P. Van den Bossche

Using Super Capacitor Based Energy Storage to Improve Power Quality in Distributed Power Generation

Distributed power generation will be formed in many weak distribution networks, after renewable energy sources are connected to them. It is very important to increase the reliability and efficiency of using these renewable energy sources. By using DVR (dynamic voltage restorer), the power quality problem in distributed power generation (e.g. voltage fluctuation) can effectively be solved. In this paper, super capacitor based energy storage will be used as the peak power unit, to ensure the power quality on the both sides of the DVR during short time and on the one side of the DVR during long time duration. The proposed control methods of each inverter and converter have been verified in Matlab simulation and tested in our laboratory. High power quality can be achieved in distributed power generation with the presented systems

Lithium-ion capacitor — Advanced technology for rechargeable energy storage systems

This paper presents the electrical and thermal behaviour of an advanced lithium-ion capacitor (LIC) based rechargeable energy storage systems. In the proposed study, an extended statistical analysis has been performed to evaluate the main electrical parameters such as resistance, power, capacitance, rate capabilities, variation between cells and thermal parameters. Based on the performed analysis, an electrical model has been developed for dimensioning and evaluation of various applications based on lithium-ion capacitor technology.

SOH Estimation and Prediction for NMC Cells Based on Degradation Mechanism Detection

Accurate on board State of Health (SOH) estimation is a key Battery Management System (BMS) function to provide optimal management of the battery system under control. In this regard, this paper presents an extensive study of the degradation mechanism of NMC/Graphite cells based on the study of both incremental capacity (IC) and differential voltage (DV) curves. Moreover, based on the obtained IC curves, a linear relationship was identified between capacity and IC peak intensity for both calendar and cycling ageing. This novel characteristic allows to estimate and even to predict the SOH of NMC/graphite cells.

Lithium Iron Phosphate - Assessment of Calendar Life and Change of Battery Parameters

This paper represents the calendar life cycle test results of a 7Ah lithium iron phosphate battery cell. In the proposed article and extended analysis has been carried out for the main aging parameters during calendar life and the associated impact of the used battery model. From the analysis, it has been showed that the impact of high temperatures and state of charge is harmful for the lifetime of the battery. Therefore, there is a need for having a dedicated control strategy for keeping the battery in the most appropriate operating condition. The FreedomCar battery model parameters have been analyzed during calendar life.

Electro-Thermal Modeling of New Prismatic Lithium-Ion Capacitors

Due to increasing demand of using high energy and high power storages applicable in different applications such as hybrid electric vehicles, hybrid Lithium Ion Capacitors have been taken into account more than ever. In this paper a second order model is considered for and based on that model and HPPC (hybrid pulse power characterization) test, parameters have been identified. Then based on evaluation of internal resistance total power losses have been calculated. Regarding to the cell temperature prediction, a first order model has been considered and based on measured surface temperature and also calculated power losses, parameters of thermal model have been identified. At the end both electrical and thermal models have been merged and final model has been validated.

Battery thermal modelling - Assessment of heat distribution and optimization of battery design concept

The goal of this study was to conduct a model based, thermal analysis, of a large cylindrical LFP Lithium-iron Phosphate, lithium-ion battery cell. At the end, the electrochemical-thermal type of model, developed in this study, succeeded, in both determining the temperature of the cell that was previously measured experimentally; as well as predicting an overview of the temperature distribution, occuring inside the cell with a deviation from the experimental values of only 5% in order of magnitude. For this purpose, a wide range of different operating conditions, and loading cycles have been applied to the cell, which were also simulated numerically. The results then first obtained, could clearly demonstrate the importance of the increase of the temperature of the cell, caused by the increase of the current rate, observed for both surface and core regions. Moreover, for an optimization of the battery design concept, a second improved model, involving a 2D modelling of the internal layered configuration of a cross section of the cell, was developed as well. By comparing the results from this last cross sectional model, with those belonging to the first achieved lumped thermal model of the cell, a better understanding and visualization of the internal temperature distribution, could be reached for the first time for such type of large format battery cell. Principally, the comparison of the models, stressed the existing influence, of the way to model the internal cell configuration, on the temperature distribution occuring inside the cell, and on its associated temperature values obtained for both surface and core regions.

Influence of selective harmonic elimination technique of Multi-Level DC/DC converter on second-life battery performances

This paper is part of a research project, which aims to investigate the possibilities of using the second life batteries after their replacement from the plug-in electric vehicles (PHEVs), hybrid electric vehicles (HEVs) and battery electric vehicles (EVs) for smart grid applications. In these applications, the power electronics converters (PECs) play a key role in the development of a high performance integrated system. This paper shows that the performance of the batteries will be affected by the performance of the PECs, which are utilized to achieve the integration of the batteries with the smart grid. Therefore, this paper demonstrates the impact of the Multi-Level DC/DC Converter (MLDC) on the performances of the battery system. The Selected Harmonic Elimination (SHE) technique is used to realize the control system of the Multi-Level DC/DC Converter (MLDC). In addition, the battery model of a Lithium-ion iron phosphate (LFP) with different capacities (7Ah, 14Ah and 20Ah) is used to investigate the impact of the switching angles and the voltage levels of each module on the performance of each battery module. This system (including the battery modules, MLDC and electric load) is designed and verified by using MATLAB/Simulink environment. Furthermore, this paper provide an extended analysis to select the proper switching angles for different units of MLDC, which can be used for both of designing the control strategy of second life battery and achieving less Total Harmonic Distortion (THD) at AC side.