Technology & Innovation

HyReCo advances AEM electrolysis by combining innovative cell components with high‑rate manufacturing and an AI‑based digital twin. This page describes the key technology elements: bipolar (half) plates, porous transport layers, membranes and the digital twin & AI framework.

AEM Electrolysis in the Technology Landscape

Water electrolysis today is dominated by Alkaline water electrolysers and Proton Exchange Membrane electrolysers (PEMEC). AEM electrolysers aim to combine advantages of both: operation in alkaline environment with the potential to use non‑PGM catalysts and lower‑cost materials, while offering compact cell designs closer to PEM.

State‑of‑the‑art AEM cells and materials still face three major limitations:

  • lower hydroxide conductivity (OH⁻ mobility ≈ 50–57% of H⁺ for membranes of the same thickness as PEM),
  • poor chemical stability under highly alkaline conditions,
  • pronounced degradation of electrolyte and membrane at elevated temperatures.

HyReCo addresses these limitations through a holistic approach that links materials, component design, manufacturing and digitalisation.

Innovative Cell and Component Concepts

Bipolar (Half) Plates (BPP / BPP‑HP)

Bipolar (half) plates are key components for cost, performance and scalability. HyReCo investigates two main material families and associated high‑rate production routes:

  • Metallic plates (stretch‑forming steel + coating)
    • Use of stretch‑forming steel grades allowing higher forming degrees and more flexible flow field designs.
    • Substitution or optimisation of conventional nickel coatings by alternative corrosion‑resistant layers.
    • Evaluation of cold‑plating as a high‑speed, multi‑layer corrosion protection benchmark for cost reduction.
    • Targets: reduced plate thickness and material usage; continuous high‑rate production; robust corrosion resistance and electrical properties.
  • Graphite composite plates (ultra‑thin, hot‑pressed)
    • Development of ultra‑thin graphite‑based composite films (e.g. carbon fibres, thermoplastic, graphite or epoxy‑based systems) with Carbon ID.
    • Hot pressing of films into bipolar half plates with optimised flow fields.
    • Use of Fraunhofer IWU’s roll embossing technology to combine high design freedom and high‑rate capability.
    • Target: TRL 7 for the composite material by project end and a corrosion‑free alternative benchmarking against PEM graphite plates.

Both plate concepts are supported by CFD and FEA models to optimise flow distribution, pressure drop, mechanical and thermal behaviour and manufacturability.

Porous Transport Layers (PTL)

The porous transport layer is crucial for gas and water transport, electrical conduction and mechanical interface behaviour. HyReCo explores cost‑reduced but robust PTL solutions.

  • Ni foam vs. stainless steel (SS 316L)
    • Comparative testing of Ni foam and SS 316L under realistic AEM operating conditions.
    • Variation of PTL thickness and porosity to reduce raw material consumption.
    • Evaluation of gas/water transport, electrical conductivity, corrosion behaviour and durability.
  • High‑rate capable PTL designs
    • Cooperation with PTL suppliers (e.g. Haver & Boecker).
    • Identification of PTL geometries and materials compatible with roll‑to‑roll processes, forming and joining routes used in high‑volume production.

AEM Membranes and CCMs

The membrane is the central performance and lifetime driver in AEM electrolysers. HyReCo analyses state‑of‑the‑art membranes and develops improved concepts.

Initial focus is on commercial membranes such as EVONIK DURAION®, fumasep FAAM‑20 and FAAM‑PK‑75 (Fumatech) and membranes from Chemours.

  • Accelerated ageing tests:
    • Alkaline resistance (e.g. concentrated KOH at 80 °C, 7 and 30 days).
    • Climate and humidity cycling (e.g. PV 2005 protocols).
  • Follow‑up analyses:
    • mass change,
    • SEM cross‑sections (delamination, cracking),
    • dynamic mechanical analysis (change in modulus),
    • ion exchange capacity (decrease in ion‑conducting groups).
  • Development of material and transport models for hydroxide conduction and degradation behaviour.
  • Derivation of manufacturing requirements and concepts for PGM‑reduced CCMs, building on results from projects like “105°scaled”.

Digital Twin & AI as Innovation Drivers

From High‑Fidelity Models to Reduced‑Order Models

HyReCo builds a modelling chain that links detailed physics‑based simulations to fast, digital‑twin‑ready models:

  • High‑fidelity models
    • CFD for flow fields and gas/liquid transport.
    • FEA for structural and thermal analysis of plates, end plates and seals.
    • Electrochemical models for reaction kinetics and mass transport.
  • Material and degradation models
    • Parameterised models linking corrosion resistance, conductivity and mechanical strength to performance and degradation.
    • Component focus: end plates, BPP/BPP‑HP, PTL, gaskets, membranes and internal flow paths.
  • Reduced‑order models (ROMs)
    • Extraction of key dynamics from high‑fidelity simulations.
    • Real‑time capable models for integration into control and monitoring systems and for virtual experiments.

AI and Invertible Neural Networks (INNs)

To accelerate simulations and enable advanced monitoring, HyReCo employs AI‑based surrogate models, including Invertible Neural Networks.

  • Data sources
    • High‑fidelity simulations covering a wide range of designs, materials and operating conditions.
    • Experimental data from the HyReCo single cell, 10‑cell stack and reference AEM systems.
  • Modelling tasks
    • Forward direction: prediction of cell/stack voltage, efficiency and degradation indicators.
    • Backward direction: estimation of internal, non‑measured states (“virtual sensors”) from limited sensor data.
  • Applications
    • Fast design space exploration (new membranes, new plate geometries).
    • Predictive operation and maintenance planning.
    • Long‑term scenario analyses under realistic and unfavourable operating conditions.

Life Cycle Assessment and Life Cycle Costing

Innovation in HyReCo also covers sustainability and economics. LCA and LCC are integrated directly into the technology development.

  • LCA
    • Environmental footprint from raw materials via manufacturing and operation to end‑of‑life.
    • Identification of carbon and resource hotspots, e.g. coatings, composite processes, membranes.
  • LCC
    • Total cost of ownership for the AEM cell and key components.
    • Quantification of cost reduction from high‑rate production, material substitutions and extended lifetime.
  • Results feed back into material and design choices, process development and scale‑up strategies.

Demonstration and Technology Readiness

HyReCo’s technology package is demonstrated in a laboratory single cell and a 10‑cell HyReCo AEM stack:

  • Single cell
    • Flexible platform for rapid component testing and detailed diagnostics.
    • Provides high‑quality data for model and digital twin validation.
  • 10‑cell demonstrator stack
    • Integrates optimised BPP, PTL, membranes, seals and end plates with high‑rate capable processes.
    • Instrumented for digital twin integration and long‑term experiments.

By project end, HyReCo aims for TRL 5 for the cost‑optimised AEM cell and 10‑cell stack, TRL 7 for the ultra‑thin graphite composite material and hot‑pressing approach, and a validated, modular digital twin framework transferable to other electrolyser and fuel cell technologies.