Modeling of Phase Change Materials in Electric Vehicle Battery Thermal Management

Abstract The thermal management of lithium-ion batteries is critical for ensuring performance, safety, and longevity in electric vehicle (EV) applications. This study presents a thermal analysis of a cylindrical 18650 lithium-ion battery under phase change material (PCM)-assisted conditions across various discharge rates. Using a 3D electrochemical–thermal coupled model based on the Multi-Scale Multi-Domain (MSMD) framework in ANSYS Fluent, the simulation captures detailed heat generation and transport dynamics. Results show that PCM integration significantly suppresses peak temperatures and enhances thermal uniformity, particularly at higher discharge rates. Notably, the maximum temperature reduction achieved was 48.16 K (10.95%) at a 2.0C discharge rate, demonstrating the PCM’s effectiveness in delaying thermal peaks and mitigating thermal stress. These insights affirm the potential of passive PCM-based thermal management for improving the safety and reliability of high-performance battery systems.