About the project
Fuel cells are a promising technology for alternative energy supply of mobile and stationary applications. They are able to generate current and heat by converting hydrogen and oxygen into water. No green-house gases are produced which makes fuel cells a nature friendly future technology. Because of their high system-complexity, small changes in materials, manufacturing processes or assembly can lead to significant changes in performance and lifetime. They consist of components which have to withdraw the unsteady corrosive environment but still offer high electric conductivity and catalytic activity. Moreover, the components need to exhibit long lifetime and low costs. Hence, the need for accurate quality control concepts is of high importance for securing reliable products and for economic production of high values.
Today, most characterization techniques are cost-intensive and time consuming. In R&D electrochemical, potentiostatic or galvanostatic measurements are done which usually give information about just a small area of the fuel cell component. Inspection of a single cell within a stack or the whole fuel cell stack is very time consuming. However, regarding fuel cell mass production there is not enough time for a 100 % in-line inspection of all bipolar plates.
Optical 2-D and 3-D measurement technologies have the potential to offer high speed measurements with high accuracy characterization. But the correlations between optical surface parameters (accuracy geometry, defects etc.) and the performance of the individual components respectively their impact on the performance of the whole fuel cell system is not understood / correlated sufficiently, so that they can be applied for quality inspection in fuel cell production.
Thus, this project aims to develop very fast combined 2-D and 3-D surface measurement systems that will be used to identify optical quality / defects to define failure criteria in order to prove and improve fuel cell performance and lifetime as well as to reduce manufacturing and QC costs. The project addresses the areas of R&D, input control (sorting out defective components), production process control and optimization (e.g. speed of hydroforming pressure), manufacturing and final inspection.
Therefore, new significantly faster inspection concepts have to be developed. State-of-the-art devices do not fulfill the requirements concerning measurement time and reproducibility. This is why innovative hybrid concepts of combining high speed 2D and high accuracy 3D surface measurements methods are the aim of this project. This way the complete area of interest can be observed while points of certain interest can be examined further, if necessary.
By the end of the project, a demonstrator tool will be available which will be capable of characterizing critical components of a fuel cell stack with high speed and high accuracy. Therefore, the optical features of fuel cell components have to be studied in context to their impact on electrical, electrochemical and mechanical performance and lifetime. Therefore, the optical parameters will be put in correlation to the electrochemical performance. This will be, for example, the surface roughness of metallic bipolar plates and its impact on electric contact resistances or the color spectra of the catalyst layer its corresponding electrochemical activity. Finally, quality parameters for optical measurement will be defined and used for the development of innovative fuel cell components, new services in quality management and failure analysis. This will enable fuel cell manufacturers to introduce reliable, high speed inspection devices into their production lines and to compare their fabrication results with their requirements that have been identified throughout the development process.