Method and System for Improving the Energy Efficiency and for Reconditioning of a Vanadium Flow Battery

Patent metadata

Field	Value
Publication number	US-2018331382-A1
Application number	US-201615756704-A
Country	US
Kind code	A1
Filing date	Sep 2, 2016
Priority date	Sep 2, 2015
Publication date	Nov 15, 2018
Grant date	—

Abstract

The present invention comprises a method and system for improving the energy efficiency of a vanadium flow battery, VFB. This is achieved by simultaneously reconditioning the VFB through in-situ activation of the electrodes.

First claim

1 . A method for improving the energy efficiency of a vanadium flow battery, VFB, comprising:
simultaneously reconditioning the negative electrode and the positive electrode of the VFB.

2 . The method of claim 1 , wherein the step of simultaneously reconditioning the negative electrode and the positive electrode of the VFB comprises electrochemically reactivating the positive electrode and the negative electrode.

3 . The method of claim 12 , wherein the step of simultaneously reconditioning the negative electrode and the positive electrode of the VFB comprises electrochemically reactivating the positive electrode and the negative electrode and the step of electrochemically reactivating the positive electrode and the negative electrode comprises applying an activation potential to the negative electrode for V II /V III oxidation-reduction and applying an activation potential to the positive electrode for V IV /V V oxidation-reduction.

4 . The method of claim 3 , wherein the activation potential of the positive electrode corresponds to the negative half-cell working potential and the activation potential of the negative electrode corresponds to the positive half-cell working potential.

5 . The method of claim 1 , wherein the step of simultaneously reconditioning the negative electrode and the positive electrode of the VFB comprises electrochemically reactivating the positive electrode and the negative electrode; the step of electrochemically reactivating the positive electrode and the negative electrode comprises applying an activation potential to the negative electrode for V II /V III oxidation-reduction and applying an activation potential to the positive electrode for V IV /V V oxidation-reduction; and wherein the step of applying the activation potential to the positive electrode and to the negative electrode comprises the steps of:
switching the positive half-cell and the negative half-cell electrodes of the VFB.

6 . The method of claim 5 , wherein the step of switching the positive half-cell and the negative half-cell electrodes comprises:
draining the positive half-cell into the positive reservoir of the VFB and draining the negative half-cell into the negative reservoir of the VFB; and connecting the negative reservoir to the positive half-cell and connecting the positive reservoir to the negative half-cell.

7 . The method of claim 56 , further comprising the step of:
disconnecting the positive reservoir from the positive half-cell and the negative reservoir from the negative half-cell after draining the positive half-cell and the negative half-cell.

8 . The method of claim 1 , wherein the step of simultaneously reconditioning the negative electrode and the positive electrode of the VFB comprises electrochemically reactivating the positive electrode and the negative electrode; the step of electrochemically reactivating the positive electrode and the negative electrode comprises applying an activation potential to the negative electrode for V II /V III oxidation-reduction and applying an activation potential to the positive electrode for V IV /V V oxidation-reduction; and the step of applying the activation potential to the positive electrode and to the negative electrode comprises the step of:
overdischarging the electrolyte at the negative electrode from V II /V III to at least V IV and overdischarging the electrolyte at the positive electrode from V IV /V V to at least V III while controlling the current through the cell or the potential at an electrode.

9 . The method of claim 8 , further comprising performing the step of overdischarging the electrolytes at the negative electrode and the positive electrode by preventing the pumping of the electrolytes of the VFB during a discharge cycle.

10 . The method of claim 8 , further comprising the step of re-establishing the state of charge, SoC, of the electrolyte in the positive half-cell and the electrolyte in the negative half-cell to the operating SoCs prior to restarting the operation of the VFB.

11 . The method of claim 8 , further comprising the step of re-establishing the state of charge, SoC, of the electrolyte in the positive half-cell and the electrolyte in the negative half-cell to the operating SoCs prior to restarting the operation of the VFB wherein the step of re-establishing the state of charge, SoC, of the electrolyte in the positive half-cell and in the negative half-cell to the operating SoCs comprises the step of pumping the electrolytes of the VFB prior to commencing a charging cycle of the VFB.

12 . The method of claim 8 wherein the step of operating the VFB for a number of charge and discharge cycles comprises operating the VFB for an initial controlled charging cycle.

13 . The method of claim 3 , wherein the step of applying the activation potential to the positive electrode and to the negative electrode comprises the step of:
overdischarging the electrolyte at the negative electrode from V II /V III to V III to V IV to V IV /V V and overdischarging the electrolyte at the positive electrode from V IV /V V to V IV to V III to V II /V III while controlling the current through the cell or the potential at an electrode.

14 . The method of claim 3 , wherein the step of applying the activation potential to the positive electrode and to the negative electrode comprises the step of:
overdischarging the electrolyte at the negative electrode from V II /V III to V III to V IV to V IV /V V and overdischarging the electrolyte at the positive electrode from V IV /V V to V IV to V III to V II /V III while controlling the current through the cell or the potential at an electrode and further comprising performing the step of overdischarging the electrolytes at the negative electrode and the positive electrode during the pumping of the electrolytes of the VFB.

15 . The method of claim 1 , wherein the step of reconditioning the VFB electrodes is performed prior to the first charge/discharge cycle of the battery.

16 . The method of claim 1 , wherein the step of reconditioning the VFB electrodes is performed after a number of cycles.

17 . The method of claim 1 , wherein the step of reconditioning the VFB electrodes is performed a number of cycles after a previous reconditioning.

18 . A system for improving the energy efficiency of a vanadium flow battery, VFB comprising:
means for simultaneously reconditioning the negative electrode and the positive electrode of the VFB.

Assignees

• Univ Limerick

Inventors

• Lynch Robert Patrick
• Quill Nathan
• Bourke Andrea
• Buckley Denis Noel

Classifications

• H02J7/865

  Battery or charger load switching, e.g. concurrent charging and load supply (H02J7/50 takes precedence) · CPC title

• H01M8/04753

  of fuel cell reactants · CPC title

• H01M8/188 Primary

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

• H02J7/0068

  Electricity · mapped topic

• H01M8/04186

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