Thermal management of modern electric vehicle battery systems (MEVBS)

The operating temperature of Li-ion batteries used in modern electric vehicles should be maintained within an allowable range to avoid thermal runaway and degradation. One of the most challenging issues faced by the automobile industry is providing proper thermal management mechanisms to avert thermal runaways. In this work, the effect of operating parameters like volumetric heat generation (S̅q), conduction–convection parameter (ζcc), Reynolds number (Re), and Aspect ratio (Ar) on the thermal behavior of a prismatic battery cell is investigated numerically considering a realistic conjugate condition at the battery cell and coolant interface. Air is selected as the coolant that carries the heat generated uniformly in the modern battery cell during charging or discharging from its surface. For variations in S̅q from 0.1 to 1.0, ζcc from 0.06 to 0.1, Re from 250 to 2000, and Ar from 10 to 35, the temperature distribution, as well as maximum temperature variation in the battery cell, is determined. Further, the occurrence of the critical threshold of temperature and the necessary change in these operating parameters to avoid thermal runaway is proposed. Finally, the effect of flow Reynolds number and channel spacing on average Pressure and average Nusselt number is also discussed in this study. From the exhaustive analysis on the effect of considered parameters, it is observed that apart from heat generation parameter S̅q, other parameters like ζcc and Re play a prominent role in reducing the maximum temperature of the battery cell. However, Ar has a negligible impact on the thermal performance of battery cell irrespective of any value of other parameters considered in this study. It was interesting to find that for Re> 1000, the impact on temperature profiles of the battery cell is minimal, while the other parameters were either kept constant or varying, putting a limit to higher values of Re.