Characterization of biaxial fatigue durability for fuel cell membranes using pressure-loaded blisters

In this study, a customized pressure-loaded blister test device capable of achieving sinusoidal control of pressure was developed to investigate the biaxial fatigue durability of proton exchange membrane (PEM) for fuel cells. The effect of temperature, relative humidity and stress state on biaxial fatigue life was investigated, and the biaxial stress-strain curves under different temperature and relative humidity conditions were also compared. It is found that increasing pressure induces higher biaxial stress and exacerbates the accumulation of plastic strain in the membrane, which adversely affects biaxial fatigue lifetime of PEM. Increasing temperature and decreasing humidity reduces the biaxial yield strength, thereby reducing the fatigue life of membrane. In addition, lowering temperature can lead to a transition in the failure mode from complete rupture to leakage failure. The increase in air pressure ratio, Rp, (minimum to maximum pressure ratio) also leads to premature membrane failure. •A blister test device is developed for cyclic sinusoidal pressure loading.•Higher pressure causes larger biaxial stress and strain in the membrane.•High temperature and low humidity reduce the biaxial fatigue life of PEMs.•Lowering temperature shifts biaxial fatigue failure mode from rupture to leakage.•Fatigue life is dominated by both creep and fatigue at lower biaxial stresses.