Study on the mechanism of destruction triggering of membrane electrode assembly of hydrogen fuel cell.

• Mechanical and thermal destruction plays triggering role of MEA destruction. • External stress occurs at GDL and PEM interface, mainly causing surface cracking. • Internal stress is caused by moisture in PEM, causing MEA deformation and PEM tear. • Mechanical destruction and internal flow creates a vicious circle killing fuel cell. In this paper, the mechanism of the destruction triggering of the membrane electrode assembly (MEA) of hydrogen fuel cell is studied. It is proposed that electrochemical destruction is the main cause of MEA failure and the result of other damages. Electron microscopy experiments are carried out on the MEA after 20 h of operation, the MEA after clamping, and the MEA after water immersion freezing, then the trigger role of mechanical destruction and thermal destruction in MEA is revealed. The analysis shows that the mechanical destruction, thermal destruction, electrochemical destruction and the internal mass transfer process of the MEA are coupled to each other to cause MEA destruction. Mechanical and thermal damage play a trigger role in the ultimate destruction and failure of the MEA, which will affect the flow mass transfer process, the flux of the working gasses in the MEA is abnormally increased, resulting in further component destruction and negative electrochemical reaction. Preventing MEA from mechanical and thermal destruction plays a key part of improving its durability. On the one hand, the external clamping should avoid stress points in the MEA area to minimize the external stress. On the other hand, the proton exchange membrane requires lower swelling rate and proper drainage measures in the off state. [ABSTRACT FROM AUTHOR]