Introduction
Efficient and durable PEM electrolysis is a key building block for producing green hydrogen at scale in Europe. Within the CLEANHYPRO project, Fraunhofer ISE contributes its expertise in state-of-the-art electrochemical characterization – from individual materials to full short stacks under realistic operating conditions. This helps partners to understand what really limits performance and lifetime, and how to optimize components and designs faster.
From Material Screening to Optimized MEAs
At the material and membrane electrode assemblies (MEA) level, we use 4 cm² laboratory cells to perform in-situ characterization of MEAs for PEM water electrolysis.
Our in-house developed portfolio of test cells is optimized for different research questions and allows:
• Fast, high-throughput screening of many MEA combinations
• Easy handling thanks to flexible cell design
• Fully automated, parallel test benches for pressureless operation
The results can be transferred directly into MEA production research and into the design of larger cell formats and pressurized operation. We can also quickly adapt cell designs to investigate other components such as porous transport layers or coatings for bipolar plates, enabling fast and cost-effective screening campaigns with reliable and reproducible data.
In-Depth In-Situ Studies Under Realistic Conditions
For more complex investigations in PEM water electrolysis, we work with 25 cm² laboratory cells on pressure-resistant single-cell test benches. These systems support:
• Differential pressures up to 50 bar
• Temperatures up to 120 °C
• Electrochemical stress protocols up to 1000 A
Standard methods such as polarization curves (IV) and electrochemical impedance spectroscopy (EIS) are available on all test units. To complement the electrochemical data, we offer product gas analysis (H₂ in O₂) using thermal conductivity detection and gas chromatography, and water analysis via ICP mass spectrometry and ion chromatography.
Short Stack Testing – Bridging the Gap to Application
To bridge the gap between single-cell research and real-world systems, we perform comprehensive in-situ characterization of short stacks for PEM water electrolysis. Our institute’s short stack test bench supports:
• Currents up to 1500 A
• Voltages up to 25 V
• Pressures up to 50 bar
• Operating temperatures up to 80 °C
• An internal cooling capacity of 15 kW
These capabilities allow fully automated testing over wide parameter ranges, including differential pressures, temperatures and electrochemical ageing protocols. Again, product gas analysis and water analysis are available to complement the electrochemical measurements.
Within CLEANHYPRO, electrochemical impedance spectroscopy (EIS) at short-stack level was implemented. This represents an important innovation for stack characterization, enabling the identification of different voltage loss mechanisms in each individual cell and providing new insights into limiting phenomena and degradation mechanisms at stack level.
Accelerating Innovation in CLEANHYPRO
Within CLEANHYPRO, these characterization tools and methods provide a solid experimental basis for:
• Understanding performance and degradation mechanisms
• Guiding the design of advanced materials and MEA production
• Reducing the risk when scaling up to larger cells and stacks
By combining flexible test hardware, advanced analytics and many years of experience, Fraunhofer ISE helps the CleanHyPro consortium push PEM electrolysis technology closer to industrial deployment.
Conclusion
Fraunhofer ISE contributes advanced measurement and testing capabilities to the CLEANHYPRO project to characterize materials, single cells and short stacks for PEM water electrolysis under realistic conditions. Using 4 cm² and 25 cm² laboratory cells as well as a short-stacks, Fraunhofer ISE investigates performance and degradation mechanisms with electrochemical methods (e.g. IV-curves, EIS), gas analysis and water analysis. The resulting data help project partners to optimize MEAs and cell components to reduce risks when scaling up to larger cells and stacks.
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