The effect of non-uniform compression on the performance of polymer electrolyte fuel cells

• Published in: Journal of power sources 2022-02, Vol.521, p.230973, Article 230973
• Main Authors: Kulkarni, Nivedita, Cho, Jason I.S., Jervis, Rhodri, Roberts, Edward P.L., Francesco, Iacoviello, Kok, Matthew D.R., Shearing, Paul R., Brett, Dan J.L.
• Format: Article
• Language: English
• Subjects: Assembly pressure; Neutron radiography; PEMFC; Simulation; Water management; X-ray computed tomography
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2021.230973

The mechanical compression used in the construction of PEFCs improves effective current collection and gas sealing, however it results in structural deformation of the MEA, affecting reactant transport with adverse consequences for the electrochemical performance of the cell. The present study uses X-ray CT to characterise MEA under compression and determine effective properties of the porous domain. The comprehensive modelling approach couples a structural model of the MEA under compression to a multi-phase, non-isothermal electrochemical performance model. Liquid water saturation in the cathode domain that promotes mass transport losses is validated with neutron radiography. Here, the structural model considers the fuel cell stacking process at three compressions and highlights the non-uniform distribution of porosity and effective properties under non-uniform cell compression, affecting localised current distribution and water transport. An increase in compression showed a negligible effect on the performance in the activation region, the performance was marginally improved in the ohmic region and significantly affected in mass transport region, promoting cell flooding. The non-uniform compression effects are found to be important considerations for robust modelling studies as it increases the nonuniformity in localised current, temperature and flooding that would further alter the durability of the fuel cell. [Display omitted] •Coupled structural and electrochemical modelling study of PEFC compression.•X-ray CT study of the MEA to generate modelling parameters and validate structural model.•Neutron radiography to validate the electrochemical model models at variable compressions.•Effect of compression and channel/land arrangement on the cell performance.•Effect of compression on water management and thermal performance.