Method and apparatus for commencing operation of a fuel cell electric power generation system below the freezing temperature of water

A method of ceasing and commencing operation of an electric power generation system comprising a fuel cell stack connectable to an external electrical circuit for supplying electric current to said external circuit, said stack comprising at least one fuel cell, said at least one fuel cell comprising a membrane electrode assembly comprising an anode, a cathode, and a water permeable ion exchange membrane interposed between said anode and said cathode, said system further comprising a fuel reactant stream and an oxidant reactant stream, each of said reactant streams being flowable to said fuel cell stack, the method comprising the sequential steps of:

• (a) interrupting the supply of electric current from said fuel cell stack to said external circuit;
• (b) reducing the temperature of at least a portion of said membrane electrode assembly to below the freezing temperature of water;
• (c) commencing the supply of electric current to said external circuit from said fuel cell stack, in which the temperature of said at least a portion of said membrane electrode assembly is below the freezing temperature of water, such that the temperature of said portion exceeds the freezing temperature of water.

A freeze tolerant fuel cell electric power generation system comprising:

• a fuel cell stack connectable to an external electrical circuit for supplying electric current to said external circuit, said stack comprising at least one fuel cell, said at least one fuel cell comprising a membrane electrode assembly comprising an anode, a cathode, and a water permeable ion exchange membrane interposed between said anode and said cathode, said stack further comprising at least one passage for flowing a coolant stream comprising water, said at least one coolant passage having compliant means associated therewith for accommodating said expansion of freezing water within said at least one coolant passage;
• and
• a fuel reactant stream and an oxidant reactant stream, each of said reactant streams being flowable to said fuel cell stack.

A freeze tolerant fuel cell electric power generation system comprising:

• a fuel cell stack connectable to an external electrical circuit for supplying electric current to said external circuit, said stack comprising at least one fuel cell, said at least one fuel cell comprising a membrane electrode assembly comprising an anode, a cathode, and a water permeable ion exchange membrane interposed between said anode and said cathode;
• at least one conduit for flowing a fluid stream to said fuel cell stack, said conduit formed from electrically conductive material,
• wherein said external circuit comprises said conduit.