DOE invents high-efficiency magnet for EV and hybrid motors

The DOE’s Argonne National Laboratory has invented a new magnet technology, called HyMag, which could lead to greater efficiency and lighter weight in EV and hybrid motors.

HyMag increases a permanent magnet’s usable magnetic flux density, a property of permanent magnets that can be harnessed for power generation.  “The higher the flux density you use for power generation, the more energy you generate,” said Argonne Group Leader Kaizhong Gao.  “You have to have higher flux density in order to have more efficiency.”

In the 1990s, conventional permanent magnets composed of neodymium, iron and boron became widespread, yet they resisted efforts to improve performance, said Zhang.

“In the past 15 to 20 years, the increase in magnet energy products reached a plateau due to lack of material solutions,” said Zhang. Researchers have looked into various ways to improve the composition, microstructures, and processes of existing magnetic materials. Each could lead to a small improvement of the magnet’s energy product. However, the magnetic flux of a magnet decays rapidly with distance, which makes the use of magnetic flux insufficient.

Gao and fellow Argonne inventor Yuepeng Zhang have improved permanent magnet performance by combining hybrid layers of material in a way that reduces the flux leakage.

When designed properly, the gain in the magnet’s usable flux density ranges from 10 to 30 percent, depending on the application and working temperatures, said Gao and Zhang.

HyMag could especially benefit weight-sensitive applications because the technology’s higher efficiency could lead to downsized structures.

On top of the greater efficiency and weight shedding, in certain applications, HyMag technology may require up to 90 percent less (by weight) rare-earth elements, such as dysprosium and gadolinium, than regular magnets with similar performance.

These elements, mostly imported from China, can be scarce, expensive and difficult to recycle. According to Gao and Zhang, a typical vehicle traction motor contains approximately a tenth of a kilogram of dysprosium.


Source: Argonne National Laboratory

  • earl colby pottinger

    Sounds like they have duplicated Tesla work of using a Halbach array to increase the magnetic flux in the motor.

    • dogphlap dogphlap

      Just what I was thinking. Though to be honest I’m just a guy looking on with my face pressed against the window so what I conjecture may not be the case. After all Tesla did not invent the Halbach array, they just adopted it to great affect in the Model 3 rear motor.

      • earl colby pottinger

        I realize that, It just seems that Tesla spends money taking things that have been known before and applying them in ways other car companies never bothered with to get better performance than their competitors.

  • Damned_Right

    Please, be careful not to allow our current U.S. Energy Secretary to know about this – or his boss..

  • Mark B

    This is nonsense. I have never seen the term “magnet efficiency” before. How do you calculate it?

    • earl colby pottinger
      • Mark B

        I’ve been designing magnets since the early 70’s – that article does not contain the word “efficiency”. How many have you designed?

        • earl colby pottinger

          Then read. I work in computers, the number of times I have to correct people with decades more experience than me I have lost count.

          It does not matter how many years you have been doing something if you have always been doing it the same old way.

          In other words, in all those years have to been making better motors than Tesla? If so, why have you not sold your designs to them?

          • Mark B

            I’m sorry – but I work in computers and recently designed the most efficient, energy wise, video server that is used World wide.

            I am currently working on a hybrid drive train – I don’t sell designs – I make products with them. I just designed a 3 phase rectifier that is 97% efficient and component cost is just $5 for 60Amps.

          • A K

            I would love to learn more about your hybrid drive train. We have just built a 400V 950Nm induction motor for a KERS project. regards. AK

          • Mark B

            Sorry – but that’s proprietary until it is released. Evaluating hundreds of motors and generators and rectification methods is a lot of work.