A novel thermal management for PEM fuel cell stack combining phase change materials with liquid cooling under low temperature condition

In this study, a low-temperature thermal management system (TMS) that combines a phase-change material (PCM) with liquid cooling for the cold start of a proton exchange membrane fuel cell (PEMFC) is introduced. The proposed system effectively utilizes the waste heat generated during the fuel cell operation to heat the PCM. After shutdown, the heat released during the PCM phase change process is transferred to the stack via a coolant pump, thus maintaining the stack temperature above the minimum startup threshold. A comprehensive thermal model of the proposed system is established and validated using numerical simulations. The temperature variations within the stack were evaluated under various environmental conditions, material properties, and coolant- pump control parameters. The results demonstrate that the TMS can sustain the stack temperature above 0 °C for 63.36 h in an environment at −20 °C. Furthermore, compared with passive thermal management, the proposed system has better temperature uniformity and an 11.71 % reduction in the stack startup time at 0 °C due to the proper loop design, which prevents the PCM from absorbing heat from the stack. This study provides innovative solutions to address the challenges associated with cold starts and is a valuable reference for future TMS designs.