Experimental detection of fuel leakage in solid oxide fuel cells based on voltage signals.

Fuel leakage detection is crucial for solid oxide fuel cells (SOFCs) as fuel leakage significantly reduces the reliability and lifetime of SOFC devices. In this study, fuel leakage detection using voltage signals is thoroughly investigated. Rectangular SOFCs with four segmented cathodes are prepared and tested with fuel leakage along the seals. Voltammetric tests show that the ring-shaped area on the current-voltage curve is primarily caused by a delay of gas diffusion. Such a ring-shaped area is exacerbated by fuel leakage but is not sufficient as an indicator for detecting fuel leakage. Additionally, the open-circuit voltages measured at all segmented cathodes are well below the theoretical potential of the fuel gas. This is because a localized steam electrolysis circuit is formed when fuel leakage occurs. The measured open-circuit voltage is the potential difference between the two interconnectors in the closed electrolysis circuit. This work contributes to the accurate detection of fuel leakage and the commercialization of SOFCs. [Display omitted] • OCVs tested with fuel leakage are well below equilibrium potential. • Fuel leakage causes localized steam electrolysis. • The ring-shaped area on I–V curves results from a delay in gas diffusion. • Ring-shaped areas are not sufficient as indicators of fuel leakage. [ABSTRACT FROM AUTHOR]