How electric vehicles work

Electric vehicles have been in use since the automobile era began. The first “horseless carriages” were powered by steam, electricity or liquid fuels. Because electric cars were more simple and reliable, they were more common than gasoline vehicles in the early years of the automobile.

In those early years, cars using liquid fuels produced smelly exhaust fumes, and their piston engines were dangerous to start and prone to problems. But as the availability of gasoline spread and with the invention of the electric starter, gasoline-powered vehicles soon became the dominant form.

Electric propulsion still remained the technology of choice for certain tasks, ranging from cargo handling to mining, particularly in underground settings.

Electric cars are powered by electromagnetic force and electrochemical storage.

Electromagnetic force

Electric motors accept power from batteries in the form of voltage and current. When electric current flows through coils of wires inside a motor, the coils generate magnetism, known as electro-magnetism. When this magnetism reacts against a nearby magnet or a second coil of wire, it produces a force. In a motor, that electromagnetic force is harnessed to rotate the motor’s center shaft, known as its rotor.

Depending on whether the motor uses alternating current (AC) or direct current (DC), the methods for controlling its operation varies. The result, however, is that a mechanical force is created that can be used to move a vehicle.

In a modern electric vehicle, the motor, the gear reducer and the differential are often combined into a single package, as seen here.

Electrochemical storage

The electric power that operates an electric vehicle is provided by a battery, which uses electrochemical energy storage to produce voltage and current.

Batteries use two or more materials that react to create a voltage, often in the presence of an electrolyte. As the materials, usually metals, react with one another, they release electrons, which can be harnessed in an electrical circuit.

In 1859, the lead-acid battery was invented by Gaston Planté and was the first rechargeable battery. This lead-based technology is still widely used today for energy storage needs, including the starting of gasoline powered cars and trucks.

Advanced battery technology is common in modern hybrid and electric vehicles, including nickel-metal hydride and lithium-ion batteries. Regardless of which chemistry is chosen for use in an electric vehicle, the result is the same: electrochemical reactions produce voltage and current, which are harnessed by an electric motor to move the vehicle.

Interested in learning more?

U.S. Department of Energy, Vehicle Technologies Program
Power Electronics and Electrical Machines

How the Tesla Roadster Works, by Ed Grabianowski

How GM’s E-Flex Propulsion System Works, by Patrick E. George

More info on the history of electric vehicles.

More info on the history of the internal combustion engine and early gas-powered cars.