On the occasion of the event of Tesla streamed to investors last month – which proved lean on new announcements and rich in pompous storytelling – a minor detail of the new plan unveiled by Elon Musk for his company, the so-called Master Plan Part 3, caused a stir in an obscure niche of physics. Colin Campbell, an executive in the electric vehicle company’s powertrain division, has announced that the team plans him to eliminate rare earth magnets from car engines, citing supply chain problems and the toxicity of the production process as reasons.
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To emphasize the news, Campbell showed some slides that referred to three mysterious materials, labeled rare earths 1, 2 and 3. In the first slide, which represents Tesla’s current approach, the quantities of rare earths used range from one pound to ten grams. In the next, which represents thecompany objective for an unspecified futureall quantities are zero.
For magnetism experts, who study the forces exerted by some materials due to the motions of electrons, the identity of Rare Earth 1 was obvious: the neodymium. When added to more familiar elements, such as iron and boron, this metal can help create a strong, always-on magnetic field. However, few materials possess this quality, and even fewer are those capable of generating a field strong enough to move a two-ton Tesla. If the company has decided to eliminate neodymium and other rare earths from its motors, what kind of magnets would you use to replace them?
The role of rare earths
What is clear to physicists is that Tesla did not invent a new magnetic material: “We discover a new trade magnet a couple of times a century”, explains Andy Blackburn, executive vice president of Niron Magnetics, one of the few startups that is trying to find new magnets.
For Blackburn, but not only, it is more likely that Tesla has decided to settle for a much less powerful magnet. The obvious candidate among the various options, most of which are costly and geopolitically dangerous elements such as cobalt, was ferrite: a ceramic of iron and oxygen, mixed with a little bit of a metal, such as strontium. It is cheap and easy to produce and has been used to close the doors of refrigerators all over the world since the 1950s.
However, ferrite has a magnetic power equal to about one-tenth that of neodymium magnets in terms of volume, an aspect which naturally raises new questions. Tesla’s administrator Elon Musk is known for its unwillingness to compromisebut if the company does indeed go ferrite, the impression is that it will have to give up something (Tesla did not respond to a request for comment by Wired US).
It is often mistakenly thought that it is the battery that drives an electric vehicle, when in reality the merit lies with theelectromagnetism (it is no coincidence that Tesla the company, and tesla, intended as a unit of measurement of magnetism, are named after the same person). As electrons flow through the motor’s wire coils, they create an electromagnetic field that pushes against opposing magnetic forces, causing the motor shaft to rotate and the wheels to spin.
For the rear wheels of a Tesla, these forces are provided by a permanent magnet motor, materials that have the bizarre ability to have a constant magnetic field, without any electrical input, thanks to a well-orchestrated rotation of electrons around its atoms. Tesla only started adding these magnets to his cars about five years ago to increase the mileage and torque of his models without having to upgrade the battery. Previously, the company used induction motors built around electromagnets (still in use in front-engined models).
For this reason, the choice to say goodbye to rare earths by Tesla – thus giving up the best magnets around – it might seem a little weird. Generally, automakers are obsessed with efficiency, especially in the case of electric vehicles, which must try to convince motorists to overcome fears related to a limited range. But as companies begin to scale up production of electric cars, some technologies previously considered too inefficient are making a comeback.
Automakers, including Tesla, are producing more vehicles that have batteries made with LFP (lithium iron phosphate). These models tend to be lower-end than those with batteries that contain elements like cobalt and nickel. This is an older technology that is heavier and packs less energy. At the same time, however, from a commercial point of view, the choice may prove to be more intelligent, as it allows not to use expensive and politically risky materials.
However, it is unlikely that Tesla would simply replace his magnets with a far less efficient material, such as ferrite, without making other changes: “You’d end up with a huge magnet to carry around in your car“, points out Alena Vishina, a physicist at Uppsala University. Fortunately, an engine is a complex machine with many other components that, in theory, can be rearranged to compensate for the use of weaker magnets. Through computer modeling, materials company Proterial recently determined that by carefully positioning the ferrite magnets and tweaking other aspects of the motor, it was possible to replicate many of the performance characteristics of rare-earth-powered motors. In the case of Proterial, the result was an engine that was only 30 per cent heavier, potentially a tiny difference from the overall footprint of a car.
Geopolitics and environmental factor
Despite the headaches, they are there many reasons why it would make sense for an auto company to get rid of rare earths, if it is able to do so. Since the early 1990s, when Chinese leader Deng Xiaoping declared that they were the equivalent of Saudi oil to his country, these elements have become something of a keyword in the context of geopolitical anxieties trans-pacific. It matters little that rare earths are not really like oil: even if the total market for these materials is about as much as that of eggs in the United States and rare earths can in theory be extracted, processed and transformed into magnets anywhere in the world , the China it’s the only place to do that.
China’s near-monopoly is due in part to economic reasons – in the 1990s Chinese low-cost rare earths flooded the market, accelerating the closure of mines and processing in areas such as the United States – and partly to environmental concerns. The extraction and refining of rare earths is a notoriously toxic activity, also because the most precious elements, such as neodymium, are closely linked to other rare earths and to radioactive elements such as uranium and thorium. Today, China produces nearly two-thirds of the rare earths mined worldwide and processes more than 90 percent of the world’s magnets.
“This is a ten billion dollar industry, which allows you to achieve products that are worth between two and three trillion dollars a year. That’s a huge leverage“, says Thomas Kruemmer, mineral analyst and author of the popular blog Rare Earth Observer. The reasoning also applies to cars, although each vehicle contains only a few kilograms of rare earths. Without these materials, however, a car would not work, a unless you are willing to redesign the entire engine.
The United States and Europe are trying to diversify the supply chain. A California mine that closed in the early 2000s was recently reopened and now supplies 15 percent of the world’s rare earths, though the minerals are then shipped to China for processing. In the United States, government agencies – especially the Department of Defense, which needs strong magnets for equipment such as aircraft and satellites – have decided to invest in domestic supply chains and friendly regions such as Japan and Europe. But it is a slow process, destined to last for years or even decades, due to costs, the necessary know-how and environmental problems.
Meanwhile, the demand for magnets embedded in decarbonisation tools, such as cars and wind turbines, is increasing. According to Adamas Intelligence, currently 12% of rare earths go to electric vehicles, a market that is only now taking off. At the same time, Rare earth prices have recently soared due to China’s domestic markets and political interventions that external companies cannot always predict.
Hunt for the alternative
All in all, if an industry can find a viable alternative to their use, it probably makes sense to move away from rare earths, says Jim Chelikowsky, a physicist who studies magnetic materials at the University of Texas at Austin. But there are many reasons, Chelikowsky continues, to look better substitutes for ferrite. The challenge is to find materials that exhibit three essential qualities: they must be magnetic, retain magnetism in the presence of other magnetic fields, and tolerate high temperatures (hot magnets lose their magnetism).
Researchers have a pretty good idea of which chemical elements might make for viable magnets. Some magnet hunters have started from hundreds of thousands of possible materials, discarding those with drawbacks, such as the presence of rare earths, and then using machine learning to predict the magnetic qualities of those left. However, often the biggest challenge is to find new magnets that are also easy to make. Some of the new types, such as those containing manganese, are promising but also unstable, explains Vishina of Uppsala University. In other cases, scientists know a material is extraordinarily magnetic but can’t be created in large quantities. It is the case of tetrataenitis, a compound of nickel and iron that is found only in meteorites and needs to cool for thousands of years in order to arrange its atoms correctly. At present, attempts are underway to produce the material more quickly in the laboratory, but they have not yet borne the hoped-for results. Niron Magnetics is a little ahead, thanks to an iron nitride magnet that, according to the company, is theoretically more magnetic than neodymium. But even then it is a fickle material, difficult to produce and store in a desirable form. Blackburn says the company is making progress, but it won’t be able to produce magnets strong enough in time for the next generation of Tesla models. The first step, he adds, is to insert the new magnets inside smaller devices, such as audio systems.
It’s unclear whether other automakers will take a cue from Tesla’s rare-earth compromise, Kruemmer says. Some companies may continue to use them, while others may opt for induction motors or try something new. Kruemmer also believes Tesla will continue to use the material – at least a few grams – in its future vehicles, for components such as automatic windows, power steering and windshield wipers. Despite the alternatives rare earth magnets from China are here to stay, especially at a time when the world is pushing towards decarbonisation. It would be nice to be able to replace them altogether, but, as Kruemmer points out, “We just don’t have the time“.
This article originally appeared on Wired US.
