Thermal behaviour of Li-ion battery: An improved electrothermal model considering the effects of depth of discharge and temperature

The current paper presents a two-dimensional electrothermal model that evaluates the thermal and voltage behaviour of a LiFePO4-20 Ah Li-ion pouch cell. The electrothermal model considers the impact of depth of discharge (DoD) and temperature on heat generated inside Li-ion cells by precisely simulating the internal equivalent resistance and entropy change utilizing experimental data. The proposed electrothermal model is validated utilizing experimental data. The results for the temperature estimation utilizing the electrothermal model show a similar result for all discharge current rates. The temperature prediction for all the discharge current rates (C-rate) shows slightly more accurate and precise results toward the end of discharge of Li-ion pouch cell. Overall, the absolute maximum relative error for the temperature prediction is around 6.30 % at 4C discharge rate. Similarly, the voltage estimation shows a high level of accuracy compared to the experimental data, and the simulated voltage has slightly higher values than the experimental voltage data, but the voltage trend is similar to the experimental data. Overall, the simulated results obtained from the proposed electrothermal model exhibit similar trends and high accuracy when compared to the experimental data.