Battery cell structure for all-vanadium redox flow battery

Abstract

The utility model relates to the technical field of redox flow batteries, in particular to a battery cell structure for an all-vanadium redox flow battery, which comprises a pair of oppositely arranged polar plates, a diaphragm arranged between the two polar plates, and carbon cloth arranged between the polar plates and the diaphragm, the opposite end surfaces of the polar plates are provided with concave flow channels, and the graphite felt strips are embedded in the flow channels; the carbon cloth is located between the flow channel and the graphite felt strips, and the diaphragm is located between the two graphite felt strips. The branches and the runner ridges are arranged on the bipolar plate, and the carbon cloth electrodes are tightly attached to the surface of the bipolar plate by adopting the graphite felt strips, so that the contact resistance between the carbon cloth and the bipolar plate can be effectively reduced; the graphite felt strips are filled in the electrolyte flow channel, so that the influence on the pressure drop in the electrolyte flowing process is small, and the liquid resistance can be effectively reduced; and the graphite felt strip can also be used as a place where active substances in the electrolyte react, so that the efficiency of the battery can be further improved.

Description

Technical Field

[0001] The utility model relates to the technical field of liquid flow batteries, in particular to a battery core structure for an all-vanadium liquid flow battery. Background Art

[0002] All-vanadium liquid flow battery is a long-term energy storage battery, which mainly uses the conversion of vanadium in different valence states to convert electrical energy into chemical energy and then into electrical energy. Electrodes are the place where ions react. Most of the electrodes of commercial all-vanadium liquid flow batteries are graphite felt, which is thick, which makes it difficult to reduce the thickness of the battery cell. Carbon cloth also has the characteristics of graphite felt such as corrosion resistance, high temperature resistance, good stability, and high mechanical strength. It has the potential to be used as an electrode for all-vanadium liquid flow batteries. In addition, carbon cloth is thin, which can effectively reduce the thickness of the battery cell. However, carbon cloth has problems with large liquid resistance and contact resistance in actual application. Summary of the invention

[0003] The utility model aims to provide a battery core structure for an all-vanadium liquid flow battery, which reduces liquid resistance and contact resistance in a structure using carbon cloth as an electrode.

[0004] The utility model provides the following technical solutions:

[0005] A battery cell structure for an all-vanadium liquid flow battery comprises a pair of oppositely arranged pole plates, a diaphragm arranged between the two pole plates, and a carbon cloth arranged between the pole plates and the diaphragm; concave flow channels are arranged on opposite end faces of the pole plates, and the battery cell structure also comprises a graphite felt strip embedded in the flow channel; the carbon cloth is located between the flow channel and the graphite felt strip, and the diaphragm is located between the two graphite felt strips.

[0006] Preferably, the flow channel includes a plurality of parallel branches, and the graphite felt strips are embedded in the branches.

[0007] Preferably, a plurality of branches are arranged in an array perpendicular to the direction of electrolyte flow.

[0008] Preferably, the graphite felt strip and the branch are interference fit.

[0009] Preferably, a flow channel ridge is formed between adjacent branches, and the cross section of the flow channel ridge is triangular.

[0010] Preferably, the height of the flow channel ridge is 0.8-2 mm.

[0011] Preferably, the distance between two adjacent flow channel ridges is 2-4 mm.

[0012] Preferably, the gap between two flow channel ridges that are oppositely arranged and respectively located on the two electrode plates is equal to 20%-50% of the thickness of the carbon cloth.

[0013] Preferably, the end surfaces of the plurality of graphite felt strips away from the electrode plates where they are located are all located in the same horizontal plane and are higher than the top of the flow channel ridge.

[0014] Preferably, the height difference between the end surface of the graphite felt strip away from the electrode plate where it is located and the top of the flow channel ridge is 0-0.2 mm.

[0015] The beneficial effects of the utility model include at least:

[0016] 1. The utility model constructs branches and flow channel ridges on the bipolar plate and uses graphite felt strips to hold the carbon cloth electrode close to the surface of the plate, thereby effectively reducing the contact resistance between the carbon cloth and the bipolar plate.

[0017] 2. The graphite felt strips are filled in the electrolyte flow channel, which has little effect on the pressure drop during the flow of the electrolyte and can effectively reduce the liquid resistance.

[0018] 3. Graphite felt strips can also serve as a place for active substances in the electrolyte to react, which can further improve the efficiency of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A cross-sectional view of a battery cell structure according to an embodiment of the utility model;

[0020] Figure 2 A top view of a plate according to an embodiment of the utility model;

[0021] Figure 3 It is a schematic diagram of the assembly of multiple battery core structures of the utility model.

[0022] Description of Reference Numerals

[0023] In the above figure: 1. electrode plate; 11. rectangular groove; 12. positive electrode electrolyte inlet; 13. negative electrode electrolyte inlet; 14. negative electrode electrolyte outlet; 15. positive electrode electrolyte outlet; 2. diaphragm; 3. carbon cloth; 4. flow channel; 41. liquid inlet; 42. branch; 43. liquid outlet; 5. graphite felt strip; 6. flow channel ridge; 61. edge. DETAILED DESCRIPTION

[0024] In order to make the technical problems, technical solutions and beneficial effects solved by the utility model more clearly understood, the utility model is further described below in conjunction with the accompanying drawings and embodiments. It should be understood that the embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0025] refer to Figure 1 , Figure 2A battery cell structure for an all-vanadium liquid flow battery includes a pair of electrode plates 1, a diaphragm 2 arranged between the two electrode plates 1, a carbon cloth 3 arranged between the electrode plates 1 and the diaphragm 2, and a plurality of graphite felt strips 5 arranged between the carbon cloth 3 and the diaphragm 2.

[0026] refer to Figure 1 , Figure 2 The electrode plate 1 is in the shape of a rectangular parallelepiped, and a rectangular groove 11 is provided at the center of the front side of the electrode plate 1. A plurality of flow channel ridges 6 are integrally formed on the bottom surface of the rectangular groove 11. The cross section of the flow channel ridge 6 is an equilateral triangle. The length of the perpendicular line of the equilateral triangle is less than the depth of the rectangular groove 11, and the difference between the two is 0.8-2 mm. One side of the equilateral triangle coincides with the bottom surface of the rectangular groove 11. The projection of the flow channel ridge 6 from top to bottom in the rectangular groove 11 is a rectangle. The distance between the adjacent sides of the two rectangles is 2-4 mm. The plurality of flow channel ridges 6 are parallel to each other and to the flow direction of the electrolyte (the flow direction of the electrolyte is shown by the arrow).

[0027] refer to Figure 1 , Figure 2 , the electrode plate 1 is provided with a flow channel 4, the flow channel 4 includes branches 42 formed between two adjacent flow channel ridges 6 and between the flow channel ridges 6 and the side walls of the rectangular groove 11, and a plurality of branches 42 are also distributed in an array and connected in parallel. The flow channel 4 also includes an inlet channel 41 and an outlet channel 43 opened on the front of the electrode plate 1 and connected to the rectangular groove 11, and the electrode plate 1 is provided with a positive electrode electrolyte inlet 12, a negative electrode electrolyte inlet 13, a negative electrode electrolyte outlet 14, and a positive electrode electrolyte outlet 15 connected to the flow channel 4.

[0028] refer to Figure 1 , Figure 2 The thickness of the carbon cloth 3 is 1 mm, the flow channel ridge 6 includes an edge 61 away from its integrally formed electrode plate 1. In a battery cell structure, after the two electrode plates 1 are pressed against each other, a gap is formed between the edges 61 on the two opposite flow channel ridges 6, and the gap is 0.2-0.5 mm.

[0029] refer to Figure 1 , Figure 2 The cross section of the branch 42 is a trapezoid. Except for the two outermost branches 42, the cross sections of the other branches 42 are isosceles trapezoids. The cross section of the graphite felt strip 5 corresponds to the cross section of the branch 42, and the graphite felt strip 5 and the branch 42 are interference fit. The length of the graphite felt strip 5 is equal to the length of the branch 42. The graphite felt strip 5 is embedded in the branch 42, and the end surface of the graphite felt strip 5 away from the electrode plate 1 where it is located is located in the same horizontal plane and higher than the edge 61 of the flow channel ridge 6, and the height difference between the two is 0-0.2mm.

[0030] refer to Figure 3The battery stack is composed of a plurality of battery cell structures. The electrode plate 1 includes a monopolar plate 1 with a flow channel 4 on one side and a bipolar plate 1 with flow channels 4 on both sides. A battery stack structure is formed between two adjacent electrode plates 1.

[0031] The implementation principle of an electrode frame assembly in the embodiment of the present application is:

[0032] 1. Place the carbon cloth 3 on the surface of the electrode plate 1 where the flow channel 4 is opened. The carbon cloth 3 is closely attached to the branch 42 and the flow channel ridge 6 and is completely attached to the electrode plate 1 .

[0033] 2. The graphite felt strip 5 is embedded in the branch 42 . Under the action of elastic force, the graphite felt strip 5 is pressed against the side wall of the branch 42 , and the carbon cloth 3 is clamped between the branch 42 and the graphite felt strip 5 .

[0034] 3. Assemble multiple pole plates 1 in sequence, and clamp the diaphragm 2 between two pole plates 1 that are close to each other.

[0035] Although the preferred embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms of specific changes without departing from the scope of protection of the invention and the claims, all of which fall within the scope of protection of the present invention.

Claims

1. A battery cell structure for an all-vanadium liquid flow battery, characterized in that: The invention comprises a pair of electrode plates (1) arranged opposite to each other, a diaphragm (2) arranged between the two electrode plates (1), and a carbon cloth (3) arranged between the electrode plates (1) and the diaphragm (2); the electrode plates (1) are provided with concave flow channels (4) on the opposite end faces thereof, and also comprise graphite felt strips (5) embedded in the flow channels (4); the carbon cloth (3) is located between the flow channels (4) and the graphite felt strips (5), and the diaphragm (2) is located between the two graphite felt strips (5).

2. The battery core structure for all-vanadium redox flow battery according to claim 1, characterized in that: The flow channel (4) comprises a plurality of parallel branches (42), and the graphite felt strips (5) are embedded in the branches (42).

3. The battery core structure for all-vanadium redox flow battery according to claim 2, characterized in that: A plurality of the branches (42) are arranged in an array perpendicular to the direction of electrolyte flow.

4. The battery core structure for all-vanadium redox flow battery according to claim 3, characterized in that: The graphite felt strip (5) and the branch channel (42) are in interference fit.

5. The battery core structure for all-vanadium redox flow battery according to claim 4, characterized in that: A flow channel ridge (6) is formed between adjacent branches (42), and the cross section of the flow channel ridge (6) is triangular.

6. The battery core structure for all-vanadium redox flow battery according to claim 5, characterized in that: The height of the flow channel ridge (6) is 0.8-2 mm.

7. The battery core structure for all-vanadium redox flow battery according to claim 6, characterized in that: The distance between two adjacent flow channel ridges (6) is 2-4 mm.

8. The battery core structure for all-vanadium redox flow battery according to claim 7, characterized in that: The gap between two flow channel ridges (6) that are arranged opposite to each other and are respectively located on two electrode plates (1) is equal to 20% to 50% of the thickness of the carbon cloth (3).

9. The battery core structure for all-vanadium redox flow battery according to claim 8, characterized in that: The end surfaces of the plurality of graphite felt strips (5) away from the electrode plate (1) on which they are located are all located on the same horizontal plane and are higher than the top of the flow channel ridge (6).

10. The battery core structure for all-vanadium redox flow battery according to claim 9, characterized in that: The height difference between the end surface of the graphite felt strip (5) away from the electrode plate (1) on which it is located and the top of the flow channel ridge (6) is 0-0.2 mm.

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