ELECTRODE STRUCTURE OF FLOW BATTERY, FLOW BATTERY STACK, AND SEALING STRUCTURE FOR FLOW BATTERY STACK

• US 20190319274A1
• Filed: 11/03/2017
• Published: 10/17/2019
• Est. Priority Date: 11/09/2016
• Status: Active Grant

• Current Assignee: Dalian Rongke Power Co., Ltd.
• Original Assignee: Dalian Rongke Power Co., Ltd.
• Inventors: LIU, Shenglin, JIANG, Hongdong, ZHANG, Huamin, MA, Xiangkun, ZHANG, Tao, JIANG, Shan, YANG, Zhenkun, SUN, Dan, YI, Kuanrong
• Granted Patent: US 11,063,263 B2
• Time in Patent Office: Days
• CPC Class Codes: H01M 2004/021 Physical characteristics, e.g. porosity, surface area
• CPC Class Codes: H01M 4/75 Wires, rods or strips
• CPC Class Codes: H01M 4/861 with a gradient in the porosity
• CPC Class Codes: H01M 4/8636 with a gradient in another property than porosity H01M4/861 takes precedence
• CPC Class Codes: H01M 4/8657 layered
• CPC Class Codes: H01M 8/0273 with sealing or supporting means in the form of a frame
• CPC Class Codes: H01M 8/0276 Sealing means characterised by their form H01M8/0273 takes precedence
• CPC Class Codes: H01M 8/188 by recharging of redox couples containing fluids; Redox flow type batteries
• CPC Class Codes: H01M 8/2455 with liquid, solid or electrolyte-charged reactants
• CPC Class Codes: H01M 8/2483 characterised by internal manifolds
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

An electrode structure of a flow battery, a flow battery stack, and a sealing structure of the flow battery stack, wherein the density of the vertical tow in the electrode fiber is larger than the density of the parallel tow. In the electrode fiber per unit volume, the quantity ratio of the vertical tow to the parallel tow is at least 6:4. The electrode structure is composed of an odd number of layers of the electrode fibers, and the porosity of other layers is larger than the porosity of the center layer. The electrode structure is mainly composed of the vertical tows perpendicular to the surface of the electrode, so that, firstly, the contact area between the outer surface of the electrode and the adjacent component can be increased and the contact resistance can be reduced, secondly, the electrode is endowed with good mechanical properties, compared with the original structure, the contact resistance of such structure is reduced by 30%-50%; and the layers of the electrode have different thickness depending on the porosity, after compression, the layers with optimized thickness have a consistent porosity, this compressed uniform structure avoids uneven mass transfer phenomena when the electrolyte flows through the electrode, and reduces the concentration polarization of the battery and thereby improving the battery energy output under the given power.

Claims

1. An electrode structure of a flow battery, comprising an electrode fiber, characterized in that, a density of vertical tows in the electrode fiber is larger than a density of parallel tows.

2. The electrode structure of the flow battery according to claim 1, characterized in that, in the electrode fiber per unit volume, a quantity ratio of the vertical tows to the parallel tows is at least 6:

4.

3. The electrode structure of the flow battery according to claim 1, characterized in that, a number of layers of the electrode fiber is an odd number, and a porosity of the electrode fiber of each layer is increased outwardly from a center layer.

4. The electrode structure of the flow battery according to claim 3, characterized in that, the porosity of the electrode fiber of the center layer is 90-93%;

and the porosity of the electrode fiber of other layers is 93-96%.

5. The electrode structure of the flow battery according to claim 3, characterized in that, the number of layers of the electrode fiber is three, five or seven.

6. A flow battery stack, characterized in that, the flow battery stack is assembled by using the electrode structure according to claim 1, and after being compressed and assembled under a stack preload of 0.1-0.25 MPa, the porosity of the electrode fiber of each layer in the stack is compressed to 89-92%.

7. The flow battery stack according to claim 6, characterized in that, a difference between the porosity of the electrode fiber of each layer in the stack is less than 3%.

8. The flow battery stack according to claim 6, characterized in that, a total thickness of the electrode is 3-6 mm, a thickness of the electrode fiber of each layer gradually is decreased toward the center layer from an outside to an inside, and a thickness ratio of the other layers to the center layer is not less than 1.5:

1.

9. The flow battery stack according to claim 6, characterized in that, a surface of the electrode fiber of two side layers is a spinous or needlelike structure, and a height of the spinous or needlelike structure is different.

10. The flow battery stack according to claim 9, characterized in that, the spinous or needlelike structure is formed by the vertical tows perpendicular to a surface of the electrode, and a diameter of the vertical tows is 6-18 μ

m.

11. A sealing structure of the flow battery stack according to claim 6, characterized in that, the sealing structure of the flow battery stack comprises a sealing rubber, and the sealing rubber is formed by connecting a plurality of sealing gasket by a sealing wire, wherein the sealing gasket is provided with an electrolyte common flow channel hole, and one side of the sealing gasket provided with a compression deformation structure, and the other side of the sealing gasket provided with an annular convex structure.

12. The sealing structure of the flow battery stack according to claim 11, characterized in that, the sealing gasket is provided with at least two layers of the annular convex structures, wherein an inner diameter of the innermost annular convex structure is larger than or equal to an outer diameter of the electrolyte common flow channel hole.

13. The sealing structure of the flow battery stack according to claim 12, characterized in that, a cross-sectional shape of the annular convex structures of each layer is rectangle, semicircle or trapezoid.

14. The sealing structure of the flow battery stack according to claim 11, characterized in that, the compression deformation structure is a plurality of grooves.

15. The sealing structure of the flow battery stack according to claim 11, characterized in that, the sealing gasket is provided with at least one sealing gasket positioning structure, wherein a thickness of the sealing gasket positioning structure is 0.3-0.8 times the thickness of the sealing gasket.

16. The sealing structure of the flow battery stack according to claim 11, characterized in that, a Shore hardness of the sealing rubber is preferably 40-100.

17. The sealing structure of the flow battery stack according to claim 11, characterized in that, a compression ratio of the sealing gasket is 10-30%.

18. The sealing structure of the flow battery stack according to claim 11, characterized in that, the sealing structure of the flow battery stack further comprises an electrode frame, the electrode frame is provided with a wire sealing groove and a gasket sealing groove, and the sealing wire and the sealing gasket are respectively placed in the wire sealing groove and the gasket sealing groove, wherein a filling ratio of the sealing gasket to the gasket sealing groove is 90-95%, and a filling ratio of the sealing wire to the wire sealing groove is 90-95%.

19. The sealing structure of the flow battery stack according to claim 18, characterized in that, an connection area of the gasket sealing groove with the wire sealing groove is in close contact with the sealing gasket, and a size of the other areas of the gasket sealing groove is larger than the size of the sealing gasket.

20. The sealing structure of the flow battery stack according to claim 18, characterized in that, the sealing structure of the flow batter stack comprises two electrode frames, two sealing rubbers and one diaphragm;

a distance from the wire sealing grooves of the two electrode frames to an outer edge of the respective electrode frame is different, the sealing rubbers are placed in the sealing groove of the electrode frame, and the sealing gasket of the sealing rubber is provided with one side of the compression deformation structure in contact with the electrode frame and the other side is in contact with the diaphragm, sealing the diaphragm at the electrolyte common flow channel hole is to cover the electrolyte common flow channel hole of the diaphragm on an outermost annular convex structure of one of the sealing gaskets, wherein one side of the diaphragm is in contact with the sealing gasket of one of the sealing rubbers, and the other side is in contact with the sealing wire of another sealing rubber, and sealing the diaphragm at non-electrolyte common flow channel hole is the diaphragm is sealed by the sealing wire of the two misaligned sealing rubbers.