9 Components of Electric Vehicles

People consider battery electric vehicles (BEVs) as the car of the future. They already hold a significant share of the marketplace globally, which will only increase with time. However, their components are completely different from the ones found in regular cars, particularly those with an internal combustion engine.

Nine Components Common to Electric Vehicles

Without further ado, here are nine essential components found in battery electric vehicles.

Electric Vehicle Cutaway
Cutaway of an electric vehicle. (Photo courtesy of U.S. Department of Energy’s Alternative Fuels Data Center.)

1. Electric Motor

Instead of using a regular internal combustion engine, BEVs use an electric motor or several electric motors to propel the vehicle. Instead of regular fuel, like gasoline, they use electricity. Most commonly, electric motors use alternating currents, like the one found in your home, because those motors supply decent efficiency and reliability.

2. Traction Motor Battery Pack

The traction motor battery pack stores electricity used by the electric motor to create traction. Most commonly, the traction motor battery pack utilizes lithium-ion and always houses a direct current. They have a myriad of issues, such as a heavy weight and large volume, along with a fire hazard in case of rupturing. However, when planned solid-state batteries become reliable enough these issues might be fixed to some extent.

3. Transmission

The transmission of a BEV is not the same as the one found on a regular car. They generally do not have multiple gears to shift into and rely on a singular gear. However, this transmission needs a differential like any other car out there, more commonly it is integrated directly into the transmission itself, resulting in a highly compact final unit. It is worth noting that sometimes it is called a speed reducer instead of a transmission.

4. Power Conversion Unit

All BEVs have several power conversion units (PCUs). They are distinct components entirely that do different tasks, and they can either share the same housing or are built separately. One such PCU is the inverter which changes the direct current stored in the traction motor battery pack into alternating current to be used by the electric motors. The other kind of PCU is the convertor that increases or decreases the direct current voltage stored in the traction motor battery pack.

5. Auxiliary Battery Pack

The auxiliary battery pack stores low-voltage direct current that powers the car’s auxiliary systems, such as its interior lights or the infotainment system. A regular 12-volt lead-acid battery is used for this purpose, and it is charged thanks to the convertor described earlier. The traction motor battery pack cannot power these electronics due to the significant voltage difference, with the traction motor battery housing direct current at around 400V.

6. Charge Port

The charge port is the equivalent of the fuel filler neck found on regular cars, but instead of receiving gasoline, it receives direct current. The charger, be it a home charger or a public charger, receives alternating current from the electricity grid and converts it locally into direct current, ready to be stored in the car’s traction motor battery pack.

7. Onboard Charger

Sometimes, the home or public charger does not convert alternating current into direct current. That is usually the case with home chargers. In this situation, the transformation must be done locally with the help of an onboard charger. As expected, this charger is not nearly as powerful as the one found in public charging spots.

8. Thermal System

Despite not having too many moving parts, the traction motor battery pack along with other components becomes quite hot during regular use and even more so during heavy use. With this in mind, to circulate coolant around the vehicle in to cool these components down we need a thermal system. This is the case because, during fast charging, the traction motor battery pack gets increasingly hot, risking severe damage to the unit. Moreover, if the electric components run too hot, their efficiency starts decreasing, eating into the car’s range.

9. Power Electronics Controller

To change the speed of the electric motor you need a power electronics controller by soliciting the battery of the said current; otherwise, the motor will run at a set speed. Moreover, the power electronics controller also permits the electric motor to change its rotation direction, allowing users to engage reverse, and to use the electric motor as a generator, permitting the car to use regenerative braking. Regenerative braking increases the range of the vehicle by around 5- to 10 percent. The power electronic controller usually houses an inverter.

Universal Main Components

These are all the main components found in all battery electric vehicles, regardless of manufacturer. They can also be found on other vehicles, like a plug-in hybrid or a fuel cell electric vehicle, but certainly are not limited to them. It all depends on the manufacturer and what they want to achieve with said platform.


(n.d.). All-Electric Vehicle Basics. NREL.

Figler, S. R. (June 2020). Cooling Systems in Electric Vehicles. Northern Michigan University.

(n.d.). EV Power Systems (Motors and controllers). Advanced Vehicle Testing Activity. Idaho National Laboratory.

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Cristian Puscasu
Author: Cristian Puscasu
Cristian Pușcașu started loving cars and wanted to become a “racing driver” thanks to some computer game that lit the fire almost two decades ago. Since then, he came to his senses and decided that becoming an automotive engineer is more sensible, and pursued such a degree in his home country, Romania. Cristian decided to try writing about what he learned, in an attempt to correct certain misconceptions and to use his degree a bit unconventionally.

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