Patent ID: 7972745

Claim:
A coolant system for cooling a fuel cell ( 4 ) in a PEM fuel cell power plant, said coolant system comprising: a) a coolant flow field ( 12 ) having a plurality of coolant channels ( 52 ) therein, said coolant channels including at least one water and gas-permeable porous wall, and said coolant channels containing a liquid coolant which is pressurized to a first pressure; b) a coolant inlet ( 54 ) for passing said coolant into said coolant channels; c) a coolant outlet ( 56 ); d) a porous plug ( 28 ) which is at least partly hydrophobic, said plug being disposed in said coolant outlet and said plug being gas permeable and liquid-impermeable at said first pressure whereby gases in said coolant can penetrate said hydrophobic porous plug, and liquid coolant cannot penetrate said porous plug; and e) a gas venting line ( 30 ) communicating with said hydrophobic porous plug, said gas venting line having a pressure which is less than said first pressure so as to be operative to vent gases from said coolant flow field which gases penetrate and pass through said hydrophobic porous plug.