Experimental and numerical investigations on thermal management of lithium-ion battery packs with integration of myristyl alcohol and heat pipes

Effective thermal management of lithium-ion battery (LIB) is essential for its performance, safety, and life. In the present study, a novel hybrid battery thermal management system (BTMS) integrating phase change material (PCM), heat pipes, and air-based cooling, including mist-assisted convection, is experimentally and numerically investigated. LIB consisting of 32 cylindrical cells is designed and fabricated, with myristyl alcohol as PCM and custom-designed heat pipes embedded within the intercellular spaces. Experiments are conducted under various discharge currents, cooling configurations, and different cooling strategies at condenser section of heat pipes. In addition, dedicated experiments are performed for heat generation characteristics of cells and effective thermal conductivity of heat pipes, which are subsequently utilized for numerical simulation of three-dimensional transient conjugate heat transfer model developed. Results demonstrate that PCM significantly improves temperature uniformity within the battery pack, while heat pipes enhance heat transport to ambient. Forced convection at condenser section reduces temperature rise from 8.6 K to 6.33 K and decreases the maximum temperature difference from 3.5 K to 2.35 K at discharge current of 12 A. Integration of heat pipes results in 6% reduction in temperature rise and 8.4% reduction in temperature non-uniformity compared to the PCM-only configuration. Mist-assisted cooling enhances heat dissipation under high thermal loads. Proposed BTMS is capable of maintaining maximum battery temperature and temperature non-uniformity below the threshold values at all tested conditions. The findings provide valuable insights into thermo-fluid behaviour of hybrid BTMSs and demonstrate their potential for advanced battery thermal management in electric vehicles.