Patent ID: 6068941
Filing Date: 2000-05-30
Classification: H01M,Y02E

Abstract:
A fuel cell system comprising:a stack of fuel cells, each fuel cell comprising a proton exchange membrane, a cathode catalyst and an anode catalyst disposed on opposing sides of said membrane, and coolant water flow fields adjacent to at least one of the anode and cathode sides of each of said membranes;an oxidant supply means for providing oxidant to the cathode;a coolant water circulating loop including a pump;characterized by the improvement comprising:a source of low molecular weight alcohol for providing to said coolant water circulating loop a sufficient quantity of alcohol to prevent water in said fuel cell system from freezing at a predetermined temperature, said source of alcohol being controllable to provide alcohol to said loop upon shut-down of said fuel cell; andsaid oxidant supply means operable to provide, upon start-up, a controlled flow of oxidant through said cathode reactant flow field, whereby alcohol diffusing from said water circulating loop to said cathode catalyst is oxidized, producing heat which warms said fuel cell.