Numerical study on the heat transfer enhancement and fin size optimization of hybrid battery thermal management system

OpenAlex İngilizce

Abstract Thermal management is critical in ensuring that safety, functionality, and battery life in lithium-ion batteries are not compromised, especially when undergoing high-discharge currents. In traditional battery thermal management systems (BTMS), there are limitations in effectively suppressing a relatively high rate of temperature increases when in operation. To address this problem in traditional BTMS, this study investigates how changes in metal fin thickness affect heat transfer and temperature regulation in a BTMS that has a phase change material (PCM) to suppress overheating. The analysis considered two different types of PCMs with different thermal properties and thicknesses of 3 mm and 5 mm. The thicknesses of metal fins for both discharges of 5C and 8C were optimized. The generation of actual heat in batteries undergoing operation has been assumed to have a temperature dependency expressed as the lumped-capacity resistance. With a 5C discharge rate, the temperatures of batteries in the system with the first PCM were lower than those in the system with the second PCM. However, in a scenario involving a rate of 8C, temperatures were better controlled with a lower thickness of layers in the second PCM. On the other hand, for a thicker setup, temperatures were better controlled in a system with the first PCM. Moreover, temperatures for a safe operation were obtained only for a setup consisting of a 5 mm layer of PCM and 8 mm fins in a system with an 8C discharge rate. The current study explains how a battery can benefit thermally when a specific fin and PCM are used. Results obtained illustrate that batteries can benefit thermally when a suitable fin and PCM are selected. The study can provide important information required for designing advanced battery thermal management systems to improve safety and efficiency in batteries that power electric vehicles.