Thermal management system using pulsating heat pipe of cylindrical battery cell

This study presents experimental investigations on the optimal design and operating conditions of pulsating heat pipe (PHP) cooling systems for cylindrical 18650 cells in electric vehicles with a special top heating mode. The research explores the effects of various parameters, including the number of turns, working fluid, filling ratio, coolant temperature, and condenser length, on the PHP system's performance. A cylindrical 3D PHP module was designed based on the flat-type PHP experimental results and evaluated as a cooling system for 18650 cells. The study highlights that the number of turns and working fluid significantly influence the PHP system's performance, with methanol identified as the most suitable working fluid. The optimal number of turns for continuous operation was determined to be 8 to 9. The condenser length was found to play a crucial role in enhancing heat transfer efficiency. The PHP system's continuous flow of working fluid ensured stable temperature profiles and prevented overheating. The research recommends a 9-turn PHP system with methanol as the working fluid and 10 %-15 % filling ratio for cooling two 18650 cylindrical cells. Maintaining cooling water temperature below 25 degrees C and considering specific orientation angles further improved the PHP system's cooling performance. Overall, these findings provide valuable insights into the optimal design and operating conditions of PHP cooling systems for electric vehicle batteries, leading to stable and efficient cooling, prolonged battery life, and improved electric vehicle efficiency. These results are vital for researchers and engineers working in the field of electric vehicle battery cooling systems and can serve as a foundation for future studies in this area.