Methods and systems for rebalancing electrolytes for a redox flow battery system

Patent metadata

Field	Value
Publication number	US-2018316033-A1
Application number	US-201815965728-A
Country	US
Kind code	A1
Filing date	Apr 27, 2018
Priority date	Apr 28, 2017
Publication date	Nov 1, 2018
Grant date	—

Abstract

A rebalancing reactor for a redox flow battery system may include a first side through which hydrogen gas is flowed, a second side through which electrolyte from the redox flow battery system is flowed, and a porous layer separating and fluidly coupled to the first side and the second side, wherein, the hydrogen gas and the electrolyte are fluidly contacted at a surface of the porous layer, and a pressure drop across the second side is less than a pressure drop across the porous layer. In this way, rebalancing of electrolyte charges in a redox flow battery system may be performed with increased efficiency and cost effectiveness as compared to conventional rebalancing reactors.

First claim

1 . A rebalancing reactor for a redox flow battery system, including:
a first side through which hydrogen gas is flowed, a second side through which electrolyte from the redox flow battery system is flowed, and a porous layer separating and fluidly coupled to the first side and the second side, wherein, the hydrogen gas and the electrolyte are fluidly contacted at a surface of the porous layer, and a pressure drop across the second side is less than a pressure drop across the porous layer.

2 . The rebalancing reactor of claim 1 , wherein the pressure drop across the second side corresponds to a pressure drop across an inlet and an outlet of the second side.

3 . The rebalancing reactor of claim 1 , wherein a pressure drop across the first side is greater than the pressure drop across the second side.

4 . The rebalancing reactor of claim 1 , further comprising an ejector, wherein the electrolyte exiting the second side flows through the ejector thereby drawing the hydrogen gas exiting the first side through the ejector.

5 . The rebalancing reactor of claim 1 , further comprising an ejector, wherein the electrolyte entering the second side flows through the ejector thereby drawing the hydrogen gas exiting the first side through the ejector.

6 . The rebalancing reactor of claim 1 , wherein the first side includes an interdigitated flow field through which the hydrogen gas is flowed, thereby forcing the hydrogen gas entering the first side through the porous layer prior to exiting the first side.

7 . The rebalancing reactor of claim 1 , wherein the second side includes an interdigitated flow field through which the electrolyte is flowed, thereby forcing the electrolyte entering the second side through the porous layer prior to exiting the first side.

8 . The rebalancing reactor of claim 1 , further comprising a negative electrode and a positive electrode conductively coupled to the porous layer, wherein electric current applied across the negative electrode and the positive electrode increases a rebalancing reaction rate between the hydrogen gas and the electrolyte.

9 . A method of operating a rebalancing reactor for a redox flow battery, including:
flowing hydrogen through a first side of the rebalancing reactor, flowing electrolyte from the redox flow battery through the second side of the rebalancing reactor without flowing the electrolyte through the first side of the reactor, and fluidly contacting the hydrogen gas and the electrolyte at a surface of a porous layer interposed between the first side and the second side.

10 . The method of claim 9 , wherein flowing hydrogen through the first side includes flowing hydrogen through the first side without flowing hydrogen through the second side.

11 . The method of claim 9 , wherein flowing electrolyte from the redox flow battery includes flowing electrolyte from a positive electrolyte chamber of the redox flow battery.

12 . The method of claim 9 , wherein flowing electrolyte from the redox flow battery includes flowing electrolyte from a negative electrolyte chamber of the redox flow battery.

13 . The method of claim 9 , wherein fluidly contacting the hydrogen gas and the electrolyte at the surface of the porous layer includes reducing metal ions in the electrolyte with the hydrogen gas at a carbonaceous surface of the porous layer.

14 . The method of claim 9 , further comprising maintaining a pressure drop across the second side less than the pressure drop across the porous layer.

15 . The method of claim 14 , wherein maintaining the pressure drop across the second side less than the pressure drop across the porous layer includes maintaining a pressure drop across the first side less than a bubble pressure of the porous layer.

16 . The method of claim 14 , wherein maintaining the pressure drop across the second side less than the pressure drop across the porous layer includes maintaining a pressure drop across the second side less than a bubble pressure of the porous layer.

17 . The method of claim 14 , wherein maintaining the pressure drop across the second side less than the pressure drop across the porous layer includes maintaining the pressure drop across the second side less than the pressure drop across the porous layer by more than a threshold pressure difference.

18 . A redox flow battery system including,
a plurality of redox flow battery cells, and first rebalancing reactor fluidly coupled to a second rebalancing reactor, each of the first and second rebalancing reactors including, a first side through which hydrogen gas is flowed, a second side through which electrolyte from the plurality of redox flow battery cells is flowed, and a porous layer separating and fluidly coupled to the first side and the second side, wherein, the hydrogen gas and the electrolyte are fluidly contacted at a surface of the porous layer, and a pressure drop across the second side is less than a pressure drop across the porous layer by less than threshold pressure difference.

19 . The redox flow battery system of claim 18 , further comprising a controller, with executable instructions stored in memory thereon to, responsive to the pressure drop across the second side of the first rebalancing reactor being less than the pressure drop across the porous layer by less than the threshold pressure difference, redirect a portion of the flow of the electrolyte from the first rebalancing reactor to the second rebalancing reactor.

20 . The redox flow battery system of claim 19 , wherein the executable instructions include, responsive to the pressure drop across the second side of the first rebalancing reactor being less than the pressure drop across the porous layer by less than the threshold pressure difference, reducing a flow of the electrolyte to the second side of the first rebalancing reactor.

Assignees

• Ess Technology Inc

Inventors

• Evans Craig E

Classifications

• H01M8/188

  by recharging of redox couples containing fluids; Redox flow type batteries · CPC title

• H01M8/04186

  of liquid-charged or electrolyte-charged reactants · CPC title

• H01M8/04276 Primary

  Arrangements for managing the electrolyte stream, e.g. heat exchange · CPC title

• H01M8/2455

  with liquid, solid or electrolyte-charged reactants · CPC title

• H01M8/0687 Primary

  Reactant purification by the use of membranes or filters · CPC title