Polymer electrolyte fuel cell (PEFC) usually consist of tens to hundreds of layers of membrane electrode assemblies (MEAs) to obtain the required electrical output. A defect in one of the MEAs in the stack can significantly degrade the performance of the entire stack. Therefore, we propose a non-contact method for detecting defects caused by electrolyte breakage, poor electrical contact between parts, and the presence of insulators after the stack is assembled. The purpose of this study is to apply this method to the inspection process of products at the time of shipment, thereby contributing to quality assurance and yield improvement during production. In this study, we attempted to detect defects inside a PEFC stack consisting of two layers of MEAs by using magnetic sensors. The magnetic field around the stack generated during power generation was measured, and the current distribution in the MEA was estimated by inverse problem analysis based on sparse modeling theory. As a result, the current distribution of each of the two stacked MEAs was obtained separately, and a 10 mm × 10 mm size defect located at both the center and the edge of the electrode was successfully identified, although some internal defects could not be detected. A certain defect could not be detected because of insufficient difference in magnetic fields between the defective and normal stacks. This suggests that the sensitivity of current magnetic sensors is insufficient to detect 10 mm x 10 mm defects at some internal locations.
OKUHIGASHI et al. (Wed,) studied this question.