As in any engineering component, manufacturing a bipolar fuel cell plate for a polymer electrolyte membrane (PEM) hydrogen fuel cell power stack to within its stated design tolerances is critical in achieving the intended function. In a bipolar fuel cell plate, the dimensional features of interest include channel width, channel height, channel parallelism, side wall taper, straightness of the bottom or side walls, plate parallelism, etc. Such measurements can be performed on Coordinate Measuring Machines (CMMs) with micro-probes that can access the narrow and deep channels. While CMM measurements provide high accuracy (less than 1 m), they are often very slow (several hours to measure a single plate) and unsuitable for the manufacturing environment. In this context, we describe a system for rapid dimensional measurement of bipolar fuel cell plates using two laser spot triangulation probes that can achieve comparable accuracies with those of a touch probe CMM, while offering manufacturers the possibility for 100% part inspection. We discuss the design of the system, present our approach to calibrating system parameters, present validation data, compare bipolar fuel cell plate measurement results with those obtained on a Mitutoyo UMAP  fiber probe CMM, and finally describe uncertainty in channel height and width measurements.
Citation: Measurement Science and Technology
Pub Type: Journals
channel height, channel width, dimensional metrology, Fuel cell, laser triangulation