Systems and methods for electrode assembly for redox flow battery system

Abstract

Systems and methods are provided for assembling and operating an electrode assembly for a redox flow battery system. In one example, the electrode assembly may include an inflatable housing in which a negative electrode spacer and a positive electrode may be positioned, wherein the inflatable housing may inflate responsive to applied internal pressure during operation of the redox flow battery system. In some examples, the electrode assembly may be assembled via roll-to-roll processing and may be mechanically and fluidically coupled to electrode assemblies of like configuration. In this way, tolerance stacking may be decreased, processing may be simplified, and costs may be reduced relative to molding-based processes for electrode assembly manufacturing.

1 . A method, comprising:
 sequentially stacking layers to form each membrane electrode assembly of a stack of membrane electrode assemblies via roll-to-roll processing; and   operating the stack of membrane electrode assemblies as a redox flow battery while pumping positive and negative electrolytes into the stack of membrane electrode assemblies through respective fluid manifolds, the fluid manifolds fluidically coupling each membrane electrode assembly of the stack of membrane electrode assemblies to one another.   
     
     
         2 . The method of  claim 1 , wherein sequentially stacking the layers to form each membrane electrode assembly of the stack of membrane electrode assemblies via roll-to-roll processing includes, for each respective membrane electrode assembly of the stack of membrane electrode assemblies, includes:
 welding a first conductive sheet to a first thermoplastic sheet;   positioning a negative electrode spacer on the first conductive sheet;   welding a second thermoplastic sheet to the first thermoplastic sheet;   welding a membrane sheet to the second thermoplastic sheet;   positioning a positive electrode on the membrane sheet;   welding a third thermoplastic sheet to the second thermoplastic sheet; and   welding a second conductive sheet to the third thermoplastic sheet; and thereafter   cutting the first, second, and third thermoplastic sheets from a roll of each respective thermoplastic sheet to form the respective membrane electrode assembly.   
     
     
         3 . The method of  claim 1 , wherein an electrical contact resistance between adjacent membrane electrode assemblies of the stack of membrane electrode assemblies is lower while the stack of membrane electrode assemblies is being operated as the redox flow battery than while the stack of membrane electrode assemblies is not being operated as the redox flow battery,
 wherein the stack of membrane electrode assemblies is expanded to a first volume via a first fluid pressure while the stack of membrane electrode assemblies is being operated as the redox flow battery,   wherein the stack of membrane electrode assemblies is contracted to a second volume via a second fluid pressure while the stack of membrane electrode assemblies is not being operated as the redox flow battery,   wherein the first volume is greater than the second volume, and   wherein the first fluid pressure is greater than the second fluid pressure.   
     
     
         4 . The method of  claim 3 , further comprising:
 electrically coupling testing probes to at least one membrane electrode assembly of the stack of membrane electrode assemblies while the stack of membrane electrode assemblies is not being operated as the redox flow battery;   conducting voltage testing of the at least one membrane electrode assembly of the stack of membrane electrode assemblies via the testing probes; and   responsive to identifying one or more degraded membrane electrode assemblies of the stack of membrane electrode assemblies during the voltage testing, replacing the one or more degraded membrane electrode assemblies.   
     
     
         5 . The method of  claim 1 , wherein each respective membrane electrode assembly of the stack of membrane electrode assemblies includes channeled electrolyte distribution inserts fluidically coupling an interior of the respective membrane electrode assembly to the fluid manifolds, and
 wherein the positive and negative electrolytes are admitted into the interior of each membrane electrode assembly of the stack of membrane electrode assemblies from the fluid manifolds via channels of the channeled electrolyte distribution inserts.   
     
     
         6 . A method, comprising:
 sequentially stacking and adhering layers to form a membrane electrode assembly via roll-to-roll processing;   adding the membrane electrode assembly to a membrane electrode assembly stack; and   operating the membrane electrode assembly stack as a redox flow battery while pumping positive and negative electrolytes into the membrane electrode assembly stack through respective fluid manifolds, wherein pumping positive and negative electrolytes inflates the membrane electrode assembly stack.   
     
     
         7 . The method of  claim 6 , wherein adding the membrane electrode assembly includes fluidically coupling an interior of the membrane electrode assembly to the membrane electrode assembly stack via a channeled electrolyte distribution insert. 
     
     
         8 . The method of  claim 7 , wherein the respective fluid manifolds are formed by interlocked channeled electrolyte distribution inserts. 
     
     
         9 . The method of  claim 6 , further comprising after forming the membrane electrode assembly conducting a pneumatic pressure test, including diagnosing a presence of a leak in seals of the membrane electrode assembly. 
     
     
         10 . The method of  claim 6 , wherein sequentially stacking and adhering layers to form the membrane electrode assembly includes forming a membrane electrode assembly housing by adhering extruded thermoplastic sheets or frames, adhering conductive sheets to an exterior of the membrane electrode assembly housing, and adhering a membrane sheet to an interior surface of the membrane electrode assembly housing. 
     
     
         11 . The method of  claim 10 , wherein the membrane sheet bisects an internal volume of the membrane electrode assembly into positive and negative electrode compartments while permitting ionic conduction therebetween. 
     
     
         12 . The method of  claim 6 , wherein adhering includes thermally welding. 
     
     
         13 . The method of  claim 6 , wherein adhering does not include applying adhesive. 
     
     
         14 . The method of  claim 6 , wherein pumping positive and negative electrolytes includes pumping positive and negative electrolytes comprised of iron ions. 
     
     
         15 . A method, comprising:
 feeding a first raw material sheet and a second raw material sheet from a respective roll;   placing one or more electrode components between the first raw material sheet and the second raw material sheet; and   thermally welding the first raw material sheet to the second raw material sheet, wherein the first and second raw material sheets are included in a membrane electrode assembly of a membrane electrode assembly stack configured to expand when operating as a redox flow battery.   
     
     
         16 . The method of  claim 15 , wherein the one or more electrode components is a negative electrode spacer or a positive electrode. 
     
     
         17 . The method of  claim 15 , wherein the first raw material sheet and the second raw material sheet are composed of materials which maintain structural integrity when thermally welded. 
     
     
         18 . The method of  claim 15 , wherein thermally welding includes thermally welding at adherence regions configured for hermetic sealing or structural integrity of the membrane electrode assembly. 
     
     
         19 . The method of  claim 15 , wherein the first raw material sheet and the second raw material sheet are one of extruded thermoplastic sheets, conductive sheets, or membrane sheets. 
     
     
         20 . The method of  claim 15 , further comprising cutting the first raw material sheet and the second raw material sheet to form the membrane electrode assembly.