Fuel cell technology adapted for cargo pedelecs

Kurzfassung

Today, 75% of the Europeans are living in cities. In these urban areas with a high density of population, transportation of goods and services is one of the most important reasons for traffic. Consequently, commercial transport causes 50% of the emissions and 30% of the urban vehicle miles. Many transportation duties in cities or industrial areas could be realized by cargo bicycles at lower costs, often faster and without doubts substantially more sustainable than with cars or other transport vehicles. Because of these advantages cargo bikes recently experienced great attention in urban delivery situations, triggered also by the growing transport demand from e-commerce. In combination with micro hubs electric cargo bikes can substitute combustion engine trucks and address the different socioeconomic issues mentioned above. For commercial application, two different approaches for the electrification of cargo bikes are promising: electro mobility by batteries (accumulators) or by fuel cells (polymer electrolyte membrane fuel cells) depending on the individual application. For duty applications fuel cell technology has many advantages towards batteries: Fast refuelling saves time, additional space for replacement accumulators is not required and waste heat can be used for cabin heating in winter. Furthermore, the environmental balance of production, life cycle and recycling, is better than in case of batteries. And finally fuel cell powered cargo bikes are the better alternative if high energy capacities are needed e.g. for operations over the whole day, on hilly grounds or with heavy loads. In the presented projects (FC-REX – Fuel Cell Range Extender, FCCP - Fuel Cell Cargo Pedelec), a modular system is developed based on a liquid cooled PEM fuel cell stack with metallic bipolar plates. This system has a nominal electrical power output of around 350W, a peak power of 650W respectively and a 350 (700) bar hydrogen tank. One drawback of battery or fuel cell powered systems is their behaviour at low temperatures (sub-zero °C). This concerns especially the cold-start ability of the system, as it reduces efficiency and life time. Therefore, in many electrical systems an additional heater is added for heating up the device in the start-up phase at low temperatures. Due to the required electricity for heating,the range of the vehicle is reduced . For eliminating this disadvantage, the developed fuel cell system is equipped with a metal hydride based pre-heater, that will not consume fuel or electrical energy, but adsorption heat to address cold start. Actually, the pre-heater needs less than 60s for increasing the stack temperature from -20°C to at least 10°C. The presentation will give an overview of the complete system, its different components as well as on the status of the validation project.