Fraunhofer Institute for Mechanics of Materials IWMThe Zwanzig20-HYPOS joint project H2-HD worked on high-performance tank systems with high H2 storage density. The research focused on the cladding of a plastic hybrid tank.
H2-HD: Plastic Hybrid High-Pressure Tank Systems for High Hydrogen Storage Density
Completed research project
Project description
Green hydrogen can be stored in large storage facilities and transported in pipelines. In order for it to reach end customers in rural areas and gas stations in city centers where it can be temporarily stored, additional storage and transport tanks are required. Because gaseous hydrogen has a low volume-specific energy density, high-pressure tanks offer a practical storage solution. Pressure vessels with 350 bar, and in some cases 700 bar, are common on the hydrogen transport market. The project partners wanted to significantly increase this value. The goal was to develop particularly safe and lightweight containers that can be used at an operating pressure of up to 1000 bar. This will enable more efficient distribution and use of hydrogen.
Fraunhofer IWM subproject: Probabilistic evaluation of the operational behavior of wound CFRP high-pressure tanks, taking discontinuities into account (TP5)
So-called Type 4 tanks are particularly suitable for achieving this goal. These containers are encased in a carbon fiber reinforced plastic (CFRP) load-bearing structure. Inside is a thermoplastic liner that ensures gas tightness. In addition, there are metal elements at the ends of the container. The high loads and safety requirements placed on the CFRP tank shell pose a number of challenges – particularly with regard to operational aging and specific requirements in contact with highly compressed hydrogen.
In order to increase the efficiency of the high-pressure tanks, the mechanical behavior of the composite laminate was investigated at the micro, meso, and macroscopic levels. The following research questions were investigated, among others: How does the fiber-reinforced plastic laminate behave when the tank is filled or emptied? Does the bond between the liner and the shell remain stable? How does hydrogen interact with the various materials and what effects does this have on their aging and service life? How can the presence of manufacturing-related imperfections and defects (such as fiber angle deviations, pores, dry fibers) be controlled in numerical simulations, and how can their effects on the operation of the container be predicted using modern probabilistic assessment concepts?
Transfer of project results to R&D services provided by Fraunhofer IWM
- Based on an understanding of the materials used down to their microstructure, a novel macroscopic damage material model was developed that can be used for reliable prediction of component behavior.
- A probabilistic modeling concept was developed that allows the direct prediction of the influence of unavoidable manufacturing-related imperfections on the failure probability of the component.
- Extensive characterization was carried out, ranging from the material level on miniature samples to instrumented burst tests on model containers in cooperation with one of the project partners.
Funding information
