Hydrogen-powered fuel cell vehicles are still rare and expensive. In addition to efficiency problems, this is partly due to a core component, the gold-coated bipolar plates (BiP). They are also expensive to manufacture. The Fraunhofer Institute for Material and Beam Technology IWS Dresden, the German automotive group Daimler and the Finnish steel company Outokumpu Nirosta have now developed an inexpensive alternative for rapid mass production.
Instead of using gold as an electrically conductive coating, the thin steel sheets are coated with a wafer-thin layer of carbon using physical vapor deposition (PVD). In this process, an electric arc in a vacuum chamber first vaporizes the carbon, which is then deposited on the stainless steel in a highly pure, uniform and very thin layer. This carbon layer has a similarly low contact resistance to gold. As the carbon layer is very thin, the coating itself only takes seconds, which makes the process very economical. In addition, the innovative Fraunhofer technology also promises a higher production speed. Another advantage is that entire rolls of sheet metal can be coated before forming, as the Fraunhofer coating is so durable that it can withstand the forming and welding process. The concept is suitable for mass production and can significantly reduce manufacturing costs. It also makes an important contribution to the construction of environmentally friendly vehicles.
