Mathematical modeling of the thermal behavior of a lithium-ion battery at different discharge rates

 In the experimental study, the maximum battery temperature and temperature distribution of the ICR 26650 LiCoO2 battery in different discharge parameters were taken into account. The experiment was carried out according to the L18 orthogonal sequence with the Taguchi experiment design method, which is one of the experimental design methods. Experiments were designed with this sequence, 18 experiments were performed, and the levels of the factors decided by analyzing the experimental results were determined. The C-Rate (2 C-rate, 3 C-Rate, 4 C-Rate, 5 C-Rate, 6 C-Rate and 7 C-Rate), ambient temperature (293 K, 303 K and 313 K) and heat transfer coefficient (10 Wm-2 K-1 , 20 Wm-2 K-1 , 30 Wm-2 K -1 ) were decided for different parameters. Simulation studies on L18 orthogonal sequence were carried out in ANSYS Fluent program. The C-Rate factor was the most effective for the maximum battery temperature compared to other factors. The least effective factor was the heat transfer coefficient. 6 C-Rate, 293 K and 30 Wm-2 K-1 levels have been obtained at the values where the maximum battery temperature is the smallest and the best. Again, the C-Rate factor was the most effective on the temperature distribution, then the ambient temperature and the last heat transfer coefficient were effective. It was found that the temperature distribution was minimal at the 2 C-Rate, 313 K and 10 Wm-2 K-1 levels. According to the obtained ANOVA results, when 95% of the confidence interval is taken into account, it is stated that there is a statistically compatible relationship between Tmax and ΔTmax and C-rate. The results obtained from this study can be used in the design of thermal management systems of lithium-ion batteries.