At its site in Dortmund, Fraunhofer IWS has started operating a pilot plant that enables a key step in the process chain, the bipolar plate coating. The facility operates using a roll-to-roll (R2R) process equipped with vacuum coating chambers. Once fully implemented, it will be capable of coating band materials at speeds of several meters per minute using arc-based techniques. The engineers will present these developments to potential industry partners at the Hannover Messe in March 2025.

A Step Towards Industrial Scaling

“With innovations like these, we want to support the development of sustainable drive concepts for the mobility sector,” emphasizes Dr. Teja Roch, subproject leader at Fraunhofer IWS in Dortmund. “Our advancements mark a major step toward more economical and high-quality production of fuel cells. Germany can leverage this cutting-edge technology to establish new value chains, particularly for the automotive industry.”

Environmentally friendly propulsion technologies are essential for reducing emissions in the transport sector. According to the German Environment Agency, it is responsible for approximately 146 million tons of greenhouse gases (measured as CO₂ equivalents), accounting for about 22 percent of Germany’s total emissions. Transport-related emissions must be reduced to around 84 million tons of CO₂ by 2030 to meet the country's climate targets.

Vacuum Coating of Metal Bands in Roll-to-Roll Processing

The Fraunhofer Institutes IWU and IWS are developing modular components for production lines with further partners aimed at the rapid and cost-effective manufacturing of bipolar plates. The roll-to-roll system is modularly designed, enabling companies to select and integrate components based on their specific requirements. Future implementations will be supported by digital twins—virtual functional models that facilitate the development of individual modules across various locations and their integration into a complete system.

The development goal entails several coordinated process steps. A potential sequence could start with a coating system that unwinds a metal band approximately 100 micrometers thick, cleaning it as needed. The foil would then pass through specially designed vacuum chambers where physical vapor deposition (PVD) technology would first apply a corrosion protection layer, followed by a 100-nanometer-thick graphite coating.

The coated metal band could then be transferred to a forming system developed by Fraunhofer IWU. Structures essential for channeling gas flows in fuel cell stacks would be embossed onto the plates using roll forming. Subsequently, laser welding modules developed in Dresden would join two half-plates into complete bipolar plates, which high-speed laser systems would then separate into individual BPPs.

This integrated process sets a new international benchmark for bipolar plate manufacturing, replacing the conventional batch production of individual plates with a continuous roll-to-roll process. Key innovations include highly efficient and resource-conserving coating technology, advancements in laser welding techniques, high-speed laser cutting, and novel forming methods.

A team led by Fraunhofer engineer Maurizio Giorgio is already testing crucial parts of this process chain on a 14-meter-long pilot plant at Fraunhofer IWS in Dortmund. At Hannover Messe 2025, from March 31 to April 4, the institute will showcase a 1.6 by one meter model of this production line at Hall 13, Booth C41/1. Engineers will present the underlying innovations and inform potential industry users about application scenarios. By the end of the project, the partners aim to further refine the system, enhance its performance, integrate the individual modules within a digital twin, and prepare for industrial deployment.

Sources:

(1) Bundesumweltamt: Klimaschutz im Verkehr (German)
(2) Fraunhofer-Gesellschaft: Starting Signal for the Hydrogen Age in Freight Mobility