Induction of In-plane Current at Start-and-Stop Operations on a PEFC

Abstract

In-plane induction currents in electrodes and bipolar plates by reactant fed into a PEFC were evaluated using a 20-segmented cell. When hydrogen was fed into an anode in the condition of anode (negative electrode) and cathode (positive electrode) exposed air, in-plane currents were detected in both electrodes in spite of the open-circuit condition. In-plane currents of anode and cathode in each segment had opposite directions from each other and nearly equal quantity. Simultaneously, carbon dioxide and oxygen were also detected in the cathode exhaust.

Modeling and Investigation of Carbon Loss on the Cathode Electrode during PEMFC Operation

“…Because Reiser et al reported a "reverse current mechanism," 2 carbon losses under partial hydrogen starvation 3 and start-up 4 conditions have been discussed collectively as carbondegradation phenomena in PEMFCs, and the potentially fatal consequences have been noted. [5][6][7][8][9][10][11][12] Makharia et al suggested that only 1 h under conditions of partial hydrogen starvation caused a loss of more than 5 wt % carbon. 13 Takeuchi and Fuller reported that under severe conditions, a large carbon loss ͑Ͼ1 wt %͒ was expected during the start-up of the fuel cell when air and hydrogen gases were exchanged in the fuel cell anode.…”