Methods and system for redox flow battery idle state

Patent metadata

Field	Value
Publication number	US-2023253584-A1
Application number	US-202318301935-A
Country	US
Kind code	A1
Filing date	Apr 17, 2023
Priority date	May 15, 2020
Publication date	Aug 10, 2023
Grant date	—

Abstract

Methods and systems are provided for a redox flow battery system. In one example, the redox flow battery system includes a power module, an electrolyte pump, and a power control system. The power control system may include instructions to switch the redox flow battery system to an idle mode, activate an electrolyte pump when a first threshold period of time elapses, deactivate the electrolyte pump when a second threshold period of time elapses, and drain, purge, and refill one or more electrode compartments when a third threshold period of time elapses.

First claim

1 . A redox flow battery system, comprising:
a power module comprising a plurality of redox flow battery cell stacks, each of the plurality of redox flow battery cell stacks comprising a redox flow battery cell; an electrolyte pump capable of delivering electrolyte from an electrolyte tank to the power module; and a power control system with a controller storing executable instructions in non-transitory memory, the instructions executable to:
switch the redox flow battery system to an idle mode, wherein the idle mode includes operation of the redox flow battery system outside of a charging mode and outside of a discharging mode;
initiate an off cycle timer and a drain timer concurrently;
activate the electrolyte pump while the redox flow battery system is in the idle mode to circulate electrolyte through one or more electrode compartments of the redox flow battery system when an off cycle threshold period of time monitored by the off cycle timer elapses;
deactivate the electrolyte pump while the redox flow battery system is in the idle mode when an on cycle threshold period of time monitored by an on cycle timer elapses, the on cycle timer initiated when the off cycle threshold period of time elapses; and
responsive to elapsing of a drain threshold period of time monitored by the drain timer while the redox flow battery system is still in the idle mode,
completely drain the electrolyte from the one or more electrode compartments of the redox flow battery system while the redox flow battery system in in the idle mode;
purge the drained one or more electrode compartments with a gas; and
refill the purged and drained one or more electrode compartments with fresh electrolyte;
wherein the drain threshold period of time is longer than the off cycle threshold period of time.

2 . The redox flow battery system of claim 1 , wherein the electrolyte is completely drained from the one or more electrode compartments by opening a drain valve of the one or more electrode compartments.

3 . The redox flow battery system of claim 2 , wherein the drain valve is closed when the one or more electrode compartments are flushed with a target volume of the gas, and wherein the gas is hydrogen or argon.

4 . The redox flow battery system of claim 1 , wherein a vacuum is formed in the one or more electrode compartments when the one or more electrode compartments are drained, and wherein the gas is drawn into the one or more electrode compartments by the vacuum.

5 . The redox flow battery system of claim 1 , wherein the redox flow battery system is in the idle mode when a power set point of the redox flow battery system is zero.

6 . The redox flow battery system of claim 1 , wherein power electronics of the redox flow battery system are deactivated when the redox flow battery system is in the idle mode.

7 . The redox flow battery system of claim 1 , wherein an electrolyte temperature of the redox flow battery system is reduced when the redox flow battery system is in the idle mode, and wherein the electrolyte temperature is reduced by decreasing a heater set point.

8 . The redox flow battery system of claim 7 , wherein the electrolyte temperature is reduced to below an idle threshold temperature, and wherein the idle threshold temperature is a temperature below which a solubility and/or a stability of electrolyte salts of the electrolyte is decreased.

9 . The redox flow battery system of claim 7 , wherein the electrolyte temperature is reduced but maintained at or above an idle threshold temperature, and wherein the idle threshold temperature is a temperature below which a solubility and/or a stability of electrolyte salts of the electrolyte is decreased.

10 . The redox flow battery system of claim 1 , wherein the drain threshold period of time is longer than the off cycle threshold period of time and the on cycle threshold period of time combined.

Assignees

• Ess Technology Inc

Inventors

• Song Yang
• Mcdonald Timothy J
• Fisher Kenneth

Classifications

• H01M8/04283 Primary

  Supply means of electrolyte to or in matrix-fuel cells · CPC title

• H01M8/04298

  Processes for controlling fuel cells or fuel cell systems · CPC title

• H01M8/188 Primary

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

• H01M8/04119

  with simultaneous supply or evacuation of electrolyte; Humidifying or dehumidifying · CPC title

• Y02E60/50

  Fuel cells · CPC title