Thermal management of electric vehicle batteries using multiple PCMs
Esra Ahmed Khodadad, Bashir Eskander Kareem, Darawan Bazyan Dhahir, Ahmed Mohammed Adham
Abstract
Electric car batteries experience high discharge rates that can result in elevated temperatures. To prevent thermal runaway and ensure safe operation, it is crucial to effectively manage and maintain the battery temperature within its optimal operating range. The use of paraffin-based phase change materials (PCMs) for cooling lithium-ion batteries is an effective passive cooling method. PCMs are highly effective for thermal energy storage owing to their high heat-storage capacity. However, their limited thermal conductivity restricts their effectiveness in thermal-management applications. This study conducted a numerical investigation into the thermal management of 18650 lithium-ion batteries using multiple PCMs, employing the commercial software ANSYS Fluent. The analysis involved uniform heat dissipation from the center of a cylindrical battery, which was submerged in a paraffin-based PCM and enclosed within a metal housing. A 2D model was used to reduce the computational costs by leveraging the geometric symmetry of the system. During battery discharge, individual PCMs with melting points of 35, 44, and 54°C fully melt at 1,000, 4,000, and 7,000 s, respectively. In contrast, when using multiple PCMs with melting points of 38°C, 42°C, 44°C, 47°C, and 50°C, complete melting occurred at 1,900, 2,000, 2,750, 3,050, and 3,500 s, respectively, for the same total mass. The temperature difference between the top and bottom of the battery was up to 6°C for a single PCM, but this difference was significantly reduced by using multiple PCMs.