Electric Vehicles Charge Forward

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24 IEEE power & energy magazine november/december 20041540-7977/04/$20.00©2004 IEEE
by C.C. Chan and Y.S. Wong
I
november/december 2004 IEEE power & energy magazine 25
IN A WORLD WHERE ENVIRONMENT PROTECTION AND ENERGY CONSERVATION
are growing concerns, the development of EV/HEVs has taken on an accelerated pace. The
dream of having commercially viable electric/hybrid vehicles is becoming a reality. EV/HEVs
are gradually becoming available. This article reviews the status of EV/HEVs worldwide and
their state of the art, with emphasis on the engineering philosophy and key technologies. The
importance of the integration of technologies of automobile, electric motor drive, electronics,
energy storage and controls, and the importance of the integration of society strength from gov-
ernment, industry, research institutions, electric power utilities, and transportation authorities are
addressed. The challenge of EV commercialization is discussed.
The EV is a road vehicle with electric propulsion. With this broad definition in mind, EVs
may include BEVs, HEVs, and FCEVs. EV is a multidisciplinary subject involving broad and
complex aspects. However, it has core technologies: chassis and body technology, propulsion
technology, and energy source technology.
Currently, BEVs, HEVs, and FCEVs are in different stages of development, facing different
challenges, and requiring different strategies. To assist the reader, the features and issues of these
vehicles are presented in Table 1. It can be seen that the BEV critical issue is the battery, making
it mainly suitable for small, short-range, low-speed community transportation, requiring smaller
battery sizes. HEVs can meet consumer needs and has added value, but its cost is the major issue.
FCEVs have long-term potential for future mainstream vehicles; however, the technology is still
in development stage, and the cost and refueling system are the major concerns.
Why EVs?
In the next 50 years, global population will increase from 6 to 10 billion, and the number of vehi-
cles in operation will increase from 700 million to 2.5 billion. If internal combustion engines pro-
pel all these vehicles,
where will the oil come
from? And where
should the emissions be
disseminated? The
gloomy answers to
these questions compel
us to strive for sustain-
able road transporta-
tion. EVs address these
issues positively.
Concerning the environment issues, EVs can provide low emission urban transportation. Even
taking into account the emissions from the power plants needed to fuel the vehicles, the use of
EVs will still significantly reduce global air pollution. From the energy aspect, EVs offer a
secure, comprehensive, and balanced energy option that is efficient and environmentally friendly. 
Present Status
After many years in development, EV technologies are maturing. Many advanced technologies
are employed to extend driving range and reduce cost. For example, there is the use of advanced
induction motor drives and permanent-magnet brushless motor drives to improve the electric
propulsion system, the employment of advanced VRLA battery, NiMH battery, Li-ion battery,
the lithium-polymer battery, fuel cells and ultracapacitors to improve the EV energy source,
application of light body technology with light but rigid material, low drag coefficient body to
reduce the aerodynamic resistance, and low rolling resistance tires to reduce running resistance
at low and medium driving speed, as well as the adoption of advanced charging, power steering,
or variable temperature seats to enhance the EV auxiliaries. 
The U2001 is an EV developed by the University of Hong Kong (Figure 1). This four-
seat electric car is powered by a 45-kW motor and a 264 V battery pack. The specially
designed EV motor offers high efficiencies over a wide operating range, and the vehicle
What Strategies Are Needed to 
Meet Research, Development, 
and Commercialization
Challenges
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incorporates a number of advanced technologies, such as
thermoelectric variable temperature seats to minimize the
energy required for air conditioning, a navigation system to
facilitate safe and user-friendly driving, and an intelligent
energy management system to optimize energy flow. It is
essentially an ECarLab serving as a moving laboratory. Its
powertrain architecture, types of motor, and battery can be
changed as experimentation continues. The objectives of
this ECarLab are: 1) to benchmark the energy consump-
tion, emissions, and driveability; 2) to research propulsion
systems, control strategies, and energy storage systems; 3)
to use as a platform for the development and demonstration
of new technologies; and 4) to assess possible market
applications.
The world’s first mass-produced HEV product was the
Toyota Prius (Figure 2), which obtains motive power from
both a four-cylinder, ICE and a permanent-magnet, brushless
motor. A planetary gear acts as a power split device that
sends the ICE power to the wheels, as well as to a generator.
The generated electrical energy could supply the electric
motor or be stored in the 28-module, 21 kW, batteries. The
Prius offers acceleration from zero to 100 km/h in 11 s (60
m/h in 10.5 s), and a fuel economy of 23 km/l (55 m/g) for
combined city and highway operation. Both its fuel econo-
my and exhaust emissions are superior to that of any conven-
tional vehicle.
Electric and hybrid vehicles have distinct advantages in
military applications, as they are quiet, provide excellent
dynamic performance, can be designed as four wheel drives,
and cannot be detected by enemy heat sensor detection. 
Engineering Philosophy 
of EV Development
The EV engineering philosophy is essentially the integration
of automotive and electrical engineering. System integration
and optimization are prime considerations for achieving good
EV performance at an affordable cost. Since the characteris-
tics of electric propulsion are fundamentally different from
those of engine propulsion, a novel design approach is essen-
tial for EV engineering. Moreover, advanced energy sources
and intelligent energy management are key factors to enable
EVs to compete with ICEVs. Of course, overall cost effective-
ness is the fundamental factor for the marketability of EVs.
The design approach of modern EVs should include state-
of-the-art technologies from automobile engineering, electri-
cal and electronic engineering, and chemical engineering,
should adopt unique designs particularly suitable for EVs,
and should develop special manufacturing techniques particu-
larly suitable for EVs. Every effort should be made to opti-
mize energy use. 
Of importance is the understanding of the torque-speed
requirement of EVs at different driving profiles. Urban and
highway driving schedules dictate different parameters. Hence,
for urban driving, the powertrain operates in a low-speed, high-
torque profile, while for highway driving, the opposite is true. 
26 IEEE power & energy magazine november/december 2004
Acronyms
AFC Alkaline fuel cell
BEV Battery electric vehicle
DMFC Direct methanol fuel cell
EV Electric vehicle
FCEV Fuel cell electric vehicle
HEV Hybrid electric vehicle
ICE Internal combustion engine
ICEV Internal combustion engine vehicle
Li-ion Lithium-ion
MCFC Molten carbonate fuel cell
NiMH Nickel-metal hydride
PAFC Phosphoric acid fuel cell
PEM Proton exchange membrane
PHEV Plug-in hybrid electric vehicle
PM Permanent magnet
SOFC Solid oxide fuel cell
SPFC Solid polymer fuel cell
SR Switched reluctance
USABC United States Advanced 
Battery Consortium
VRLA Valve-regulated lead-acid
figure 1. University of Hong Kong U2001.
figure 2. Toyota Prius (Source: Dave Hermance: New effi-
ciency baseline 2004 Toyota Prius. EPRI Hybrid Electric
Vehicle Working Group, Nov. 15, 2003).There are a number of
design and safety issues
that are distinctive to elec-
tric vehicles, both because
of the necessity of con-
serving battery energy for
propelling the vehicle and
because of its special
characteristics. These
include provision of heat-
ing and air-conditioning
subsystems, maintenance
of the auxiliary power
subsystems, special
requirements for the brak-
ing, suspension, and
wheel systems, and the
safety of batteries, con-
nectors, and other electri-
cal systems in the vehicle.
EV and HEV
Configurations 
EV Configurations
Compared with the ICEV,
the configuration of the
EV is rather flexible. This flexibility is due to several unique
factors. EV energy flow is basically in flexible electrical
wires rather than rigid mechanical links. Thus, the concept
of distributed subsystems in the EV is really achievable.
Also, different EV propulsion arrangements involve a signif-
icant difference in the system configuration, and different
EV energy sources (such as batteries and fuel cells) have dif-
ferent characteristics and different refueling systems.
Figure 3 shows the composition of the EV, consisting of
three major subsystems: electric propulsion, energy source,
and auxiliary. The electric propulsion subsystem comprises
the electronic controller, power converter, electric motor,
mechanical transmission, and driving wheels. The energy
source subsystem involves the energy source, energy man-
agement unit, and energy refueling unit. The auxiliary sub-
system consists of the power steering unit, temperature
november/december 2004 IEEE power & energy magazine 27
Electronic
Controller
Power
Converter
Electric
Motor
Wheel
Mechanical
Transmission
Wheel
Power
Steering
Unit
Auxiliary
Power
Supply
Temperature 
Control
Unit
Energy
Source
Energy
Refueling
Unit
Energy
Management
Unit
Energy Source
Subsystem Auxiliary Subsystem
Steering
Wheel
Electric Propulsion Subsystem
Brake
Accelerator
Energy
Source
figure 3. EV composition.
table 1. Characteristics of BEV, HEV, and FCEV.
Types of EVs Battery EVs Hybrid EVs Fuel Cell EVs
Propulsion • electric motor drives • electric motor drives • electric motor drives
• Internal combustion engines
Energy system • battery • battery • fuel cells
• ultracapacitor • ultracapacitor
• ICE generating unit
Energy source and • electric grid charging facilities • gasoline stations • hydrogen
infrastructure • electric grid charging facilities • methanol or gasoline
(optional) • ethanol
Characteristics • zero emission • very low emission • zero emission or ultra low 
• independence on crude oils • long driving range emission
• 100–200 km short range • dependence on crude oils • high energy efficiency
• high initial cost • complex • independence on crude oils
• commercially available • commercially available • satisfied driving range
• high cost now
• under development
Major issues • battery and battery management • managing multiple energy sources • fuel cell cost
• high performance propulsion • dependent on driving cycle • fuel processor
• charging facilities • battery sizing and management • fueling system
control unit, and auxiliary power supply. In the figure, a
mechanical link is represented by a double line, an electrical
link by a thick line, and a control link by a thin line. The
arrow on each line denotes the direction of electrical power
flow or control information communication. Based on the
control inputs from the brake and accel-
erator pedals, the electronic controller
provides proper control signals to
switch the power devices of the power
converter which functions to regulate
power flow between the electric motor
and energy source. The backward
power flow is due to regenerative brak-
ing of the EV, and this regenerative
energy can be stored provided that the
energy source is receptive. Notice that
most available EV batteries (except
some metal/air batteries), as well as
capacitors and flywheels, readily accept
regenerative energy. The energy man-
agement unit cooperates with the elec-
tronic controller to control regenerative
braking and hence to optimize the sys-
tem energy flow. It also works with the
energy refueling unit to control refuel-
ing and to monitor usability of the ener-
gy source. The auxiliary power supply
provides the necessary power with dif-
ferent voltage levels for all auxiliaries,
especially the temperature control and
power steering units. 
HEV Configurations
The major challenges for HEV design are managing multi-
ple energy sources highly dependent on driving cycles, bat-
tery sizing, and battery management. HEVs take advantage
of the electric drive to compensate for the inherent weak-
nesses of the ICE. They avoid idling, increase ICE efficien-
cy and reduce emission during
starting, low-speed operation, and
high-speed operation, and use
regenerative braking instead of
mechanical braking during decel-
eration and downhill driving. 
The HEV meets customer
needs and has added value, but
cost is the major drawback. But,
with government incentives to
reduce the initial cost burden, the
HEV may reach a substantial
share in mainstream automobile
production.
Traditionally, HEVs were
classified into two categories:
series and parallel. Recently, with
the introduction of some HEVs
offering the features of both the
series and parallel hybrids, the
classification has been extended
to three categories: series, paral-
28 IEEE power & energy magazine november/december 2004
figure 4. Classification of HEVs.
F E
G
B P M
T
F E
G
B P M
T
F E
P M/G
B P M
T
B P M
T
EF
Series Hybrid Parallel Hybrid
(a)
(c)
(b)
(d)
Series-Parallel Hybrid Complex Hybrid
B: Battery
E: ICE
F: Fuel Tank
G: Generator
M: Motor
P: Power Converter
T: Transmission (Including Brakes, Clutches, and Gears)
Electrical Link
Hydraulic Link
Mechanical Link
table 2. Key parameters of EV batteries.
Specific Energy Specific Cycle Projected 
Energy a Density a Power b Life b Cost d
(Wh/kg) (Wh/l) (W/kg) (cycles) (US$/kWh)
VRLA 30–45 60–90 200–300 400–600 150
Ni-Cd 40–60 80–110 150–350 600–1200 300
Ni-Zn 60–65 120–130 150–300 300 100–300
Ni-MH 60–70 130–170 150–300 600–1200 200–350
Zn/Air 230 269 105 NA c 90–120
Al/Air 190–250 190–200 7–16 NA c NA
Na/S 100 150 200 800 250–450
Na/NiCl2 110 149 150 1000 230–350
Li-Polymer 155 220 315 600 NA
Li-ion 90–130 140–200 250–450 800–1200 >200
USABC 200 300 400 1000 <100
NA: not available.
a at C/3 rate.
b at 80% DOD.
c mechanical recharging.
d for reference only.
november/december 2004 IEEE power & energy magazine
lel, and series-parallel. However, some recent HEVs cannot
be classified into any of the existing categories, which
required the addition of a fourth. As a result, HEVs are
now classified as
✔ series hybrid
✔ parallel hybrid
✔ series-parallel hybrid
✔ complex hybrid.
Figure 4 shows the functional block diagrams for each cate-
gory. The electrical link is bidirectional, the hydraulic link
is unidirectional, and the mechanical link (including the
clutches and gears) is also bidirectional. The key feature of
the series hybrid is to couple the electric power from the
ICE/generator and the battery to supply the electric power
to propel the wheels, while the key feature of the parallel
hybrid is to couple the mechanical power from the ICE and
the electric motor to propel the wheels. The series-parallel
hybrid is a direct combination of both the series and parallel
hybrids, whereas the complex hybrid offers additional and
versatile operating modes.
Due to the variations in HEV configurations, different
power control strategies are necessary to regulate the power
29
figure 5. EV propulsion system overview.
Electronic ControllerPower Converter Transmission
and Differential
Software
VVVF
FOC
MRAC
STC
VSC
NNC
Fuzzy
Hardware Devices
µ Processor
µ Controller
DSP
Transputer
GTO
BJT
MOSFET
IGBT
MCT
Topology
Chopper
Inverter
PWM
Resonant
CAD
FEM
EM
Force
Thermal
Graphics
DC
IM
SRM
PMSM
PMBM
PMHM
VVVF — Variable Voltage
 Variable Frequency
FOC — Field Oriented
 Control (Vector Control)
MARC — Model Reference
 Adaptive Control
STC — Self-Tuning Control
VSC — Variable Structure
 Control
NNC — Neural Network
 Control
Fuzzy — Fuzzy Control
DSP — Digital Signal
 Processor
GTO — Gate Turn-Off
 Thyristor
BJT — Bipolar-Junction
 Transistor
MOSFET — Metal-Oxide
 Field-Effect Transistor
IGBT — Insulated-Gate
 Bipolar Transistor
MCT — MOS-Controlled
 Thyristor
PWM — Pulse-Width
 Modulation 
CAD — Computer-Aided
 Design
FEM — Finite Element
 Method
EM — Electromagnetic
DC — Direct Current Motor
IM — Induction Motor
SRM — Switched
 Reluctance Motor
PMSM — Permanent Magnet
 Synchronous Motor
PMBM — Permanent Magnet
 Brushless Motor
PMHM — Permanent Magnet
 Hybrid Motor
Type
Batteries
Electric Motor
IEEE power & energy magazine november/december 2004
table 3. Specifics of batteries.
Lithium-Ion
Advantages of Nickel Cadmium Nickel Metal 
on Lead Acid (NiCd) Hydride (NiMH) Conventional Polymer
Lead acid • gravimetric • gravimetric • gravimetric • gravimetric
energy density energy density energy density energy density
• volumetric • volumetric • volumetric • volumetric 
energy density energy density energy density energy density
• operating • self discharge • voltage output • self discharge
temperature range rate • self discharge rate
• self discharge rate rate • design
• reliability characteristics
(progressive 
extinction)
Nickel cadmium • higher • gravimetric • gravimetric • gravimetric 
(NiCd) cyclability energy density energy density energy density
• voltage • volumetric • volumetric • volumetric 
output energy density energy density energy density
• price • voltage output • self discharge
• self discharge rate
rate • design
characteristics
Nickel metal • higher • operating • gravimetric • gravimetric 
hydride (NiMH) cyclability temperature energy density energy density
• voltage range • volumetric • volumetric
output • higher energy density energy density
• price cyclability • operating • operating 
• self discharge rate temperature temperature 
• price range range
• higher cyclability • self discharge
• voltage output rate
• self discharge • design
rate characteristics
Lithium-ion
conventional • higher • operating • price • gravimetric
cyclability temperature range • safety energy density
• price • higher • discharge rate • volumetric 
• safety cyclability • recyclability energy density 
• recyclability • price (potential)
• safety • design 
• recyclability characteristics
• safety
• price
polymer • higher • operating • volumetric • operating
cyclability temperature range energy density temperature 
• price • higher cyclability • higher cyclability range
• price • price • higher cyclability
Absolute • higher • operating • volumetric • gravimetric • gravimetric
advantages cyclability temperature range energy density energy density energy density
• price • price • volumetric • volumetric
energy density energy density
• self discharge (potential)
rate • self discharge
• voltage output rate
• voltage output
• design
characteristics
(Source: C Pillot, “The worldwide rechargeable battery market 2003–2008,” 
in Proc. Sixth China Int. Battery Fair, Beijing, China, Apr. 2004).
30
november/december 2004 IEEE power & energy magazine 31
EV is a multidisciplinary subject involving broad and complex
aspects. However, it has core technologies: chassis and body
technology, propulsion technology, and energy source technology.
flow to or from different components. These control strate-
gies aim to satisfy a number of goals for HEVs. The four key
goals are:
✔ maximum fuel economy
✔ minimum emissions
✔ minimum system costs
✔ good driving performance.
In HEVs, it is essential to have multienergy powertrain con-
trol with an effective control algorithm. The control system is
implemented through a controller area network bus to reduce
wires while increasing reliability. It should be noted that the
control algorithm should take into account real world driving
cycles, not just the standard cycles, and also consider the driv-
er’ behavior, which affects energy consumption and emission.
PHEVs use electricity when the battery is highly charged
and then switch to hybrid mode when the battery charge is
low or for greater vehicle speeds, which require full power.
They offer the following benefits as compared with conven-
tional engine dominant hybrid vehicles:
✔ less maintenance
✔ better gas mileage
✔ reduction in air pollution and subsequent greenhouse
gas (CO2) emission and petroleum use
✔ less noise and vibration
✔ improved acceleration
✔ the ability to operate various appliances with the engine off.
Electric Propulsion
The electric propulsion system is the heart of the EV. It con-
sists of the motor drive, transmission (sometimes optional),
and wheels. The motor drive comprising the electric motor,
power converter, and electronic controller is the core of the
EV propulsion system. The major requirements of the EV
motor drive are
✔ high instant power and high power density
✔ high torque at low speeds for starting and climbing, as
well as high power at high speed for cruising
✔ very wide speed range including constant-torque and
constant-power regions
✔ fast torque response
✔ high efficiency over wide speed and torque ranges
✔ high efficiency for regenerative braking
✔ high reliability and robustness for various operating
conditions
✔ reasonable cost.
The choice of electric propulsion systems for EVs mainly
depends on three factors: driver expectation, vehicle con-
straint, and energy source. Driver expectation is defined by a
driving profile that includes acceleration, maximum speed,
climbing capability, braking, and range. The vehicle con-
straint depends on the vehicle type, weight, and payload. The
energy source relates to the batteries, fuel cells, capacitors,
flywheels, and various hybrid sources. Thus, the process of
identifying the preferred features and packaging options for
electric propulsion has to be carried out at the system level.
The interactions between subsystems and the likely effects of
system tradeoffs must be examined.
The development of electric propulsion systems has been
based on the growth of technologies, especially electric
motors, power electronics, microelectronics, and control
strategies. Figure 5 shows an EV propulsion system
overview, including the possible types of motors, computer
aided design methodology, power converter devices/topolo-
gy, control hardware, software, and strategy. Today, as a
result of motor technology, CAD FEM analyzed induction
motors and PM brushless motors are favored. In power con-
verter technology, PWM/IGBT inverters are most popular.
With regard to control technology, microprocessor or DSP
based vector controls are very common. 
Traditionally, dc motors have been prominent in electric
propulsion because their torque-speed characteristics well
suit traction requirement and their speed controls are simple.
However, the dc motor has a commutator that requires regu-
lar maintenance. Recent technological developments have
moved commutatorless motors to assume the advantages of
higher efficiency, higher power density, lower operating cost,
more reliability, and maintenance-freedom over dc motors.
As high reliability and maintenance-free operation are prime
considerations for electric propulsion in EVs, commutatorless
motorsare becoming attractive. PM brushless motors are also
promising because they produce a magnetic field with higher
efficiency and higher power density. SR motors also have
potential because of simple and robust construction.
Energy Sources
Batteries
The working conditions of batteries in the various EV
applications are quite different. Therefore, the performance
requirements of EV batteries should be fully understood.
32 IEEE power & energy magazine november/december 2004
Table 2 indicates the key parameters of EV batteries as
compared with the goal figures by the USABC. Table 3
shows the specific advantages and comparison of various
EV batteries. Table 4 compares EV batteries at “deep
cycle” condition. 
Fuel Cells
The fuel cell is an electrochemical device that converts the
free-energy change of an electro-
chemical reaction into electrical
energy. In contrast to a battery, the
fuel cell generates, rather than
stores, electrical energy and contin-
ues to do so as long as fuel supply
is maintained. Its advantages are
efficient conversion of fuel to elec-
trical energy, quiet operation, zero
or very low emissions, waste heat
recoverability, rapid refueling, fuel
flexibility, durability, and reliability.
Hydrogen seems to be an ideal
nonpolluting fuel for the fuel cell
because it has the highest energy
content per unit of weight of any
fuel, and the by-product as a result
of the fuel cell reaction is just
plain water.
Typical characteristics of fuel
cells are summarized in Table 5. It
can be seen that both the MCFC
and SOFC suffer from very high-
temperature operation, respectively
over 600 ◦C and 900 ◦C, making
them difficult for EV application.
Though 30 years old the DMFC is
still under development and the
available power level and are too
low for practical application to
EVs. The others, PAFC, AFC, and
SPFC, also known as PEM fuel
cell, are all technically possible for
EV applications. A representative
FCEV configuration is shown in
Figure 6.
EV Commercialization
The hurdles and barriers facing EV
commercialization are listed in
Table 6. Key issues for successfully
commercializing and promoting
EVs lie in the production of low-
cost, good performance products,
the leveraging of initial investment,
and the ability to provide an effi-
cient infrastructure. The overall
strategy must take into account how to fully utilize the com-
petitive edge, share the market and resources, and produce
EVs that can meet the market demand. 
The key to success lies in two integrations. The first is
the integration of society strength, including government
support, financing and venture capital, incentives for indus-
try, and technical support from academic institutions. The
second is the integration of technical strength, which is the
table 5. Typical characteristics of fuel cells.
PAFC AFC MCFC SOFC SPFC DMFC
Working temp. 150–210 60–100 600–700 900–1000 50–100 50–100
(◦C)
Power density 0.2–0.25 0.2–0.3 0.1–0.2 0.24–0.3 0.35–0.6 0.04–0.23
(W/cm2)
Projected life 40 10 40 40 40 10
(kh)
Projected cost 1000 200 1000 1500 200 200
(US$/kW)
PAFC—phosphoric acid fuel cell.
AFC—alkaline fuel cell.
MCFC—molten carbonate fuel cell.
SOFC—solid oxide fuel cell.
SPFC—solid polymer fuel cell also known as proton exchange membrane fuel cell.
DMFC—direct methanol fuel cell.
table 6. Hurdles and barriers for the application
of alternative propulsion systems.
Battery electric vehicle Weight, durability, range , cost, recycling, size,
recharge time
Hybrid Battery, durability, size, weight, cost
Mid hybrid/ISG Cost, weight, reliability
42 V board net voltage Safety, cost
Fuel cell (hydrogen on board) Infrastructure, cost, hydrogen production, storage, 
reliability, durability, customer acceptance of 
hydrogen
Fuel cell (reformer) Warm up time, efficiency, emissions, CO poisoning, 
transient operation
Auxiliary Power Unit Size, weight, safety, durability, reliability, cost, 
efficiency, cooling
Storage for mechanical energy Flywheel, safety, weight, hydraulic, noise, cost
table 4. Comparison of EV batteries at “Deep Cycle” condition.
High Energy Design in Deep Nickel Metal
Cycle Application Lead Acid Hydride Lithium-Ion
Energy density (Wh/kg) 35 55 >80
Power density (W/kg) 150 230 1,000
Charge acceptance (W/kg) 50 200 600
Life time (number at 80% swing 125 3,000 2,500
of cycles) at 5% swing 50,000 300,000 140,000
Cost level USD/kWh 150 450 500
(Source: C. Rosenkranz, “Deep cycle batteries for plug-in hybrid application,” EPRI
hybrid electric vehicle working group, Nov.15, 2003).
november/december 2004 IEEE power & energy magazine
effective integration of the state-of-the-art technologies of
automobile, electrical, electronic, chemical, and material
engineering.
At first, EVs will not compete with
ICEVs in every application. Therefore,
it is important to identify feasible niche
markets, namely the BEV for commu-
nity transportation and the HEV for
wider applications. This will enable the
identification of required technical
specifications and allow for the cre-
ation of system integration and opti-
mization. In order to achieve cost
effectiveness, a unique design approach
and a unique manufacturing process
should be developed. Excellent after-
sales service and effective infrastruc-
ture are also essential. Also, convenient
charging stations, now in pilot opera-
tion in Japan, may well be the forerun-
ner to overcome the present
short-range disadvantage of BEVs.
Conclusion
Environment protection and energy conservation have
pushed the development of the EV. Looking ahead into the
next few decades, the advent of new technologies will
surely make the EV a stark reality. BEV will be designed
for the small vehicle market. HEV will meet consumer
needs and grow at a fast rate, though its key issue remains
the optimization of multiple energy sources to obtain best
performance at lowest cost. FCEV will have long-term
potential to be the mainstream vehicle of the future
because of almost nonexistent emission and a driving
range comparable to an ICEV. The major challenge of
FCEV is the development of a low cost fuel cell and an
efficient fuel processor and refueling system. A well
thought-out engineering philosophy is essential for the
strategic development of electric vehicles.
For Further Reading 
C.C. Chan and K.T. Chau, Modern Electric Vehicle Technol-
ogy. Oxford, UK: Oxford Univ. Press, 2001.
C.C. Chan, “The state of the art of electric and hybrid
vehicles,” Proc. IEEE, vol. 90, no. 2, pp. 247–275, Feb. 2002.
M.H. Westbrook, The Electric Car. London: IEE, 2001.
J.M. Miller, Propulsion Systems for Hybrid Vehicles. Lon-
don: IEE 2004.
Biographies
C.C. Chan is an IEEE Fellow and a Fellow of the Royal Acad-
emy of Engineering, U.K., the Chinese Academy of Engineer-
ing, The Ukraine Academy of Engineering Sciences, IEE and
HKIE. He has had 11 years industrial experience and 29 years
academic experience. He is currently the honorary professor
and the former head of the Department of Electrical and Elec-
tronic Engineering, University of Hong Kong. He is the found-
ing president of the International Academy for Advanced
Study, China, cofounder and president of the World Electric
Vehicle Association, and president of the Asian Electric Vehicle
Society. He received the IEE International Lecture Medal in
2000 and delivered lectures on electric vehicles worldwide.
Y. S. Wong is an IEEE member and a Ph.D. student at
the Department of Electrical and Electronic Engineering,
University of Hong Kong. His main research areas are in
electric vehicles.
33
The electric propulsion system is the heart of the EV. 
It consists of motor drive, transmission and controller, plus the
integration with engine power train in the case of the HEV.
Figure 6. FCEV configuration.
Hydrogen TankFuel-Cell Assembly
p&e