A Battery Thermal Management System Integrating Immersion Preheating and Immersion Cooling

The battery thermal management system (BTMS) depending upon immersion fluid has received huge attention. However, rare reports have been focused on integrating the preheating and cooling functions on the immersion BTMS. Herein, we design a BTMS integrating immersion cooling and immersion preheating for all climates and investigate the impact of key factors on the preheating/cooling performance. For the preheating mode, adopting an inlet flow rate of 2 L·min^-1, an inlet temperature of 15 °C, and a preheating time of 600 s is optimal by considering both heating performance and energy efficiency under a low ambient temperature (<i>T</i> _a) of -20 °C. The corresponding minimum temperature, average temperature, maximum temperature difference (Δ<i>T</i> _max), and rate of temperature rise could achieve 11.81 °C, 14.1 °C, 3.18, and 3.18 °C·min^-1, respectively. For the cooling mode, the immersion BTMS could effectively control the Δ<i>T</i> _max and maximum temperature of the battery module below 3.08 and 28.48 °C, and 3.21 and 28.5 °C at a high-rate discharge of 3 C under a normal <i>T</i> _a of 25 °C and a high <i>T</i> _a of 40 °C, respectively.