Electrolyte storage tank flow guide device applied to liquid flow energy storage system

Abstract

The utility model relates to the field of flow batteries, in particular to an electrolyte storage tank flow guide device applied to a flow energy storage system, which comprises an upper-layer flow guide plate, a middle-layer flow guide plate and a bottom-layer flow guide plate, the middle-layer flow guide plate comprises a horizontal plate and a vertical plate connected to one side of the horizontal plate, and the uppermost end of the vertical plate exceeds an overflow liquid level. Certain spaces are reserved between the upper-layer flow guide plate and the vertical plate of the middle-layer flow guide plate and between the middle-layer flow guide plate and the inner wall of the electrolyte storage device, so that an overflow electrolyte buffer space is formed; a liquid distribution guide plate is arranged on one side of the bottom guide plate, and a flow control mechanism is arranged between the bottom guide plate and the liquid distribution guide plate; the liquid distribution guide plate is provided with a hole for the liquid suction pipe to pass through, and the liquid distribution pipe is located below the liquid distribution guide plate. According to the utility model, the problem that the overflow electrolyte is mixed with the original electrolyte can be solved, and the electrolyte extracted to the galvanic pile module for reaction is ensured to be unmixed electrolyte, so that the normal charge-discharge reaction is ensured.

Description

Technical Field

[0001] This utility model relates to the field of flow batteries, specifically an electrolyte storage tank guiding device applied to a flow energy storage system. Background Technology

[0002] Vanadium redox flow batteries, as a novel energy storage system, offer advantages such as high energy conversion efficiency, flexible site selection, safety, and environmental friendliness. They can address the instability, discontinuity, and uncontrollability of renewable energy generation, contributing to peak shaving and valley filling in the power system and regulating energy supply and demand imbalances. Therefore, they are widely used in large-capacity energy storage for renewable energy sources like wind and solar power. The main operating principle of vanadium redox flow batteries is as follows: electrolytes containing vanadium ions of different valence states are placed in separate tanks. An external pump draws electrolyte from the distribution pipe at the bottom of the tank, supplying different valence states of electrolyte to the stack module. Vanadium ions of different valence states in the electrolyte undergo electron transfer through the ion-conducting membrane, resulting in a charge-discharge reaction. The reaction during charging is as follows: Positive electrode: VO 2+ +H2O→VO2 + +2H + +e - Negative electrode: V 3+ +e - →V 2+ The reaction during discharge is as follows: Positive electrode: VO2 + +2H + +e - →VO 2+ +H2O; Negative electrode: V 2+ →V 3+ +e - .

[0003] Under actual operating conditions, due to the significant difference in viscosity and osmotic pressure of the electrolyte in the storage tanks, some electrolyte will pass through the proton exchange membrane into the electrolyte circulation of another storage tank, causing changes in electrolyte concentration and volume, and leading to capacity decay in the flow battery. To maintain stable discharge capacity, it is necessary to actively replenish the electrolyte in the storage tanks. Therefore, overflow holes are opened on adjacent positive and negative electrode storage tanks and connected by pipes. The electrolyte overflow is automated by utilizing the height difference between the electrolyte levels in the positive and negative electrode storage tanks, achieving the purpose of replenishing electrolyte. Since the vanadium ion valence states in the electrolytes of the positive and negative electrode storage tanks differ significantly, without a flow guiding structure, the positive electrode overflow electrolyte containing high concentrations of tetravalent and pentavalent vanadium ions will directly mix with the original divalent and trivalent electrolyte in the negative electrode storage tank. The mixed electrolyte is then drawn into the stack module by the distribution pipe in the negative electrode storage tank, affecting the ongoing charge and discharge reactions, reducing the reaction rate, and increasing battery operating time. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide an electrolyte storage tank guiding device for a flow energy storage system, which controls the distribution of overflowing positive electrolyte so that the overflowing positive electrolyte is distributed in the middle and upper layers of the original electrolyte, thereby ensuring the purity of the negative electrolyte input to the fuel cell stack module.

[0005] To solve the aforementioned technical problem, the present invention adopts the following technical solution: an electrolyte storage tank guiding device for a liquid flow energy storage system, comprising an upper guiding plate, a middle guiding plate, and a bottom guiding plate arranged in layers within the electrolyte storage tank. The middle guiding plate includes a horizontal plate and a vertical plate connected to one side of the horizontal plate. The uppermost end of the vertical plate extends beyond the overflow liquid surface. A certain space is left between the vertical plates of the upper and middle guiding plates, and between the middle guiding plate and the inner wall of the electrolyte storage device, so that an overflow electrolyte buffer space is formed between the upper, middle, and bottom guiding plates. A liquid distribution guiding plate is provided on one side of the bottom guiding plate, and a flow control mechanism that closes or opens according to the overflow electrolyte pressure is provided between the bottom guiding plate and the liquid distribution guiding plate. A hole is opened on the liquid distribution guiding plate to allow a liquid suction pipe to pass through, and the liquid distribution pipe is located below the liquid distribution guiding plate.

[0006] Furthermore, the flow control mechanism includes a baffle, a rotating shaft, and a spring. The bottom of the baffle is rotatably connected to the bottom guide plate via the rotating shaft. The top of the baffle is closed at the bottom of the middle guide plate or opened and pressed against the liquid distribution guide plate. The spring is located between the bottom of the baffle and the bottom guide plate. In the initial state and when the overflow electrolyte pressure is less than the set value, the baffle is in the closed state, the overflow electrolyte buffer space is not connected to the space in the electrolyte storage state, and the overflow electrolyte does not mix with the original liquid in the electrolyte storage state. When the overflow electrolyte pressure is greater than the set value, the baffle opens, the overflow electrolyte buffer space is connected to the space in the electrolyte storage state, and the overflow electrolyte mixes with the electrolyte in the negative electrode tank through the liquid distribution guide plate, and remains in the upper layer of the original electrolyte in the tank for a long time.

[0007] Furthermore, the side of the electrolyte storage device with the overflow hole is called the overflow side, and the two sides connected to the overflow side are called the front side and the rear side. The upper guide plate and the lower guide plate are connected to the inner wall of the overflow side, the inner wall of the front side, and the inner wall of the rear side, and the middle guide plate is connected to the inner wall of the front side and the inner wall of the rear side.

[0008] Furthermore, the upper, middle, and lower air deflectors are plate-like structures with flat surfaces on both the top and bottom.

[0009] Furthermore, the end of the liquid distribution guide plate facing the flow control mechanism is an inclined plate.

[0010] Furthermore, this device is installed in the negative electrode storage tank.

[0011] Furthermore, the electrolyte storage tank is a square or cylindrical tank.

[0012] The beneficial effects of this invention are as follows: This flow-guiding structure ensures that the overflowing vanadium ion electrolyte in the electrolyte storage tank is uniformly and stably maintained in the upper layer near the overflow position of the electrolyte in another storage tank, without affecting the extraction of high-concentration divalent and trivalent vanadium ion electrolyte by the distribution pipe in the negative electrode storage tank. This flow-guiding structure is simple, has minimal impact on the stored electrolyte volume, and does not affect the normal operation of the flow battery's charging and discharging. Simultaneously, it ensures that the concentration of divalent and trivalent vanadium ions in the electrolyte extracted from the storage tank and delivered to the stack module remains stable, which is beneficial for the normal progress of the charging and discharging reaction. By setting a flow control mechanism, the flow of the overflowing electrolyte can be further controlled, allowing the positive electrode overflowing electrolyte to be maintained within a localized area of ​​the negative electrode storage tank at a relatively small volume. This achieves isolation between the overflowing electrolyte and the original electrolyte, without affecting the composition and concentration of the original electrolyte in the negative electrode storage tank. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of this utility model;

[0014] In the diagram: I. Positive electrode tank, II. Negative electrode tank, III. Flow control structure, 1. Suction pipe, 2. Distribution pipe, 3. Overflow pipe, 4. Upper guide plate, 5. Middle guide plate, 6. Bottom guide plate, 7. Baffle, 8. Spring, 9. Distribution guide plate, 10. Rotating shaft. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0016] Example 1

[0017] This embodiment discloses a flow guiding device for an electrolyte storage tank used in a flow energy storage system, such as... Figure 1 As shown, the electrolyte storage tank includes a positive electrode storage tank I and a negative electrode storage tank II. Both tanks are square or cylindrical, with overflow holes at their top. These overflow holes are connected by an overflow pipe 3. The electrolyte overflow is automated by utilizing the height difference between the electrolyte levels in the positive electrode storage tank I and the negative electrode storage tank II, thus replenishing the electrolyte. A suction pipe 1 and a distribution pipe 2 are provided between the positive electrode storage tank I and the negative electrode storage tank II and the fuel cell stack module. The distribution pipe 2 is located below the bottom guide plate and has small holes on its surface. These holes are used to extract the existing electrolyte from the storage tanks and then send it to the fuel cell stack module through the suction pipe 1 for charging and discharging reactions.

[0018] The flow guiding device includes an upper flow guiding plate 4, a middle flow guiding plate 5, and a bottom flow guiding plate 6 arranged in layers within the negative electrode storage tank II. The side of the negative electrode storage tank II with the overflow hole is called the overflow side, and the two sides connected to the overflow side are called the front side and the rear side. The upper flow guiding plate 4 and the bottom flow guiding plate 6 are connected to the inner walls of the overflow side, the front side, and the rear side, respectively, while the middle flow guiding plate 5 is connected to the inner walls of the front side and the rear side. That is, the upper flow guiding plate 4, the middle flow guiding plate 5, the bottom flow guiding plate 6, and the liquid distribution flow guiding plate 9 are completely horizontally connected to the inner wall of the storage tank. The electrolyte overflowing through the overflow hole is blocked by the upper flow guiding plate 4 and will laterally diffuse and mix in the original electrolyte in the storage tank. As the amount of overflowing electrolyte increases, its diffusion will be blocked again by the middle flow guiding plate 5 and the bottom flow guiding plate 6.

[0019] The middle layer guide plate 5 includes a horizontal plate and a vertical plate connected to one side of the horizontal plate. The uppermost end of the vertical plate extends beyond the overflow liquid surface to prevent the overflow electrolyte from mixing with the original electrolyte. A certain space is left between the vertical plates of the upper layer guide plate 4 and the middle layer guide plate 5, and between the middle layer guide plate 5 and the inner wall of the electrolyte storage device, forming an overflow electrolyte buffer space between the upper layer guide plate, the middle layer guide plate, and the bottom layer guide plate. In this embodiment, the upper layer guide plate 4, the middle layer guide plate 5, and the bottom layer guide plate 6 are plate-like structures with flat upper and lower surfaces. The middle layer guide plate 5 uses a right-angle structure to block the flow of electrolyte.

[0020] A liquid distribution guide plate 9 is provided on one side of the bottom guide plate 6. A flow control mechanism III, which closes or opens according to the overflow electrolyte pressure, is provided between the bottom guide plate 6 and the liquid distribution guide plate 9. The liquid distribution guide plate 9 has a hole for the liquid suction pipe 1 to pass through, and the liquid distribution pipe 2 is located below the liquid distribution guide plate 9. The flow control mechanism includes a baffle 7, a rotating shaft 10, and a spring 8. The bottom of the baffle 7 is rotatably connected to the bottom guide plate 6 via the rotating shaft 10. The top of the baffle 7 is closed at the bottom of the middle guide plate 5 (solid line position in the figure) or opened and pressed against the liquid distribution guide plate 9 (dashed line position in the figure). The spring 8 is located between the bottom of the baffle 7 and the bottom guide plate 6. The end of the liquid distribution guide plate 9 facing the flow control mechanism III is an inclined plate, which further plays a blocking role. As the overflow electrolyte increases, it will be blocked by the flow control structure III. When the pressure generated by the overflow electrolyte exceeds the elastic force of the spring 8, the overflow electrolyte will pass through the baffle 7.

[0021] The working principle of this utility model is as follows: When there is no overflow electrolyte, the liquid distribution pipe 2 can normally draw electrolyte from the bottom of the storage tank and send it to the fuel cell stack module; when the flow rate of the positive electrode overflow electrolyte entering the negative electrode storage tank through the overflow pipe is small, since the liquid pressure of the overflow electrolyte fails to exceed the elastic force of the traction spring 8 in the flow control structure Ⅲ, the baffle 7 in the flow control structure Ⅲ will be in the solid line position, maintaining its original closed state, and the electrolyte on the right side will not be affected.

[0022] When the positive electrode overflow electrolyte flow rate is large or a large amount of overflow electrolyte accumulates on the left side of the negative electrode tank, as the liquid level rises continuously, the liquid pressure generated by the electrolyte on the left side continues to rise until it exceeds the elastic force of the traction spring 8. The baffle 7 will rotate to the position indicated by the dotted line and press against the liquid distribution guide plate 9. At this time, the flow control structure Ⅲ is in the open state, and the overflow electrolyte mixes with the electrolyte in the negative electrode tank through the liquid distribution guide plate 9. Due to the blocking effect of the liquid distribution guide plate 9, the overflow electrolyte remains in the upper layer of the original electrolyte in the tank for a long time, thereby maintaining the stability of the electrolyte composition extracted from the negative electrode tank.

[0023] When the liquid levels on the left and right sides of the flow control structure Ⅲ in the negative electrode storage tank reach equilibrium, the flow control structure Ⅲ will rely on the elastic force of the spring 8 to restore the baffle 7 to its original position.

[0024] This invention effectively solves the problem of overflow electrolyte mixing with the original electrolyte by adding a flow guiding device inside the storage tank, ensuring that the electrolyte drawn to the fuel cell module for reaction is unmixed, thereby ensuring the normal progress of the charge and discharge reaction.

[0025] The above description is only the basic principle and preferred embodiment of this utility model. Any improvements and substitutions made by those skilled in the art based on this utility model shall fall within the protection scope of this utility model.

Claims

1. A flow guiding device for an electrolyte storage tank in a flow energy storage system, characterized in that: The device includes an upper guide plate, a middle guide plate, and a bottom guide plate arranged in layers within the electrolyte storage tank. The middle guide plate includes a horizontal plate and a vertical plate connected to one side of the horizontal plate. The uppermost end of the vertical plate extends beyond the overflow liquid surface. Spaces are provided between the vertical plates of the upper and middle guide plates, as well as between the middle guide plate and the inner wall of the electrolyte storage device, forming an overflow electrolyte buffer space among the upper, middle, and bottom guide plates. A liquid distribution guide plate is provided on one side of the bottom guide plate, and a flow control mechanism that closes or opens according to the overflow electrolyte pressure is provided between the bottom guide plate and the liquid distribution guide plate. The liquid distribution guide plate has holes for a suction pipe to pass through, and the liquid distribution pipe is located below the liquid distribution guide plate.

2. The electrolyte storage tank diversion device for a flow storage system according to claim 1, characterized in that: The flow control mechanism includes a baffle, a rotating shaft, and a spring. The bottom of the baffle is rotatably connected to the bottom guide plate via the rotating shaft. The top of the baffle is closed at the bottom of the middle guide plate or opened and pressed against the liquid distribution guide plate. The spring is located between the bottom of the baffle and the bottom guide plate.

3. The electrolyte storage tank diversion device for a flow storage system according to claim 1, characterized in that: The side of the electrolyte storage device with the overflow hole is called the overflow side. The two sides connected to the overflow side are called the front side and the rear side. The upper guide plate and the lower guide plate are connected to the inner wall of the overflow side, the inner wall of the front side, and the inner wall of the rear side. The middle guide plate is connected to the inner wall of the front side and the inner wall of the rear side.

4. The electrolyte storage tank diversion device for a flow storage system according to claim 1, characterized in that: The upper, middle, and lower baffles are plate-like structures with flat surfaces on both the top and bottom.

5. The electrolyte storage tank diversion device for a flow storage system according to claim 2, characterized in that: The end of the liquid distribution guide plate facing the flow control mechanism is an inclined plate.

6. The electrolyte storage tank diversion device for a flow storage system according to claim 1, characterized in that: This device is installed in the negative electrode storage tank.

7. The electrolyte storage tank diversion device for a flow storage system according to claim 1, characterized in that: The electrolyte storage tank is a square or cylindrical tank.

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