Elektrokemisk sensor för styrning av bränslecell
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesisAlternative title
Electrochemical Sensor for Power Control of a Fuel Cell (English)
Telecommunication stations for surveillance, wireless communication nodes, and other applications require a main energy source, energy storage unit and a back-up energy system. In the last years, fuel cells have become a good replacement for diesel generators in remote and off-grid applications. Fuel cells provide several advantages like high energy efficiency, no moving parts, silent, scaling is a function of their surface area instead of volume, and reliability. Among the disadvantages there are equipment cost, and difficulties in hydrogen storage. Simplifying the control system of the hydrogen feed control will lower the equipment costs and allow the use of this technology for remote applications where the system is mainly fed by renewable sources, like solar panels, and constant maintenance represents an issue.
For this purpose the present work investigates the use of a single air-breathing micro fuel cell, used as a sensor cell that can serve to control a fuel cell energy backup system. First the sensor cell was tested under different conditions of temperature, hydrogen humidity, flooding, and hydrogen inlet flow in order to determine optimum operation conditions. Then the sensor cell was connected to the hydrogen outlet of a single cell or stack, receiving the remaining hydrogen that was not consumed by the stack. Further tests were performed by modifying the hydrogen flow, resistance value, and stack current output. During the experiments the sensor cell voltage was monitored. The results show that the micro fuel cell delivers a cell voltage signal sensible to the hydrogen inlet flow, which means it can be used to control the operation of a fuel cell stack. The sensibility of the voltage signal can be modified by means of the resistance connected to its circuit. The stability in time of the voltage signal was achieved by setting the sensor cell to 45 °C or higher.
Place, publisher, year, edition, pages
2015. , 54 p.
Fuel cells, stand-alone, off-grid, control system, renewable sources, air-breathing, micro fuel cell, sensor cell, energy backup system, temperature, hydrogen humidity, flooding, hydrogen flow, cell voltage.
Chemical Process Engineering
IdentifiersURN: urn:nbn:se:kth:diva-173905OAI: oai:DiVA.org:kth-173905DiVA: diva2:855878