A deep discharge control method and system for a sedimentation type liquid flow battery

Abstract

The present invention discloses a method and system for controlling deep discharge of a sedimentation type liquid flow battery. The system collects the status information of the liquid flow battery module of the sedimentation type liquid flow battery in real time according to the maintenance instruction of the host computer, and analyzes the operating status of the liquid flow battery module according to the voltage change of the liquid flow battery module during operation. The liquid flow battery module is maintained by adopting the deep discharge method, and a variety of discharge strategies are divided to generate operating parameters. The deep discharge control of the liquid flow battery module is realized by online automatic control of the operating parameters. The present invention can delay the accumulation of obsolete deposits, the shedding of deposits, and the generation of dendrites, effectively prolonging the service life of the sedimentation type liquid flow battery and improving its operating efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid flow batteries, and in particular to a deep discharge control method and system for a sedimentation type liquid flow battery. Background Art

[0002] Sedimentation flow battery systems, represented by sedimentation flow batteries, have the advantages of low cost and high safety, and have received increasing attention. However, during the redox process of charge and discharge of sedimentation flow batteries, a certain amount of metal elements will be deposited on the electrodes. The conventional discharge process cannot remove the deposits well. After multiple cycles, the deposited layer becomes thicker and falls off and cannot participate in subsequent redox reactions, which reduces the cycle performance of sedimentation flow batteries. Due to the different roughness of the electrode surface, uneven deposition will produce dendrites, resulting in reduced battery coulomb efficiency and capacity, shortened battery life, and other problems. In severe cases, it will pierce the diaphragm, causing the battery to short-circuit and cause irreversible damage.

[0003] The current mainstream maintenance method for sedimentation flow batteries is to use monitoring equipment to evaluate the health of the battery, mainly the number of cycles and the energy efficiency of charge and discharge, and regularly replace the electrolyte according to empirical values, or perform deep discharge to maintain the working efficiency of the battery. The existing methods for deep discharge maintenance either require manual shutdown, affecting the normal use of the system; or only perform quantitative current discharge through a fixed load, which takes a long time to maintain and has problems such as incomplete discharge. Summary of the invention

[0004] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a method and system for controlling deep discharge of a sedimentation-type liquid flow battery, collect the status information of the liquid flow battery module of the sedimentation-type liquid flow battery in real time according to the maintenance instructions of the host computer, and analyze the operating status of the liquid flow battery module according to the voltage changes during the operation of the liquid flow battery module. The liquid flow battery module is maintained by a deep discharge method, a variety of discharge strategies are divided, and operating parameters are generated. The deep discharge control of the liquid flow battery module is achieved by online automatic control of the operating parameters. The present invention can delay the accumulation of obsolete deposits, the shedding of deposits, and the generation of dendrites, effectively extending the service life of the sedimentation-type liquid flow battery and improving its operating efficiency.

[0005] The technical solution adopted by the present invention to achieve the above-mentioned purpose is:

[0006] A deep discharge control system for a sedimentation type liquid flow battery, the sedimentation type liquid flow battery comprises an electrolyte storage tank, a liquid flow battery module, and an electrolyte circulation path between the two; the deep discharge control system is used to control the liquid flow battery module to perform deep discharge; the deep discharge control system comprises:

[0007] The program-controlled electronic load is connected to the positive and negative electrodes of the flow battery module, receives the discharge operation parameters of the module controller, and outputs control instructions to the maintenance switch;

[0008] The maintenance switch is connected in series between the flow battery module and the programmable electronic load to form a discharge circuit; it switches the deep discharge mode by opening and closing the switch;

[0009] A temperature control device is provided in the electrolyte circulation passage, and is used to adjust the temperature of the heat transfer medium of the heat exchange device through a temperature feedback closed loop, thereby changing the electrolyte temperature in the electrolyte circulation passage;

[0010] A flow rate feedback control device, comprising a circulation pump and a flow meter connected in series to the electrolyte circulation passage, for receiving control instructions from the module controller to control the flow rate of the electrolyte;

[0011] The module controller is connected to the control interfaces of the above-mentioned electrical components through a control bus, and is used to obtain the status detection information of the liquid flow battery module through the voltage detection channel of the programmable electronic load, and analyze the deep discharge operation of the liquid flow battery module according to the status detection information; and realize the deep discharge state control of the liquid flow battery module through the operation parameter control.

[0012] The module controller comprises:

[0013] The state detection module is used to collect the state detection information of the liquid flow battery module; it is connected to the voltage detection channel of the programmable electronic load to collect the voltage state information and discharge current state information of the liquid flow battery module; it is connected to the temperature sensor preset in the heat exchange device to read the electrolyte temperature state information; it is connected to the flow meter to collect the electrolyte flow rate state information;

[0014] An analysis module, used to analyze the deep discharge state according to the voltage state information, discharge current state information, electrolyte temperature state information, and electrolyte flow rate state information of the flow battery module obtained by the state detection module;

[0015] An operating parameter control module, used to control the discharge parameters to implement at least one of the multiple discharge strategies of the flow battery module; the multiple discharge strategies include normal voltage discharge, undervoltage discharge, overvoltage discharge, and trickle discharge;

[0016] The communication module is used to send the status detection information of the flow battery module and the control parameters in the operation parameter control module to the host computer.

[0017] The temperature control device comprises a temperature controller, a heat exchange device, and a heat exchange pipeline connected in sequence;

[0018] Heat exchange device, using heater and fan equipment to heat or circulate heat around the heat exchange pipe;

[0019] The heat exchange pipe is a pipe at the entrance of the electrolyte circulation channel that is densely wound to transfer the temperature of the electrolyte flowing through the heat exchange pipe through the heat exchange device;

[0020] The temperature controller receives the temperature control parameters of the module controller, drives the heater and fan equipment to heat or cool the heat exchange pipe, and reads the temperature value through the temperature sensor preset in the heat exchange pipe, forming a temperature feedback closed loop to adjust the temperature of the electrolyte in the heat exchange pipe.

[0021] A method for controlling deep discharge of a sedimentation type liquid flow battery comprises the following steps:

[0022] First, the module controller receives maintenance instructions from the host computer and collects voltage status information of the flow battery module;

[0023] Secondly, the deep discharge operation of the flow battery module is analyzed according to the voltage change of the flow battery module during operation, and the operation parameters of at least one of normal voltage discharge control, undervoltage discharge control, overvoltage discharge control, and overvoltage abnormal control are divided and generated;

[0024] Finally, the discharge circuit is controlled by operating parameters to achieve the corresponding deep discharge strategy control of the flow battery module.

[0025] The collecting of voltage status information of the liquid flow battery module includes sequentially executing the following steps: turning on the maintenance switch to open the path between the liquid flow battery module and the programmable electronic load; turning on the programmable electronic load to measure the operating voltage of the liquid flow battery module using the voltage detection channel of the programmable electronic load as the voltage status information.

[0026] The deep discharge operation analysis includes: determining whether the operation voltage falls within the threshold range of the corresponding strategy, obtaining the result of executing a certain discharge strategy, and generating the discharge operation parameters of the corresponding strategy.

[0027] Furthermore, the normal pressure discharge control includes:

[0028] Set the programmable electronic load mode to constant current discharge mode and perform single or multiple discharge cycles;

[0029] And the discharge current value is gradually reduced to a certain percentage of the rated current in each discharge cycle;

[0030] Monitor the total voltage of the flow battery module in real time to determine whether to leave the flow battery module stationary or discharge it in the next round;

[0031] Repeat the above process for multiple rounds of discharge until the standing time exceeds the time threshold and the battery voltage is still less than 95% of the rated voltage and enters the undervoltage discharge process. Otherwise, when the discharge current setting value is less than the preset minimum percentage threshold of the battery rated current, the constant current discharge ends and the trickle discharge process begins.

[0032] Furthermore, the undervoltage discharge process includes:

[0033] By controlling the temperature controller to increase the temperature of the electrolyte flowing into the flow battery module to a maximum percentage threshold of the temperature value, the molecular activity is increased;

[0034] By controlling the circulation pump to increase the flow rate of the electrolyte flowing into the flow battery module within the maximum flow rate range, the number of molecules near the electrode is increased;

[0035] Start the program-controlled electronic load and detect the total voltage of the flow battery module in real time, and adjust the constant current discharge value of the program-controlled electronic load in real time during each round of discharge. Q = measured total voltage / rated voltage × rated current × K; K is an empirical parameter;

[0036] Repeat the above process for multiple rounds of discharge until the current setting value Q is less than the minimum percentage threshold of the rated current of the flow battery module and enters the trickle discharge process, or the total voltage measured by the battery module is less than the minimum voltage of the module and enters the trickle discharge process.

[0037] Furthermore, the overvoltage discharge process includes:

[0038] First, the programmable electronic load mode is set to the constant current discharge mode, and the discharge current value is set to the rated current of the flow battery module for multiple rounds of discharge;

[0039] Secondly, the total voltage of the liquid flow battery module is monitored in real time during the discharge process. When the total voltage is less than the rated voltage of the liquid flow battery module, the normal pressure discharge process is entered.

[0040] Furthermore, the trickle discharge process includes:

[0041] First, the programmable electronic load mode is set to constant resistance discharge mode, and the resistance value is set to 100 times the internal resistance of the flow battery module;

[0042] Secondly, monitor the status. If the programmable electronic load alarms for overcurrent, set the resistance value to a thousand times the internal resistance of the flow battery module and discharge for several minutes. Set the resistance value to a hundred times the internal resistance of the flow battery module again and continue discharging until the programmable electronic load does not alarm for overcurrent and then discharges once more to complete the discharge.

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

[0044] 1. The present invention can realize online rapid maintenance of the sedimentation-type liquid flow battery by automatically regulating the sedimentation state, thereby reducing the system maintenance cost and improving the system operation efficiency.

[0045] 2. The present invention designs a step-by-step deep discharge strategy, which can effectively remove the deposits at the early stage of generation, thereby delaying the accumulation of old deposits, the shedding of deposits, and the generation of dendrites to a certain extent.

[0046] 3. Compared with the existing methods, the deep discharge maintenance strategy of the present invention greatly shortens the discharge maintenance time and makes the discharge thorough and effective. This method can effectively extend the service life of the sedimentation flow battery and improve the operating efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a system framework diagram of the present invention.

[0048] Figure 2 FIG. 4 is a flow chart of a normal pressure discharge according to an embodiment of the present invention.

[0049] Figure 3 FIG. 4 is a flow chart of undervoltage discharge according to an embodiment of the present invention.

[0050] Figure 4 4 is an overvoltage discharge flow chart of an embodiment of the present invention.

[0051] Figure 5 This is a trickle discharge flow chart of an embodiment of the present invention. DETAILED DESCRIPTION

[0052] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0053] The embodiment of the present invention provides a method and system for controlling deep discharge of a sedimentation type liquid flow battery, which realizes online rapid maintenance of the sedimentation type liquid flow battery, and can effectively remove the sediment in the early stage of generation, thereby delaying the accumulation of old sediments, sediment shedding, and the generation of dendrites to a certain extent. This method can effectively extend the service life of the sedimentation type liquid flow battery and improve its operating efficiency.

[0054] In a first aspect, an embodiment of the present invention provides a deep discharge control system for a sedimentation type liquid flow battery, such as Figure 1As shown, the sedimentation type liquid flow battery includes an electrolyte storage tank, a liquid flow battery module, and an electrolyte circulation path between the two; the deep discharge control system is used to control the liquid flow battery module to perform deep discharge; the deep discharge control system includes: a module controller, a maintenance switch, a programmable electronic load, a temperature control device, a flow rate feedback control device, etc. The programmable electronic load is connected to the positive and negative electrodes of the liquid flow battery module, and the maintenance switch is connected in series between the liquid flow battery module and the programmable electronic load to form a discharge circuit; the temperature control device is connected in series to the electrolyte circulation path to control the temperature of the electrolyte flowing into the liquid flow battery module; the flow rate feedback control device includes a circulation pump and a flow meter connected in series to the electrolyte circulation path to control the speed of the electrolyte flowing into the liquid flow battery module; the module controller is connected to the control interface of the maintenance switch, the programmable electronic load, the temperature control device, the circulation pump and the flow meter through a control bus.

[0055] The programmable electronic load can operate in constant current and constant resistance modes. In constant current mode, within the range of 0V to the rated voltage of the flow battery module, constant current discharge can be performed at any value within the range of 0A to the rated current of the flow battery module, and the discharge current is continuously adjustable. In constant resistance mode, within the range of 0V to the rated voltage of the flow battery module, the resistance setting range is 100 times the internal resistance of the flow battery module to open circuit. The programmable electronic load must be equipped with a voltage detection module that can read the total voltage of the flow battery module in real time. The module controller is connected to the control interface of the programmable electronic load through a control bus, and can control its start / stop, operation mode, discharge current value and resistance value.

[0056] The maintenance switch is a DC switch, the rated voltage of the switch is greater than 1.2 times the maximum voltage of the liquid flow battery module, the rated current of the switch is greater than 1.5 times the rated current of the liquid flow battery module, and the module controller can be connected to the control interface of the maintenance switch through a wire and can control the opening / closing of the maintenance switch.

[0057] The temperature control device includes a temperature controller, a heat exchange device, and a heat exchange pipe connected in sequence; the heat exchange device uses a heater and a fan device to heat or circulate the surrounding environment of the heat exchange pipe; the heat exchange pipe uses a dense winding method for the pipe at the entrance of the electrolyte circulation channel to conduct temperature to the electrolyte flowing through the heat exchange pipe through the heat exchange device; and temperature sensors are set at the entrance and exit of the heat exchange pipe; the temperature controller receives the temperature control parameters of the module controller, drives the heater and the fan device to heat or cool the heat exchange pipe, and reads the temperature value through the temperature sensor preset in the heat exchange pipe, forming a temperature feedback closed loop to adjust the temperature of the electrolyte in the heat exchange pipe. Thus, the electrolyte flows in from the entrance of the heat exchange pipe, exchanges heat through the heat exchange pipe, and then flows out from the outlet and is controlled to be the set temperature.

[0058] The flow rate feedback control device includes a circulation pump and a flow meter connected in series to the electrolyte circulation passage, wherein the circulation pump needs to be able to control the flow rate and lift and has a control interface. The circulation pump receives the control instruction of the module controller to control the flow rate of the electrolyte, and the flow meter receives the control instruction of the module controller to collect the flow rate status information of the electrolyte.

[0059] The module controller adopts an embedded real-time controller and has a control interface for equipment / devices, which can read and control the status. The module controller also needs to have an uplink communication interface connected to the upper controller to receive maintenance instructions. Specifically, the module controller has the following built-in program modules, including:

[0060] The state detection module is used to collect the state detection information of the liquid flow battery module; it is connected to the voltage detection channel of the programmable electronic load to collect the voltage state information and discharge current state information of the liquid flow battery module; it is connected to the temperature sensor preset in the heat exchange device to read the electrolyte temperature state information; it is connected to the flow meter to collect the electrolyte flow rate state information;

[0061] An analysis module, used to analyze the deep discharge state according to the voltage state information, discharge current state information, electrolyte temperature state information, and electrolyte flow rate state information of the flow battery module obtained by the state detection module;

[0062] An operating parameter control module, used to control the discharge parameters to implement at least one of the multiple discharge strategies of the flow battery module; the multiple discharge strategies include normal voltage discharge, undervoltage discharge, overvoltage discharge, and trickle discharge;

[0063] The communication module is used to send the status detection information of the flow battery module and the control parameters in the operation parameter control module to the host computer.

[0064] In a second aspect, an embodiment of the present invention further provides a method for controlling deep discharge of a sedimentation type liquid flow battery, the control method comprising:

[0065] When the module controller receives the maintenance instruction from the upper controller, it first turns on the maintenance switch to open the path between the liquid flow battery module and the programmable electronic load. Then turn on the programmable electronic load, and use the voltage detection channel of the programmable electronic load to measure the total open circuit voltage of the liquid flow battery module. When the total open circuit voltage is within ±5% of the rated voltage of the liquid flow battery module, it enters the normal voltage discharge process; when the total open circuit voltage of the battery is lower than 95% of the rated voltage of the liquid flow battery, it enters the undervoltage discharge process; when the total open circuit voltage of the battery is higher than 105% of the rated voltage of the liquid flow battery and less than 120% of the rated voltage of the liquid flow battery module, it enters the overvoltage discharge process; when the total open circuit voltage of the battery is not less than 120% of the rated voltage of the liquid flow battery, the battery is in an abnormal overvoltage state, and it is necessary to shut down the alarm and exit maintenance.

[0066] The normal pressure discharge process is as follows: Figure 2 As shown, first set the programmable electronic load mode to constant current discharge mode, and the initial value of the discharge current is set to the rated current of the flow battery. Start the programmable electronic load to discharge the flow battery module, and monitor the total voltage of the flow battery module in real time. When the total voltage is less than the minimum voltage of the battery, stop discharging and let the flow battery module stand.

[0067] The reason for the static flow battery module is that chemical batteries have a reaction hysteresis phenomenon. When the active substances inside the battery decrease, the reaction speed slows down and cannot continue to support the battery voltage. It is necessary to wait for the active substances in the battery to continue to react. While the battery is static, the battery will continue to react, causing the open circuit voltage of the battery to rise. When the battery voltage rises back to the rated voltage of the battery, the next round of discharge will continue.

[0068] Before starting the next round of discharge, first adjust the current value of the programmable electronic load discharge to 80% of the previous round of discharge current value. Then start the programmable electronic load again to discharge the liquid flow battery module, and monitor the total voltage of the liquid flow battery module in real time. When the total voltage is less than the minimum voltage, stop discharging and let the liquid flow battery module stand again.

[0069] Repeat the above process for multiple rounds of discharge until the static time exceeds 30s and the battery voltage is still less than 95% of the rated voltage, and enter the undervoltage discharge process; otherwise, if the discharge current setting value is less than 10% of the rated current of the battery, the constant current discharge is completed and the trickle discharge process is entered, otherwise the current value of the programmable electronic load discharge is adjusted to 80% of the previous round of discharge current value, and the programmable electronic load is started again to discharge the liquid flow battery module.

[0070] The undervoltage discharge process is as follows: Figure 3As shown, firstly, the temperature of the electrolyte flowing into the flow battery module is increased by controlling the temperature controller to 120% of the original temperature value (not exceeding the maximum temperature that the flow battery module can withstand), and then the flow rate of the electrolyte flowing into the flow battery module is increased by controlling the circulation pump to 150% of the original flow rate (not exceeding the maximum flow rate that the flow battery module can withstand). According to the collision and activation molecular theory in electrochemistry, it helps to increase the reaction speed of the flow battery module.

[0071] The collision and activated molecule theory states that the prerequisite for electrochemical reactions is that the molecules of the reactants must collide. The reaction rate is proportional to the number of collisions between the reactant molecules per unit time. However, not every collision can cause a reaction. Collisions that can cause chemical reactions are called effective collisions. The more effective collisions there are per unit time, the greater the reaction rate. Increasing the flow rate can increase the number of molecules near the electrode, while increasing the temperature can increase the activity of the molecules.

[0072] Start the programmable electronic load and detect the total voltage of the liquid flow battery module in real time. Use the formula Q = measured total voltage / rated voltage × rated current × K to set the constant current value Q of the programmable electronic load for discharge. K is an empirical parameter, take 0.8. During the discharge process, the above formula is continuously used to adjust the set value Q of the constant current discharge current in real time. When the current setting value is less than 10% of the rated current of the liquid flow battery module, the trickle discharge process begins. Otherwise, it is necessary to continue to judge that the measured total voltage of the liquid flow battery module is less than the minimum voltage of the liquid flow battery module, and then enter the trickle discharge process, otherwise return to the set constant current value Q of the programmable electronic load to start the next discharge.

[0073] The overvoltage discharge process is as follows: Figure 4 As shown, first, the programmable electronic load mode is set to the constant current discharge mode, the discharge current value is set to the rated current of the liquid flow battery module for discharge, and the total voltage of the liquid flow battery module is monitored in real time during the discharge process. When the total voltage is less than the rated voltage of the liquid flow battery module, the normal voltage discharge process is entered again, otherwise multiple rounds of discharge are performed in a cycle.

[0074] The trickle discharge process, such as Figure 5 As shown, first set the program-controlled electronic load mode to constant resistance discharge mode, and the constant resistance value is set to 100 times the internal resistance value of the liquid flow battery module. If the program-controlled electronic load overcurrent alarm occurs, the constant resistance value needs to be set to 1000 times the internal resistance value of the liquid flow battery module. After discharging for 120s, the constant resistance value is set to 100 times the internal resistance value of the liquid flow battery module. If the program-controlled electronic load does not have an overcurrent alarm, it needs to discharge for another 120s before the deep discharge is completed, and the module controller reports the completion status.

[0075] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A deep discharge control system for a sedimentation type liquid flow battery, the sedimentation type liquid flow battery comprising an electrolyte storage tank, a liquid flow battery module, and an electrolyte circulation path therebetween; The deep discharge control system is used to control the deep discharge of the flow battery module; it is characterized by: The deep discharge control system comprises: The program-controlled electronic load is connected to the positive and negative electrodes of the flow battery module, receives the discharge operation parameters of the module controller, and outputs control instructions to the maintenance switch; The maintenance switch is connected in series between the flow battery module and the programmable electronic load to form a discharge circuit; it switches the deep discharge mode by opening and closing the switch; A temperature control device is provided in the electrolyte circulation passage, and is used to adjust the temperature of the heat transfer medium of the heat exchange device through a temperature feedback closed loop, thereby changing the electrolyte temperature in the electrolyte circulation passage; A flow rate feedback control device, comprising a circulation pump and a flow meter connected in series to the electrolyte circulation passage, for receiving control instructions from the module controller to control the flow rate of the electrolyte; The module controller is connected to the control interfaces of the above-mentioned electrical components through the control bus, and is used to obtain the state detection information of the liquid flow battery module through the voltage detection channel of the programmable electronic load, and analyze the deep discharge operation of the liquid flow battery module according to the state detection information; and realize the deep discharge state control of the liquid flow battery module through the operation parameter control; the module controller includes: The state detection module is used to collect the state detection information of the liquid flow battery module; it is connected to the voltage detection channel of the programmable electronic load to collect the voltage state information and discharge current state information of the liquid flow battery module; it is connected to the temperature sensor preset in the heat exchange device to read the electrolyte temperature state information; it is connected to the flow meter to collect the electrolyte flow rate state information; An analysis module, used to analyze the deep discharge state according to the voltage state information, discharge current state information, electrolyte temperature state information, and electrolyte flow rate state information of the flow battery module obtained by the state detection module; An operating parameter control module, used to control the discharge parameters to implement at least one of the multiple discharge strategies of the flow battery module; the multiple discharge strategies include normal voltage discharge, undervoltage discharge, overvoltage discharge, and trickle discharge; The communication module is used to send the status detection information of the flow battery module and the control parameters in the operation parameter control module to the host computer.

2. A sedimentation type liquid flow battery deep discharge control system according to claim 1, characterized in that: The temperature control device comprises a temperature controller, a heat exchange device, and a heat exchange pipeline connected in sequence; Heat exchange device, using heater and fan equipment to heat or circulate heat around the heat exchange pipe; The heat exchange pipe is a pipe at the entrance of the electrolyte circulation channel that is densely wound to transfer the temperature of the electrolyte flowing through the heat exchange pipe through the heat exchange device; The temperature controller receives the temperature control parameters of the module controller, drives the heater and fan equipment to heat or cool the heat exchange pipe, and reads the temperature value through the temperature sensor preset in the heat exchange pipe, forming a temperature feedback closed loop to adjust the temperature of the electrolyte in the heat exchange pipe.

3. A method for controlling deep discharge of a sedimentation type liquid flow battery, characterized in that: The method is implemented based on a sedimentation type liquid flow battery deep discharge control system according to claim 1, and the method comprises the following steps: First, the module controller receives maintenance instructions from the host computer and collects voltage status information of the flow battery module; Secondly, the deep discharge operation of the flow battery module is analyzed according to the voltage change of the flow battery module during operation, and the operation parameters of at least one of normal voltage discharge control, undervoltage discharge control, overvoltage discharge control, and overvoltage abnormal control are divided and generated; Finally, the discharge circuit is controlled by operating parameters to achieve the corresponding deep discharge strategy control of the flow battery module.

4. A method for controlling deep discharge of a sedimentation type liquid flow battery according to claim 3, characterized in that: The collecting of voltage status information of the liquid flow battery module includes sequentially executing the following steps: turning on the maintenance switch to open the path between the liquid flow battery module and the programmable electronic load; turning on the programmable electronic load to measure the operating voltage of the liquid flow battery module using the voltage detection channel of the programmable electronic load as the voltage status information.

5. A sedimentation flow battery deep discharge control method according to claim 3, characterized in that: The deep discharge operation analysis includes: determining whether the operation voltage falls within the threshold range of the corresponding strategy, obtaining the result of executing a certain discharge strategy, and generating the discharge operation parameters of the corresponding strategy.

6. A method for controlling deep discharge of a sedimentation type liquid flow battery according to claim 3, characterized in that: The discharge strategy is a normal voltage discharge process including: executing a constant current discharge mode and gradually reducing the discharge current value in each round; repeating multiple rounds of discharge to determine whether to enter an undervoltage discharge process or a trickle discharge process.

7. A method for controlling deep discharge of a sedimentation type liquid flow battery according to claim 3, characterized in that: The discharge strategy is an undervoltage discharge process including: increasing the electrolyte temperature and electrolyte flow rate flowing into the liquid flow battery module; detecting the total voltage of the liquid flow battery module in real time and adjusting the set value Q of the constant current discharge current; repeating multiple rounds of discharge until the discharge current decreases to a threshold or the total voltage decreases to a threshold, and then entering the trickle discharge process.

8. A method for controlling deep discharge of a sedimentation flow battery according to claim 3, characterized in that: The discharge strategy is an overvoltage discharge process including: first, setting the programmable electronic load mode to a constant current discharge mode, and setting the discharge current value to the rated current discharge of the liquid flow battery module; secondly, monitoring the total voltage of the liquid flow battery module in real time, and when the total voltage is less than the rated voltage of the liquid flow battery module, entering the normal voltage discharge process.

9. A method for controlling deep discharge of a sedimentation type liquid flow battery according to claim 6 or 7, characterized in that: The trickle discharge process includes: first, setting the programmable electronic load mode to a constant resistance discharge mode, and setting the resistance value to a hundred times the internal resistance of the liquid flow battery module; secondly, monitoring the status, if the programmable electronic load alarms for overcurrent, setting the resistance value to a thousand times the internal resistance of the liquid flow battery module and discharging for several minutes, and then setting the resistance value to a hundred times the internal resistance of the liquid flow battery module again, and continuing to discharge until the programmable electronic load does not have an overcurrent alarm and then performs another discharge to complete the discharge.

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