Project 2 Thermal modeling of battery pack

1. The objective is to simulate the thermal effects and compare life cycle performance at various temperatures, charge & discharge rates for a 10 cell series lithium-ion battery model using MATLAB.

• Firstly, let us connect the individual 10 cells in series.
• Then analyze the characteristics with different charge ad discharge cycles.
• Change the ambient temperature and analyze the results.

To connect the 10 cells in series, Battery (Table Based) block is used. It calculates no-load voltage using a lookup table and has options for the thermal port.

By simulating the thermal effects on the battery pack, we can calculate the SoC and life cycle of the battery pack. After a correction with the charging and discharging efficiency, a more accurate estimation can be achieved. The SOC can be then estimated by subtracting the DOD quantity from the SOH one. When the battery is open-circuited with zero current, the SOC is directly obtained from the relationship between the OCV and SOC.

An AC source has been connected to analyze the cyclic charge and discharge performance. The positive cycle will charge the battery and the negative cycle will discharge the battery. Peak amplitude has given 4.1A so that the charging/discharging doesn't go beyond the 1C rate.

The performance of the battery at 373.1k is such that it is going to peak voltage and lowest voltage. This is due to the degradation of the capacity of the battery's maximum charge and maximum discharge varies.

Thus, the thermal effects of the battery packs at different ambient temperatures for cycling charging/discharging have been analyzed and plotted.