US 12,435,433 B2
Methods and systems for monitoring electrochemical cell performance and cleaning metal ions from proton exchange membrane water electrolyzers
Tenzin Nanchung, Somerville, MA (US); and David Eaglesham, Lexington, MA (US)
Assigned to ELECTRIC HYDROGEN CO., Devens, MA (US)
Appl. No. 18/703,599
Filed by ELECTRIC HYDROGEN CO., Natick, MA (US)
PCT Filed Feb. 3, 2023, PCT No. PCT/US2023/012281
§ 371(c)(1), (2) Date Apr. 22, 2024,
PCT Pub. No. WO2023/150270, PCT Pub. Date Aug. 10, 2023.
Claims priority of provisional application 63/306,592, filed on Feb. 4, 2022.
Prior Publication US 2024/0337032 A1, Oct. 10, 2024
Int. Cl. C25B 15/00 (2006.01); B08B 3/08 (2006.01); C11D 7/26 (2006.01); C25B 9/77 (2021.01)
CPC C25B 15/00 (2013.01) [B08B 3/08 (2013.01); C11D 7/265 (2013.01); C25B 9/77 (2021.01)] 14 Claims
OG exemplary drawing
 
1. A method of monitoring an operational performance of membranes of a plurality of electrochemical cells within an electrochemical stack, the method comprising:
measuring, by a plurality of sensors, first operational voltages of the plurality of electrochemical cells at a first time;
measuring, by the plurality of sensors, second operational voltages of the plurality of electrochemical cells at a second time;
calculating, by a processor, an average change in an overall operational voltage of the plurality of electrochemical cells over a period of time defined by a difference between the first operational voltages and the second operational voltages divided by a difference between the first time and the second time, wherein the calculation of the average change is a weighted average in which at least one sensor of the plurality of sensors is provided a higher weight than another sensor of the plurality of sensors based on a measurement location of the at least one sensor within the electrochemical stack;
comparing, by the processor, the average change in the overall operational voltage to a threshold value;
adding a cleaning composition only to an inlet water stream that is supplied to an anodic inlet of the electrochemical stack for an electrolysis reaction to remove metal ions at the membranes of the plurality of electrochemical cells within the electrochemical stack when the average change in the overall operational voltage equals or exceeds the threshold value, wherein the adding is performed in situ during operation of the electrochemical stack comprising operating conditions for carrying out the electrolysis reaction, and wherein the cleaning composition comprises an acidic composition having a pH that does not leach other metals into the inlet water stream;
reacting the cleaning composition with the metal ions at the membranes of the plurality of electrochemical cells during the operation of the electrochemical stack to form an acidic-metal compound; and
transferring a product of the electrolysis reaction of the cleaning composition and the metal ions from the membranes and the plurality of electrochemical cells, therein removing at least a portion of the metal ions from the membranes of the plurality of electrochemical cells during the operation of the electrochemical stack.