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01-04 

1 

 

 

 

Perspective 

Electric vehicles’ powertrain systems architectures 

design complexity 
Isa Banagar, Amin Mahmoudzadeh Andwari*, Sadegh Mehranfar, Juho Könnö, Emil Kurvinen 

Machine and Vehicle Design (MVD), Materials and Mechanical Engineering, University of Oulu, P.O. Box 4200, FI-
90014 Oulu, Finland 

A R T I C L E   I N F O 
 

Article history: 
Received 01 December 2022  
Received in revised form 
30 December 2022 
Accepted 03 January 2023 
 
Keywords:  
Hybrid electric vehicle, Battery electric vehicle, 
Powertrain system, Power management 
 
*Corresponding author 
Email address:  
amin.mahmoudzadehandwari@oulu.fi 
 
 
DOI: 10.55670/fpll.futech.2.3.1 
 

A B S T R A C T 
 

Strict emission regulations and energy scarcity have ushered in a new era of 
automotive technology. Utilizing electric power as a second source of energy or 
an alternative to fossil fuel energy has been the center of attention for decades. 
Implementing electric energy in vehicles’ powertrain systems requires new 
system architecture and rigorous methods for decision-making in a multi-
disciplinary design procedure. Accordingly, the challenge is to define the design 
requirements and the economic feasibility of the final product. 
 

 

1. Introduction 

The term "electrified vehicles" (EVs) refers to a broad 
category of vehicles utilizing electrical power in their 
powertrain system. The share of electric power utilized in the 
powertrain system and the powertrain system's architecture 
are the two basic methods for the classification of electrified 
vehicles. Simple technologies like start/stop or regenerative 
braking systems or even more complex technologies like 
battery packs, fuel cells, and E-Motor can be implemented to 
integrate electrical power into the powertrain system. 
Therefore, an electrified vehicle can be categorized as a 
micro-hybrid, mild-hybrid, full hybrid, and battery electric 
vehicle (BEV) depending on the percentage of electric power 
and technology level, which is more likely consumer-oriented 
[1]. Micro hybrid vehicles utilize 5-10 % electric power in 
their powertrain by implementing technologies such as 
internal combustion engine (ICE) start/stop. Therefore, they 
do not use electric power to generate traction, it is utilized to 
assist the powertrain by optimizing the running time of the 
ICE [2]. The share of electric power increases up to 25 % in a 
mild hybrid vehicle by implementing an E-Motor to assist the 
ICE for traction generation. Mild hybrid vehicles cannot run 
only on electric power, so the E-Motor contributes to traction 
generation and has responsibility for energy harvesting as a 
regenerative brake. Full hybrid vehicles implement up to 80 
% electric power for traction generation and can be run on 
either electric mode or ICE mode or on both modes (i.e., 

hybrid mode). The different architectures of full hybrid 
vehicles, which are discussed in the next section, increase the 
overall efficiency of the powertrain by providing different 
combinations of electrical and mechanical power for traction 
generation. The last one is BEVs, which utilize electricity as 
the only energy source for traction generation. Although the 
overall efficiency of the BEV’s powertrain is much higher than 
conventional ICE, specific component arrangements in its 
powertrain are required for optimum performance. These 
configurations are discussed in the next section. 

2. EV's Powertrain Systems Architectures 

The architecture of the energy flow from energy storage 
to the traction force at the wheels can be used to classify a full 
hybrid electrified vehicle. In general, hybrid electric vehicles 
(HEV), by having two propulsion systems and energy storage 
systems, can be classified as parallel, series, and parallel-
series (power-split) hybrids depending on how the two 
systems are configured. In parallel architecture, ICE’s and E-
Motor’s output shafts are connected to the wheels through a 
transmission system, so each of them can be utilized 
separately and simultaneously for traction generation. The 
powertrain architecture of a mild hybrid vehicle is quite 
similar to a full hybrid parallel architecture, but electric 
power cannot be considered the sole power source for 
traction generation in a mild hybrid in contrast with a full 
hybrid parallel architecture. In a series-hybrid setup, the ICE 

 

 

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I. Banagar et al. /Future Technology                                                                                         August 2023| Volume 02 | Issue 03 | Pages 01-04 

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is only connected to a generator to charge the battery pack, 
limiting the use of the ICE's power to just generate electricity 
and dedicating the E-Motor power for traction generation. 
The electrical part of the series hybrid powertrain is quite the 
same as BEVs from the technological point of view but may 
differ from each other in terms of sizing, considering the 
amount of required output traction and charging method. In 
parallel-series design (i.e., power-split), by implementing a 
specific coupling mechanism, the ability to charge the battery 
pack with ICE (e.g., the same charging method in series 
hybrid) is added to the parallel design. This connection 
mechanism offers a wide range of options for regulating the 
ICE and E-Motor power so that both earlier configurations are 
possible. To increase the range of full hybrid vehicles, 
solutions such as a larger battery pack and the ability to 
charge the battery pack directly from the electricity grid have 
been devised as known Plug-in hybrid electric vehicles 
(PHEV). Plug-in charging capability is applicable to all 
aforementioned architecture of full hybrid vehicles. Different 
architectures of full hybrid electric vehicles are illustrated in 
Figure 1 [3]. PHEVs minimize vehicles’ fuel consumption and 
decrease the emission level, especially on daily trips, by 
having a larger battery pack that provides a longer all-electric 
range. A series hybrid vehicle with a large battery pack and 
plug-in charging option can be categorized as a range-
extended BEV, such as BMW i3. 

 

 

 

 

BEV’s powertrain system can come in a variety of design 
concepts. Although E-Motors typically have higher efficiency 
compared to ICEs, this advantage is greatly reduced in low-
speed and low-torque operating conditions. For this reason, 
gearbox or multi-motor designs are utilized to boost the 
powertrain's flexibility addressing BEV's major issues like 
range anxiety. Even though a multi-speed or continuous 
variable transmission (CVT) gearbox for BEVs improves the 
powertrain's efficiency in various use-case scenarios [4], a 
multi-motor arrangement can be a more practical way to 
increase the adaptability of a fully electric powertrain [5]. 
Most of the technologies implemented in EVs are mature 
enough to meet performance and efficiency targets. Despite 
all these technological breakthroughs, electrified vehicles still 
face significant barriers to market penetration, including 
range anxiety. The above-mentioned configuration's primary 
goal is to increase the powertrain's overall efficiency. 
However, it should be noted that adding additional parts 
meant the need for a more sophisticated technique of 
coupling and more effort for improving the powertrain 
component sizing and energy control strategy. The 
performance of a vehicle is greatly influenced by the proper 
selection of key powertrain parameters. It stands to reason 
that proper component size optimization will be essential to 
achieving the necessary performance, energy efficiency, and 
reasonable lifecycle cost of EVs.  

 

 

 

 

 

Hybridization Factor

Micro
5-10%

Mild
10-25%

Full Hybrid
20-80%

Parallel Series-Parallel Series BEVMicro 

C
o

n
ven

tio
n

al arch
itectu

re
O

n
ly Start/Sto

p
 Te

ch
n

o
lo

gy

BEV
100%

EM: E-Motor | Ch.: Charger | BP: Battery Pack | Gn.: Generator | Trns.: Transmission | Diff.: Differential 

Fuel 
Tank

Trns.

EM

BP
Ch.

ICE

Fuel 
Tank

Only in Plug-in
Configuration

ICE

Trns.

EM 1

EM
 2

BP
Ch

PS

Fuel 
Tank

Trns.

EM

BP
Ch

ICE

Gn.

CH.

Diff.

EM 1

BP 

Figure 1 . Share of electric power in powertrain and architecture of electrified vehicles 



I. Banagar et al. /Future Technology                                                                                         August 2023| Volume 02 | Issue 03 | Pages 01-04 

3 

 

The component sizing is influenced by not only the 
powertrain architecture of the vehicle but also a vast variety 
of other aspects, such as the anticipated driving cycle, 
operating environment, and powertrain control strategy, to 
name a few. Energy control strategies play a key role in 
electrified powertrain design. Although in the case of HEVs, 
the energy control strategy should manage two separate 
energy systems to achieve the best efficiency while 
preserving deriving performance and comfort, in the case of 
BEVs there is only one energy system, so they differ from each 
other. Despite all the advancements in the abovementioned 
technologies, technologies related to EVs have a small share 
compared to other technologies related to ICEs. For instance, 
these technologies were utilized on just 7% of vehicles in the 
United States in 2020, Figure 2 [6]. 

 

To give a thorough understanding of the final product 
characteristics, the design of EVs requires cross-domain 
engineering as well as multiscale and multiphysics 
simulation. New products are becoming more and more 
reliant on software due to the use of sophisticated simulation 
tools to create a product that complies with the specifications. 
Model-Based System Engineering (MBSE) provides a basis to 
integrate several design domains by using modeling 
approaches to logically translate needs into specifications of 
a final product. An MBSE design approach can provide a 
decision-making framework not only for EV design and 
production but also for defining the required specifications of 
each product subsystem. 

 

 Figure 2 . Manufacturer Use of Emerging Technologies for Model Year 2020 [6] 



I. Banagar et al. /Future Technology                                                                                         August 2023| Volume 02 | Issue 03 | Pages 01-04 

4 

 

3. Conclusion 

By and large, the design complexity of an electrified 
powertrain can be introduced as complexity in the control 
strategy and sizing of the components. This complexity is not 
only affected by the number and architecture of the 
powertrain’s components but also by the diversity of its 
operational conditions. The design complexity should be 
considered as a barrier to the market penetration of EVs; thus 
a holistic framework, such as MBSE, is required to have a 
compromised solution for a right-design strategy. 

Ethical issue 
The authors are aware of and comply with best practices in 
publication ethics, specifically with regard to authorship 
(avoidance of guest authorship), dual submission, 
manipulation of figures, competing interests, and compliance 
with policies on research ethics. The authors adhere to 
publication requirements that the submitted work is original 
and has not been published elsewhere. 

Data availability statement 
Data sharing is not applicable to this article as no datasets 

were generated or analyzed during the current study. 

Conflict of interest 

The authors declare no potential conflict of interest. 

References 

[1] I. Husain, Electric and Hybrid Vehicles: Design 

Fundamentals, Third Edition (3rd ed.), CRC Press, 

2021.  

[2]  Andwari, A.M.; Said, M.F.M.; Aziz, A.A.; Esfahanian, V.; 

Salavati-Zadeh, A.; Idris, M.A.; Perang, M.R.M.; Jamil, 

H.M. Design, Modeling and Simulation of a High-

Pressure Gasoline Direct Injection (GDI) Pump for 

Small Engine Applications. J. Mech. Eng. 2018, 1, 107–

120 

[3]  D. Thakur, "e-vehicleinfo.com," 13 07 2021. [Online]. 

Available: https://e-vehicleinfo.com/electric-vehicle-

architecture-ev-powertrain-components/. [Accessed 

11 11 2022]. 

[4]  I. I. e. a. Mazali, "Review of the Methods to Optimize 

Power Flow in Electric Vehicle Powertrains for 

Efficiency and Driving Performance.," Applied 

Sciences, p. 1735, 2022.  

[5]  B. Zhang, J. Zhang and T. Shen, "Optimal control design 

for comfortable-driving of hybrid electric vehicles in 

acceleration mode," Appl. Energy, p. 305, 2021.  

[6]  EPA, "United States Environmental Protection Agency," 

11 2021. [Online]. Available: 

https://nepis.epa.gov/Exe/ZyPDF.cgi?Dockey=P1013L

1O.pdf. [Accessed 11 11 2022]. 

 
 This article is an open-access article 

distributed under the terms and conditions of the Creative 

Commons Attribution (CC BY) license 

(https://creativecommons.org/licenses/by/4.0/). 


