All-vanadium redox flow battery pipeline constant pressure control system and method

Abstract

The invention relates to the technical field of electrochemical energy storage, in particular to an all-vanadium redox flow battery pipeline constant pressure control system and method, and the system comprises a battery management system and a constant pressure control system connected with the battery management system; the battery management system is used for receiving a collected pressure signal on an all-vanadium redox flow battery pipeline, calculating the pressure signal, comparing the calculated pressure signal with a given pressure parameter, obtaining a frequency regulation parameter, and sending the frequency regulation parameter to the constant pressure control system; meanwhile, the battery management system monitors the acquired running parameters of the all-vanadium redox flow battery; and the constant pressure control system is used for receiving the frequency adjustment parameters and adjusting positive and negative electrode pressure values in positive and negative electrode pipelines of the all-vanadium redox flow battery in a PID control mode, so that the positive and negative electrode pressure values are kept at a given pressure value. According to the invention, the pipeline pressure of the battery system is almost kept unchanged, the performance of the battery is optimized, and the utilization rate of the electrolyte of the battery system is greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electrochemical energy storage technology, in particular to a constant pressure control system and method for vanadium flow battery pipeline. BACKGROUND

[0002] With the acceleration of energy structure adjustment in China, the gradual replacement of new energy by traditional fossil energy will be a historical necessity. China has a vast territory and abundant solar and wind energy resources, but these natural energy sources have characteristics such as intermittency and volatility, and direct integration into the power grid will encounter great difficulties, so they must be smoothed first. At the same time, power supply and demand often mismatch in time and space, showing phenomena such as peak-valley wave bands and regional imbalance. An important way to solve the above problems is energy storage technology, especially electrochemical energy storage, which also has the advantages of high efficiency, fast response speed, no geographical environment restrictions, and is suitable for demand-side power management. Compared with other electrochemical energy storage technologies, vanadium flow batteries have the characteristics of intrinsic safety, ultra-long cycle life, decoupling of capacity and power, high residual value, and abundant vanadium resources, which are particularly suitable for large-scale energy storage power stations.

[0003] In a vanadium flow battery system, electrolyte is stored in positive and negative electrolyte tanks. The positive and negative electrolytes flow back to the electrolyte tanks through electrolyte circulating pumps, electrolyte stacks, and pipelines. Since the battery system needs to circulate electrolyte in the electrolyte tanks, circulating pumps, electrolyte stacks, and pipelines, the circulating pumps use a fixed frequency control method. As the number of charge and discharge cycles increases, the electrolyte temperature changes, the number of moles of various ions in the electrolyte changes, and the electrolyte concentration changes, causing the same motor set frequency and a large change in pipeline pressure. Therefore, after the battery system has been running for a period of time, the pipeline pressure decreases, affecting the charge and discharge performance of the battery system, and causing the capacity of the battery system to decay.

[0004] How to avoid the above problems for stable and reliable operation of the battery system is particularly critical. The current industry conventional treatment method is to manually adjust the electrode frequency set value when the positive and negative pipeline pressure decreases to ensure that the battery system pipeline pressure value remains unchanged. This method can improve the above problems, but it requires human intervention and increases the maintenance cost of the system. SUMMARY

[0005] The present application aims to provide a constant pressure control system and method for vanadium flow battery pipeline, which uses a PID algorithm to set the system pipeline pressure value as the target value. When the system pipeline pressure increases or decreases, the frequency set value of the frequency converter is automatically adjusted to keep the pipeline pressure value within a certain range. This method can ensure that the pipeline pressure of the battery system remains almost unchanged, optimizing the performance of the battery and greatly improving the utilization rate of the electrolyte of the battery system.

[0006] The technical scheme adopted by the present application to achieve the above-mentioned purpose is as follows: a constant pressure control system for a vanadium redox flow battery pipeline, comprising: a battery management system and a constant pressure control system connected thereto.

[0007] The battery management system is used for receiving the pressure signals collected on the vanadium redox flow battery pipeline, performing calculation and comparison with the given pressure parameters, obtaining the frequency adjustment parameters and sending them to the constant pressure control system; at the same time, the battery management system monitors the vanadium redox flow battery operation parameters collected by it.

[0008] The constant pressure control system is used for receiving the frequency adjustment parameters and adjusting the positive and negative electrode pressure values in the positive and negative electrode pipelines of the vanadium redox flow battery through the PID control mode, so that the positive and negative electrode pressure values are kept at the given pressure values.

[0009] The battery management system comprises a PLC, an IO module, a human-computer interaction module, a communication module and a data acquisition and storage module.

[0010] The data acquisition and storage module is connected with the PLC through the IO module and is used for sending the collected various vanadium redox flow battery operation parameters to the PLC through the IO module.

[0011] The human-computer interaction module is connected with the PLC and is used for interacting with the PLC to control the operation of the battery management system, and at the same time, to set the alarm values of the various vanadium redox flow battery operation parameters and the given pressure parameters of the vanadium redox flow battery.

[0012] The IO module has a plurality of modules, and the number of the modules corresponds to the interface settings of the data acquisition and storage module for collecting the vanadium redox flow battery operation parameters.

[0013] The communication module is an Ethernet interface, a wireless WIFI module or a 4G network module, and is connected with the PLC and is used for data interaction between the PLC and the third-party terminal monitoring equipment.

[0014] The PLC is used for receiving the various vanadium redox flow battery operation parameters collected by the data acquisition and storage module, monitoring the vanadium redox flow battery operation parameters according to the alarm values of the various vanadium redox flow battery operation parameters, receiving the standard signals of the real-time vanadium redox flow battery pressure values, comparing them with the given pressure parameters, obtaining the frequency adjustment parameters and sending them to the constant pressure control system.

[0015] The vanadium redox flow battery operation parameters include battery voltage, battery charge and discharge current, pipeline system pressure, flow, electrolyte temperature, positive and negative electrode liquid level and single cell voltage of the stack.

[0016] The data acquisition storage module comprises positive and negative electrode flow sensors, positive and negative electrode temperature sensors, voltage sensors, current sensors, liquid level sensors and pressure sensors connected with the IO module.

[0017] The pressure sensor is installed on the vanadium redox flow battery pipeline and is used for converting the collected pressure signal into a standard signal of 4-20 mA through an analog input module and sending the signal to the PLC of the battery management system for PID control.

[0018] The positive and negative electrode flow sensors are respectively arranged on the positive and negative electrode pipelines of the vanadium redox flow battery and are used for detecting the flow of the positive and negative electrode pipelines of the vanadium redox flow battery.

[0019] The positive and negative electrode temperature sensors are respectively arranged on the positive and negative electrode pipelines of the vanadium redox flow battery and are used for detecting the temperature of the positive and negative electrode pipelines of the vanadium redox flow battery.

[0020] The voltage sensor and the current sensor are respectively used for detecting the voltage value and the current value of the vanadium redox flow battery.

[0021] The liquid level sensor is arranged in the positive and negative electrode storage tanks of the vanadium redox flow battery and is used for detecting the liquid level value of the positive and negative electrode storage tanks.

[0022] The constant pressure control system comprises a pressure sensor, a frequency converter and an electrolyte pump.

[0023] The frequency converter is a fan water pump type frequency converter connected with the PLC and the electrolyte pump, is used for receiving the frequency adjustment parameters sent by the battery management system, and controls the rotating speed of the electrolyte pump, so that the pressure in the vanadium redox flow battery is kept at a given pressure value.

[0024] The electrolyte pump is provided with two electrolyte pumps respectively arranged on the positive and negative electrode pipelines of the vanadium redox flow battery and is used for detecting the pressure value on the positive and negative electrode pipelines respectively.

[0025] The two electrolyte pumps are respectively connected with corresponding frequency converters and are independently controlled through the corresponding frequency converters.

[0026] Further comprising an insulation resistance value monitoring module, a thermal management module and a SOC module connected with the battery management system.

[0027] The insulation resistance value monitoring module is used for monitoring the insulation resistance value between the positive and negative electrodes of the battery, the insulation resistance value between the positive and negative electrodes of the battery and the ground, when the insulation resistance is lower than the alarm setting value, the battery management system alarms, and when the insulation resistance is lower than the insulation protection setting value, the battery management system protects shutdown.

[0028] The thermal management module is used to control the operating temperature of the electrolyte in the vanadium redox flow battery system. By detecting the electrolyte temperature of the positive and negative electrodes, when the electrolyte temperature of the positive and negative electrodes is higher than the temperature alarm value, the heat exchange equipment is started and the heat exchange mode is entered. When the electrolyte temperature drops below a certain set value, the heat exchange equipment is stopped.

[0029] The SOC module is used to estimate the state of charge of the vanadium redox flow battery system and evaluate the battery's charge in real time. When the battery SOC reaches 100%, constant voltage float charging is initiated, and the battery management system automatically disconnects the charging circuit. At this time, the battery system can no longer be charged, but it can still discharge. When the battery SOC drops to 0%, discharging stops to ensure that the battery is working in the optimal state.

[0030] A control method for a constant pressure control system in a vanadium redox flow battery pipeline includes the following steps:

[0031] 1) The vanadium redox flow battery system is operated at its initial frequency through the human-machine interaction module. The given pressure parameters, pressure deviation range, and standard values ​​of the operating parameters of the vanadium redox flow battery are set for the positive and negative frequency converters.

[0032] 2) The data acquisition and storage module acquires the operating parameters of the vanadium redox flow battery and sends them to the PLC. The PLC compares the acquired operating parameters with the set standard values. When each parameter reaches the negative range of the set standard value, the battery system first alarms. When each parameter exceeds the standard value, the PLC controls the vanadium redox flow battery system to shut down for protection.

[0033] 3) After the pressure sensor in the data acquisition and storage module acquires the pressure values ​​of the positive and negative electrodes of the vanadium redox flow battery, it sends them to the PLC. The PLC controls the electrolyte pump through the frequency converter based on the deviation between the actual operating pressure of the vanadium redox flow battery system and the target set value.

[0034] Step 3) specifically includes:

[0035] (1) The PLC determines whether the deviation between the actual operating pressure of the vanadium redox flow battery system and the target set value is within the pressure deviation range.

[0036] (2) If the pressure deviation range is not met, the PLC calculates the difference between the two and uses PID control mode to calculate the frequency setpoint and converts it into a 4-20mA signal to be sent to the frequency converter; the frequency converter converts the signal setpoint into frequency output.

[0037] (3) If the pipeline pressure of a certain electrode of the vanadium redox flow battery is lower than the given pressure value, increase the speed of the electrolyte pump that has pressure deviation; conversely, decrease the speed of the electrolyte pump that has pressure deviation, so as to achieve the given pressure value of the pipeline system.

[0038] (4) If the pressure deviation is within the range, the electrolyte pump will maintain its original frequency output.

[0039] A control method for a constant pressure control system in a vanadium redox flow battery pipeline also includes the following steps:

[0040] When the insulation resistance monitoring module detects that the insulation resistance between the positive and negative terminals of the battery and the insulation resistance between the positive and negative terminals of the battery and ground are lower than the alarm setting value, the battery management system will sound an alarm. When the insulation resistance is lower than the insulation protection setting value, the battery management system will shut down for protection.

[0041] When the thermal management module detects that the temperature of the positive and negative electrolytes is higher than the temperature alarm value, it starts the heat exchange equipment and puts it into heat exchange mode. When the electrolyte temperature drops below a certain set value, it stops the heat exchange equipment.

[0042] When the SOC module reaches 100%, constant voltage float charging of the vanadium redox flow battery is executed, and the battery management system automatically disconnects the charging circuit. At this time, the battery system can no longer be charged, but it can still be discharged. When the SOC drops to 0%, the discharge of the vanadium redox flow battery is stopped to ensure that the vanadium redox flow battery works in the optimal state.

[0043] The present invention has the following beneficial effects and advantages:

[0044] 1. This invention optimizes battery system performance, improves electrolyte availability and system efficiency, and promotes the large-scale application of vanadium redox flow batteries.

[0045] 2. This invention ensures that the pipeline pressure of the battery system remains almost constant, optimizes battery performance, and greatly improves the utilization rate of the electrolyte in the battery system. Attached Figure Description

[0046] Figure 1 System functional framework diagram of the battery management system of the present invention;

[0047] Figure 2 The constant pressure control logic block diagram of the present invention;

[0048] Figure 3 A schematic diagram of the pressure control PID principle of this invention. Detailed Implementation

[0049] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0050] The present invention provides a constant pressure control system for a vanadium redox flow battery pipeline, comprising: a battery management system and a constant pressure control system connected thereto.

[0051] The battery management system receives the pressure signals collected from the vanadium redox flow battery pipeline, calculates and compares them with the given pressure parameters, obtains the frequency adjustment parameters, and sends them to the constant pressure control system. At the same time, the battery management system monitors the operating parameters of the vanadium redox flow battery it collects.

[0052] The constant pressure control system receives frequency adjustment parameters and, through PID control mode, adjusts the positive and negative electrode pressure values ​​in the positive and negative electrode pipelines of the vanadium redox flow battery to maintain the positive and negative electrode pressure values ​​at a given pressure value.

[0053] like Figure 1 The diagram shown is a system functional framework diagram of the battery management system of the present invention. The battery management system of the present invention includes: PLC, IO module, human-machine interaction module, communication module and data acquisition and storage module.

[0054] (1) The data acquisition and storage module is connected to the PLC through the IO module and is used to send the acquired vanadium redox flow battery operating parameters to the PLC through the IO module;

[0055] (2) The human-machine interface module is connected to the PLC and uses an HMI display to interact with the PLC and control the operation of the battery management system. At the same time, it can set the alarm values ​​of each vanadium redox flow battery operating parameter and the given pressure parameters of the vanadium redox flow battery. Operators can control the operation of the system through the indicator lights, buttons and selector switches on the control cabinet panel.

[0056] (3) There are multiple IO modules, the number of which corresponds to the interface settings for the data acquisition and storage module to acquire the operating parameters of the vanadium redox flow battery.

[0057] (4) The battery management system has local data display and manual operation functions for each device. The battery management system also has a communication module, which has a reserved Ethernet interface for external communication, facilitating data interaction with third-party monitoring systems. It can also achieve remote data transmission and monitoring through wireless WIFI and 4G networks.

[0058] (5) PLC is used to receive various vanadium redox flow battery operating parameters collected by the data acquisition and storage module, and monitor the vanadium redox flow battery operating parameters according to the alarm values ​​of each vanadium redox flow battery operating parameter set; at the same time, it receives the standard signal of the real-time vanadium redox flow battery pressure value, compares it with the given pressure parameter, obtains the frequency adjustment parameter, and sends it to the constant pressure control system.

[0059] (6) Among them, the operating parameters of the vanadium redox flow battery include: battery voltage, battery charging and discharging current, pipeline system pressure, flow rate, electrolyte temperature, liquid level of positive and negative electrode storage tanks, and voltage of single cell of the stack.

[0060] Regarding the operating parameters of the vanadium redox flow battery, this embodiment collects them through a data acquisition and storage module. The data acquisition and storage module includes: positive and negative electrode flow sensors, positive and negative electrode temperature sensors, voltage sensors, current sensors, liquid level sensors, and pressure sensors connected to the IO module.

[0061] The pressure sensor is installed on the vanadium redox flow battery pipeline to convert the collected pressure signal into a standard 4-20mA signal via an analog input module and send it to the PLC of the battery management system for PID control.

[0062] Positive and negative flow sensors are respectively installed on the positive and negative electrode lines of the vanadium redox flow battery to detect the flow rate on the positive and negative electrode lines of the vanadium redox flow battery.

[0063] Positive and negative electrode temperature sensors are respectively installed on the positive and negative electrode lines of the vanadium redox flow battery to detect the temperature on the positive and negative electrode lines of the vanadium redox flow battery.

[0064] Voltage and current sensors are used to detect the voltage and current values ​​of the vanadium redox flow battery, respectively.

[0065] The liquid level sensor is installed in the positive and negative electrode tanks of the vanadium redox flow battery to detect the liquid level value in the positive and negative electrode tanks.

[0066] (7) This embodiment also includes: an insulation resistance monitoring module, a thermal management module, and a SOC module connected to the battery management system;

[0067] The insulation resistance monitoring module is used to monitor the insulation resistance between the positive and negative terminals of the battery, and the insulation resistance between the positive and negative terminals of the battery and ground respectively. When the insulation resistance is lower than the alarm setting value, the battery management system will sound an alarm; when the insulation resistance is lower than the insulation protection setting value, the battery management system will shut down for protection.

[0068] The thermal management module is used to control the operating temperature of the electrolyte in the vanadium redox flow battery system. By detecting the electrolyte temperature of the positive and negative electrodes, when the electrolyte temperature of the positive and negative electrodes is higher than the temperature alarm value, the heat exchange equipment is started and the heat exchange mode is entered. When the electrolyte temperature drops below a certain set value, the heat exchange equipment is stopped.

[0069] The SOC module is used to estimate the state of charge of the vanadium redox flow battery system and evaluate the battery's charge in real time. When the battery SOC reaches 100%, constant voltage float charging is initiated, and the battery management system automatically disconnects the charging circuit. At this time, the battery system can no longer be charged, but it can still discharge. When the battery SOC drops to 0%, discharging stops to ensure that the battery is working in the optimal state.

[0070] (8) Regarding the constant pressure control system being composed of existing technologies, the constant pressure control system in this embodiment includes: a pressure sensor, a frequency converter, and an electrolyte pump;

[0071] The frequency converter is a fan / pump type, connected to the PLC and electrolyte pump. It receives frequency adjustment parameters from the battery management system and controls the speed of the electrolyte pump to maintain the pressure in the vanadium redox flow battery at a given value. In this embodiment, the frequency converter is controlled by a variable frequency drive, setting its given frequency and controlling its operation mode. This reduces the impact on the power supply when starting the positive and negative pumps, suppresses the motor starting current, and simultaneously adjusts the flow rate and pressure of the battery piping system by regulating the frequency.

[0072] Two electrolyte pumps are provided, one on the positive and one on the negative electrode of the vanadium redox flow battery. The positive and negative electrolyte pumps are independently controlled by two frequency converters. The frequency converters are fan-pump type. The frequency setting and feedback of the frequency converters are controlled by analog signals. The start and stop operation of the frequency converters are controlled by terminals. The power supply of the electrolyte pumps is equipped with overheat, overload and short circuit protection.

[0073] like Figure 2 The diagram shown is a constant pressure control logic block diagram of the present invention. The control method of a constant pressure control system for a vanadium redox flow battery pipeline of the present invention includes the following steps:

[0074] 1) The vanadium redox flow battery system is operated at its initial frequency through the human-machine interaction module. The given pressure parameters, pressure deviation range, and standard values ​​of the operating parameters of the vanadium redox flow battery are set for the positive and negative frequency converters.

[0075] 2) The data acquisition and storage module acquires the operating parameters of the vanadium redox flow battery and sends them to the PLC. The PLC compares the acquired operating parameters with the set standard values. When each parameter reaches the negative range of the set standard value, the battery system first alarms. When each parameter exceeds the standard value, the PLC controls the vanadium redox flow battery system to shut down for protection.

[0076] 3) After the pressure sensor in the data acquisition and storage module acquires the pressure values ​​of the positive and negative electrodes of the vanadium redox flow battery, it sends them to the PLC. The PLC controls the electrolyte pump through the frequency converter based on the deviation between the actual operating pressure of the vanadium redox flow battery system and the target set value.

[0077] 3-1) The PLC determines whether the deviation between the actual operating pressure of the vanadium redox flow battery system and the target set value is within the pressure deviation range;

[0078] 3-2) If the pressure deviation does not meet the range, the PLC calculates the difference between the two and uses PID control mode to calculate the frequency setpoint, which is then converted into a 4-20mA signal and sent to the frequency converter; the frequency converter converts the signal setpoint into a frequency output.

[0079] 3-3) If the pipeline pressure of a certain electrode of the vanadium redox flow battery is lower than the given pressure value, increase the speed of the electrolyte pump that has the pressure deviation; conversely, decrease the speed of the electrolyte pump that has the corresponding pressure deviation, so as to achieve the given pressure value of the pipeline system.

[0080] 3-4) If the pressure deviation is within the range, the electrolyte pump will maintain its original frequency output.

[0081] In this embodiment, a constant pressure control system for a vanadium redox flow battery pipeline also performs the following steps:

[0082] When the insulation resistance monitoring module detects that the insulation resistance between the positive and negative terminals of the battery and the insulation resistance between the positive and negative terminals of the battery and ground are lower than the alarm setting value, the battery management system will sound an alarm. When the insulation resistance is lower than the insulation protection setting value, the battery management system will shut down for protection.

[0083] When the thermal management module detects that the temperature of the positive and negative electrolytes is higher than the temperature alarm value, it starts the heat exchange equipment and puts it into heat exchange mode. When the electrolyte temperature drops below a certain set value, it stops the heat exchange equipment.

[0084] When the SOC module reaches 100%, constant voltage float charging of the vanadium redox flow battery is executed, and the battery management system automatically disconnects the charging circuit. At this time, the battery system can no longer be charged, but it can still be discharged. When the SOC drops to 0%, the discharge of the vanadium redox flow battery is stopped to ensure that the vanadium redox flow battery works in the optimal state.

[0085] like Figure 3 The diagram shows a schematic of the PID control principle of this invention. The core control unit of this invention calculates the pressure deviation and the rate of change of the deviation based on the set pressure value and the actual feedback value from the field pressure sensor. After processing by the PID controller, the analog signal is output to the frequency converter to adjust the motor speed, thereby precisely regulating the pressure value of the battery piping system.

[0086] The proportional gain parameter KP is one of the most important parameters in PID control. Initially, KP can be set to a medium value, and then gradually optimized through step-by-step adjustments based on the actual situation. The integral time parameter TI determines the response speed of the integral action of the PID control, while the derivative time parameter TD determines the response speed of the derivative action.

[0087] Example:

[0088] A 125kW / 500kWh vanadium redox flow battery system consists of two 62.5kW stacks, a constant pressure control system, a battery management system, vanadium redox flow battery pipelines, a cooling system, and other data control subsystems.

[0089] In the initial operation of the vanadium redox flow battery system, the default setpoint frequency for both the positive and negative inverters is 20Hz. At this time, the positive and negative pressure values ​​of the battery pipeline are approximately 0.6 Bar and 0.7 Bar, respectively. When the system pressure is set to 1.0 Bar, the pressure deviation range is set to ±0.05 Bar. Since there is a difference between the actual operating pressure and the target setpoint, the controller calculates the difference, performs PID conversion (in this example, KP is 47, TI is set to 6 seconds, and TD is set to 0.2 seconds), calculates the frequency setpoint, converts it into a 4-20mA signal, and transmits it to the inverter. The inverter converts the signal setpoint into a frequency output, increases the pump speed, and thus achieves the target pressure value of 1.0 Bar in the pipeline system. In this system, the pressure sensor has a range of 0-3 Bar and is a two-wire sensor with an output signal of 4-20mA. The inverter has a power of 4kW, the frequency command signal is an analog signal of 4-20mA, and the frequency output is a 0-10V signal. The inverter starts and stops using multi-terminal control, and the acceleration time is 6s, which can achieve both soft start and ensure response time.

[0090] In summary, this method ensures that the battery system pipeline pressure remains almost constant, optimizes battery performance, and greatly improves the utilization rate of the battery system electrolyte.

[0091] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are 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. A constant pressure control system for piping of a vanadium redox flow battery, characterized by, The application relates to a battery management system and a constant-pressure control system connected therewith. The battery management system is used for receiving collected pressure signals on a vanadium redox flow battery pipeline, performing calculation and comparison with given pressure parameters, obtaining frequency adjustment parameters and sending the frequency adjustment parameters to the constant-pressure control system; meanwhile, the battery management system monitors vanadium redox flow battery operation parameters collected by the battery management system. The constant-pressure control system is used for receiving the frequency adjustment parameters and adjusting positive and negative electrode pressure values in the vanadium redox flow battery positive and negative electrode pipelines through a PID control mode, so that the positive and negative electrode pressure values are kept at given pressure values. The battery management system comprises a PLC, an IO module, a man-machine interaction module, a communication module and a data acquisition and storage module.

2. The constant pressure control system for piping of a vanadium redox flow battery according to claim 1, characterized in that, The data acquisition and storage module is connected with the PLC through the IO module and is used for sending collected various vanadium redox flow battery operation parameters to the PLC through the IO module. The man-machine interaction module is connected with the PLC and is used for interacting with the PLC, controlling the operation of the battery management system and setting alarm values of the various vanadium redox flow battery operation parameters and given pressure parameters of the vanadium redox flow battery. The IO module has a plurality of IO modules, and the number of the IO modules corresponds to the interface settings of the data acquisition and storage module for collecting the vanadium redox flow battery operation parameters. The communication module is an Ethernet interface, a wireless WIFI module or a 4G network module and is connected with the PLC and is used for realizing data interaction between the PLC and a third-party terminal monitoring device. The PLC is used for receiving various vanadium redox flow battery operation parameters collected by the data acquisition and storage module, monitoring the vanadium redox flow battery operation parameters according to the alarm values of the various vanadium redox flow battery operation parameters, receiving real-time standard signals of the vanadium redox flow battery pressure values and comparing the real-time standard signals with given pressure parameters to obtain frequency adjustment parameters and send the frequency adjustment parameters to the constant-pressure control system. The vanadium redox flow battery operation parameters comprise battery voltage, battery charging and discharging current, pipeline system pressure, flow, electrolyte temperature, positive and negative electrode liquid level and single cell voltage of the electric pile.

3. A constant pressure control system for vanadium redox flow battery piping according to claim 2, characterized in that, The data acquisition and storage module comprises positive and negative electrode flow sensors, positive and negative electrode temperature sensors, voltage sensors, current sensors, liquid level sensors and pressure sensors connected with the IO module.

4. A constant pressure control system for vanadium redox flow battery piping according to claim 2, characterized in that, The pressure sensors are installed on the vanadium redox flow battery pipeline and are used for converting collected pressure signals into 4-20 mA standard signals through an analog input module and sending the 4-20 mA standard signals to the PLC of the battery management system for PID control. The positive and negative electrode flow sensors are respectively arranged on the positive and negative electrode pipelines of the vanadium redox flow battery and are used for detecting the flow of the positive and negative electrode pipelines of the vanadium redox flow battery. The positive and negative electrode temperature sensors are respectively arranged on the positive and negative electrode pipelines of the vanadium redox flow battery and are used for detecting the temperature of the positive and negative electrode pipelines of the vanadium redox flow battery. The voltage sensor and the current sensor are respectively used for detecting the voltage value and the current value of the vanadium redox flow battery. The liquid level sensor is arranged in the positive and negative electrode tanks of the vanadium redox flow battery and is used for detecting the liquid level value of the positive and negative electrode tanks. The constant-pressure control system comprises pressure sensors, frequency converters and electrolyte pumps.

5. The constant pressure control system for piping of a vanadium redox flow battery according to claim 1, characterized in that, ​ The frequency converter is a fan water pump type frequency converter, which is connected with the PLC and the electrolyte pump, is used for receiving the frequency adjustment parameter sent by the battery management system, and controls the rotating speed of the electrolyte pump, so that the pressure in the all-vanadium redox flow battery is kept on the given pressure value. The electrolyte pump is provided with two electrolyte pumps, which are respectively arranged on the positive and negative electrode pipelines of the all-vanadium redox flow battery, and are used for detecting the pressure values on the positive and negative electrode pipelines respectively. The two electrolyte pumps are respectively connected with the corresponding frequency converters, and are independently controlled through the corresponding frequency converters.

6. A constant pressure control system for vanadium redox flow battery piping according to claim 1, characterized in that, Further comprising: an insulation resistance value monitoring module, a thermal management module and an SOC module connected with the battery management system; The insulation resistance value monitoring module is used for monitoring the insulation resistance value between the positive and negative electrodes of the battery, the insulation resistance value between the positive and negative electrodes of the battery and the ground, when the insulation resistance is lower than the alarm setting value, the battery management system alarms, and when the insulation resistance is lower than the insulation protection setting value, the battery management system protects and stops; The thermal management module is used for controlling the running temperature of the electrolyte in the all-vanadium redox flow battery system, and the positive and negative electrolyte temperatures are detected, when the positive and negative electrolyte temperatures are higher than the temperature alarm value, the heat exchange equipment is started and put into the heat exchange mode, and when the electrolyte temperature is below a certain setting value, the heat exchange equipment is stopped. The SOC module is used for estimating the state of charge of the all-vanadium redox flow battery system, and the charge capacity of the battery is evaluated in real time, when the battery SOC reaches 100%, the battery is constant-voltage floating charged, the battery management system is automatically disconnected, at this time, the battery system cannot be charged, but can still be discharged, when the battery SOC decreases to 0%, the discharge is stopped, and the battery works in the best state.

7. The control method of claim 1, wherein, The steps include: 1) The initial frequency of the all-vanadium redox flow battery system is run through the man-machine interaction module, the given pressure parameters of the positive and negative frequency converters, the pressure deviation range and the standard value of the all-vanadium redox flow battery running parameters are set; 2) The all-vanadium redox flow battery running parameters collected by the data acquisition and storage module are sent to the PLC, the PLC compares the collected all-vanadium redox flow battery running parameters with the set standard value, when each parameter reaches the set range of the standard value, the battery system first alarms, when each parameter exceeds the standard value, the PLC controls the all-vanadium redox flow battery system to protect and stop; 3) The pressure values of the positive and negative electrodes of the all-vanadium redox flow battery collected by the pressure sensor in the data acquisition and storage module are sent to the PLC, and the PLC controls the electrolyte pump through the frequency converter according to the deviation between the actual running pressure of the all-vanadium redox flow battery system and the target setting value.

8. The control method of claim 7, wherein the control method comprises: The step 3) is specifically: (1) The PLC judges whether the deviation between the actual running pressure of the all-vanadium redox flow battery system and the target setting value conforms to the pressure deviation range; (2) If the pressure deviation range is not met, the PLC calculates the difference, adopts the PID control mode, calculates the frequency given value, and converts it into a 4-20 mA signal sent to the frequency converter; the frequency converter converts the signal given value into a frequency output according to the signal given value. (3) If the pipeline pressure of one electrode of the all-vanadium redox flow battery is lower than the given pressure value, the rotating speed of the electrolyte pump with pressure deviation is increased; otherwise, the rotating speed of the electrolyte pump with pressure deviation is decreased, so that the pipeline system pressure value reaches the given pressure value; (4) If the pressure deviation range is met, the electrolyte pump keeps the original frequency output.

9. The control method of claim 7, wherein the control method comprises: The following steps are also performed: When the insulation resistance value monitoring module monitors that the insulation resistance value between the positive and negative electrodes of the battery, and the insulation resistance value between the positive and negative electrodes of the battery and the ground is lower than the alarm setting value, the battery management system alarms, and when the insulation resistance is lower than the insulation protection setting value, the battery management system protects shutdown; When the thermal management module detects that the positive and negative electrode electrolyte temperature is higher than the temperature alarm value, the heat exchange equipment is started and put into heat exchange mode, and when the electrolyte temperature drops below a certain setting value, the heat exchange equipment is stopped; When the SOC module reaches 100%, the all-vanadium redox flow battery constant voltage floating charging is performed, the battery management system automatically disconnects the charging circuit, at this time the battery system cannot be charged any more, but can still be discharged; when the SOC drops to 0%, the all-vanadium redox flow battery discharging is stopped, ensuring that the all-vanadium redox flow battery works in the best state.

Images