A liquid flow battery stack liquid guide plate structure and application

Abstract

The present invention relates to a liquid flow battery stack liquid guide plate structure, wherein strip-shaped limit blocks perpendicular to the surface of the plate are respectively arranged along the length direction at the edges of the four sides of the surface of one side of a liquid guide plate of the stack, and strip-shaped limit blocks corresponding to the above-mentioned liquid guide plate and / or staggered strip-shaped limit blocks are arranged on another liquid guide plate. A corresponding through hole is arranged on the corresponding limit block, and the through hole passes through the positioning block and the liquid guide plate. During the assembly and compression of the stack, the limit block can well limit the lateral displacement of the electrode frame, prevent the tension on the material caused by the extrusion and displacement of the electrode frame, better meet the needs of sealing and positioning, and improve the reliability and assembly success rate of the stack. In addition, the limit block limits the compression thickness of the stack to avoid material damage caused by overpressure.

Description

Technical Field

[0001] The invention relates to a liquid flow battery stack structure, and in particular to the structure of a liquid guide plate in a liquid flow battery stack. Background Art

[0002] With the rapid development of the economy and society, the demand for energy in all walks of life has increased dramatically, which has put forward higher requirements for the stability of the power grid. Real-time source-load balance, application of renewable energy and upgrading of energy structure are driving the national power grid to develop in a smarter, more complete and stronger direction. For these new requirements, new technologies are needed to improve the flexibility of the power grid and meet the needs of large-scale peak and frequency regulation. Energy storage technology has emerged as the times require, which can timely adjust the frequency and peak by real-time dispatching of electric energy in the power grid; and increase the grid connection time by re-rectifying renewable energy. Energy storage technology has developed rapidly in the past two decades, among which electrochemical energy storage technology has stood out due to its high efficiency, flexible design and suitability for large-scale energy storage. As one of the electrochemical energy storage technologies, liquid flow battery has been valued by scientists and companies around the world for its advantages such as independent design of power and capacity, high efficiency, strong flexibility, deep discharge and long life, and has made significant progress. Energy storage power stations using this technology have also been recognized by the market.

[0003] The flow battery stack is the most critical component in the flow battery system, which determines the performance and reliability of the system and is the key place to complete power conversion in the system. In the past, the focus on the flow battery stack was mainly on improving performance, with the emphasis on the development of materials and structures. In actual industrial production, the process procedures also determine the reliability and performance consistency of the stack. Especially in the process of assembling the stack, the dozens of tons of pressure applied by the hydraulic press will compress the stacked cells. The slight sliding of the electrodes, plates, and electrode frames in the battery will be gradually magnified during the compression process until they are completely compressed, and the maximum deviation will reach about 5mm. Such a large deviation will inevitably lead to the tearing of battery materials, seriously affecting the reliability of the stack. In addition, the deviation will cause the misalignment of the seal positioning, exacerbating the leakage of the electrolyte in the stack and the leakage of the electrolyte. Summary of the invention

[0004] In order to improve the reliability of battery stack assembly, reduce the lateral displacement of the electrode frame during the battery stack compression process, and limit the battery stack compression thickness, the present invention provides a liquid flow battery stack liquid guide plate structure.

[0005] The liquid flow battery stack liquid guide plate structure comprises two liquid guide plates with electrolyte inlet and outlet through holes, the liquid guide plates are rectangular flat plates, and the two flat plates are arranged parallel to each other;

[0006] Wherein, the liquid guide plate includes any one of the following two structures:

[0007] The first type: strip-shaped limit blocks perpendicular to the surface of the plate are respectively provided along the length direction of the side near the edges of the four sides of one side surface of one of the plates A; one or more positioning through holes a penetrating the limit block and the plate are opened in the direction of the plate on the surface of each limit block away from the plate, that is, the positioning through hole a is arranged in a direction perpendicular to the surface of the plate and penetrates the limit block and the plate A;

[0008] A positioning through hole b corresponding to the positioning through hole a on the plate A is provided on the other plate B; each stopper is a rectangle with equal height, that is, the distance from the surface of the stopper away from the plate to the surface of the plate where it is located is equal, which is the distance between the plate A and the plate B; the plate A and the plate B are arranged facing each other, and the corresponding four sides of the plate A and the plate B are separated by strip-shaped stoppers;

[0009] The second type: strip-shaped limit blocks perpendicular to the surface of the plate are respectively provided along the length direction of the side at the edge of 1-4 of the four sides on one side surface of one of the plates A; one or more positioning through holes a penetrating the limit block and the plate are opened in the direction of the plate on the surface of each limit block away from the plate, that is, the positioning through hole a is arranged in a direction perpendicular to the surface of the plate and penetrates the limit block and the plate A;

[0010] On the edge of one side of the surface of the other plate B facing the plate A and close to 1-4 of the four sides, strip-shaped limit blocks are respectively provided along the length direction thereof and are perpendicular to the plate surface and correspond to and / or intersect with the upper limit blocks of the plate A;

[0011] When the corresponding strip-shaped limit blocks are provided, a positioning through hole b is provided on the surface of each limit block away from the flat plate B, which passes through the limit block and the flat plate B and corresponds to the positioning through hole a. That is, the positioning through hole b is provided in a direction perpendicular to the surface of the flat plate B and passes through the limit block and the flat plate B.

[0012] When the staggered strip-shaped limit blocks are used, a positioning through hole b corresponding to the positioning through hole a on the plate A is opened on each limit block away from the plate B;

[0013] The flat plate A and the flat plate B are arranged facing each other, and the four corresponding sides of the flat plate A and the flat plate B are separated by strip-shaped limit blocks;

[0014] The above-mentioned limit blocks are all rectangular. Two corresponding limit blocks or one staggered limit block on the plate A and the plate B are respectively used as a group of limit blocks. The heights of the limit block groups are equal, that is, the sum of the heights of any group of limit blocks in the direction perpendicular to the surface of the plate is equal to the sum of the heights of the other groups, which are the distances between the plate A and the plate B.

[0015] In the above-mentioned liquid guide plate structure, the number of strip-shaped limiting blocks arranged on any one of the four sides of the opposite surfaces of the flat plate A or the flat plate B is 1-10, preferably 1-6.

[0016] In the above-mentioned liquid guide plate structure, flat plate A and flat plate B are arranged opposite to each other, and there are strip-shaped limit blocks between the corresponding four sides of flat plate A and flat plate B; and the length of the strip-shaped limit block on each side along the side length direction is 1 / 10-9 / 10 of the length of the side strip, preferably 1 / 4-3 / 4.

[0017] The above-mentioned liquid guide plate structure is applied to the battery stack. When the liquid flow battery stack is assembled, the battery assembly including the electrode frame is placed in the middle between the two flat plates, within the area surrounded by the strip limit block, and the distance between the limit block and the electrode frame measured inside it is 0.1-2mm, preferably 0.2-1mm; then the positioning rod is inserted into the corresponding positioning through hole a and positioning through hole b of the two flat plates to position the battery assembly.

[0018] The battery components in the flow battery stack using the liquid guide plate of the present invention include a negative bipolar plate, a negative electrode frame, a negative electrode, an ion conductive membrane, a positive electrode, a positive electrode frame, a positive bipolar plate, and sealing materials between the adjacent components.

[0019] The present invention has the following advantages:

[0020] The present invention provides the following advantages by setting a limit block on the liquid flow battery guide plate:

[0021] 1. It limits the lateral displacement of materials such as electrode frames and bipolar plates in the battery stack, reduces or avoids the lateral tension on the materials, and improves the reliability of the battery stack;

[0022] 2. Limit the compression thickness of the battery stack to avoid material damage caused by overpressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A liquid guide plate A1 structure of a flow battery stack proposed by the present invention, used in Example 1;

[0024] Among them: 1. positive electrode electrolyte inlet; 2. negative electrode electrolyte inlet; 3. negative electrode electrolyte distribution port flowing into the electrode frame; 4. positive electrode electrolyte distribution port flowing into the electrode frame; 5. limit block set on the long side of the liquid guide plate A1; 6. limit block set on the short side of the liquid guide plate A1;

[0025] Figure 2 A method proposed by the present invention and Figure 1 The liquid guide plate B1 structure used in conjunction with the liquid guide plate of the flow battery stack;

[0026] Among them, 7. positive electrode electrolyte outlet; 8. negative electrode electrolyte outlet; 9. negative electrode electrolyte distribution port flowing out of the electrode frame; 10. positive electrode electrolyte distribution port flowing out of the electrode frame; 11. limit block set on the long side of the liquid guide plate B1; 12. limit block set on the short side of the liquid guide plate B1;

[0027] Figure 3 For adopting the present invention Figure 1 and Figure 2 The battery stack assembled with the liquid guide plate is used in Example 1;

[0028] Figure 4 Another liquid guide plate A2 structure of a flow battery stack proposed by the present invention is used in Example 2;

[0029] Wherein 13. a limit block is provided on the long side of the liquid guide plate A2; 14. a limit block is provided on the short side of the liquid guide plate A2;

[0030] Figure 5 A method proposed by the present invention and Figure 4 The liquid guide plate B2 structure used in conjunction with the liquid guide plate of the flow battery stack;

[0031] Wherein 15. a limit block disposed on the long side of the liquid guide plate B2 and offset from 13; 16. a limit block disposed on the short side of the liquid guide plate B2;

[0032] Figure 6 For adopting the present invention Figure 4 and Figure 5 The battery stack assembled with liquid guide plates is used in Example 2. DETAILED DESCRIPTION

[0033] Embodiment 1:

[0034] A flow battery stack structure, which consists of aluminum or steel metal end plates on both sides of the stack, Figure 1 and Figure 2 The supporting PVC liquid guide plates A1 and B1, copper current collecting plates and several single cells are connected in series. The positive electrolyte flows into the battery stack through the positive electrolyte inlet 1, and then flows into the positive electrolyte inlet on the electrode frame through the positive electrolyte distribution port 4 flowing into the electrode frame, flows through the electrodes of each single cell, and then flows into the liquid guide plate through the positive electrolyte distribution port 10 flowing out of the electrode frame, and then flows out of the battery stack through the positive electrolyte outlet 7; the negative electrolyte flows into the battery stack through the negative electrolyte inlet 2, and then flows into the negative electrolyte inlet on the electrode frame through the negative electrolyte distribution port 3 flowing into the electrode frame, flows through the negative electrode, and then flows into the liquid guide plate through the negative electrolyte distribution port 9 flowing out of the electrode frame, and then flows out of the battery stack through the negative electrolyte outlet 8.

[0035] Among them, 5 is a limit block set on the long side of the liquid guide plate A1 in the battery stack, and the design spacing between the limit block and the inner edge of the electrode frame is 0.4mm; 6 is a limit block set on the short side of the liquid guide plate A1 in the battery stack, and the design spacing between the limit block and the inner edge of the electrode frame is 0.4mm. 11 is a limit block set on the long side of the liquid guide plate B1 in the battery stack, and the design spacing between the limit block and the inner edge of the electrode frame is 0.4mm; 12 is a limit block set on the short side of the liquid guide plate B1 in the battery stack, and the design spacing between the limit block and the inner edge of the electrode frame is 0.4mm. When assembling the battery stack, the limit block 5 set on the long side of the liquid guide plate A1 and the limit block 11 set on the long side of the liquid guide plate B1; the limit block 6 set on the short side of the liquid guide plate A1 and the limit block 12 set on the short side of the liquid guide plate B1 are arranged opposite to each other. The limit block and the liquid guide plate are integrally structured. To ensure the strength and low deformation of the limit block, three metal screw through holes are set on the long side limit block of the limit block 5 set on the long side of the liquid guide plate A1, and three metal screw through holes are set on the corresponding limit block 11 set on the long side of the liquid guide plate B1. The metal screw through holes on the limit block 5 set on the long side of the liquid guide plate A1 and the limit block 11 set on the long side of the liquid guide plate B1 are assembled in a concentric manner. The metal screws position and connect the metal end plates and the liquid guide plates on both sides of the battery stack, and are compressed by the mold spring. Four corresponding positioning holes are respectively provided on the limit blocks 5 provided on the long side of the liquid guide plate A1 and the limit blocks 11 provided on the long side of the liquid guide plate B1. The corresponding positioning holes are installed concentrically during assembly and are positioned and installed together with the metal end plate through a white steel positioning rod with a diameter of 6-10 mm, which plays an auxiliary positioning effect. Similarly, one metal screw through hole is provided on each of the limit blocks 6 provided on the short side of the liquid guide plate A1, and a corresponding metal screw through hole is provided on the limit block 12 provided on the corresponding short side of the liquid guide plate B1. The metal screw through holes on the limit blocks 6 provided on the short side of the liquid guide plate A1 and the limit blocks 12 provided on the short side of the liquid guide plate B1 are assembled concentrically for positioning and pressing with the metal end plate.

[0036] The length of the limit block 5 set on the long side of the liquid guide plate A1 and the limit block 11 set on the long side of the liquid guide plate B1 set on A1 and B1 along the side length direction is 1 / 2 of the length of the long side of A1; the length of the limit block 6 set on the short side of the liquid guide plate A1 and the limit block 12 set on the short side of the liquid guide plate B1 set on A1 and B1 along the side length direction is 1 / 3 of the length of the short side of A1.

[0037] use Figure 1 and Figure 2 The liquid guide plate is used to assemble the battery stack. Figure 3As shown. The battery stack consists of 20 single cells, and the designed compression thickness is 200mm. The heights of the limit blocks 5 set on the long side of the liquid guide plate A1 and the limit blocks 11 set on the long side of the liquid guide plate B1 are both 100mm; the heights of the limit blocks 6 set on the short side of the liquid guide plate A1 and the limit blocks 12 set on the short side of the liquid guide plate B1 are both 100mm. The limit blocks 5 set on the long side of the liquid guide plate A1, the limit blocks 6 set on the short side of the liquid guide plate A1, the limit blocks 11 set on the long side of the liquid guide plate B1, and the limit blocks 12 set on the short side of the liquid guide plate B1 are chamfered with 3mm*3mm on the edges adjacent to the inner electrode frame to avoid getting stuck with the electrode frame during the compression of the battery stack.

[0038] The thickness of the battery stack assembled by the liquid guide plate structure is limited to the designed height of 200mm after compression; the misalignment between adjacent electrode frames is less than 0.4mm, and the maximum misalignment of the electrode frames in the entire battery stack is less than 0.8mm. After pressure testing for internal and external leakage, no leakage was found under 0.4bar for internal leakage and 2.5bar for external leakage.

[0039] By adopting the liquid guide plate structure proposed in the present invention to assemble the battery stack, the lateral displacement of the electrode frame during the assembly and compaction of the battery stack is well limited, the tension on the material caused by the extrusion and displacement of the electrode frame is prevented, the need for sealing and positioning is better met, and the reliability of the battery stack is improved. The compaction thickness of the battery stack is strictly controlled to avoid material damage caused by overpressure.

[0040] Embodiment 2:

[0041] A flow battery stack structure, which consists of aluminum or steel metal end plates on both sides of the stack, Figure 4 and Figure 5 The supporting PVC liquid guide plates A2 and B2, copper current collecting plates and several single cells are connected in series. The positive electrolyte flows into the battery stack through the positive electrolyte inlet 1, and then flows into the positive electrolyte inlet on the electrode frame through the positive electrolyte distribution port 4 flowing into the electrode frame, flows through the electrodes of each single cell, and then flows into the liquid guide plate through the positive electrolyte distribution port 10 flowing out of the electrode frame, and then flows out of the battery stack through the positive electrolyte outlet 7; the negative electrolyte flows into the battery stack through the negative electrolyte inlet 2, and then flows into the negative electrolyte inlet on the electrode frame through the negative electrolyte distribution port 3 flowing into the electrode frame, flows through the negative electrode, and then flows into the liquid guide plate through the negative electrolyte distribution port 9 flowing out of the electrode frame, and then flows out of the battery stack through the negative electrolyte outlet 8.

[0042] Among them, 13 is a limit block set on the long side of the liquid guide plate A2 in the battery stack. The limit blocks on the long sides of both sides are diagonally staggered, and the design spacing between the limit block and the edge of the electrode frame inside it is 0.4mm; 14 is a limit block set on the short side of the liquid guide plate A2 in the battery stack, and the design spacing between the limit block and the edge of the electrode frame inside it is 0.4mm. 15 is a limit block set on the long side of the liquid guide plate B1 in the battery stack, which is staggered with the limit block 13 set on the long side of the liquid guide plate A2, and the design spacing between the limit block and the edge of the electrode frame inside it is 0.4mm; 16 is a limit block set on the short side of the liquid guide plate B2 in the battery stack, and the design spacing between the limit block and the edge of the electrode frame inside it is 0.4mm.

[0043] When the battery stack is assembled, the limit blocks 13 and 15 set on the long side of the liquid guiding plate A2 and the limit blocks 13 set on the long side of the liquid guiding plate B2 that are staggered with the limit blocks 13 set on the long side of the liquid guiding plate A2 are placed relative to each other; the limit blocks 14 set on the short side of the liquid guiding plate A2 and 16 set on the short side of the liquid guiding plate B2 are placed relative to each other, and after assembly, the limit blocks 13 set on the long side of the liquid guiding plate A2 and 15 set on the long side of the liquid guiding plate B2 are staggered with the limit blocks 13 set on the long side of the liquid guiding plate A2; the limit blocks 14 set on the short side of the liquid guiding plate A2 and 16 set on the short side of the liquid guiding plate B2 are arranged relative to each other.

[0044] The limit block and the liquid guide plate are of an integrated structure. To ensure the strength and low deformation of the limit block, one metal screw through hole is provided on each of the limit blocks arranged on the long side of the liquid guide plate A2 (13). Similarly, one metal screw through hole is provided on each of the limit blocks arranged on the long side of the liquid guide plate B2 (15) and offset from the limit blocks arranged on the long side of the liquid guide plate A2 (13).

[0045] At the same time, a metal screw through hole corresponding to the metal screw through hole on the limit block set on the long side of 15. liquid guide plate B2 and the metal screw through hole corresponding to the metal screw through hole on the limit block set on the long side of 13. liquid guide plate A2 is set on the liquid guide plate B2, and the corresponding through holes are assembled in the center during installation. The metal screws position and connect the metal end plates on both sides of the battery stack and the liquid guide plates together, and are compressed by the mold spring.

[0046] Two positioning holes are respectively set on the limit block 13. Set on the long side of the liquid guiding plate A2 and the limit block 15. Set on the long side of the liquid guiding plate B2 and staggered with the limit block 13. Set positioning holes on the liquid guiding plates A2 and B2 at positions corresponding to the above positioning holes, and are positioned and installed together with the liquid guiding plates and the metal end plates through a white steel positioning stick with a diameter of 6-10mm, so as to achieve the effect of auxiliary positioning. Similarly, one metal screw through hole is set on each of the limit blocks 14. Set on the short side of the liquid guiding plate A2, and set corresponding metal screw through holes on the corresponding limit blocks 16. Set the through holes on the limit blocks 14. Set on the short side of the liquid guiding plate A2 and the limit blocks 16. Set on the short side of the liquid guiding plate B2 are assembled in an aligned manner for positioning with the metal end plates.

[0047] The length of 13. the limit block set on the long side of liquid guiding plate A2 and 15. the limit block set on the long side of liquid guiding plate B2 which is staggered with 13. the limit block set on the long side of liquid guiding plate A2 set on A2 and B2 along the side length direction is 1 / 5 of the length of the long side of A1; the length of 14. the limit block set on the short side of liquid guiding plate A2 and 16. the limit block set on the short side of liquid guiding plate B2 set on A2 and B2 along the side length direction is 1 / 3 of the length of the short side of A1.

[0048] use Figure 4 and Figure 5 The liquid guide plate is used to assemble the battery stack. Figure 6 As shown. The battery stack consists of 20 single cells, and the designed compression thickness is 200mm. Among them, the height of the limit block set on the long side of 13. Liquid guide plate A2 and the limit block set on the long side of 15. Liquid guide plate B2, which is offset from the limit block set on the long side of 13. Liquid guide plate A2, are both 200mm; the height of the limit block set on the short side of 14. Liquid guide plate A2 and the limit block set on the short side of 16. Liquid guide plate B2 are both 100mm. The limit blocks set on the long side of 13. Liquid guide plate A2 and the limit blocks set on the long side of 15. Liquid guide plate B2, which are offset from the limit blocks set on the long side of 13. Liquid guide plate A2, the limit blocks set on the short side of 14. Liquid guide plate A2 and the limit blocks set on the short side of 16. Liquid guide plate B2 are chamfered with 3mm*3mm on the edges adjacent to the inner electrode frame to avoid getting stuck with the electrode frame during the compression of the battery stack.

[0049] The thickness of the battery stack assembled by the liquid guide plate structure is limited to the designed height of 200mm after compression; the misalignment between adjacent electrode frames is less than 0.4mm, and the maximum misalignment of the electrode frames in the entire battery stack is less than 0.8mm. After pressure testing for internal and external leakage, no leakage was found under 0.4bar for internal leakage and 2.5bar for external leakage.

[0050] By adopting the liquid guide plate structure proposed in the present invention to assemble the battery stack, the lateral displacement of the electrode frame during the assembly and compaction of the battery stack is well limited, the tension on the material caused by the extrusion and displacement of the electrode frame is prevented, the need for sealing and positioning is better met, and the reliability of the battery stack is improved. The compaction thickness of the battery stack is strictly controlled to avoid material damage caused by overpressure.

Claims

1. A liquid flow battery stack liquid guide plate structure, comprising two liquid guide plates with electrolyte inlet and outlet through holes, characterized in that: The liquid guide plates are two rectangular flat plates with the same length and width, and the two flat plates are arranged parallel to each other; Includes any of the following two structures: The first type: strip-shaped limit blocks perpendicular to the surface of the plate are respectively provided along the length direction of the side near the edges of the four sides of one side surface of one of the plates A; one or more positioning through holes a penetrating the limit block and the plate are opened in the direction of the plate on the surface of each limit block away from the plate, that is, the positioning through hole a is arranged in a direction perpendicular to the surface of the plate and penetrates the limit block and the plate A; A positioning through hole b corresponding to the positioning through hole a on the plate A is provided on the other plate B; each stopper is a rectangle with equal height, that is, the distance from the surface of the stopper away from the plate to the surface of the plate where it is located is equal, which is the distance between the plate A and the plate B; the plate A and the plate B are arranged facing each other, and the corresponding four sides of the plate A and the plate B are separated by strip-shaped stoppers; The second type: strip-shaped limit blocks perpendicular to the surface of the plate are respectively provided along the length direction of the side at the edge of 1-4 of the four sides on one side surface of one of the plates A; one or more positioning through holes a penetrating the limit block and the plate are opened in the direction of the plate on the surface of each limit block away from the plate, that is, the positioning through hole a is arranged in a direction perpendicular to the surface of the plate and penetrates the limit block and the plate A; On the edge of one side of the surface of the other plate B facing the plate A and close to 1-4 of the four sides, strip-shaped limit blocks are respectively provided along the length direction thereof and are perpendicular to the plate surface and correspond to and / or intersect with the upper limit blocks of the plate A; When the corresponding strip-shaped limit blocks are provided, a positioning through hole b is provided on the surface of each limit block away from the flat plate B, which passes through the limit block and the flat plate B and corresponds to the positioning through hole a. That is, the positioning through hole b is provided in a direction perpendicular to the surface of the flat plate B and passes through the limit block and the flat plate B. When the staggered strip-shaped limit blocks are used, a positioning through hole b corresponding to the positioning through hole a on the plate A is opened on each limit block away from the plate B; The flat plate A and the flat plate B are arranged facing each other, and the four corresponding sides of the flat plate A and the flat plate B are separated by strip-shaped limit blocks; The limit blocks are all rectangular, and two corresponding limit blocks or one staggered limit block on the flat plate A and the flat plate B are respectively used as a group of limit blocks, and the heights between the limit block groups are equal, that is, the sum of the heights of any group of limit blocks in the direction perpendicular to the surface of the flat plate is equal to the sum of the heights of the other groups, which are the distances between the flat plate A and the flat plate B.

2. The structure according to claim 1, characterized in that: The number of strip-shaped limiting blocks arranged near any one of the four sides between the opposing surfaces of the flat plate A and the flat plate B is 1-10.

3. The structure according to claim 1, characterized in that: The number of strip-shaped limiting blocks arranged near any one of the four sides between the opposing surfaces of the flat plate A and the flat plate B is 1-6.

4. The structure according to claim 1, characterized in that: The plate A and the plate B are arranged facing each other, and strip-shaped limit blocks are provided between the four corresponding sides of the plate A and the plate B; and the length of the strip-shaped limit block on each side along the side length direction is 1 / 10-9 / 10 of the length of the side strip.

5. The structure according to claim 4, characterized in that: The length of the strip-shaped limiting block on each side along the side length direction is 1 / 4-3 / 4 of the length of the side strip.

6. Application of the structure according to any one of claims 1 to 5 in a liquid flow battery stack.

7. The use according to claim 6, characterized in that: When assembling the flow battery stack, the battery assembly including the electrode frame is placed in the middle between the two liquid guide plates, within the area surrounded by the strip-shaped limit block, and the distance between the limit block and the electrode frame inside it is 0.1-2mm; Then, the positioning rods are inserted into the corresponding positioning through holes a and positioning through holes b of the two flat plates to position the battery assembly.

8. The use according to claim 7, characterized in that: The battery assembly including the electrode frame includes a negative bipolar plate, a negative electrode frame, a negative electrode, an ion conductive membrane, a positive electrode, a positive electrode frame, and a positive bipolar plate stacked in sequence.

9. The use according to claim 7, characterized in that: The distance between the limiting block and the electrode frame inside it is 0.2-1 mm.

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