Test of Surface Roughness for Bipolar plates for Vanadium Redox Flow Batteries and Biological Fuel cells

In order to define the surface roughness, it is necessary to define the parameters. Common parameters are the arithmetic average called Ra and the average of maximum peak to valley height of profile called Rz. The arithmetic and averaged maximum peak height are looked for in order to describe the surface quality of graphite compound panels from different manufacturing and aftertreatment processes. The corresponding measurements are taken relatively locally so that either a wide range of measuring points or always the same points have to be checked in order to obtain comparable, meaningful results. The surface roughness has a significant impact to the contact resistivity of the graphite material to the connecting parts like electrodes [8].