PHEV stands for Plug-In Hybrid Electric Vehicle. PHEVs have a gas engine and an electric motor (or motors) powered by a battery that can be charged by plugging it in.

Plug-In Hybrid Vehicles (PHEVs) reduce total fuel consumption by combining two sources of power: an electric motor (or motors), and a gas engine. Typically, the vehicle runs on electric power first; once battery power is depleted, the vehicle will run on gas power alone until a sufficient battery charge is reached through plugging in the battery to recharge.

A Hybrid vehicle does not plug in to recharge the battery; instead, it continuously recharges the battery via regenerative braking and through operation of the engine.
In addition to regenerative braking and engine function, a Plug-In Hybrid (PHEV) battery can be recharged by plugging it in. A PHEV also has a larger battery capacity than a typical Hybrid vehicle, and can therefore drive zero-emission electric mode for longer before the combustion engine takes over. This results in overall lower tailpipe emissions than a regular Hybrid vehicle.

Regenerative braking collects and stores the kinetic energy used to stop the vehicle, and uses it to both charge the battery and help the gas-powered internal combustion engine to drive the vehicle. Just through normal driving, slowing down, and stopping, you contribute to the battery charge.

A PHEV requires gas to function properly, even when driving with zero-emission all-electric power. You should never drive without gas in the tank of your PHEV.

The total range of a Plug-In Hybrid Electric Vehicle (PHEV) depends on the vehicle's battery capacity and fuel tank capacity.