First-ever lifetime test of a DMFC system lasting 25 600 h with a dynamic load profile of a material handling vehicle.

No abstract

IEK‐3 at Forschungszentrum Jülich successfully replaced the battery tray of a horizontal order picker (ECE 220, Jungheinrich) with a direct methanol fuel cell (DMFC) hybrid system in the kilowatt class. The DMFC combined with a lithium‐ion battery forms the hybrid drive for electrically driven horizontal order pickers. Such vehicles are used to transport and collect goods for orders in warehouses. The order picker is fueled by pure methanol to achieve a maximum range with the smallest possible space for the battery tray. An advantage of such energy systems is that there is no need for the relatively complicated and time‐consuming recharging of the conventional lead‐acid batteries, nor are spare batteries required for multishift operation. This study focuses on the influence of contamination with inorganic impurities on the durability of the 1 kW DMFC system V3.3‐1. The data from a long‐term test will be presented, in which the DMFC system was subjected to a realistic dynamic load profile for 3,000 h. The impurities identified in the post‐mortem analysis of the membrane electrode assembly will be outlined as well the influence of selected impurities, the sources of these impurities and how the DMFC V3.3‐2 system was modified on the basis of these findings.

Herein we discuss polymer electrolyte membrane (PEM) electrolysis stacks and systems we developed that are optimized for direct coupling to a photovoltaic (PV) panel. One advantage of PEM systems is their use of non-corrosive and non-toxic media. Thus, safe outdoor operation can be guaranteed, even in the case of a leakage. The system design was adapted to reduce the number of connection tubes, allowing for a series connection of multiple stacks at low cost and high reliability. One coupled PEM/PV system was tested under various temperature and irradiance conditions. All system components were also thoroughly characterized. The characterization was used to calibrate simple models of the individual components. Finally, the models were used to predict the system’s solar-to-hydrogen efficiency under different operating conditions and to find an optimal configuration for real-world outdoor operation.