Experimental exploration of finned cooling structure for the thermal management of lithium batteries with different discharge rate and materials

Lithium-ion batteries in electric vehicles generate heat continuously, leading to high temperature of the battery packs and significant temperature differences between the battery cells, which eventually deteriorate the performance and lifespan of lithium-ion batteries. Therefore, a novel battery thermal management system that equipped the battery pack with fins was proposed and experimentally studied in this paper. The thermal behavior of lithium-ion batteries with different discharge rates and fin thicknesses was investigated. The results show that under natural-convection conditions, the addition of fins restricted the significant increase of the battery pack temperature and improved the uniformity of temperature distribution in the battery pack. Additionally, thicker fins satisfied the temperature requirements at higher discharge rates and greater discharge depths. Under condition of 2C discharge at 80% depth of discharge, compared to no clearance structure the 1 mm and 3 mm aluminum finned structure decreased the maximum temperature rise and the maximum temperature difference by 26.5%, 40.8%, and 9.5%, 33.3%, respectively. However, the trade-offs and optimization between the thermal load, weight, and volume increase caused by the addition of fins should be further investigated.