Development of a Hydrogen Aging Test Apparatus for the Liner of Vehicle-Mounted Type IV Hydrogen Storage Cylinders
This study addresses the critical lack of validated test apparatus for evaluating hydrogen-induced aging in polymer liners of Type IV hydrogen storage cylinders under extreme service conditions. A novel hydrogen aging test apparatus, independently developed by the China Special Equipment Inspection and Research Institute, is presented. The apparatus integrates a high-pressure hydrogen aging vessel, an explosion-proof environmental chamber, a regulation and control system, and a software control system, enabling tests at pressures up to 87.5 MPa and temperatures from -40 to 100 °C. The reliability of the apparatus was verified through a 1000-hour hydrogen aging test on high-density polyethylene (HDPE) liner material at 85 °C and 87.5 MPa (1.25 times nominal working pressure). Post-aging characterization included hydrogen permeation tests and mechanical tensile tests. Results indicate a slight degradation in hydrogen barrier performance: the hydrogen permeation coefficient (Pe) increased by 4.76%, the diffusion coefficient (D) decreased by 3.08%, and the solubility coefficient (S) increased by 8.10%. Conversely, mechanical properties showed minor improvements: average tensile strength increased by 6.51% and nominal elongation at break increased by 15.33%. These findings provide essential empirical data for the selection, development, and improvement of liner materials for 70 MPa Type IV hydrogen storage cylinders, supporting the advancement of China's hydrogen energy infrastructure.