All-vanadium redox flow battery stack liquid inlet and outlet plate structure

Abstract

The utility model discloses a kind of all-vanadium redox flow battery stack liquid inlet and outlet plate structure, including plate body, plate body inside is equipped with built-in serpentine flow channel along plate body extension, the side of plate body is equipped with liquid inlet and liquid outlet, liquid inlet, liquid outlet respectively with the both ends of the serpentine flow channel communication, plate body is equipped with flow channel interface with single cell electrolyte inlet corresponding and sealable communication towards the side of all-vanadium redox flow battery stack single cell, to replace the coil structure arranged outside the stack by built-in serpentine flow channel.This liquid inlet and outlet plate will be built-in serpentine flow channel, shorten the invalid transmission path of electrolyte between stack, reduce the driving force of ion directional migration, inhibit bypass current generation on structure;And cancel external coil by plate body built-in serpentine flow channel, save a lot of external pipeline and pipe joint, simplify system pipeline layout, reduce raw material procurement and assembly cost, while reducing the number of sealing node, greatly improve sealing reliability, reduce electrolyte leakage risk from the root.

Description

Technical Field

[0001] This utility model relates to the field of vanadium redox flow battery stack technology, specifically to a vanadium redox flow battery stack inlet and outlet liquid plate structure. Background Technology

[0002] A typical vanadium redox flow battery consists of a power unit (stack), an energy storage unit (vanadium electrolyte and storage tank), and a vanadium electrolyte delivery unit (pipelines, valves, circulation pumps, heat exchangers, etc.). The vanadium redox flow battery stack is usually secured by end plates that fasten the inlet / outlet plates, current collectors, and multiple individual cells. Each individual cell typically consists of positive and negative electrode frames, positive and negative electrodes, a proton exchange membrane, bipolar plates, and seals. The positive and negative electrodes of a single cell are housed within their respective frames, separated by the proton exchange membrane for hydrogen ion conduction; the positive and negative electrodes of a single cell are separated from the negative electrode of the preceding cell and the positive electrode of the following cell, respectively, by bipolar plates for electron conduction.

[0003] Currently, in the integrated design of vanadium redox flow battery systems, the use of a common flow channel for electrolyte delivery and distribution can lead to potential differences between the stacks causing ion migration in the electrolyte, resulting in bypass current. Bypass current not only reduces the system's energy efficiency but also jeopardizes the safety of the entire battery system. Commonly used methods include extending the length or inner diameter of the branch pipes between the main pipeline and each stack, and designing a back-and-forth winding design around each stack. This approach results in a complex piping system with numerous pipe joints, high production costs, large size, low sealing reliability, and a high risk of leakage. Furthermore, if the inner piping leaks, maintenance becomes extremely difficult.

[0004] In order to reduce bypass current, traditional vanadium redox flow battery energy storage systems have added serpentine pipes at the inlet and outlet of the stack, which is the currently common coil arrangement. For the coil arrangement with coils on all sides, the coils need to be fixed on the stack support before piping is installed. This not only makes the installation of branch pipes inconvenient, but also requires sufficient operating space at the bottom, resulting in a significant increase in the system height. Utility Model Content

[0005] To address the aforementioned technical problems, this utility model provides an inlet / outlet liquid plate structure and a vanadium redox flow battery stack.

[0006] The technical solution of this utility model to solve the above-mentioned technical problems is as follows: a liquid inlet and outlet plate structure for a vanadium redox flow battery stack, including a plate body, an internal serpentine flow channel extending along the plate body, and a liquid inlet and a liquid outlet on the side of the plate body, which are respectively connected to the two ends of the serpentine flow channel. The plate has a flow channel interface on the side facing the single cell of the vanadium redox flow battery stack, which corresponds to and can be sealed and connected to the electrolyte inlet of the single cell, so as to replace the coil structure set on the outside of the stack with the built-in serpentine flow channel.

[0007] Furthermore, the serpentine flow channel is a U-shaped flow channel, and the U-shaped flow channel is arranged in a zigzag pattern along the extension direction of the plate.

[0008] Furthermore, each of the opposite sides of the plate is provided with a set of liquid inlets and a set of liquid outlets. The two sets of liquid inlets are connected by the main liquid inlet path of the serpentine flow channel, and the two sets of liquid outlets are connected by the main liquid outlet path of the serpentine flow channel.

[0009] Furthermore, an annular sealing groove is provided on the side of the plate facing the single cell. The annular sealing groove surrounds the flow channel interface to achieve a sealed connection between the flow channel interface and the electrolyte inlet of the single cell.

[0010] Furthermore, the cross-sectional shape of the serpentine flow channel is circular, rectangular, or a regular polygon.

[0011] Furthermore, both the inlet and the outlet are integrally formed with a pipe fitting mounting part, the inner wall of the pipe fitting mounting part is provided with an internal thread, and the connection between the pipe fitting mounting part and the serpentine flow channel is provided with a chamfer transition structure to reduce the electrolyte flow resistance.

[0012] The present invention has the following beneficial effects: The present invention provides a liquid inlet and outlet plate structure for a vanadium redox flow battery stack: (1) The inlet and outlet plates have a built-in serpentine flow channel, which shortens the ineffective transport path of electrolyte between the stacks, reduces the driving force for ion directional migration, and structurally suppresses the generation of bypass current, thereby improving the energy conversion efficiency of the vanadium redox flow battery system, while avoiding the system safety risks caused by bypass current. (2) This inlet and outlet plate eliminates the need for external coils by using a built-in serpentine flow channel, saving a large number of external pipes and pipe joints, simplifying the system pipeline layout, and reducing the cost of raw material procurement and assembly; at the same time, it reduces the number of sealing nodes, greatly improves sealing reliability, and reduces the risk of electrolyte leakage from the source. (3) The serpentine flow channel of this inlet and outlet plate has a U-shaped structure and is compactly arranged inside the plate body. This ensures the stable flow and uniform distribution of electrolyte in the flow channel, meets the electrolyte supply requirements of a single cell, and does not require additional space outside the plate body. This further enhances the structural simplicity and space utilization of the inlet and outlet plate, and provides support for the overall assembly stability of the stack. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a side view of the present invention; Figures 1 to 2 The reference numerals in the attached figures are: 1-plate, 2-serpentine flow channel. Detailed Implementation

[0014] The principles and features of this utility model are described below with reference to the accompanying drawings. The examples given are only for explaining this utility model and are not intended to limit the scope of this utility model.

[0015] like Figures 1 to 2 As shown, a vanadium redox flow battery stack inlet and outlet plate structure includes a plate body 1, with an internal serpentine flow channel 2 extending along the plate body 1. The plate body 1 serves as the basic structural carrier for the inlet and outlet plates, providing installation and accommodating space for the internal serpentine flow channel 2, the inlet, the outlet, and the flow channel interface, ensuring the integrated layout of various functional components. Furthermore, during stack assembly, the plate body 1 must cooperate with the end plates, current collectors, and individual cells. The end plates' fastening action maintains the stability of the overall stack structure while adapting to the internal assembly dimensions of the stack, ensuring precise docking with the individual cells and current collectors. By providing the serpentine flow channel 2 extending along the plate body 1, the flow path of the electrolyte within the inlet and outlet plates is extended, reducing the directional migration of electrolyte ions caused by potential differences between stacks, thereby suppressing bypass current generation. Additionally, the compact design of the serpentine flow channel 2 avoids the tangled layout of external pipelines, simplifying the pipeline structure of the stack system and reducing the space occupied by the pipelines.

[0016] The plate 1 has an inlet and an outlet on its side, which are connected to both ends of the serpentine flow channel 2. The inlet and outlet serve as channels for the electrolyte to enter and exit the inlet / outlet plates, respectively, and are both located on the side of the plate 1 (avoiding the end plate fastening area to prevent interference with the fuel cell assembly). The inlet receives vanadium electrolyte from an external delivery unit (such as a circulating pump) and guides it into the built-in serpentine flow channel 2; the outlet discharges the electrolyte after it has flowed through the serpentine flow channel 2 and delivers it to the electrolyte inlet of the single cell, thus achieving orderly transfer of electrolyte between the inlet / outlet plates and the single cell.

[0017] The plate 1 has a flow channel interface on the side facing the single cell of the vanadium redox flow battery stack, which corresponds to and is sealably connected to the electrolyte inlet of the single cell. This allows the built-in serpentine flow channel 2 to replace the external coil structure of the stack. The flow channel interface achieves precise and sealed connection between the built-in serpentine flow channel 2 and the electrolyte inlet of the single cell. Through the corresponding design with the electrolyte inlet of the single cell, it ensures that the electrolyte can flow stably into the single cell from the serpentine flow channel 2, meeting the electrode reaction requirements of the single cell. At the same time, the sealed connection characteristic can prevent electrolyte leakage during the transmission process, ensuring the sealing and safety of the stack system.

[0018] In this embodiment, the serpentine flow channel 2 is a U-shaped flow channel. The U-shaped flow channel is arranged in a zigzag pattern along the extension direction of the plate 1. Its compact zigzag structure extends the flow path of the electrolyte within the plate 1, reducing the directional migration of electrolyte ions caused by potential differences between different fuel cells (the ion migration distance is shortened and the path is controllable, reducing the driving force for directional migration). Structurally, it suppresses the generation of bypass current, avoiding energy loss and system safety risks. On the other hand, the cross-section (circular, rectangular, or regular polygon) of the U-shaped flow channel is adapted to the electrolyte flow characteristics, reducing flow resistance and ensuring stable electrolyte transport within the flow channel, avoiding uneven transport caused by excessively high local flow rates or stagnation. The cross-sectional shape of the serpentine flow channel 2 is circular, rectangular, or regular polygonal.

[0019] In this embodiment, a set of liquid inlets and outlets are respectively provided on both opposite sides of the plate 1. The two sets of liquid inlets are connected by the main liquid inlet path of the serpentine flow channel 2, and the two sets of liquid outlets are connected by the main liquid outlet path of the serpentine flow channel 2. The two sets of liquid inlets connected by the main liquid inlet path can simultaneously receive vanadium electrolyte from external delivery units (such as circulating pumps) of the fuel cell stack. Compared with a single liquid inlet, dual input can increase the input flow rate of electrolyte per unit time, avoiding electrolyte supply lag caused by insufficient flow rate of a single input path. The main liquid inlet path can evenly merge the two electrolyte paths and distribute them to each branch of the serpentine flow channel 2, ensuring that the electrolyte can be quickly and sufficiently delivered to the entire flow channel area, providing sufficient "raw materials" for subsequent flow into the single cell. The electrolyte flowing through the serpentine flow channel 2 is collected through the main liquid outlet path and discharged to the single cell from the two sets of outlets. The main outlet can balance the electrolyte pressure and flow rate of each branch of the flow channel, avoiding uneven electrolyte distribution caused by excessively fast or slow local flow rates; the dual outlets can stably deliver the collected electrolyte to different areas of the single cell (such as the inlets corresponding to the positive and negative electrode frames), ensuring that each electrode reaction site in the single cell can receive a uniform electrolyte supply, avoiding a decrease in single cell reaction efficiency due to local electrolyte shortage, and ensuring stable overall power output of the stack.

[0020] In addition, the two sets of inlet / outlet ports and the main line connection design form a "dual redundancy" structure: if one set of inlet or outlet ports cannot work properly due to pipeline blockage, connector failure or other problems, the other set of interfaces can continue to realize the input and output of electrolyte through the main line, avoiding the entire stack from stopping operation due to a single interface failure, greatly improving the fault tolerance of the stack system, and reducing the risk of overall shutdown caused by local failure.

[0021] In this embodiment, an annular sealing groove is provided on the side of plate 1 facing the single cell. The annular sealing groove surrounds the flow channel interface to achieve a sealed connection between the flow channel interface and the electrolyte inlet of the single cell. The sealing effect of the annular sealing groove ensures the "directional transmission" of the electrolyte. During the process of electrolyte flowing from the flow channel interface into the electrolyte inlet of the single cell, no leakage means that all electrolyte can enter the single cell. This avoids the waste of raw materials caused by electrolyte leakage and ensures that the single cell receives a sufficient supply of vanadium ions to meet the requirements of electrode reaction for electrolyte flow rate and concentration. It also prevents the decrease in single cell reaction efficiency caused by insufficient electrolyte supply, thereby ensuring the overall energy conversion efficiency of the stack. In addition, the annular sealing groove is a "built-in" design, located on the side of plate 1 facing the single cell. During stack assembly, only the sealing element needs to be embedded in the groove, and then the inlet and outlet plates are fastened to the single cell through the end plate according to the conventional process. There is no need for additional complicated operations such as pipe winding and sealant application.

[0022] In this embodiment, both the inlet and outlet are integrally formed with pipe fitting mounting parts. The inner wall of the pipe fitting mounting part is provided with internal threads, and the connection between the pipe fitting mounting part and the serpentine flow channel 2 is provided with a chamfered transition structure to reduce electrolyte flow resistance. The pipe fitting mounting part is integrally formed with the plate body 1, eliminating the need for additional welding or assembly of pipe fitting components as required by traditional external coil structures, thus reducing the number of parts and operation steps in the fuel cell stack piping assembly. At the same time, the internal thread design allows for direct "threaded engagement" with the external threaded connectors of the external delivery pipeline, eliminating the need for complex flange connections or clamp fixation. Operators only need to tighten the threads using conventional tools, significantly reducing the difficulty of pipeline connection.

[0023] Additionally, it should be noted that components not described in detail in this article are existing technologies.

[0024] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A vanadium redox flow battery stack inlet and outlet liquid plate structure, characterized in that, Includes a plate (1), the plate (1) has an internal serpentine flow channel (2) extending along the plate (1), the side of the plate (1) has an inlet and an outlet, the inlet and outlet are respectively connected to the two ends of the serpentine flow channel (2); The plate (1) has a flow channel interface on the side facing the single cell of the vanadium redox flow battery stack that corresponds to and can be sealed and connected to the electrolyte inlet of the single cell, so as to replace the coil structure set outside the stack with the built-in serpentine flow channel (2).

2. The vanadium redox flow battery stack inlet / outlet liquid plate structure according to claim 1, characterized in that, The serpentine flow channel (2) is a U-shaped flow channel, and the U-shaped flow channel is arranged in a bent manner along the extension direction of the plate (1).

3. The vanadium redox flow battery stack inlet / outlet liquid plate structure according to claim 1, characterized in that, The plate (1) has a set of liquid inlets and a set of liquid outlets on its opposite sides. The two sets of liquid inlets are connected through the main liquid inlet path of the serpentine flow channel (2), and the two sets of liquid outlets are connected through the main liquid outlet path of the serpentine flow channel (2).

4. The vanadium redox flow battery stack inlet / outlet liquid plate structure according to claim 1, characterized in that, The plate (1) has an annular sealing groove on the side facing the single battery. The annular sealing groove surrounds the flow channel interface to achieve a sealed connection between the flow channel interface and the electrolyte inlet of the single battery.

5. The vanadium redox flow battery stack inlet / outlet liquid plate structure according to claim 1, characterized in that, The cross-sectional shape of the serpentine channel (2) is circular, rectangular or regular polygonal.

6. The vanadium redox flow battery stack inlet / outlet liquid plate structure according to claim 1, characterized in that, Both the inlet and outlet are integrally formed with a pipe fitting mounting part. The inner wall of the pipe fitting mounting part is provided with an internal thread, and the connection between the pipe fitting mounting part and the serpentine flow channel (2) is provided with a chamfer transition structure to reduce the flow resistance of the electrolyte.

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