Methods and systems for operating redox flow battery

Patent metadata

Field	Value
Publication number	US-2023343980-A1
Application number	US-202318179262-A
Country	US
Kind code	A1
Filing date	Mar 6, 2023
Priority date	Apr 26, 2022
Publication date	Oct 26, 2023
Grant date	—

Abstract

Systems and methods are provided for a redox flow battery. In one example, a method of operating a redox flow battery includes charging the redox flow battery, including supplying a pulsed power signal to the redox flow battery in response to the redox flow battery state of charge (SOC) decreasing below a lower threshold redox flow battery SOC, wherein supplying the pulsed power signal includes supplying a pulse-width-modulated (PWM) charging voltage signal to the redox flow battery, the PWM charging voltage signal fluctuating between an upper threshold charging voltage and an open circuit voltage (OCV).

First claim

1 . A method of operating a redox flow battery, comprising:
charging the redox flow battery, including supplying a pulse charging signal to the redox flow battery in response to a redox flow battery state of charge (SOC) decreasing below a lower threshold redox flow battery SOC, wherein supplying the pulse charging signal includes supplying a pulse-width-modulated (PWM) charging voltage signal to the redox flow battery, the PWM charging voltage signal fluctuating between an upper threshold charging voltage and an open circuit voltage (OCV).

2 . The method of claim 1 , further comprising, discharging the redox flow battery, including supplying a pulsed discharging signal from the redox flow battery, wherein supplying the pulsed discharging signal includes supplying a PWM discharging voltage signal from the redox flow battery, the PWM discharging voltage signal fluctuating between an upper threshold discharging voltage and the OCV.

3 . The method of claim 2 , wherein the upper threshold charging voltage changes with the redox flow battery SOC, and wherein charging the redox flow battery further includes adjusting a charging current to maintain the pulse charging signal at a threshold charging power while the PWM charging voltage signal is at the upper threshold charging voltage.

4 . The method of claim 3 , wherein the upper threshold discharging voltage changes with the redox flow battery SOC, and wherein discharging the redox flow battery further includes adjusting a discharging current to maintain the pulsed discharging signal at a threshold discharging power while the PWM discharging voltage signal is at the upper threshold discharging voltage.

5 . The method of claim 2 , wherein the PWM charging voltage signal and the PWM discharging each include a duty cycle between a lower threshold charging duty cycle and an upper threshold charging duty cycle.

6 . A redox flow battery system, comprising:
a power module, including a redox flow battery, an electrolyte subsystem fluidly coupled to the redox flow battery, and a controller, including executable instructions stored in non-transitory memory thereon to:
charge the redox flow battery, including to pulse charge the redox flow battery in response to a redox flow battery state of charge (SOC) decreasing below a lower threshold redox flow battery SOC, wherein to pulse charge includes to supply a pulse-width-modulated (PWM) charging voltage signal to the redox flow battery, the PWM charging voltage signal fluctuating between an upper threshold charging voltage and an open circuit voltage (OCV).

7 . The redox flow battery system of claim 6 , wherein the executable instructions further include to discharge the redox flow battery, including to pulse discharge the redox flow battery responsive to the redox flow battery SOC being greater than an upper threshold redox flow battery SOC while an electrical load is coupled to the redox flow battery, wherein to pulse discharge includes to supply a PWM discharging voltage signal from the redox flow battery, the PWM discharging voltage signal fluctuating between an upper threshold discharging voltage and the OCV.

8 . The redox flow battery system of claim 7 , wherein instructions to charge the redox flow battery further include to supply a continuous charging voltage signal to the redox flow battery in response to the redox flow battery SOC increasing above a continuous charging threshold redox flow battery SOC, the continuous charging threshold redox flow battery SOC greater than the lower threshold redox flow battery SOC.

9 . The redox flow battery system of claim 8 , wherein the power module includes a plurality of redox flow battery cell stacks, each redox flow battery cell stack including one or more redox flow battery, and the executable instructions further include to supply the PWM charging voltage signal or the continuous charging voltage signal to charge a first of the plurality of redox flow battery cell stacks, while supplying the PWM charging voltage signal or the continuous charging voltage signal to charge a second of the plurality of redox flow battery cell stacks.

10 . The redox flow battery system of claim 8 , wherein instructions to discharge the redox flow battery further include to supply a continuous discharging voltage signal from the redox flow battery in response to the redox flow battery SOC decreasing below a continuous discharging threshold redox flow battery SOC, the continuous discharging threshold redox flow battery SOC less than the upper threshold redox flow battery SOC.

11 . The redox flow battery system of claim 10 , wherein the executable instructions further include to increase the continuous discharging threshold redox flow battery SOC responsive to a plating efficiency of the redox flow battery decreasing below a threshold plating efficiency and to lower the continuous discharging threshold redox flow battery SOC responsive to a voltaic efficiency of the redox flow battery decreasing below a threshold voltaic efficiency.

12 . The redox flow battery system of claim 10 , wherein the executable instructions further include to reduce the continuous charging threshold redox flow battery SOC responsive to a plating efficiency of the redox flow battery decreasing below a threshold plating efficiency and to increase the continuous charging threshold redox flow battery SOC responsive to a voltaic efficiency of the redox flow battery decreasing below a threshold voltaic efficiency.

13 . A method of operating a redox flow battery, comprising:
in response to a redox flow battery SOC decreasing below a lower threshold redox flow battery SOC, pulse charging the redox flow battery, and in response to the redox flow battery SOC increasing above an upper threshold redox flow battery SOC, pulse discharging the redox flow battery.

14 . The method of claim 13 , wherein pulse charging the redox flow battery includes supplying a pulse charging power signal to charge the redox flow battery, and oscillating the pulse charging power signal between a lower threshold charging power and an upper threshold charging power.

15 . The method of claim 14 , wherein the lower threshold charging power is equal to an open circuit voltage of the redox flow battery.

16 . The method of claim 14 , wherein the upper threshold charging power is 50 kW and the upper threshold discharging power is −10 kW.

17 . The method of claim 14 , wherein pulse charging the redox flow battery includes pulse charging with a pulse-width-modulated (PWM) power signal, the PWM power signal having a duty cycle between a lower threshold duty cycle and an upper threshold duty cycle.

18 . The method of claim 13 , wherein pulse discharging the redox flow battery includes supplying a pulse discharging power signal to discharge the redox flow battery, and oscillating the pulse discharging power signal between a lower threshold discharging power and an upper threshold discharging power.

19 . The method of claim 13 , wherein pulse charging the redox flow battery includes pulse charging the redox flow battery above a threshold charging current density.

20 . The method of claim 13 , wherein pulse charging the redox flow battery includes pulse discharging the redox flow battery below a threshold discharging current density.

Assignees

• Ess Technology Inc

Inventors

• Song Yang
• Evans Craig
• Thompson Brady

Classifications

• H01M8/0494

  of fuel cell stacks · CPC title

• H01M8/0491

  of fuel cell stacks · CPC title

• H01M8/0488

  of fuel cell stacks · CPC title

• H01M8/04559

  of fuel cell stacks · CPC title

• H01M8/188 Primary

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