Methods and apparatuses for managing fluids in a fuel cell system

A method for controlling flow in a fuel cell, comprising connecting said fuel cell to an electrical load, producing electrical energy, generating heat in response to the production of electricity by said fuel cell, automatically actuating a heat-sensitive valve for controlling said flow in response to said heat.

A fuel cell comprising a housing including an anode chamber having a fuel mixture, said anode chamber in communication with a fuel source, a cathode chamber in fluid communication with an oxidizing agent, a proton conducting membrane electrolyte separating said chambers, and a fuel concentration-actuated valve for automatically controlling a flow of fuel from said fuel source to said anode chamber.

A sensor for determining a concentration of fuel in a fuel mixture for a fuel cell comprising a conductor having a plurality of individual portions positioned proximate one another within a first material, wherein said first material automatically expands dependent upon exposure to a liquid medium.

A method for determining a concentration of fuel in a fuel cell comprising:

• providing a first material capable of expanding in response to a concentration of fuel in a fuel cell, wherein within said first material a conductor is positioned having a plurality of individual portions, and wherein upon a change in a concentration of fuel, contact between said plurality of individual portions correspondingly changes;
• flowing an electrical current through said conductor;
• measuring a resistance of said conductor, wherein as fuel concentration changes, the resistance of said conductor correspondingly changes..

A switch for a fuel cell, said fuel cell comprising a housing including an anode chamber in communication with a fuel source, a cathode chamber in fluid communication with an oxidizing agent, a proton conducting membrane electrolyte separating said chambers, said switch comprising a heat-actuated shape memory alloy wherein below a predetermined temperature, said switch is in a first position, and upon said fuel cell reaching said predetermined temperature said switch is switched to a second position.

A switch for a fuel cell, said fuel cell comprising a housing including an anode chamber in communication with a fuel source, a cathode chamber in fluid communication with an oxidizing agent, a proton conducting membrane electrolyte separating said chambers, said switch comprising a first material having expansion properties upon exposure to water, wherein said switch is in a first position prior to exposure to water and said switch is in a second position after said first material is exposed to water.

The switch according to claim 39, wherein a positioning of said switch between said first position and said second position is variable in a non-linear aspect in relation to an amount of water said first material is exposed to.

The switch according to claim 39, wherein said switch is placed in a third position upon exposure of said first material to a concentration of methanol.