Method and System for Rebalancing Electrolytes in a Redox Flow Battery System
A method of rebalancing electrolytes in a redox flow battery system comprises directing hydrogen gas generated on the negative side of the redox flow battery system to a catalyst surface, and fluidly contacting the hydrogen gas with an electrolyte comprising a metal ion at the catalyst surface, wherein the metal ion is chemically reduced by the hydrogen gas at the catalyst surface, and a state of charge of the electrolyte and pH of the electrolyte remain substantially balanced.
1 . A rebalancing reactor, comprising:
a catalyst bed including a substrate layer and a catalyst layer coated on the substrate layer, wherein the substrate layer is spirally wound into a jellyroll structure, wherein hydrogen gas and electrolyte are fluidly contacted at a surface of the catalyst layer.
2 . The rebalancing reactor of claim 1 , wherein the catalyst bed further comprises a spacing layer positioned on the catalyst layer.
3 . The rebalancing reactor of claim 2 , wherein the spacing layer comprises a non-conductive mesh.
4 . The rebalancing reactor of claim 1 , wherein substrate layer is a conductive substrate layer.
5 . The rebalancing reactor of claim 1 , wherein the substrate layer a carbon substrate.
6 . The rebalancing reactor of claim 1 , wherein substrate layer coated with the catalyst layer is porous and permeable to hydrogen gas, hydrogen ions, and electrolyte.
7 . The rebalancing reactor of claim 1 , wherein the electrolyte is electrolyte of a redox flow battery and includes Fe 3+ .
8 . A rebalancing reactor, comprising:
a catalyst bed including a substrate layer and catalyst layer coated on the substrate layer supported in a catalyst housing,
wherein the catalyst housing includes bottom shroud to prevent fluid from exiting a bottom of the catalyst bed and directing fluid radially outward.
9 . The rebalancing reactor of claim 8 , wherein the substrate layer is spirally wound into a jellyroll structure.
10 . The rebalancing reactor of claim 8 , wherein the catalyst housing includes baffles configured to distribute inlet fluid.
11 . The rebalancing reactor of claim 8 , wherein the catalyst housing further includes an upper shroud configured to direct fluid downward in an annular space between the catalyst bed and side walls of the catalyst housing.
12 . The rebalancing reactor of claim 8 , wherein the catalyst layer includes one or more of Pt, Pd, Ru, and alloys thereof.
13 . The rebalancing reactor of claim 8 , wherein the rebalancing reactor further includes a fluid recirculation device to direct electrolyte and hydrogen gas to the catalyst bed.
14 . The rebalancing reactor of claim 8 , wherein the rebalancing reactor further includes a fluid recirculation device to direct hydrogen ions and reduced metal ions from the catalyst bed to an electrolyte source.
15 . A redox flow battery, comprising:
a rebalancing reactor including a catalyst bed fluidly coupled to a redox flow battery cell; and
a controller comprising computer-readable instructions stored on non-transitory memory thereof that when executed enable the controller to:
determine a hydrogen leak in an electrode of the redox flow battery based on an imbalance of electrolyte state of charge; and
flow hydrogen from an external source in response to the hydrogen leak.
16 . The redox flow battery of claim 15 , wherein the imbalance of electrolyte state of charge is detected by an imbalance of a total amount of ferrous ions in a negative electrolyte of the redox flow battery cell and a total amount of ferric ions in a positive electrolyte of the redox flow battery cell.
17 . The redox flow battery of claim 16 , wherein the total amount of ferrous ions and total amount of ferric ions are measured by oxidation reduction potential of the positive electrolyte and the negative electrolyte.
18 . The redox flow battery of claim 15 , wherein the imbalance of electrolyte state of charge is determined by average electrolyte state of charge over a time interval.
19 . The redox flow battery of claim 18 , wherein the average electrolyte state of charge is compared to amounts of species calculated from total coulombs transferred by the redox flow battery cell to determine the imbalance of electrolyte state of charge.
20 . The redox flow battery of claim 15 , wherein the catalyst bed includes a substrate layer and a catalyst layer coated on the substrate layer.