Pilot Fabrication Facility
The development of automated production processes for cell and stack components is indispensable for the further development of fuel cells with a view to commercialization and improved quality.
IEK-3 has been pursuing this approach for many years with visible success both in the case of direct methanol fuel cells (DMFCs) and in promising initial activities for high-temperature polymer electrolyte fuel cells (HT-PEFC). In 2009, for example, IEK-3 put into operation a pilot fabrication facility equipped for the continuous automated production of cell components such as gas diffusion layers (GDLs), gas diffusion electrodes (GDEs), membrane electrode assemblies (MEAs), flow-fields and bipolar plates (BiPs), as well as for assembling cells and stacks. This facility will make an essential contribution with regard to cost reduction and reproducibility for the market launch of fuel cells in the near future.
Flexible Line Coater (Click & Coat)
Individual process modules can be integrated into the existing flexible line coater in order to carry out, study and optimize complex coating and treatment processes in a single cycle. For example, several different module functions can be selected for the process steps of coating, heat treatment as well as winding and cutting. Two sections of the facility can be operated at the same time using the two control terminals. With a web width of up to 0.5 m and a web speed between of 0.1 and 1 m/min, the facility can implement development tasks using small amounts of material and can fabricate components for prototypes. Since the facility has a wide temperature range, with a drying temperature of up to 235 °C and a sintering temperature of up to 400 °C, it is suitable for coating components both for DMFCs and HT-PEFCs.
Laboratory Coating Units
Laboratory facilities for slot coating and screen printing are available for direct coating onto one or both sides of a membrane in order to manufacture catalyst-coated membranes (CCM). A base coater is used to continuously coat membranes and transfer films by means of slot coating with either a horizontal or a vertical web guide and a working width of 20 cm. In addition, catalyst layers are deposited directly onto membranes using the existing screen printer, thus preventing contact problems.
For a commercial robot system, a universal quick-release system was developed that makes it very versatile and allows the different tools on the robot to be changed quickly and automatically.
The production facility can therefore alternate between gripper and adhesive applications to stack the components and simultaneously stick them together.
Fabrication of Stack Components
In order to fabricate sealant and flow distribution structures, the facility has a four-column laboratory press with a maximum extrusion force of 2,000 kN connected to the robot system for automatic loading and unloading. The line production of complex geometries with very long sheared edges is therefore feasible in terms of the stamping technology. Also a hot pressing module with a maximum extrusion force of 500 kN and temperatures up to 250 °C can be used for joining the GDEs with the membrane to the MEA.
Metallic materials for use in cell and stack components need to be coated with electrically conducting and at the same time corrosion-resistant materials. A laser coating system can be used to deposit such layers on bi-polar and contact plates while at the same time saving material and therefore money. With laser technology, the surface morphology can also be conditioned selectively, thus adapting the component mechanics to requirements in the stack