An electrolyte storage tank of a secondary battery and a flow battery energy storage system

Abstract

The application relates to the field of electrochemical energy storage technology, in particular to an electrolyte storage tank of a secondary battery and a liquid flow battery energy storage system. The electrolyte storage tank comprises a box body and at least two turbulence rib plates arranged in the box body, the turbulence rib plates are spatial curved surface partitions, three-dimensional flow channels are arranged on the two sides of the spatial curved surface partitions respectively, a confluence cavity is arranged at the upper portion of the inner cavity of the box body, a distribution cavity is arranged at the bottom of the inner cavity of the box body, the confluence cavity and the distribution cavity are communicated through the three-dimensional flow channels, the confluence cavity is connected with a liquid outlet, and a backflow port is arranged on one side of the distribution cavity. The spatial curved surface partitions formed in a specific mode are arranged in parallel in the box body to form meandering three-dimensional flow channels with uniform cross sections, the electrolyte is forced to turn when flowing through the three-dimensional flow channels, strong radial microcirculation is generated, passive mixing with high efficiency and no dead zone and wall self-cleaning are realized, the active material deposition is fundamentally prevented, and the mixing effect and the deposition prevention capacity are favorably ensured.

Description

Technical Field

[0001] This invention relates to the field of electrochemical energy storage technology, and in particular to an electrolyte storage tank for a secondary battery and a flow battery energy storage system. Background Technology

[0002] Flow batteries, especially vanadium redox flow batteries, have broad application prospects in large-scale energy storage due to their advantages such as independently designable power and capacity, long lifespan, and high safety. Their electrolyte is stored in an external tank and circulated between the tank and the battery stack via a pump.

[0003] As energy storage scales up, electrolyte storage tank volumes can reach tens to hundreds of cubic meters. Existing large storage tanks are typically simple containers lacking effective fluid guidance and mixing structures, leading to dead zones in the electrolyte flow within the tank. This not only reduces the effective utilization rate of the electrolyte but also causes localized electrolyte stagnation, resulting in uneven concentration and temperature of active materials. Under long-term operation, this can easily trigger side reactions or vanadate precipitation. Precipitates can clog pipes and contaminate the membrane electrodes of the fuel cell stack, severely damaging system performance and lifespan. Furthermore, traditional vertical or horizontal cylindrical storage tanks are difficult to deploy in confined spaces such as standard shipping containers, resulting in low space utilization and hindering modular deployment. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an electrolyte storage tank and energy storage system for secondary batteries, which addresses the above-mentioned technical deficiencies by adopting an innovative internal flow channel structure and active anti-deposition design, thereby solving the problems of uneven mixing, easy precipitation, low space utilization and inconvenient expansion in large storage tanks.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: an electrolyte storage tank for a secondary battery, comprising a tank body and at least two baffles disposed in the tank body. The baffles are spatial curved surface partitions, and three-dimensional flow channels are respectively provided on both sides of the spatial curved surface partitions. A confluence cavity is provided at the upper part of the inner cavity of the tank body, and a distribution cavity is provided at the bottom of the inner cavity of the tank body. The confluence cavity and the distribution cavity are connected through the three-dimensional flow channels. The confluence cavity is connected to an outlet, and a return port is provided on one side of the distribution cavity.

[0006] To further optimize this technical solution, the surface of each spatial curved partition is composed of two sets of parallel, periodically undulating wave lines as reference lines. The peaks of the first set of wave lines are connected to the corresponding troughs of the second set of wave lines, and the troughs of the first set of wave lines are connected to the corresponding peaks of the second set of wave lines, thus forming a periodically meandering spatial curved surface.

[0007] To further optimize this technical solution, at least two spatial curved surface baffles are arranged parallel to each other in the box, and the waveform phases of any two adjacent spatial curved surface baffles are consistent, so that the peak of one baffle is directly opposite the peak of the adjacent baffle in the horizontal projection, and the trough is directly opposite the trough, thereby forming a three-dimensional flow channel with a basically constant cross-sectional width and a wavy, meandering centerline between the adjacent baffles.

[0008] To further optimize this technical solution, the average distance W between two adjacent spatial curved partitions satisfies the relationship between the wave height H of the spatial curved partition: 1.5H ≤ W ≤ 3H, where the wave height H is the vertical distance between the wave crest and the wave trough within one waveform period.

[0009] To further optimize this technical solution, the wavelength λ of the spatial curved partition satisfies: W ≤ λ ≤ 2W.

[0010] To further optimize this technical solution, the bottom of the manifold is provided with a top opening that communicates with the three-dimensional flow channel, and the top of the distribution cavity is provided with a lower opening that communicates with the three-dimensional flow channel. The vertical projection positions of the top opening and the lower opening are arranged alternately.

[0011] To further optimize this technical solution, an immersion pipe extending into the tank is connected to the lower part of the outlet. The inlet end of the immersion pipe is located in the top manifold and is lower than the lowest working liquid level of the top manifold.

[0012] To further optimize this technical solution, a micro-circulation capillary network is pre-embedded inside the spatial curved partition. The micro-circulation capillary network includes a main pipe and branch pipes. The main pipe is located in the middle of the spatial curved partition. A flushing hole is provided in the recess of the spatial curved partition. The main pipe is connected to the flushing hole through the branch pipe. A micro-circulation liquid pump is provided outside the box. One end of each main pipe is connected to the outlet side of the micro-circulation liquid pump through a connecting hose. The inlet side of the micro-circulation liquid pump is connected to the distribution chamber.

[0013] Further optimization of this technical solution also includes a micro-circulation control system. The box is equipped with temperature sensors for monitoring the temperature of each three-dimensional flow channel. The bottom end of the main pipe extends out of the outside of the box. A regulating valve is installed on the outside of the box at the position corresponding to the main pipe. The regulating valve is connected to the connecting pipeline between the main pipe and the micro-circulation pump. The control system is configured to independently adjust the opening degree of the regulating valve corresponding to each spatial curved surface partition according to the signal of each temperature sensor.

[0014] The present invention also provides a flow battery energy storage system, including a stack, a circulating pump and a piping system, and multiple electrolyte storage tanks for the aforementioned secondary batteries. The outlets of each storage tank are connected in parallel through an outlet header, and the return ports of each storage tank are connected in parallel through a return header, forming a modularly expandable storage tank array.

[0015] Compared with existing technologies, this invention has the following advantages: 1. The spatial curved surface baffles, constructed in a specific manner, are arranged in parallel within the tank to form a meandering three-dimensional flow channel with a uniform cross-section. When the electrolyte flows through, it is forced to change direction, generating a strong radial micro-circulation. This achieves efficient, dead-zone-free passive mixing and wall self-cleaning, fundamentally preventing the deposition of active substances. This structure effectively guarantees the mixing effect and anti-deposition capability; 2. The mixing energy comes entirely from the main circulation pump. The spatial curved surface baffles are a static structure with no moving parts, eliminating the risk of dynamic seal leakage. This structure effectively ensures the system's high reliability and low operating energy consumption; 3. The independent microcirculation system integrated inside the partition can actively and directionally flush the partition surface with high intensity, and combined with temperature sensing, it can achieve precise zone control. This structure effectively ensures enhanced anti-deposition capability and system adaptability under harsh working conditions such as easy crystallization; 4. The openings of the manifold and distribution chamber adopt an alternating arrangement design, which disrupts the directionality of the fluid and promotes the mixing of electrolyte between different flow channels. This structure effectively improves the uniformity of electrolyte distribution and manifold, and enhances the overall performance. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the external structure of an electrolyte storage tank for a secondary battery. Figure 2 This is a schematic diagram of the internal main view structure of an electrolyte storage tank for a secondary battery. Figure 3 This is a schematic diagram of the internal structure of an electrolyte storage tank for a secondary battery. Figure 4 This is a schematic diagram of the structure of a spatial curved partition. Figure 5 This is a top view of a schematic diagram of a spatial curved partition. Figure 6 This is a diagram showing the positional relationship between the top opening and the bottom opening in an electrolyte storage tank for a secondary battery.

[0017] In the diagram: 1. Box body; 2. Spatial curved partition; 3. Micro-circulation liquid pump; 11. Manifold; 12. Distribution chamber; 13. Gas phase space; 20. Three-dimensional flow channel; 22. Main pipe; 110. Liquid outlet; 111. Top opening; 112. Immersion pipe; 120. Return port; 121. Bottom opening; 220. Flushing hole; 221. Regulating valve; 222. Branch pipe. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0019] Example 1 like Figure 1 and Figure 3 As shown, the electrolyte storage tank for a secondary battery according to the present invention is mainly a sealed box 1. The box 1 is preferably made of a plastic resistant to strong acid corrosion, such as modified polypropylene (PPH), and is integrally formed by rotational molding or welding to ensure no risk of weld leakage. Multiple spatial curved surface partitions 2 are arranged parallel to each other along the width direction inside the box 1. In this embodiment, there are seven spatial curved surface partitions 2, which divide the inner cavity of the box 1 into eight independent three-dimensional flow channels 20. The top of the inner cavity of the box 1 is closed to form a manifold 11, and the bottom is closed to form a distribution cavity 12. The manifold 11 is connected to an outlet 110 leading to the outside of the box 1, and the side of the distribution cavity 12 is connected to a return port 120.

[0020] Combination Figure 2 , Figure 3 and Figure 4 Each spatial curved surface baffle 2 is defined by a specific mathematical and geometric method: using two sets of parallel wavy lines with the same sinusoidal waveform in space as reference lines, a point (wave crest) on one set of lines is connected to a corresponding periodic point (wave trough) on the other set of lines with a smooth curved surface, thus forming a three-dimensional spatial curved surface that exhibits a periodic, undulating shape. Multiple such spatial curved surface baffles 2 are arranged in parallel with their waveforms aligned in phase, i.e., wave crests aligning with wave crests and wave troughs aligning with wave troughs. Thus, between any two adjacent spatial curved surface baffles 2, a three-dimensional flow channel 20 with a roughly uniform cross-sectional width but a centerline extending along a wavy, meandering pattern is naturally formed. The upper end of the three-dimensional flow channel 20 is connected to the confluence cavity 11, and the lower end is connected to the distribution cavity 12.

[0021] Combination Figure 1 As shown, the wave height of the spatial curved baffle 2 itself is defined as H (the vertical distance from the crest to the trough of a complete waveform), and the wavelength is defined as λ (the horizontal distance between adjacent crests). The average distance between two adjacent spatial curved baffles 2 is defined as W. Preferably, W and H satisfy 1.5H≤W≤3H, more preferably W≈2H; λ satisfies W≤λ≤2W. For example, H=40mm, W=80mm, and λ=100mm can be taken. This parameter range can maintain reasonable flow resistance and achieve the best balance under the premise of inducing strong secondary flow and good mixing effect, resulting in low pump consumption.

[0022] like Figure 2 and Figure 5 As shown, to ensure uniform entry and exit of the electrolyte into each of the three-dimensional flow channels 20, the bottom of the manifold 11 is provided with multiple top openings 111, and the top of the distribution chamber 12 is provided with multiple lower openings 121. These openings are preferably designed as elongated slots. An important optimization design is that the top openings 111 and the lower openings 121 are staggered in the vertical direction (top view projection). This staggered layout can further disrupt the directionality of the fluid, promote electrolyte mixing, and improve overall uniformity.

[0023] The lower part of the outlet 110 is connected to an immersion pipe 112 extending vertically into the tank 1. The inlet end of the immersion pipe 112 must always be lower than the preset minimum working liquid level of the storage tank during operation, thereby ensuring that no matter how the liquid level fluctuates, the main circulation pump can only draw pure liquid from the inlet of the immersion pipe 112, effectively preventing gas from being sucked into the pump and causing cavitation, and ensuring the safe operation of the main circuit. A gas phase space 13 is reserved at the top of the tank 1, filled with inert gas and maintained at a slight positive pressure, to balance the volume changes of the electrolyte due to thermal expansion and contraction and to isolate oxygen.

[0024] To further enhance anti-deposition capabilities, especially reliability under low-temperature, easily crystallizing conditions, this invention incorporates an active microcirculation subsystem. A microcirculation capillary network is pre-embedded within each spatial curved partition 2 during manufacturing. This network comprises a main pipe 22 running along the center of the partition and numerous branch pipes 222 connected to it. Multiple small flushing holes 220 are formed or opened at the concave areas (troughs) of the curved surface of the spatial curved partition 2, and the branch pipes 222 communicate with these flushing holes 220. The bottom ends of all the main pipes 22 protrude from the underside of the housing 1. A microcirculation pump 3 is installed outside the housing 1. The pump's inlet is connected to the distribution chamber 12 via a pipe, and its outlet is connected to the bottom ends of the corresponding main pipes 22 of each spatial curved partition 2 via multiple connecting hoses. A regulating valve 221 is installed on each connecting hose. Furthermore, a temperature sensor is installed inside the housing 1 in the area corresponding to each spatial curved partition 2.

[0025] The microcirculation subsystem operates as follows: Microcirculation pump 3 starts, drawing electrolyte from distribution chamber 12, pressurizing it, and pumping it into each main pipe 22. The electrolyte is then ejected at high speed from each flushing hole 220 via branch pipes, directly flushing the wall surface of the curved spatial partition 2. This high-speed stream effectively disturbs the boundary layer of the wall, carrying away tiny crystal nuclei that may begin to deposit, and mixes with the electrolyte in the main channel 20 before flowing upwards into the confluence chamber 11. The microcirculation control system monitors the signals from each temperature sensor in real time. When the temperature of a region of the curved spatial partition 2 falls below a set threshold, indicating an increased risk of crystallization, the control system increases the opening of the regulating valve 221 on the corresponding branch, increasing the flushing flow to that partition, achieving zoned and precise anti-crystallization control. This system is independent of the main circulation; its flow rate and pressure can be flexibly set as needed, providing strong anti-deposition capabilities.

[0026] Example 2 This invention also provides a flow battery energy storage system. The system includes a fuel cell stack, a main circulation pump, piping, and a control system, and integrates multiple electrolyte storage tanks. The outlets 110 of each tank are connected in parallel to a common outlet header, and then pumped to the fuel cell stack via the main circulation pump. Electrolyte returning from the fuel cell stack is distributed to the return ports 120 of each tank via a common return header. The micro-circulation subsystems of each tank can be controlled uniformly or independently. This modular design allows the energy storage system to flexibly increase or decrease the number of tanks according to capacity requirements, like building blocks, greatly improving the convenience and economy of engineering deployment.

[0027] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An electrolyte storage tank for a secondary battery, comprising a tank body (1) and at least two baffles disposed within the tank body, characterized in that: The turbulence rib is a spatial curved surface partition (2). The two sides of the spatial curved surface partition (2) are respectively provided with three-dimensional flow channels (20). The upper part of the inner cavity of the box (1) is provided with a confluence cavity (11). The bottom of the inner cavity of the box (1) is provided with a distribution cavity (12). The confluence cavity (11) and the distribution cavity (12) are connected through the three-dimensional flow channels (20). The confluence cavity (11) is connected with a liquid outlet (110). The side of the distribution cavity (12) is provided with a return port (120).

2. The electrolyte storage tank for a secondary battery according to claim 1, characterized in that: Each of the spatial curved partitions (2) is composed of two sets of parallel, periodically undulating wave lines as reference lines. The peaks of the first set of wave lines are connected to the corresponding troughs of the second set of wave lines, and the troughs of the first set of wave lines are connected to the corresponding peaks of the second set of wave lines, thus forming a periodically meandering spatial curved surface.

3. The electrolyte storage tank for a secondary battery according to claim 2, characterized in that: At least two spatial curved surface partitions (2) are arranged parallel to each other in the box (1), and the waveform phases of any two adjacent spatial curved surface partitions (2) are consistent, so that the peak of one partition is directly opposite the peak of the adjacent partition in the horizontal projection, and the trough is directly opposite the trough, thereby forming a three-dimensional flow channel (20) with a basically constant cross-sectional width and a wavy meandering centerline between the adjacent partitions.

4. The electrolyte storage tank for a secondary battery according to claim 2, characterized in that: The average distance W between two adjacent spatial curved partitions (2) satisfies the relationship with the wave height H of the spatial curved partition (2): 1.5H≤W≤3H, where the wave height H is the vertical distance between the wave crest and the wave trough within one waveform period.

5. The electrolyte storage tank for a secondary battery according to claim 2, characterized in that: The wavelength λ of the spatial curved partition satisfies: W≤λ≤2W.

6. The electrolyte storage tank for a secondary battery according to claim 1, characterized in that: The bottom of the manifold (11) is provided with a top opening (111) that communicates with the three-dimensional flow channel (20), and the top of the distribution cavity (12) is provided with a lower opening (121) that communicates with the three-dimensional flow channel (20). The projection positions of the top opening (111) and the lower opening (121) are arranged alternately.

7. The electrolyte storage tank for a secondary battery according to claim 1, characterized in that: The lower part of the outlet (110) is connected to an immersion pipe (112) extending into the interior of the box (1). The inlet end of the immersion pipe (112) is located inside the manifold (11) and is lower than the lowest working liquid level of the top manifold (11).

8. The electrolyte storage tank for a secondary battery according to claim 1, characterized in that: A micro-circulation capillary network is pre-embedded inside the spatial curved partition (2). The micro-circulation capillary network includes a main pipe (22) and branch pipes (221). The main pipe (22) is located in the middle of the spatial curved partition (2). A flushing hole (220) is provided in the recess of the spatial curved partition (2). The main pipe (22) is connected to the flushing hole (220) through the branch pipe (221). A micro-circulation liquid pump (3) is provided outside the box (1). One end of each main pipe (22) is connected to the outlet side of the micro-circulation liquid pump (3) through a connecting hose. The inlet side of the micro-circulation liquid pump (3) is connected to the distribution chamber (12).

9. The electrolyte storage tank for a secondary battery according to claim 8, characterized in that: It also includes a micro-circulation control system. The housing (1) is equipped with a temperature sensor for monitoring the temperature of each of the three-dimensional flow channels (20). The bottom end of the main pipe (22) extends out of the outside of the housing (1). An regulating valve (221) is provided on the outside of the housing (1) at the position corresponding to the main pipe (22). The regulating valve (221) is connected in the connecting pipeline between the main pipe (22) and the micro-circulation pump (3). The control system is configured to independently adjust the opening degree of the regulating valve (221) corresponding to each of the spatial curved partitions (2) according to the signal of each of the temperature sensors.

10. A flow battery energy storage system, characterized in that, It includes a fuel cell stack, a circulating pump and a piping system, and also includes multiple electrolyte storage tanks for secondary batteries as described in any one of claims 1-9. The outlets (110) of each storage tank are connected in parallel through an outlet header, and the return ports (120) of each storage tank are connected in parallel through a return header, forming a modularly extended storage tank array.

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