Separator and fuel cell using thereof

Abstract

A fuel cell is provided therein with a metal separator for aiming at preventing corrosion and at reducing a contact resistance. The separator is compose of conductive passage board formed therein with passages, and a metal planar panel, the passage boards and the metal planar panel being superposed with one another. The metal planar panel is formed therein with a plurality of manifolds for passing reactive gas or cooling medium through an adjacent cell while the passage boards are formed therein with a plurality of meandering through channels for distributing the reactive gas or the cooling medium from the manifolds. Further, a part of the meandering through channels is superposed with a part or all parts of the manifolds, and a covering layer for preventing the metal planar panel from being corroded, and for restraining a growth of a nonconductive film is formed over an entire part of the metal planar panel or over at least a part thereof which makes contact with the meandering through channels.

1 . A separator for a fuel cell, comprising a metal planar panel and conductive passage boards which are superposed with each other, intervening therebetween the metal planar panel, the metal planar panel being formed therein with a plurality of manifolds for passing reactive fluid or cooling medium through an adjacent cell while the passage board is formed therein with a plurality of meandering through channels for distributing the reactive gas or the cooling medium from the manifolds, wherein a part of the meandering through channels is arranged so as to be superposed with a part or all parts of the manifolds.  
     
     
         2 . A separator for a fuel cell as set forth in  claim 1 , wherein a covering layer for preventing the metal planar panel from being corroded, and for restraining a growth of a nonconductive film is formed over an entire part of the metal planar panel or over at least a part thereof which makes contact with the meandering through channels.  
     
     
         3 . A separator for a fuel cell, comprising a metal planar panel and conductive and porous passage boards which are superposed with each other, interposing therebetween the metal planar panel, the metal planar panel being formed therein with a plurality of manifolds for passing reactive fluid or cooling medium through an adjacent cell while the passage board is formed therein with a plurality of meandering through channels for distributing the reactive gas or the cooling medium from the manifolds, wherein a part of the meandering through channels is arranged so as to be superposed with a part or all parts of the manifolds.  
     
     
         4 . A separator as set forth in  claim 3 , wherein gaskets are arranged so as to surround the passage boards.  
     
     
         5 . A separator for a fuel cell as set forth in  claim 3 , wherein a covering layer for preventing the metal planar panel from being corroded, and for restraining a growth of a nonconductive film is formed over an entire part of the metal planar panel or over at least a part thereof which makes contact with the meandering through channels.  
     
     
         6 . A separator for a fuel cell, comprising a planar panel formed therein with a plurality of manifolds for passing reactive fluid or cooling medium through adjacent cell, and a pair of conductive passage boards superposed with one another, interposing therebetween the planar panel, the passage boards being formed therein with a plurality of meandering through channels for distributing the reactive fluid or the cooling medium from the manifolds, wherein the planar panel is formed therein with slits in a part in which the two passage boards are superposed with each other when the passage boards which make contact with the planar panel are projected.  
     
     
         7 . A separator for fuel cell as set forth in  claim 6 , wherein the planar panel is made of metal, and a covering layer for preventing the planar panel from being corroded, and for restraining a growth of a nonconductive film is formed over an entire part of the metal planar panel or over at least a part thereof which makes contact with the meandering through channels.  
     
     
         8 . A separator for a fuel cell as set forth in  claim 6 , wherein the conductive passage boards are made of a porous conductive material.  
     
     
         9 . A separator for a fuel cell as set forth in any one of claims  1 ,  3  and  6 , wherein the metal planar panel is formed thereon with an outermost layer made of a material selected from a group consisting of stainless steel, nickel, nickel base alloy, titanium, titanium base alloy, niobium, niobium base alloy, tantalum, tantalum base ally, tungsten, tungsten base alloy, zirconium, zirconium base alloy, aluminum and aluminum alloy.  
     
     
         10 . A separator for a fuel cell as set forth in any one of claims  2 ,  5  and  7 , wherein the covering layer is composed of a-binder selected from a group consisting of a fluorine group binder, phenol group binder, an epoxy group binder, a styrene group binder, a butadiene group binder, a polycarbonate group binder, a ponlyphenylene sulfide group binder, a mixture thereof and a copolymer thereof, and a conductive material containing therein not less than one kind of carbon.  
     
     
         11 . A separator for a fuel cell as set forth in any one of claims  2 ,  5  and  7 , wherein the covering layer is conductive and anticorrosive, and in integrally incorporated with the passage board.  
     
     
         12 . A fuel cell comprising a fuel cell stack of power generation units each composed of an integrated electrolyte membrane electrode structure, and a pair of separator each including, a metal planar panel, and conductive passage boards superposed with each other, interposing therebetewen the metal planar panel, the metal planar panel being formed therein with a plurality of manifolds for passing reactive fluid or cooling medium through an adjacent cell while the passage boards are formed therein with a plurality of meandering through channels for distributing the reactive fluid or the cooling medium from the manifolds, a part of the meandering through passage is superposed with a part or all parts of the manifolds, power collector panels arranged outside of the fuel cell stack and end plates arranged further outside thereof.  
     
     
         13 . A fuel cell as set forth in  claim 12 , wherein among the power generation units, the passage boards which are provided at every other power generation unit are for cooling water.  
     
     
         14 . A separator for a fuel cell as set forth in  claim 12 , wherein a covering layer for preventing the metal planar panel from being corroded, and for restraining a growth of a nonconductive film is formed over an entire part of the metal planar panel or over at least a part thereof which makes contact with the meandering through channels.