Water recapture/recycle system in electrochemical cells

Abstract

A system for managing water content in one or more electrochemical cells, each comprising a plurality of electrodes and a liquid ionically conductive medium, includes a first gas-phase conduit for receiving humid gas-phase associated with the electrochemical cell. The system also includes a desiccator unit communicated to the first air conduit and configured for extracting water from the humid gas-phase. The system additionally includes a heater for selectively heating the desiccant to selectively release extracted water from the desiccator unit. The system further includes a return conduit communicating the desiccator unit to the ionically conductive medium for receiving extracted water from the desiccator unit, and directing the extracted water to the ionically conductive medium. Other associated systems and methods are also disclosed.

What is claimed is: 
     
         1 . A system for managing water content in one or more electrochemical cells, each electrochemical cell comprising a plurality of electrodes and an aqueous ionically conductive medium, the aqueous ionically conductive medium being contained at a level within a housing, the system comprising:
 a first gas-phase conduit for receiving humid gas-phase exiting from the one or more electrochemical cells;   a desiccator unit communicated to the first air conduit and configured for extracting water from the humid gas-phase;   a heater for selectively heating the desiccant to selectively release extracted water from the desiccator unit; and   a return conduit communicating the desiccator unit to the housing containing the aqueous ionically conductive medium of at least one of the electrochemical cells for receiving extracted water from the desiccator unit, and directing the extracted water to the aqueous ionically conductive medium of at least one of the electrochemical cells,   wherein each electrochemical cell comprises a fuel electrode, an air chamber, and an oxidant reduction electrode having one surface facing the aqueous ionically conductive medium and an opposite surface facing the air chamber,   wherein the fuel electrode is immersed in the aqueous ionically conductive medium, and   wherein said first air conduit receives the humid gas-phase as humid air from the air chamber of the one or more electrochemical cells.   
     
     
         2 . The system of  claim 1 , further comprising a fan for creating a flow of humid gas-phase into the first air conduit in communication with the desiccant unit. 
     
     
         3 . The system of  claim 1 , further comprising a fan for creating a flow of the humid air from the air chamber into the first air conduit. 
     
     
         4 . The system of  claim 3 , wherein the fan is coupled to an air inlet of the air chamber for receiving ambient air from outside the one or more electrochemical cells. 
     
     
         5 . The system of  claim 4 , further comprising a recirculation conduit for receiving an amount of the humid air from the air chamber and returning the received humid air back to the air chamber. 
     
     
         6 . The system of  claim 5 , further comprising an air inlet conduit coupled to the air inlet for receiving the ambient air from outside the cell, and wherein the air recirculation conduit is coupled to the air inlet conduit for mixing the amount of the humid air with the ambient air received from outside the one or more electrochemical cells as mixed air, such that the mixed air is delivered to the air chamber. 
     
     
         7 . The system of  claim 1 , further comprising a valve positioned between the air chamber and the desiccator unit, the valve configured to prevent extracted water from the desiccator unit returning to the air chamber. 
     
     
         8 . The system of  claim 1 , further comprising an air outlet for permitting an outflow of dry air from the desiccator unit after water has been extracted from the humid gas-phase, and a valve for selectively sealing the air outlet to prevent the outflow of dry air from the desiccator unit. 
     
     
         9 . The system of  claim 8 , wherein the valve associated with the air outlet comprises a three way valve movable between a first position coupling the desiccator unit with the air outlet, and a second position coupling the desiccator unit with the return conduit. 
     
     
         10 . The system of  claim 1 , further comprising a level sensor for determining the level of the aqueous ionically conductive medium. 
     
     
         11 . The system of  claim 10 , wherein the level sensor is coupled to the heater, and activates the heater to replenish water in the aqueous ionically conductive medium by heating the desiccator unit to release the extracted water from the desiccator unit. 
     
     
         12 . The system of  claim 1 , further comprising a thermocouple coupled to the return conduit and to the heater, the thermocouple determining when a flow of heated water in the return conduit ends, and deactivating the heater. 
     
     
         13 . The system of  claim 1 , wherein, during discharge of the one or more electrochemical cells, a valve between the desiccator unit and an air outlet is opened to permit an outflow of dry air from the desiccator unit after the water has been extracted from the humid gas-phase by the desiccator unit. 
     
     
         14 . The system of  claim 10 , wherein, during discharge of the one or more electrochemical cells, a valve between the air chamber and the desiccator unit is opened to permit humid air to flow along the first air conduit into the desiccator unit. 
     
     
         15 . The system of  claim 14 , further comprising a fan configured to create a flow of the humid air from the air chamber into the first air conduit during discharge, the fan being coupled to an air inlet configured to receive ambient air from outside the one or more electrochemical cells. 
     
     
         16 . The system of  claim 15 , wherein a portion of the humid air is diverted from the air chamber to the air inlet, to recirculate the portion of the humid air within the air chamber. 
     
     
         17 . The system of  claim 16 , wherein the valve between the air chamber and the desiccator unit, the valve between the desiccator unit and the air outlet, and the fan are selectively controlled to maintain a relative humidity in the air chamber of approximately 30-80%. 
     
     
         18 . The system of  claim 1 , wherein during charging of the one or more electrochemical cells, a valve between the desiccator unit and an air outlet is closed, and the heater is activated to heat the desiccator unit to release the extracted water from the desiccator unit. 
     
     
         19 . The system of  claim 18 , wherein during charging of the one or more electrochemical cells, a valve between the first air conduit and the desiccator unit is closed. 
     
     
         20 . The system of  claim 1 , wherein the extracted water is in the form of water vapor. 
     
     
         21 . The system of  claim 1 , wherein the desiccator unit comprises a desiccant. 
     
     
         22 . The system of  claim 21 , wherein the desiccant comprises one or more of silica gel, activated charcoal, aluminum oxide, calcium sulfate, calcium chloride, montmorillonite clay, and a molecular sieve. 
     
     
         23 . The system of  claim 1 , further comprising a manifold associated with the return conduit configured to couple the desiccator unit to a plurality of the one or more electrochemical cells. 
     
     
         24 . The system of  claim 23 , wherein a pressure head associated with the extracted water is configured to cause the extracted water to refill the aqueous ionically conductive medium of a first electrochemical cell of the one or more electrochemical cells having a lower level of the aqueous ionically conductive medium before refilling the aqueous ionically conductive medium of a second electrochemical cell of the one or more electrochemical cells having a higher level of the aqueous ionically conductive medium. 
     
     
         25 . The system of  claim 24 , wherein return inlets extending into the first electrochemical cell and the second electrochemical cell from the manifold define respective set levels for the aqueous ionically conductive medium for each of the first electrochemical cell and the second electrochemical cell; and
 wherein when the aqueous ionically conductive medium of the second electrochemical cell is at or above the respective set level for the second electrochemical cell, and the aqueous ionically conductive medium of the first electrochemical cell is below the respective set level for the first electrochemical cell, the pressure head is configured to cause back pressure at an intersection of the return inlet of the second electrochemical cell and the aqueous ionically conductive medium of the second electrochemical cell, to cause the extracted water to flow to the return inlet of the first electrochemical cell, and fill the aqueous ionically conductive medium of the first electrochemical cell to the respective set level of the first electrochemical cell.   
     
     
         26 . The system of  claim 25 , wherein the respective set level for the first electrochemical cell is the same as the respective set level for the second electrochemical cell. 
     
     
         27 . The system of  claim 1 , wherein the oxidant reduction electrode is mounted to a module immersed in the aqueous ionically conductive medium, the module defining the air chamber. 
     
     
         28 . The electrochemical cell system of  claim 1 , wherein the desiccator unit is coupled to the air chamber of each electrochemical cell. 
     
     
         29 . The electrochemical cell system of  claim 1 , wherein the return conduit communicates the extracted water to the aqueous ionically conductive medium of each electrochemical cell. 
     
     
         30 . A system for managing water content in a plurality of electrochemical cells, each electrochemical cell comprising a plurality of electrodes including a fuel electrode and an oxidant reduction electrode and an aqueous ionically conductive medium contained at a level within a housing, the system comprising:
 a desiccator unit for storing water;   a heater for selectively heating the desiccator unit to selectively release water vapor from the desiccator unit; and   a plurality of return conduits, each associated with a respective cell for communicating the desiccator unit to the aqueous ionically conductive medium of each cell for receiving the water vapor from the desiccator unit;   wherein each return conduit is configured to be blocked by a rising level of the aqueous ionically conductive medium within the housing, thus providing back pressure to the flow of the water vapor so that the water vapor preferentially flows to the unblocked return conduit or conduits, and   wherein each electrochemical cell further comprises an air chamber, wherein the oxidant reduction electrode has one surface facing the aqueous ionically conductive medium and an opposite surface facing the air chamber, and the fuel electrode is immersed in the aqueous ionically conductive medium.   
     
     
         31 . The system of  claim 30 , further comprising a manifold between the desiccator unit and the plurality of return conduits. 
     
     
         32 . The system of  claim 30 , wherein return inlets extending into each electrochemical cell from the respective return conduit define respective set levels for the aqueous ionically conductive medium for each of the plurality of electrochemical cells. 
     
     
         33 . The system of  claim 32 , wherein the respective set levels for each of the plurality of electrochemical cells are substantially the same.