Optimizing BTM of HV Battery Pack for Automotive Application Using Electro-Thermal Simulation

One of the important systems in the design of an electric vehicle is the Battery Thermal Management System (BTMS) which directly affects the operation of the battery in terms of safety, performance, and life. BTMS plays a vital role in calculating the cooling requirements of an EV throughout its operation such that the battery pack maintains uniform cell temperatures, avoids premature capacity loss, and increases the range. Thermal conditions of the battery packs vary at different topographies and ambient conditions of the geography, so evaluating and choosing the worst-case condition must be part of every design process. It is significant to predict the heat loads generated due to electrochemistry in the module during the charging and discharging of the vehicle. The present study focuses on the thermal management of a battery pack consisting of 15 modules having a 7S2P configuration with an active cooling system at various flow rates ranging from 10 to 30 lpm (Liters Per Minute) and optimizing the power requirement of BTMS using the Ansys Fluent Battery Model. The Equivalent Circuit Model (ECM) is chosen to represent the dynamic characteristics of the cell through Hybrid Power Pulse Characteristics (HPPC) data. In this paper, a single cell of 80Ah is validated with the experimental data for a real drive cycle. The mean temperature of the cell is underpredicted by 8%. It is concluded from the present study that the optimum flow rate of 10 to 20 lpm is sufficient to maintain the cell’s maximum temperature within 35 deg C for the given drive cycle.