Investigation on cold start of polymer electrolyte membrane fuel cells stacks with diverse cathode flow fields

Abstract

The shape of gas flow field determines the distribution of reactive gas and the drainage performance so it has a significant impact on cold start performance. This work designs three novel cathode flow fields of stacks through variable cross-section design to improve drainage, which are the single variable section serpentine flow field, the variable section interdigitate flow field and the variable section parallel flow field. The cold start characteristics and internal behavior of diverse novel stack flow fields are investigated by segmented cell technology. The results show that stack with the single variable section serpentine flow field realizes the fastest cold start when the temperature is below −5 °C. However, the variable section interdigitate flow field displays the shortest cold start time when the temperature is above −5 °C. The evolution of the current density distribution of the single cell in different position of the same stack is inconsistent during cold start. The key regions with strong electrochemical performance of different stack flow fields are found. The performance degradation of the stack with the single variable section serpentine flow field is the lowest when start fails. This work can supply experimental support for the selection of flow fields for cold start.