EV 101: How do electric cars work?

as manufacturing costs decline(Opens in a new window) and charging infrastructure improves, electric vehicles (EVs) have become a more attractive purchase for American drivers looking to avoid sky-high gas prices or mitigate the environmental impact of gasoline-powered vehicles. But how do they really work?

The basics of electric cars

Audi Q5 55 TFSI E Quattro 2021 Review

2021 Audi Q5 55 TFSI E Quattro (Photo: Audi)

Unlike a typical internal combustion engine (ICE) vehicle that runs on gasoline, electric vehicles do not require explosive combustion through burning fuel to generate the energy needed to move. Instead, they use the 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, electric vehicles have fewer moving parts than a gasoline vehicle and generally require less maintenance, although they currently have a higher initial cost.

There are several different types of vehicles that could qualify as EVs, a spectrum of cars from plug-in hybrids with small supplemental batteries to fully electric vehicles powered by batteries and even cars powered by hydrogen fuel cells.

Most of the electric vehicles you’ll see on the road today are either hybrids like the Toyota Prius or fully electric vehicles like the Tesla Model 3. We’ll focus specifically on how fully electric vehicles work here.

The science behind the battery

fully electric vehicle

Electric vehicle interior (Image: Alternative Fuels Data Center/US Department of Energy)

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 conditioner. You’ll also hear this called a traction battery, and it’s usually located in the bottom of the vehicle.

An electric car battery is charged in the same way as the lithium-ion battery in your cell phone, only on a much larger scale. You connect it to the network through an outlet or a charging station, and it draws energy until it charges. The amount of energy an EV battery can hold will depend on its capacity, measured in kilowatt-hours (kWh). The higher the number, the greater the capacity and the farther that electric vehicle can drive on a single charge.

Not all electric vehicles have the same battery. smart equalizer(Opens in a new window) Mercedes-Benz models, for example, have battery capacities of 16.7kWh, giving them about 60 miles(Opens in a new window) range on a single charge. the Tesla Model S Long Range(Opens in a new window), on the other hand, has a 95kWh battery and an estimated range of 350 miles. Battery technology for electric vehicles is constantly evolving, so we could see vehicles with longer ranges and shorter recharge times on the market in the coming years.

Unlike the electricity that comes from a typical wall outlet, batteries put out direct current (DC) power. To generate rotational force, that power must be converted into alternating current (AC). That’s where the design of an EV’s engine comes into play.

engine design

An EV’s electric motor doesn’t have to pressurize and ignite gasoline to move the car’s wheels. Instead, it uses battery-powered electromagnets inside the motor to generate rotational force.

Inside the motor there are two sets of magnets. One set is attached to the axle that turns the car’s wheels, and the other is inside the housing that surrounds that axle. Both sets of magnets are charged so that their polarity is the same and they repel each other. The force of the magnets moving away from each other rotates the axle, turns the wheels, and moves the car forward.

In order to maintain a constant state of repulsion between the magnets, their polarity must constantly change as the shaft rotates. Otherwise, they would eventually rotate back to a point where they would attract rather than repel each other and lock in place. AC power does this automatically, constantly alternating between positive and negative. But since an EV’s battery power is DC, a device called an inverter is needed to keep changing the polarity of the magnets.

An EV’s inverter changes polarity rapidly, about 60 times per second, to maintain rotational force. A separate DC converter(Opens in a new window) it is used to direct power to other vehicle systems (heating, infotainment, and lighting) that do not require AC power. The controller can change the frequency of the current sent to the motor, and the higher the frequency, the more frequently the polarity changes. This generates more rotational force, or torque, and spins the wheels faster.

The art of charging

ChargePoint Home Flex Electric Vehicle Charger

ChargePoint Home Flex Electric Vehicle Charger

With gasoline cars, you fill up the tank and go. With EVs, there are three different levels of charging stations in the US, from the slowest (level 1) to the fastest (level 3).

  • Level 1 Chargers are typical, 120-volt wall plugs, and are most useful in private homes where you can charge power overnight. It’s slow: an 8-hour charge add(Opens in a new window) about 40 miles of range; a full charge can take 20 hours or more.

  • Level 2 stations boost up to 240 volts and generate between 10 and 25 kW for a full charge in about eight hours. This makes them the common solution for overnight charging at home or in places like hotels. Tesla Level 2 stations are known as destination chargers(Opens in a new window) (versus superchargers). If you don’t have the proper plug, you’ll need to install a 240-volt outlet or home charging station to recharge an electric vehicle at home.

  • Level 3 DC Fast Charging (DCFC) stations provide the most power; they can charge an electric vehicle battery up to around 80% in about 30 minutes. They offer 50kW on average, although there are some that channel even more power to the battery, like Tesla’s superchargers.

tesla supercharger

Tesla level 3 supercharger station in Beaver, Utah, charging up to 250 kW. (Photo: Chloe Albanesius)

there are some discussion(Opens in a new window) about whether using Level 3 fast-charging stations all the time can have a detrimental effect on your EV’s battery. the jury still outside(Opens in a new window) in that; For now, you should probably use what makes the most sense for you based on where you live and what you can afford.

Most electric vehicles come with a power cord that can be plugged into level 1 and level 2 charging stations, the two most common charging levels you’ll find. Teslas also come with an adapter that can be used at non-Tesla stations (mobile chargers no longer included). Most public charging stations will have a group of connection ports that deliver level 2 and level 3 power.

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Instead of draining the battery and filling it up all at once, many EV drivers recharge the battery while 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.

Electric vehicles also come with a regenerative braking system that harnesses the kinetic energy of stopping the car and channels some of it back to the battery pack for storage as electrical energy. This will not fully recharge your electric vehicle, but it can make it much more efficient under the right circumstances.

How far can an electric vehicle go on a charge?

Grand tourer Lucid Air

Lucid Air Grand Touring has an estimated range of 516 miles (Photo: Lucid Motors)

EV’s most common concern is range anxiety. Will an electric vehicle get the same mileage on a charge as a gasoline car with a full tank? The answer is, it depends.

The average EV range at the time of writing is 200-250 miles(Opens in a new window) on a single charge, based on data aggregated by the Electric Vehicle Database. But the upper and lower ends of the spectrum vary widely, from 50 miles to more than 300 (the Lucid Air promises(Opens in a new window) more than 500 miles). Multiple variables can affect that range, both at the time and over the life of the vehicle.

tesla model 3 charging on a phoenix supercharger

Tesla Model 3 charging at a Phoenix Supercharger. (Photo: Chloe Albanesius)

The size of an electric vehicle battery is one of the most important factors when it comes to range. But whatever its capability, an EV’s range can be reduced by continuous highway driving, frequent rapid acceleration, excessive use of fast charging, extreme weather conditions, and natural aging over time.

Modern electric cars are quite competitive with gasoline vehicles, and are becoming more so every year. Their range is already comparable to that of an average gasoline car, and charging infrastructure is abundant enough in many areas that electric vehicles are becoming a viable option for drivers looking for low-emission vehicles. Electric vehicles have some problems to solve and they won’t save us from climate change on their own, but they can be part of a broader comprehensive movement to rethink transportation and build greener alternatives.

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