EV 101: How Do Electric Cars Work?
By John Bogna & Emily Dreibelbis
Eyeing a more environmentally friendly alternative to your gas-powered car? Electric vehicles are growing in popularity; here’s how they get you from point A to B.
With their smooth handling and fast acceleration, electric vehicles (EVs) are an appealing way to avoid high gas prices or mitigate the environmental impact of gas-powered vehicles. Their upfront cost might be higher than gas cars on average, but there are several models under $40,000, federal tax credits to soften the blow, and a steadily improving charging infrastructure to help quell range anxiety. But how do they actually work?
The Basics of Electric Cars
Unlike a typical internal combustion engine (ICE) vehicle that runs on gas, EVs don’t require explosive combustion via burned fuel to generate the energy needed to move. Instead, they use electrical energy stored in their battery packs to turn the electric motor (or motors) connected to the wheels and drive the car forward. As such, EVs have fewer moving parts than a gas vehicle and generally require less maintenance (no oil changes).
There are several different types of vehicles that could qualify as EVs, from plug-in hybrids to fully battery-powered vehicles, and even hydrogen fuel cell-powered cars. While hybrids use a small amount of electricity, they are still generally considered gas-powered vehicles, though more efficient ones. We’ll focus specifically on how all-electric vehicles work here.
The Science Behind the Battery
Every EV has a battery pack made up of groups of lithium-ion batteries, or cells, that supply the power needed for everything from moving the car to running the air conditioning. It’s usually located at the bottom of the vehicle between the wheels.
An electric car’s battery charges in much the same way the lithium-ion battery in your cell phone does, just on a much larger scale. You connect it to the grid via an outlet or charging station, and it draws energy until it’s charged. How much energy an EV’s battery can hold will depend on its capacity, measured in kilowatt-hours (kWh). The higher the number, the higher the capacity, and the farther you can drive that EV on a single charge.
Battery sizes differ for each EV, and many models also offer multiple size options (the bigger the battery, the more expensive the car). For example, the upcoming 2024 Hyundai Kona Electric comes with a smaller battery option for short trips (48.6kWh for 197 miles of range) and a larger one (64.8kWh) with a 260-mile range. Large, performance-focused vehicles like the Rivian R1T pickup have double or more the battery capacity. Rivian offers three different battery sizes-the standard park (270-mile range, 105 kWh), the large pack (321-mile range, 135 kWh), and the max pack (410-mile range, 180 kWh).
Making matters even more complicated, there are now two main types of EVs on the market. In the past, most US-made EVs had nickel cobalt manganese (NCM) batteries, which are energy-dense and offer high power and range. More recently, automakers have been quietly switching to a new type of battery, called lithium iron phosphate (LFP), in their base models. Tesla, Ford, and Rivian have adopted them because they cost less-no expensive cobalt and nickel-and achieve same EPA-estimated range. However, LFP batteries lose range more quickly in cold weather and have less power. Therefore, NCM batteries are still generally considered a more desirable, premium option reserved for upper-tier trims.
In the end, both battery types still generally follow the same basic principles. Unlike the electricity coming from a typical wall outlet, they put out direct current (DC) power. In order to generate rotational force, that power needs to be converted to alternating current (AC). That’s where the design of an EV’s motor comes in.
The Design of the Motor
An EV’s electric motor doesn’t have to pressurize and ignite gasoline to move the car’s wheels. Instead, it uses electromagnets inside the motor that are powered by the battery to generate rotational force.
Inside the motor are two sets of magnets. One set is attached to the shaft that spins the car’s wheels, and the other is inside the housing surrounding that shaft. Both sets of magnets are charged so that their polarity is the same, and they repel one another. The force of the magnets pushing away from one another turns the shaft, spins the wheels, and moves the car forward.
In order to maintain a constant state of repulsion between the magnets, their polarity has to constantly change as the shaft turns. Otherwise, they’d eventually rotate back to a point where they would attract instead of repel one another and lock themselves in place. AC power does this automatically, constantly alternating between positive and negative. But since the power from an EV’s battery is DC, a device called an inverter is needed to keep flipping the polarity of the magnets.
An EV’s inverter flips polarity quickly, around 60 times per second, to keep the rotational force going. A separate DC converter is used to direct power to other vehicle systems (heating, infotainment, and lighting) that don’t require alternating current. The frequency of the current sent to the motor can be changed by the driver, and the higher the frequency the more frequently the polarity flips. This generates more rotational force, or torque, and spins the wheels faster.
The Art of Charging
With gas-powered cars, you fill up the tank and head out. With EVs, there are three different levels of charging stations in the US, from slowest (level 1) to fastest (level 3).
- Level 1 chargers are typical, 120-volt wall plugs, and are most useful in private homes where you can juice up overnight. It’s slow: An 8-hour charge adds about 40 miles of range; a full charge can take 20 hours or more.
- Level 2 stations step up to 240 volts and output anywhere from 10–25kW for a full charge in about eight hours. This makes them the common solution for overnight charging at home or at locations like hotels. Tesla Level 2 stations are known as Destination Chargers (versus Superchargers). If you don’t have the appropriate plug, a 240-volt outlet or home charging station would need to be installed to recharge an EV at your house.
- Level 3 DC fast charging (DCFC) stations deliver the most power; they can charge an EV battery to around 80% in about 30–60 minutes depending on the station’s charging speed (50–350kWh), the maximum charging speed the vehicle can support, and external factors such as weather (very cold weather can take longer).
All EVs come with a level 1 cord that plugs into the vehicle on one end and a standard wall outlet on the other, save for Tesla, which stopped including level 1 chargers in 2022. This is a great start for new EV owners to juice up while they evaluate whether they need to install a level 2 charger for faster home charging speeds.
Level 3 chargers are not available to install at home, as they draw significant power beyond what a home’s electrical capacity can support. They’re commonly located along highways for road trippers, as well as around town and in the city. Brands like Electrify America, EVGo, and Tesla Superchargers are common. Recently, an increasing number of automakers have announced they will switch to Tesla’s charging port, and will build it into their vehicles after 2025. That will effectively make Tesla Superchargers the go-to stations for many EV buyers.
There’s some debate over whether using level 3 fast-charging stations all the time can have a deleterious effect on your EV’s battery. The jury’s still out on that one, although a recent study found no extra degradation in Teslas that routinely fast charge compared with those that rarely do, Electrek reports. For now, you should probably just use what makes the most sense for you based on where you live and what you can afford.
Given the time it takes to charge, the most optimal approach is to routinely top off the charge throughout the day when parked at home, work, or anywhere else the vehicle is parked throughout the day-at work, running errands, or at the gym. This prevents the battery from losing too much charge throughout the day and means less time charging the vehicle or sitting at a charging station.
EVs also come with a regenerative braking system that harnesses kinetic energy from stopping the car and channels some of it back to the battery pack to be stored as electrical energy. This won’t totally recharge your EV but can make it much more efficient in the right circumstances.
How Far Can an EV Get on a Charge?
The most common EV concern is range anxiety. Will an EV will get the same mileage on a charge as a gas car gets on a full tank? The answer is: It depends.
The average EV range at the time of this writing is 220 miles, according to data aggregated by Electric Vehicle Database. But the upper and lower ends of the spectrum vary widely, from 114 miles on the 2023 Mini Cooper EV (though the next generation Mini Coop may promise more) to the Lucid Air’s 500+ mile range. Multiple variables can affect that range, both in the moment and over the lifetime of the vehicle.
The size of an EV’s battery is one of the most consequential factors when it comes to range. But whatever its capacity, an EV’s range can be reduced by continuous highway driving, frequent quick accelerations, overuse of fast charging, extreme weather, and natural aging over time.
Modern electric cars are becoming a more competitive option every year, causing more drivers to switch to them. In the US, EVs make up 7% of new car sales. In other places, like Europe, they’re up to 21% as of August 2023-and a whopping 85% in Norway. Still, charging infrastructure needs some work. The best case scenario for EV drivers is charging at home and work, which essentially relegates any concept of “making a special trip to fill up the car” a thing of the past.
While they have some kinks to work out, and won’t save us from climate change by themselves, EVs can be part of a larger comprehensive movement to rethink transportation and build greener alternatives.
Originally published at https://www.pcmag.com.
