A Semi-Empirical Lumped Model Applied on Simulation Analysis of Lithium-Ion Batteries with High Discharge Rate

The demand for a strong discharge capacity in lithium-ion batteries is increasing. However, there are few models and correlation analysis for special lithium-ion batteries with ultra-high discharge capacity in the existing research, and the existing conventional discharge rate model prediction is not satisfactory. Based on the single particle theory, a simplified lumped semi-empirical model containing multiple classes of overpotential and heat generation terms was established. The lithium-ion battery with high discharge rate capability was tested at large currents. The reliability and accuracy of the model were verified. The root mean square errors for the discharge current and temperature were respectively less than 30 mV and 2.8 °C at discharge rates above 30 C. The maximum relative error of the voltage was only 2.4%, which was the highest level of prediction accuracy known to the authors. Based on the model, the contribution from the various heat generation sources during the discharge process was analyzed. This model could be easily applied to the analysis and design of battery modules without the detailed information of cell materials.