LIQUID HYDROGEN STORAGE, SERIES PRODUCTION Summary

Liquid hydrogen takes up less storage volume than gas but requires cryogenic vessels. State-of-the-art applications for passenger vehicles consist of double-wall cylindrical tanks with a hydrogen storage mass of up to 10 kg. The preferred shell material for the tanks is stainless steel, since it is very resistant to hydrogen brittleness and shows negligible hydrogen permeation. Therefore, the weight of the whole tank system including valves and heat exchanger is more than 100 kg. The cavity between the inner and outer vessel is mainly used for thermal super-insulation. The remaining heat in-leak leads to a boil-off rate of 1 to 5 percent per day. Car storage systems require a fail-safe design since drivers are usually not experienced in handling hydrogen. Therefore, Failure Mode and Effect Analysis (FMEA) performed on critical components shall minimize the occurrence of malfunctions of the system. The production of several liquid hydrogen tanks which fulfill the draft of regulations of the European Integrated Hydrogen Project (EIHP) is being prepared. Cars represent the ultimate market for manufacturers of hydrogen storage systems due to the quantities involved worldwide. They also pose some of the greatest challenges to commercialization, including their relatively small size, the vast fuelling infrastructure required, and the inconsistent maintenance habits of the public at large. In addition, performance and reliability expectations are high. Cost issues will be addressed by selecting automated production technologies and scaling effects in mass production.