Crosspolarized NearUV/Vis Detector for Inline Quality Control of PEM Materials

Modern fuel cells have been in development since the 1960s and stand on the cusp of commercialization, but are held back by high manufacturing costs and expensive catalysts. Membrane costs alone can account for as much as 45% of the total cost of a commercial fuel cell system. Furthermore, manufacturing defects in the membrane can cascade into complete stack failure, which is expensive and time consuming to resolve. These defects are often not discovered until costly catalyst has been irreversibly applied and the MEA is fully assembled, leading to additional wasted materials and a slow correction of the coating process. To achieve large scale commercialization, fuel cell manufacturing needs a high efficiency, real time quality control system that can provide 100% inspection of the membrane at coating speeds up to 60 ft/min. Statement of how this problem or situation is being addressed Mainstream’s approach uses nearUV/Vis light to infer membrane film thickness, composition, and defects with a single detector, light source, and pair of cross polarizers. Mainstream’s Cross Polarized NearUV/Vis (CPNUVV) system simultaneously measures membrane thickness and determines and quantifies membrane defects in real time at rolltoroll coating speeds. This information can be relayed to a printer to mark defective membranes, allowing exclusion from catalyst coating as well as rapid feedback to correct the membrane coating process. Our approach enables two measurements to be performed with a single low cost detector and light source with no moving parts. In Phase I, Mainstream proved technology feasibility, developing the detector to a TRL 5 and demonstrating it on a membrane web line at speeds up to 100 ft/min. In Phase II, Mainstream will further develop the detector to a TRL 7, increase the resolution and operation speed, and demonstrate it on high speed rolltoroll membrane web lines. Commercial Applications and Other Benefits the CPNUVV Detector will help drive down costs and increase reliability of fuel cell membranes which are often still too expensive to compete with conventional power technologies. The early detection of defective membranes allows their removal before further coating or assembly steps, reducing costs by minimizing wasteful use of expensive platinum catalyst, labor used to construct stack materials, and defective returns from the customer. The CPNUVV Detector is not limited to fuel cell membranes and other membrane processes can benefit from improved quality control devices. Key Words: Fuel Cell, Quality Control, Membrane Electrode Assembly, PEM, Optical, Real time