Plug-in hybrid

A plug-in hybrid electric vehicle (PHEV) or simply plug-in hybrid is a type of hybrid electric vehicle equipped with a rechargeable battery pack that can be directly replenished via a charging cable plugged into an external electric power source, in addition to charging internally by its on-board internal combustion engine–powered generator. While PHEVs are predominantly passenger cars, there are also plug-in hybrid variants of sports cars, commercial vehicles, vans, utility trucks, buses, trains, motorcycles, mopeds, military vehicles and boats.

Similar to battery electric vehicles (BEVs), plug-in hybrids can use centralized generators of renewable energy (e.g. solar, wind or hydroelectric) to be largely emission-free, or a fossil plant in which case they displace greenhouse gas emissions from the car tailpipe exhaust to the power station. As opposed to conventional hybrid electric vehicles (HEVs), PHEVs generally have a larger battery pack that can be recharged (theoretically) from anywhere with access to the electrical grid, offering enhanced energy efficiency and cost-effectiveness when compared to relying solely on the on-board generator. Additionally, PHEVs can support longer and more frequent all-electric range driving, and their electric motors often have higher power output and torque, are more responsive in acceleration, and overall have lower operating costs. Although a PHEV's battery pack is smaller than that of all-electric vehicles of the same weight, as it must accommodate its combustion engine and hybrid drivetrain, it provides the added flexibility of reverting to the use of its gasoline/diesel engine, akin to a conventional HEV if the battery charge is depleted. This feature helps alleviate range anxiety, particularly in areas lacking sufficient charging infrastructure.

Mass-produced PHEVs have been available to the public in China and the United States since 2010, with the introduction of the Chevrolet Volt, which was the best selling PHEV until it was surpassed by the Mitsubishi Outlander PHEV at the Volt's end of production in 2019. By 2021, BYD Auto emerged as the largest plug-in hybrid vehicle manufacturer in the world. As of May 2024^[update], BYD plug-in hybrid cumulative sales surpassed 3.6 million units. The BYD Song DM line of SUVs contributed over 1.05 million units.

China currently has the largest stock of PHEVs in the world, with cumulative sales of 9.31 million units (including EREV) through December 2024. In 2024, over 76% of global PHEV sales was contributed by the Chinese market. In addition, the five largest producers of PHEVs globally are Chinese manufacturers, which are BYD, Geely, Chery, Li Auto and Changan.

The Lohner–Porsche Mixte Hybrid, produced as early as 1899, was the first hybrid electric car. Early hybrids could be charged from an external source before operation. The term "plug-in hybrid" has come to mean a hybrid vehicle that can be charged from a standard electrical wall socket. The term "plug-in hybrid electric vehicle" was coined by UC Davis Professor Andrew Frank, who has been called the "father of the modern plug-in hybrid".

The July 1969 issue of Popular Science featured an article on the General Motors XP-883 plug-in hybrid. The concept commuter vehicle housed six 12-volt lead–acid batteries in the trunk area and a transverse-mounted DC electric motor turning a front-wheel drive. The car could be plugged into a standard North American 120 volt AC outlet for recharging.

In 2003, Renault began selling the Elect'road, a plug-in series hybrid version of their popular Kangoo, in Europe. In addition to its engine, it could be plugged into a standard outlet and recharged to 95% range in about 4 hours. After selling about 500 vehicles, primarily in France, Norway and the UK, the Elect'road was redesigned in 2007.

With the availability of hybrid vehicles and the rising gas prices in the United States starting around 2002, interest in plug-in hybrids increased. Some plug-in hybrids were conversions of existing hybrids; for example, the 2004 CalCars conversion of a Prius to add lead acid batteries and a range of up to 15 km (9 mi) using only electric power.