Diagnostic system measures wear in electrolyzers and fuel cells during operation 

Researchers at Fraunhofer IFAM have advanced a diagnostic method for electrolysers and fuel cells. Dynamic impedance spectroscopy now delivers readings straight from live operation, at currents up to 30 amps. The technique flags early wear such as membrane damage or electrode corrosion, paving the way for predictive maintenance. 

Electrolysers and fuel cells operate under constantly shifting conditions. Variable renewable power feed-in accelerates wear on these systems. Conventional impedance spectroscopy requires a steady-state condition, meaning operation has to pause for each reading. That leaves the real, fluctuating day-to-day operation largely unmeasured. 

Fraunhofer IFAM has refined the method to capture data directly from the running process. The new setup handles considerably higher current levels than the previous lab configuration. A small multi-frequency signal is superimposed on the normal operating current. From the resulting current and voltage response, researchers calculate the complex impedance — the frequency-dependent electrical resistance of the system. 

Frequency Signatures Separate Aging Mechanisms 

Impedance readings reveal what's happening inside an electrochemical system. Electrode reactions, ion transport through the membrane, electrical contact resistance and mass transport each show up at different frequencies. The method isolates these processes and evaluates them individually, revealing the real-time condition of components such as the membrane or electrodes. 

Tracking spectra over time indicates the system's state and aging progress: a rising resistance component points to deteriorating electrode reactions, corrosion or weakening contacts. Shifts in phase behavior signal membrane wear, water-balance issues or restricted mass transport. The method pinpoints whether performance losses stem from materials, interfaces, contacts or operating conditions. 

Forecasting Maintenance Windows 

A real-time diagnostic system continuously tracks cell condition and catches early-stage changes before they cause performance loss or failure. It supports precise condition assessment, targeted fault diagnosis and predictive maintenance planning. 

The team has scaled the method from lab conditions to real-world application: the measurement signal now overlays operating currents up to 30 amps. Integrated online data processing calculates impedance trends over time and displays them directly. AI-based models extend the results further, accounting for changing environmental conditions such as pressure and temperature swings, as well as new material compositions. 

Built for Plant Control Integration 

The system integrates directly into plant control, for instance an energy management system. Operators of PEM fuel cells and alkaline electrolyzers gain continuous condition data reflecting the plant's health status. This allows early detection of critical processes such as catalyst degradation, forward-looking maintenance scheduling and adjusted operating strategies to minimize degradation. 

(Source: Fraunhofer-Institut für Fertigungstechnik und Angewandte Materialforschung IFAM/2026)