Novel modular lightweight hydrogen tank design for maximum use of installation space

Today, modern lightweight tanks for hydrogen storage are already manufactured in fiber composite design (Type 4 tanks). In this case, a plastic liner provides extensive H₂ permeation resistance and the fiber reinforcement (usually carbon fiber, applied in a winding process) carries the mechanical loads. However, production by the winding process results in significant limitations with regard to geometry. On the one hand, such a cylindrical Type 4 vessel cannot be made arbitrarily small in diameter, since the fibers must be guided over a turning zone at the dome area of the pressure vessel in order to integrate metallic load introduction elements (dome) into the design and to ensure sufficient load-bearing capacity in the axial direction. On the other hand, such wound Type 4 vessels must be manufactured closed by the overwound dome area; subsequent accessibility to the interior (e.g. for maintenance or system integration) is very limited. Likewise, it is not possible to place fibers on the vessel purely in the axial direction in the winding process; it is imperative to maintain a winding angle in order to be able to realize the turning zone in the dome area. If it was possible to produce very slim and long lightweight pressure vessels in an economical process, these pressure vessels could e.g. be installed in the same space where the battery is in electric vehicles. Another disadvantage of common Type 4 pressure vessels is the need to manufacture a liner that already has the geometry of the pressure vessel before the winding process. Subsequent dimensional changes (length, diameter) to the design always necessitate the manufacture of a new liner geometry.

In the joint project Hydrogen combustion (WaVe) funded by BMWK, a tank system for a hydrogen-powered UNIMOG is being developed. The project partners Leibniz-Institut für Verbundwerkstoffe (IVW) GmbH, Daimler Truck AG, Commercial Vehicle Cluster – Nutzfahrzeug GmbH, comlet Verteilte Systeme GmbH, HYDAC Process Technology GmbH, Photonik-Zentrum Kaiserslautern e. V., Institut für Oberflächen- und Schichtanalytik (IFOS) GmbH and Thomas Magnete GmbH work closely together. In the project, IVW is developing a novel pressure vessel design for storing gaseous hydrogen (70 MPa) that overcomes the disadvantages of conventional type 4 tanks. The load is transferred from the axial layers in the cylindrical area of the pressure vessel, layer by layer with the help of the "IVW load introduction" patented by IVW. In this way, the metallic dome areas, which can be either closed or open, are integrated to carry the load. A metal or plastic tube, flexible in length and diameter, acts as a liner which can be easily replaced if the vessel geometry changes. Extensive numerical simulations have shown that the new design, with its purely axial and circumferentially applied fibers, has maximum lightweight properties and can also be manufactured very thinly. The first demonstrators have been manufactured and structural tests have demonstrated their suitability as pressure vessels. Within the WaVe project, it is planned to use the novel design as a tank module. For this purpose, seven pressure vessels will be combined into one tank module (conformable tank) which can be refueled via one OTV (on tank valve). This design allows maximum use of installation space and ensures the availability of a sufficiently large quantity of hydrogen so that mobile machines like the UNIMOG can be operated in one shift without restrictions.

The project „WaVe“ is funded by the Federal Ministry for Economics and Climate Action on the basis of a decision by the German Bundestag (funding reference 19I21028K).

Modulpartner/Partners:

Daimler Truck AG
Commercial Vehicle Cluster – Nutzfahrzeug GmbH
comlet Verteilte Systeme GmbH
HYDAC Process Technology GmbH
Photonik-Zentrum Kaiserslautern e. V.
Thomas Magnete GmbH

Contact:
Dr.-Ing. Nicole Motsch-Eichmann
Kompetenzfeldleiterin Bauweisen
Phone 0631 2017 423
E-Mail: nicole.motsch@ivw.uni-kl.de