Modular Stack‐Internal Air Humidification Concept‐Verification in a 1 kW Stack

Abstract

The analysis of the complete H2/air polymer electrolyte fuel cell system shows that process air humidification is one of the biggest obstacles for a high performance portable system in the kW range. Therefore, a new concept, with passive process air humidification integrated into the stack, has been developed. Humidification in each cell makes the process independent from the number of cells and the operation mode, thus making the concept fully scalable. Without external humidification the system is simpler, smaller, and cheaper. The humidification of the process air is achieved by transfer of product water from the exhaust air, through part of the membrane, to the dry intake air. Tests have shown that cells using the concept of internal humidification and operated with dry air at 70 ° have almost the same performance as when operated with external humidification. A 42‐cell stack with this internal humidification concept was built and integrated into a portable 1 kW power generator system.

Humidification strategy for polymer electrolyte membrane fuel cells – A review

“…A novel humidification concept is developed through separating the membrane into an active area and a humidification area [14]. In this design, the fresh gas flows into the humidification section first and the exhaust gas from the reaction section also flows into the humidification section to humidify the fresh gas.…”

Design methodology for membrane-based plate-and-frame fuel cell humidifiers

“…One method of internal humidification relies on special fuel cell stack designs or flow field pathways [3,4]. These designs distribute the water within the fuel cell, but require greater stack complexity, potentially specialized porous flow field plate materials, and are often less effective than external humidification.…”