As the hydrogen economy gains momentum in the global decarbonisation strategy, attention often centres on high-profile innovations like fuel cells, electrolysers and hydrogen-powered vehicles. One reason for the relatively slow progression of hydrogen-based technologies is the presence of new technical hurdles that need to be addressed.
Some often-overlooked components on the way to an efficient, safe, and reliable use of hydrogen are the sealings. They play a critical role in enabling the broad operation of hydrogen systems across the value chain. Freudenberg Sealing Technologies provides solutions that meet these technical demands and help pave the road towards a hydrogen economy.
The role of sealing technologies in the hydrogen economy
Sealing technologies are indispensable at every stage of the hydrogen value chain. Electrolysers, the basis of green hydrogen production, require seals that can withstand high pressures and chemically reactive environments. Without effective seals, gas leakage could undermine safety and efficiency, especially in systems with high operating pressures.
Similarly, storage and distribution systems depend on seals to safely manage hydrogen in high-pressure tanks, pipelines, and transport systems. Finally, applications like fuel cells and hydrogen combustion engines rely on advanced seals to ensure system efficiency and prevent failures under extreme thermal and mechanical stress.
Addressing unique challenges in hydrogen systems
Hydrogen presents a new level of challenges for engineers and materials scientists, often not only pushing existing technology to its limits but surpassing those boundaries many times over. One of the primary requirements is high-pressure resistance, often exceeding 700 bar.
What poses no problem for existing technologies like hydraulics becomes a significant challenge with hydrogen due to a phenomenon called embrittlement, caused by hydrogen’s small molecular size. This can lead to material degradation over time, especially in metallic and polymeric components.
Hydrogen’s chemical reactivity adds another layer of complexity: Effective seals must exhibit exceptional resistance to permeation and chemical degradation. Moreover, systems such as fuel cells and storage tanks experience wide temperature fluctuations.
Seals must perform reliably under these extremes, ranging from sub-zero temperatures during cryogenic storage to high heat in operating fuel cells. To address these issues and guarantee long-term durability, new sealing materials are needed.
For polymer membrane electrolysis, materials that promise a long service life of over 50,000 operating hours are already available. (Source: Freudenberg Sealing Technologies)
Material science at the core of innovation
Freudenberg Sealing Technologies has developed special elastomers and polymers that meet the demands of hydrogen applications. Materials such as hydrogenated nitrile butadiene rubber (HNBR) and fluoroelastomers (FKM) offer unique properties by themselves.
However, what makes these materials particularly effective in hydrogen environments are the proprietary additives developed by Freudenberg Sealing Technologies. These additives enhance the materials’ resistance to hydrogen embrittlement and chemical degradation, addressing challenges that standard HNBR and FKM cannot solve alone.
Freudenberg Sealing Technologies’ unique capabilities in engineering and testing new materials allow for tailored solutions that meet the requirements of hydrogen applications. The development of custom formulations not only enhances performance but also supports sustainability by extending the lifespan of seals and minimising waste.
Real-world applications of advanced seals
Freudenberg Sealing Technologies’ sealing solutions are already enabling key advancements in the hydrogen economy. In hydrogen mobility, seals are critical to the reliable operation of hydrogen-powered vehicles, including buses, trucks, and passenger cars.
Hydrogen refuelling stations also benefit from high-performance seals. Rapid refuelling at high pressures requires seals that can handle dynamic loading while maintaining safety. FTS’s solutions ensure reliable operation, enabling faster and more efficient refuelling processes.
Green hydrogen production represents another pivotal area for sealing technologies. Electrolysers equipped with advanced seals enable the safe and efficient generation of renewable hydrogen. By preventing gas leakage and maintaining system integrity, these seals optimise the performance and reliability of electrolysis systems, further supporting the development of downstream technologies.
Bipolar plates, a critical component in both fuel cells and electrolysers, directly benefit from the advancements in sealing materials and methodologies. The transition from advanced development to application showcases the interconnectedness of the hydrogen value chain, where innovations in one area drive progress across the entire ecosystem.
Collaborating to advance bipolar plate technologies
The phrase “thinking about seals early in the process” underlines the importance of considering sealing solutions early in the design process of bipolar plates. German machinery manufacturer Graebener, with two decades of experience in production technologies for bipolar plates, has partnered with Freudenberg Sealing Technologies to tackle the challenges in this critical area.
In a whitepaper by Graebener Bipolar Plate Technologies, Freudenberg Sealing Technologies experts Jürgen Emig, Director Pre-Product Development Hydrogen Applications, and Dr. Dominik Kraus, Head of Stamping Technology, emphasise the pivotal role of seals in the production process.
They advocate for integrating sealing considerations before finalising the design of the plates. Emig explained, “The topic of seals has often been underestimated so far – as has the fact that standard catalogue parts can only be used to a limited extent. It is very important to us that customers involve us before they invest in tooling for the plates.”
”When the carrier material, bonding agent and rubber are perfectly matching with one another, the sealing function is optimised.” – Dr. Alexander Hähnel, Freudenberg Sealing Technologies Material Specialist. (Source: Freudenberg Sealing Technologies)
Designing robust seals for bipolar plates requires customised solutions. Freudenberg Sealing Technologies’ materials, such as the proprietary 35 FCPO 100 and 70 FKM 256261, are tailored to meet the demands of proton exchange membrane (PEM) electrolysers and high-temperature fuel cells. Although silicone might be a common starting material, it falls short in terms of durability and high-temperature resistance.
The lack of standardisation in bipolar plate designs further complicates the process. According to Kraus, “With regard to plate design, the market is currently barely standardised.” Emig added that standardising design features could simplify the sealing process and accelerate production. Such advancements could lead to higher production volumes at lower costs, significantly benefiting the hydrogen economy.
Enabling the scale-up of the hydrogen economy
Seals, although small, have a significant impact on the hydrogen economy. By enhancing safety, they mitigate the risks of leaks and system failures, which are crucial in high-pressure and high-stakes applications. Efficient sealing solutions reduce energy losses and improve overall system performance, contributing to the viability of hydrogen technologies.
Durability is another key factor. Long-lasting seals lower maintenance costs and minimise downtime, making hydrogen systems more attractive for widespread implementation. This reliability is essential as the hydrogen economy scales to meet growing energy demands worldwide.
Conclusion
Advanced sealing technologies form the hidden backbone of hydrogen infrastructure. They enable the safe, efficient, and reliable operation of systems across production, storage, distribution, and application.
Freudenberg Sealing Technologies is at the forefront of this field, delivering solutions that address the technical challenges of hydrogen systems. To learn more about sealing innovations, visit https://www.fst.com/hydrogen/.
