Cold Start Behavior and Freeze Characteristics of a Polymer Electrolyte Membrane Fuel Cell

Vehicle applications require efficient cold start ability and durability of polymer electrolyte membrane fuel cells (PEMFCs). In this study, various self-cold start strategies including purging the PEMFC at shutdown and using galvanostatic operation at startup are proposed. The cold start characteristics from −5°C of a single cell are experimentally investigated in situ on a laboratory scale. The amount of cumulated charge transfer density, corresponding to the amount of product water, is used as an index to quantify the cold start capability. Gas purge at shutdown before freeze is found to facilitate the PEMFC cold start, although the improvement is relatively small compared with other methods such as gradually increasing the current during startup. Microscopic studies of the membrane electrode assembly (MEA) after cold start failure are conducted to determine material degradation due to ice formation.