Review LKH₂ 2021

We are living in the midst of what may be the greatest social shift since the beginning of the Industrial Revolution. If the earth warms to significantly more than 1.5 degrees Celsius, significant climatic changes will occur. Meanwhile, digitalization is driving up our energy needs. This demand is being met primarily by fossil fuels: coal, oil and gas, which currently account for more than 80 percent of global primary energy consumption. In Germany it is just under two thirds. These energy sources produce around 85 percent of all greenhouse gas emissions, which should be reduced as quickly as possible so that the global climate does not pass its irreversible tipping point. Behind this, however, there lies a historic opportunity: to tap new potential for value creation and sustainable jobs in a global market of the future based not on limitless, but sustainable growth.

The German Federal Climate Change Act (KSG), which was amended in June 2021, therefore sets the target: by 2045, Germany is to become “climate neutral,” i.e., to have reduced all avoidable emissions and removed unavoidable residual emissions from the atmosphere. By 2030, emissions are to be reduced by 65 percent compared to 1990, which is ambitious in view of the fact that as recently as 2021 they were higher than at any time in that period – since 1990. The country is faced with a dilemma. To solve it, we need to reconcile ecology and economy, the digital revolution with the sustainable revolution, says philosopher and author Richard David Precht. What he means: We need to develop innovative technologies that are sustainable, efficient and economical at the same time. This is precisely what the scientists at Fraunhofer ILT are working on. Their key to success: cooperation.

Hydrogen: energy carrier of the future

A key element for the long-term success of the energy transition is hydrogen technology because climate-friendly hydrogen makes it possible to significantly reduce CO₂ emissions wherever energy efficiency is low and directly using electricity from renewable energies is not feasible. While this could be achieved when private vehicles travel great distances, hydrogen can pay off more significantly where, for example, trucks, ships or aircraft have to carry heavy goods very long distances thereby consuming immense amounts of energy. Other possible applications include centralized and decentralized power generation, alternative fuel or gas production, and as a raw material for industrial processes such as steel or ammonia production. There, hydrogen produced with electricity from renewable energy sources – at times of overproduction – can replace coal. In turn, peak-load power plants powered by hydrogen could ensure that the energy supply is secure.

For this reason, the German government has launched a wide range of funding measures for German research institutions and industrial companies in fuel cell and hydrogen technology. For example, the Federal Ministry of Transport and Digital Infrastructure BMVI has been supporting the Fraunhofer-Gesellschaft’s National Fuel Cell Production Action Plan with 80 million euros since September 2021. The financing is provided via the future fund of the “Concerted Action Mobility” and, according to the ministry, is intended to “advance the transformation of the automotive industry – here in particular the supplier industry.” Professor Reimund Neugebauer, President of the Fraunhofer-Gesellschaft, who is also convinced: “Hydrogen is a decisive factor for the energy turnaround that society as a whole is striving for. Hydrogen technologies occupy a key position in the transformation of industry towards sustainable value creation,” he continues. The Fraunhofer Institute for Laser Technology ILT has a key role in the Fraunhofer-Gesellschaft’s National Fuel Cell Production Action Plan. To put it bluntly: this is the place-to-be when it comes to production and manufacturing technologies with laser-based processes in the field of hydrogen technology.

Promoting cooperation and exchange

In order to provide a platform for interdisciplinary exchange between research and industry in the field of hydrogen technology, Fraunhofer ILT hosted the LKH₂ – Laser Colloquium Hydrogen for the first time in 2020. It took place for the second time in the middle of September 2021. Once again, co-initiator Professor Arnold Gillner, head of Fraunhofer ILT’s Ablation and Joining competence area, provided the content with vision and expertise. Dr. Alexander Olowinsky, group leader of Micro Joining at Fraunhofer ILT, guided the 70 or so participants through the program.

Over the course of two days, 12 speakers from different disciplines and industries shed light on how current laser technology can be applied in the field of hydrogen technology. Dr. Karsten Lange, project manager for Battery and Hydrogen Technology at Fraunhofer ILT, spoke about how the functionality of components can be optimized with laser technology. Along with Dr. Olowinsky, Dr. André Häusler – team leader for the micro joining of metallic materials at ILT – was responsible for organizing the LKH₂ and also played on home turf. He addressed the advantages of high-speed laser beam micro welding in the production of bipolar plates, the heart of the hydrogen fuel cell. “Together with experts from industry and research, we want to find out what the current problems are,” said Dr. Häusler, summing up the motivation at the beginning of the colloquium. “This is the most effective way to develop the best technological solutions.”

Many from the Fraunhofer cosmos were present, including Prof. Eike Hübner from Fraunhofer HHI in Berlin, Professor Christian Doetsch and Dr. Michael Joemann from Fraunhofer UMSICHT, Clemens Müller from Fraunhofer IPT, Prof. Christoph Leyens and Dr. Teja Roch from Fraunhofer IWS in Dresden, and Dr. Chistian Vedder from Fraunhofer ILT. The colloquium’s partners from industry were also strongly represented; present were, among others, 4D CEO Christoph Franz, Dr. Isabel Thome from Trumpf, Thibault Bautze-Scherff from Blackbird Robotersysteme in Garching and Florian Hugger, Head of R&D at BBW Lasertechnik.

Key component: the fuel cell

The LKH₂ once again focused on the key component of hydrogen technology: the fuel cell. It converts the chemical energy present in the molecular bonding of water and oxygen into electrical energy, i.e. electricity, and thus makes it usable in the first place. Depending on the power requirements, a defined number of fuel cells are arranged in stacks. Between each two cells there is a bipolar plate – this is the heart of every fuel cell. This plate’s central task is to connect the anodes of the fuel cells with the cathode of the respective neighboring cell in a physically and electrically conductive manner. The bipolar plates also direct the flow of the reaction gases. For this purpose, flow profiles (flow fields) are embedded in their surface. Hydrogen flows over one side and air over the other. They also regulate the removal of water vapor and the release of thermal and electrical energy.

At present, bipolar plates still account for a large proportion of the weight of a fuel cell and cause correspondingly high production costs. The weight and installation space of fuel cell stacks should be reduced and their power density increased so that they can be produced cost-effectively and are suitable for series production in the future. Producing them in large quantities has enormous savings potential and this is exactly where the LKH₂ begins. “In order to reduce costs and meet increasing demand, we need to be able to produce certain components at significantly greater efficiency,” says Dr. Olowinsky. “The production of bipolar plates plays a crucial role in this.”

Improving efficiency and effectiveness

Depending on the design, a fuel cell stack contains around 200 bipolar plates. They are usually made of metal, but increasingly also of compound materials, which are plastic matrices filled with graphite and welded to a frame. Research is being carried out on both at Fraunhofer ILT. What both processes have in common is that the entire circumference of the bipolar plate must be joined in a hydrogen-tight manner. This can result in seam lengths of more than 200 meters per fuel cell. Laser technology is particularly well suited for this process due to its great flexibility and high degree of automation throughout the entire process chain. “There is hardly a bipolar plate left in the world that is not laser welded,” says Dr. Häusler.

The current task in all research on hydrogen is to make the laser processes used even more efficient and productive with a view toward the big goal: readiness for series production. In addition to technical excellence, this requires that users, component manufacturers, beam source and machine manufacturers as well as process monitoring cooperate closely together, says Dr. Olowinsky: “We are not waiting, but moving forward. We have identified the tasks that still need to be solved and want to work on them now. Not when it is too late.” However, this will not work on its own. “If we want to decisively advance hydrogen technology, we need cooperation and exchange between research institutions and industrial partners, ideally also across borders. This is exactly why we have brought the LKH₂ into being.”

In the future, the activities within the framework of the Laser Colloquium Hydrogen will be further expanded to include an expert forum for research and industry. The third edition has already been scheduled; it will take place in Aachen on September 13 and 14, 2022.