Optimization of the internal fin in a phase-change-material module for battery thermal management

As an excellent option that has wide application in the thermal management system to ensure the safety of lithium-ion batteries, phase change material (PCM) cooling technology is highly desirable but the low thermal conductivity of PCMs limits its application. Herein, a series of experiments are conducted with and without fins to investigate the effects of fin configurations. The experimental results show that longitudinal fins are beneficial for dissipating the accumulated heat at the bottom and air convection with the ambient, while circular fins present better heat conduction due to their larger surface area. Regarding the fin number, in a limited-space module, increasing fins does not necessary mean an increase in fin efficiency, while the use of four longitudinal fins displays the highest efficiency for 18650-battery module in the current work, resulting a temperature drop from 36.9 to 34.2 °C in the rectangular finned module. Finally, based on these conclusions, an optimized PCM module combining various fins is designed and tested for its thermal performance, where a greater balance between the heat absorption and heat dissipation is obtained with lower maximum battery temperature and smaller temperature range. The T_max in the optimized finned module is 29.1 °C at 1 C charging rate, decreasing by 5.5%, in comparison to that of the rectangular-finned module. Such an experimental study can not only provide new references for the experimental data in the practical battery module but also broaden minds on the design for PCM-based finned modules.