Jelle Smekens

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.

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.

Electrochemical impedance spectroscopy characterization and parameterization of lithium nickel manganese cobalt oxide pouch cells: dependency analysis of temperature and state of charge

Characterizing lithium-ion batteries is of prime importance as it helps in understanding the safety, working temperature, voltage range, and power capabilities. Based on these results, we can then choose operating conditions which include safety protocols, application, and working environment. In this study, EIS studies of commercially available 20-Ah lithium-ion battery and a 28-Ah prototype cell with nickel manganese cobalt oxide (NMC)/graphite chemistry are used to determine the contribution of temperature and state of charge (SoC) towards the electrochemical impedance spectroscopy. These cells are manufactured for electric vehicle (EV) application. The electrode structure, particle size, stacking of the electrodes, and other entities for both the cells are provided to compare the similarities and differences between both the cells. Equivalent circuit modeling is used to analyze and comprehend the variation in impedance spectrum obtained for both the cells. It is observed that the ohmic resistance varies with both temperature and SoC and the variation with temperature is more significant for the prototype cell. The prototype cell showed better charge-transfer characteristics at lower temperatures when compared to the commercial cell.