A hybrid (HEV) is powered by an electric motor and a combustion engine, either working separately or together. Two energy sources mean lower exhaust emissions than conventional cars. And hybrids can be cheaper to run as they use less fuel.
The different types of hybrid car
Hybrid systems vary by manufacturer. This is a general guide to the three main types of hybrid and how they function.
Mild hybrid (MHEV)
The engine always powers the car, assisted by a powerful electric battery, e.g. when accelerating. This boost from the battery reduces the engine's workload.
Energy otherwise lost when braking is used to recharge the battery.
Mild hybrids are the simplest type of hybrid, so their fuel economy and exhaust emissions are inferior in most situations.
Full hybrid (FHEV)
Full hybrids run on electric power over short distances — the battery takes over from the combustion engine. This lowers fuel consumption and exhaust emissions.
The electric motor sources energy from either the battery or the engine. As with a mild hybrid, full hybrids self-charge by harnessing energy otherwise lost while braking or driving.
Plug-in hybrid (PHEV)
Plug-in and self-charging
Plug-ins take full hybrid technology a stage further – they self-charge but can also be recharged from an external electricity supply.
Their larger batteries mean PHEVs have a longer all-electric range than a full hybrid. But they also cost more to buy.
What is a self-charging hybrid?
Full and mild hybrid models are self-charging. Their batteries are charged using energy created by the combustion engine.
There is no need to plug them in, so you’ll never have to worry about finding or installing a charging station.
Hybrids also recharge themselves through a process called regenerative braking. The car’s kinetic energy — that would otherwise be lost — charges the battery.
A plug-in hybrid can also self-charge. But to be worthwhile, it requires a dedicated mains supply.
On a short journey, in light traffic at modest speeds, and with a light load, a plug-in hybrid could be powered entirely by the battery.
What’s the difference between a hybrid and an ordinary car?
Hybrids use an electric motor to either boost the conventional engine (mild hybrids only), or instead of the engine for short distances. This results in better fuel economy and lower emissions than a conventional car.
What’s the difference between hybrids and electric cars?
An electric vehicle (EV) is powered solely by electricity. It has no combustion engine.
EVs require a mains electricity supply. Unless you have a rapid charger, a full charge can take many hours.
Driving an EV produces no exhaust emissions. However generating electricity for the power grid does create CO2 emissions.
A key difference between EVs and hybrids is that once an EV runs out of charge, it cannot be driven.
As hybrids use two energy sources, there’s no “range anxiety” – the modern phenomena EV drivers face when trying to reach a charging point before their car runs out juice.
The battery of a hybrid car
Hybrid batteries are made from lithium-ion, a material designed to absorb and store energy quickly.
A full hybrid has a larger battery than a mild hybrid, and a plug-in hybrid has the most powerful battery of the three — and also the heaviest.
The bigger the battery the heavier the car.
Energy from the combustion engine recharges the battery, along with regenerative braking.
And a plug-in hybrid can be also recharged from the mains, at home, at work or at a public charging station.
How long does a hybrid battery last?
A hybrid battery is designed to last for the full lifespan of the car. So the battery shouldn’t need replacing in new or good-quality used cars.