Hydrogen generation technologies, like fuel cells, offer a key to climate-neutral energy supply and mobility. According to a current forecast by the Fuel Cells and Hydrogen 2 Joint Undertaking (FCH 2 JU), more than one million fuel cell vehicles (cars, trucks, buses, trains) and over 173,000 fuel cell-based combined heat and power (CHP) plants for stationary energy supply to buildings are expected to be in operation in Germany alone by 2030. Across Europe, there are more than five million vehicles and more than one million CHP systems in the same period. In 2019, Europe manufactured only 1.2 percent of the fuel cells placed on the market worldwide. With new manufacturing processes and tools, this share could still grow significantly, despite competition from the U.S. and Asia.
In fuel cells, gaseous energy carriers - mostly hydrogen - are converted into electricity. Alongside the membrane electrode unit, the bipolar plate is the most important component of the fuel cell: Several hundred of these metallic bipolar plates are installed in a single fuel cell and layered in stacks. Up to 7.3 billion of the metallic plates are needed in Europe alone to produce the above-mentioned number of vehicles and CHP plants.
However, bipolar plates also account for a significant share of production costs: Up to 45 percent of the production costs of a fuel cell are currently incurred in the manufacture of bipolar plates. This is due on the one hand to the complex production of the plates themselves, and on the other hand to the fact that the service life of the forming tools used is still too short. Optimizing the production of bipolar plates is therefore essential for cost-effective large-scale production of fuel cells.
The aim of the "HYEFFMILL" research project is to achieve significantly higher performance and more economical milling molds for bipolar plate molds. Bipolar plate molds could then be produced up to 40 percent faster using wear-optimized multi-blade micro-milling tools.
To achieve this goal, Zecha Hartmetall-Werkzeugfabrikation GmbH is working with the Fraunhofer IPT to develop high-performance, low-wear micro-milling tools. For efficient evaluation of the tool prototypes in milling experiments, the Fraunhofer IPT is first developing a largely automated optical inspection of the tool condition.
A second focus is on empirical modeling of the milling process to predict wear depending on the selected process parameters. Based on statistical design of experiments and subsequent conduction of cutting tests, a compensated toolpath planning for optimized milling process control is aspired. In this way, the geometric accuracy of the bipolar plate molds is to be increased.
ZECHA Hartmetall-Werkzeugfabrikation GmbH
75203 Königsbach-Stein (Project coordination)
Fraunhofer Institute for Production Technology IPT
The "HYEFFMILL" project is funded by the German Federal Ministry for Economic Affairs and Climate Action (BMWK) as part of the Central Innovation Program for SMEs (ZIM) of the BMWK Innovation Network.
VDI/VDE Innovation + Technik GmbH