Water Vapor Transport Measurement across PEMs

Abstract

Water vapor transport through the PEM is one of the key parameters that can help achieve high performance and low-cost fuel cell system. Ex-situ water vapor transport rate (WVTR) measurement is extremely difficult and expensive to measure. This transport depends on many parameters such as ionomer equivalent weight, ionomer type, thickness, reinforcement, and operating conditions. This work presents a simplified and an inexpensive set-up that consists of fuel cell test stand, cell hardware, and a humidity sensor to measure WVTR at PEMFCs operating conditions in order to characterize and compare water transport properties of PEMs. WVTR is found to increase with decrease in EW and decrease in thickness. WVTR shows dependence on flow rates at fixed water vapor activity and increases by almost 2 times at flow rate from 0.1 to 4 L/min. WVTR is strongly dependent on RH% and increases by 4-5 times at RH from 30 to 100%. Overall, a simple and inexpensive set-up is developed which is capable of producing water vapor transport behavior of widely different PEMs.