The development of sustainable energy systems, for example using green hydrogen, plays an important role in tackling the current energy supply bottlenecks and achieving the two-degree target set out in the 2015 Paris Climate Agreement. The electrolysis of water to produce green hydrogen is a key technology in this context. Water electrolysers split water into the elementary components oxygen and hydrogen using electrical energy. If only energy from renewable sources is used, climate-neutral, so-called green hydrogen is produced. Renewable sources include solar, wind and tidal power plants in particular.

Hydrogen lead project H2Giga

The H2Giga project HyPLANT100 at the Chair of Production Systems (LPS) at Ruhr-Universität Bochum is researching and developing the efficient assembly and installation of large-scale electrolyser systems. The central research question here is how a system up to the gigawatt power range can be automatically configured and assembled from a large number of individual electrolysers in an application- and cost-optimized manner.

The aim of the project is to analyze how (partial) automation of skid assembly at decentralized locations and efficient assembly at the installation site can be achieved in order to increase assembly efficiency. As part of the project, robot-based tube screwing for the more economical production of electrolysers for green hydrogen will be examined in more detail. Physically, scaling the size of electrolysis stacks alone is only possible to a limited extent, so the interconnection of smaller units, also known as numbering-up, is being considered.

Flexibility of the assembly process

Assessments of manufacturing-like processes in medium-sized industrial companies have shown different suitability for automation using robot-based automation. With the help of co-engineering, it is possible to design products that are suitable for assembly and automation, so that work preparation and structural design can be coordinated during the process with the aim of improving suitability for assembly. The robot tool automates the assembly of hydrogen-carrying pipes by automatically measuring the required positions, picking up the pipe and assembling the two pipe fittings. Based on the evaluation of fitting tests and cycle time determinations, it can be stated that up to now human work has resulted in faster assembly, but that this causes a significantly higher error rate in the pipe fittings, which leads to costly quality assurance and the resulting rework. The robot tool developed can evaluate the quality of the screw connection in a process-integrated manner, which integrates the follow-up inspection into the automated process. A characteristic curve of the applied torque and typical process errors were identified in tests on a six-axis force-torque sensor.

Qualification of the developed robot tool

The research results are to be used in the long term to investigate further processes in connection technology and adapt them as a production system in line with the "economy of scale". The use of robot-based assembly of tube fittings in the construction of electrolysers can therefore have a significant impact on productivity and overall costs. In addition, robot-based processes can be adapted to different system configurations. Transferability to applications in the aerospace industry is a direct given due to the large number of pipes, as is the use, for example, on brake lines in the automotive sector and others.

The H2Giga project HyPLANT100 is funded by the German Federal Ministry of Education and Research (BMBF) as part of the "Hydrogen Republic of Germany" ideas competition and supervised by Project Management Jülich (funding code: 03HY114B).