56 printing technology is that it does not need tight integration with the material supplier. “We can be somewhat independent of the type of material, but it helps a lot if there are discussions on batch variation – we can print the majority of materials we get, but some need engagement with the supplier; for example, if there is foaming or certain dilutions or stabilisation agents that are needed for particle loading,” said Hartkopp. “We need around a litre for the analysis in a couple of days, and implement in less than a week if necessary – that gives the custom a lot more confidence.” At the moment, the system uses one material per print head, but research is continuing on the next-generation system that could be able to handle multiple materials per print head, says Hartkopp. Electrolyser The low hydrogen permeation coefficient of only 3–4 E-8 cm²/s means customised, tough polyurethane adhesives are also suitable for various components involved in the hydrogen production process. Alkaline electrolysers need adhesive systems with even higher chemical resistance than is afforded by polymer membrane technology because this widely used type of electrolyser works with an aqueous potassium hydroxide solution (30–35% KOH) at 90–95 C as its electrolyte. The majority of organic adhesive and sealing systems are not able to withstand such conditions permanently. A specially optimised, highly cross-linked and chemicalresistant epoxy resin, which in its thixotropic form is suitable for applying adhesive beads, is one of only a few products currently available capable of meeting these requirements. Automated production of an electrolyser stack with capacity of 1 MW is around six times faster than manual assembly. However, the task of sealing the bipolar plates, the individual cells and the stack as a whole poses a major challenge. If complete or partial automation is to be achieved, the flat gaskets and O-rings often used must be replaced with an alternative sealing method, says Andreas Arlt, business development manager at Wevo Chemie. Wevo has developed materials that can be applied as liquid sealants and adhesives. These bring three key benefits: a high degree of chemical resistance, low hydrogen permeation and good adhesion properties. All three have been verified by leading research institutes and in customer projects. Polyurethanes, epoxy resins and silicones from Wevo open up new possibilities for alkaline and Anion Exchange Membrane (AEM) as well as PEM electrolysers, as in the design of stacks, for example. In alkaline electrolysis systems, the hot potassium hydroxide solution (30–35% aqueous KOH solution at a temperature of 80–90 C) used as the electrolyte creates challenging ambient conditions. Newly developed materials, based on modified polyurethanes, epoxy resins and silicones, enable sealing, stack design and automated production for this technology. The materials are also increasingly being used for AEM electrolysers, where the requirements are high despite the much lower concentration of the KOH solution. The new epoxy resin system can be used as an adhesive and sealing material for bipolar plates, individual stack cells and the entire stack with high chemical resistance. This has been confirmed by immersing test specimens in a 35% aqueous KOH solution at 90 C for several weeks, and by investigations carried out by the Welding and Joining January/February 2026 | E-Mobility Engineering An open inkjet printer for r&d (Image: Quantica)
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