Method and apparatus for increasing the temperature of a fuel cell

Abstract

A method and apparatus increase the temperature of a fuel cell via reactant starvation at one or both electrodes. Reactant starvation at an electrode results in an increased overvoltage at the electrode and hence increased internal heat generation under load. Further, starvation techniques may be used to prevent poisoning of electrode catalysts, a potential problem that is aggravated at lower temperatures. Starvation conditions can be prolonged or intermittent and can be obtained, for example, by suitably reducing the supply rate of a reactant or by operating the fuel cell at sufficiently high current density so as to consume reactant faster than it is supplied. The method can allow for some generation of useful power by the fuel cell during start-up. The method is particularly suitable for starting up a solid polymer electrolyte fuel cell from temperatures below 0° C.

What is claimed is:  
     
         1 . A solid polymer electrolyte fuel cell apparatus comprising: an oxidant supply system for directing an oxidant reactant stream to a cathode electrode of said fuel cell; a fuel supply system for directing a fuel reactant stream to an anode electrode of said fuel cell; a temperature sensor for detecting the temperature of said fuel cell; and a control system for reactant starving at least one of said electrodes responsive to the output from said temperature sensor.  
     
     
         2 . The fuel cell apparatus of  claim 1  wherein said control system comprises apparatus for intermittently interrupting the supply of one of said reactant streams to said fuel cell electrodes.  
     
     
         3 . The fuel cell apparatus of  claim 1  wherein said control system comprises apparatus for connecting a transient electrical load to draw electrical power from said fuel cell.