“The special suitability of our materials for an application sets us apart from the competition,” said Dr. Alexander Hähnel. Jürgen Emig, his colleague on “Team Hydrogen” from Technology & Innovation (T & I), adds: “Material competency is the top priority when it comes to hydrogen, across all applications and along the value chain, from electrolysis to the fuel cell.”
From the standpoint of material development, what needs to be done in the field of hydrogen for the future? For example, for reasons relating to safety and efficiency, it is essential to keep hydrogen molecules – which are very small – from penetrating sealing materials (the technical term is permeation) and becoming volatile. In return, sealing materials must not impair fuel cell or electrolyzer processes by releasing harmful substances. Depending on the application, seals must also resist drastic changes in pressure and temperature, not to mention corrosive alkali solutions or high acid concentrations that accelerate the aging process.
No Standards Thus Far
The existing standard solutions only rarely suffice. New sealing materials and designs must generally be devised for hydrogen applications. At a minimum, it is necessary to systematically check current materials against the application’s requirements, especially with regard to longevity. This is complicated by the fact that the various electrolysis and fuel cell technologies exist in parallel, and standards have not yet been established in any of them. Approaches and designs vary from manufacturer to manufacturer. So many issues are in flux in this key sector for the future.
Nonetheless, FST is achieving remarkable successes in material development. 35 FCPO 100 is an in-house development resembling liquid silicone during processing. Employees at FST’s corporate sibling, Freudenberg e-Power Systems, use it in their low-temperature PEM fuel cells. 70 FKM 256261 is a material that FST developed specifically to meet the demands of PEM electrolysis and high-temperature PEM fuel cells. It recently completed a successful series launch.
More Than 2 Million Euros for Test Equipment
“For hydrogen, we need shorter development times than we are used to for the auto industry,” Hähnel stressed. Powerful test options in labs and test facilities are an important component of accelerated development work. “We will have invested more than 2 million euros in this area by year’s end,” Emig said. Among other things, this will lead to more practical insights on the impact of electricity and media such as oxygen on seals. “We also want to understand the entire cell,” Emig said. FST will be able to test four cells in parallel on a new test stand. The company is also working on tests for complete fuel cells and electrolysis stacks. Here it is cooperating with customers and highly respected institutes such as Fraunhofer and the Center for Solar Energy and Hydrogen Research Baden-Württemberg (ZSW).
“We want to understand the entire cell.”
Seals often have to take on extra functions in hydrogen applications. The material combinations, such as rubber attached to a carrier part, make the development work even more complicated. High-performance plastics are often involved as well. Plug & Seal connectors equipped with sensors are one example of functional integration. Another example: seals with bipolar plates or cell frames. With their special designs, they perform some of the media routing, in addition to sealing. The overarching goal is to simplify the assembly of fuel cells and electrolyzers for manufacturers while reducing their costs.
In every aspect of hydrogen-related development work, the concept of “‘Innovating Together’ is a great help. It is playing an important role at Lead Centers, the divisions and Technology & Innovation (T & I),” Emig said.
