Electric car: batteries and the issue of rare earths

Electric car: batteries and the issue of rare earths Auto

Electric car: batteries and the issue of rare earths

In the media and on social networks, the ecological footprint of electric vehicles is regularly singled out. The use of “rare earths” in batteries, in particular, is the subject of debate. Between rumors, untruths and realities, let’s take stock.

Rare earths are not rare!

Rare earths (TR) are not actually earths, but metals and they are not rare! It is in fact the name of a family of 17 chemical elements from the famous Mendeleev table that all high school students have one day come to know. The most widely used are cerium (40.2% of the RE consumed), lanthanum (27.8%) and neodymium (17.6%). Be careful not to mix everything up: some other metals such as lithium and cobalt used in lithium-ion batteries are not rare earths. Although they sometimes cause controversy as well, their issues are not at all the same and we will not address them in this dossier.

Contrary to what their name might suggest, the abundance of rare earths in the earth’s crust is much greater than that of many other metals in common use: their concentration is three times greater than that of copper and twice more than that of zinc, two metals however widely used in industry and present in many goods in common use. Rare earths, for example, are 200 times more abundant on earth than gold or platinum. In other words, the exploitable reserves of rare earths are much less critical than those of many other strategic metals.

Their family name “rare earths” comes from the fact that they were discovered at the end of the 18th century in ores (hence the name “earths”), uncommon at that time and difficult to separate. from each other with the techniques used at the time.

A resource distributed to the four corners of the planet

Historically the first rare earth operations in the 1940s were located in Brazil and India. After the discovery in the 1950s of large deposits in South Africa, this country was the main producer until the early 1970s when new mines were opened in the United States (Mountain Pass deposit) and in Australia in particular . And then, in the 1980s, China started producing rare earths, and practiced price dumping which ultimately led to the closure, for lack of profitability, of the other major world operations. In the early 2000s, the Chinese had a virtual monopoly on production with a market share of almost 90%. Then they decided to reduce their export quotas which caused a rise in prices and the opening or reopening of new mines in the world, in the United States (California), in Australia, in Sweden, in Brazil, in Vietnam, in Russia… Very recently (end of 2017), one of the richest deposits on the planet, that of Gakara in Burundi, came into operation. In Brazil, a German-funded pilot project, under the aegis of the University of Clausthal, is studying the possibility of recovering rare earths from tailings from phosphate farms.

Contrary to what one can read here and there in certain media and on the net, China, although still the world’s leading producer of rare earths does not hold the majority of reserves: only 30 to 40% of between them according to estimates. Brazil (with reserves estimated at 22 million tonnes, more than half of those of China), India, the United States, Canada, Greenland, Russia, Australia, Africa South, Vietnam, Thailand and several countries in East Africa, in particular, have significant deposits. The map below shows the distribution of the main rare earth deposits on the planet. As we can see, the resource is much better distributed than many others.

Electric car: batteries and the issue of rare earths

In 2018, the United States Institute of Geological Studies (USGS) estimated the world reserves of rare earth oxides to be 130 million tonnes, with an annual production that year of 170,000 tonnes. A little quick calculation allows us to understand that at the rate of current consumption we have therefore for … more than 750 years! Even in the event of strong growth in demand, there is something to “see ahead”.

First truth to be restored: rare earths are not at all rare, world reserves are large, well distributed over the 5 continents and no shortage is to be feared for a very long time. If China has a majority share of production it is only because it is dumping prices. But the growth in demand has started a reversal of the trend and many new mines are opening around the world.

The use of rare earths

If, at the start of their exploitation, rare earths were used to make lighter stones, refractory alloys and dyes for terracotta objects, production soared from the 1960s with their use in cathode-ray tubes. color televisions. Today, their electronic, magnetic, catalytic, optical, luminescent and mechanical properties make them the vitamins of the technology industry. They are used, for example, in flat screens, energy-saving lamps, LEDs, lasers, radars, computer hard drives, turbojet fins, heat pumps and air conditioning installations, refrigeration applications, certain photovoltaic panels, glass polishing, certain types of electric motors, as catalysts in petroleum refining, the petrochemical industry and catalytic converters in vehicles with thermal engines… In short, in a very large number of applications industrial.

More than a quarter (26%) of the rare earths used worldwide are used as catalysts in the petroleum industry and in catalytic converters in cars with combustion engines. Their use in the manufacture of permanent magnets for electric motors is the other most consuming application (20 to 23% of uses). The advantage of rare earth magnets is that the volume and weight required for equivalent magnetic performance is much less than that of magnets made with other technologies. They thus allow an interesting miniaturization for electric micromotors in automobiles (window regulators, mirrors, adjustable seats, etc.), computers, hard disk read heads, etc. Good to know: in every household rare earths are used in the engines equipping our refrigerators, vacuum cleaners, washing machines, dishwashers and other household appliances.

There are no more rare earths in electric vehicle batteries

About fifteen years ago, the first hybrid vehicles, in particular the Toyota Prius and the Honda, were equipped with NiMH (Nickel Metal Hybrid) batteries whose negative electrode (anode) was made of a lanthanum-pentanickel alloy. (LaNi5). These first-generation hybrid vehicle batteries contained around ten kilograms of lanthanum, which is indeed a rare earth. But today this battery technology is outdated: it has been replaced by the family of lithium-ion (Li-ion) batteries with much higher performance. While some hybrid Toyota models sold in Europe are still an exception by still being equipped with NiMH batteries (but this should not last long), the vast majority of hybrid and electric vehicles are now equipped with Li-ion batteries … which do not contain rare earths. Of course, they contain lithium, cobalt and nickel, but as indicated above, these metals are not rare earths and do not pose the same problems.

The engine of some electric vehicles contains rare earths

There remains the case of rare earths present in the engines of certain electric cars, mainly hybrids which must house an electric motor next to a heat engine and where the space criterion is therefore more important. Neodymium, dysprosium and samarium are the rare earths most used to manufacture the permanent magnets which equip brushless synchronous motors. But we can very well do without! Just assign the role of magnets to an excitation coil. Models such as the Renault Zoe (the most sold in Europe) or the Tesla Model S and Model X, for example, use this technology and their engine therefore does not contain rare earths. Others too, probably: we have not checked the engines of all the models currently in circulation. The important thing is to understand that electric cars can do without rare earths and that some, including the best-selling ones, hardly contain any. With the possible exception of rare earths that could be found in micromotors such as window regulators and wipers, which are not specific to electric vehicles.

In other words, the future and development of electric mobility does not depend on the exploitation of rare earths. On the other hand, the refining of petroleum and the catalytic converters of thermal cars, which themselves cannot do without rare earths, are among the biggest consumers. Like many household, technological or industrial appliances which, strangely, and unlike electric vehicles, have never been singled out for this “vice”.

Ecological impact

In the imagination conveyed by certain media in need of emotions or in search of the buzz that will drive up sales, the extraction of rare earths in Chinese quarries inevitably leads to an ecological and health disaster. And the culprit is obviously the electric vehicle. Showing a photo like this is always a sensation:

Electric car: batteries and the issue of rare earths

As we know, China has never shone for the ecological management of its industrial expansion. Its coal mines, power plants, heavy industry, waste management cause environmental disasters and countless premature deaths. That its rare earth quarries are no exception is no surprise. However, should we accuse electric vehicles of being the source of these ecological impacts when we know that they only use a tiny part of the rare earths produced in the world and, in addition, a list established in 2017 by the EU shows that only 40% of rare earths imported into Europe come from China; the United States (34%) and Russia (25%) sharing the balance. Blaming the environmental problems posed by China’s rare earth mining on electric vehicles is as absurd as accusing the railways and metro of producing radioactive waste because they use electricity produced by nuclear power plants. .

As shown in the photo below illustrating rare earths mining in the United States, it is quite possible to extract and produce rare earths while meeting strict environmental and health standards.

Electric car: batteries and the issue of rare earths

The situation is also changing in China: since December 2016, the Beijing authorities have inspected more than 400 companies active in the extraction and processing of rare earths and closed many illegal mines.

Another truth to be restored: the ecological impact of rare earth quarries in China is in no way attributable to electric vehicles.

Source: www.automobile-propre.com

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