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Thickness Mapping Using Multispectral Imaging

National Renewable Energy Laboratory

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Figure 1. Acquisition of data using a hyperspectral camera<br />
Figure 1. Acquisition of data using a hyperspectral camera

Technology Marketing Summary

Fuel cells are in higher demand than ever before and research firm Research and Markets expects the global fuel cell market to grow at 15.4% CAGR over the next decade to reach $12.5 billion by 2025. In particular, proton exchange membrane fuel cells (PEMFCs) have seen a boom in growth, accounting for 65% of global shipments in 2015. At the core of PEMFCs is the membrane electrode assembly (MEA), which contains a thin proton-conducting film that facilitates electrochemical production of electricity.

In an effort to reduce manufacturing costs and scale up output, manufacturers of MEA components have widely adopted roll-to-roll manufacturing techniques. This increase in capacity is coupled with new quality control issues, however. In order for MEAs to function properly and reliably they must be manufactured within a strict thickness tolerance and without defects, e.g. pinholes, bubbles, divots, or scratches. Thus, maximizing the benefits of roll-to-roll manufacturing for PEMFC membranes will require a more robust quality control mechanism.


Researchers at the National Renewable Energy Laboratory (NREL) have discovered a non-contact method of mapping the thickness of transparent or semi-transparent film as it moves at a constant speed through a web-line system. This novel approach to quality control uses multispectral imaging to yield real-time high resolution thickness maps across 100% of a membrane, even when it is on a substrate or sandwiched between two protective layers. The concept was proven using perflourosulfonic acid (PFSA) membranes, with and without reinforcement, ranging in thickness from 5 to 50 µm. It can be used for any transparent or semi-transparent films, with potential applications for thin film solar cells and many other membrane applications. 

  • Non-contact, non-destructive
  • Continuous in-line monitoring
  • Real-time, high resolution thickness maps (100% inspection)
Applications and Industries
  • Polymer electrolyte fuel cells and electrolyzers
  • Power generation for automotive, portable power, and stationary power
  • Hydrogen production
  • Polymer film and membrane industries
Technology Status
Technology IDDevelopment StageAvailabilityPublishedLast Updated
NREL ROI 16-96PrototypeAvailable05/16/201705/16/2017

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To: Erin Beaumont<>