Aluminium, a greater substitute for rare earth elements in Electric Vehicles

The rising demand for electric vehicles (EVs) has brought to light the problem of using rare earths in contemporary technologies. Fortunately, there are many solutions for eliminating the usage of rare earths in EVs. Induction motors, for example, have widely been employed in the EV industry and utilise aluminium windings or copper on the rotor. They have a higher peak power and torque density than permanent magnet (PM) motors but a poorer efficiency.

Another possibility is a wrapped rotor motor, which uses coil windings instead of magnets on the rotor. This controls the stator and rotor fields and is used by firms such as BMW and Nissan. Regarding alternative magnetic materials, attempts are being made to create magnets that do not include rare earth and can compete with their performance.

Proterial has created high-performance ferrite magnets that only need a little increase in magnetic material to maintain power density. Niron Magnetics is developing iron nitride magnets, while the European PASSENGER project is investigating manganese aluminium carbon alloys and strontium ferrite.

Finally, optimising other aspects of the motor design may assist in mitigating the effect of utilising ferrite magnets. Ultimate Transmissions, an Australian business, has developed a ferrite motor design that combines bigger magnets and greater speeds to provide power equivalent to rare earth PM motors. The magnets in the rotor must be properly contained, which might be solved with a carbon fibre cover.

For EVs, switched reluctance motors are also being studied. While they have historically had poorer power and torque density, advances in design and control systems are helping to overcome these constraints. For example, Advanced Electric Machines has created a segmented rotor that minimises acoustic noise and torque ripple while increasing power and torque density.

As per AL Circle’s Outlook report, aluminium consumption in the automotive industry will continue to rise in the next years, as the need for lighter, more fuel-efficient, and safer cars rises. Along with conventional uses, aluminium is employed in the automobile body, gear, wheels and gearbox. To know more about how the automobile industry will function, please have a look at AL Circle's “Global Aluminium Industry Outlook 2023”.