Numerical and experimental study on thermal management of NCM-21700 Li-ion battery

Abstract

Energy and environmental challenges have been increasingly important in recent years, and electric vehicles equipped by lithium-ion batteries have demonstrated significant promise and advantages in addressing these issues. Thermal management of battery has emerged as an important criterion to consider in development and spread of lithium-ion batteries used in electric vehicles. In this work, thermal management of a NCM-21700 battery is performed experimentally and numerically. An electrochemical model is employed to simulate the irreversible and reversible heat generation in battery at various discharge rates. The temperature predictions are carried out at different values of discharge rate and depth of discharge (DoD) using CFD commercial software. The results show that predictions at each discharge rate are well matched with experimental data. Besides, the measured results indicate that with the increase of the discharge rate, the attenuation of the battery capacity also increases, and the loss of capacity is proportional to the increase of the discharge rate. When discharge rate is increased to 5C rate, internal temperature of battery would be greater than 50 °C, which is beyond operating temperature range. A significant temperature gradient is also appeared inside battery, indicating that the non-uniformity in the temperature is increased rapidly.