Types of Electric Vehicles and Hybrid Vehicles: Pros and Cons

The transport industry is adopting battery-electric, hybrid and fuel cell technologies to improve energy efficiency, reduce fossil-fuel use and support lower-emission mobility. These are often grouped under the broader term electrified vehicles, although their powertrains and infrastructure requirements differ substantially.

What Are Electric Vehicles?

In strict engineering terms, an electric vehicle uses one or more electric motors for propulsion. Battery-electric vehicles rely entirely on stored electrical energy, while hybrid and fuel cell vehicles also use electric traction but obtain energy in different ways. For clarity, these categories are often described collectively as electrified vehicles.

Electrified vehicles can offer quiet operation, high drivetrain efficiency and reduced tailpipe emissions, depending on the technology. Charging or refuelling infrastructure, range, energy use, capital cost and operational suitability vary significantly between vehicle types.

Types of Electrified Vehicles

There are several common electrified powertrain types, each with a different energy source and degree of electrification.

Battery Electric Vehicles

Battery-electric vehicles, commonly known as BEVs, operate entirely using electricity stored in a rechargeable traction battery. They do not use a conventional combustion engine for propulsion and require external charging.

Hybrid Electric Vehicles

Hybrid electric vehicles combine an internal combustion engine with an electric motor and battery. The electric system can assist the engine and recover energy through regenerative braking, helping improve fuel efficiency in suitable duty cycles.

Plug-In Hybrid Electric Vehicles

Plug-in hybrid electric vehicles have a larger battery that can be charged from an external power source. They can normally travel a greater distance using electric power alone than a non-plug-in hybrid before the combustion engine is required.

Fuel Cell Electric Vehicles

Fuel cell electric vehicles use hydrogen in a fuel cell stack to generate electricity for an electric drivetrain. A traction battery is normally used alongside the fuel cell for transient power demand and regenerative braking. Water and heat are the main by-products of the fuel cell reaction at the vehicle level.

Hybrid Vehicles: Pros and Cons

Understanding the pros and cons of hybrid vehicles is important when comparing hybrid technology with conventional, battery-electric and fuel cell vehicles.

Advantages of Hybrid Vehicles

Hybridisation can improve fuel efficiency by allowing the electric motor to assist the combustion engine, optimise engine operation and recover braking energy. The benefit depends on vehicle design and duty cycle.

Hybrid vehicles can recover part of the vehicle's kinetic energy through regenerative braking and store it in the battery for later use.

Another benefit is operational flexibility. Conventional hybrids do not require external charging and can use established fuel-refuelling infrastructure; plug-in hybrids can also use externally supplied electricity.

Disadvantages of Hybrid Vehicles

Hybrid powertrains combine combustion and electric systems, so maintenance and diagnostic requirements differ from both conventional and battery-electric vehicles. Reliability and whole-life maintenance cost depend on the specific design, duty cycle and manufacturer support.

Hybrids can also have a higher purchase price than comparable conventional vehicles. Whether this is offset over the vehicle life depends on fuel savings, maintenance, residual value, duty cycle and energy prices.

Because conventional hybrids retain an internal combustion engine, they continue to produce tailpipe emissions and do not meet the same zero-tailpipe-emission definition as BEVs or FCEVs.

Choosing the Right Technology

The appropriate technology depends on the duty cycle, budget, infrastructure, range requirement, emissions objective and total cost of ownership. For buses in particular, route-level energy modelling and infrastructure planning are essential before selecting a powertrain.

As technology develops, battery-electric, hybrid and fuel cell systems will continue to serve different parts of passenger and commercial transport. Understanding their engineering and operational differences helps buyers and operators select the most suitable solution.