Novel Z-Shaped Structure of Lithium-Ion Battery Packs and Optimization for Thermal Management

Thermal management of lithium-ion battery packs is a key technical problem that restricts the development of new-energy vehicles. The shape of air-cooled Lithium-ion battery packs is vital for thermal management system without replacing batteries. Here we proposed and optimized a novel Z-shaped battery pack structure, which was systematically analyzed and optimized by a computational fluid dynamics method. The results show that when the inlet airflow rate changes from 0.003-0.036 kg s(-1), the temperature difference increases (from 7.91 to 9.67 K), while the temperature nonuniformity of the battery packs increases (from 2.49 to 3.09 K). The maximum temperature, difference, and nonuniformity of temperature all increase in the initial phase with the increase of battery spacing when the battery spacing is 4 mm; the inflection point appears and then decreases gradually. Meanwhile, the cooling effect of the Z-shaped structure is improved greatly by adding deflectors and rounding-off chamfers. When the tilt angle of deflectors is 60 degrees and the radius of round chamfers is 5 mm, the maximum temperature of the battery packs decreases by 2.52 K; besides, the temperature difference and nonuniformity decreases significantly, which improves the performance of lithium-ion battery packs effectively. (C) 2019 American Society of Civil Engineers.