Compared to electric vehicles, fuel cell vehicles, which carry hydrogen stored in tanks, are lighter and have significantly greater ranges. This latter factor is also important for short-haul aircraft and rail transport, where the first fuel cell-powered trains already achieve ranges of up to 1,000 km. Currently, only 60% of the German rail network is electrified. The remaining 40%, or about 13,000 km, can only be used by diesel locomotives. On these lines, in rural areas served by many passenger trains, up to 500,000 fewer tons of CO2 could be emitted in the future. Hydrogen can also contribute effectively to reducing industrial CO2 emissions. In the future, energy-intensive industries will be able to cost-effectively produce hydrogen from stationary electrolyzers powered by surplus (or their own) green wind or solar energy, which can be temporarily stored and reused when needed in fuel cell units.
Within the fuel cell manufacturing process chain, Rehm offers drying systems. These systems are used to manufacture both PEM fuel cells—so-called low-temperature fuel cells—and high-temperature fuel cells based on ceramic (SOFC) or metallic (MSC) membrane materials. The fuel cells are placed on the bipolar plate, which seals the reaction, distributes the flow of gas and oxidants, and collects the generated electrical current. To achieve the required total power output, the plates are assembled into stacks.
The production of both the membrane unit and the bipolar plate involves coating processes with solvent-based materials that must be dried safely and reliably. Rehm offers customized solutions for these systems, which meet the requirements for flexible drying, to scale these new processes from the prototype or laboratory phase to an industrialized and automated production environment, thus making fuel cell production ready for series production.
Optimal Drying Process:
The Rehm drying system's optimal heat management, using upper and lower heaters, employs infrared (IR) radiation and/or convection to reliably dry a wide range of materials. By utilizing these two heat transfer processes, the systems are ideally suited for processing solvent-containing coating materials. Thermal insulation of the heating zones and individually adjustable temperatures allow for optimal tuning of the drying process, perfectly tailored to the requirements of fuel cell production.
Convection Drying:
In convection drying, the process atmosphere is heated by a hot air fan and then flows over the components. Heating elements are positioned above and below the conveyor system. The airflow rates in the upper and lower heating zones are individually adjustable to ensure uniform heating of the assembly. This prevents stress on the material.
Combined IR Heating Process
: In the combined heating process, heat is transferred by infrared radiation, which is supported by central convection heating. All heating chambers are equipped with high-performance IR radiators. The IR radiation penetrates the circuit board and expels the solvents from within. This enables a faster and more efficient drying process. For additional convection, the volume flow can be preset. The heating base of all IR radiators can also be fitted with glass covers to protect it from contamination and facilitate cleaning.
Integrated Exhaust and Extraction System:
The exhaust system ensures, among other things, the safe extraction of solvents. Suitable mechanisms are installed at the inlet and outlet of the process chamber, inserted between the heating zones. Exhaust air from the process is drawn directly into the building's extraction system via a fan. The extraction volume is determined by the substances to be hardened and the released exhaust products. The extraction function is controlled by a pressure sensor. In case of a problem, the heating is automatically switched off, and the intake of new components is stopped. This prevents the formation of flammable gas mixtures within the system.
