5/3/2023 0 Comments Strong together by series![]() To meet the power requirements at tolerable currents, several lithium-ion cells are connected in series in a battery to achieve a higher system voltage. In this segment, lithium-ion batteries have gained acceptance in recent years due to their energy and power density. ![]() With the aim of reducing fossil fuels and creating an environmentally friendly mobility sector, battery systems are already playing a major role in the electrification of vehicles. More important, the balancing charges which are calculated iteratively within the used balancing algorithm show a strong correlation to the pure capacity losses and thus provide a new way to determine the capacity values of each cell individually without disassembling the battery.īattery systems are becoming increasingly important due to climate change and the associated trend towards using renewable energies. After the aging test, the battery was equipped with an active balancing system that maximizes capacity utilization. Lithium plating was also observed in the faster aging cells after cyclic aging, suggesting that this aging effect contributes significantly to the development of CtCV. The shifting Depth of Discharge (DoD) values among the cells further amplify CtCV. ![]() The results show that despite a theoretically perfect module design, Cell-to-Cell Variations (CtCV) occurred during aging. Differential Voltage Analysis (DVA), Electrochemical Impedance Spectrum (EIS), and relaxation measurements were performed to analyze the aging behavior of each cell. Extrinsic influences that affect cell aging were thus reduced to a minimum. For this purpose, the cells were virtually connected in a laboratory environment with the help of the test device as if they were operated together in a battery. During the test, special care was taken to ensure that the results were not influenced by either the module assembly or the module design. In this work, a battery consisting of eight commercial NMC/graphite cells connected in series was cycled to 60% of its initial capacity.
0 Comments
Leave a Reply. |