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From minus to plus – new magnet technology enhances green power

There are magnets in virtually all modern electrical equipment. However, the current versions are often based on metals with heavy impacts on the environment. Associate Professor Mogens Christensen is researching a new and cleaner magnet technology; research which also opens up for new opportunities to exploit and store electricity. Find out more in the podcast (in Danish) below.

2020.02.06 | Dorthe Lundh

Two men are standing by a crate full of magnets on a factory floor.

Mogens Christensen (left) is conducting research to develop more efficient and sustainable magnets. Among those he is working with is Peter Kjeldsteen (right), head of development at the company Sintex. The black rings in the picture are magnets for electric motors. Photo: Dorthe Lundh

Electromagnetism was discovered by H.C. Ørsted in 1820, and it is a vital element in refrigerators, phones and all the other appliances that make modern life so convenient.

Even though magnet technology has evolved over the past 50 years to such an extent that electric versions of everything from toothbrushes to cars are now commonplace, there is a number of drawbacks in the current technology. Not least with regard to the green transition.

Mogens Christensen, associate professor at the Department of Chemistry at Aarhus University, is therefore focusing his research on developing a new magnet technology. "One of the challenges in many of the magnets we use today is the material they are made of. Powerful magnets in electric cars and a wide range of other applications are based on neodymium. However, this element is a rare earth metal, and mining it has serious impacts on the environment. Moreover, China has a virtual monopoly on the market, making trade in the metal vulnerable. Therefore, our technology is based on more sustainable elements such as iron and strontium.”

The prospect of being independent of Chinese metal suppliers alone will generate global demand for the new magnet technology, Mogens Christensen predicts.

When the lab meets the factory

However, there are a lot of nuts to crack on the way. Weight and mass are two of them. Because if the new magnets are to become a technological step forward, they cannot take up more space or weigh more than current magnets, and they must be just as powerful. This is a challenge.

"Much of our work in the lab is about getting the crystals in our materials to face in the same direction, in order to achieve the desired magnetic output. This is not entirely trivial," says the associate professor.

In order to test the properties of the material, the chemical research group is dependent on good partners from industry. The company Sintex is one of them. The company is in the Grundfos group, and its factory produces magnets used in pumps all over the world.

Sintex is contributing to the research project by pressing and testing materials from the university laboratory.

"When Mogens Christensen and his group have a material in powder form that they consider is interesting to go forward with, we press the material into discs on our machines," says Peter Kjeldsteen, head of development at Sintex.

During this phase, it is often clear that the laboratory and the factory are working at different scales. Chemists at the university consider one gram of material as a relatively large amount, while at the factory a kilo is not considered as very much at all. Therefore, both partners have to be creative to manufacture prototypes of the new magnets. So far, they have succeeded.

Peter Kjeldsteen has high expectations of the new magnet technology.

"At Sintex, we’re particularly interested in filling a gap we see in the market. Today, expensive and powerful, high-end neodymium magnets and cheap, low-end ferrite magnets demand more material to achieve the desired output. If we can offer an intermediate product, we’ll have access to an enormous market for a wide range of products,” forecasts the head of development.

Magnets reduce electricity losses

According to Mogens Christensen, the new magnet technology is not only capable of optimising or minimizing today’s electric motors. It may also be possible to replace batteries and the way in which we store energy.

"We’re working on improving what is known as flywheel technology. This converts electricity into kinetic energy by having an electric motor spin a flywheel up to 30-50,000 revolutions per minute, a bit like when a potter spins his wheel. When you need to use electricity, the flywheel drives a dynamo that sends the electricity out to the grid. One of the advantages of the technology is that there is no friction, and this reduces the electricity loss. Another advantage is that the flywheel can be discharged quickly," explains Mogens Christensen, and continues,

"For example, you could charge an electric car in just a few minutes using flywheel technology. Today, however, car batteries don’t have the capacity to be charged so rapidly."

The researcher predicts that, with upgraded flywheel technology, it will be possible to exploit electricity from green energy sources better than we do today.

"At the moment, we're not using electricity from wind turbines and solar cells optimally. There are large losses if we want to store the electricity for use it on days when there is no wind or sun. We’re working on reducing these losses with flywheels based on the new magnet technology," he says.

Implementation is just around the corner according to Mogens Christensen.

"My guess is that in four to five years, solar panels, for example, will be able to store electricity using flywheels based on our magnet technology. Initially, there will be some very specific applications, but with a sufficiently high level of investment, development and deployment could quickly take off."


Contact

Assosciate Professor Mogensen Christensen,
Department of Chemistry
Aarhus University

Mail: mch@chem.au.dk
Mobile:  +45 6177 7451

Faculty of Natural Sciences