Although the most significant data to quantify the autonomy of an electric car is its battery capacity, there are other factors that also influence it. One of them is very important in the engine and its efficiency. For this reason, it is necessary to correctly choose the type of motor that is used in each model. A combustion engine converts only 30% of the energy into torque that drives the wheels. The electric motor is much more efficient, reaching, according to technology, up to a 90% (or even more).
Electric car manufacturers use different electric motor technologies, which are distinguished by theo type of current need and how it is generated he near the rotor is generated from it in the stator. The DC synchronous motors they are most used and in those who use them permanent magnets in the rotor Their biggest drawback is that it calls for work rare earthreducing the cost of handling expensive and complex products. In turn, compact motors arise, easy to control and easy to cool, since only its windings are in the stator. They are therefore suitable for small or medium-sized electric vehicles.
Or they are to them externally excited synchronous motorswhich are used, for example, by Renault. Instead of permanent magnets they use windings in the rotor and an external electric source to create a magnetic field in them. Their advantage is that they admit the power of these things, and therefore in each torque they are required time, which makes it more effective. On the other hand, the machines are bigger because of the extras that are needed.
What happened to Tesla?
They are another type of machine asynchronous or alternating current inductionSuitable applications for high power (including squirrel cages) are the following used ones Tesla’s Model S and Model X. In fact, Nikola Tesla, after whom the company owes its name, was the inventor of this machine. At the coming of the Lord Model 3 switched to permanent magnets. Finally, a change was made to start incorporating it into other vehicles as well.
The rotor is made of wheels. The magnetic field that is generated in it is the product of the slip or speed difference with respect to the rotation of the stator. The torque generated is proportional to this slip, which makes it more difficult to control the speed of rotation in them. This is not dictated by the speed of the standings, as in synchrony, but by the fall. It is a cheap motor, less efficient and powerful, durable and robust because it does not need external power or moving parts.
A new approach: the best of each typology
The Californian manufacturer made an important announcement about the technology of electric motors last Investor Day. Elon Musk claimed I do not create a motor magnet permanent (synchronous) that there is no need for rare earths (cheap). that is, the best of both worlds.
In periodic tablethe elements called the rarer earths, in the image glowing red, are the lanthanide groups, in addition to scandium and yttrium. Actually, contrary to what their name says, they are not rare. For example, neodymium resources are about two-thirds larger than copper. Its high price is due to the fact that its extraction and processing are very polluting and expensive.
Contrary to what many people think, pregnancies do not usually contain them. They are in motor magnets, and are widely used, because of their abundance; neodymiumwhich also acts on noisy and hard magnets. Dysprosium and Terbium are commonly used adjectives for neodymium magnets.
According to Tesla, between 2017 and 2022, it managed to reduce the use of rare earths in its engines by 25%, thanks to the increased capacity of the transmission, which allows to reduce the size of the engine. But this is not enough. The goal is to keep permanent magnets in your motors, but you don’t need rare earths to create them.
During his presentation, Tesla showed fall who compared the current use of rare earths in the Model Y permanent magnet motor with this new next-generation motor that requires none of them. In the quantities indicated in P., each material is identified, probably considering the information of trade secret that cannot be revealed. The first number is probably neodymium, and the other two are dysprosium and terbium. In the future machine, there is no meaning of the materials that should succeed them.
Until now, neodymium-based permanent magnets have been the standard for applications requiring high-power electric motors that are easy to control through electronics and durable. But, due to the demand from the car industry, the price of its parts has increased and finding a substitute in rare earths has become a necessity.
They haven’t been for the last decade investigations into the problems of other materials which could potentially be restored. Although Tesla has not specified which ones it plans to use, this announcement indicates that it is close to making a decision, or at least sees the possibility of a good solution in the near future.
