Fraunhofer ISE has developed a flexible platform to accelerate the production of membrane electrode assemblies (MEAs) for fuel cells. The facility is now available to manufacturers as well as machine and plant builders to tinker with production processes.
In developing its platform, Fraunhofer ISE focused on innovative and continuous processes for constructing membrane electrode assemblies. This is because high throughput rates are essential for reducing the cost of manufacturing the core component for fuel cells in the future. The Fraunhofer facility’s production research takes into account the entire value chain, including quality control.
To put this into context: MEAs are the heart of every polymer electrolyte membrane (PEM) fuel cell, where the conversion from chemical to electrical energy takes place. From Fraunhofer ISE’s point of view, accelerated and automated production of this component is becoming increasingly important. This is because, according to the project team, “driven by demands for emission-free heavy-duty and commercial transport, truck manufacturers are currently making substantial investments in both battery-electric and fuel cell-electric systems.” “The expected production volume for the electrochemical heart of the fuel cell, the membrane electrode assembly (MEA), is 1.2 million m² of active MEA area per year for 20,000 trucks.” This amount is based on an assumed 30 m² of membrane and 60 m² of catalyst layer per vehicle.
According to those responsible, 25,000 to 35,000 square metres of catalyst-coated membrane are required per gigawatt of additional capacity for the ramp-up of electrolysis. “However, these quantities cannot be achieved with current manufacturing processes. For the expected market ramp-up, existing plant concepts must be adapted and scalable production methods have to be developed,” stated the researchers, outlining the current situation.
Production research at Fraunhofer ISE therefore takes an in-depth look at every step of the manufacturing process – from the treatment of the catalyst powder to the composition of the 7-layer MEA, which consists of a central membrane and two catalyst layers, reinforcement frames and gas diffusion layers. The influence of process design and parameters, materials and component architecture on the cost, quality and performance of the MEA is being investigated.
Right at the start of the value chain, Fraunhofer scientists are investigating various mixing processes for producing catalyst inks. They are also working on refining the membrane coating, the drying of the catalyst layer and the reinforcement frame, among other things. The Fraunhofer Institute considers the production of the catalyst layers, which are printed either on a transfer foil or directly onto the membrane, to be a key process step. In addition to the proven slot die process, its researchers can now also test rotary printing processes or indirect gravure printing thanks to interchangeable printing units.
The primary goal is and remains the necessary scalability. That is why Fraunhofer ISE is focusing primarily on continuous roll-to-roll processes. The specific target is a throughput speed of 10 metres per minute, a value that the industry can easily handle, according to the initiators.
The entire production chain is tested in industry-oriented pilot plants at Fraunhofer ISE’s hydrogen technology centre. “We are the only research institute in the world that will have industrial-scale production facilities, including microstructure analysis and characterization of MEAs in the test bench, which allows for rapid transfer from the laboratory to production,” commented Ulf Groos, Head of the Fuel Cell Department at Fraunhofer ISE. In addition to production research for fuel cell MEAs, the pilot plants can also be used for electrolysis MEAs (proton exchange membrane and anion exchange membrane).
Measurement technologies integrated into the plant also ensure inline quality control. “Despite the continuous process, we can track changes in the production process and their effects on later process steps or product quality. We develop a track & trace system that regularly marks and identifies the products,” explains project manager Linda Ney from Fraunhofer ISE. The MEAs processed on the pilot plant are also tested for performance in fuel cells under varying operating conditions.
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