Experimental investigation of the dynamic characteristic and performance improvement of kW-grade air-cooled fuel cells

•The water and thermal balance of the air-cooled fuel cell is researched.•The flooding degree of the kW-grade fuel cell is investigated.•The efficiency of the stack can be improved by 3-–5%. Air-cooled proton exchange membrane fuel cells (AC-PEMFC) have wide applications due to their simple structure, and high efficiency. However, AC-PEMFC also needs effective methods to further improve the dynamic response and output power in the kW-grade power. Thus, this paper analyzed the dynamic characteristics and stability of the designed kW-grade AC-PEMFC at the beginning. Then, the effect of purging and active short-circuit activation strategy (ASC) are studied to solve the flooding and Pt oxidation problems, respectively. The results are as follows: (1) The AC-PEMFC capability of water and thermal self-regulation is limited in high power. Thus, active water management strategies based on flooding degree need to be researched; (2) To improve performance consistency and stability of the system, the ASC has high effectiveness on the performance improvement and dynamic performance consistency due to Pt catalyst oxidation prevention, note that the operating efficiency of the stack can be effectively improved 3-5% by using ASC. These results provide a novel reference for portable power source design and unmanned aerial vehicle design to improve the performance of kW-grade AC-PEMFC.