Patent ID: 8148024
Filing Date: 2012-04-03
Classification: H01M,Y02E

Abstract:
1. A method of protecting a shut down proton exchange membrane fuel cell against freezing, said fuel cell system having a fuel cell with a proton-exchange membrane between a cathode and an anode, an external electrical circuit operatively connected to said cathode and said anode; a feed air supply in fluid communication with said cathode by a cathode line and operatively connected to said external electrical circuit; a hydrogen fuel source in fluid communication with said anode by an anode line; an electrical heater associated with said cathode line and operatively connected to said external electrical circuit; a sensor operatively positioned to measure a temperature of the fuel cell, wherein, when the temperature of said fuel cell measured by the sensor is below a predetermined value that is greater than 0 degrees Celsius, the method comprises the steps of: supplying hydrogen from said fuel source to said anode; connecting said anode and said cathode of said fuel cell to said external electrical circuit; dissociating the hydrogen at said anode into hydrogen ions and electrons; conducting an electrical current as a flow of the electrons along said external electrical circuit to said cathode; passing the hydrogen ions from said anode through said proton-exchange membrane to said cathode; combining the hydrogen ions with the electrons to generate hydrogen at said cathode; exothermal chemical reacting the hydrogen generated at said cathode with oxygen supplied by said feed air supply at rate of about the stoichiometric ratio for the chemical reaction; warming the feed air with said electrical heater, the electrical heater being powered at least in part by the electrical current conducted along the external electrical circuit; and distributing at least some of the heat generated in the exothermal chemical reacting step to the fuel cell.