Austria: new composition magnet aims to improve electric cars

Development opportunity

Researchers at St Pölten University of Applied Sciences, Austria, working in collaboration with counterparts at Sheffield University, UK, have devised ways to optimise the composition of magnets that may make hybrid and electric cars more cost-competitive.

The research has developed simulations that make it possible to identify the optimal composition and structure of the magnets, balancing performance against the cost of the raw materials.

Hybrid and electric cars need high-capacity permanent magnets to achieve the best performance. However, in order to ensure these cars can compete on price with cars that have petrol or diesel engines, a balance has to be struck between the cost and the capacity of the magnets.  The magnetic material currently in use requires a high proportion of rare

earths, which are both expensive and in short supply. The researchers have studied how to reduce the amount of rare earths required.

The computer simulation methods are being applied to examine how the chemical composition and structure of a magnet influences its performance. This information can be used to identify ways to optimise the magnetic material so that it requires fewer expensive raw materials, yet continues to deliver the best possible performance.

Typical electric or hybrid drives contain around two kilos of magnetic material. At present, neodymium iron boron magnets form the basis of this. These have considerably less mass than conventional magnets, but deliver the same level of performance. In order to ensure the magnetic properties are retained even at high temperatures – such as those that occur within a car – the rare earth element neodymium is partially replaced by dysprosium, another rare earth element, which is in short supply and expensive.

Given that in just a few years, all new cars will be required to be fitted with a hybrid or electric drive, the cost and scarcity of dysprosium will be increasingly important.

The computer simulation reveals the internal workings of a magnet, breaking down complex structures into individual elements so that they can be evaluated. By breaking down the microstructure into millions of tetrahedrons and prisms, it is possible to recreate the spatial distribution of the metallic phases within the magnet in a computer model and then simulate the effect that changes in the proportion of dysprosium have on the coercive force of the magnet.

Magnet manufacturers have already expressed considerable interest in the project and have invited St. Pölten University of Applied Sciences to work in cooperation with them.