Study on the influence factors of gravimetric hydrogen storage density of type III cryo-compressed hydrogen storage vessel

Cryo-compressed hydrogen storage is a high-density hydrogen storage method, with volumetric hydrogen storage density determined by temperature and pressure. However, the gravimetric hydrogen storage density is influenced by vessel volume, insulation method, operating pressure, operating temperature, and vessel structural dimensions. This study investigates the variations in gravimetric hydrogen storage density under different influencing factors based on the design methods for the liner, winding layers, and insulation layers of cryo-compressed hydrogen storage vessels. The research findings indicate that the optimal pressure must be determined based on the vessel volume. For small-volume vessels, the hydrogen storage density remains relatively unchanged once the pressure reaches 40 MPa, while for large-volume vessels, the best performance occurs at pressures between 20 and 30 MPa. Additionally, vessels with a smaller length-to-diameter ratio and a semicircular dome cross-section exhibit superior hydrogen storage performance. Larger volumes and lower operating temperatures favor the increase of hydrogen storage density. Finally, the study analyzes future process improvements to further explore ideal scales and structures that can achieve the DOE's targets and enhance the economic efficiency of hydrogen transportation.