmental impacts of one kilogram of NdFeB produced from the Mountain Pass mine in the U.S. were around a third that of Bayan Obo.

Similarly, a 2016 study by Schreiber et al. found that production of neodymium and dysprosium (key inputs in NdFeB magnets) from Norra Kärr in Sweden can have just a fraction of the environmental and health impact of that same production from Bayan Obo.

Additionally, there are now more emerging rare earth magnet recyclers than ever before, several starting to produce at scale and with significant commercial traction, including Noveon, Cyclic Materials, REEcycle, Maginito, Innord, Ionic Technologies and others. These producers have potential to supply some of the cleanest rare earths on the planet, environmentally speaking.


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