As reported in the German media, researchers from the Materials Laboratory for Renewable Energies in Lausanne (EPFL) have succeeded in developing a "hydrogen filling station" with only the size of a washing machine. What began as a makeshift solution for storing hydrogen - there was only limited space in the laboratories for large gas pressure storage tanks - could ultimately be the solution for a decentralized hydrogen filling station network.
The device itself contains an electrolyzer, which provides hydrogen from chemical splitting of water. The device can store up to five kilograms of hydrogen, which corresponds to one tank filling of today's hydrogen-powered series vehicles. The filling station does not require the normally required pressure of 1000 bar. Even cooling of minus 200 degrees is not necessary. Instead, the researchers have designed a new metal hydride that absorbs the H2 molecules.
The researchers were faced with further challenges when it came to refueling a vehicle. For this purpose they developed a simple but ingenious solution to compress the hydrogen to the required 700 bar. For example, the hydrogen is heated via a heat exchanger. The "dance of the molecules" caused by the heat causes the pressure to rise and the gas is driven out of the storage tank. Today, a pressure of 200 bar can already be generated in this way. With the help of higher temperatures, the necessary pressure of 700 bar should be easy to achieve.
The prototypes of the mini-H2 filling station are scheduled for completion by the end of 2020. At the same time, the EPFL offshoot is working with Hyundai to develop a larger storage tank for hydrogen trucks. If all tests go according to plan, commercial production could start in summer 2021, says Andreas Züttel, director of the materials laboratory.