Passive thermal management of a lithium-ion battery using carbon fiber loaded phase change material: comparison and optimization

Abstract

Phase change materials (PCMs) are currently used for many heat management applications. However, the heat transfer performance of PCMs is limited by their low thermal diffusivities. This is a critical issue for high heat flux applications, such as in thermal management of lithium-ion (Li-ion) batteries. The present work aims at the study of heat transfer enhancement in a cylindrical Li-ion battery thermal management system consisting of a PCM (paraffin) loaded with randomly distributed and radially oriented carbon fibers. The system was simulated numerically under various cooling conditions, including naturally convecting air, in the presence of pure paraffin, and in the presence of carbon fiber loaded paraffin. The results for orderly arranged carbon fibers were compared with those of random distribution. Numerical results indicated that better battery thermal management can be achieved for the radially distributed carbon fiber arrangement in the PCM. The advantage of radial over random distributions can be due to the constant, uniform, and non-agglomerating distribution of carbon fibers under which thermo-physical properties of carbon fibers are better realized in the composite medium. The presence of carbon fibers with thermal conductivity of k=50W/m K in the PCM has caused a more uniform temperature profiles in the radial direction because of the improved thermal conductivities. The results of this research can be used as a guideline for designing battery thermal management system.