Moisture and carbon dioxide management system in electrochemical cells
An electrochemical cell utilizes an air flow device that draws air through the cell from a scrubber that may be removed while the system is operating. The negative pressure generated by the air flow device allows ambient air to enter the cell housing when the scrubber is removed, thereby enabling continued operation without the scrubber. A moisture management system passes outflow air from the cell through a humidity exchange module that transfers moisture to the air inflow, thereby increasing the humidity of the air inflow. A recirculation feature comprising a valve allow a controller to recirculate at least a portion of the outflow air back into the inflow air. The system may comprise an inflow bypass conduit and valve that allows the humidified inflow air to pass into the cell inlet without passing through the scrubber. The scrubber may contain reversible or irreversible scrubber media.
1. An electrochemical cell comprising:
a cell housing defining an air chamber, an inflow port, and an outlet, the inflow port and the outlet in fluid communication with one another via the air chamber;
an electrolyte disposed in the air chamber;
a pair of electrodes spaced apart from one another in the electrolyte in the air chamber;
a humidity exchange membrane having an inflow side and an outflow side, the inflow side exposed to air entering the cell housing through the inflow port, the outflow side exposed to air exiting the cell through the outlet, and moisture movable through the humidity exchange membrane from the outflow side to the inflow side; and
a scrubber including scrubber media in fluid communication between the inflow side of the humidity exchange membrane and the inflow port of the cell housing, and carbon dioxide from air flowing through the scrubber removable by the scrubber media.
2. The electrochemical cell of claim 1 , wherein the humidity exchange membrane includes an ionically conductive polymer or perfluorosulfonic acid polymer.
3. The electrochemical cell of claim 1 , wherein the scrubber media is irreversible scrubber media.
4. The electrochemical cell of claim 3 , wherein the irreversible scrubber media includes soda lime, sodium hydroxide, potassium hydroxide, lithium hydroxide, lithium peroxide, calcium oxide, calcium carbonate, serpentinite, magnesium silicate magnesium hydroxide, olivine, molecular sieves, amines, monothanolamine, and/or combinations thereof.
5. The electrochemical cell of claim 1 , wherein the scrubber media comprises a reversible scrubber media.
6. The electrochemical cell of claim 5 , wherein the reversible scrubber media comprises amine groups.
7. The electrochemical cell of claim 1 , wherein the scrubber includes a heating element.
8. The electrochemical cell of claim 7 , wherein the heating element is a passive heating element that directs heat from the cell to the scrubber media.
9. The electrochemical cell of claim 7 , wherein the heating element comprises an electric heating element.
10. The electrochemical cell of claim 1 , wherein the scrubber is releasably attachable to the cell housing.
11. The electrochemical cell of claim 10 , wherein the electrochemical cell is operable with the scrubber detached from the cell housing.
12. The electrochemical cell of claim 1 , further comprising a recirculation feature through which a portion of air exiting the cell through the outlet is transferrable to inlet airflow movable over the inflow side of the humidity exchange membrane.
13. The electrochemical cell of claim 12 , wherein the portion of air transferrable to the inlet airflow, via the recirculation feature, is adjustable.
14. The electrochemical cell of claim 12 , wherein the recirculation feature is a valve.
15. The electrochemical cell of claim 12 , wherein the recirculation feature is a baffle.