Investigations on transfer of water and vanadium ions across Nafion membrane in an operating vanadium redox flow battery

Simulation of the self-discharge process in vanadium redox flow battery

“…(1)- (3)), C is differentiated twice in the diffusion term, which implies that the diffusion flux vector's y component must be multiplied by (1/scale) 2 . The convective term is only differentiated once, and therefore must be multiplied by a factor of 1/scale.…”

“…For VRFB, the loss of energy capacity is mainly caused by self-discharge, i.e. the crossover of vanadium ions across the cation exchange membrane [1][2][3][4][5].…”

“…The diffusion coefficient of vanadium ions across the cation exchange membranes (CMS, CMV, CMX and Nafion) has been determined by Wiedemann et al [1] and Sun et al [2]. The transfer behavior of water across the commercial ion exchange membrane has been studied with a static dialysis cell by Sukkar and Skyllas Kazacos [3] and Mohammadi et al [4], respectively.…”

“…The transfer behavior of water across the commercial ion exchange membrane has been studied with a static dialysis cell by Sukkar and Skyllas Kazacos [3] and Mohammadi et al [4], respectively. Moreover, Sun et al [2] has investigated the transfer behavior of water and vanadium ions in self-discharge process and charge-discharge cycles by employing a kilowatt-class stack. However, most researches are focusing on the experimental studies and the conclusions are appropriate only for a certain condition.…”

“…The model uses the basic mass transport theory and the parameters tested by Sun et al [2] to simulate the transfer of vanadium ions in the battery. Based on the calculation of diffusion flux of vanadium ions, the self-discharge processes in a kilowatt-class stack at the initial state of charge (SOC) of 0 and 65% are simulated.…”