Besides batteries, electric powertrains or motors are the most central component of an electric vehicle, with the two components accounting for roughly 50% of its total manufacturing cost (15% of which come from the motor) [6]
How electrical motors work
Electrical motors were invented in the 19th century and fundamentally work differently than combustion motors. Instead of generating energy from fuel combustion, they use electrical energy to create a magnetic field which generates rotational motion [1]. Furthermore, electric motors typically do not have gears. This is because they are built in a way that enables them to reach high torque quicker than combustion engines [4]. Their construction is also less complex than combustion engines, as they consist of fewer individual parts [2].
This construction of electrical motors makes them more efficient, as there is less energy lost to heat and friction. In practical use, an electric motor has an efficiency of about 64%, compared to roughly 20% efficiency for combustion engines. They also have a significantly higher efficiency than hydrogen motors (27%), if the energy loss during production of hydrogen is taken into account [3]. Electric motors can also generally accelerate quicker than combustion engines [4]. Because they are built with less parts, they are also generally less prone to failure and easier to maintain [2]. Electrical motors are also lighter than combustion motors. For instance, a modern electric motor produces up to 20kW per kilogram, compared to roughly 5kW per kilogram for a typical combustion engine. This means that a 300 horsepower electric motor can weigh as little as 20 kilograms [7] [8]. However, in real world use electric cars are not lighter than conventional ones, as the lighter motor is offset by the high weight of batteries and their supporting frame [5].
[1] Joachim Herz Stiftung. (2021). Grundwissen: Elektromotor. https://www.leifiphysik.de/elektrizitaetslehre/kraft-auf-stromleiter-e-motor/grundwissen/elektromotor
[2] Frankfurter Allgemeine Zeitung. (2019, November 4). So funktioniert ein Elektroauto [Video]. YouTube. https://www.youtube.com/watch?v=Zv1or8Hjv2U
[3] Bundesministerium für Umwelt, Naturschutz und nukleare Sicherheit. (2021). Effizienz und Kosten: Lohnt sich Der Betrieb eines Elektroautos?. https://www.bmu.de/themen/luft-laerm-mobilitaet/verkehr/elektromobilitaet/effizienz-und-kosten
[4] Rudschies, W. (2020, December 17). Elektroantrieb: So funktioniert ein Elektroauto. ADAC. https://www.adac.de/verkehr/tanken-kraftstoff-antrieb/alternative-antriebe/elektroantrieb/
[5] Shaffer, B., Auffhammer, M., & Samaras, C. (2021, October 12). Make electric vehicles lighter to maximize climate and safety benefits. Nature. https://www.nature.com/articles/d41586-021-02760-8
[6] Carlier, M. (2021, July 21). Typical manufacturing costs of a battery electric vehicle as of 2018. Statista. https://www.statista.com/statistics/940722/bev-manufacturing-cost-by-type
[7] Hommen, M. (2020, March 5). Neue E-Motoren Generation: Nur zehn Kilo schwer und so leistungsfähig wie ein Porsche-Boxermotor. Handelsblatt. https://www.handelsblatt.com/mobilitaet/motor/neue-e-motoren-generation-nur-zehn-kilo-schwer-und-so-leistungsfaehig-wie-ein-porsche-boxermotor/25613336.html
