FLOWING ELECTROLYTE BATTERY MAINTENANCE BUS SYSTEM AND METHOD

• US 20150229141A1
• Filed: 08/07/2013
• Published: 08/13/2015
• Est. Priority Date: 08/08/2012
• Status: Abandoned Application

• Current Assignee: Redflow R&D Pty Ltd
• Original Assignee: Redflow R&D Pty Ltd
• Inventors: Winter, Alexander Rudolf
• Application Number:
  US14/419,753
• Publication Number:
  US 20150229141A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01M 12/085 Zinc-halogen cells or batteries
• CPC Class Codes: H02J 7/0014 Circuits for equalisation of charge between batteries
• CPC Class Codes: H02J 7/0019 using switched or multiplexed charge circuits
• CPC Class Codes: H02J 7/0069 Charging or discharging for charge maintenance, battery initiation or rejuvenation
• CPC Class Codes: H02J 7/342 The other DC source being a battery actively interacting with the first one, i.e. battery to battery charging with circuits for polarity protection H02J7/0034
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A flowing electrolyte battery system and a method of maintaining a flowing electrolyte battery system is provided. The flowing electrolyte battery system includes a power bus, a maintenance bus, and a plurality of flowing electrolyte batteries switchedly connected to the power bus or the maintenance bus. A bi-directional converter connects the maintenance bus and the power bus, and the bi-directional converter includes a step-up mode, for creating a positive potential difference between the maintenance bus and the power bus, and a step-down mode, for creating a negative potential difference between the maintenance bus and the power bus.

Claims

1. A flowing electrolyte battery system including:

a power bus;

a maintenance bus;

a plurality of flowing electrolyte batteries switchedly connected to the power bus or the maintenance bus; and

a bi-directional converter connecting the maintenance bus and the power bus,

wherein the bi-directional converter includes a step-up mode, for creating a positive potential difference between the maintenance bus and the power bus, and a step-down mode, for creating a negative potential difference between the maintenance bus and the power bus.

2. The flowing electrolyte battery system of claim 1, further including:

a bidirectional inverter connected to the power bus, for converting between direct current (DC) of the power bus and alternating current (AC) of an external power network.

3. The flowing electrolyte battery system of claim 1, further including a controller, the controller including:

a sensor, for receiving a measurement of a flowing electrolyte battery of the plurality of flowing electrolyte batteries; and

at least one output, for regulating a component of the system;

wherein the output is controlled according to the received measurement.

4. The flowing electrolyte battery system of claim 3, wherein the measurement includes at least one of a voltage and a resistance of a battery of the plurality of flowing electrolyte batteries.

5. The flowing electrolyte battery system of claim 4, wherein the measurement includes at least one of a voltage and a resistance of each battery of the plurality of flowing electrolyte batteries.

6. The flowing electrolyte battery system of claim 3, wherein the component of the system includes one of a switch, a pump of the battery and the bi-directional converter.

7. The flowing electrolyte battery system of claim 3, wherein the controller further includes:

a processor, coupled to the sensor and the output; and

a memory, coupled to the processor, including program code executable by the processor for performing maintenance procedures.

8. The flowing electrolyte battery system of claim 7, wherein the maintenance procedures include:

determining that a battery of the plurality of zinc-bromine batteries is fully charged;

disconnecting the battery from the power bus and turning off a zinc pump and a bromine pump of the battery;

periodically running the zinc pump while the battery is disconnected from the power bus; and

periodically reconnecting the battery to the power bus for recharging, wherein the zinc pump and the bromine pump are turned on during recharging.

9. The flowing electrolyte battery system of claim 7, wherein the maintenance procedures include:

connecting a battery to the maintenance bus;

discharging the battery until a first threshold criterion is reached;

short circuiting the battery until a second threshold criterion is reached;

recharging the battery; and

connecting the battery to the power bus.

10. The flowing electrolyte battery system of claim 7, wherein the maintenance procedures include balancing the State of Charge (SoC) of the batteries by:

determining a first SoC of a first battery of the plurality of flowing electrolyte batteries, wherein the first battery is connected to the power bus;

determining a second SoC of a second battery of the plurality of flowing electrolyte batteries, wherein the second battery is connected to the power bus and the first SoC is higher than the second SoC; and

performing one of;

connecting the first battery to the maintenance bus and discharging the first battery;

or

connecting the second battery to the maintenance bus and charging the second battery.

11. A method of maintaining a flowing electrolyte battery system, wherein the flowing electrolyte battery system includes a plurality of zinc-bromine batteries, each of the plurality of zinc-bromine batteries switchedly connected to a power bus and a maintenance bus, the method including:

determining that a battery of the plurality of zinc-bromine batteries is fully charged;

disconnecting the battery from the power bus and turning off a zinc pump and a bromine pump of the battery;

periodically running the zinc pump while the battery is disconnected from the power bus; and

periodically reconnecting the battery to the power bus for recharging, including turning on the zinc pump and the bromine pump during recharging.

12. The method of claim 11, further including:

connecting the battery to the maintenance bus;

discharging the battery until a first threshold criterion is reached;

short circuiting the battery until a second threshold criterion is reached;

recharging the battery; and

reconnecting the battery to the power bus.

13. The method of claim 12, wherein discharging the battery comprises creating a positive potential difference between the maintenance bus and the power bus by a direct current (DC)-DC converter.

14. The method of claim 12, wherein the battery is discharged at a constant current.

15. The method of claim 14, wherein the constant current is about 50 milliamperes per square centimetre of electrode.

16. The method of claim 12, wherein the first threshold criterion is about 0.05 volt per cell across the battery.

17. The method of claim 12, wherein the second threshold criterion is about 0 volt across the battery maintained for a period of about 30 minutes.

18. The method of claim 12, wherein recharging the battery comprises charging the battery using the maintenance bus.

19. The method of claim 18, wherein recharging the battery comprises creating a negative potential difference between the maintenance bus and the power bus by a direct current (DC)-DC converter and charging the battery to a specific SoC.

20. The method of claim 19, wherein the specific SoC comprises a SoC of another battery on the power bus.

21. The method of claim 12, wherein recharging the battery comprises charging the battery using the power bus.

22. The method of claim 11, further including:

determining a first SoC of a first battery of the plurality of zinc-bromine batteries, wherein the first battery is connected to the power bus;

determining a second SoC of a second battery of the plurality of zinc-bromine batteries, wherein the second battery is connected to the power bus, wherein the first SoC is higher than the second SoC; and

performing one of;

connecting the first battery to the maintenance bus and discharging the first battery;

or

connecting the second battery to the maintenance bus and charging the second battery.

23. A flowing electrolyte battery system including:

a power bus;

a maintenance bus;

a plurality of flowing electrolyte batteries switchedly connected to the power bus or the maintenance bus; and

a power converter connecting the maintenance bus and the power bus,

wherein the power converter is configurable to generate a potential difference between the power bus and the maintenance bus such that batteries that are connected to the maintenance bus are charged.

24. The flowing electrolyte battery system of claim 23, wherein the power converter is configurable to convert between an alternating current of an external power network or a direct current of the power bus to a direct current of the maintenance bus, and wherein an electrical load is used to discharge any batteries that are connected to the maintenance bus.