A Battery Thermal Management System Integrating Immersion Preheating and Immersion Cooling

Area of Science:

• Battery thermal management systems
• Thermodynamics
• Energy efficiency

Background:

• Immersion fluid-based battery thermal management systems (BTMS) are gaining traction.
• Limited research exists on integrating preheating and cooling functions within a single immersion BTMS.
• Developing all-climate BTMS solutions is crucial for electric vehicle performance and longevity.

Purpose of the Study:

• To design and investigate an immersion BTMS that combines preheating and cooling capabilities.
• To determine the optimal parameters for preheating performance and energy efficiency.
• To evaluate the cooling effectiveness of the integrated BTMS under diverse ambient temperatures.

Main Methods:

• Design of a novel immersion BTMS integrating preheating and cooling.
• Experimental investigation of preheating performance at -20 °C ambient temperature.
• Simulation and analysis of cooling performance at 25 °C and 40 °C ambient temperatures during high-rate discharge.

Main Results:

• Optimal preheating parameters identified: 2 L·min^-1 flow rate, 15 °C inlet temperature, 600 s duration, achieving a 14.1 °C average temperature and 3.18 °C·min^-1 rise rate at -20 °C.
• The integrated BTMS effectively controlled battery module maximum temperature difference (ΔT_max) below 3.08 °C and 28.48 °C at 25 °C ambient.
• Under 40 °C ambient conditions, ΔT_max and maximum battery temperature were maintained below 3.21 °C and 28.5 °C during 3 C discharge.

Conclusions:

• The designed immersion BTMS successfully integrates preheating and cooling functions for all-climate operation.
• Optimized preheating strategies enhance energy efficiency and heating performance in cold environments.
• The system demonstrates robust thermal control, ensuring battery safety and performance across a wide range of operating temperatures.