Electric and hybrid vehicles: Engineering methods

Battery, plug-in, hybrid, e-scooter or fuel cell compared

What this tab covers The engineering methods that can do this conversion, compared on efficiency, scale, economics, limitations and reliability.

Battery electric cars dominate electrified sales; plug-in hybrids are about a third; full hybrids are a separate, large market led by Toyota; fuel-cell cars remain tiny.

Comparison

Method	Efficiency	Scale	Economics	Limitations	Reliability
Battery electric vehicle (BEV)¹⁴⁵¹¹	65-69% of socket energy to wheels, 87-91% counting regeneration; 70-80% from generated electricity (Volkswagen estimate)	About 65% of the 20 million electric cars sold in 2025	Pack USD 99/kWh (2025); nearly 70% of BEVs sold in China cheaper than combustion equivalents	Charging time, cold-weather range loss, battery mass, upfront cost outside China	Few moving parts; no lifetime or failure-rate data in checked sources
Plug-in hybrid and range-extender (PHEV, EREV)⁴	Between BEV and full hybrid, depending on charging habits (no single figure in sources)	About 35% of electric car sales in 2025, range-extenders under 7%	Premium over petrol cars about 85% in Brazil and 15% in Mexico (2025)	Two drivetrains to pay for and maintain	Combines engine and electric wear items
Full hybrid (HEV)¹⁵⁸¹³¹⁷	Toyota hybrid engine 41% peak thermal efficiency (40% non-hybrid version); idling losses removed	Toyota and Lexus alone sold 4.43 million in 2025	63.94 US cents per mile ownership cost (US, 2025)	Still burns petrol; benefit is smaller on the motorway	Mature since the late 1990s; no failure data in checked sources
E-bikes and e-scooters³¹⁴	72-91% less energy than a 250cc petrol scooter (2019 UK test)	8.4 million electric two-wheelers sold in China and India in 2025; electric three-wheelers over 25% of their sales	No checked cost figure	Range, weather, battery fire risk in poor-quality packs	No checked data
Hydrogen fuel-cell vehicle (FCEV)⁹¹¹⁸	25-35% from renewable electricity to wheels	16,011 sold in 2025 (China 7,797, South Korea 6,802)	No vehicle or hydrogen price in the sources used	Few refuelling stations, costly hydrogen, about two to three times the electricity per km of a BEV (calculated from 25-35% against 70-80%)	No lifetime data in checked sources; outside Korea and China sales are shrinking (Toyota fuel-cell sales down 29% in 2025)

Per kilometre, e-bikes and e-scooters use least energy, then battery cars, then hybrids and plug-in hybrids (depending on charging), then fuel-cell cars, with petrol cars last. Battery cars convert energy once (electricity to motion); hydrogen cars convert electricity to gas and back. Hybrids are the cheapest way to cut fuel use where charging is scarce. Fuel-cell sales figures differ by source (Hyundai 6,861 or 7,047; Toyota 1,168 or 1,257): SNE Research counts registrations by market, while the higher figures match the carmakers' own sales counts.

How each method works

Battery electric vehicle (BEV)

A large lithium-ion pack (typically tens of kWh) feeds an inverter and one or more motors. It is charged from the grid and recovers braking energy.

Plug-in hybrid and range-extender (PHEV, EREV)

A smaller pack gives some electric range, then a petrol engine drives the wheels or a generator. Efficiency depends heavily on how often the owner charges.

Full hybrid (HEV)

An engine tuned for efficiency works with a motor and a small battery that cannot be plugged in. It cuts idling (6% of a petrol car's fuel in city driving) and recovers braking energy.

E-bikes and e-scooters

A small hub or crank motor and battery assist pedalling or drive a two-wheeler; low mass and speed keep energy use tiny.

Hydrogen fuel-cell vehicle (FCEV)

Hydrogen at high pressure feeds a fuel cell stack that makes electricity for a motor, with a small buffer battery. Refuelling takes minutes.

Sources

Where the Energy Goes: Electric Cars US DOE and US EPA (fueleconomy.gov), 2025
Global EV Outlook 2026: Executive summary IEA, 2026
Global EV Outlook 2026: Trends in electric cars IEA, 2026
Lithium-ion battery pack prices fall to USD 108 per kilowatt-hour despite rising metal prices BloombergNEF, 2025
Toyota global sales 2025 (Toyota's sales release as reported, with hybrid, PHEV, BEV and fuel-cell breakdown) Carscoops, 2026
Global H2 vehicle sales rise by nearly 25% (SNE Research data as reported) electrive, 2026
Hydrogen or battery? A clear case, until further notice (company analysis) Volkswagen AG, 2019
Your Driving Costs 2025 fact sheet AAA, 2025
Real-World Scooter Performance Study Cenex, 2019
TNGA powertrain: 2.5-litre Dynamic Force engine (40% and 41% maximum thermal efficiency) Toyota Motor Corporation, 2016
Where the Energy Goes: Gasoline Vehicles US DOE and US EPA (fueleconomy.gov), 2024