Passive thermal management for PEM fuel cell stack under cold weather condition using phase change materials (PCM)

• An innovative concept of the passive thermal management using PCM and insulator for fuel cell in cold climates.
• The stack temperature can be kept above freezing for around two days.
• Several design factors are investigated with regard to the thermal management.
• The proposed concept can alleviate stack from performance degradation, long term durability and cold start-up issues.
• The result shows potential application for the automotive fuel cell operation in cold climates.

In cold weather conditions, i.e. winter, the polymer electrolyte membrane (PEM) fuel cell stacks typically undergo freeze–thaw cycle operations which leads to performance degradation, long term durability, and start-up issues. In this study, we propose an innovative passive thermal management strategy to alleviate stack from freeze–thaw cycles by utilizing phase change materials (PCM) and insulator to maintain the stack temperature above its freezing point. The impact of the passive thermal management of PCM is studied via mathematical model of the transient two-dimensional two-phase flow of solid–liquid PCM, insulator and PEM fuel cell stack comprising 20 cells, and associated conservation of mass, momentum and energy. The effect of key design and operating parameters are evaluated with regards to stack temperature. The model results indicate that the stack temperature can be maintained well above freezing temperature for around two days which shows potential for PEM fuel cell application, especially in automotive area. The results provide useful design guidelines for passive thermal management in PEM fuel cell stacks under cold weather conditions.