LaWiKo

Motivation

Many industrial locations in Germany are undergoing a complete structural transformation from coal extraction and utilization to future-oriented sites for renewable energies and environmentally friendly technologies. In this context, in addition to focusing on renewable energy sources, energy storage plays a decisive role in achieving EU sustainability goals such as climate protection, affordable and clean energy, and resource utilization.

This is where the application-oriented R&D project LaWiKo comes in, with the core objective of creating unique conditions for the production of lightweight containers made of fiber-reinforced plastics for the mobile storage of hydrogen or H₂-based energy carriers. The targeted development of a high-rate manufacturing technology utilizes thermoplastic pre-consolidated tape materials, which are processed in a continuous broadband winding process into rotationally symmetric container structures. A precisely controlled laser-based local heating enables autoclave-free consolidation of the structural materials.

In combination with the technology modules of joining technology and coating technology, unique manufacturing possibilities are created to economically produce test specimens and prototypes with property profiles previously unattainable. In doing so, the excellent scientific competencies in plastics processing of the Institute for Structural Lightweight Design at TU Chemnitz, particularly the broadband winding technology for producing closed thermoplastic composite components, are synergistically linked with the laser and process engineering expertise in laser in-situ joining of the Fraunhofer IWS in Dresden.

Objectives and Approach

In previous projects, large-area composites made of thermoplastic multidirectional laminate semi-finished products were successfully produced using the CONTIjoin technology developed by Fraunhofer IWS. Compared to conventional lay-up systems, which increasingly rely on the use of solid-state and diode lasers whose wavelengths are primarily determined by the coupling behavior into the reinforcing fibers, the high absorption of the CO₂ laser radiation used in CONTIjoin within the polymer matrix represents a decisive advantage in terms of thermal process control. The focus of the project is the production of cylindrical tank structures made of multidirectional fiber-reinforced prepregs with a high lightweight construction ratio, which are intended in the future for use as high-pressure hydrogen storage tanks.

From the Fraunhofer IWS side, two key research focus areas are addressed:

• Development/adaptation of a laser system for broadband winding technology
• Laser structuring and thermal spraying of a barrier layer on pressure vessels

Innovation and Perspectives

The collaboration of both project partners enables the exploitation of the following potentials:

• Material innovation: The combination of laser processing and innovative plastics contributes to the development of new materials with tailored properties.
• Interdisciplinary research: Collaboration among experts from different fields enables interdisciplinary research approaches and the examination of complex questions from diverse perspectives.
• Industrial application: The integration of expertise in laser technology and plastics processing also offers potential for developing industrial solutions with high standards in terms of both production efficiency and product quality.