How Electric Cars Work
So, how does an electric car work? Let’s start with the basics: the battery, electric motor, charge port and onboard charger.
The battery is the physically largest component and arguably the most important. The “traction battery pack” stores all of the electrical energy needed by the car and powers its components. Most modern electric vehicle (EV) batteries are made from lithium because they can store high levels of energy while also remaining relatively lightweight. Assuming every EV has the same electrical efficiency, it would be fair to say that a bigger battery means more electric range. Because they run only on electricity, battery electric vehicles (BEVs) tend to have the largest batteries, followed by plug-in hybrid electric vehicles (PHEVs) then hybrid electric vehicles (HEVs).
Using the electrical energy stored inside the battery pack, the electric traction motor converts that energy into mechanical energy. The vehicle’s electric transmission then transfers mechanical energy from the motor to drive the wheels. Depending on the number and placement of these motors, a BEV’s drivetrain can either be front-wheel drive (FWD), rear-wheel drive (RWD), or all-wheel drive (AWD).
The electric motor inside a BEV is also responsible for a useful energy recovery mechanism called “regenerative braking.” This occurs when the driver takes their foot off the accelerator pedal, causing the motor to act in reverse and convert the car’s forward motion ("coasting” in gasoline cars) into electrical energy. The energy is then stored in the battery and ready to power the motor again. In other words, this mechanism is able to recover energy that would otherwise be wasted and direct it into the battery so that the car can use it again the next time the driver needs power.
If you would like to read a more in-depth discussion on how electric motors work, feel free to skip ahead to “Breakdown of Electric Car Motors.”
Charge Port & Onboard Charger
In both BEVs and PHEVs, the battery pack is charged using an external power source. To recharge, a charging plug is inserted into the car’s charge port. Think of the charging plug as the EV equivalent of a fuel nozzle at a gas station. Similarly, the charge port is the EV equivalent of a gas cap – where a fuel nozzle is inserted during refueling.
Working in tandem with the charge port is the onboard charger. Think of this as the computer system responsible for converting the charging plug’s electrical current into an acceptable power level to charge the battery. Whether it’s AC (Alternating Current) – the power found in home wall outlets – or DC (Direct Current) – the power used at public fast charging stations – the onboard charger does the thinking and converting so the driver doesn’t have to. This ensures the battery is not harmed accidentally by using the wrong type of charger.