Designs on electric hybrid cars: the benefits of AMCs
01 September 2020
Richard Thompson, Commercial Director of aluminium matrix manufacturer, Alvant, discusses how a new breed of materials could unlock significant improvements in power density and transient response for electric and hybrid vehicles.
Aluminium matrix composites (AMCs) first appeared in automotive applications in the 80s, but as carbon composites became more widely adopted, they were soon forgotten. However, almost four decades later, subsequent R&D investment into their manufacturing has resulted in significant progress. AMCs are now firmly back in the game.
Made from aluminium alloy mixed with particles or long or short fibres, they are an exciting option for designers and engineers looking for the seemingly impossible: lightness, stiffness and strength. Compared to unreinforced metals, AMCs can also have superior wear resistance, lower coefficients of thermal expansion and superior electrical conductivity.
Customisable, AMCs can be stronger than steel and less than half the weight, as well as up to 50 percent stiffer and almost 300 percent stronger than carbon fibre.
A solution tailor-made for EVs
AMCs radically improve the efficiency and responsiveness of the electric rotors used in electric and hybrid vehicle motors. In conjunction with UK motor manufacturer, Yasa, engineers at Alvant developed a rotor that is 40 percent lighter than the original. It also had an increased power-to-weight ratio, made possible by the stiffness of AMCs, which can reduce the air gap between the rotor and stator in axial flux motors.
The improvement in strength and stiffness means the rotor speed can be increased which, in turn, increases power density by a massive 225 to 300 percent. Now things get interesting! If the rotors in axial flux motors (AFMs) that are suitable for passenger cars were made from AMCs (rather than steel), mass and inertia would be reduced by 45 to 73 percent and, overall, motor weight would be reduced by 19 to 25kg. These gains could have a worthwhile impact on performance and range.
Read the full article in the September issue of DPA.
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