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Fuel cell performance and durability depend strongly on internal water management. Researchers at University of Tsukuba have developed a faster method for assessing fuel cell conditions by simplifying electrochemical impedance spectroscopy (EIS). By narrowing the frequency range and reducing the number of measurement points, the method substantially reduces measurement time while maintaining useful diagnostic accuracy. Integrated with automated operational control, it enables membrane dry-out to be detected and mitigated through adjustments to operating conditions. These findings could advance the development of practical diagnostic and control technologies for fuel cell systems.

Tsukuba, Japan—Proton-exchange membrane fuel cells (PEMFCs) are a clean power-generation technology that produces no direct carbon dioxide emissions during operation. Their performance and durability depend strongly on effective water management. Monitoring internal conditions during operation is essential to prevent flooding, in which excess liquid water accumulates within the cell, and membrane dry-out, in which the electrolyte membrane loses moisture. Electrochemical impedance spectroscopy (EIS) is a widely used diagnostic technique that characterizes the cell's electrochemical response by applying a small alternating-current signal over a range of frequencies. However, conventional EIS measurements typically involve sequential measurements across a broad frequency range and can take several tens of seconds or longer to complete. This limits their suitability for monitoring rapidly changing operating conditions.

In this study, the researchers reduced both the frequency range and the number of measurement points required for diagnosis. The proposed method uses only six measurement frequencies, compared with 41 in conventional EIS. Comparisons with conventional EIS results showed that a carefully balanced selection of frequencies that capture changes in impedance improved diagnostic accuracy relative to conventional frequency-selection approaches.

The researchers also developed an integrated program combining impedance measurement, data analysis, and operational control. Using resistance parameters derived from impedance data as indicators of the cell's internal condition, the program automatically adjusted operating conditions. This approach enabled the detection and mitigation of electrolyte membrane dry-out and insufficient air supply within the cell.

The proposed method could enable near-real-time diagnosis and control of fuel cell operating conditions without substantially increasing system complexity. Future work will focus on further reducing measurement time and optimizing frequency selection to advance practical diagnostic and control technologies for fuel cell systems.

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This research was conducted under a joint research agreement between the University of Tsukuba and HIOKI E.E. CORPORATION. The ALDAS impedance measurement system used in this research was provided free of charge by HIOKI E.E. CORPORATION.

Original Paper

Title of original paper:

Real-Time PEMFC Diagnosis Using Electrochemical Impedance Spectroscopy Under Limited Data Conditions

Journal:

International Journal of Hydrogen Energy

DOI:

10.1016/j.ijhydene.2026.157623

Correspondence

Assistant Professor AKIMOTO Yutaro
Institute of Systems and Information Engineering, University of Tsukuba

Related Link

Institute of Systems and Information Engineering