BASIC KNOWLEDGE - ELECTRIC VEHICLES Electromobility - Electric vehicle basics, how they work, and how they’re powered
Electric Vehicles (EVs) are the future of motoring. But what types of EVs exist? How do they work and how can they be charged? What are the developments in the electric car market and how much do they cost? Learn this and more in the following article.
In recent years, governments all across Europe and the rest of the world have made pledges to support the manufacture and proliferation of ultra-low-emission vehicles, while several major car brands have either already built electric cars or have plans to do so. Some vehicle manufacturers, such as British carmaker Bentley, have promised that all their products will be plug-based in the near future.
Despite electric vehicles, electric cars in particular, only having taken off and become part of the mainstream in recent years, their history stretches back farther than you may think. The very first electric car was built in the 1830s in Aberdeen, Scotland, and the technology was so successful that electric taxis took to the streets of London towards the end of the century. Due to the falling price of oil, however, their popularity didn’t last, and fossil fuel-powered cars quickly dominated.
As it has become much cheaper to produce more reliable electric vehicles that are accessible to the general public, in addition to climate concerns and their very low running costs, electric vehicles are becoming more widely produced and popular. In the next decade, we’re going to see a huge increase in the number of electric cars on our road - as well as other electric vehicles taking to the rails, skies, and seas—as petrol and diesel-powered vehicles are slowly phased out of production and, in some cases, banned from sale.
What are electric vehicles?
When we think of electric vehicles, we mostly think of any car (either hybrids or all-electric cars) that use electricity to run instead of petrol or diesel fossil fuels. While this is pretty much along the right lines, the term ‘electric vehicle’ or ‘EV’ covers any vehicle that operates on an electric motor or traction motor instead of an Internal Combustion Engine (ICE). This includes not only cars but electric trucks, planes, trains, boats and two- and three-wheelers.
In this article, we’re going to use the term ‘electric vehicle’ or ‘EV’ to refer to electric cars. As there are currently an estimated 1.4 billion cars on the road worldwide (compared to roughly 200 million motorcycles), the car is widely considered to be the most common and popular type of vehicle in use today. An electric vehicle can therefore be defined as any vehicle that uses one or more electric or traction motors for propulsion.
How do electric vehicles work?
While the specifics of how an electric vehicle operates depends on what type of EV it is (i.e., whether it’s a hybrid, battery-electric, or fuel cell electric - more on this shortly) they all broadly work in the same manner. All EVs are powered by an electric motor. This gets its power from a stack of batteries, and in most cases electric cars must be plugged in to recharge these batteries. In earlier iterations of the EV, these batteries were of the lead-acid variety but nowadays, most electric cars will use lithium-ion batteries as they’re far superior and can store a lot more energy.
In EVs - electric cars especially - the batteries are usually found positioned low down in the car. In the Tesla, for example, the battery runs along the floor. Due to the weight of the batteries (the average electric car weighs more than the average fuel-powered car!), this helps to regulate the car’s centre of gravity. Electric cars will also usually feature an auxiliary battery that is used to power the car’s electrics, much like the battery found in a conventional fuel-powered vehicle. This allows the car’s lights, infotainment system, and other functions to work even if the main battery runs flat.
The electric motor draws power from the battery to drive the car’s wheels and enable propulsion. Two motors can be used - one on each of the car’s two axles - to provide four-wheel drive. Today, all electric motors are fundamentally AC. They spin when the rotor chasing an alternating magnetic field is induced by an alternating electrical current. Older electric motors were ‘DC brushed’ which used mechanical brushes to create an alternating current. These had a high failure rate making them unsuitable for commercial electric cars.
Different types of electric vehicle
There are three main types of electric car, classed by how much electricity is used as their energy source. These are Battery Electric Vehicles (BEVs), Plug-in Hybrid Electric Vehicles (PHEVs), and Hybrid Electric Vehicles (HEVs). In addition to these three ‘main’ types of EV, there are ‘outliers’ such as range extender or fuel cell vehicles.
Battery Electric Vehicles (BEVs)
Battery electric vehicles - often referred to as ‘fully-electric’ or ‘all-electric’ vehicles - are vehicles fitted with a rechargeable battery as the sole power source. These vehicles have no gasoline engine at all. BEVs store electricity onboard with high-capacity (usually lithium-ion) battery packs. Their battery power is then used to run the electric motor and onboard electronics. Due to the absence of an ICE, BEVs do not emit any harmful emissions at all. BEVs are charged by electricity from an external power source, with their chargers classified according to the speed at which they recharge a battery (see the below section on EV charging for more information).
Examples of BEVs include the Tesla Model 3, BMW i3, Volkswagen e-Golf, and the Hyundai Ioniq.
Plug-in Hybrid Electric Vehicles (PHEV)
The plug-in-hybrid electric vehicle combines a battery and electric motor with an economical petrol or diesel engine. As can be deduced from the name, PHEVs can be recharged by plugging into an external electricity source. In addition, PHEVs can also be powered by their onboard engines and generators, and they’re able to substitute electricity from the grid for gasoline. In a PHEV, the onboard battery will usually be much smaller and have a lower capacity than those found in all-electric cars. This means that PHEVs can’t drive very far on electricity alone, requiring the combustion engine to eventually kick in.
Examples of PHEVs include the BMW i8, Toyota Prius, Ford C-Max Energi, and the Mini Cooper SE Countryman.
Hybrid Electric Vehicles (HEVs)
Hybrid electric vehicles are powered by both fossil fuels and electricity. In a HEV, electricity is generated by the car’s braking system and this used to recharge the battery. This is known as ‘regenerative braking’, a process whereby the electric motor helps to slow and bring the vehicle used to a stop using some of the energy normally converted to heat by the brakes. HEVs start off their journeys using the electric motor, then the ICE engine steps in as load or speed rises. HEVs are very similar to PHEVs except that they can’t be plugged in; electricity can only be generated via regenerative braking.
Examples of HEVs include the Toyota Prius Hybrid, the Honda Civic Hybrid, and the Toyota Camry Hybrid.
Some electric cars get their electricity from a hydrogen fuel cell instead of a battery. As such, these vehicles are referred to as ‘fuel cell vehicles.’ While there are many different types of hydrogen fuel cell at the moment, most of them have the same working principle: they combine hydrogen and oxygen to produce electricity (to propel the vehicle) and water (by-product). As hydrogen fuel cell cars are powered by this chemical process, they do not need to be recharged and can be driven so long as they are fuelled by a supply of hydrogen. Filling up the car can take less than five minutes, with the average range of hydrogen fuel cell cars sitting around 300-350 miles.
Two examples of hydrogen fuel cell vehicles are the Toyota Mirai and the Hyundai Nexo.
What is the difference between a mild hybrid and a full hybrid?
All types of hybrid cars are powered by a combination of an ICE and an electric motor. Whether a car is a mild hybrid or full hybrid depends on whether the electric motor can support the car on its own.
In a mild hybrid, the car only uses the electric motor to support the engine during acceleration and cruising. The electric motor is unable to power the car on its own. In a full hybrid, however, the electric motor can power the car on its own; the ICE only kicks in when more power is needed or when higher speeds are reached.
Powering electric vehicles (charging EVs)
The two main types of electric vehicle - the all-electric BEV and the PHEV - are powered by plugging the vehicle into a source of electricity. There’s a lot more to it than this, though, with different considerations like charging rates and speeds, voltages, ranges, and battery size.
How do you charge an EV?
An electric vehicle can be charged by either plugging it into a socket or a charging unit. Charging units are being found in more and more public places as the popularity of EVs grows, and you’re usually never too far from your nearest one. Common locations for charging points include car parks and fuel stations.
How long does charging an electric car take?
There are three main types of EV charging—rapid, fast, and slow. These correspond to power output in kW and, therefore, the amount of time it takes to charge the EV. Each charger type has an associated set of connectors that are designed for low- or high-power use, and for either AC or DC charging.
- Rapid: Rapid chargers are the quickest way to charge an EV. They’re usually found on the motorway network, in service stations, or close to main routes. They supply a high-power alternating or direct current. The average EV takes roughly an hour on a standard 50 kW rapid charging point, however, some models of EV can recharge to 80 percent in as little as 20 minutes. All rapid devices have charging cables tethered to the unit, and rapid charging can only be used on vehicles with rapid-charging capability. A good example of rapid charging is Tesla’s Supercharger network which provides rapid DC charging to drivers of its cars. These can charge up to 150 kW.
- Fast: Fast chargers are usually rated at either 7 kW or 22 kW (single- or three-phase 32A). Most fast chargers provide AC charging but there are some networks that make use of 25 kW DC chargers. Charging time varies depending on unit speed, but a 7 kW charger is capable of recharging a compatible EV with a 40 kWh battery in around four-to-six hours, and a 22 kW charger in one-to-two hours. Fast chargers are typically found at supermarket car parks, leisure centers, or other destinations where you’re likely to be parked up for a longer period of time.
- Slow: Most slow chargers are rated up to 3 kW. In reality, however, slow charging takes place between 2.3 kW and 6 kW. The most common slow chargers are rated at 3.6 kW (16A). Charging times vary depending on the type of charging unit and the EV that’s being charged. Generally speaking, a full charge on a 3 kW unit will take anywhere between 6 and 12 hours. Most slow charging units are untethered, unlike rapid and fast chargers, which means that a cable is needed to connect the EV with a charge point, such as a standard outlet plug. Slow charging is a common method of charging used in home-based settings. However, it’s not uncommon to see slow EV charging stations deployed at areas where car parks may be left for a longer period of time, such as 24-hour public car parks and workplaces. Due to the long charging times, slow chargers aren’t commonly found in other public settings.
How expensive is it to run an electric car?
The cost to charge an electric car varies depending on the type of vehicle, battery size, the type of charging system, and where a vehicle is being charged. In the UK, for example, charging an electric car at home costs roughly £8.40.
While there is no definitive answer to this question, we do know that charging an electric car is considerably cheaper than the cost of filling up a petrol or diesel engine, and can be made even more cost-effective still when tax breaks, incentives, and home-based renewable energy generation are factored in.
The electric vehicle market and the future of electric cars
The sales of BEVs and PHEVs exceeded the two-million mark for the first time in 2019. The latest electric vehicle market predictions are strong, too. Deloitte’s global EV forecast is a compound annual growth rate of 29 percent achieved over the next 10 years into 2030, with total EV sales growing from 2.5 million in 2020 to 11.2 million in 2025, then reaching 31.1 million by 2030.
By this time, EVs are expected to make up roughly 32 percent of the total market share for new car sales as per the above graph. What’s more, the market hasn’t been impacted by COVID-19 insofar as others have; the pace of recovery for the EV market will be high, with EVs having a positive trajectory during the COVID-19 recovery period.
This growth is being driven by factors including changing consumer demand and priorities, government-backed incentives and tax breaks, original equipment manufacturer (OEM) vehicle strategy, and the role that corporations are playing in supporting the transition to EVs. And as more governments set carbon neutral target years, battery technology improves, and more manufacturers start to prioritize the production of EVs - in many cases switching entirely to BEV and PHEV production - we may well see growth figures that go beyond the above predictions. Although anything could happen over the next decade, one thing seems clear: the future of motoring is electric cars.