An Ageing Test Standards Analysis on Thermoplastic Liners of Type IV Composite Hydrogen Storage Tanks

Abstract

The liner of a carbon fiber fully reinforced composite tank with thermoplastic liner (type IV) works in a hydrogen environment with varying temperature and pressure profiles. The ageing performance of the thermoplastic liner may affect hydrogen permeability and the consequent storage capacity, degrade the mechanical properties, and even increase the leakage risks of type IV tanks. In this paper, both testing procedures and evaluation parameters of an ageing test in a hydrogen environment required in several standards are compared and analyzed. Hydrogen static exposure in a high-temperature condition with a constant temperature and pressure is suggested to be a reasonable way to accelerate the ageing reaction of thermoplastic materials. A total of 192 h is considered a superior ageing test duration to balance the test economy and safety. The ageing test temperature in the high-temperature condition is suggested as no lower than 85 °C, while the upper limit of test pressure is suggested to be 1.25 NWP. In addition, the hydrogen permeation coefficient and mechanical properties are recognized as important parameters in ageing performance evaluation. Considering the actual service conditions, the influence of temperature/pressure cycling, depressurization rate, and humidity on the ageing performance of thermoplastics in hydrogen are advised to be investigated experimentally.

Hydrogen Permeability of Polyamide 6 Used as Liner Material for Type IV On-Board Hydrogen Storage Cylinders

“…where P e is the gas permeability coefficient of the material (cm 3 •cm/(cm 2 •s•Pa)), ∆p/∆t is the arithmetic mean of the change of gas pressure on the low pressure side per unit time when it is stable permeation (Pa/s), V is the volume of the low pressure chamber (cm 3 ), s is the test area of the sample (cm 2 ), T 0 and P 0 are the temperature (273.15 K) and the pressure (1.0133 × 10 5 Pa) under the standard conditions, T is the test temperature (K), d is the thickness of the sample (cm), and p 1 − p 2 is the pressure difference between the two sides of the sample (Pa).…”

“…Currently, on-board hydrogen storage cylinders primarily consist of two types: type III and type IV. Of these, the type IV hydrogen storage cylinder has gained global attention due to its remarkable attributes, such as high hydrogen storage density, lightweight construction, and cost-effectiveness [ 3 , 4 , 5 ]. Internationally, nylon and high-density polyethylene are the predominant liner materials employed in type IV hydrogen storage cylinders.…”

“…Hydrogen permeability coefficient P e (cm3 •cm/(cm 2 •s•Pa)) of PA6 at different test temperatures and pressures.…”

A Study on the Thermal Behavior of Series and Parallel Connection Methods in the Process of Hydrogenation of Ship-Borne Hydrogen Storage Cylinder

“…The efficiency and safety of their charging process have always attracted attention [14]. Li et al [15] conducted an experimental study on the aging of a thermoplastic gasket of a Type IV composite HST in order to ensure the safety performance of the HST. Zhao et al [16] carried out a cold compression method for hydrogen storage and performed theoretical and simulation research on the winding of multi-layer carbon fiber in HSTs.…”

Review of the Hydrogen Permeation Test of the Polymer Liner Material of Type IV On-Board Hydrogen Storage Cylinders

“…Currently, the most mature and widely used approach to on-board hydrogen storage is high-pressure gaseous hydrogen storage, primarily utilizing the on-board type III and type IV hydrogen storage cylinders with nominal working pressures (NWP) of 35-70 MPa [11,12]. Among HFCVs, the type IV hydrogen storage cylinder has become a research hotspot due to its advantages of being type IV hydrogen storage cylinder has become a research hotspot due to its advantages of being lightweight, having high hydrogen storage density, and good fatigue performance [13,14]. The structure of the type IV hydrogen storage cylinder and the polymer liner are shown in Figure 1.…”