PHEV (Plug-in Hybrid Electric Vehicle)

A plug-in hybrid electric vehicle is a car that can run independently on fossil fuels and electricity. In the case of a plug-in hybrid, it is important that the vehicle is equipped with a traction battery that can be recharged from the electricity grid.

The abbreviation PHEV (Plug-in Hybrid Electric Vehicle) denotes a plug-in hybrid electric vehicle equipped with both an internal combustion engine and an electric motor. It thus meets the definition of a hybrid vehicle, as it utilizes two types of propulsion. PHEV, in simplified terms, allows combining driving with the internal combustion engine and driving with the electric motor. Both propulsion systems can operate independently or cooperate. Everything is controlled automatically by the vehicle’s electronics according to current needs, or the driving mode is influenced by the driver’s discretion. For example, the driver can choose exclusively electric propulsion for a short trip to work, or even with a depleted battery, reach a distant destination thanks to the combustion engine.

A key aspect in the definition of a PHEV vehicle is that it belongs to the category of so-called “plug-in hybrids”. The traction batteries of PHEV vehicles can be charged directly from the electrical grid using a cable, which is an important difference compared to other types of electro-hybrid vehicles, such as HEV, MHEV, and microhybrids.

One of the key features of PHEV vehicles (plug-in hybrids) is the enhanced electric component compared to fully hybrid vehicles like HEV. This means they have a stronger electric motor and a traction battery with greater capacity. With a larger battery, PHEV vehicles can travel approximately 100 km on pure electric power, depending on the specific vehicle type.

Functioning Principle of PHEV:

There are several technical solutions for the construction of PHEV vehicles. However, common elements include that PHEV vehicles can be charged from the electrical grid and meet the definition of a hybrid motor vehicle. A hybrid motor vehicle has at least two energy converters (two different engines) and two different energy storage systems (batteries/tanks). Thanks to two energy sources, PHEV vehicles can combine driving modes differently according to current requirements. Examples of driving modes can be found in the following gallery:

Plug-in hybrid vehicles (PHEV) are essentially electric hybrids (HEV) supplemented with a larger battery that can be charged from the electrical grid. Compared to hybrids, PHEVs have a reinforced electric component, meaning PHEVs can drive for a longer period solely on electric power.


A typical traction battery of a plug-in hybrid vehicle utilizes 400 V technology, has a capacity of 10–30 kWh, and a weight of 100–200 kg for the PHEV battery. Such technical solutions today enable a range of 50–120 km solely on electric power from the battery. Newer generations of PHEVs have increasingly longer ranges. It’s also noteworthy that the first generation of PHEVs typically didn’t have the option for fast charging with direct current.


A typical combustion engine of a plug-in hybrid vehicle is usually a gasoline engine because it runs smoother, with lower vibrations, heats up faster, and produces fewer nitrogen oxides (NOx). PHEVs typically use a combination of different combustion cycles (typically Atkinson or Miller) to achieve the lowest fuel consumption possible. The drawbacks of the Atkinson cycle, such as lower power and torque, are compensated for by the electric drive of the PHEV.

Advantages of PHEV Vehicles:

  • Due to the possibility of using various drive combinations, PHEVs have lower fuel consumption and related lower emissions of CO2
  • Better dynamics of PHEV vehicles – a combination of the advantages of electric and combustion engines
  • The possibility of charging the battery from an electrical grid, which is not possible with HEV or MHEV
  • The possibility of regenerative braking
  • The possibility of silent and locally emission-free operation up to a distance of around 100 km

* The above-mentioned advantages depend on the way the vehicle is used. It is especially important to properly charge the battery and utilize the vehicle. If you drive long distances and do not charge the battery from the grid, it is highly likely that you are carrying only a burden in the form of an unused traction battery. Although the vehicle charges the battery through regenerative braking, it does so minimally. For such use of the vehicle, HEV is more suitable, as it does not have such a large and heavy traction battery.

Disadvantages of PHEV Vehicles:

  • Higher kerb weight of the vehicle
  • More complex construction, which may result in higher failure rates and service and repair costs
  • Higher purchase price

Did you know …

One of the pioneers in PHEV technology is Toyota

Toyota is one of the pioneers in plug-in hybrid vehicle (PHEV) technology. This automaker introduced one of the first mass-produced plug-in hybrid vehicles in the world – the Toyota Prius Plug-in Hybrid. The first generation of this model appeared in 2012. Toyota also was the first to offer solar roof as an optional feature. In the first generation, this roof supported the consumption of onboard electronics or powered a fan that cooled the car standing in the sun. In 2023, Toyota introduced an improved solar roof for the Prius model, which can now contribute to charging the traction battery. According to Toyota, this roof can generate enough energy daily for a range of up to 8 kilometers or fully charge the battery if the car is parked for several days.

 Toyota Prius equipped with solar panels roof

PHEV Can Be Used as a Mobile Power Source

Another interesting fact about plug-in hybrid vehicles (PHEVs) is their ability to function as mobile power sources in case of power outages or for additional energy use. Systems such as Vehicle-to-Load (V2L) and Vehicle-to-Home (V2H) allow PHEVs to share energy from their batteries with other appliances or even an entire household. For example, the Mitsubishi Outlander PHEV was one of the first cars to offer this technology. However, its use depends on the legislation and technical parameters of the electrical distribution network of a given country, so this service is not automatically available at all times. If the service is available, a PHEV can provide electrical energy to households in emergency situations or serve as a mobile power source. PHEVs can thus play a role not only in transportation but also as part of home energy solutions and backup systems.