Gas vent for electochemical cell

Abstract

An electrochemical cell system is configured to utilize an ionically conductive medium flowing through a plurality of electrochemical cells. One or more gas vents are provided along a flow path for the ionically conductive medium, so as to permit gasses that evolve in the ionically conductive medium during charging or discharging to vent outside the cell system, while constraining the ionically conductive medium within the flow path of the electrochemical cell system.

What is claimed is: 
     
         1 . A method for assembling an electrochemical cell system comprising:
 providing a cell module having a chamber configured to receive a liquid ionically conductive medium therein;   installing a fuel electrode configured to store a metal fuel therein into a cell chamber of the cell module;   providing a plate for the cell module, the plate having an upper portion and a lower portion, and a window being provided in an upper portion thereof;   installing an oxidant electrode and a separate gas permeable and liquid impermeable membrane on the plate, the gas permeable and liquid impermeable membrane being provided in the window of the plate, wherein the oxidant electrode comprises active material and wherein each of the oxidant electrode and the gas permeable and liquid impermeable membrane have an inner surface; and   joining the plate and the cell module such that the ionically conductive medium is prevented from permeating therebetween, and the oxidant electrode is spaced from the fuel electrode,   wherein the fuel electrode and the oxidant electrode are configured to, during discharge, oxidize the metal fuel at the fuel electrode and reduce an oxidant at the oxidant electrode to generate a discharge potential difference therebetween for application to a load;   wherein the plate is positioned along a portion of the cell module and configured to close the portion of the cell module to contain the ionically conductive medium therein;   wherein the inner surface of the oxidant electrode and the inner surface of the gas permeable and liquid impermeable membrane are positioned to face the chamber; and   wherein the gas permeable and liquid impermeable membrane provides a vent for the cell module to permit gas in the cell module to permeate therethrough for venting of the gas from the electrochemical cell system.   
     
     
         2 . The method of  claim 1 , further comprising providing ionically conductive medium in the cell module. 
     
     
         3 . The method of  claim 1 , wherein the gas permeable and liquid impermeable membrane comprises a fluoropolymer material. 
     
     
         4 . The method of  claim 3 , wherein the fluoropolymer material comprises polytetrafluoroethylene. 
     
     
         5 . The method of  claim 1 , wherein the cell module contains a flow path for the liquid ionically conductive medium therein, the flow path being configured to facilitate a flow of the ionically conductive medium through the electrochemical cell system. 
     
     
         6 . The method of  claim 1 , further comprising providing a charging electrode in the cell module in the form of a separate charging electrode spaced from the fuel electrode and the oxidant electrode. 
     
     
         7 . The method of  claim 6 , wherein the fuel electrode and the charging electrode are configured to, during re-charge, reduce a reducible species of the metal fuel to electrodeposit the metal fuel on the fuel electrode and oxidize an oxidizable species of the oxidant by application of a re-charge potential difference therebetween from a power source. 
     
     
         8 . The method of  claim 7 , wherein the fuel electrode comprises a series of permeable electrode bodies arranged in spaced apart relation; and
 wherein the spaced apart relation of the permeable electrode bodies enables the re-charge potential difference to be applied between the charging electrode and at least one of the permeable electrode bodies, with the charging electrode functioning as the anode and the at least one permeable electrode body functioning as the cathode, such that the reducible fuel species are reduced and electrodeposited as the metal fuel in oxidizable form on the at least one permeable electrode body, whereby the electrodeposition causes growth of the metal fuel among the permeable electrode bodies such that the electrodeposited metal fuel establishes an electrical connection between the permeable electrode bodies.   
     
     
         9 . The method of  claim 7 , wherein the reducible species of the metal fuel comprises ions of zinc, iron, aluminum, magnesium, or lithium, and wherein the metal fuel is zinc, iron, aluminum, magnesium, or lithium. 
     
     
         10 . The method of  claim 1 , wherein the ionically conductive medium comprises an aqueous electrolyte solution. 
     
     
         11 . The method of  claim 10 , wherein the aqueous electrolyte solution comprises sulfuric acid, phosphoric acid, triflic acid, nitric acid, potassium hydroxide, sodium hydroxide, sodium chloride, potassium nitrate, or lithium chloride. 
     
     
         12 . An electrochemical cell system comprising:
 a cell module comprising a cell chamber;   a fuel electrode comprising a metal fuel provided in the cell chamber;   a plate for the cell module, the plate having an upper portion and a lower portion, and a window being provided in an upper portion thereof, the plate having an oxidant electrode and a separate gas permeable and liquid impermeable membrane positioned thereon, the gas permeable and liquid impermeable membrane being provided in the window of the plate, the oxidant electrode comprising active material, and wherein each of the oxidant electrode and the gas permeable and liquid impermeable membrane have an inner surface; and   a liquid ionically conductive medium provided in the cell module for conducting ions between the fuel and oxidant electrodes to support electrochemical reactions at the fuel and oxidant electrodes,   wherein the fuel electrode and the oxidant electrode are configured to, during discharge, oxidize the metal fuel at the fuel electrode and reduce an oxidant at the oxidant electrode to generate a discharge potential difference therebetween for application to a load,   wherein the plate is positioned along a portion of the cell module and configured to close the portion of the cell module to contain the ionically conductive medium therein;   wherein the plate and the cell module are joined such that the ionically conductive medium is prevented from permeating therebetween, and the oxidant electrode is spaced from the fuel electrode,   wherein the inner surface of the oxidant electrode and the inner surface of the gas permeable and liquid impermeable membrane are positioned to face the cell chamber; and   wherein the gas permeable and liquid impermeable membrane provides a vent for the cell module to permit gas in the cell module to permeate therethrough for venting of the gas from the electrochemical cell system.   
     
     
         13 . The electrochemical cell system of  claim 12 , wherein the gas permeable and liquid impermeable membrane comprises a fluoropolymer material. 
     
     
         14 . The electrochemical cell system of  claim 13 , wherein the fluoropolymer material comprises polytetrafluoroethylene. 
     
     
         15 . The electrochemical cell system of  claim 12 , wherein the liquid ionically conductive medium is configured to flow in a flow path through and among the one or more electrochemical cells. 
     
     
         16 . The electrochemical cell system of  claim 15 , wherein the gas permeable and liquid impermeable membrane is positioned downstream along the flow path from the fuel electrode and the oxidant electrode, and configured to vent by permeation gases generated during electrochemical reactions at the fuel and oxidant electrodes. 
     
     
         17 . The electrochemical cell system of  claim 12 , further comprising a charging electrode in the cell module in the form of a separate charging electrode spaced from the fuel electrode and the oxidant electrode. 
     
     
         18 . The electrochemical cell system of  claim 17 , wherein the fuel electrode and the charging electrode are configured to, during re-charge, reduce a reducible species of the metal fuel to electrodeposit the metal fuel on the fuel electrode and oxidize an oxidizable species of the oxidant by application of a re-charge potential difference therebetween from a power source. 
     
     
         19 . The electrochemical cell system of  claim 12 , wherein the fuel electrode comprises a series of permeable electrode bodies arranged in spaced apart relation;
 wherein the spaced apart relation of the permeable electrode bodies enables the re-charge potential difference to be applied between the charging electrode and at least one of the permeable electrode bodies, with the charging electrode functioning as the anode and the at least one permeable electrode body functioning as the cathode, such that the reducible fuel species are reduced and electrodeposited as the metal fuel in oxidizable form on the at least one permeable electrode body, whereby the electrodeposition causes growth of the metal fuel among the permeable electrode bodies such that the electrodeposited metal fuel establishes an electrical connection between the permeable electrode bodies.   
     
     
         20 . The electrochemical cell system of  claim 12 , wherein the reducible species of the metal fuel comprises ions of zinc, iron, aluminum, magnesium, or lithium, and wherein the metal fuel is zinc, iron, aluminum, magnesium, or lithium. 
     
     
         21 . The electrochemical cell system of  claim 12 , wherein the ionically conductive medium comprises an aqueous electrolyte solution. 
     
     
         22 . The electrochemical cell system of  claim 21 , wherein the aqueous electrolyte solution comprises sulfuric acid, phosphoric acid, triflic acid, nitric acid, potassium hydroxide, sodium hydroxide, sodium chloride, potassium nitrate, or lithium chloride.