Redox Flow Battery System for Distributed Energy Storage

• US 20100003545A1
• Filed: 07/06/2009
• Published: 01/07/2010
• Est. Priority Date: 07/07/2008
• Status: Active Grant

• Current Assignee: EnerVault Corporation
• Original Assignee: EnerVault Corporation
• Inventors: Horne, Craig Richard, Hickey, Darren B., Kinoshita, Kim
• Granted Patent: US 7,820,321 B2
• Time in Patent Office: Days
• US Class Current: 429/12
• CPC Class Codes: B60L 2200/26 Rail vehicles
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 50/64 Constructional details of batteries specially adapted for electric vehicles
• CPC Class Codes: B60L 53/302 Cooling of charging equipment
• CPC Class Codes: B60L 53/51 Photovoltaic means
• CPC Class Codes: B60L 53/52 Wind-driven generators
• CPC Class Codes: B60L 53/54 Fuel cells
• CPC Class Codes: H01M 8/188 by recharging of redox couples containing fluids; Redox flow type batteries
• CPC Class Codes: H01M 8/20 Indirect fuel cells, e.g. fuel cells with redox couple being irreversible H01M8/18 takes precedence
• CPC Class Codes: H01M 8/2455 with liquid, solid or electrolyte-charged reactants
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles
• CPC Class Codes: Y10T 29/49108 Electric battery cell making

Abstract

A large stack redox flow battery system provides a solution to the energy storage challenge of many types of renewable energy systems. Independent reaction cells arranged in a cascade configuration are configured according to state of charge conditions expected in each cell. The large stack redox flow battery system can support multi-megawatt implementations suitable for use with power grid applications. Thermal integration with energy generating systems, such as fuel cell, wind and solar systems, further maximize total energy efficiency. The redox flow battery system can also be scaled down to smaller applications, such as a gravity feed system suitable for small and remote site applications.

Claims

1. A redox flow battery energy storage system, comprising:

a redox flow battery stack assembly comprising;

an array of cells layers each comprising a plurality of cells arranged along a reactant flow path through the layer, wherein each one of the plurality of cells is configured according to its position along the reactant flow path.

2. The redox flow battery system of claim 1, wherein each of the plurality of cells is configured with a separator membrane selected so that a cell located at a first end of the reactant flow path has lesser porosity than the separator membrane in a cell located at a second end of the reactant flow path, wherein the redox flow battery energy storage system is configured so that reactant flows through the redox flow battery stack assembly from the first end to the second end for discharging or from the second end to the first end for charging.

3. The redox flow battery system of claim 2, wherein each of the plurality of cells is configured with an electrode material having a charge catalyst on its surface with a loading selected so that the cell located at the first end of the reactant flow path has electrode material with a greater charge catalyst loading than the electrode material in the cell located at the second end of the reactant flow path, wherein the redox flow battery energy storage system is configured so that reactant flows through the redox flow battery stack assembly from the first end to the second end for discharging or from the second end to the first end for charging.

4. The redox flow battery system of claim 3, wherein each one of the plurality of cells is configured with an electrode material having a charge catalyst on its surface with an activity selected so that a cell located at the first end of the reactant flow path has electrode material with a greater charge catalyst activity than the electrode material in the cell located at the second end of the reactant flow path, wherein the redox flow battery energy storage system is configured so that reactant flows through the redox flow battery stack assembly from the first end to the second end for discharging or from the second end to the first end for charging.

5. The redox flow battery system of claim 4, wherein each one of the plurality of cells is configured so that the cell located at the first end of the reactant flow path exhibits less reactant mass transport rate than the separator membrane in the cell located at the second end of the reactant flow path, wherein the redox flow battery energy storage system is configured so that reactant flows through the redox flow battery stack assembly from the first end to the second end for discharging or from the second end to the first end for charging.

6. The redox flow battery system of claim 5, wherein the redox flow battery stack assembly is configured so that the cell located at the first end of the reactant flow path exhibits a greater charge reactant mass transport rate than the cell located at the second end of the reactant flow path, wherein the redox flow battery energy storage system is configured so that reactant flows through the redox flow battery stack assembly from the first end to the second end for discharging or from the second end to the first end for charging.

7. The redox flow battery system of claim 6, wherein the redox flow battery stack assembly further comprises a heat exchanger configured so that reactant entering the cell located at the first end of the reactant flow path is at higher temperature than reactant entering the cell located at the second end of the reactant flow path, wherein the redox flow battery energy storage system is configured so that reactant flows through the redox flow battery stack assembly from the first end to the second end for discharging or from the second end to the first end for charging.

8. The redox flow battery system of claim 1, wherein each cell within each stack cell layer is configured as a planar components assembled in a stack, comprising:

a first bipolar frame, wherein the first bipolar frame is electrically insulating, except for the active area of the cell;

a first electrode material positioned adjacent to the first bipolar frame;

a separator membrane positioned adjacent to the first electrode material;

a second electrode material positioned adjacent to the separator membrane; and

a second bipolar frame positioned adjacent to the second electrode material, wherein the second bipolar frame is electrically insulating, except for the active area of the cell.

9. The redox flow battery system of claim 1, wherein the separator membrane is sealed around its edges.

10. The redox flow battery system of claim 1, further comprising four electrolyte storage tanks fluidically coupled to the redox flow battery stack assembly and configured so that a first tank holds charge catholyte, a second tank holds discharged catholyte, a third tank holds charge anolyte and a fourth tank holds discharge anolyte.

11. The redox flow battery system of claim 1, further comprising electrolyte storage tanks fluidically coupled to the redox flow battery stack assembly, the electrolyte storage tanks comprising a heat exchanger configured to heat the electrolyte to a range of about 40°

C. to about 65°

C.

12. The redox flow battery system of claim 1, further comprising:

a cylindrical support structure encompassing the redox flow battery stack assembly;

a first catholyte tank positioned within the cylindrical support structure on a first side of the redox flow battery stack assembly;

a first anolyte tank positioned within the cylindrical support structure on the first side of the redox flow battery stack assembly;

a second catholyte tank positioned within the cylindrical support structure on a second side of the redox flow battery stack assembly;

a second anolyte tank positioned within the cylindrical support structure on the second side of the redox flow battery stack assembly; and

piping fluidically coupling the first catholyte tank to the redox flow battery stack assembly and to the second catholyte tank, and coupling the first anolyte tank to the redox flow battery stack assembly and to the second anolyte tank,

wherein the piping and the redox flow battery stack assembly are configured so that charging of anolyte and catholyte reactants occurs when the first side of the redox flow battery stack assembly is up and discharging of anolyte and catholyte reactants occurs when the first side of the redox flow battery stack assembly is down.

13. The redox flow battery system of claim 12, further comprising:

at least two rollers supporting the cylindrical support structure; and

a drive mechanism coupled to one of the at least two rollers,

wherein the at least two rollers and the drive mechanism are configured to enable rotation of the cylindrical support structure by rotating the hand crank.

14. The redox flow battery system of claim 1, further comprising:

a reactant storage tank fluidically coupled to the redox flow battery stack assembly, the reactant storage tank comprising a tank separator configured to inhibit mixing of charged reactant with discharged reactant.

15. The redox flow battery system of claim 14, wherein the tank separator is buoyant, includes a valve mechanism which when opened allows reactant to flow through the tank separator, and is configured within the reactant storage tank so that when the valve mechanism is closed and discharged reactant enters the tank on top of the tank separator mixing of charged reactant with discharged reactant is inhibited, and when the valve mechanism is opened the tank separator will float to a top surface of the reactant.

16. The redox flow battery system of claim 14, wherein the tank separator is positioned vertically within the reactant storage tank and the reactant storage tank and the tank separator are configured so that the tank separator moves as reactant is pumped into the reactant storage tank on one side of the tank separator and is drawn out of the reactant storage tank from the other side of the tank separator so that mixing of charged reactant with discharged reactant is inhibited.

17. An electrical power system, comprising:

a source of electrical power; and

a redox flow battery system configured to receive electrical power from the source of electrical power and provide electrical power to an electrical load, the redox flow battery system comprising;

a first tank for storing a catholyte reactant;

a second tank for storing an anolyte reactant; and

a first redox flow battery stack assembly comprising;

an array of cells layers each comprising a plurality of cells arranged along a reactant flow path through the cell layers, the flow path having a first end and a second end, wherein each one of the plurality of cells is configured according to its position along the reactant flow path.

18. The electrical power system of claim 17, further comprising a heat exchanger configured to heat reactant, wherein the source of electrical power comprises a cooling system that outputs hot fluid and the heat exchanger is configured to use hot fluid from the electrical power source cooling system to heat reactant flowing through the first redox flow battery stack to a range of about 40°

C. to about 65°

C.

19. The electrical power system of claim 17, further comprising a heat exchanger configured to heat reactant, wherein the electrical load comprises a cooling system that outputs hot fluid and the heat exchanger is configured to use hot fluid from the load cooling system to heat reactant stored in the tanks to about 40 to 65°

C.

20. The electrical power system of claim 17, further comprising:

a source of geothermal energy that outputs hot water; and

a heat exchanger configured to heat reactant,

wherein the heat exchanger is configured to use hot water from the geothermal system to heat reactant to a range of about 40°

C. to about 65°

C.

21. The electrical power system of claim 17, further comprising a heat exchanger configured to heat reactant, wherein:

the source of electrical power comprises a wind turbine having a cooling system; and

the heat exchanger is configured to receive a fluid from the wind turbine cooling system.

22. The electrical power system of claim 17, further comprising a heat exchanger configured to heat reactant, wherein:

the source of electrical power comprises a solar energy conversion system having a cooling system;

the heat exchanger is configured to receive a fluid from the solar energy conversion system cooling system.

23. The electrical power system of claim 17, wherein:

the source of electrical power comprises a fuel cell.

24. The electrical power system of claim 17, wherein the electrical load is selected from the group of an electric vehicle charging system, a data center, a manufacturing center and an inverter electrically coupled to a utility grid.

25. The electrical power system of claim 17, wherein:

the redox flow battery system further comprises a second redox flow battery stack assembly comprising an array of cell layers each comprising a plurality of cells arranged along a reactant flow path through the cell layers, the flow path having a first end and a second end, wherein each one of the plurality of cells is configured according to its position along the reactant flow path;

the first redox flow battery stack assembly is connected to the source of electrical power and is configured to charge catholyte and anolyte reactants; and

the second redox flow battery stack assembly is connected to the electrical load and is configured to discharge catholyte and anolyte to provide electrical power to the electrical load.

26. The electrical power system of claim 17, wherein the first tank and the second tank each comprise a tank separator configured to inhibit mixing of charged reactant with discharged reactant.

27. The electrical power system of claim 26, wherein each tank separator is buoyant, includes a valve mechanism which when opened allows reactant to flow through the tank separator, and is configured within the respective first or second tank so that when the valve mechanism is closed mixing of charged reactant with discharged reactant is inhibited and when the valve mechanism is opened the tank separator will float to a top surface of the reactant.

28. The electrical power system of claim 26, wherein each tank separator is positioned vertically within the respective first or second tank and the respective first or second tank and its respective tank separator are configured so that the tank separator moves as reactant is pumped into the respective first or second tank on one side of the tank separator and is drawn out of the respective first or second tank from the other side of the tank separator so that mixing of charged reactant with discharged reactant is inhibited.

29. The electrical power system of claim 17, further comprising:

a third tank for storing discharged catholyte reactant; and

a fourth tank for storing discharged anolyte reactant,

wherein the system is configured to flow charged catholyte from the first tank through the first redox flow battery stack assembly and into the third tank and flow charged anolyte from the second tank through the first redox flow battery stack assembly and into the fourth tank while operating in discharge mode.

30. The electrical power system of claim 17, further comprising:

a third tank for storing discharged catholyte and anolyte reactants,

wherein the system is configured to flow charged catholyte from the first tank through the first redox flow battery stack assembly and into the third tank and flow charged anolyte from the second tank through the first redox flow battery stack assembly and into the third tank while operating in discharge mode, and to flow electrolytes from the third tank through the first redox flow battery stack assembly and into each of the first and second tanks while operating in charge mode.

31. The electrical power system of claim 17, wherein the redox flow battery system is configured to operate with the catholyte reactant and the anolyte reactant flowing in the same direction in both charge mode and discharge mode.