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About this book

This volume of "Encyclopedia of Sustainability Science and Technology, Second Edition," covers the electrification of vehicles, which is key to a sustainable future of transportation in both light-duty and heavy-duty vehicle sectors to address global concerns of climate change, air pollutant emissions, energy efficiency and energy security. Vehicle electrification includes several existing and emerging technologies and powertrain architectures such as conventional hybrid electric vehicles (HEVs), plug-in hybrids with various electric driving range, short- and long-range battery electric vehicles, as well as hydrogen fuel cell electric vehicles (FCEVs). Electrification will be key to connected autonomous vehicles, which are perceived to improve mobility, increase safety, reduce energy consumption and infrastructure costs, improve productivity, decrease traffic congestion and increase customer satisfaction. While electrification of vehicle technologies is relatively mature, technology improvement and economies of scale are needed to compete against incumbent technologies and to realize their benefits in the marketplace. Significant infrastructure development is needed in the case of hydrogen fuel cell vehicles and to a lesser extent for plug-in electric vehicles.
Vehicle efficiency improvement is sought through a combination of several approaches, including weight reduction, engine downsizing, increased engine compression ratio with high octane fuels, and the use of compression ignition engines with low octane fuels. Liquid hydrocarbon fuels are needed in applications where high storage energy density is required such as long-haul class-8 combination heavy-duty trucks. Shared mobility is another emerging concept that enables access to transportation services on an as-needed basis. This approach can enhance accessibility to transportation, decrease number of vehicles on the road, reduce energy use and impact on the environment, reduce cost of transportation and the need for parking, and reduce transportation time between origin and destination. In all, the reader will receive a comprehensive introduction to electric vehicles and technology trends, including energy storage, in light-, medium-, and heavy-duty sectors, as well as the infrastructure development that will be required to realize these benefits for society.

Table of Contents


Electric, Hybrid, and Fuel Cell Vehicles: Introduction

Without Abstract
Amgad Elgowainy

Sustainable Transportation

Conventional vehicle
A vehicle with an internal combustion engine alone.
Electric vehicle
A vehicle with an electric motor and a battery bank for propulsion.
Hybrid vehicle
A vehicle having a combination of internal combustion engine and electric motor for propulsion.
Organic fuels consisting mainly of hydrogen and carbon atoms from fossil or other sources.
Compatible with long-term life on earth.
Vehicle and fuel technology complex.
Mehrdad Ehsani

Internal Combustion Engines, Alternative Fuels for

Advanced biofuel
Renewable fuel not produced from food crops such as cellulosic biofuel and biomass-based diesel.
Alternative fuel
A fuel that can serve or be used in place of another or an unconventional fuel choice.
Diesel gallon equivalent (DGE)
The amount of alternative fuel required to match the energy content of 1 gal of diesel fuel.
Gasoline gallon equivalent (GGE)
The amount of alternative fuel required to match the energy content of 1 gal of gasoline.
Mixture calorific value
The amount of energy contained per volume of fresh charge typically at stoichiometric conditions that can be introduced into the cylinders of an internal combustion engine.
Renewable fuel
A fuel created from resources that are never used up or can be replaced by new growth.
Thomas Wallner, Scott A. Miers

Vehicle Dynamics and Performance

Braking forces
The forces acting on the contact area of the running wheels and ground, generated by the brake system.
Braking performance
The vehicle behavior underlying braking, braking distance, and direction stability.
Braking system
A vehicle subsystem that is used to slow the vehicle quickly.
Fuel consumption
Fuel consumed in unit traveling distance.
Power plants
The machines that supplies power for propelling vehicle.
Tractive effort
The thrust force acting on the contact area of running wheels and ground that push the vehicle forward.
Mechanical devices that transmit the powers of the power plants to vehicle wheels.
Vehicle performance
The capability of a vehicle, in terms of speed, acceleration, and gradeability.
Vehicle resistance
The forces that is against the vehicle motion.
Yimin Gao

Life-Cycle Analysis of Vehicle Lightweighting: A Review

Without Abstract
Jarod C. Kelly, Qiang Dai

Vehicle Biofuels

Methyl or ethyl ester of fatty acids.
Biological material from living or recently living organisms.
The liquid resulting from biomass pyrolysis.
Equivalence ratio
The actual oxygen fed to the reactor divided by the stoichiometric oxygen needed for complete combustion.
A mixture of gasoline and ethanol, typically 90% gasoline and 10% ethanol.
Biomass composed of lignin, cellulose, and hemicellulose.
Oleaginous microorganisms
Microorganisms that accumulate triacylglycerol (TAG) within their cells.
Hydrolysis of polysaccharides to produce sugar.
Synthesis gas
Mixture of carbon monoxide and hydrogen.
Triacylglycerol (TAG)
A natural product containing three fatty acids linked to glycerol via ester bonds.
Mark Holtzapple

Electric, Hybrid Electric and Fuel Cell Vehicles, Architectures of

The mechanical and/or electrical structure that defines the energy flow routes in a vehicle.
Electric coupling
The method by which two electric powers are added together.
Electric vehicle
An electric vehicle is referred to as a vehicle that uses electric energy as its energy source, generally chemical batteries and/or ultracapacitors and electric motor as its power source.
Fuel cell vehicle
A fuel cell vehicle is referred to as a vehicle that uses fuel cells and electric motor as its power source.
Hybrid electric vehicle
A hybrid electric vehicle is referred to as a vehicle in which two energy sources and correspondingly two power sources are installed, which are selectively used to power the vehicle. The primary energy source and power source may be chemical fuels and internal combustion engine. The secondary energy source and power source maybe chemical batteries and electric motor.
Mechanical coupling
The method by which two mechanical powers are added together.
Operation mode
Drive train operation status in which power sources are selectively used as the active power mover to propel the vehicle.
Yimin Gao

PHEVs and BEVs in Coupled Power and Transportation Systems

Battery electric vehicle.
Demand side Management; utility-sponsored programs to influence the time of use and amount of energy use by select customers.
Grid-to-vehicle; using the electrical grid to charge the battery of a vehicle.
Hybrid electric vehicle.
Outage management; set of manual and/or automated procedures used by operators of electric distribution systems to assist in restoration of power.
Plug-in hybrid electric vehicle.
Vehicle-to-building; exporting electrical power from a vehicle battery into a building.
Vehicle-to-grid; exporting electrical power from a vehicle battery to the electrical grid.
Mladen Kezunovic, S. Travis Waller

Plug-in Hybrid Electric Vehicles

All-electric range
Charge depletion
Charge-depletion range
Charge sustaining
Depth of discharge
Electric vehicle
Hybrid electric vehicle
Plug-in hybrid electric vehicle
Mehrdad Ehsani

Fuel Cell-Powered HEV Design and Control

Without Abstract
E. Ubong, J. Gover

Energy Consumption of Connected and Automated Vehicles

Without Abstract
Mascha Brost, Özcan Deniz, Ines Österle, Christian Ulrich, Murat Senzeybek, Robert Hahn, Stephan Schmid

Sustainable Vehicle Fuels, Well-to-Wheel Analysis

Without Abstract
Amgad Elgowainy, Michael Wang, Krishna Reddi

Hybrid Electric and Hybrid Hydraulic Technology Applications in Off-Road Vehicles

Without Abstract
M. Abul Masrur, Vijay K. Garg

Hybrid Energy Storage Systems for Vehicle Applications

Without Abstract
Mehrdad Ehsani, Ramin Tafazzoli Mehrjardi, Nima Farrokhzad Ershad

Vehicle Energy Storage: Batteries

A string of rechargeable electrochemical cells.
Battery electric vehicle
An electric vehicle in which the electrical energy to drive the motor(s) is stored in an onboard battery.
The electrical charge that can be drawn from the battery before a specified cut-off voltage is reached.
Depth of discharge
The ratio of discharged electrical charge to the rated capacity of a battery.
Electric vehicle
A vehicle in which propulsion torque is delivered exclusively by one or more electric motors.
Energy capacity
The electrical energy that can be drawn from the battery before a specified cut-off voltage is reached.
Fuel cell electric vehicle
An electric vehicle in which the propulsion energy is delivered from an onboard fuel cell and battery hybrid system.
Hybrid electric vehicle
A vehicle in which propulsion energy is provided from two or more kinds or types of energy stores, sources, or converters, and at least one of them delivers electrical energy.
Open circuit voltage
The difference of electrical potential between two terminals of a battery when no external load is connected.
Vehicle energy source
The onboard energy storage device of a vehicle.
Y. S. Wong, C. C. Chan

Batteries, Battery Management, and Battery Charging Technology

Alternating current (AC)
Usually in the form of a sine wave, the bidirectional current flow continually reverses. Typically, AC will have a zero mean (average) and a nonzero RMS value. In the USA, most “grid” electricity is generated and distributed in the form of 60 Hz sinusoidal waveform. In other areas of the world, 50 Hz is commonly used.
Amp-hour (Ah)
A unit of electric charge, the amount of current delivered for 1 h.
A group of one or more cells electrically connected in series and/or parallel combinations to achieve higher voltage or current than what is capable from a single cell.
Battery management system (BMS)
An electronic device or system that monitors and controls a rechargeable battery. Parameters measured may include cell temperature, voltage, and current. From this data, the BMS can compute the state of charge of the battery and estimate the state of health, remaining cycle lives, or remaining service life. Typically, a BMS system will include the ability to communicate with a host system and battery charger. The BMS may also contain sensors and circuitry for protection such as over-current, over-temperature, or over-voltage.
Battery pack
A group of batteries or individual cells electrically connected in series and/or parallel combinations along with the required electrical interconnections, mechanical packaging, thermal management, and sensing circuitry. Because it is a self-contained assembly, a battery pack can be easily swapped in and out of the application.
Battery string
Series-connected batteries used to produce a higher voltage. The same current passes through all the cells, but each cell voltage can vary. Charge balancing becomes a significant issue for a long string of 50 or more cells.
The rate at which a battery can deliver or accept current, stated in terms of the rated capacity of the cell in amp-hours. This may also be referred to as the hour rate, such as the 1-h rate.
An individual electrochemical device that converts between chemical energy and electrical energy. The cell construction, open circuit voltage, energy, and power density, all depend on the chemistry of the cell (see section “Battery Chemistries”).
Coulombic efficiency
Ratio of charge delivered by a rechargeable battery during discharge cycle to the charge stored during charge cycle.
Depth of discharge (DoD)
An alternate method to indicate the state of charge of the battery; it is the reciprocal of SoC.
Direct current (DC)
Unidirectional current that continually flows only in one direction. Sources such as batteries, fuel cells, and solar cells produce electricity in the form of direct current.
Memory effect
An effect observed particularly in nickel cadmium batteries in which the cells gradually lose capacity when subject to repeated partial discharges followed by complete recharges cycles. This electrochemical effect is different than the loss of capacity due to aging and use. In some cases, a series of full discharge/recharge cycles can restore some or all of the lost capacity due to the memory effect but not due to cycle life or aging.
Proportional-integral (PI) controller
A type of linear feedback control in which an error signal is calculated as the difference between a measured signal and the desired reference set point. The controller attempts to adjust the operation of the process using a weighted combination of the present error (proportional term) and accumulated past error (integral term).
Primary battery
One-time-use batteries not capable of being recharged. They are discarded or preferably recycled once the stored energy has been depleted. These types of batteries will not be considered in this article.
Root mean square (RMS)
A scalar quantity that is computed from the square root of the sum of the squares of a dataset and is commonly used to represent a voltage or current over one cyclical period. Average power is the product of the RMS current and RMS voltage.
Secondary battery
Commonly referred to as rechargeable batteries, they can be repeatedly recharged electrically by passing current through them in the opposite direction to that of the discharge current. Secondary batteries are of significant interest for their ability to store and supply energy and are the focus of this article.
Self-discharge rate
The rate at which a battery discharges, or looses stored energy, due to internal cell reactions.
SLI batteries
Starting, lighting, and ignition (SLI) batteries are used in automobiles. These batteries are usually characterized by a high discharge rate.
State of charge (SoC)
Defined as the capacity left in a battery expressed as a percentage of some reference. SoC of a battery is usually expressed as a percentage of the current battery capacity when it is fully charged.
State of health (SoH)
A metric that reflects the general condition of a battery and its ability to deliver the specified performance compared with a fresh battery. It takes into account factors such as charge acceptance, internal resistance, voltage, and self-discharge. It is an estimate rather than a measurement.
Watt-hour (Wh)
A unit of energy, the amount of power delivered for 1 h. It is equivalent to 3,600 Joules of energy.
Robert S. Balog, Ali Davoudi

Battery Technologies

The demand for high performance and long life storage systems has lead to numerous research initiatives, aimed at the development of such systems. Developmental paths are aligned with the requirements of the applications of these systems. A detailed understanding of technical characteristics and cost considerations is provided in this paper for various battery chemistries: contemporary, vintage, and prospective. A clear understanding of battery characteristics is essential for guiding the selection of such batteries. Indeed, because of the critical functions fulfilled by batteries as well as the substantial costs of advanced batteries, a realistic appraisal of candidate battery performance and costs against requirements is key to judging the prospects of new applications such as EV, HEV, and plug-in hybrid electric vehicles (PHEV). Although electric vehicles (EVs) have been around since before 1900 the limitations of the batteries to drive them have not enabled them to compete in the general consumer’s market with the internal combustion engine. Automotive parts are limited by space and weight. Therefore EVs and hybrid electric vehicles (HEVs) require a battery with high energy density. Specific energy is defined as the energy per kilogram of the battery while energy density is the energy per unit volume. Early designs (1990–1995) of lithium-ion batteries only had a specific energy of 0.2 kWh/kg. EVs also require a battery with high power output for large power draw, such as quick acceleration. The General Motors EV1 had a battery pack weighing almost 600 kg while the car weighed 1,350 kg. The battery would then account for more than 44% of the car’s weight. A marked improvement in energy cell density of batteries was required for practical EVs.
Ramakrishnan Mahadevan, Mohit Chhabra, Puneet Pasrich, Frank Barnes

Lithium-Ion Batteries for Automotive Applications: Life Cycle Analysis

Without Abstract
Qiang Dai, Jarod C. Kelly

Energy Storage: Ultracapacitor

Without Abstract
Andrew Burke

Regenerative Braking

Antilock braking system (ABS)
Safety system that prevents the wheels on a vehicle from locking up while braking.
Technology to replace the traditional mechanical and hydraulic control systems with electronic control systems using electromechanical actuators and human–machine interfaces.
Brake controller
A microchip-based device which receives brake strength command from driver and feedback signals and generates control signals to control the mechanical and electric brake systems.
Braking energy
The energy consumed by the brake system of a vehicle.
Hybrid brake system
A vehicle brake system that uses both regenerative braking and mechanical fictional brake.
Regenerative braking
Braking device of a vehicle which can absorb vehicle braking energy and store the absorbed braking energy into an energy storage and then uses it for later traction.
Yimin Gao

AC Machines: Permanent Magnet Synchronous and Induction Machines

Field-oriented control
Field-oriented control was introduced in the beginning of 1970s. It demonstrated that an induction motor or synchronous motor could be controlled similar to that of a separately excited DC motor by the orientation of the stator mmf or current vector in relation to the rotor flux to achieve a fast dynamic response in the electromagnetic torque.
Induction machine (IM)
A type of electrical machines that operates based on the principle of induction. While stator is formed by a multiphase AC winding, the rotor houses is (a) a series of short-circuited bars in the form of a squirrel cage or (b) a multiphase AC winding. The latter rotor form will allow for external injection of the current. In this family of electric machines, speed of the rotor is not an integer multiple of the stator frequency, and as such, they are named asynchronous machines.
Interior permanent magnet (IPM)
A type of PMSM where, unlike SM-PMSM, permanent magnets are mounted such that a magnetic saliency is established.
Permanent magnet material
Permanent magnet used in PMSM is a piece of magnetic material which, once magnetized or “charged” by an external magnetic field, retains a usefully large magnetic moment after the magnetizing force is removed. Thus, a permanent magnet becomes a source of magnetic field in the rotor.
Permanent magnet synchronous machine (PMSM)
PMSM is an electromechanical energy conversion device that forms as an important category of electric machines. This machine comprises an AC stator and a brushless rotor that houses permanent magnet. Since the frequency of the excitation in the stator winding is proportional to the mechanical speed of the rotor, this family of machines is called “synchronous.” PMSM is being considered for variety of applications including electric propulsion of modern vehicles.
Surface-mounted PMSM (SM-PMSM)
A type of PMSM where permanent magnets are placed on the surface of the rotor, making it easy to build, and skewed poles are easily magnetized on this surface-mounted type to minimize cogging torque.
A. H. Ranjbar, Babak Fahimi

Vehicle Traction Motors

Without Abstract
C. C. Chan, Ming Cheng

Switched Reluctance Motor Drives for Propulsion and Regenerative Braking in EV and HEV

Drive cycle
A profile of vehicle speed versus time
Extended constant power range
Operation of the electric motor beyond its rated speed by attempting to keep its power constant
Power electronic converter
The electronic circuit for controlling voltages and currents for power control
Regenerative braking
The use of electric machine as generator for vehicle braking force
Switched reluctance motor
A form of variable reluctance motor with discrete air gap magnetic fluxes and currents
X factor
The ratio of maximum to rated motor speeds
Mehrdad Ehsani


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