An electrode frame structure for a vanadium redox flow battery

Abstract

The application belongs to the technical field of liquid flow battery energy storage, and particularly relates to a full-vanadium liquid flow battery electrode frame structure which comprises an electrode frame, the electrode frame is a rectangular flat plate structure, through holes are arranged at edges close to four corners of the electrode frame, the four through holes are respectively used as electrolyte inlet and outlet through holes, a hollow rectangular middle through hole capable of accommodating a porous electrode is arranged at the middle of the rectangular flat plate of the electrode frame, electrolyte inlet and outlet main flow channels are arranged on one side surface of the electrode frame, and the electrolyte inlet and outlet main flow channels are close to the upper and lower edges of the electrode frame. In the application, PVC (polyvinyl chloride) is selected as the material of the electrode frame, the electrode frame is easy to process, electrolyte inlet and outlet auxiliary flow channels are distributed on the other two edges of the electrode frame, the electrolyte inlet and outlet auxiliary flow channels are respectively arranged in a serpentine manner on the electrode frame, the flow path of the electrolyte is greatly increased, and the flow resistance in the battery is increased.

Description

Technical Field

[0001] This invention relates to the field of flow battery energy storage technology, and in particular to an electrode frame structure for an all-vanadium redox flow battery. Background Technology

[0002] Vanadium redox flow batteries are a high-efficiency, high-stability, and long-life flow battery energy storage technology, mainly used in grid peak shaving, and renewable energy power generation such as wind and solar power. With the increasing demand for energy storage, improving the power density and stability of vanadium redox flow batteries is of paramount importance.

[0003] As the number of cells in a fuel cell stack increases, the impact of leakage current is amplified due to the presence of shared flow channels within the stack, limiting both coulombic efficiency and stability. Research has shown that increasing the internal flow resistance or lengthening the shared flow channels can effectively suppress the impact of leakage current. Therefore, appropriately increasing the electrolyte flow resistance within the stack can mitigate the effects of leakage current caused by stack enlargement, thereby improving battery coulombic efficiency and extending battery life.

[0004] There are no suitable technical means in the present technology to increase the flow resistance of the electrolyte inside the stack, thus failing to increase the flow path of the electrolyte and affect its service life. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies that lack suitable technical means to improve the flow resistance of the electrolyte inside the battery stack, thus failing to increase the flow path of the electrolyte and affecting its service life. Therefore, this invention proposes an electrode frame structure for a full vanadium redox flow battery.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A vanadium redox flow battery electrode frame structure includes an electrode frame, which is a rectangular plate structure. Through holes are provided near the four corners of the electrode frame, serving as an electrolyte inlet and an electrolyte outlet, respectively. A hollow rectangular central through hole, capable of accommodating a porous electrode, is provided in the center of the rectangular plate of the electrode frame. An electrolyte inlet main channel and an electrolyte outlet main channel are provided on one side surface of the electrode frame, located near the upper and lower edges of the electrode frame. The electrolyte inlet main channel is connected to the electrolyte inlet through hole, and the electrolyte outlet main channel is connected to the electrolyte outlet through hole.

[0008] Preferably, the surfaces of the other two sides of the electrode frame are respectively provided with an electrolyte inlet secondary channel and an electrolyte outlet secondary channel, the electrolyte inlet secondary channel being connected to the electrolyte inlet main channel, and the electrolyte outlet secondary channel being connected to the electrolyte outlet main channel.

[0009] Preferably, the surface of the electrode frame near the upper and lower sides of the through hole in the middle of the rectangle is provided with an electrolyte inlet distribution channel and an electrolyte outlet distribution channel, respectively, and the electrolyte inlet distribution channel and the electrolyte outlet distribution channel are respectively connected to the through hole in the middle of the rectangle.

[0010] Preferably, the electrolyte outlet through hole is located at the upper left of the electrode frame, the main electrolyte outlet channel is a rising wedge-shaped channel with a channel rise angle of 5 degrees to 15 degrees; the secondary electrolyte outlet channel is a serpentine channel arrangement with a channel turning angle of 180 degrees to 540 degrees.

[0011] Preferably, the electrolyte inlet through hole is located at the lower right of the electrode frame, the main electrolyte inlet channel is a rising wedge-shaped channel with a channel rise angle of 5 degrees to 15 degrees, and the secondary electrolyte inlet channel is a serpentine channel arrangement with a channel turning angle of 180 degrees to 540 degrees.

[0012] Preferably, both the electrolyte inlet distribution channel and the electrolyte outlet distribution channel are provided with electrolyte dispensing ports. The electrolyte dispensing ports connect the rectangular central through hole to the electrolyte inlet distribution channel and the electrolyte outlet distribution channel. The number of dispensing ports in the electrolyte inlet distribution channel and the electrolyte outlet distribution channel is set to 5-12, and the width of the dispensing ports is set to 3-8mm.

[0013] Preferably, the electrode frame material is made of PVC (polyvinyl chloride).

[0014] Preferably, the electrolyte inlet main channel and the electrolyte outlet main channel are respectively provided with flow-to-bottom and flow-to-rising-angle intervals.

[0015] The beneficial effects of the vanadium redox flow battery electrode frame structure described in this invention are as follows:

[0016] In this invention, the electrolyte inlet and outlet channels consist of three parts: a main channel, a secondary channel, and a distribution channel. The main channel is a rising wedge-shaped channel, with its cross-sectional area gradually decreasing as the electrolyte flows. While ensuring uniform flow distribution across each section of the stack, the electrolyte's flow resistance gradually increases within the electrode frame channels. The secondary electrolyte channels are arranged in a serpentine pattern, further extending the electrolyte flow path and increasing the flow resistance, thus reducing leakage current effects. The electrode frame structure provided by this invention increases the flow resistance of the electrolyte within the electrode frame channels without affecting the electrochemical reactions occurring within the porous electrode. Therefore, it effectively suppresses the influence of leakage current and improves battery performance.

[0017] In this invention, the electrode frame is made of PVC (polyvinyl chloride), which is easy to process. The main electrolyte inlet and outlet channels are distributed on the top and bottom sides of the electrode frame, while the secondary electrolyte inlet and outlet channels are distributed on the other two sides. The secondary electrolyte inlet and outlet channels are arranged in a serpentine pattern on the electrode frame, which greatly increases the flow path of the electrolyte and increases the internal flow resistance of the battery. In addition, the main electrolyte inlet and outlet channels are arranged in an ascending wedge shape from the electrolyte inlet and outlet to the secondary channels, which further increases the flow resistance of the electrolyte inside the electrode frame. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the traditional electrode frame structure in the comparative example proposed in this invention;

[0019] Figure 2 This is a schematic diagram of the electrode frame structure proposed in this invention;

[0020] Figure 3 This is a schematic diagram of the wedge-shaped flow channel for the electrolyte main channel proposed in this invention.

[0021] In the diagram: 1. Electrolyte outlet through-hole; 2. Electrolyte inlet through-hole; 3. Electrolyte outlet main channel; 4. Electrolyte inlet main channel; 5. Electrolyte outlet secondary channel; 6. Electrolyte inlet secondary channel; 7. Electrolyte outlet distribution channel; 8. Electrolyte inlet distribution channel; 9. Rectangular central through-hole; 10. Flowing to the rising angle interval; 11. Flowing to the bottom. Detailed Implementation

[0022] The technical solutions in this embodiment will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this embodiment, and not all embodiments.

[0023] Comparative Example

[0024] refer to Figure 1 The traditional electrode frame structure of an all-vanadium redox flow battery is as follows: Figure 1As shown, through holes are provided near the four corners of the electrode frame, serving as electrolyte inlet through holes 2 and electrolyte outlet through holes 1, respectively. A hollowed-out central through hole 7, capable of accommodating the porous electrode, is provided in the center of the rectangular plate. On one side surface of the electrode frame, near the upper and lower edges of the rectangular plate, electrolyte inlet main channel 4 and electrolyte outlet main channel 3 are respectively provided. Electrolyte inlet main channel 4 is connected to electrolyte inlet through hole 2, and electrolyte outlet main channel 3 is connected to electrolyte outlet through hole 1. Electrolyte outlet distribution channel 5 and electrolyte inlet distribution channel 6 are provided on the upper and lower edges near the central through hole of the rectangular plate. Electrolyte inlet distribution channel 6 is connected to electrolyte inlet main channel 4, and electrolyte outlet distribution channel 5 is connected to electrolyte outlet main channel 3. The electrolyte flows through the electrolyte inlet through hole, through electrolyte inlet main channel 3 to electrolyte inlet distribution channel 6, and then flows into the porous electrode area through the distribution port. After the electrolyte reacts in the porous electrode region, it flows through the electrolyte outlet distribution channel 5 and the electrolyte outlet main channel 3 to the electrolyte outlet through-hole, thus exiting the electrode frame. The cross-sectional width of both the electrolyte inlet and outlet channels is 8 mm. The frame material is PVC.

[0025] Figure 1 In the middle section, there are: 1. Electrolyte outlet through hole, 2. Electrolyte inlet through hole, 3. Electrolyte outlet main channel, 4. Electrolyte inlet main channel, 5. Electrolyte outlet distribution channel, 6. Electrolyte inlet distribution channel, and 7. Middle through hole.

[0026] Number of fuel cell stack sections: 10;

[0027] Current density: 80 mA / cm 2 Charging cut-off voltage: 15.5V, discharging cut-off voltage: 10V;

[0028] The charge / discharge coulombic efficiency of the fuel cell stack is 97.2%, the voltage efficiency is 85.3%, and the energy efficiency is 82.9%.

[0029] Example 1

[0030] refer to Figure 2-3 A vanadium redox flow battery electrode frame structure includes an electrode frame 12, which is a rectangular plate structure. Through holes are provided near the four corners of the electrode frame 12, serving as an electrolyte inlet through hole 2 and an electrolyte outlet through hole 1, respectively. A hollow rectangular central through hole 9, capable of accommodating a porous electrode, is provided in the center of the rectangular plate of the electrode frame 12. An electrolyte inlet main channel 3 and an electrolyte outlet main channel 4 are provided on one side surface of the electrode frame 12, located near the upper and lower edges of the electrode frame 12. The electrolyte inlet main channel 4 is connected to the electrolyte inlet through hole 2, and the electrolyte outlet main channel 3 is connected to the electrolyte outlet through hole 1.

[0031] In this embodiment, the surfaces of the other two sides of the electrode frame 12 are respectively provided with an electrolyte inlet secondary channel 6 and an electrolyte outlet secondary channel 5. The electrolyte inlet secondary channel 6 is connected to the electrolyte inlet main channel 4, and the electrolyte outlet secondary channel 5 is connected to the electrolyte outlet main channel 3.

[0032] In this embodiment, the upper and lower sides of the electrode frame 12 near the through hole 9 in the middle of the rectangle are respectively provided with an electrolyte inlet distribution channel 8 and an electrolyte outlet distribution channel 7, which are connected to the through hole 9 in the middle of the rectangle.

[0033] In this embodiment, the electrolyte outlet through hole 1 is located at the upper left of the electrode frame 12, the electrolyte outlet main channel 3 is a rising wedge-shaped channel with a channel rising angle of 10 degrees; the electrolyte outlet secondary channel 5 is a serpentine channel arrangement with a channel turning angle of 180 degrees.

[0034] In this embodiment, the electrolyte inlet through hole 2 is located at the lower right of the electrode frame 12, the electrolyte inlet main channel 4 is a rising wedge-shaped channel with a channel rising angle of 10 degrees, and the electrolyte inlet secondary channel 6 is a serpentine channel arrangement with a channel turning angle of 180 degrees.

[0035] In this embodiment, both the electrolyte inlet distribution channel 8 and the electrolyte outlet distribution channel 7 are provided with electrolyte dispensing ports. The electrolyte dispensing ports connect the rectangular central through hole 9 to the electrolyte inlet distribution channel 8 and the electrolyte outlet distribution channel 7. The number of dispensing ports in the electrolyte inlet distribution channel 8 and the electrolyte outlet distribution channel 7 is set to 8, and the width of the dispensing ports is set to 6mm.

[0036] In this embodiment, the electrode frame 12 is made of PVC (polyvinyl chloride).

[0037] In this embodiment, the electrolyte inlet main channel 3 and the electrolyte outlet main channel 4 are respectively provided with a flow to the bottom 11 and a flow to the rising angle interval 10.

[0038] Number of fuel cell stack sections: 10;

[0039] Current density: 80 mA / cm 2 Charging cut-off voltage: 15.5V, discharging cut-off voltage: 10V;

[0040] The charge / discharge coulombic efficiency of the fuel cell stack is 98.9%, the voltage efficiency is 88.2%, and the energy efficiency is 88.6%.

[0041] Example 2

[0042] refer to Figure 2-3A vanadium redox flow battery electrode frame structure includes an electrode frame 12, which is a rectangular plate structure. Through holes are provided near the four corners of the electrode frame 12, serving as an electrolyte inlet through hole 2 and an electrolyte outlet through hole 1, respectively. A hollow rectangular central through hole 9, capable of accommodating a porous electrode, is provided in the center of the rectangular plate of the electrode frame 12. An electrolyte inlet main channel 3 and an electrolyte outlet main channel 4 are provided on one side surface of the electrode frame 12, located near the upper and lower edges of the electrode frame 12. The electrolyte inlet main channel 4 is connected to the electrolyte inlet through hole 2, and the electrolyte outlet main channel 3 is connected to the electrolyte outlet through hole 1.

[0043] In this embodiment, the surfaces of the other two sides of the electrode frame 12 are respectively provided with an electrolyte inlet secondary channel 6 and an electrolyte outlet secondary channel 5. The electrolyte inlet secondary channel 6 is connected to the electrolyte inlet main channel 4, and the electrolyte outlet secondary channel 5 is connected to the electrolyte outlet main channel 3.

[0044] In this embodiment, the upper and lower sides of the electrode frame 12 near the through hole 9 in the middle of the rectangle are respectively provided with an electrolyte inlet distribution channel 8 and an electrolyte outlet distribution channel 7, which are connected to the through hole 9 in the middle of the rectangle.

[0045] In this embodiment, the electrolyte outlet through hole 1 is located at the upper left of the electrode frame 12, the electrolyte outlet main channel 3 is a rising wedge-shaped channel with a channel rising angle of 12 degrees; the electrolyte outlet secondary channel 5 is a serpentine channel arrangement with a channel turning angle of 540 degrees.

[0046] In this embodiment, the electrolyte inlet through hole 2 is located at the lower right of the electrode frame 12, the electrolyte inlet main channel 4 is a rising wedge-shaped channel with a channel rising angle of 12 degrees, and the electrolyte inlet secondary channel 6 is a serpentine channel arrangement with a channel turning angle of 540 degrees.

[0047] In this embodiment, both the electrolyte inlet distribution channel 8 and the electrolyte outlet distribution channel 7 are provided with electrolyte dispensing ports. The electrolyte dispensing ports connect the rectangular central through hole 9 to the electrolyte inlet distribution channel 8 and the electrolyte outlet distribution channel 7. The number of dispensing ports in the electrolyte inlet distribution channel 8 and the electrolyte outlet distribution channel 7 is set to 6, and the width of the dispensing ports is set to 4mm.

[0048] In this embodiment, the electrode frame 12 is made of PVC (polyvinyl chloride).

[0049] In this embodiment, the electrolyte inlet main channel 3 and the electrolyte outlet main channel 4 are respectively provided with a flow to the bottom 11 and a flow to the rising angle interval 10.

[0050] Number of fuel cell stack sections: 10;

[0051] Current density: 80 mA / cm 2 Charging cut-off voltage: 15.5V, discharging cut-off voltage: 10V;

[0052] The fuel cell stack has a charge / discharge coulombic efficiency of 99.3%, a voltage efficiency of 88.9%, and an energy efficiency of 88.3%.

[0053] Table 1: Battery Performance Comparison

[0054] fuel cell stack serial number Coulomb efficiency % Voltage efficiency % Energy efficiency % Comparative Example 97.2 85.3 82.9 Example 1 98.9 88.2 87.2 Example 2 99.3 88.9 88.3

[0055] In summary, the battery performance comparison shows that the electrode frame of this invention, due to the wedge-shaped flow channel of the main electrolyte channel, gradually reduces the cross-sectional area of ​​the electrolyte flow path. Furthermore, the addition of a secondary electrolyte flow channel ensures a normal electrolyte flow path and increases electrolyte flow resistance, effectively suppressing the influence of leakage current. Therefore, the coulombic efficiency of the battery stack is significantly improved compared to electrode frames using traditional structures. Compared to Example 1, the rise angle of the wedge-shaped flow channel in Example 2 is further increased, and the bending angle of the secondary electrolyte flow channel is further improved, thus further increasing electrolyte flow resistance and further enhancing the coulombic efficiency of the battery stack.

[0056] The above description is only a preferred embodiment of this practice, but the scope of protection of this embodiment is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the scope of the technology disclosed in this embodiment, based on the technical solution and inventive concept of this embodiment, should be covered within the scope of protection of this embodiment.

Claims

1. A vanadium redox flow battery electrode frame structure, comprising an electrode frame (12), characterized in that, The electrode frame (12) is a rectangular plate structure. There are through holes at the edges near the four corners of the electrode frame (12). The four through holes serve as electrolyte inlet through holes (2) and electrolyte outlet through holes (1), respectively. There is a hollow rectangular central through hole (9) in the middle of the rectangular plate of the electrode frame (12) that can accommodate the porous electrode. There are electrolyte inlet main channel (4) and electrolyte outlet main channel (3) on one side surface of the electrode frame (12). The electrolyte inlet main channel (4) and electrolyte outlet main channel (3) are close to the upper and lower sides of the electrode frame (12). The electrolyte inlet main channel (4) is connected to the electrolyte inlet through hole (2), and the electrolyte outlet main channel (3) is connected to the electrolyte outlet through hole (1). The other two sides of the electrode frame (12) are respectively provided with an electrolyte inlet secondary channel (6) and an electrolyte outlet secondary channel (5). The electrolyte inlet secondary channel (6) is connected to the electrolyte inlet main channel (4), and the electrolyte outlet secondary channel (5) is connected to the electrolyte outlet main channel (3). The electrolyte outlet through hole (1) is located at the upper left of the electrode frame (12). The main electrolyte outlet channel (3) is a rising wedge-shaped channel with a channel rising angle of 5 degrees to 15 degrees. The secondary electrolyte outlet channel (5) is a serpentine channel arrangement with a channel turning angle of 180 degrees to 540 degrees. The electrolyte inlet through hole (2) is located at the lower right of the electrode frame (12). The electrolyte inlet main channel (4) is a rising wedge-shaped channel with a channel rising angle of 5 degrees to 15 degrees. The electrolyte inlet secondary channel (6) is a serpentine channel arrangement with a channel turning angle of 180 degrees to 540 degrees. The electrolyte inlet main channel (4) and the electrolyte outlet main channel (3) are respectively provided with a flow to the bottom (11) and a flow to the rising angle interval (10).

2. The electrode frame structure of an all-vanadium redox flow battery according to claim 1, characterized in that, The electrode frame (12) has an electrolyte inlet distribution channel (8) and an electrolyte outlet distribution channel (7) on the upper and lower sides near the through hole (9) in the middle of the rectangle, respectively. The electrolyte inlet distribution channel (8) and the electrolyte outlet distribution channel (7) are connected to the through hole (9) in the middle of the rectangle.

3. The electrode frame structure of an all-vanadium redox flow battery according to claim 2, characterized in that, Both the electrolyte inlet distribution channel (8) and the electrolyte outlet distribution channel (7) are provided with electrolyte distribution ports, which connect the rectangular central through hole (9) to the electrolyte inlet distribution channel (8) and the electrolyte outlet distribution channel (7).

4. The electrode frame structure of an all-vanadium redox flow battery according to claim 2, characterized in that, The number of dispensing ports of the electrolyte inlet distribution channel (8) and the electrolyte outlet distribution channel (7) is set to 5-12, and the width of the dispensing ports is set to 3-8mm.

5. The electrode frame structure of an all-vanadium redox flow battery according to claim 1, characterized in that, The electrode frame (12) is made of PVC (polyvinyl chloride).

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