Improving thermal performance of battery at high current rate by using embedded heat pipe system

Abstract

This study establishes a resistance-based thermal model for the battery cooled by the heat pipe. Unlike the traditional thermal model, the proposed battery thermal model includes the influence of the battery temperature, state of charge (SOC) and current on the heat generation in the battery body. Moreover, it also integrates the heat generation inside the tabs to improve its prediction accuracy. The heat pipe model is developed based on the thermal resistance of its components, and this model is integrated with the battery thermal model to form the thermal model of the BTMS based on the embedded heat pipe system. Experiment are carried out to verify the prediction precision. At the level of the battery unit, the prediction error is within 1 °C. Then, the different heat pipe number, fin number and heat transfer coefficient at the condensation section of the heat pipe are used for the embedded heat pipe system in order to improve its cooling performance. According to the research results, increasing the heat pipe number can reduce the battery temperature and its difference. However, when the heat pipe number is over a certain threshold, both the battery temperature and temperature difference change little. Although the heat transfer coefficient has limited influence on the battery thermal behavior, increasing the heat transfer coefficient and fin number at the same time can reduces the battery temperature a lot. In addition, comparative studies show that the embedded heat pipe system significantly outperforms the bar-type heat pipe and flat heat pipe at an extreme high current rate.