52 January/February 2026 | E-Mobility Engineering Developing adhesives and sealing materials appropriate for hydrogen-based fuel cells and electrolysers is a sticky challenge. Nick Flaherty investigates Getting stuck in Hydrogen is the smallest of all molecules, meaning that the adhesives and sealants used for fuel cells must ensure a very tight seal to prevent diffusion. The materials also need to survive for as long as possible in highly acidic (low pH) environments. Fuel cells consist of several functional layers that can differ both in terms of the materials and components used and in terms of the working principle. One of the most common types, which is currently being widely researched because of its suitability for the automotive sector, is the Proton Exchange Membrane (PEM) fuel cell. The bipolar plates of the PEM fuel cell ensure a steady supply of hydrogen to the cells and simultaneously control the release of electrical energy, but because hydrogen is flammable and can form explosive mixtures (oxyhydrogen) in an oxygen-containing atmosphere, reliable sealing of the individual cells is essential. The sealing materials must be not only highly impermeable to gas but also resistant to challenging conditions such as continuous high temperatures of up to 120 C or acidic environments from the hydrogen. If the bipolar plates have tolerances due to manufacturing, the resulting uneven pressure distribution on the sealing materials must be compensated, especially while the stacks are being pressed. To date, preformed inlay gaskets have been used for this compensation. However, owing to the need to insert them manually on both sides of each bipolar plate, they are unsuitable for automated production in high volumes, as required in automotive fuel cell design in particular. There is also a risk that a bipolar plate might become detached during stacking and no longer seal effectively. Commercially available, addition-curing silicone liquid gaskets have drawbacks, such as their generally high gas permeability and their poor adhesion to most substrates. Instead, a chemically resistant, two-component material based on polyurethane and silicone can be applied as a liquid gasket that is formed inplace. This has advantages for the manufacture and operation of fuel cell components. One of the silicone-based products exhibited a very low hydrogen permeation coefficient of about 130 E-8 cm²/s after A fuel cell stack under test (Image: Wevo Chemie)
RkJQdWJsaXNoZXIy MjI2Mzk4