A traction battery (shown above) is an electrochemical battery which is designed to power an electric drivetrain in an electric or hybrid vehicle.

Traction batteries usually use nickel metal hydride (NiMH) or lithium ion (Li-ion) technology. The next generation of traction batteries will use lithium-sulphur (Li-S) technology.

Because of the large size and heavy weight of traction batteries, they are usually mounted low down in the vehicle in the centre tunnel or behind the rear seats.

The term traction battery is used to avoid confusion with the the much smaller and lower-voltage lead acid battery used to power electrical ancillaries and to start the engine of a hybrid vehicle.