ELEKTRİKLİ ARAÇLARDA KULLANILAN 21700 TİPİ LİTYUM-İYON BATARYA PAKETLERİNDE FARKLI SOĞUTMA YAKLAŞIMLARININ SAYISAL OLARAK İNCELENMESİ
A NUMERICAL INVESTIGATION OF DIFFERENT COOLING APPROACHES IN 21700-TYPE LITHIUMION BATTERY PACKS USED IN ELECTRIC VEHICLES

Summary/Abstract: The performance, safety, and service life of lithium-ion batteries used in electric vehicles are highly dependent on operating temperature. Heat generation during charging and discharging processes, particularly under high C-rate conditions, can lead to elevated cell temperatures and degradation of battery performance. Therefore, the development of effective battery thermal management systems has become a critical research area in electric vehicle technologies. In this study, the thermal behavior of a battery pack consisting of 24 cylindrical 21700 lithium-ion cells was numerically investigated. Air and water cooling systems were evaluated under both natural and forced convection conditions, while the effects of J-, T-, U-, and Z-type flow channel configurations on thermal performance were comparatively analyzed. Numerical simulations were conducted using ANSYS Fluent software, and four different operating conditions (0.5C, 1C, 2C, and 3C) were considered to represent varying load levels. Maximum cell temperature (Tcell,max), average cell temperature (Tcell,avg), and battery pack temperature difference (ΔTpack) were used as the main performance indicators. The results revealed that increasing C-rate significantly increased cell temperatures, highlighting the importance of effective thermal management under high-load conditions. Water-cooled systems exhibited lower temperature levels than air-cooled systems under all operating conditions. In addition, forced convection generally provided superior cooling performance, whereas flow channel geometry was found to have a substantial influence on temperature distribution within the battery pack. Under 3C operating conditions, the lowest maximum cell temperature of 302.30 K was obtained in the J-type water-cooled forced-flow configuration. Overall, the findings indicate that liquid cooling offers a more effective thermal management solution for high-power electric vehicle applications and that channel design is a critical parameter affecting system performance.

• Details
• Contents