Abstract
Fuel cells are strong candidates to become the power sources of the 21th century. Despite, being close to mass market entry for several years, fuel cells still are still only found in prototypes and very few commercial products. The reason for this is that fuel cells currently suffer from too high production prices and too short life times, in relation to market requirements. The focus of this thesis has been to develop experimental techniques, that can aid in the development of making fuel cells cheaper and more durable.
The overall purpose of the experiments conducted in this project, is to provide
fundamental knowledge of the transport and electrochemical processes of PEM fuel cells and to provide methods for obtaining high quality data for PEM fuel cell simulation model validation.
In this thesis three different areas of experimental characterization techniques
was investigated, they include: Stack flow distribution tools, AC impedance spectroscopy and in situ temperature measurement techniques. Some of the methods used are well established techniques, such as AC impedance spectroscopy, and some are novel techniques developed in this project, such as the in situ temperature measurement methods.
In the area of stack flow and pressure distribution, the techniques of CFD, PIV and differential pressure measurements have been adopted to study flow phenomenons in the cathode manifold, with special emphasis on the manifold inlet conguration. It has been shown that these tools are excellent means for obtaining very detailed data of the manifold flow. Moreover, the tools complement each other well, as high quality validation data can be obtained from PIV measurements to verify CFD models.
AC Impedance Spectroscopy was used to thoroughly characterize a HTPEM
single cell. The measurement method was furthermore transferred onto a Labview platform, which signiffcantly improves the exibility and lowers the cost of using this method. This technique is expected to bea very important future tool, used both for material characterization, celldiagnostic, system optimization and as a control input parameter in fuel cell systems.
Two novel methods for measuring the in situ temperature was developed in this project. The methods were used primarily to study degradation issues on HT-PEM fuel cells. The method does however hold the potential to be used as a sensor in fuel cell control systems and to be transferred into a current density measurement tool.
It is the hope that the contribution of this thesis can aid in bringing fuel cells faster to the market. Fuel cells are a key technology needed to cope with the climate changes of the future.
The overall purpose of the experiments conducted in this project, is to provide
fundamental knowledge of the transport and electrochemical processes of PEM fuel cells and to provide methods for obtaining high quality data for PEM fuel cell simulation model validation.
In this thesis three different areas of experimental characterization techniques
was investigated, they include: Stack flow distribution tools, AC impedance spectroscopy and in situ temperature measurement techniques. Some of the methods used are well established techniques, such as AC impedance spectroscopy, and some are novel techniques developed in this project, such as the in situ temperature measurement methods.
In the area of stack flow and pressure distribution, the techniques of CFD, PIV and differential pressure measurements have been adopted to study flow phenomenons in the cathode manifold, with special emphasis on the manifold inlet conguration. It has been shown that these tools are excellent means for obtaining very detailed data of the manifold flow. Moreover, the tools complement each other well, as high quality validation data can be obtained from PIV measurements to verify CFD models.
AC Impedance Spectroscopy was used to thoroughly characterize a HTPEM
single cell. The measurement method was furthermore transferred onto a Labview platform, which signiffcantly improves the exibility and lowers the cost of using this method. This technique is expected to bea very important future tool, used both for material characterization, celldiagnostic, system optimization and as a control input parameter in fuel cell systems.
Two novel methods for measuring the in situ temperature was developed in this project. The methods were used primarily to study degradation issues on HT-PEM fuel cells. The method does however hold the potential to be used as a sensor in fuel cell control systems and to be transferred into a current density measurement tool.
It is the hope that the contribution of this thesis can aid in bringing fuel cells faster to the market. Fuel cells are a key technology needed to cope with the climate changes of the future.
| Original language | English |
|---|---|
| Publisher | |
| Print ISBNs | 978-87-89179-90-2 |
| Publication status | Published - Jun 2010 |