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Fraunhofer works on the recycling of permanent magnets from electric motors

The project FUNMAG from high school Fraunhofer IWKS (specializing in resource and material recycling) aims to demonstrate the economic and technical feasibility from the recycling of magnets from large-scale electric motors. Funded by the German state through the Hessen Agentur agency, the Fraunhofer team is working to demonstrate that electric motors with recycled magnets can offer the same performance than those with new magnets.

Permanent magnets are currently essential for synchronous electric motors in electric vehicles. Embedded in their rotor, they provide a magnetic flux when they are magnetized with another field, not losing their properties once the cause that causes the magnetism ceases. Thanks to them, no external excitation or brushes are needed to generate the magnetic field in the rotor and make it rotate when exposed to the externally generated field in the stator, which makes them more compact and simpler.

After his industrial generalization in the 1990s, they have increased their demand by the automotive industry until in 2018, manufacturers opted, in 93% of cases, to equip their electric cars with permanent magnet motors. They are scarce, expensive and difficult to recycle and, today, although there are other alternatives, the two largest producers of rare earths in the world are China and the United States.

According to the Fraunhofer institute, despite how expensive they are and the difficulty involved in their production, magnets they usually end up in a junkyard at the end of their useful life, where they melt together with the rest of the steel. However, there are now proven methods for recycling these magnets. With the FUNMAG project (“Functional Magnetic Recycling for Sustainable Electric Mobility”), the team of scientists set out to bridge the gap between theory and practice.

To perform their experiments, the team acquired an electric bike, an electric scooter and a hoverboard. His intention was to analyze the characteristics of the electric motors of each of these vehicles in order to determine the real specifications and compare them with those of electric motors with recycled magnets, explains project manager Konrad Opelt.

recycling permanent magnets electric motors fraunhofer-interior
If the magnets of discarded motors are separated, the result will generally be a mixture of several magnets, the precise characteristics of which are undefined.

For the study it was essential to start from realistic cases. If magnets are removed from motors that have been discarded the result will generally be a mix of various magnets, whose precise characteristics are undefined, continues to explain Opelt. “Therefore, our goal was to show that the recycling process can also cope with undefined base materials, with these unknowns in the process. And no one has done this before us.”

With recycling, and compared to the production processes of a new magnet, some steps can be skipped. The melting of the material Starting at about 1,400 degrees is not necessary, and can be omitted for recycled magnets. It would also alleviate the harmful burden on the environment caused by the removal of raw materials for the environment.

The old magnets are put in contact with a hydrogen atmosphere and then go through the usual steps of the manufacturing process. According to Fraunhofer, in the recycling process thousands of magnets could be processed simultaneously in the recycling process. The performance of recycled magnets can be determined in the finished product or even in the previous powder stage.

Fraunhofer scientists are currently working to optimize the recycling process. Opelt is confident that the recycled magnets can soon be used in electric motors. A portfolio of properties will be derived from your research that will provide future users with recommendations on how the recycling process can be modified in such a way that the desired properties for the magnets are achieved, depending on the initial composition.

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