What's an EV - BEV? 

EV stands for Electric Vehicle. It is an fully Electric Vehicle without any other source of propulsion. An EV must be plugged in to obtain energy to drive the vehicle and has a range limited by the battery pack.  An other explanation for EV is BEV which means Battery Electric Vehicle.

What's an HEV?

Hybrid Electric Vehicle (HEV) work through a combination of an internal combustion engine, a bank of batteries, and an electric motor.  This combination varies from “mild hybrids,” which simply reduce the engine size and boost acceleration with an electric motor to a set up wherein the engine runs only to produce electricity, that then runs an electric motor. 

What's an PHEV?

PHEV is an abbreviation for Plug-in Hybrid Electric Vehicle.  These vehicles, like other Hybrid Electric Vehicles (HEVs) have an onboard internal combustion engine that charges batteries or otherwise provides electricity to an electric motor.  This electric motor either assists the internal combustion engine (in parallel HEVs) or is the sole mechanical link to the wheels (in series HEVs).  What makes a PHEV different from a HEV is its ability to charge the batteries by plugging the vehicle in.  This feature has the advantage of allowing the vehicle to run for some distance without running the internal combustion engine at all—thus reducing the use of petroleum.