Zinc-based flow battery monitoring and control system

Abstract

The invention relates to a monitoring and control system for a zinc-based flow battery. The monitoring and control system comprises a flow battery controller, an energy recoverer, a pressure regulator, a temperature controller, a heat exchanger, a cold and heat exchange circulating pump, a heat exchange device, a sensor and a master control switch. Multiple physical quantities such as current, voltage, flow velocity, pressure and temperature in the running state of the zinc-based flow battery are detected in real time through the sensor, calculation and analysis are performed by the flow battery controller, and the energy recoverer, the voltage regulator and the temperature controller are controlled; the real-time regulation of physical quantities such as current, voltage, flow velocity, pressure and temperature in the operation process of the zinc-based flow battery is realized, the fine regulation and control of the operation state of the zinc-based flow battery are further realized, the stability and reliability of a flow battery system are improved, and the energy consumption of the system is saved by combining the operation control and maintenance of the flow battery.

Description

Technical Field

[0001] The present invention belongs to the technical field of zinc-based liquid flow batteries, and in particular to a zinc-based liquid flow battery monitoring and control system. Background Art

[0002] The transformation to low-carbon and zero-carbon energy and the reconstruction of the modern energy system are the inevitable choices for achieving the United Nations' sustainable development goals and responding to global climate change. New energy and renewable energy are bound to accelerate their entry into the mainstream of the energy system.

[0003] Liquid flow battery technology has been increasingly valued by countries around the world in recent years due to its advantages such as large energy storage scale, high safety, long charge and discharge cycle life, high cost performance during the life cycle, low environmental load, recyclable battery materials, and environmental friendliness. It has a huge market prospect.

[0004] The monitoring and control systems for flow battery energy storage applications in the prior art are mostly built with general-purpose controllers, which only detect and control the entire flow battery pack, and have the following problems:

[0005] 1. The controller sampling points are insufficient. The existing controller only samples the overall parameters of the liquid flow battery pack, without signal sampling for battery cells and monitoring of various environmental quantities. Therefore, it is impossible to achieve high-precision charge estimation, fault prediction and location, and refined control of battery status.

[0006] 2. In terms of control, it only realizes the overall control of electric power input and output, lacks the control of battery operating environment parameters, and can only use the shutdown method to deal with battery failure and daily maintenance. Battery maintenance requires additional equipment, which increases the construction cost of the energy storage system.

[0007] 3. It is difficult to coordinate control and maintenance. The battery maintenance must be shut down for a long time, which directly affects the overall operating efficiency of the energy storage system and also increases the cost of system maintenance. Summary of the invention

[0008] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a zinc-based liquid flow battery monitoring and control system to realize the monitoring of multiple parameters of zinc-based liquid flow batteries, including: single cell voltage monitoring, battery pack total voltage and current monitoring, electrolyte temperature and flow rate monitoring. Based on the above data, the state of the zinc-based liquid flow battery can be analyzed, including: battery single cell electrode zinc deposition state, battery single cell electrode zinc shedding state, etc. And realize the balanced control of battery cells, electrolyte temperature and flow rate control. Through the above parameter control, the purpose of online maintenance of zinc-based liquid flow batteries can be achieved. Combined with data analysis and prediction, a reasonable battery maintenance strategy can be formulated to complete system maintenance work during system working intervals, thereby saving maintenance costs.

[0009] The technical solution adopted by the present invention to achieve the above-mentioned purpose is: a zinc-based liquid flow battery monitoring and control system, comprising:

[0010] A liquid flow battery controller is used to obtain the status detection information of the liquid flow battery group through sensors arranged in the liquid flow battery group, and analyze the operation of the liquid flow battery group according to the status detection information; and realize the status control of the liquid flow battery group through operating parameter control;

[0011] The main control switch, the input end is connected to the liquid flow battery group, the maintenance end S1 is connected to the voltage regulator, and the battery output end S2 is connected to the external device to realize the switching between maintenance mode and working mode;

[0012] The voltage regulator has an input side connected to the maintenance end of the master control switch and an output side connected to the input end of the energy recovery device; it is used to adjust the voltage of the flow battery group to a voltage level acceptable to the input end of the energy recovery device;

[0013] The energy recovery device has an input end for receiving electric energy and an output end connected to the temperature control unit; it is used to store part of the electric energy and replenish the electric energy to the temperature control unit when the temperature control unit needs electric energy;

[0014] A temperature control unit is used to obtain electrical energy from the energy recovery device or externally and to adjust the water temperature in the heat exchanger through a temperature feedback closed loop;

[0015] The electrolyte circulation pump is used to directly receive control instructions from the liquid flow battery controller to control the flow rate of the electrolyte.

[0016] The liquid flow battery controller comprises:

[0017] A status detection module is used to collect status detection information of the liquid flow battery group; it is directly connected to the single electrode in the liquid flow battery group, and is used to detect the voltage of the single flow battery; it is connected to the main output line of the liquid flow battery group through a voltage sensor, and is used to detect the total voltage of the liquid flow battery group; it is connected to the main output line of the liquid flow battery group through a current sensor, and is used to detect the total current of the liquid flow battery group;

[0018] A calculation module, used to analyze the state of charge of the battery pack according to the single cell voltage, total voltage and total current obtained by the state detection module;

[0019] An operating parameter control module, used to perform at least one of battery cell voltage balancing control and battery pack charging and discharging current control;

[0020] The communication module is used to send the status detection information of the flow battery pack and the control parameters in the operation parameter control module to the host computer.

[0021] The temperature control unit comprises a temperature controller, a heat exchanger, a heat exchange device connected in sequence, and a cold and hot exchange circulation pump connected to the heat exchanger and the heat exchange device;

[0022] The temperature controller is used to obtain electrical energy from the energy recovery device or the outside to drive the heating and cooling of the heat exchanger, and read the temperature value through the temperature sensor preset in the heat exchange device to form a temperature feedback closed loop to adjust the water temperature in the heat exchanger;

[0023] A heat exchanger, used to control the temperature of the electrolyte through a cold and hot exchange circulation pump and a heat exchange device;

[0024] The heat exchange device is embedded in the electrolyte storage tank in the form of a heat exchange tube to achieve temperature control of the electrolyte;

[0025] The cold and heat exchange circulation pump is connected with the heat exchanger and the heat exchange device to form a water circulation for adjusting the electrolyte temperature.

[0026] A method for monitoring and controlling a zinc-based flow battery comprises the following steps:

[0027] First, the flow battery controller detects the voltage of each battery cell. When the difference between the maximum voltage and the minimum voltage exceeds the threshold, and the voltage of any battery cell is not 0 or is negative, it is considered that the flow battery has zinc deposition problems and needs maintenance. The threshold of the voltage difference is obtained through experiments.

[0028] When the flow battery is in an abnormal state, maintenance will be performed at the right time in the next several cycles:

[0029] When the liquid flow battery group is allowed to be deeply discharged, the main control switch is first switched to allow the liquid flow battery group to be connected to the battery output terminal S2 of the main control switch to continue to discharge to the outside;

[0030] When the total voltage of the flow battery group is lower than the minimum threshold voltage of the external device connected to the outlet of the flow battery group and cannot continue to discharge, the flow battery controller controls the master control switch to switch to the maintenance terminal S1 to connect the flow battery group to the maintenance circuit as a maintenance mode; in the maintenance mode, the voltage regulator adjusts the total voltage of the flow battery group to the voltage that the energy recovery device can receive, and the remaining power of the flow battery group is discharged to the energy recovery device through the voltage regulator for temporary storage;

[0031] When the total voltage of the flow battery pack reaches the lower threshold voltage of the voltage regulator, the discharge is cut off, and the flow battery controller continues to discharge the battery cells until each cell of the flow battery pack is completely discharged, completing the entire deep discharge process;

[0032] Then, the master control switch is switched to the battery outlet terminal S2, that is, adjusted to the working mode.

[0033] A method for monitoring and controlling a zinc-based flow battery comprises the following steps:

[0034] First, the flow battery controller detects the voltage of each battery cell. When the voltage of any battery cell is 0 or negative, it is considered that zinc has fallen off inside the battery, causing electrolyte blockage, and maintenance is required:

[0035] This is achieved specifically by controlling the temperature controller and the electrolyte circulation pump, including the following steps:

[0036] The temperature controller controls the heat exchanger, temporarily raising the temperature of the electrolyte through the heat exchange device, and at the same time increases the speed of the cold and hot exchange circulation pump to improve the heat exchange efficiency and speed up the temperature increase;

[0037] Control the electrolyte circulation pump to increase the speed and thus increase the electrolyte flow rate;

[0038] The removal of electrolyte blockage is accelerated under the dual effects of temperature and flow rate;

[0039] By detecting the battery cell voltage in real time, it is determined whether the blockage problem has been cleared. If so, the temperature and flow rate are reduced to normal values.

[0040] The present invention has the following beneficial effects and advantages:

[0041] The present invention detects multiple physical quantities of zinc-based liquid flow batteries in real time, and realizes refined and three-dimensional control of zinc-based liquid flow batteries through real-time adjustment of physical quantities such as electrical, temperature, and flow in the zinc-based liquid flow batteries, thereby ensuring the stability and reliability of the liquid flow battery system, and saving system energy consumption by combining the operation control and maintenance of the liquid flow battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 System framework diagram of the present invention.

[0043] Figure 2 Flow chart of the method for regulating zinc deposition problem according to an embodiment of the present invention.

[0044] Figure 3 Flow chart of the method for regulating zinc deposition blockage problem according to an embodiment of the present invention. DETAILED DESCRIPTION

[0045] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0046] The invention discloses a zinc-based liquid flow battery monitoring and control system, which comprises: a liquid flow battery controller, an energy recovery device, a voltage regulator, a temperature controller, a heat exchanger, a cold and hot circulation pump, a heat exchange device, a sensor, and a master control switch.

[0047] The liquid flow battery status detection module in the liquid flow battery controller is connected to the battery cells in the liquid flow battery group to collect the cell voltage and is connected to the main output line of the battery group through a voltage / current sensor; the master control switch is a single-pole double-throw switch, which can select the positive pole of the battery to be connected to the positive output line of the battery or the voltage regulator, and the driving end of the master control switch is connected to the I / O module in the liquid flow battery controller; the output end of the voltage regulator is connected to the energy recovery device; the temperature controller is used to control the temperature of the heat exchanger, and finally adjust the temperature of the battery electrolyte through the heat exchange circulation pump; the electrolyte circulation pump, the heat exchange circulation pump, the temperature controller, the energy recovery device, and the voltage regulator are all connected to the liquid flow battery controller through a bus. The flow battery controller shown judges the current state of the flow battery by reading parameters such as the voltage of each battery cell in the flow battery group, the total voltage of the battery group, the total current of the battery group, and controls the flow battery group by adjusting the temperature and flow rate of the flow battery electrolyte in real time, or controls the flow battery system to enter the maintenance mode; the flow battery state includes: charge state, battery cell balance, electrode zinc deposition state, electrode zinc deposition shedding state, and battery state adjustment processing; the maintenance mode includes: deep discharge of the flow battery group through the voltage regulator, and balance and deep discharge of the battery cell voltage through the flow battery balance control module.

[0048] like Figure 1 As shown, a zinc-based liquid flow battery monitoring and control system, the monitoring and control system comprises:

[0049] The flow battery controller is responsible for the status detection, data analysis and calculation, operation parameter control, data communication, and system coordination control of the flow battery system.

[0050] The status detection of the liquid flow battery system is divided into two parts. One part is the direct parameter detection of the liquid flow battery group, which is realized through the liquid flow battery status detection module inside the controller. The voltage detection channel of the battery detection analog front-end chip in the detection module is directly connected to the liquid flow battery monomer electrode, which is used to detect the voltage of the liquid flow battery monomer. The total voltage detection channel in the detection module is connected to the total output line of the liquid flow battery group through a voltage sensor; the total current detection channel is connected to the total output line of the liquid flow battery group through a current sensor, which is used to detect the overall voltage and current of the battery group. The other part of the system status detection is the detection of the parameters of each component device in the system. This part of the data is obtained from each device by the controller through the system bus module through the internal bus.

[0051] Data analysis and calculation is the controller's judgment on the system's operating conditions based on the system's state parameters combined with various algorithms, and is the responsibility of the calculation module in the controller. Data analysis and calculation mainly include: battery pack state of charge estimation, battery remaining life estimation, zinc deposition fault prediction, zinc shedding fault prediction, system maintenance requirements, etc.

[0052] The operating parameter control of zinc-based liquid flow batteries includes electrical parameter control and environmental parameter control. Electrical parameter control mainly includes battery cell voltage balancing control and battery pack charge / discharge current control. Battery cell voltage balancing is completed by the liquid flow battery balancing control module in the controller, and the balancing control module adjusts the voltage of the battery cells to be consistent through active and passive balancing. Battery pack charge and discharge current control is completed by the controller sending parameters to the charger and discharge machine outside the system through the communication module.

[0053] Data communication means that the controller can send the system operation status information to the external upper controller and control equipment through the communication module, such as charger, PCS and other equipment. The upper controller can also send control information to the flow battery controller according to the overall energy scheduling situation to complete the system control.

[0054] Intra-system coordinated control means that the controller can control the parameters of other devices in the system according to the control strategy to achieve the purpose of system-level control.

[0055] The voltage and current sensors are connected to the battery main output line, converting the total voltage and current signals of the battery pack into low-level systems that can be received by the controller, while also having the function of signal isolation.

[0056] The common end of the single-pole double-throw master control switch is connected to the positive electrode of the battery pack, one end (S1) is connected to the voltage regulator, and the other end (S2) is connected to the positive electrode of the battery main output line. It is mainly used for switching the battery pack connection topology.

[0057] The input side of the voltage regulator is connected to the master switch and the output side is connected to the energy recovery device. Its main function is to adjust the voltage of the flow battery group to the voltage level acceptable to the input end of the energy recovery device. The voltage regulator is composed of a step-up / step-down module, a monitoring module, and a protection module.

[0058] The input end of the energy recovery device is connected to the output end of the voltage regulator to receive electric energy, and the output end is connected to the electrical equipment in the system, which is the temperature controller. Its main function is to temporarily store part of the electric energy, and when the electrical equipment needs electric energy, it can replenish it. The energy recovery device is composed of an internal electric energy storage module, an output voltage stabilization module, a control module, and a protection module.

[0059] The temperature controller is used to obtain electrical energy from the energy recovery device or the outside to drive the heating and cooling in the heat exchanger, and reads the temperature value through the temperature sensor preset in the heat exchange device to form a temperature feedback closed loop to adjust the water temperature in the heat exchanger; the heat exchanger is used to control the temperature of the electrolyte through the heat exchange circulation pump and the heat exchange device; the heat exchange device is embedded in the electrolyte storage tank in the form of a heat exchange tube to achieve temperature control of the electrolyte; the heat exchange circulation pump is connected to the heat exchanger and the heat exchange device to form a water circulation to adjust the temperature of the electrolyte.

[0060] The electrolyte circulation pump constitutes the electrolyte flow rate regulation part of the system. The electrolyte circulation pump directly receives the control instructions of the flow battery controller to adjust the output to achieve the purpose of controlling the flow rate of the electrolyte.

[0061] When the zinc-based flow battery is running, the flow battery controller detects the flow battery status data in real time through the flow battery status detection module, including: the voltage of the battery cell, the total voltage of the battery pack, and the total current of the battery pack. And the information is processed in real time through the calculation module. After data processing, further status information is obtained, including: battery pack charge state estimation, battery remaining life estimation, zinc deposition fault prediction, zinc shedding fault prediction, system maintenance requirements, etc.

[0062] The liquid flow battery controller can report status information to the station control layer controller in real time through the communication module. The communication module can be equipped with modules that support the physical layer interface of multiple data buses such as Ethernet, RS485 bus, CAN bus, etc. according to the data interface requirements of the station control layer. 4G / 5G communication modules can also be optionally installed to realize remote data monitoring.

[0063] The flow battery controller can control the system components according to the state of the zinc-based flow battery. The specific control measures are as follows:

[0064] like Figure 2 As shown, first, the liquid flow battery controller detects the voltage of each battery cell. When the difference between the maximum voltage and the minimum voltage exceeds the threshold, and the voltage of any battery cell is not 0 or is negative, it is considered that the liquid flow battery has a zinc deposition problem and needs maintenance.

[0065] Furthermore, the threshold of the voltage difference is obtained through experiments.

[0066] When the flow battery is in an abnormal state, maintenance will be performed at the right time in the next several cycles:

[0067] When the liquid flow battery group is allowed to be deeply discharged, the main control switch is first switched to allow the liquid flow battery group to be connected to the battery output terminal S2 of the main control switch to continue to discharge to the outside;

[0068] When the total voltage of the flow battery group is lower than the minimum threshold voltage of the external device connected to the outlet of the flow battery group and cannot continue to discharge, the flow battery controller controls the master control switch to switch to the maintenance terminal S1 to connect the flow battery group to the maintenance circuit as a maintenance mode; in the maintenance mode, the voltage regulator adjusts the total voltage of the flow battery group to the voltage that the energy recovery device can receive, and the remaining power of the flow battery group is discharged to the energy recovery device through the voltage regulator for temporary storage;

[0069] When the total voltage of the flow battery pack reaches the lower threshold voltage of the voltage regulator, the discharge is cut off, and the flow battery controller continues to discharge the battery cells until each cell of the flow battery pack is completely discharged, completing the entire deep discharge process;

[0070] Then, the master control switch is switched to the battery outlet terminal S2, that is, adjusted to the working mode.

[0071] like Figure 3 As shown, the flow battery controller first detects the voltage of each battery cell. When the voltage of any battery cell is 0 or negative, it is considered that zinc has fallen off inside the battery, causing electrolyte blockage, and maintenance is required:

[0072] This is achieved specifically by controlling the temperature controller and the electrolyte circulation pump, including the following steps:

[0073] The temperature controller controls the heat exchanger, temporarily raising the temperature of the electrolyte through the heat exchange device, and at the same time increases the speed of the cold and hot exchange circulation pump to improve the heat exchange efficiency and speed up the temperature increase;

[0074] Control the electrolyte circulation pump to increase the speed and thus increase the electrolyte flow rate;

[0075] The removal of electrolyte blockage is accelerated under the dual effects of temperature and flow rate;

[0076] By detecting the battery cell voltage in real time, it is determined whether the blockage problem has been cleared. If so, the temperature and flow rate are reduced to normal values.

Claims

1. A zinc-based flow battery monitoring and control system, characterized in that: include: A liquid flow battery controller, used to obtain status detection information of the liquid flow battery group through sensors arranged in the liquid flow battery group, and analyze the operation of the liquid flow battery group according to the status detection information; Realize the state control of the flow battery pack through operating parameter control; The main control switch, the input end is connected to the liquid flow battery group, the maintenance end S1 is connected to the voltage regulator, and the battery output end S2 is connected to the external device to realize the switching between maintenance mode and working mode; The voltage regulator has an input side connected to the maintenance end of the master control switch and an output side connected to the input end of the energy recovery device; Used to adjust the voltage of the flow battery group to a voltage level acceptable to the input end of the energy recovery device; The energy recovery device has an input end for receiving electric energy and an output end connected to the temperature control unit; it is used to store part of the electric energy and replenish the electric energy to the temperature control unit when the temperature control unit needs electric energy; A temperature control unit is used to obtain electrical energy from the energy recovery device or externally and to adjust the water temperature in the heat exchanger through a temperature feedback closed loop; The electrolyte circulation pump is used to directly receive control instructions from the liquid flow battery controller to control the flow rate of the electrolyte.

2. The zinc-based liquid flow battery monitoring and control system according to claim 1, characterized in that: The liquid flow battery controller comprises: A status detection module is used to collect status detection information of the liquid flow battery group; it is directly connected to the single electrode in the liquid flow battery group, and is used to detect the voltage of the single flow battery; it is connected to the main output line of the liquid flow battery group through a voltage sensor, and is used to detect the total voltage of the liquid flow battery group; it is connected to the main output line of the liquid flow battery group through a current sensor, and is used to detect the total current of the liquid flow battery group; A calculation module, used to analyze the state of charge of the battery pack according to the single cell voltage, total voltage and total current obtained by the state detection module; An operating parameter control module, used to perform at least one of battery cell voltage balancing control and battery pack charging and discharging current control; The communication module is used to send the status detection information of the flow battery pack and the control parameters in the operation parameter control module to the host computer.

3. The zinc-based liquid flow battery monitoring and control system according to claim 1, characterized in that: The temperature control unit comprises a temperature controller, a heat exchanger, a heat exchange device connected in sequence, and a cold and hot exchange circulation pump connected to the heat exchanger and the heat exchange device; The temperature controller is used to obtain electrical energy from the energy recovery device or the outside to drive the heating and cooling of the heat exchanger, and read the temperature value through the temperature sensor preset in the heat exchange device to form a temperature feedback closed loop to adjust the water temperature in the heat exchanger; A heat exchanger, used to control the temperature of the electrolyte through a cold and hot exchange circulation pump and a heat exchange device; The heat exchange device is embedded in the electrolyte storage tank in the form of a heat exchange tube to achieve temperature control of the electrolyte; The cold and hot exchange circulation pump is connected with the heat exchanger and the heat exchange device to form a water circulation for adjusting the electrolyte temperature.

4. A method for monitoring and controlling a zinc-based liquid flow battery, characterized in that: The following steps are involved: First, the flow battery controller detects the voltage of each battery cell. When the difference between the maximum voltage and the minimum voltage exceeds the threshold, and the voltage of any battery cell is not 0 or is negative, it is considered that the flow battery has zinc deposition problems and needs maintenance. The threshold of the voltage difference is obtained through experiments. When the flow battery is in an abnormal state, maintenance will be performed at a later time in the next several cycles: When the liquid flow battery group is allowed to be deeply discharged, the main control switch is first switched to allow the liquid flow battery group to be connected to the battery output terminal S2 of the main control switch to continue to discharge to the outside; When the total voltage of the flow battery group is lower than the minimum threshold voltage of the external device connected to the outlet of the flow battery group and cannot continue to discharge, the flow battery controller controls the master control switch to switch to the maintenance terminal S1 to connect the flow battery group to the maintenance circuit as a maintenance mode; in the maintenance mode, the voltage regulator adjusts the total voltage of the flow battery group to the voltage that the energy recovery device can receive, and the remaining power of the flow battery group is discharged to the energy recovery device through the voltage regulator for temporary storage; When the total voltage of the flow battery pack reaches the lower threshold voltage of the voltage regulator, the discharge is cut off, and the flow battery controller continues to discharge the battery cells until each cell of the flow battery pack is completely discharged, completing the entire deep discharge process; Then, the master control switch is switched to the battery output terminal S2, that is, adjusted to the working mode.

5. The method for monitoring and controlling a zinc-based flow battery according to claim 4, characterized in that: The following steps are involved: First, the flow battery controller detects the voltage of each battery cell. When the voltage of any battery cell is 0 or negative, it is considered that zinc has fallen off inside the battery, causing electrolyte blockage, and maintenance is required: This is achieved specifically by controlling the temperature controller and the electrolyte circulation pump, including the following steps: The temperature controller controls the heat exchanger, temporarily raising the temperature of the electrolyte through the heat exchange device, and at the same time increases the speed of the cold and hot exchange circulation pump to improve the heat exchange efficiency and speed up the temperature increase; Control the electrolyte circulation pump to increase the speed and thus increase the electrolyte flow rate; The removal of electrolyte blockage is accelerated under the dual effects of temperature and flow rate; By detecting the battery cell voltage in real time, it is determined whether the blockage problem has been cleared. If so, the temperature and flow rate are reduced to normal values.

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