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2024

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Toyota's latest magnet has a major structural adjustment, or will get rid of dependence on China's rare earth resources

Neodymium iron boron magnet (NdFeB) is a kind of permanent magnet with small size, light weight and strong magnetism. It is widely used in hybrid electric vehicles, wind power generation and robots and other emerging industries. The most critical material for NdFeB magnets is neodymium (Nd), an expensive rare earth element. Therefore, the price of neodymium can directly affect the profits of many downstream industries. Toyota said recently that for high-energy applications such as motors, it has successfully invented a magnet with only a fraction of the neodymium content of standard NdFeB magnets, which is expected to break the dependence on neodymium. For neodymium, a rare earth element, although increasing demand is leading


NdFeB magnet(NdFeB) is a small, light, and magnetic permanent magnet. It is currently widely used in many emerging industries such as hybrid vehicles, wind power generation, and robots.The most critical material for NdFeB magnets is neodymium (Nd), an expensive rare earth element. Therefore, the price of neodymium can directly affect the profits of many downstream industries. And Toyota recently said,For high-energy applications such as motors, a magnet with only a fraction of the neodymium content of a standard NdFeB magnet has been successfully invented, which is expected to break the dependence on neodymium.

For neodymium, a rare earth element, although the increasing demand is leading to a gradual increase in its mining, it is still very"Rare. Toyota has said:"With the increasing sales of electric vehicles such as hybrid and pure electric vehicles in the future, we are worried that there will be a shortage of neodymium supply.

In addition, China's dominance in the rare earth market is also very worrying for foreign companies downstream. SuchThe "rare earth crisis" in 2011 led to a substantial increase in the price of rare earth elements such as neodymium. Therefore, for Toyota, which relies heavily on neodymium to produce new energy vehicles such as the Prius, it is vital to get rid of its control of the Chinese rare earth market.Toyota's new magnet doesn't even need terbium or dysprosium, which are often added to neodymium magnets to improve its performance.Operability above 100 degrees Celsius.

The advantage of NdFeB magnets is thatVery large magnetic fields can be generated with very small volumes. After the addition of dysprosium, the neodymium iron boron magnet will also have a very high coercivity, that is, the resistance to magnetic field decline after magnetization.

Permanent magnet AC motors used in electric vehicles (In PMAC), NdFeB magnets are usually embedded in the rotor and driven by the magnetic field generated by the energization of the wires in the motor stator. In other designs, the magnets may also be embedded in the stator or driven by a DC electromagnetic field.In contrast, more common induction motors do not have any magnets and rely only on the magnetic field generated by electromagnetic induction through wires in the stator to drive the rotor.

Because permanent magnet motors can rely on the magnetic field of internal neodymium iron boron magnets, they tend to be smaller and lighter. For hybrid vehicles that require both a motor battery system and an internal combustion engine, it is important to reduce the size of the motor. Therefore, the vast majority of hybrid vehicles will use permanent magnet motors. And as a pure electric car TeslaModel S and Model X chose to use a heavier copper coil induction system. However, it is said that Model 3 has also turned to permanent magnet motors to reduce volume and weight, two parameters that are directly related to cruising range (and permanent magnet motors have stronger acceleration capabilities). In addition, the Chevrolet Bolt also uses a neodymium magnet motor.

In Toyota's new magnets, Toyota chose to use cheaper lanthanum and cerium instead of neodymium and dysprosium. Of course, lanthanum and cerium, which are also rare earth elements, are mainly produced in China, so this does not solve the problem of dominance in the upstream supply chain. But with every kilogramCompared with $100 of neodymium and $400 per kilogram of dysprosium, $5 per kilogram of lanthanum and $7 per kilogram of cerium are expected to reduce the price of new energy vehicles by a large margin.

Figure 1 Compared with the evenly distributed neodymium in traditional NdFeB magnets, Toyota's magnets only place neodymium on the surface of the magnet.

In order to reduce the content of neodymium, Toyota has taken a variety of measures. Simply replacing the neodymium in the magnet with lanthanum and cerium is not realistic, because it will produce an inferior magnet with low coercivity and heat resistance, which means that the performance of the motor cannot be guaranteed. Therefore, Toyota's new magnet fixes all the lanthanum and cerium particles in the core, and then coats the core with a layer of neodymium. In addition, Toyota has reduced the size of all metal particles.According to research, reducing the size of rare earth magnet components can effectively improve the magnetic energy stored in the magnet. The Toyota researchers successfully reduced the components of this magnet to the traditional magnet.1/10。

Without any loss of performance and coercivity, the neodymium content of this Toyota magnet is only that of traditional NdFeB magnets.20-50%. But for electric cars,For the time being, they have not been able to achieve the same level of energy efficiency improvement, which can only bring about20% increase. However, this is enough to reduce the cost of the motor.

At present, this magnet technology is still in its infancy, and more research is needed before it can be used in cars. Toyota hopes that this magnet will be used inIt began to be used in the power steering system of automobiles in the early 2020 s, and gradually spread to electric vehicle motors in the later period.

As a leader in hybrid vehicles, Toyota is hesitant to fully enter the all-electric vehicle market. However, this does not mean that Toyota researchers will ignore electric vehicle technology. Last summer, Toyota said that a solid-state battery in its research institute that is lighter, smaller and has a better operating temperature range than the batteries used by competitors such as Tesla and Chevrolet is about to enter the production process design.

Source: magnet manufacturers Youlian Magnetic Industrywww.youliancy.com


 

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