Investigation of the ir properties of 18650 battery cells

In this thesis study, the temperature changes of Lithium ion batteries that produced by Aspilsan, with a nickel-rich lithium-nickel-manganese-cobalt oxide (NMC) chemical structure, 2800 mAh discharge capacity and 230Wh/kg energy density, were examined in different charge and discharge states. A special box was designed to observe the temperature change of the batteries and temperature monitoring was carried out with a thermal camera for C/2, C and 3C/2 charge and discharge rates by applying constant current and for charge and discharge rates with variable current. The obtained images were analyzed according to temperature differences, and the maximum and minimum temperature values were examined graphically for each charge-discharge situation. When the results were evaluated, it was observed that the charge and discharge states showed linear changes with temperature.