Copyright © 2018 Authors. This is an open access article distributed under the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. International Journal of Engineering & Technology, 7 (4.35) (2018) 482-486 International Journal of Engineering & Technology Website: www.sciencepubco.com/index.php/IJET Research paper Charging and Discharging Control of Li-Ion Battery Energy Management for Electric Vehicle Application M. Verasamy 1 , M. Faisal 2* , Pin Jern Ker 3 , M A Hannan 4 , 1 Department of Electrical Power Engineering, College of Engineering, University Tenaga Nasional, 43000, Kajang, Malaysia 2 International Islamic University Chittagong, Bangladesh *Corresponding author E-mail: M. Faisal (fsl3319@gmail.com) Abstract Electric vehicle (EV) is now replacing the conventional fuel driven vehicle as it has strong contribution to face the challenges of global warming issues. This system has the energy storage device which can be introduced by lithium-ion (li-ion) battery banks. Lith- ium-ion is mostly popular because of its high capacity and efficiency. Nevertheless, li-ion battery needs protective mechanism to control overcharged or undercharged of the cell that can reduce the life expectancy and efficiency. Hence, a control model needs to develop to enhance the protection of battery. Therefore, the key issue of the research is to investigate the performance of Li-ion bat- tery energy management system (BMS) for electrical vehicle applications by monitoring and balancing the cell voltage level of bat- tery banks using Simulink software. A bidirectional flyback DC-DC converter is investigated in the BMS model to control the under- charging or overcharging of cells. An intelligent charge control algorithm is used for this purpose. Backtracking search optimization algorithm (BSA) is implemented to optimize the parameters for generating regulated PWM signal. Obtained results were observed within the safety operating range of Li-ion battery (3.73 V – 3.87V). Keywords: Battery energy management; Charge equalization; Electric Vehicle; Protection; Optimization. 1. Introduction The recent trends of the modern economic development of the automobile and renewable resources are looking forward to solve the global environmental issues. Conventional internal combustion engine (ICE) based vehicles use fossil fuel to drive the vehicle. During combustion, these vehicles dissipate about 85% of total energy as heat [1] that causes the emission of toxic carbon monox- ide, nitrogen oxides, carbon dioxide (CO 2 ) and other greenhouse gases (GHGs) [2]. Moreover, human practices and behavior are another significant factor for environmental damages. Different researches on environmental issues are proposing to control public practices and behavior to reduce the negative impact on environ- ment. Besides this, shortage of reserved fuel urges automotive industry to search for ecofriendly energy source. Malaysian Government has taken the step to lessen 40% GHG emission by the year 2020 by introducing electric vehicle (EV) and hybrid electric vehicle (HEV). As EV is a clean vehicle with a greater efficiency and pollution free, it can be defined as ‘zero emission vehicle'. EV operation depends on the energy storage system from which energy is transferred to the motor to drive the vehicle [3]. EV system comprises of the renewable sources and has remarkable properties to yield the wastage energies from re- generative braking, engine vibration and heat. Moreover, vehicle to grid (V2G) technology facilitates the EV to boost the stability of network by supplying surplus energy to the electricity grid when the power demand reaches the peak. An electric vehicle is generally comprises of a module charger, electric motor, controller, regenerative braking system, battery pack module and BMS. Storage system requires protective equip- ment to safe the batteries from damages [4]. Thus, the choice of energy storage, resources and storage management system are vital for modern EV technologies. Although lead-acid is the wide- ly used storage system in the world, lithium-ion battery is gaining more popularity due to its efficient charging and discharging char- acteristics with improved life cycle. Previous researches on BMS focused on increasing the life expec- tancy, safety and efficiency of the battery. As the cell of battery pack undergo multiple times of charge-discharge cycles, they may suffer from overcharge or undercharge problems. The under- charged cell is responsible to reduce the efficiency while over- charged cells can sabotage the storage. Therefore, charge equaliza- tion among the cells is vital to increase the battery performance and safety [5]. The proposed algorithm contributes to the equalization technique till all the cells getting equalized accordingly. It allows the under- charged cell to get charged from the battery pack or it supplies surplus energy from the overcharged cell to the battery bank. Hence, the developed mechanism can guard the cell from getting damaged. This study proposes to develop the BMS with an intelligent charge control technique to investigate the optimum charging and dis- charging characteristics of storage system. The rest of the paper is organized as follows. In section II, concerning issues of BMS in vehicle application is discussed. Intelligent charge equalization technique is described in section III. Section IV discusses about the simulation model and detailed analysis of charging and dis- charging characteristics of the proposed model. Finally, conclu- sions are drawn in section V.