New developments in electric train technology, such as higher-voltage systems and greener motors, will increase the success and wider adoption of battery electric vehicles.
Battery electric vehicles have made a lot of progress in Europe, as consumers opt for cleaner technology and lawmakers strengthen emissions rules for automakers in a bid to reduce pollution levels. Electric vehicles have already improved the environment by helping to cut CO2 and particulate pollution. But the latest developments in electric train technology are helping to take that innovation one step further.
Making motors smaller and encapsulating them in modular systems with other key components could not only be the next step to cutting the costs of electric motoring, but it will help make it even greener.
The European Union’s target this year aims to reduce average fleet emissions of new cars sold in the bloc to 95 grams per kilometre. Automakers that fail to hit this target will face fines of €95 for every excess gram of CO2 they emit. Juergen Pieper, an auto analyst and director of research at Bankhaus Metzler in Frankfurt, explains: “The incentive is rather big. The reaction of most automakers – complaining and at the same time saying ‘yes, we will do more’ – speaks for itself.”
High-voltage battery technology
The emissions targets are one of the reasons Pieper believes the shift towards an electric future is now fully underway, despite the fact that technology needed for the next generation of battery electric vehicles is still in its infancy, technology such as higher-voltage electrical systems.
While most manufacturers have traditionally used 400-volt layouts, automakers such as Porsche and Hyundai have started to introduce larger 800-volt units with big environmental benefits.
Professor Damijan Miljavec of the University of Ljubljana’s Faculty of Electrical Engineering was instrumental in developing a high-voltage unit for the European Union research project Drivemode, which is seeking to develop compact modular electric train technology, including power electronics, gearboxes, and motors. These modules are designed to be scalable according to the power requirements of different vehicle segments.
Professor Miljavec’s initial task was to choose a smaller, greener motor for the module as he explains: “We increased the speed [of the motor] by a factor of two, from 10,000 [revs per minute] to 20,000, which means, to maintain the same power output, we can halve the size of the motor, which reduces the amount of copper and the amount of magnets.”
This is significant because permanent magnet motors use rare-earth materials that are unsustainably mined. The ores that rare earths are extracted from are often separated using large amounts of toxic compounds such as sulphate, ammonia, and hydrochloric acid. Processing one tonne of rare earths can result in many more tonnes of toxic waste.
Benefits of Drivemode’s motors
In addition to halving the use of these materials in their motors, Drivemode also claims the modules are fully recyclable.
Miljavec explains: “You can take out the copper and reuse the parts by melting them down and producing new parts. You can also quite easily remove the magnets and reuse them, so it is 100% recyclable.”
From a practical view, these smaller, lighter motors also offer energy savings for consumers. Reducing the weight of the vehicle means it can travel further on a single charge. This leads to an increased vehicle efficiency of about 3% or 10 miles (16 km) more range for an average battery electric vehicle. The silicon carbide inverter used by the EU project also reduces power leakage between the battery and the motor by up to 2%.