Polymer electrolyte fuel cell stack

Abstract

A polymer electrolyte fuel cell stack that includes a cell laminate having a plurality of unit cells, which are laid one upon another and each of which includes a polymer electrolyte membrane, a pair of electrodes arranged across the polymer electrolyte membrane and having respective catalytic reaction layers, a separator having means for feeding a supply of fuel gas containing hydrogen gas to one of the electrodes, another separator having means for feeding a supply of oxidant gas to the other of the electrodes, and a manifold for feeding the supply of fuel gas or the supply of oxidant gas to the respective electrode and disposed on a side face of each unit cell. In the polymer electrolyte fuel cell stack, a sealing portion is disposed at least in the vicinity of each electrode. The polymer electrolyte fuel cell stack has excellent durability and productivity. Gasket sealing portions, a sealing portion for cooling water, and sealing portions for water and gas in an internal humidifying unit are composed of a polymer compound that has polyisobutylene as the backbone structure. This arrangement ensures high reliability.

1 . A polymer electrolyte fuel cell stack comprising a plurality of unit cells, each unit cell comprising a polymer electrolyte membrane, a pair of electrodes arranged across said polymer electrolyte membrane and having respective catalytic reaction layers, a first separator having means for feeding a supply of fuel gas containing hydrogen gas to one of said electrodes, and a second separator having means for feeding a supply of oxidant gas to the other of said electrodes, and a manifold for feeding at least one of the supply of fuel gas and the supply of oxidant gas to the respective electrodes, the manifold being disposed on a side face of the stack of unit cells, and a sealing portion being disposed inside of the manifold.  
     
     
         2 . The polymer electrolyte fuel cell stack in accordance with  claim 1 , wherein at least one of the first and second separators has a cooling means which includes a sealing portion.  
     
     
         3 . The polymer electrolyte fuel cell stack in accordance with  claim 1 , further comprising a humidifying unit that enables heat exchange between a flow of cooling water discharged from the polymer electrolyte fuel cell stack and a flow of fuel gas fed to the polymer electrolyte fuel cell stack and that simultaneously carries out heating and humidifying, the humidifying unit having a sealing portion.  
     
     
         4 . The polymer electrolyte fuel stack in accordance with  claim 1 , wherein at least a portion of the sealing portion comprises plural layers.