Transient Finite Element Simulation of a Lithium-Ion Battery Pack Thermal Management System Based on Latent Heat System Materials

High-intensity use of lithium-ion battery packs can lead to overheating. When heat generated from battery use exceeds the rate at which its surroundings dissipate the heat, thermal runaway occurs. 12-cell and 84-cell assemblies of lithium-ion NCR18650B batteries exceeded the manufacturer maximum temperature after a discharge at constant power, 1P. To passively regulate the temperature of the battery packs, a phase-change material was used as a latent heat system, transferring heat from the cells to the material during operation. Utilizing ANSYS, finite element analysis simulations were performed to show the advantage of an expanded graphite matrix infiltrated with paraffin wax. Material properties of the mixture were studied with differential scanning calorimetry and an ideal mixture of 25% EG and 75% PureTemp 60 paraffin wax was found. The results verified that the mixture significantly lowered the temperature of the cells; providing a cost efficient, accessible solution to counter increased operating temperatures.