How an electric car works
As emissions regulations around the globe get tougher, carmakers are focusing on the next big thing: electric vehicles.
There are two main types of electric car that can use external electrical power as fuel: pure electric, such as the Tesla Model S, and plug-in hybrids like the Mitsubishi Outlander PHEV. In addition to these, there are conventional hybrid vehicles such as the Toyota Prius, which cannot be charged from external sources.
Pure electric vehicles (EVs) are essentially a battery pack, electric motor and controller electronics including an energy management system. These vehicles must be charged from an external electrical power source.
Plug-in hybrids and conventional hybrids combine an electric motor and battery pack with a petrol or diesel engine. The electric motor can be used at low speed in situations like start-stop traffic where high torque is required, while the petrol motor is used at higher speeds for increased fuel efficiency.
Unlike conventional hybrids, plug-in hybrids provide owners the option of charging from an external power source to top up the battery. Both plug-in and conventional hybrids aren’t limited in range by battery storage like pure EVs.
What drives an EV?
Motors commonly used on EVs include permanent magnet motors and induction motors.i Another type of emerging EV motor technology is the switched reluctance motor. For EVs, the efficiency of the motor plays a significant role in determining vehicle characteristics like range.ii It’s worth noting that different motor technologies also come at different costs, impacting the affordability of EVs.
For example, Honda uses square copper wire instead of round to help reduce the size of the motor in its Accord Hybrid model, while Tesla moved to a permanent-magnet motor from AC induction motors for its Model 3.
Greater efficiency and conserving power are important issues for both pure and hybrid EVs. The key will be to employ innovative techniques like regenerative braking, where the energy generated by braking is converted back into electricity, helping the battery stay charged. Despite these new features, the future of EVs is closely aligned with both battery technology and pricing.
In 2017, lithium ion battery prices were down 24 per cent on 2016 – about 20% the price in 2010.ii,iii Cost and capacity of power storage is also under the microscope through new development. US-based start-up Sila Nanotechnologies is one of many companies working to increase lithium ion battery capacity. iv Others like Imecv and Solid Power are also working to create 'solid-state batteries' – replacing the wet electrolyte with a solid, to increase energy density.vi
Smart vehicle design plays a big role in EVs. The lithium ion batteries in the Tesla Model S are not just a power source. Designers have turned the approximate 550kg of battery weight to their advantage, by mounting them low and between the front and rear wheels. The result is a low centre of gravity that aids vehicle handling.
Vehicle weight is also becoming a focus, with weight reductions in powertrain technology, as well as structural components aiding vehicle performance.vii
In 2017, 2,284 plug-in hybrid and battery EVs were purchased in Australia. That's more than double the previous year, yet still only 0.2 per cent of the 1.189 million cars sold in Australia.viii The increase in sales was complemented by over 23 EV models becoming available – a 44 per cent increase on 2016.ix,x
The Australian figures compare to around 1 million EVs sold globally in 2017.xi In the same year, more than 40 new plug-in hybrid models were released in the USA. These figures will only rise, as automotive manufacturers indicated plans to release more electric car variants, while also increasing investment in the development of more hybrid and electric models.xii
While electric cars may seem a long way away from making a dent in Australian sales of conventional petrol and diesel-powered cars, governments in other markets have made moves to change their vehicle markets significantly. Research from countries like China, Norway and certain US states has demonstrated government incentives can help aid market EV adoption through increased subsidies or reducing taxes.xiv
According to research by McKinsey, China's EV market has seen significant growth because of effective subsidies and the introduction of new EV models to the domestic market. Sales reached 650,000 units in 2016xv and nearly 400,000 new EVs were delivered to Chinese buyers in 2018 from January to June.xvi
In fact, China's growth has been so dramatic that it overtook the USA as the largest market for EVs in 2016.xiv This trajectory has been maintained, with Chinese demand driving global EV sales above the one million mark.xv
Another factor driving electric car sales globally is their affordability to run versus fossil fuel-powered combustion engines.xvii
With more models becoming available, greater efficiencies and purchase prices coming down, you’ll no doubt see more and more electric cars on Australian roads.
i Qin, N. 2016, 'Electric Vehicle Architectures', http://evsummit.org/speakers/presentations/2016/Workshop_Powertrain_Qin.pdf, viewed 3 September, 2018.
ii Adams, A. 2018, 'The secret of electric cars and their motors: It's not all about the battery, folks', TheDrive.com, http://www.thedrive.com/tech/17505/the-secrets-of-electric-cars-and-their-motors-its-not-all-about-the-battery-folks, viewed 3 September, 2018.
iii Biswas A. K and Tortajada C 2018, 'Electric vehicles are changing the world. And they're only just getting started', The Conversation, 1 March, https://theconversation.com/electric-vehicles-are-changing-the-world-and-theyre-only-just-getting-started-90402, viewed 3 September, 2018.
iv Temple, J 2018, 'This battery advance could make electric vehicles far cheaper', MIT Technology Review, April 11, https://www.technologyreview.com/s/610792/this-battery-advance-could-make-electric-vehicles-far-cheaper/, viewed September 3, 2018.
v Imec, Smart Energy, https://www.imec-int.com/en/smart-energy, viewed 3 September, 2018.
vi Imec 2018, 'Imec reaches milestone for next-gen solid-state batteries to power future long-range electrical vehicles', https://www.imec-int.com/en/articles/imec-reaches-milestone-for-next-gen-solid-state-batteries-to-power-future-long-range-electrical-vehicles, viewed September 3, 2018.
vii McKinsey 2017, 'Trends in electric vehicle design', https://www.mckinsey.com/industries/automotive-and-assembly/our-insights/trends-in-electric-vehicle-design, viewed 3 September, 2018.
viii Federal Chamber of Automotive Industries, 'Australia's new vehicle market', Sales, https://www.fcai.com.au/sales, viewed 3 September, 2018.
ix ClimateWorks Australia and the Electric Vehicle Council 2018, The State of Electric Vehicles in Australia - Second Report: Driving momentum in electric mobility, June 2018, http://electricvehiclecouncil.com.au/wp-content/uploads/2018/03/The-state-of-electric-vehicles-in-Australia-2018_compressed.pdf#page=3, viewed 30 August, 2018.
x ClimateWorks Australia and the Electric Vehicle Council 2018, The State of Electric Vehicles in Australia - Second Report: Driving momentum in electric mobility, June 2018, http://electricvehiclecouncil.com.au/wp-content/uploads/2018/03/The-state-of-electric-vehicles-in-Australia-2018_compressed.pdf#page=10, viewed 3 September, 2018.
xi ClimateWorks Australia and the Electric Vehicle Council 2018, The State of Electric Vehicles in Australia - Second Report: Driving momentum in electric mobility, June 2018, http://electricvehiclecouncil.com.au/wp-content/uploads/2018/03/The-state-of-electric-vehicles-in-Australia-2018_compressed.pdf#page=6, viewed 3 September, 2018.
xii Quain, J. R 2017, '2017 could prove to be a turning point for plug-in hybrids', The New York Times, May 4, https://www.nytimes.com/2017/05/04/automobiles/wheels/plug-in-electric-hybrid-automobiles.html, viewed 3 September, 2018.
xiv Jolly, D., 2015, 'Norway is a model for encouraging electric car sales,' The New York Times, October 16, 2015, viewed 15 December 2015, http://www.nytimes.com/2015/10/17/business/international/norway-is-global-model-for-encouraging-sales-of-electric-cars.html?_r=0
xv Hertzke P, Muller N and Schenk S 2017, 'Dynamics in the global electric-vehicle market', McKinsey, July 2017, https://www.mckinsey.com/industries/automotive-and-assembly/our-insights/dynamics-in-the-global-electric-vehicle-market, viewed 3 September, 2018.
xvi EVvolumes.com, 'China plug-in vehicle sales for the 1st half of 2018', http://www.ev-volumes.com/, viewed 3 September, 2018.
xvii The Economist, 2017, 'The death of the internal combustion engine', The Economist, 12 August, https://www.economist.com/leaders/2017/08/12/the-death-of-the-internal-combustion-engine, viewed 3 September, 2018.