Simulation of electric field control effects on the ion transport in proton exchange membranes for application in fuel cells and electrolysers
Publication date
2022-02-08
Document type
Forschungsartikel
Organisational unit
ISSN
Project
StBZuEL
Series or journal
International Journal of Hydrogen Energy
Periodical volume
47
Periodical issue
12
First page
7961
Last page
7974
Peer-reviewed
✅
Part of the university bibliography
✅
DDC Class
620 Ingenieurwissenschaften
Keyword
Electrically controllable membrane electrode assembly
Electric field modifier
Proton exchange membrane fuel cells
Dynamic behaviour
Dynamic control
Double layer capacitance
Abstract
The dynamic controllability of the fuel cell could be improved by the addition of an electric field modifier (EFM), to selectively boost or attenuate the flux of protons through the membrane and, thereby, influence cell performance. This approach follows the commonly accepted idea of the potential gradient across the membrane being the main driving force behind the proton transport in the membrane. To evaluate the applicability of the idea, a simulation model for a membrane with an integrated EFM is developed to study the effects on the membrane behaviour. First, a modified Poisson-Boltzmann-Model (1D) is developed to characterise the capacitive behaviour of the double layer at the EFM. The approach considers steric restrictions in the membrane pores to estimate the double layer capacitance and the range of the effect at the EFM. Second, the characteristic behaviour of the capacitance is implemented in a secondary current distribution model (2D) as a variable capacitance. In transient simulations, boost of the cell current by up to 82% and attenuation up to a complete reversal of the direction compared to the stationary operation are achieved. Thus, it was possible to show the potential of EFMs to influence the characteristics of fuel cells and electrolysers during transient operation.
Version
Published version
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