IDTechEx writes:
Firstly consider electrification. Both conventional and electric vehicles, whether for land, water or airborne use, are rapidly becoming more electrical and electronic and less mechanical. For example, the newly popular switched reluctance traction motors have no magnets or windings in the rotor. Indeed, the material cost is halved, but control and getting the optimal torque curves is more challenging, calling for double the electronics.
A different trend for traction motors for both hybrid and pure electric vehicles is for there to be more than one per vehicle. For example, in-wheel motors as on the best-selling pure electric bus the BYD B9 recently landing orders up to 2000 at a time. Many cars planned for imminent launch have in-wheel motors in two or four wheels but doubling of motors is most popularly for other reasons such as four wheel drive, greater efficiency, release of space, modularisation and redundancy all achieved with inboard motors. The unique IDTechEx report, "Electric Motors for Electric Vehicles 2015-2025" analyses all this and give forecasts for the place of electric traction motors in the creation of the $500 billion plus market for electric vehicles emerging in 2025.
Secondly comes the megatrend of integration, of which those in-wheel motors are a part, as they increasingly integrate power electronics, brakes and much more besides. However, there is much more to it than this. Mechanical, electric and electronic components are merging. Several companies are printing electric cars and Harvard University has printed much of the electronics, a lithium battery and it plans to print a motor - though all of these are small initially. Meanwhile, Toyota hybrid transmissions include two motors, one acting as both generator and torque assist and the power electronics is embedded.
Structural electronics is the end game for much of this as the batteries become solid state and are part of the internal and external bodywork to save space, self-cool and possibly manage higher currents to drive those motors. See the IDTechEx report, "Structural Electronics 2015-2025".
Structural supercapacitors have been demonstrated in car bodywork and there is some argument that traction motors should be driven by supercabatteries (hybrid supercapacitors sometimes in the form of Asynchronous Electrochemical Double Layer Capacitors AEDLC - also called lithium-ion capacitors). These can have the superb one million cycle life of the supercapacitor, exceptional power density, good series resistance and the energy density of the lithium-ion battery or at least a lead-acid battery. Use in hybrids is now commonplace for supercapacitors, so who knows. Higher power densities may call for motors improved so they can withstand the newly available pulses of power thus delivering better performance.
In aircraft, on the other hand, extremely lightweight is about to be achieved with structural photovoltaics, structural batteries and new traction motors with exceptional power-to-weight ratio. For a 200 year old technology, the electric motor is now changing surprisingly rapidly.
Zero pollution at point of use is another megatrend and it is achieved with pure electric powertrains (battery, supercapacitor, supercabattery) or fuel cell hybrid powertrains, currently only commercially successful in thousands in forklift trucks in the USA.
Innovations starting in forklift trucks are not new. Asynchronous motors were successful there first and are now commonplace in cars, buses and so on. However, what is usually forgotten is the fact that energy harvesting is also zero pollution at point of use and it is becoming capable of providing very serious amounts of energy such as kilowatts, albeit intermittently. However, remember that the power demands of a vehicle are also intermittent. Indeed, intermittency is greatly reduced by multi-mode energy harvesting such as harvesting movement in all directions plus heat difference, light, infrared and so on. It means that battery expensive, short-lived traction battery can be smaller in future as these technologies become commercial to drive the rapidly changing traction motors in vehicles.
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