Electro-thermal modeling and experimental validation for lithium ion battery

Thermal management is crucial for improving the charge–discharge efficiency and cycling life of lithium ion battery. In this paper, a mathematical model coupling electronic conduction, mass transfer, energy balance and electrochemical mechanism is developed. Lithium ion diffusivity and chemical reaction rate of cathode material are estimated by comparing simulated results with experimental data of pulse test at various current charge–discharge rates (0.2C, 0.5C, 1C, 2C) and operating temperatures (0 °C, 10 °C, 25 °C, 55 °C). The modeling results are further validated in aspects of electrochemical performance, thermal performance and electrochemical-thermal coupling effects, which show well agreement between the modeling results and experimental results. The modeling results show that lithium ion concentration gradient in both liquid phase and solid phase are greatly affected by temperature, and the lithium ion concentration gradient increase when temperature decrease. This phenomenon results in the capacity losses and power loses of lithium ion battery during low temperature operation. The reversible heat generation during charging process is equal with the heat consumption during discharging process. It is also indicated that the reversible heat is dominant at low rate discharging process and irreversible heat is dominant at high rate discharging process. Proper cooling system should be added to keep battery temperature within safety range during high rate current charging/discharging.

► A quasi two-dimensional lithium ion battery model coupling electronic conduction, mass transfer, energy balance and electrochemical reactions.
► Comprehensive model validation at various current charge–discharge rates (0.2C, 0.5C, 1C, 2C) and temperatures (0 °C, 10 °C, 25 °C, 55 °C).
► Electro-thermal coupling effects of lithium ion battery.
► Detailed species concentration distributions.