Fuel Cell Electrochemical Characterization before and after Break-in; Implications for End of Line Manufacturing Diagnostics
Authors: Garvie Ian James , Cvijovic Lazar , Almeida Pazmiño Gonzalo Alfonso , Niroumand Amir , Kjeang Erik 
Published: December 2024

Hydrogen fuel cells, particularly proton exchange membrane fuel cells (PEMFCs), are one of the leading technologies in the transition to clean energy. However, their manufacturing can be costly and time consuming, with one of the primary bottlenecks being end of line (EOL) quality assurance and quality control (QA/QC). First, before a PEMFC can have reliable and consistent performance, it must undergo a lengthy break-in procedure which can take several hours [1]. Furthermore, a cell or stack can have defects present before break-in, meaning that time and resources were wasted on a cell that was already faulty. Secondly, PEMFC stacks cannot be tested using potential controlled methods, only current controlled methods, meaning that many conventional electrochemical techniques such as cyclic voltammetry (CV) and linear sweep voltammetry (LSV) cannot be applied. This research aims to remedy these issues by developing novel stack compatible diagnostic methods that can detect PEMFC failures at EOL before break-in.

While there has been significant research into developing PEMFC break-in methods, namely developing faster methods which yield higher performance cells, research has been scarce on the characterization of pre break-in cells [1]. As such, there is limited understanding of the properties of individual cell components before break-in as well as how their measured properties might correlate to those of a post broken in cell. We therefore aim to understand the characteristics of PEMFC components before break-in and what component changes can be seen after break-in. From this understanding, we hope to be able to both detect faulty cell components before break-in as well as predict certain performance parameters. QA/QC diagnostics will be validated by testing cells which have been fabricated with known defects. The effect of temperature and humidity on these diagnostics, before and after break-in, is investigated as well.

Due to the lack of potential control over individual cells in a stack, current based electrochemical methods must be developed and used for in situ diagnostics. Currently, two methods are being investigated as alternatives to the commonly used potential controlled methods of CV and LSV. The first diagnostic method examined is the hydrogen/nitrogen concentration cell leak test described in [2], [3], which is a stack compatible alternative to LSV which quantifies the hydrogen gas crossover rate from anode to cathode at open circuit potential. The second method is the galvanostatic current sweep described in [4], [5] as an alternative to CV for ECSA characterization. While both of these methods have been proven in practice, they have yet to be tested in larger stacks which have been freshly manufactured. Therefore, these methods will be performed on cells before and after break-in under different humidity and temperature regimes to assess their applicability to EOL diagnostics and defect detection.

Acknowledgements

This work was supported by the Natural Sciences and Engineering Research Council of Canada, Mitacs, Greenlight Innovation, Canada Foundation for Innovation, British Columbia Knowledge Development Fund, Pacific Economic Development Canada, and Canada Research Chairs.

References

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