Automatic exhaust system of all-vanadium redox flow battery

Abstract

The invention belongs to the technical field of battery exhaust, and relates to an all-vanadium redox flow battery automatic exhaust system, which comprises an ultrasonic assembly and a conducting medium, and the degassing assembly is used for degassing the electrolyte in the all-vanadium redox flow battery stack so as to discharge bubbles in the all-vanadium redox flow battery. According to the method, an indirect ultrasonic mode is adopted, so that the ultrasonic waves can completely and uniformly act on the galvanic pile of the all-vanadium redox flow battery after penetrating through the conducting medium, and under the action of the ultrasonic waves, the electrolyte in the galvanic pile of the all-vanadium redox flow battery is cavitated or disturbed; the positive electrode electrolyte and the negative electrode electrolyte of the all-vanadium redox flow battery electric pile are respectively degassed through the degassing assembly, so that the exhaust of the all-vanadium redox flow battery is completed; the influence on the performance of the all-vanadium redox flow battery due to continuous accumulation of bubbles is avoided.

Description

Technical Field

[0001] This invention belongs to the field of battery venting technology and relates to an automatic venting system for a full vanadium redox flow battery. Background Technology

[0002] Vanadium redox flow battery (VRFB) is a redox battery that uses vanadium as the active material in a circulating liquid state. Due to its long lifespan, high safety, and flexible capacity expansion, it is mainly used for large-scale, long-term energy storage. A VRFB primarily consists of a stack (electrochemical reaction unit) and a storage tank (electrolyte storage unit), and also requires auxiliary equipment such as piping, pumps, and control systems. Hydrogen evolution and oxygen evolution reactions are a serious but often overlooked problem in VRFBs. Studies have shown that hydrogen evolution at the negative electrode can lead to an average gas bubble volume fraction exceeding 15%, and even reaching over 30% in some areas. Even with a low gas escape rate, prolonged exposure can result in a large accumulation of gas in the electrodes. Bubbles can have many adverse effects on the operation of flow batteries, specifically: 1) Bubbles block the electrodes, hindering the flow of electrolyte and causing uneven electrolyte distribution, while also increasing the voltage drop and pump work; 2) Bubbles affect the transmembrane transport of hydrogen ions, increasing the mass transfer resistance; 3) Bubbles increase the ohmic resistance, increasing the internal resistance of the battery and causing greater voltage loss.

[0003] Currently, to address the aforementioned issues, methods to reduce side reactions are commonly employed, such as acid oxidation of the electrode carbon fibers or the addition of transition metal oxides (e.g., TiO2) to the electrodes. This reduces the hydrogen evolution reaction rate and thus decreases bubble generation. However, when the vanadium redox flow battery operates for an extended period, trace amounts of bubbles will accumulate, ultimately negatively impacting the battery's performance. Summary of the Invention

[0004] The purpose of this invention is to provide an automatic venting system for vanadium redox flow batteries, which can expel the bubbles generated by the hydrogen evolution reaction of vanadium redox flow batteries, thus preventing the continuous accumulation of bubbles from affecting the performance of vanadium redox flow batteries.

[0005] To achieve the above objectives, the technical solution provided by the present invention is as follows: An automatic venting system for a vanadium redox flow battery includes: An ultrasonic component includes a bath and multiple ultrasonic transducers disposed within the bath, the multiple ultrasonic transducers being used to apply ultrasonic waves to the stack of a vanadium redox flow battery.

[0006] The conductive medium, stored in a bath, is used to contain the stack of the vanadium redox flow battery with a separator, and to conduct the ultrasonic waves to the stack of the vanadium redox flow battery, causing cavitation or disturbance of the electrolyte in the stack of the vanadium redox flow battery, thereby causing the air bubbles attached to the electrode pores to be disturbed and enter the electrolyte.

[0007] The degassing component, connected to the vanadium redox flow battery stack, is used to degas the electrolyte in the vanadium redox flow battery stack, thereby removing air bubbles from the vanadium redox flow battery.

[0008] The invention is further characterized by: The vanadium redox flow battery stack has a positive electrode outlet and a negative electrode outlet. Each of the positive and negative electrode outlets of the vanadium redox flow battery stack is equipped with a bubble monitor. Each bubble monitor is used to detect the volume fraction of bubbles in the electrolyte. When the volume fraction of bubbles in the electrolyte exceeds a preset value, multiple ultrasonic transducers are activated.

[0009] The preset value for the volume fraction of bubbles is 4% to 15%.

[0010] The degassing component includes: Two vacuum degassers are connected at their inlets to the outlets of two bubble monitors, and each vacuum degasser is used to degas the electrolyte.

[0011] The conductive medium is either water or silicone oil.

[0012] The ultrasound component also includes: The support is set inside the bath, and the vanadium redox flow battery stack is set on the support.

[0013] The bath is equipped with a temperature sensor to detect the temperature of the conductive medium inside the bath. The bath is connected to a conductive medium replenishment component. When the temperature sensor detects that the temperature of the conductive medium is not within the preset temperature range, the conductive medium replenishment component replenishes the conductive medium into the bath until the temperature of the conductive medium returns to the preset temperature.

[0014] This invention discloses an automatic venting system for a vanadium redox flow battery. Through the coordination of an ultrasonic component, a conductive medium, and a degassing component, indirect ultrasound is employed. This allows ultrasonic waves to pass through the conductive medium and act completely and uniformly on the vanadium redox flow battery stack. Under the action of the ultrasound, cavitation or disturbance occurs in the electrolyte within the vanadium redox flow battery stack. This causes tiny bubbles attached to the electrode pores to be disturbed, gradually accumulating and being discharged with the electrolyte. The degassing component then degasses the positive and negative electrolytes of the vanadium redox flow battery stack separately, completing the venting process and preventing the continuous accumulation of bubbles from affecting the performance of the vanadium redox flow battery. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0016] Figure 2 This is a schematic diagram of the overall internal structure of the bath tub in this invention.

[0017] Figure 3 This is a schematic diagram of the overall structure of the bath tub in this invention.

[0018] Figure 4 This is a schematic diagram of the internal structure of the bath tub in this invention.

[0019] Figure label: 1. Bath tub, 2. Temperature sensor, 3. Bubble monitor, 4. Partition, 5. Vacuum degasser, 6. Valve, 7. Pump, 8. Storage tank, 9. Support, 10. Bath tub inlet, 11. Bath tub outlet, 12. Negative electrode inlet, 13. Negative electrode outlet, 14. Positive electrode inlet, 15. Positive electrode outlet, 16. Ultrasonic transducer, 17. Positive electrode, 18. Negative electrode. Detailed Implementation

[0020] The technical solutions of the present invention will now be described clearly and in detail with reference to the accompanying drawings. In the description of the embodiments of the present invention, unless otherwise stated, " / " indicates "or," for example, A / B can mean A or B. "And / or" in the text is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone. Furthermore, in the description of the embodiments of the present invention, "multiple" refers to two or more. The terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature.

[0021] like Figure 1 , Figure 2 , Figure 3As shown, this invention provides an automatic venting system for a vanadium redox flow battery, including an ultrasonic component, a conductive medium, and a degassing component. The ultrasonic component includes a bath 1 and multiple ultrasonic transducers 16 disposed within the bath 1. The multiple ultrasonic transducers 16 are used to apply ultrasonic waves to the vanadium redox flow battery stack. The conductive medium is stored in the bath 1 and is used to contain the vanadium redox flow battery stack encased in a separator 4, and to conduct the ultrasonic waves to the vanadium redox flow battery stack, causing cavitation or disturbance of the electrolyte within the vanadium redox flow battery stack. This causes bubbles attached to the electrode pores to be disturbed and enter the electrolyte. The separator 4 prevents the conductive medium from entering the vanadium redox flow battery stack. The degassing component is connected to the vanadium redox flow battery stack and is used to degas the electrolyte in the vanadium redox flow battery stack, thereby removing bubbles from the vanadium redox flow battery. This invention utilizes the combination of an ultrasonic component and a degassing component, employing indirect ultrasound to ensure that ultrasonic waves pass through the conductive medium and act completely and uniformly on the vanadium redox flow battery stack. Under the action of the ultrasonic waves, the electrolyte within the vanadium redox flow battery stack undergoes cavitation or disturbance, causing tiny bubbles attached to the electrode pores to be disturbed, gradually accumulating and being discharged with the electrolyte. The degassing component then degasses the positive and negative electrolytes of the vanadium redox flow battery stack separately, completing the degassing of the vanadium redox flow battery and preventing the continuous accumulation of bubbles from affecting the performance of the vanadium redox flow battery.

[0022] The partition 4 also has insulation and good thermal conductivity, and is preferably made of engineering plastic.

[0023] like Figure 2 , Figure 4 As shown, the ultrasonic component also includes a support 9, which is disposed in the bath 1, and the stack of the vanadium redox flow battery is disposed on the support 9.

[0024] like Figure 1 As shown, the vanadium redox flow battery stack has a positive electrode outlet and a negative electrode outlet. A bubble monitor 3 is installed at the positive electrode outlet and the negative electrode outlet of the vanadium redox flow battery stack, respectively. The inlets of the two bubble monitors 3 are connected to the positive electrode outlet and the negative electrode outlet of the vanadium redox flow battery stack, respectively. Each bubble monitor 3 is used to detect the volume fraction of bubbles in the electrolyte. When the volume fraction of bubbles in the electrolyte exceeds the preset value, multiple ultrasonic transducers 16 are activated, so that the vanadium redox flow battery performs intermittent automatic degassing, that is, degassing is performed after a certain period of time.

[0025] The preset value of the bubble volume fraction is 4%~15%. Multiple ultrasonic transducers 16 emit ultrasonic waves to degas the vanadium redox flow battery, so that the bubble volume fraction is less than 4%, thus maximizing the performance of the vanadium redox flow battery.

[0026] The conductive medium is water or silicone oil, preferably water.

[0027] like Figure 1 As shown, the degassing assembly includes two vacuum degassers 5. The inlets of the two vacuum degassers 5 are connected to the outlets of two bubble monitors 3, respectively. Each vacuum degasser 5 is used to degas the electrolyte. Each vacuum degasser 5 is equipped with valves 6 at its inlet and outlet. When it is necessary to remove bubbles from the electrolyte, the valve 6 at the inlet of each vacuum degasser 5 is opened and the valve 6 at the outlet of each vacuum degasser 5 is closed. A portion of the electrolyte from the positive electrode and a portion of the electrolyte from the negative electrode of the vanadium redox flow battery stack enter the two vacuum degassers 5, respectively. After the electrolyte in each vacuum degasser 5 reaches a set value, the valve 6 at the inlet of each vacuum degasser 5 is closed, and each vacuum degasser 5 is evacuated. The gas pressure above the electrolyte surface decreases, the gas solubility decreases, and the gas escapes from the electrolyte, completing the degassing of the electrolyte.

[0028] like Figure 1 As shown, the outlet of each vacuum degasser 5 is connected to a storage tank 8 via a pump 7. After the electrolyte is degassed in each vacuum degasser 5, the valve 6 at the outlet of the vacuum degasser 5 is opened, the pump 7 is started, and the electrolyte is sent into the storage tank 8 to continue to participate in the circulation. According to the water balance law, this part of the gas-free electrolyte injected back into the system has a strong adsorption capacity. All gases in the system, whether free or dissolved, will be absorbed by it. When water re-enters the degasser, the gas is removed again. This cycle repeats continuously, eventually discharging most of the gas in the entire vanadium redox flow battery, so that the system operates in a state of almost no gas.

[0029] like Figure 1 As shown, a connecting pipe is provided between the outlet of each bubble monitor 3 and the inlet of the pump 7. A first solenoid valve is provided on the connecting pipe to facilitate normal circulation of the electrolyte when degassing is not performed.

[0030] like Figure 3 , Figure 4 As shown, the vanadium redox flow battery stack has a negative electrode inlet 12, a negative electrode outlet 13, a positive electrode inlet 14, a positive electrode outlet 15, a positive electrode 17, and a negative electrode 18. The negative electrode outlet 13 and the positive electrode outlet 15 of the vanadium redox flow battery stack are respectively connected to the inlets of two bubble monitors 3.

[0031] like Figure 1 , Figure 3 As shown, a temperature sensor 2 is installed inside the bath tub 1. The temperature sensor 2 is used to detect the temperature value of the conductive medium inside the bath tub 1. The bath tub 1 is connected to a conductive medium replenishment component. When the temperature sensor 2 detects that the temperature value of the conductive medium is not within the preset temperature, the conductive medium replenishment component replenishes the conductive medium into the bath tub 1 until the temperature value of the conductive medium returns to the preset temperature.

[0032] The conductive medium replenishment component includes a first water pump and a second water pump. A bath inlet 10 and a bath outlet 11 are respectively provided on both sides of the bath tank 1. A second solenoid valve is provided on the bath inlet 10 and the bath outlet 11 respectively. The inlet of the first water pump is connected to a first medium storage tank. The outlet of the first water pump is connected to the bath inlet 10. The inlet of the second water pump is connected to the bath outlet 11. The inlet of the second water pump is connected to a second medium storage tank.

[0033] The preset temperature of the conductive medium is 20℃~25℃.

[0034] During the summer, the ambient temperature is high, and the vanadium redox flow battery stack itself releases heat, causing the water temperature in bath 1 to rise. The water temperature in bath 1 is set to 20℃~25℃. When the water temperature in bath 1 rises to 25℃, the second solenoid valves of bath inlet 10 and bath outlet 11 open, sending cold water into bath 1 and extracting hot water from bath 1. When the water temperature in the ultrasonic bath drops to 20℃, the second solenoid valves of bath inlet 10 and bath outlet 11 close.

[0035] When it is winter, the ambient temperature is low. The heat released by the vanadium redox flow battery stack and multiple ultrasonic transducers 16 during operation will be less than the heat released by the water in the ultrasonic bath 1 to the environment. The water temperature in the ultrasonic bath will decrease. The water temperature in the ultrasonic bath 1 is set to 20℃~25℃. When the water temperature in the ultrasonic bath drops to 20℃, the second solenoid valves of the bath inlet 10 and the bath outlet 11 are opened to send hot water into the bath 1 and extract the cold water in the bath 1. When the water temperature in the ultrasonic bath rises to 25℃, the second solenoid valves of the bath inlet 10 and the bath outlet 11 are closed.

[0036] Working Principle: When one or two bubble monitors 3 detect that the volume fraction of bubbles in the corresponding electrolyte exceeds a specified value, multiple ultrasonic transducers 16 are activated. These transducers emit ultrasonic waves towards the vanadium redox flow battery stack. The ultrasonic waves pass through the water and act on the stack, causing cavitation or disturbance in the electrolyte. This disturbs the tiny bubbles attached to the electrode pores, causing them to gradually aggregate and be discharged with the electrolyte. Simultaneously, the inlet valve 6 of each vacuum degasser 5 is opened, and the outlet valve 6 of each vacuum degasser 5 is closed. A portion of the electrolyte from the positive electrode and a portion from the negative electrode of the vanadium redox flow battery stack enters the two vacuum degassers 5 respectively. Once the electrolyte level in each vacuum degasser 5 reaches the set value, the inlet valve 6 of each vacuum degasser 5 is closed, and each vacuum degasser 5 is evacuated. The pressure above the electrolyte surface decreases, reducing gas solubility and causing gas to escape from the electrolyte, thus completing the degassing process. After the electrolyte is degassed in each vacuum degasser 5, the valve 6 at the outlet of the vacuum degasser 5 is opened, the pump 7 is started, and the electrolyte is sent into the storage tank 8 to continue to participate in the circulation.

[0037] It is understood that this invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of this invention. Furthermore, under the teachings of this invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of this invention. Therefore, this invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this invention are within the protection scope of this invention.

Claims

1. An automatic venting system for a vanadium redox flow battery, characterized in that, include: An ultrasonic assembly includes a bath (1) and a plurality of ultrasonic transducers (16) disposed within the bath (1), the plurality of ultrasonic transducers (16) being used to apply ultrasonic waves to the stack of a vanadium redox flow battery. The conductive medium is stored in the bath (1). The conductive medium is used to contain the stack of the vanadium redox flow battery wrapped with the separator (4) and conduct the ultrasonic waves to the stack of the vanadium redox flow battery, so that the electrolyte in the stack of the vanadium redox flow battery will be cavitated or disturbed, thereby causing the bubbles attached to the electrode pores to be disturbed and enter the electrolyte. The degassing component, connected to the vanadium redox flow battery stack, is used to degas the electrolyte in the vanadium redox flow battery stack, thereby removing air bubbles from the vanadium redox flow battery.

2. The automatic venting system for a vanadium redox flow battery according to claim 1, characterized in that, The vanadium redox flow battery stack has a positive electrode outlet and a negative electrode outlet. The positive electrode outlet and the negative electrode outlet of the vanadium redox flow battery stack are respectively equipped with a bubble monitor (3). Each bubble monitor (3) is used to detect the volume fraction of bubbles in the electrolyte. When the volume fraction of bubbles in the electrolyte exceeds a preset value, multiple ultrasonic transducers (16) are activated.

3. The automatic venting system for a vanadium redox flow battery according to claim 2, characterized in that, The preset value for the volume fraction of the bubbles is 4% to 15%.

4. The automatic venting system for a vanadium redox flow battery according to claim 2, characterized in that, The degassing component includes: Two vacuum degassers (5) are connected at their inlets to the outlets of two bubble monitors (3), and each vacuum degasser (5) is used to degas the electrolyte.

5. The automatic venting system for a vanadium redox flow battery according to claim 1, characterized in that, The conductive medium is water or silicone oil.

6. The automatic venting system for a vanadium redox flow battery according to claim 1, characterized in that, The ultrasound component also includes: A support (9) is set inside a bath (1), and the stack of the vanadium redox flow battery is set on the support (9).

7. The automatic venting system for a vanadium redox flow battery according to claim 1, characterized in that, A temperature sensor (2) is installed inside the bath (1). The temperature sensor (2) is used to detect the temperature value of the conductive medium inside the bath (1). The bath (1) is connected to a conductive medium replenishment component. When the temperature sensor (2) detects that the temperature value of the conductive medium is not within the preset temperature, the conductive medium replenishment component replenishes the conductive medium into the bath (1) until the temperature value of the conductive medium is restored to the preset temperature.

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