Flow battery system

Abstract

The present invention relates to the technical field of flow batteries, and discloses a flow battery system, the flow battery system comprises a main liquid storage tank and at least one flow battery unit, each flow battery unit comprises at least one flow battery module, a liquid inlet pipeline and a liquid outlet pipeline of an electric pile of the flow battery module are respectively provided with an electrolyte transmission device, each electrolyte transmission device comprises an interflow liquid storage structure, a cylinder body and a cavity body formed by surrounding the cylinder body, and the cylinder body is provided with a pressure regulating port, an upper liquid inlet and a lower liquid outlet; the intermittent flow liquid storage structure is arranged to be rotatable, is mounted in the cavity, is positioned below the upper liquid inlet and is used for receiving the electrolyte, the intermittent flow liquid storage structure is provided with at least two hoppers which are arranged at an included angle, and when one hopper is in a receiving state, the other hopper is in a dumping state between two adjacent hoppers. The device has the advantage that the continuous flow of the electrolyte can be realized while no bypass current is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid flow batteries, and in particular to a liquid flow battery system. Background Art

[0002] The stack of a flow battery is composed of multiple single cells stacked together, with voltages connected in series, electrolytes connected in parallel, and a common flow channel. Due to the potential difference between the single cells. When the electrolyte flows in the stack, the ions in the electrolyte will migrate in a directional manner under the action of the potential difference. For example, in an all-vanadium flow battery, vanadium ions will move in the electrolyte channel between the positive and negative electrodes. The connecting pipes between the stacks and the common flow channels in the stacks have a certain conductivity, so these directional migrating ions will form a current in the pipes, that is, a bypass current. This bypass current does not pass through the normal load, which will cause energy loss and reduce the overall system efficiency of the battery.

[0003] Eliminating the common electrolyte channel or interrupting the electrolyte channel is the main idea to solve the problem. In the prior art, CN213340450U discloses a bubble breaker for a liquid flow battery, which forms bubbles in the channel to increase the effective resistance of the solution. The bubble method causes gas to enter the stack and cause irreversible damage to the exchange membrane; CN118553975B discloses a coil-heat dissipation integrated liquid flow battery stack inlet and outlet pipe structure, which uses a coil structure in the all-alum liquid flow battery, which increases the resistance and reduces the bypass current loss. The effect of reducing the bypass current loss of this technical solution is low; CN221508245U discloses an electrolyte interval transmitter and a bypass for a liquid flow battery. The bypass current interrupter adopts a piston structure to isolate the liquid inlet chamber and the liquid outlet chamber, thereby achieving the conductivity of the liquid in the blocking flow channel. The piston reciprocating structure of this technical solution prevents the fluid from flowing continuously; CN221708748U discloses a dual liquid flow battery bypass current interrupter, which adopts a two-stage liquid storage device. Its main interruption principle is to first use the lever principle to intermittently store the liquid in a temporary liquid storage mechanism, and then release the liquid to the lower liquid storage port by the siphon effect. The disadvantage of this technical solution is that the structure is complex and the liquid cannot be discharged continuously; the first and second stage siphons have the risk of intermittent flow failure. Summary of the invention

[0004] The purpose of the present invention is to overcome the problem in the prior art that the electrolyte transmission device cannot discharge liquid continuously, and to provide a liquid flow battery system, which has the advantage of ensuring no bypass current while achieving continuous flow of electrolyte.

[0005] In order to achieve the above object, the present invention provides a liquid flow battery system, the liquid flow battery system includes a main liquid storage tank and at least one liquid flow battery unit, each of the liquid flow battery units includes at least one liquid flow battery module, and an electrolyte transmission device is installed on the liquid inlet pipeline and the liquid outlet pipeline of the battery stack of the liquid flow battery module, and the electrolyte transmission device includes:

[0006] A cylinder and a cavity formed around the cylinder, wherein the cylinder is provided with a pressure regulating port, an upper liquid inlet and a lower liquid outlet;

[0007] The inter-flow liquid storage structure is configured to be rotatable, installed in the cavity and located below the upper liquid inlet for receiving electrolyte. The inter-flow liquid storage structure has at least two hoppers arranged at an angle, and between two adjacent hoppers, when one hopper is in a receiving state, the other hopper is in a dumping state.

[0008] Through the above technical scheme, the electrolyte transmission device used in the liquid flow battery system of the present invention can fundamentally realize intermittent flow, ensure that there is no bypass current while realizing continuous flow of electrolyte, and does not produce pulsed pressure and flow rate changes. Furthermore, the intermediate flow liquid storage structure of the electrolyte transmission device of the present invention is a purely mechanical structure, which reduces the cost and life risk of valve components. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a schematic structural diagram of an electrolyte transport device according to an embodiment of the present invention;

[0010] Figure 2 is a schematic structural diagram of an electrolyte transport device according to another embodiment of the present invention;

[0011] Figure 3 It is a schematic diagram of the appearance structure of an electrolyte transmission device according to one embodiment of the present invention;

[0012] Figure 4 yes Figure 2 Structural schematic diagram of the intermediate flow liquid storage structure;

[0013] Figure 5 is a schematic diagram of a flow battery system according to an embodiment of the present invention;

[0014] Figure 6 yes Figure 5 Left view of .

[0015] Description of Reference Numerals

[0016] 1 electrolyte transfer device; 2 flow battery module; 3 flow battery unit; 4 main liquid storage tank; 5 liquid inlet main pipe; 6 liquid return main pipe; 7 circulation pump; 10 upper liquid inlet; 11 mounting hole; 12 pressure regulating port; 13 upper cover; 14 intermediate flow liquid storage structure; 15 cylinder; 16 lower liquid outlet; 17 lower cover; 18 liquid level sensor installation port; 20 battery stack; 21 liquid outlet pipeline; 22 liquid inlet pipeline; 141 side baffle; 142 intermediate baffle. DETAILED DESCRIPTION

[0017] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0018] In the present invention, unless otherwise specified, directional words such as "up, down, left, right" used generally refer to up, down, left, right shown in the reference drawings; "inside and outside" refer to the inside and outside relative to the outline of each component itself; "top and bottom" are generally used to describe the relative positional relationship of each component in the direction shown in the drawings or in the vertical, perpendicular or gravity direction.

[0019] In order to solve the problem that the electrolyte transmission device in the prior art cannot discharge the electrolyte continuously, the present invention discloses a liquid flow battery system, such as Figure 5-Figure 6 As shown, the liquid flow battery system includes a main liquid storage tank 4 and at least one liquid flow battery unit 3, each liquid flow battery unit 3 includes at least one liquid flow battery module 2, and an electrolyte transmission device 1 is installed on the liquid inlet pipeline 22 and the liquid outlet pipeline 21 of the battery stack 20 of the liquid flow battery module 2, as shown in FIG. Figure 1-Figure 4 As shown, the electrolyte transfer device 1 comprises:

[0020] The cylinder 15 and the cavity formed around the cylinder 15 for storing electrolyte, the top of the cylinder 15 is provided with an upper liquid inlet 10, the bottom of the cylinder 15 is provided with a lower liquid outlet 16, the top of the cylinder 15 is provided with a pressure regulating port 12, the pressure regulating port 12 is connected to an air source through an air pipe installed with a pressure regulating device, so as to adjust the liquid level and ensure the continuous flow of the internal electrolyte. It can be understood that the liquid level adjustment and the flow rate adjustment of the electrolyte in the liquid flow battery can be achieved by adjusting the pressure in the cavity;

[0021] The inter-flow liquid storage structure 14 is rotatably installed in the cavity and is located below the upper liquid inlet 10 for receiving electrolyte. The inter-flow liquid storage structure 14 has at least two hoppers arranged at an angle. Between two adjacent hoppers, when one hopper is in a receiving state, the other hopper is in a dumping state. In this way, when the electrolyte enters the cavity through the upper liquid inlet 10, it will be continuously stored in one of the hoppers of the inter-flow liquid storage structure 14. When the hopper pours the liquid, the other hopper continues to receive the incoming liquid to ensure continuous liquid inflow. The liquid is poured at the bottom of the cavity, and a certain liquid level is ensured at the bottom of the cavity (for example, 40% to 60% of the liquid level of the cavity from bottom to top). Pressurized gas (for example, nitrogen with a pressure of 80kpa to 140kpa) is introduced through the pressure regulating port 12 to transmit fluid pressure, so that the electrolyte is continuously discharged through the lower liquid outlet 16. The inter-flow liquid storage structure 14 of the present invention can realize intermittent flow of electrolyte between the liquid flow battery stack and the common flow channel, ensuring that each energy storage liquid flow battery stack and the common flow channel are disconnected at the same time, avoiding bypass current of the liquid flow battery energy storage system, and improving the efficiency of the liquid flow energy storage system.

[0022] The support member can be set as a radial support rod fixedly connected to the inner wall of the cavity, and the interflow liquid storage structure 14 is sleeved on the support rod and can rotate around the support rod. Specifically, the interflow liquid storage structure 14 includes a hopper group, and the hopper group includes two fixedly connected hoppers. Among the two hoppers, the state in which the liquid inlet of one hopper is directly opposite to the upper liquid inlet 10 is used as a reference to rotate 10 to 20° to determine the position of the other hopper. Therefore, the hopper group has two hoppers at an angle of 20 to 40°. The shape and structure of these two hoppers are the same and are set to be large at the top and small at the bottom. The difference is the capacity. The support rod is installed in the middle and upper area of ​​the hopper with a larger capacity. In this way, as the hopper receives the inflow of electrolyte, the center of gravity changes and rotates around the support rod to pour the electrolyte into the cavity. Since the two hoppers are set at an angle of 20 to 40°, when one hopper is in a dumping state, the other hopper is in a receiving state.

[0023] The longitudinal cross-section of the hopper in the present invention has various shapes, such as semicircular, semi-elliptical or Figure 1 The trapezoid shown, Figure 1 As shown, a lifting lug can be installed on the top of the larger hopper in the hopper group, a support rod is passed through the lifting lug, and the unloaded centers of gravity of the two hoppers in the hopper group are respectively set on both sides of the support rod.

[0024] It should be noted that the interflow liquid storage structure 14 can also be set as Figure 2 , Figure 4The structure shown includes a plurality of baffles 142 extending outwards and arranged at equal intervals in the circumferential direction. Two adjacent baffles 142 are connected by side baffles 141 to form a hopper. In this way, the interflow liquid storage structure 14 is divided into a plurality of hoppers that can store liquid independently, forming a windmill-type structure. The interflow liquid storage structure 14 is installed on a support and is configured to be able to rotate around the support. The electrolyte is fed into the hopper through the upper liquid inlet 10. When the liquid is stored to a certain capacity, the eccentric force generated and the force generated by the electrolyte flowing down on the interflow liquid storage structure 14 will cause the interflow liquid storage structure 14 to rotate in one direction. When the liquid flow below the upper liquid inlet 10 crosses the next baffle 142, the next hopper will start to store liquid, and the electrolyte in the previous hopper will be poured into the cavity. Since the cavities for storing and discharging liquid are independent of each other at the same time, the interflow function can be realized.

[0025] In order to facilitate the liquid flow below the upper liquid inlet 10 to cross the next baffle plate 142, a folded section is provided at the end of the baffle plate 142.

[0026] To ensure that the electrolyte continues to react, the electrolyte needs to circulate, so there is a certain pressure. For this reason, an explosion-proof device (such as an explosion-proof valve) is installed on the cylinder 15. Specifically, a mounting hole 11 for installing the explosion-proof valve can be opened on the cylinder 15. When the pressure value exceeds the protection upper limit, the explosion-proof valve is a protection device.

[0027] In order to facilitate the detection of the liquid level, the electrolyte transmission device is equipped with a liquid level sensor device. The liquid level sensor device has various forms. For example, a communicating vessel-type liquid level display structure can be adopted. The liquid level sensor installation port 18 of the communicating vessel-type liquid level display structure can be opened at Figure 1-Figure 3 The upper and lower parts of the cylinder 15 are shown.

[0028] To facilitate loading and unloading, the cylinder can be set as follows Figure 1-Figure 3 In the structural form shown, both ends of the cylinder 15 are set as open ends, and are detachably connected to the upper cover 13 and the lower cover 17 respectively, and the cylinder 15, the upper cover 13 and the lower cover 17 are surrounded by the existing sealing method to form a sealed cavity.

[0029] like Figure 5-Figure 6 As shown, the liquid flow battery system of the present invention includes a main liquid storage tank 4 and at least one liquid flow battery unit 3, each liquid flow battery unit 3 is connected to the main liquid storage tank 4 through a common liquid inlet main pipe 5 and a common liquid return main pipe 6 to form a circulation pipeline, and at least one circulation pump 7 (such as a magnetic pump) is installed on the circulation pipeline.

[0030] In existing liquid flow battery systems, each liquid flow battery module usually requires an independent electrolyte supply and return path. In order to maintain the liquid flow between these modules, multiple circulation pumps are usually required to control the electrolyte circulation of each module respectively. This design not only increases energy consumption and cost, but also leads to system complexity and reliability issues. The present invention realizes the "interflow" function by introducing a new type of electrolyte transmission device. At the same time, the pressure balance of the battery stack module is maintained through the interflow device to ensure that the battery stack module obtains a uniform electrolyte supply, so that the entire system only needs a single high-power magnetic pump (such as circulation pump 7) to efficiently drive the liquid circulation of the entire system, avoiding the energy waste caused by coordinated work in the traditional multi-pump system.

[0031] Each liquid flow battery unit 3 includes at least one liquid flow battery module 2, the liquid inlet pipeline 22 of each liquid flow battery module 2 is connected to the liquid inlet main pipe 5 through a common liquid inlet branch pipe, and the liquid outlet pipeline 21 of each liquid flow battery module is connected to the liquid return main pipe 6 through a common liquid outlet branch pipe.

[0032] The electrolyte transmission device of the present invention has good adaptability and scalability, and is suitable for liquid flow battery systems of different specifications and scales. No matter how the system size changes, it is only necessary to adjust the configuration of the transmission device to meet the needs. This design makes the expansion of the system more flexible and can easily increase or decrease the number of battery modules.

[0033] The number of flow battery modules 2 in the flow battery system using the electrolyte transfer device of the present invention is 20 to 30 and only one 5.5KW magnetic pump can be used to drive the liquid circulation of the entire system. When adding modules, only the number of branches needs to be adjusted without changing the number of pumps. The power of the pump is selected according to demand.

[0034] like Figure 5-Figure 6 The liquid flow battery system shown is a battery cluster formed by 28 battery stacks, each liquid flow battery module 2 includes a battery stack 20, and every 4 liquid flow battery modules 2 form a liquid flow battery unit 3. Seven liquid flow battery units 3 are connected in parallel on the circulation pipeline, which can fully realize the charging and discharging of the system, wherein the circuit is connected in series and the liquid circuit is connected in parallel. An electrolyte transmission device 1 and a liquid inlet tank are installed on the liquid inlet pipeline 22 of each battery stack 20, and an electrolyte transmission device 1 and a liquid outlet tank are installed on the liquid outlet pipeline 21. The circulation pump 7 first fills the 28 liquid inlet tanks with liquid at the same time. At this time, the incoming liquid compresses the air in the liquid tank. When the pressure of the compressed air is greater than the flow resistance of the battery stack, the liquid flows into the battery stack, and then flows out from the battery stack to the liquid outlet tank, and then the liquid outlet tank flows into the main liquid storage tank 4, and then circulates through the circulation pump 7. In this way, the main liquid tank and the battery stack are electrically disconnected, and the use of a large pump saves power consumption.

[0035] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various specific technical features in any appropriate manner. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations. However, these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A liquid flow battery system, characterized in that: The liquid flow battery system comprises a main liquid storage tank (4) and at least one liquid flow battery unit (3), each of the liquid flow battery units (3) comprises at least one liquid flow battery module (2), and an electrolyte transmission device (1) is respectively installed on a liquid inlet pipeline (22) and a liquid outlet pipeline (21) of a battery stack (20) of the liquid flow battery module (2), and the electrolyte transmission device (1) comprises: A cylinder (15) and a cavity formed around the cylinder (15), wherein the cylinder (15) is provided with a pressure regulating port (12), an upper liquid inlet (10) and a lower liquid outlet (16); The inter-flow liquid storage structure (14) is configured to be rotatable, installed in the cavity and located below the upper liquid inlet (10) for receiving electrolyte, and the inter-flow liquid storage structure (14) has at least two hoppers arranged at an angle, and between two adjacent hoppers, when one hopper is in a receiving state, the other hopper is in a dumping state.

2. The liquid flow battery system according to claim 1, characterized in that: Each of the liquid flow battery units (3) is connected to the main liquid storage tank (4) via a liquid inlet main pipe (5) and a liquid return main pipe (6) to form a circulation pipeline, and at least one circulation pump (7) is installed on the circulation pipeline.

3. The liquid flow battery system according to claim 1, characterized in that: A support is relatively fixedly arranged in the cavity, the interflow liquid storage structure (14) is installed on the support and can rotate around the support, the interflow liquid storage structure (14) includes a hopper group, the hopper group includes two hoppers with different capacities fixedly connected at an angle of 20 to 40 degrees, the longitudinal section of the hopper is arranged in a shape of larger upper part and smaller lower part, and the support is installed in the middle upper area of ​​the hopper with larger capacity.

4. The liquid flow battery system according to claim 3, characterized in that: The longitudinal cross-section of the hoppers in the hopper group is arranged to be semicircular, semi-elliptical or trapezoidal.

5. The liquid flow battery system according to claim 1, characterized in that: A support is relatively fixedly arranged in the cavity, the interflow liquid storage structure (14) is mounted on the support and can rotate around the support, the interflow liquid storage structure (14) comprises a plurality of interflow baffles (142) extending outwards and arranged at equal intervals in the circumferential direction, and two adjacent interflow baffles (142) are connected via side baffles (141) to form the hopper.

6. The liquid flow battery system according to claim 5, characterized in that: The end of the baffle plate (142) is provided with a folded section.

7. The liquid flow battery system according to claim 1, characterized in that: An explosion-proof device is installed on the cylinder (15).

8. The liquid flow battery system according to claim 1, characterized in that: The electrolyte transport device is equipped with a liquid level sensor.

9. The liquid flow battery system according to claim 1, characterized in that: Each of the liquid flow battery units (3) comprises at least one liquid flow battery module (2), the liquid inlet pipeline (22) of each of the liquid flow battery modules (2) being connected to the liquid inlet main pipeline (5) via a liquid inlet branch pipe, and the liquid outlet pipeline (21) of each of the liquid flow battery modules being connected to the liquid return main pipeline (6) via a liquid outlet branch pipe.

10. The liquid flow battery system according to any one of claims 1 to 9, characterized in that: The number of liquid flow battery modules (2) in the liquid flow battery system is 20 to 30.

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