Liquid leakage detection device and detection method for all-vanadium redox flow battery system

Abstract

The invention discloses a liquid leakage detection device for an all-vanadium redox flow battery system. The all-vanadium redox flow battery system comprises a battery management system and an all-vanadium redox flow battery, the liquid leakage detection device comprises a plurality of liquid leakage detection belts, a liquid leakage probe and a liquid leakage detection circuit; the liquid leakage detection belt is laid outside a to-be-monitored assembly of the all-vanadium redox flow battery in a crossed manner; the liquid leakage probe is arranged at the intersection of the liquid leakage detection belts, and the crossed liquid leakage detection belts are electrically connected through the liquid leakage probe; the liquid leakage detection circuit comprises an ADC (Analog to Digital Converter) detection channel for processing a liquid leakage probe signal; and an electric loop is formed among the battery management system, the liquid leakage detection belt, the liquid leakage probe and the liquid leakage detection circuit. The liquid leakage detection area can be greatly increased, the liquid leakage point can be accurately positioned, the operation reliability of a battery system is improved, and large-scale application of the all-vanadium redox flow battery is promoted.

Description

Technical Field

[0001] The present application relates to a liquid leakage detection device and a detection method for a vanadium redox flow battery system, belonging to the technical field of electrochemical energy storage. Background Art

[0002] The adjustment of China's energy structure has been accelerating, and the gradual replacement of traditional fossil energy by new energy will be an inevitable trend in history. China has a vast territory and is rich in solar and wind energy resources. However, these natural energies have characteristics such as intermittency and volatility, and it will encounter great difficulties to directly connect to the power grid and must be smoothed first. At the same time, there are often mismatches between power supply and demand in terms of time and space, showing phenomena such as peak-valley bands and regional imbalance. An important way to solve the above problems is energy storage technology. In particular, electrochemical energy storage also has the advantages of high efficiency, fast response speed, and being unrestricted by geographical environment, and is suitable for the smoothing of wind and solar power generation on the supply side and also for the power management on the demand side. Compared with other electrochemical energy storage technologies, the vanadium redox flow battery has the characteristics of intrinsic safety, extremely long cycle life, and decoupling of capacity and power, and is particularly suitable for large-scale energy storage power stations.

[0003] In a vanadium redox flow battery system, the electrolytes are stored in the positive and negative electrolyte storage tanks respectively. The positive and negative electrolytes flow back to the storage tanks through the electrolyte circulation pump, the stack, and the pipelines. Since the normal operation of the battery system requires the electrolytes to circulate continuously in the storage tanks, the circulation pump, the stack, and the pipelines, it is inevitable that liquid leakage will occur in the battery system after a long time.

[0004] How to quickly and effectively detect the liquid leakage of the system and locate the liquid leakage point is particularly crucial. At present, the detection methods for the liquid leakage point of the battery system in the industry are either through the change of the pipeline pressure value or through placing several probes to detect the liquid leakage of the system. The above detection methods have certain effects, but have great limitations. There are many influencing factors for the change of the pipeline pressure value, and the pressure value will also change if the pressure sensor is damaged, resulting in false alarms of the battery system and reducing the availability of the battery system. Placing several liquid leakage probes can only detect the liquid leakage at the probe points. If liquid leakage occurs in other places, the battery management system cannot detect it quickly. Summary of the Invention

[0005] According to one aspect of the present application, a liquid leakage detection device for a vanadium redox flow battery system is provided. The matrix-type liquid leakage detection circuit is adopted to replace the traditional point-type detection, solving the problems of small detection area, inability to quickly detect the location of the liquid leakage point, and false alarms of the battery system in the existing liquid leakage detection technology.

[0006] The present application adopts the following technical solutions:

[0007] A liquid leakage detection device for a vanadium redox flow battery system, the vanadium redox flow battery system includes a battery management system and a vanadium redox flow battery;

[0008] The liquid leakage detection device includes a plurality of liquid leakage detection tapes, liquid leakage probes, and a liquid leakage detection circuit;

[0009] The liquid leakage detection tapes are cross-laid outside the components to be monitored of the all-vanadium redox flow battery;

[0010] The liquid leakage probes are arranged at the intersections of the liquid leakage detection tapes, and the intersecting liquid leakage detection tapes are electrically connected by the liquid leakage probes;

[0011] The liquid leakage detection circuit includes an ADC detection channel for processing the signals of the liquid leakage probes;

[0012] An electrical circuit is formed among the battery management system, the liquid leakage detection tapes, the liquid leakage probes, and the liquid leakage detection circuit.

[0013] Optionally, the components to be monitored are selected from at least one of a positive electrode liquid storage tank, a negative electrode liquid storage tank, an electrolytic cell stack, and a pipeline.

[0014] Optionally, the liquid leakage detection device includes a liquid leakage detection tape grid formed by cross-distribution of at least 2 horizontal liquid leakage detection tapes and at least 2 vertical liquid leakage detection tapes.

[0015] Optionally, the liquid leakage detection device includes at least 1 liquid leakage detection tape grid.

[0016] Each horizontal liquid leakage detection tape and vertical liquid leakage detection tape are not directly connected at the intersection, but are connected by a liquid leakage probe, and all the liquid leakage detection probes are pre-defined with numbers.

[0017] Optionally, the liquid leakage detection circuit includes end electrode plates of the liquid leakage probes and a microcontroller unit;

[0018] The microcontroller unit includes an ADC detection channel, a UART, and a GPIO;

[0019] The voltage of the end electrode plates of the liquid leakage probes is transmitted to the ADC detection channel after passing through a resettable fuse and a resistor for current limiting.

[0020] In this application, the battery management system collects the operating parameters of the battery system, such as battery voltage, battery current, pipeline pressure, pipeline flow rate and other parameters. When the parameters exceed the limit values, the battery system gives a protection alarm. When liquid leakage occurs in the electrolytic cell stack, pipeline system, and electrolyte storage tank, the battery system gives an alarm for protection, stops the operation of the variable-frequency pump, and closes the system electric valve. When there is no liquid leakage in the system, all the liquid leakage probes are in an open circuit state, and the ADC signal input to the main controller of the battery management system is at a high level; when liquid leakage occurs at a certain place, the liquid leakage probe at that place is in a short circuit state, and the ADC signal input to the main controller of the battery management system is at a low level.

[0021] According to another aspect of the present application, a method for detecting liquid leakage in a vanadium redox flow battery system is provided, which is characterized by including the following steps:

[0022] Use the liquid leakage detection device for the vanadium redox flow battery system according to any one of claims 1 to 4 to perform liquid leakage detection. The liquid leakage probe signal is input to the ADC detection channel, and the battery management system detects the ADC signal, reads the ADC value, and compares it with the alarm threshold set in the battery management system to determine whether there is liquid leakage;

[0023] When there is no liquid leakage in the vanadium redox flow battery system, all the liquid leakage probes are in an open state, and the ADC signals are all high-level signals;

[0024] When there is liquid leakage in the vanadium redox flow battery system, the liquid leakage probe in contact with the liquid near the liquid leakage point becomes a short-circuit state, the ADC signal appears as a low-level signal, and the battery management system controls the circulating pump to stop running, automatically closes the system electric valve, and issues a liquid leakage alarm.

[0025] Optionally, the method for detecting liquid leakage in the vanadium redox flow battery system includes using a liquid leakage detection belt with a grid;

[0026] The liquid leakage detection belt with a grid includes n + 1 horizontal liquid leakage detection belts marked as row lines X0 to X n and n + 1 vertical liquid leakage detection belts marked as column lines Y0 to Y n .

[0027] Optionally, the method for detecting liquid leakage in the vanadium redox flow battery system further includes the following positioning steps:

[0028] S1. When there is liquid leakage in the vanadium redox flow battery system, set all the ADC signals of the column lines Y0 to Y n to low level, and detect the ADC signals of the row lines X0 to X n through the battery management system to locate the row line X m that becomes a low-level signal;

[0029] S2. Reset the row line X m with the low-level signal to high level, set the column line Y m to low level, and set the remaining column lines to high level. If the ADC signal of the row line X m becomes a low-level signal when detected by the battery management system, the liquid leakage point is located near the liquid leakage probe at the intersection of the row line Xm and the column line Y m ;

[0030] S3. Repeat step S2 to obtain the positioning coordinates (X m , Y m ) of all the liquid leakage points, where 0 ≤ m ≤ n.

[0031] Optionally, the liquid leakage detection belt with a grid is arranged at the bottoms of the positive electrode liquid storage tank and the negative electrode liquid storage tank; and / or,

[0032] the liquid leakage detection belt with a grid is arranged directly below the bracket of the stack; and / or,

[0033] the liquid leakage detection belt with a grid is wound around the outside of the pipeline.

[0034] In the prior art, the liquid leakage points of the all-vanadium redox flow battery generally exist in three places, namely, the bottoms of the positive and negative electrode liquid storage tanks, the lower part of the stack, and the pipeline system. Therefore, the liquid leakage monitoring of the battery system is mainly arranged at these three positions.

[0035] Optionally, the liquid leakage detection method of the all-vanadium redox flow battery system further includes alarm threshold correction;

[0036] The battery management system detects the humidity of the environment where the all-vanadium redox flow battery is located, and uses the high-level ADC voltage value corresponding to this humidity as the alarm threshold.

[0037] When the battery system is placed in a place with high humidity, the resistance value between the liquid leakage probes will decrease. At this time, the ADC voltage value detected by the battery management system will change. Therefore, the alarm condition can be determined by adjusting the liquid leakage alarm threshold, so as to avoid false alarms caused by high air humidity.

[0038] For the liquid leakage detection method of the all-vanadium redox flow battery system provided in this application, the battery management system can detect the signals of multiple liquid leakage probes placed in a matrix crosswise, discover the liquid leakage signal in the first time, stop the frequency converter, send out a liquid leakage signal alarm, and at the same time, according to the liquid leakage signal, accurately locate the position of the liquid leakage point. The alarm information and the liquid leakage position are displayed on the local human-machine interface, and can also be remotely transmitted to the third-party monitoring system through communication for the convenience of users to query.

[0039] The liquid leakage detection accuracy of the liquid leakage detection method of the all-vanadium redox flow battery system provided in this application can be achieved by adjusting the distance between the horizontal liquid leakage detection belt and the vertical liquid leakage detection belt. When the distance between the horizontal liquid leakage detection belt and the vertical liquid leakage detection belt is smaller, the liquid leakage detection accuracy is higher.

[0040] The beneficial effects that can be produced by this application include:

[0041] The liquid leakage detection device for the all-vanadium redox flow battery system provided in this application adopts a matrix liquid leakage detection circuit, replaces the traditional point detection, can greatly increase the area of liquid leakage detection, accurately locate the liquid leakage point, improve the reliability of the battery system operation, and is conducive to promoting the large-scale application of the all-vanadium redox flow battery. Description of the Drawings

[0042] Figure 1Schematic diagram of the liquid leakage detection circuit in this application.

[0043] Figure 2 Schematic diagram of the principle of matrix liquid leakage detection adopted in this application.

[0044] Figure 3 Schematic diagram of the principle of matrix liquid leakage detection adopted in Embodiment 1 of this application.

[0045] Figure 4 Schematic diagram of the detection process of the liquid leakage detection method for the all-vanadium redox flow battery system of this application. Detailed implementation manners

[0046] The following describes this application in detail with reference to the embodiments, but this application is not limited to these embodiments.

[0047] Unless otherwise specified, the raw materials in the embodiments of this application are all purchased through commercial channels.

[0048] Unless otherwise specified, the test methods are all conventional methods, and the instrument settings are all the settings recommended by the manufacturers.

[0049] According to an implementation manner of this application,

[0050] The liquid leakage detection belts are cross-laid outside the components to be monitored of the all-vanadium redox flow battery to form a liquid leakage detection belt grid. As Figure 2 shown, the liquid leakage detection belt grid includes n + 1 horizontal liquid leakage detection belts marked as row lines X0 to X n and n + 1 vertical liquid leakage detection belts marked as column lines Y0 to Y n . Each row line is connected to the liquid leakage detection circuit for signal processing. The liquid leakage probes are arranged at the intersections of the liquid leakage detection belts. The intersecting liquid leakage detection belts are electrically connected by the liquid leakage probes. They are all in an open circuit state before detection. The liquid leakage detection circuit is as Figure 1 shown. The voltage of the end electrode plate of the liquid leakage probe is sent to the ADC detection channel in the microcontroller unit after passing through the resettable fuse F1 for current limiting and the resistor R2. The level signal is output through the GPIO in the microcontroller unit, and data communication is carried out with the battery management system through UART. When the liquid leakage probe detects liquid, the resistance between the two ends of the electrode plate of the liquid leakage probe will decrease, and the voltage of the left probe end of the liquid leakage probe will become lower. The voltage passes through the resettable fuse F1 and is sent to the ADC detection channel of the controller after current limiting by the R2 resistor. The controller reads the ADC value on the channel and judges whether there is liquid leakage by comparing it with the set liquid leakage threshold.

[0051] The detection process of the liquid leakage detection method for the all-vanadium redox flow battery system is as Figure 4As shown, the battery management system controller inspects the status of the liquid leakage probe, specifically as follows: Detect the horizontal and vertical liquid leakage detection bands respectively. If the horizontal liquid leakage detection band X m (0 ≤ m ≤ n) are all at high level, then no liquid leakage occurs. If a low level is detected, locate the horizontal liquid leakage detection band X where the liquid leakage occurs m ' for positioning detection, where (0 ≤ m ≤ n). Set the liquid leakage detection band X m ' to high level, set Y0 to low level, and set other vertical liquid leakage detection bands to high level. When X m ' becomes low level, then there is liquid leakage near the intersection of X m ' and Y0. If X m ' remains at high level, then set Y1 to low level and set other vertical liquid leakage detection bands to high level. When X m ' becomes low level, then there is liquid leakage near the intersection of X m ' and Y1. If X m ' remains at high level, then repeat the above steps to set Y2 to Y n to low level respectively to detect whether there is liquid leakage at the intersections of Y2 to Y n and X m '. According to the above method, check and detect all liquid leakage points. When the battery management system detects liquid leakage, stop the operation of the circulation pump, automatically close the system electric valve, and issue an audible and visual alarm for liquid leakage to prompt the user to handle it.

[0052] Embodiment 1

[0053] The all-vanadium redox flow battery system is a set of 250kW / 1MWh all-vanadium redox flow battery system. The positive and negative liquid storage tanks are placed independently, and the stack, pipelines, heat exchange, battery management system, and various sensors are placed in a 20-foot container. As Figure 3 shown, the layout of the liquid leakage detection device is as follows: At the bottoms of the positive and negative liquid storage tanks, lay 5 horizontal (X n ) and 5 vertical (Y n ) liquid leakage detection bands respectively. The distance between every two horizontal liquid leakage detection bands (X0 and X1, and so on) is 0.5 meters, and the distance between two vertical liquid leakage detection bands (Y0 and Y1, and so on) is also 0.5 meters. Place liquid leakage detection probes at the intersection points of the horizontal and vertical layouts. Each liquid leakage probe is set with a unique label, and each horizontal liquid leakage detection band is connected to a liquid leakage detection circuit for signal processing.

[0054] The battery management system controller inspects the status of the liquid leakage probes numbered 1 - 25 as Figure 3 shown, specifically as follows: Detect the horizontal and vertical liquid leakage detection bands respectively. For example, when locating the X1 horizontal liquid leakage detection band for positioning detection, then X m'Set it to X1''. Set the liquid leakage detection tape X1' to high level, set Y0 to low level, and set Y1 - Y4 to high level. When X1' becomes low level, there is liquid leakage near the intersection of X1' and Y0. If X1' remains high level, set Y1 to low level, and set Y0, Y2 - Y4 to high level. If X m 'becomes low level, there is liquid leakage near the intersection of X1' and Y1. If X1' remains high level, repeat the above steps to set Y2, Y3, and Y4 to low level in sequence to detect whether there is liquid leakage at the intersections of Y2, Y3, Y4 and X1' respectively.

[0055] When the battery management system detects liquid leakage, stop the operation of the circulation pump, automatically close the system electric valve, and give an audible and visual alarm for liquid leakage to prompt the user to handle it.

[0056] The above are only several embodiments of the present application, and do not impose any form of limitation on the present application. Although the present application is disclosed above with preferred embodiments, it is not intended to limit the present application. Any person skilled in the art, without departing from the scope of the technical solution of the present application, makes some changes or modifications using the technical content disclosed above, which are all equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A liquid leakage detection device for a vanadium redox flow battery system, characterized in that, The all-vanadium redox flow battery system includes a battery management system and an all-vanadium redox flow battery; The liquid leakage detection device includes a plurality of liquid leakage detection tapes, liquid leakage probes, and a liquid leakage detection circuit; The liquid leakage detection tapes are cross-laid outside the components to be monitored of the all-vanadium redox flow battery; The liquid leakage probes are arranged at the intersections of the liquid leakage detection tapes, and the intersecting liquid leakage detection tapes are electrically connected by the liquid leakage probes; The liquid leakage detection circuit includes an ADC detection channel for processing the signals of the liquid leakage probes; An electrical circuit is formed among the battery management system, the liquid leakage detection tapes, the liquid leakage probes, and the liquid leakage detection circuit.

2. The liquid leakage device for a vanadium redox flow battery system according to claim 1, characterized in that, The components to be monitored are selected from at least one of a positive electrode liquid storage tank, a negative electrode liquid storage tank, an electrolytic stack, and a pipeline.

3. The liquid leakage device for a vanadium redox flow battery system according to claim 1, characterized in that, The liquid leakage detection device includes a liquid leakage detection tape grid formed by cross-distribution of at least two transverse liquid leakage detection tapes and at least two longitudinal liquid leakage detection tapes.

4. The liquid leakage device for a vanadium redox flow battery system according to claim 3, characterized in that, The liquid leakage detection device includes at least one liquid leakage detection tape grid.

5. The liquid leakage device for a vanadium redox flow battery system according to claim 1, characterized in that, The liquid leakage detection circuit includes the end electrode plates of the liquid leakage probes and a microcontroller unit; The microcontroller unit includes an ADC detection channel, a UART, and a GPIO; The voltage of the end electrode plates of the liquid leakage probes is transmitted to the ADC detection channel after passing through a resettable fuse and a resistor for current limiting.

6. A liquid leakage detection method for a vanadium redox flow battery system, characterized in that, It includes the following steps: Use the liquid leakage detection device for the all-vanadium redox flow battery system according to any one of claims 1 to 4 to perform liquid leakage detection. The signals of the liquid leakage probes are input into the ADC detection channel. The battery management system detects the ADC signal, reads the ADC value, and compares it with the alarm threshold set in the battery management system to determine whether there is liquid leakage; When there is no liquid leakage in the all-vanadium redox flow battery system, all the liquid leakage probes are in an open state, and the ADC signals are all high-level signals; When there is liquid leakage in the all-vanadium redox flow battery system, the liquid leakage probes in contact with the liquid near the liquid leakage point become short-circuited states, low-level signals appear in the ADC signals, the battery management system controls the circulating pump to stop running, automatically closes the system electric valve, and issues a liquid leakage alarm.

7. The liquid leakage detection method for a vanadium redox flow battery system according to claim 6, characterized in that, The liquid leakage detection method for the all-vanadium redox flow battery system includes using a liquid leakage detection tape grid; The leakage detection belt grid includes n + 1 horizontal leakage detection belts marked as row lines X0 to X n and n + 1 vertical leakage detection belts marked as column lines Y0 to Y n .

8. The liquid leakage detection method for a vanadium redox flow battery system according to claim 7, characterized in that, The liquid leakage detection method for the all-vanadium redox flow battery system further includes the following positioning steps: S1. When leakage occurs in the all-vanadium redox flow battery system, set all the ADC signals of column lines Y0 to Y n to low level, and detect the ADC signals of row lines X0 to X n through the battery management system to locate the row line X m that becomes a low-level signal; S2. Reset the row line X of the low-level signal to high level, set the column line Y to low level, and set the remaining column lines to high level. Detect the ADC signal of the row line X through the battery management system. If it becomes a low-level signal, the leakage point is located near the leakage probe at the intersection of the row line Xm and the column line Y; m Reset the row line X of the low-level signal to high level, set the column line Y to low level, and set the remaining column lines to high level. Detect the ADC signal of the row line X through the battery management system. If it becomes a low-level signal, the leakage point is located near the leakage probe at the intersection of the row line Xm and the column line Y; m Reset the row line X of the low-level signal to high level, set the column line Y to low level, and set the remaining column lines to high level. Detect the ADC signal of the row line X through the battery management system. If it becomes a low-level signal, the leakage point is located near the leakage probe at the intersection of the row line Xm and the column line Y; m Reset the row line X of the low-level signal to high level, set the column line Y to low level, and set the remaining column lines to high level. Detect the ADC signal of the row line X through the battery management system. If it becomes a low-level signal, the leakage point is located near the leakage probe at the intersection of the row line Xm and the column line Y; m Reset the row line X of the low-level signal to high level, set the column line Y to low level, and set the remaining column lines to high level. Detect the ADC signal of the row line X through the battery management system. If it becomes a low-level signal, the leakage point is located near the leakage probe at the intersection of the row line Xm and the column line Y; S3. Repeat step S2 to obtain the positioning coordinates (X m , Y m ) of all liquid leakage points, where 0 ≤ m ≤ n.

9. The liquid leakage detection method for a vanadium redox flow battery system according to claim 7, characterized in that, The liquid leakage detection tape grid is arranged at the bottom of the positive electrode liquid storage tank and the negative electrode liquid storage tank; and / or, The liquid leakage detection tape grid is arranged directly below the bracket of the electrolytic stack; and / or, The liquid leakage detection tape grid is wound around the outside of the pipeline.

10. The liquid leakage detection method for a vanadium redox flow battery system according to claim 6, characterized in that, The liquid leakage detection method for the all-vanadium redox flow battery system further includes alarm threshold correction; The battery management system detects the ambient humidity of the all-vanadium redox flow battery and uses the high-level ADC voltage value corresponding to this humidity as the alarm threshold.

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