“Tomorrow's energy is water that has been decomposed by electric current. The elements of water thus decomposed, hydrogen and oxygen, will secure the earth’s energy supply for an unforeseeable period of time.” This is how Jules Verne raved about the fuel cell, the working principle of which the Swabian chemistry professor Christian Friedrich Schönbein discovered in 1838 during an experiment by serendipity. But the time was not yet ripe for Schönbein's gas battery, as he called it.
Is the breakthrough coming with the heavy-duty truck?
Jules Verne's vision may now become reality – but in road transport: More than 180 years later, Transport Minister Dr. Volker Wissing is counting on the major breakthrough of the fuel cell in mobile use, with 80 million euros in funding for truck fuel-cell production, which a consortium of 19 Fraunhofer institutes is to put into practice in the project “H2GO - National Fuel Cell Production Action Plan.” Coordinated by the Chemnitz-based Fraunhofer Institute for Machine Tools and Forming Technology IWU, the ambitious project is expected to help reduce the cost of hydrogen vehicles in heavy-duty transport significantly, according to Wissing.
The third LKH2 demonstrated how intensively research and industry are already working on this in Aachen. The colloquium focused on the series production of electrolyzers and fuel cells. Each of these so-called stacks requires around 300 to 400 bipolar plates (BPP) in addition to the membrane electrode unit. Production is still not only too slow, but also too expensive: Currently, the production of the so-called stacks costs a total of around 300 to 400 euros per kilowatt. The H2GO project is intended to help reduce costs to around 30 euros per kilowatt.
The basic research carried out by the experts at Fraunhofer ILT in their new 300 square-meter hydrogen laboratory can contribute to improving production. Although there are similar facilities throughout Germany, Fraunhofer’s lab has a special unique selling point according to Dr. Alexander Olowinsky, initiator of the LKH2 and head of the Joining and Cutting department at Fraunhofer ILT: “Since we offer a wide variety of practical applications, our new hydrogen lab is unique.” Guests at the LKH2, who experienced live demonstrations at the experimental facilities in September, were able to see for themselves how, for example, ultra-thin metal plates 70 to 100 micrometers thick can be precisely cut and reliably welded into gas-tight stacks with the laser.
The intensive demonstrations also focused on how typical problems can be prevented not only in the laboratory but also under series production conditions. Here, artificial intelligence (AI) has already proven itself many times over in Aachen. Fraunhofer ILT scientists presented two examples among many: the first by Dr. Frank Schneider, of the Macro Joining and Cutting group at Fraunhofer ILT, who presented the digital process online optimizer for intelligent laser machines (DIPOOL). Here, the Aachen researchers combine the temporal and spatial programmability and controllability of laser tools with machine learning for the first time. As part of the BMBF project DIPOOL, the institute is working closely with a completely new type of multispectral sensor technology from 4D Photonics GmbH in Isernhagen, which Managing Director Christoph Franz also uses as a “WeldWatcher®” for welding bipolar plates.
Take two: Siamese neural network compares sections
The second example was provided by Christian Knaak of the Process Sensors and Systems Technology Group at Fraunhofer ILT. Knaak relies on a so-called Siamese neural sensor network for the rapid detection of splashes in BPP laser micro welding, which does not analyze the entire image but only compares characteristic sections. Looking ahead to further research, Knaak suggested that not only should the actual laser process be monitored with AI assistance, but also upstream and downstream process steps should be targeted.
Metallic 3D printing is also suitable for use in plate production. Electrolysers for hydrogen production, for example, require components that often consist of special material pairings. Dr. Andreas Weisheit, head of the Coating LMD and Heat Treatment group at Fraunhofer ILT, described how the institute produces such plates using laser material deposition (LMD). During laboratory tours at the institute, the LKH2 guests saw how an LMD system coated a structural steel plate with a thin porous nickel-aluminum alloy.