Noshin Omar

Passive and active battery balancing comparison based on MATLAB simulation

Battery systems are affected by many factors, the most important one is the cells unbalancing. Without the balancing system, the individual cell voltages will differ over time, battery pack capacity will decrease quickly. That will result in the fail of the total battery system. Thus cell balancing acts an important role on the battery life preserving. Different cell balancing methodologies have been proposed for battery pack. This paper presents a review and comparisons between the different proposed balancing topologies for battery string based on MATLAB/Simulink® simulation. The comparison carried out according to circuit design, balancing simulation, practical implementations, application, balancing speed, complexity, cost, size, balancing system efficiency, voltage/current stress … etc.

Evaluation of performance characteristics of various lithium-ion batteries for use in BEV application

The purpose of this paper is to assess the capabilities of commercial lithium-ion batteries for use in battery electric vehicles (BEVs). The evaluation criteria are based on a newly developed experimental methodology which describes the performance characteristics of different batteries of various chemistries. This methodology primarily permits the user to obtain the most important battery characteristics for charging and discharging, internal resistance, efficiency, Peukert constant, thermal stability during charge and discharge phases.

PSO algorithm‐based optimal power flow control of fuel cell/supercapacitor and fuel cell/battery hybrid electric vehicles

Purpose – The purpose of this paper is to optimize the design and power management control fuel cell/supercapacitor and fuel cell/battery hybrid electric vehicles and to provide a comparative study between the two configurations.Design/methodology/approach – In hybrid electric vehicles (HEVs), the power flow control and the powertrain component sizing are strongly related and their design will significantly influence the vehicle performance, cost, efficiency and fuel economy. Hence, it is necessary to assess the power flow management strategy at the powertrain design stage in order to minimize component sizing, cost, and the vehicle fuel consumption for a given driving cycle. In this paper, the PSO algorithm is implemented to optimize the design and the power management control of fuel cell/supercapacitor (FC/SC) and fuel cell/battery (FC/B) HEVs for a given driving cycle. The powertrain and the proposed control strategy are designed and simulated by using MATLAB/Simulink. In addition, a comparative study...

Development of 2D Thermal Battery Model for Lithium-ion Pouch Cells

This paper represents a simulation model for a 2D-thermal model applied on a Lithium-ion pouch battery. This model is able to describe the transient response of the thermal distribution accurately. The heat generation parameters used in this model have been obtained experimentally from dedicated estimation technique. The experimental and simulation are performed at different charge and discharge current rates. The experimental results are in good agreement with the developed model. The battery thermal distributions using natural and forced convection cooling are studied.

Development of a Two-Dimensional-Thermal Model of Three Battery Chemistries

The growing need for accurate estimation of by fitting batterys thermal and electrical performances at different operating conditions is crucial in its applications especially in electrified vehicles. This paper presents an effective method for developing a thermal and electrical modeling methodology for calculation thermal behavior of a lithium-ion cell and the voltage response under a current solicitation. The model was elaborated on three pouch cells with different battery chemistries for use in electrical vehicles/hybrid electrical vehicles, namely lithium iron phosphate, lithium nickel manganese cobalt oxide, and lithium titanium oxide (LTO). The model, implemented in a MATLAB/Simulink interface, uses an equivalent circuit and heat-generation equations coupled a thermal model. The three cell chemistries have been investigated using test procedures and thermal images at room temperature. The results of this study show that a temperature distribution to be fairly uniform after a complete discharge for the three chemistries with the lowest temperature gradient found for the LTO-based cell. Finally, comparison between simulation results and measured data under dynamic profiles shows a good correspondence with the measurements of the validation tests with errors lying between ±4% and 2 °C for the electrical and thermal model, respectively.

State of charge estimation of LiFePO 4 batteries with temperature variations using neural networks

This paper presents a neural network oriented approach for online estimation of the state of charge (SOC) for lithium-ion batteries. Unlike other estimation strategies, this proposed technique requires no knowledge of any battery parameter and no mathematical model of the battery rather it takes into consideration ambient temperature variations while estimating the SOC. Experimental results highlight the high SOC accuracy of the estimation despite the effects of aging and temperature on the battery.

Batteries 2020 – Lithium - ion battery first and second life ageing, validated battery models, lifetime modelling and ageing assessment of thermal parameters

The European Project “Batteries 2020” unites nine partners jointly working on research and the development of competitive European automotive batteries. The project aims at increasing both the energy density and lifetime of large format pouch lithium-ion batteries towards the goals targeted for automotive batteries (250 Wh/kg at cell level, over 4000 cycles at 80% depth of discharge). Three parallel strategies are followed in order to achieve those targets: (i) Highly focused materials development; two improved generations of NMC cathode materials allows to improve the performance, stability and cyclability of state of the art battery cells. (ii) Better understanding of the ageing phenomena; a robust and realistic testing methodology has been developed and was carried out. Combined accelerated, real driving cycle tests, real field data, post-mortem analysis, modelling and validation with real driving profiles was used to obtain a thorough understanding of the degradation processes occurring in the battery cells. (iii) Reduction of battery cost; a way to reduce costs, increase battery residual value and improve sustainability is to consider second life uses of batteries used in electric vehicle application. These batteries are still operational and suitable to less restrictive conditions, such as those for stationary and renewable energy application. Therefore, possible second life opportunities have been identified and further assessed. In this paper, the main ageing effects of lithium ion batteries are explained. Next, an overview of different validated battery models will be discussed. Finally, a methodology for assessing the performance of the battery cells in a second life application is presented.

Beyond the plug and socket: Towards safe standardized charging infrastructures

This paper will present the current evolution in the field of charging infrastructure standardization, highlighting the main development areas of safety, compatibility and performance, also giving special interest to ongoing European developments in the field as well as to the residential charging field.

Influence of pulse variations on the parameters of first order empirical Li-ion battery model

Battery performance and safety constitute a bottleneck for electric vehicles to penetrate the car market. Online battery models are one of the engineering tools to enhance their performance. Empirical battery models form the subject of many scientific publications. In this paper a study, is performed of the usefulness of the first order impedance model through the consistency of the parameters under changes in the calibration signal, i.e. the current pulse. It can be concluded that simple first order models show little potential to really increase battery performance. Only the equivalent series resistance of the first order impedance model is insensitive to small variations of the calibration signal.

On the Ageing of High Energy Lithium-Ion Batteries—Comprehensive Electrochemical Diffusivity Studies of Harvested Nickel Manganese Cobalt Electrodes

This paper examines the impact of the characterisation technique considered for the determination of the Li+ solid state diffusion coefficient in uncycled as in cycled Nickel Manganese Cobalt oxide (NMC) electrodes. As major characterisation techniques, Cyclic Voltammetry (CV), Galvanostatic Intermittent Titration Technique (GITT) and Electrochemical Impedance Spectroscopy (EIS) were systematically investigated. Li+ diffusion coefficients during the lithiation process of the uncycled and cycled electrodes determined by CV at 3.71 V are shown to be equal to 3.48×10−10 cm2·s−1 and 1.56×10−10 cm2·s−1 , respectively. The dependency of the Li+ diffusion with the lithium content in the electrodes is further studied in this paper with GITT and EIS. Diffusion coefficients calculated by GITT and EIS characterisations are shown to be in the range between 1.76×10−15 cm2·s−1 and 4.06×10−12 cm2·s−1, while demonstrating the same decreasing trend with the lithiation process of the electrodes. For both electrode types, diffusion coefficients calculated by CV show greater values compared to those determined by GITT and EIS. With ageing, CV and EIS techniques lead to diffusion coefficients in the electrodes at 3.71 V that are decreasing, in contrast to GITT for which results indicate increasing diffusion coefficient. After long-term cycling, ratios of the diffusion coefficients determined by GITT compared to CV become more significant with an increase about 1 order of magnitude, while no significant variation is seen between the diffusion coefficients calculated from EIS in comparison to CV.