Magnetic materials for electric mobility and vehicles
Abstract
The proposed research project deals with magnetic materials in dynamic environments for
applications in the electro mobility and vehicles sector. In order to facilitate an efficient
transition from combustion vehicles to electric vehicles, research in many different areas is
needed, from improved energy storage (batteries) to electric machines and power electronics
as well as sustainability, manufacturing and recycling.
At Högskolan Väst (HV), we are rapidly expanding research and education of all aspects of
electric mobility and vehicles solutions, with several industrial partners such as Polestar and
T-Engineering involved. Although an electric vehicle and its drivetrain is fundamentally more
energy-efficient than combustion vehicles, increasing efficiency even further without too
much negative consequences are of great importance since the battery is the most
expensive and heavy component of an electric vehicles.
The heart of an electric vehicles is the electric machine that propels the vehicle as
well as recuperate some of the energy under retardation. Development of electric machines
for vehicles has converged to permanent magnet synchronous machines (PMSM) due to its
highest efficiency as known today. The key component in such a machine is the permanent
magnet that ideally should have a large magnetic moment and large anisotropy that gives a
high energy product. At the same time, it should ideally be cheap and environmentally
“clean”. The best performing magnets used today are rare-earth based materials. However,
there are great geopolitically, sustainability and environmentally concerns over such
materials and development of alternative magnets without rare earths that have similar
performance is the heart of the proposed research.
In an electric machine, the magnet is subjected to a harsh environment with strong
fluctuating thermal, electric, and magnetic fields as well as mechanically challenging
conditions. All these magnetization dynamics processes will be studied in detail using
theoretical modelling using large-scale computations with a combination of first-principles
calculations and atomistic spin dynamics simulations within the UppASD software package.
The developed theoretical framework is accurate but still fast enough to reach device length
scales using massive fine-grained MPI parallelization and has a well proven track record.
Contrary to most other modelling efforts, we employ material specific studies that can give
not only qualitative results but also quantitative results that can be compared and tested
against experimental methods. Recent developments in the software are inclusion of
longitudinal fluctuations of the magnetic moments that yield even more accurate
description of the magnetic properties at finite temperature, an implementation of a new
computational framework for combined spin and molecular dynamics where the magnon
and phonon properties are coupled together. These calculations will allow for novel studies
where spin and thermal transport are treated on an equal footing. In addition, recently we
implemented Wang-Landau sampling that in combination with quantum Bose-Einstein spin
statistics provides accurate magnetic thermodynamic properties such as specific heat, spin
entropy and magnetic free energy, relevant to use as input to further thermodynamic
modelling using CALPHAD methods.
