Strong under pressure

REHAU’s pioneering development

Gasoline and diesel fuel sources won’t suddenly dry up from one day to the next. There are also other kinds of engines – electric motors for example, increasingly finding their way on to the market. Still, for long distance driving, viable energy sources capable of competing with fossil fuels are what’s proving rare.

One promising alternative is hydrogen, which is transformed into electricity in a fuel cell. To be able to use hydrogen as fuel in cars, special tank systems capable of meeting extremely high security and usability standards are required. For a good three years REHAU experts have been dedicating their full attention to the development of just such a tank system. Today, REHAU’s Type Class 4 hydrogen pressure tank has proven in the final test to be extremely safe, quite robust, and most importantly, an excellent resource-optimised alternative to currently available conventional tank systems.

The tank stores hydrogen at 700 bar. For the sake of comparison: these are the same pressure conditions occuring in the deep sea at a good 7000 metres below the ocean’s surface. The pressure tank has to be built to ensure that not a trace of hydrogen accidentally escapes, and it also has to be able to withstand the severest of crash situations. Each single tank system component was especially developed to meet these challenges.

The tank’s innermost layer has to ensure that no gas escapes. No internal hydrogen can penetrate outwards; nothing external can penetrate the interior. The capsule has to remain sealed, which places extreme demands on the material used. Cross-linked polyethylene, an extremely robust, highly shock-resistant thermoplastic polymer that serves, for instance, in piping for gas and water supply systems, presents itself here as the essential component. This high-performance material is pressure-blasted into its cylindrical form in a special production facility.

That innermost layer is then covered with a sort of cocoon of carbon fibres. The cocoon serves to buffer against the stresses of the intense internal pressure, as well as protecting the tank from any external forces. Because of the high-quality carbon fibres, this particular layer is of decisive significance in the cost-efficiency of the tank system. Here, REHAU developers selected a procedure that lends the cocoon maximal strength using only a minimum of materials. An ecologically attractive, economically intelligent solution that’s sure to play a meaningful role in the hydrogen cars of the future.

The interest generated by REHAU’s pioneering development, for which an investment in the neighborhood of seven-figures was designated, has rightfully registered considerable appeal.

Further information

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