A flow battery system health state evaluation recovery device and method

Abstract

This application relates to the field of flow battery technology, and in particular to a device and method for assessing and restoring the health status of a flow battery system. The device includes an energy storage system, an venting system, a flow battery health restoration system, and a battery management system. During operation, the state of charge (SOH) value of each battery module is calculated by measuring parameters such as the charge and discharge energy, thereby obtaining the SOH assessment value of that battery module. Simultaneously, when the SOH assessment values ​​of multiple battery modules in the system are lower than the limit, the electrolyte with the low SOH assessment value is placed in a comprehensive SOH restoration tank for reduction, thereby achieving the goal of restoring the health status of the entire system.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of flow battery, and in particular to a flow battery system health state evaluation recovery device and method. BACKGROUND

[0002] The safety and reliability of the battery system is the most concerned problem in the application of the battery energy storage system, especially in large-scale battery energy storage. The accurate characterization of the SOH index is beneficial to master the available capacity of the battery system, improve the dispatchable characteristics of the system and the economy of the battery system operation. The SOH of the battery system is an important index to judge the battery failure, aging and current available capacity. The change of SOH reflects the change of the available capacity of the battery system. At present, the definition of SOH at home and abroad is not uniform, mainly in the aspects of capacity, internal resistance, cycle number and peak power and so on, which is relatively widely used in lead-acid batteries and lithium batteries and other solid-state battery systems.

[0003] The accurate evaluation and prediction of the SOH of the battery system can effectively avoid the overuse of the battery system and the occurrence of safety accidents, which has important significance for improving the safety and reliability of the battery system operation. The recovery of SOH also has important significance in improving the safety and reliable operation level of the battery energy storage system. Once the SOH index decreases to a certain value, or appears the trend of accelerated change, the system should give a warning for the operation of the battery system, provide conditions for timely maintenance measures to ensure the safe and reliable operation of the battery system, and at the same time should execute a certain process to recover the SOH of the system, so that the system can maintain efficient operation. At present, the accurate evaluation of SOH and the timely recovery of the system SOH have become a problem to be solved. SUMMARY

[0004] In order to solve the problems in the prior art, the present application provides a flow battery system health state evaluation recovery device and method.

[0005] In a first aspect, the present application discloses a flow battery system health state evaluation recovery method applied to a flow battery, wherein the flow battery comprises an energy storage system, and the energy storage system comprises at least one battery module, and the method comprises the following steps:

[0006] Under different powers, the initial open circuit voltage, the initial charging electric energy and the initial discharging electric energy of the battery module stack after standing are detected under different charge and discharge cycles, and an initial state of charge value matched with the initial open circuit voltage is determined.

[0007] Specifically, after the battery module is at rest, it refers to the moment when the electrolyte starts circulating until the first full charge of the stack, and no charge and discharge operation is performed, the positive and negative stack voltages are not initially 0. The initial open circuit voltage refers to the positive stack voltage U 222P and the negative stack voltage U 222N These two voltage values are the basis data for calculating the initial state of charge value. In the first calibration charge and discharge cycle, the initial state of charge value SOC1 is calculated using the preset open circuit voltage and SOC relationship formula SOC f (U 222P −U 222N ). At the same time, the charging energy E i1 and the discharging energy E o1 are measured and recorded by the DC power meter. In order to ensure the accuracy and reliability of the data, it is necessary to measure and record multiple times at different powers, so as to more comprehensively reflect the performance characteristics of the battery module under different working conditions. Under the rated charge and discharge power, three calibration charge and discharge cycles are continuously completed. In each cycle: record the initial state of charge value (SOC1, SOC2, SOC3), record the charging energy (E i1 , E i2 ), record the discharging energy (E o1 , E o2 ).

[0008] It should be noted that in the flow battery, in order to accurately evaluate the health state (SOH) of the battery module, a series of standardized charge and discharge cycles are needed to collect data. These charge and discharge cycles need to be carried out at different constant power levels. The process conditions of the charge and discharge cycle are as follows:

[0009] The first charge and discharge cycle: before starting the first charge and discharge cycle, the battery module needs to be pre-charged to an initial SOC of 20%. Ensuring that all battery modules start testing at the same initial state, reducing the impact of initial state differences on test results. Perform the charging process: start charging the battery module from an SOC of 20% until the SOC corresponding to the stack open circuit voltage reaches 80%. The purpose is to charge within a known SOC range and record the energy change during charging. Stop condition: when the SOC corresponding to the stack open circuit voltage reaches 80%, stop charging. Ensuring that the charging process is completed within the predetermined SOC range, avoiding overcharging.

[0010] The second charge and discharge cycle: after the first charge and discharge cycle ends, the battery module needs to be rested for 2 hours. Perform the discharge process: from the condition of the end of the first charge and discharge, discharge the battery module until the SOC corresponding to the open circuit voltage of the stack reaches 20%. The purpose is to discharge within a known SOC range and record the change in electrical energy during the discharge process. Stop condition: when the SOC corresponding to the open circuit voltage of the stack reaches 20%, stop discharging. This ensures that the discharge process is completed within the predetermined SOC range, avoiding over-discharge. The third charge and discharge cycle: after the second charge and discharge cycle ends, the battery module is again rested for 2 hours, and the charging process is performed: from the condition of the end of the second charge and discharge, charge the battery module until the SOC corresponding to the open circuit voltage of the stack reaches 80%. The purpose is to charge within a known SOC range and record the change in electrical energy during the charging process. Stop condition: when the SOC corresponding to the open circuit voltage of the stack reaches 80%, stop charging. This ensures that the charging process is completed within the predetermined SOC range, avoiding overcharging.

[0011] Secondly, adjust the charge and discharge power of the battery module to be tested to be 90%, 80%, 70%, 60%, 50%, and 40% of the rated power, respectively. The purpose of this step is to test at different power levels to evaluate the performance of the battery module under different working conditions. At each set power level, repeat the above three charge and discharge cycles. The purpose of this step is to collect complete charge and discharge data at different power levels to provide sufficient data support for subsequent analysis.

[0012] Based on the initial state of charge value, the initial charging electrical energy, and the initial discharging electrical energy, determine the calibration unit charging electrical energy and the calibration unit discharging electrical energy corresponding to each change in state of charge by a preset threshold value, and construct a first mapping relationship for representing different charging powers and the calibration unit charging electrical energy, and a second mapping relationship for representing different discharging powers and the calibration unit discharging electrical energy.

[0013] Based on the first mapping relationship and the second mapping relationship, determine an actual state of charge value in actual operation, and determine an actual unit discharging electrical energy corresponding to each change in the actual state of charge value by a preset threshold value;

[0014] Obtain the unit discharging electrical energy corresponding to the actual discharging power from the second mapping relationship, and determine a health state evaluation value corresponding to the battery module according to the actual unit discharging electrical energy and the actual discharging power, to evaluate and restore the health state of the flow battery through the health state evaluation value.

[0015] In one embodiment, the initial open circuit voltage, the initial charging electric energy and the initial discharging electric energy of the battery module stack after standing for different periods of time under different powers are detected, and an initial state of charge value matched with the initial open circuit voltage is determined, including:

[0016] For any power, the initial open circuit voltage, the initial charging electric energy and the initial discharging electric energy of the battery module stack after standing for different periods of time under different powers are detected; wherein the preset charging and discharging period includes at least a first period for the first charging, a second period for discharging and a third period for the second charging.

[0017] The initial state of charge value matched with the initial open circuit voltage is determined through the preset correspondence between the state of charge and the open circuit voltage.

[0018] In one embodiment, the initial state of charge value, the initial charging electric energy and the initial discharging electric energy are used to determine the calibrated unit charging electric energy and the calibrated unit discharging electric energy corresponding to each change of the state of charge by a preset threshold, including:

[0019] Based on the initial state of charge value, the state of charge change amount in each charging and discharging period is determined.

[0020] A matrix containing the initial charging electric energy and the initial discharging electric energy is constructed, and a vector containing the initial charging electric energy, the initial discharging electric energy and the state of charge change amount is constructed.

[0021] The matrix and the vector are used to determine the calibrated unit charging electric energy corresponding to each increase of the state of charge by the preset threshold, and to determine the calibrated unit discharging electric energy corresponding to each decrease of the state of charge by the preset threshold.

[0022] Specifically, at the beginning of each charging and discharging period, the initial state of charge value is recorded: SOC1 is the initial state of charge value of the first charging and discharging period; SOC2 is the initial state of charge value of the second charging and discharging period; SOC3 is the initial state of charge value of the third charging and discharging period; in each charging and discharging period, the state of charge change amount is calculated: ΔSOC1 = SOC2 - SOC1; ΔSOC2 = SOC3 - SOC2.

[0023] A matrix A containing the initial charging electric energy and the initial discharging electric energy is constructed:

[0024]

[0025] A vector B containing the initial charging electric energy, the initial discharging electric energy and the state of charge change amount is constructed:

[0026] The vector B includes a discharging process matrix and a charging matrix:

[0027]

[0028] Using the matrix A and the vector B, the calibrated unit charging energy k is calculated when the state of charge SOC changes by a preset threshold (preferably 1%) 1p and the calibrated unit discharging energy k 2p :

[0029]

[0030] Through the above detailed steps, the calibrated unit charging energy k 1p and the calibrated unit discharging energy k 2p of the flow battery module at the rated power when the SOC changes by 1% can be accurately calculated. These calibrated energy values are key parameters for subsequent evaluation of the battery module health state (SOH) and recovery operations. Through these parameters, the performance changes of the battery module can be dynamically monitored, and the health problems of the battery module can be discovered and handled in a timely manner, ensuring the efficient and safe operation of the flow battery system.

[0031] For each set of charging and discharging power levels, the above steps are performed to calculate the calibrated unit charging energy k1 and the calibrated unit discharging energy k2 at each power. Mathematical models (such as polynomial fitting, linear regression, etc.) are used to fit the data of k1 and k2 with power P, to obtain the first mapping relationship and the second mapping relationship for representing different powers and the calibrated charging energy and the calibrated discharging energy, respectively.

[0032] In one embodiment, the determination of the actual state of charge value in actual operation based on the first mapping relationship and the second mapping relationship includes:

[0033] At the current power, the initial charge state value when the battery module starts is obtained; and the current charging power and the current discharging power of the battery module in actual operation are obtained;

[0034] According to the current charging power and the current discharging power of the battery module, the calibrated unit charging energy and the calibrated unit discharging energy at the current power are found from the first mapping relationship and the second mapping relationship;

[0035] Using the initial charge state value when starting, the current charging energy, the current discharging energy, the calibrated unit charging energy at the current power, and the calibrated unit discharging energy at the current power, the actual state of charge value in actual operation is determined.

[0036] Specifically, in order to accurately evaluate the state of charge (SOC) of the battery module in actual operation, it is necessary to dynamically calculate the current target state of charge value by using the pre-established mapping relationship. At the start of the battery module, the initial state of charge value SOC0 at the start is recorded. This value is calculated by measuring the initial stack open circuit voltage (OCV) after the stack is at rest and using the pre-set OCV-SOC relationship formula. In actual operation, the current charging energy E i and the current discharging energy E o .

[0037] According to the current charging and discharging power P, the calibrated unit charging energy k1 under the current power is found from the first mapping relationship This mapping relationship is established through the previous calibration process and reflects the unit charging energy for each 1% increase in SOC under different powers.

[0038] Similarly, according to the current charging and discharging power P, the calibrated unit discharging energy k2 under the current power is found from the second mapping relationship This mapping relationship reflects the unit discharging energy for each 1% decrease in SOC under different powers. Using the initial state of charge value SOC0 at the start, the current charging energy E i , the current discharging energy E o , the calibrated unit charging energy k1 under the current power, and the unit calibrated discharging energy k2 under the current power, the actual state of charge value in operation is calculated. The specific calculation formula is:

[0039]

[0040] In one embodiment, the unit discharging energy corresponding to the actual discharging power is obtained from the second mapping relationship, and the health state evaluation value corresponding to the battery module is determined according to the unit discharging energy and the actual discharging power, including:

[0041] Obtaining the unit discharging energy corresponding to the actual discharging power from the second mapping relationship;

[0042] Determining the ratio between the rated unit discharging energy and the calibrated rated unit discharging energy;

[0043] Determining the ratio as the health state evaluation value corresponding to the battery module.

[0044] Specifically, during operation, the rated unit discharging energy k 2E is recorded when the state of charge value of the battery module to be tested decreases by 1%. This data is obtained by real-time monitoring of the discharging process of the battery module. The calibrated rated unit discharging energy k 2p is obtained from the calibration process. The second mapping relationship is established by the previous calibration process, which reflects the calibrated unit discharge energy required for the SOC to decrease by 1% at different powers. The actual rated unit discharge energy k 2E is calculated by the ratio between the calibrated rated discharge energy k 2p . This ratio reflects the health status of the battery module under the current operating state. The specific formula is:

[0045]

[0046] The above ratio is determined as the health status evaluation value (SOH) corresponding to the battery module. This value is a dimensionless index for evaluating the health status of the battery module. The closer the SOH value is to 1, the better the health status of the battery module; the lower the SOH value, the worse the health status of the battery module.

[0047] According to the characteristics of the current power station and a large amount of experimental data calibration, the relationship between the SOH value and the unit discharge energy k2 and the discharge power P can be obtained, so that the current system SOH value can be calculated by the unit discharge energy k2 and the discharge power P of the battery module to be tested under the current discharge power, which decreases by 1% in real time:

[0048]

[0049] In an embodiment, the health status of the flow battery is evaluated and recovered by the health status evaluation value, comprising:

[0050] When and only when the health status evaluation value of one battery module is less than a preset evaluation threshold, the positive and negative electrolytes of the battery module less than the preset evaluation threshold are mixed uniformly after the operation ends, so as to recover the flow battery;

[0051] When the health status evaluation values of at least two battery modules are less than a preset evaluation threshold, the positive and negative electrolytes of all battery modules are mixed uniformly after the operation ends, so as to recover the flow battery.

[0052] Specifically, during the operation of the multi-battery module flow battery, if and only if the health status evaluation value SOH of one battery module is lower than the preset evaluation threshold SOH re (e.g. 75%), and the health status evaluation values SOH of other battery modules are not lower than SOH re , then the battery module is locally recovered after the current operation ends. The specific operation is to open the liquid outlet valve and the liquid mixing balance valve of the battery module, so that the positive and negative electrolytes of the battery module are mixed uniformly. This helps to recover the performance of the battery module.

[0053] In the operation of the multi-cell module flow battery, when the state of health evaluation value SOH of at least two cell modules is lower than a preset evaluation threshold SOH re (e.g. 75%), after the current operation is completed, global recovery is performed on all cell modules. Specifically, the recovery tank connection liquid inlet valve and the recovery tank connection liquid outlet valve are opened, and the opening degree of the recovery tank connection liquid inlet valve and the recovery tank connection liquid outlet valve of each cell module is adjusted according to the state of health evaluation value SOH of each cell module. The higher the state of health evaluation value SOH, the lower the opening degree; when the state of health evaluation value SOH is greater than 90%, the valve opening degree is 0; when the state of health evaluation value SOH is less than SOH re , the valve opening degree is 100%. This helps to mix the positive and negative electrolytes of all cell modules, and realizes global mixing of the whole system. After global mixing is completed, the recovery tank connection liquid inlet valve and the recovery tank connection liquid outlet valve are closed, the recovery tank liquid outlet valve and the recovery tank liquid return valve are opened, and the balance flow pump is started to perform reductive charging on the flow battery health recovery system. During charging, the open circuit voltage SOC value SOC h corresponding to the current recovery tank stack voltage of the flow battery health recovery system is calculated using the voltage difference of the recovery tank stack voltage and the previously obtained correlation formula of the open circuit voltage and SOC.

[0054]

[0055] The flow battery health recovery system is reductively charged until the SOC value SOC h corresponding to the stack open circuit voltage reaches 60%, and then the charging is completed. After charging is completed, the recovery tank connection liquid inlet valve and the recovery tank connection liquid outlet valve are reopened to mix the recovered electrolyte with the electrolyte in the original system. After mixing is completed, the recovery tank connection liquid inlet valve and the recovery tank connection liquid outlet valve are closed. At this time, the recovery of SOH is completed.

[0056] In a second aspect, the application discloses a device for the health state evaluation and recovery method described above, which comprises an energy storage system, an exhaust system, a flow battery health recovery system and a battery management system; wherein,

[0057] The energy storage system is used for storing and releasing electric energy, and comprises a plurality of sub-cell modules, including a liquid storage tank, a stack group, a flow pump, a liquid outlet valve, a liquid return valve, a bypass auxiliary valve, a liquid mixing balance valve, a stack sensor group, an out-of-stack sensor group, a tank body sensor group and a direct current power meter of each cell module;

[0058] The exhaust system is used for collecting and discharging the byproduct gas generated by the system, and comprises a nitrogen tank, a nitrogen valve, a tank body gas inlet valve of each cell module, a tank body gas outlet valve, a tank body gas inlet valve of the recovery tank and a tank body gas outlet valve of the recovery tank;

[0059] The flow battery health recovery system is used for recovering the health state of the flow battery, comprising a comprehensive SOH recovery tank, an auxiliary positive electrode tank, an auxiliary stack group, a balance flow pump, a recovery tank connection inlet valve, a recovery tank connection outlet valve, a recovery tank outlet valve, a recovery tank return valve, a recovery tank stack inlet sensor group, a recovery tank stack outlet sensor group, a recovery tank tank body sensor group, and an auxiliary positive electrode tank tank body sensor group;

[0060] The battery management system is used for integrating the energy storage system, the exhaust system, and the flow battery health recovery system.

[0061] In one embodiment, the outlet valve of each battery module is arranged between the liquid storage tank of each battery module and the stack group of each battery module;

[0062] There is a pipeline branch between the outlet valve of each battery module and the liquid storage tank of each battery module, and between the outlet valve of each battery module and the stack group of each battery module;

[0063] The pipeline branch between the outlet valve of each battery module and the liquid storage tank of each battery module connects the energy storage system and the flow battery health recovery system;

[0064] The pipeline branch between the outlet valve of each battery module and the stack group of each battery module is sequentially provided with the flow pump of each battery module and the stack inlet sensor group of each battery module;

[0065] The stack inlet sensor group of each battery module comprises a stack inlet temperature sensor and a stack inlet voltage sensor;

[0066] The mixed liquid balance valve of each battery module is arranged between the pipeline branch between the outlet valve of each battery module and the stack group of each battery module and the stack group of each battery module;

[0067] The return valve of each battery module is arranged between the stack group of each battery module and the liquid storage tank of each battery module;

[0068] The return valve of each battery module and the stack group of each battery module are provided with the stack outlet sensor group of each battery module;

[0069] The stack outlet sensor group of each battery module comprises a stack outlet temperature sensor, a stack outlet voltage sensor, and a stack outlet flow sensor;

[0070] There is a pipeline branch between the return valve of each battery module and the liquid storage tank of each battery module;

[0071] The pipeline branch between the return valve of each battery module and the liquid storage tank of each battery module connects the energy storage system and the flow battery health recovery system;

[0072] The bypass auxiliary valve of each battery module is arranged between the pipe branch between the liquid outlet valve of each battery module and the liquid storage tank of each battery module;

[0073] The tank body sensor group of each battery module is arranged on the liquid storage tank of each battery module;

[0074] The tank body sensor group of each battery module comprises a tank body liquid pressure sensor and a tank body gas pressure sensor.

[0075] In one embodiment, the recovery tank communication liquid inlet valve is arranged between the pipe branch between the liquid outlet valve of each battery module in the energy storage system and the liquid storage tank of each battery module and the comprehensive SOH recovery tank;

[0076] There is a pipe branch connected to the liquid storage tank of each battery module in the energy storage system between the recovery tank communication liquid inlet valve and the comprehensive SOH recovery tank;

[0077] The recovery tank communication liquid outlet valve is arranged between the pipe branch between the comprehensive SOH recovery tank and the liquid return valve of each battery module in the energy storage system and the liquid storage tank of each battery module;

[0078] The recovery tank liquid outlet valve, the balance liquid flow pump, and the recovery tank stack inlet sensor group are arranged in sequence between the comprehensive SOH recovery tank or the auxiliary positive electrode tank and the auxiliary stack group;

[0079] The recovery tank stack inlet sensor group comprises a recovery tank stack inlet temperature sensor and a recovery tank stack inlet voltage sensor;

[0080] The recovery tank stack outlet sensor group and the recovery tank liquid return valve are arranged in sequence between the auxiliary stack group and the comprehensive SOH recovery tank or the auxiliary positive electrode tank;

[0081] The recovery tank stack outlet sensor group comprises a recovery tank stack outlet temperature sensor and a recovery tank stack outlet flow sensor;

[0082] The recovery tank tank body sensor group is arranged on the comprehensive SOH recovery tank;

[0083] The recovery tank tank body sensor group comprises a recovery tank tank body liquid pressure sensor and a recovery tank tank body gas pressure sensor;

[0084] The auxiliary positive electrode tank tank body sensor group is arranged on the auxiliary positive electrode tank;

[0085] The auxiliary positive electrode tank tank body sensor group comprises an auxiliary positive electrode tank tank body liquid pressure sensor and an auxiliary positive electrode tank tank body gas pressure sensor.

[0086] In one embodiment, the nitrogen valve is arranged after the nitrogen tank; a pipeline branch after the nitrogen valve is connected to the liquid storage tank of each battery module and the comprehensive SOH recovery tank of the flow battery health recovery system, respectively;

[0087] The tank inlet valve of each battery module is arranged between the pipeline branch after the nitrogen valve and the liquid storage tank of each battery module;

[0088] The tank outlet valve of each battery module is arranged between the liquid storage tank of each battery module and the gas recovery device;

[0089] The tank inlet valve of the recovery tank is arranged between the pipeline branch after the nitrogen valve and the comprehensive SOH recovery tank or the auxiliary positive tank;

[0090] The tank outlet valve of the recovery tank is arranged between the comprehensive SOH recovery tank or the auxiliary positive tank and the gas recovery device.

[0091] When the liquid level of each battery module deviates, the following effects are achieved:

[0092] Case 1: When the liquid level of the liquid storage tank of a certain battery module is too high on one side, the part of the electrolyte that exceeds the safe height will flow into the comprehensive SOH recovery tank through the overflow pipe, thereby ensuring that the system can still operate safely;

[0093] Case 2: Due to the side reaction gas generated during operation, the gas pressure in a certain liquid storage tank is too large, at this time, the nitrogen gas can be used to replace the side reaction gas in the liquid storage tank through the exhaust system, and the side reaction gas is discharged into the gas recovery device;

[0094] Case 3: In the process of liquid level balancing or large blending, in order to improve the mixing efficiency, nitrogen gas can be added to the liquid storage tank with higher liquid level to speed up the flow rate of the liquid, while avoiding the negative pressure being too high to cause air to be sucked into the tank.

[0095] In summary, the present application has the following at least one beneficial technical effect:

[0096] The SOC of each battery module can be calculated more accurately by using the arrangement of the sensor group of each battery module.

[0097] The SOH of each battery module can be calculated more accurately by using the arrangement of the sensor group of each battery module.

[0098] The system can achieve the purpose of SOH recovery by charging and reducing the electrolyte in the comprehensive SOH recovery tank;

[0099] The system can adjust the air pressure through the exhaust system, thereby accelerating the speed of liquid level balance or large blending, and can use the method of injecting nitrogen to exhaust the by-product reaction gas to the gas recovery device, thereby ensuring the safe operation of the system. BRIEF DESCRIPTION OF DRAWINGS

[0100] Figure 1 is the overall system relationship diagram of the embodiment of the present application;

[0101] Figure 2 is the full system pipeline structure schematic diagram;

[0102] Figure 3 is the SOH recovery branch schematic diagram of the sub-cell module;

[0103] Figure 4 is the full system gas path schematic diagram;

[0104] Figure 5 is the position schematic diagram of the sensor of the stack and the auxiliary pipeline;

[0105] Figure 6 is the independent pipeline diagram of the health recovery system of the liquid flow system;

[0106] Figure 7 is the relative relationship diagram of the equipment of the single cell module.

[0107] BRIEF DESCRIPTION OF DRAWINGS

[0108] 01, liquid storage tank of each battery module; 01P, positive electrode liquid storage tank of the battery module; 01N, negative electrode liquid storage tank of the battery module; 01PA, positive electrode liquid storage tank of the battery module A; 01NA, negative electrode liquid storage tank of the battery module A; 01PB, positive electrode liquid storage tank of the battery module B; 01NB, negative electrode liquid storage tank of the battery module B;

[0109] 02, comprehensive SOH recovery tank;

[0110] 03, auxiliary positive tank;

[0111] 04, nitrogen tank;

[0112] 05, stack group of each battery module; 05A, stack group of the battery module A; 05B, stack group of the battery module B;

[0113] 06, auxiliary stack group;

[0114] 07, liquid flow pump of each battery module; 07P, positive electrode liquid flow pump of each battery module; 07N, negative electrode liquid flow pump of each battery module; 07PA, positive electrode liquid flow pump of the battery module A; 07NA, negative electrode liquid flow pump of the battery module A; 07PB, positive electrode liquid flow pump of the battery module B; 07NB, negative electrode liquid flow pump of the battery module B;

[0115] 08, balancing liquid flow pump of each battery module; 08P, positive electrode balancing liquid flow pump; 08N, negative electrode balancing liquid flow pump;

[0116] 09, liquid outlet valve of each battery module; 09P, positive electrode liquid outlet valve of each battery module; 09N, negative electrode liquid outlet valve of each battery module;

[0117] 10, liquid return valve of each battery module; 10P, positive electrode liquid return valve of each battery module; 10N, negative electrode liquid return valve of each battery module;

[0118] 11, bypass auxiliary valve of each battery module; 11P, positive electrode bypass auxiliary valve of each battery module; 11N, negative electrode bypass auxiliary valve of each battery module;

[0119] 12, recovery tank communication liquid inlet valve; 12P, positive electrode recovery tank communication liquid inlet valve; 12N, negative electrode recovery tank communication liquid inlet valve; 12PA, positive electrode recovery tank communication liquid inlet valve of battery module A; 12NA, negative electrode recovery tank communication liquid inlet valve of battery module A; 12PB, positive electrode recovery tank communication liquid inlet valve of battery module B; 12NB, negative electrode recovery tank communication liquid inlet valve of battery module B;

[0120] 13, recovery tank communication liquid outlet valve; 13P, positive electrode recovery tank communication liquid outlet valve; 13N, negative electrode recovery tank communication liquid outlet valve;

[0121] 14, mixed liquid balancing valve of each battery module;

[0122] 15, recovery tank liquid outlet valve; 15P, positive electrode recovery tank liquid outlet valve; 15N, negative electrode recovery tank liquid outlet valve;

[0123] 16, recovery tank liquid return valve; 16P, positive electrode recovery tank liquid return valve; 16N, negative electrode recovery tank liquid return valve;

[0124] 17, nitrogen valve;

[0125] 18, tank body gas inlet valve of each battery module; 18P, positive electrode tank body gas inlet valve of each battery module; 18N, negative electrode tank body gas inlet valve of each battery module; 18PA, positive electrode tank body gas inlet valve of battery module A; 18NA, negative electrode tank body gas inlet valve of battery module A; 18PB, positive electrode tank body gas inlet valve of battery module B; 18NB, negative electrode tank body gas inlet valve of battery module B;

[0126] 19, tank body gas outlet valve of each battery module; 19P, positive electrode tank body gas outlet valve of each battery module; 19N, negative electrode tank body gas outlet valve of each battery module; 19PA, positive electrode tank body gas outlet valve of battery module A; 19NA, negative electrode tank body gas outlet valve of battery module A; 19PB, positive electrode tank body gas outlet valve of battery module B; 19NB, negative electrode tank body gas outlet valve of battery module B;

[0127] 20, tank body intake valve of recovery tank; 20P, positive tank body intake valve of recovery tank; 20N, negative tank body intake valve of recovery tank;

[0128] 21, tank body outlet valve of recovery tank; 21P, positive tank body outlet valve of recovery tank; 21N, negative tank body outlet valve of recovery tank;

[0129] 22, stack intake sensor group of each battery module; 22P, positive stack intake sensor group of each battery module; 22N, negative stack intake sensor group of each battery module; 221PA, positive stack intake temperature sensor of battery module A; 221NA, negative stack intake temperature sensor of battery module A; 221PB, positive stack intake temperature sensor of battery module B; 221NB, negative stack intake temperature sensor of battery module B; 222PA, positive stack intake voltage sensor of battery module A; 222NA, negative stack intake voltage sensor of battery module A; 222PB, positive stack intake voltage sensor of battery module B; 222NB, negative stack intake voltage sensor of battery module B;

[0130] 23, stack outlet sensor group of each battery module; 23P, positive stack outlet sensor group of each battery module; 23N, negative stack outlet sensor group of each battery module; 231PA, positive stack outlet temperature sensor of battery module A; 231NA, negative stack outlet temperature sensor of battery module A; 231PB, positive stack outlet temperature sensor of battery module B; 231NB, negative stack outlet temperature sensor of battery module B; 232PA, positive stack outlet voltage sensor of battery module A; 232NA, negative stack outlet voltage sensor of battery module A; 232PB, positive stack outlet voltage sensor of battery module B; 232NB, negative stack outlet voltage sensor of battery module B; 233PA, positive stack outlet flow sensor of battery module A; 233NA, negative stack outlet flow sensor of battery module A; 233PB, positive stack outlet flow sensor of battery module B; 233NB, negative stack outlet flow sensor of battery module B;

[0131] 24, can sensor group of each battery module; 24P, positive can sensor group of each battery module; 24N, negative can sensor group of each battery module; 241PA, positive can liquid pressure sensor of battery module A; 241NA, negative can liquid pressure sensor of battery module A; 241PB, positive can liquid pressure sensor of battery module B; 241NB, negative can liquid pressure sensor of battery module B; 242PA, positive can gas pressure sensor of battery module A; 242NA, negative can gas pressure sensor of battery module A; 242PB, positive can gas pressure sensor of battery module B; 242NB, negative can gas pressure sensor of battery module B;

[0132] 25, direct current energy meter of each battery module;

[0133] 26, recovery can in-stack sensor group; 26P, positive recovery can in-stack sensor group; 26N, negative recovery can in-stack sensor group; 261P, positive recovery can in-stack temperature sensor; 261N, negative recovery can in-stack temperature sensor; 262P, positive recovery can in-stack voltage sensor; 262N, negative recovery can in-stack voltage sensor;

[0134] 27, recovery can out-stack sensor group; 27P, positive recovery can out-stack sensor group; 27N, negative recovery can out-stack sensor group; 271P, positive recovery can out-stack temperature sensor; 271N, negative recovery can out-stack temperature sensor; 272P, positive recovery can out-stack flow sensor; 272N, negative recovery can out-stack flow sensor;

[0135] 28, recovery can can sensor group; 281, recovery can can liquid pressure sensor; 282, recovery can can gas pressure sensor;

[0136] 29, auxiliary positive can can sensor group; 291, auxiliary positive can can liquid pressure sensor; 292, auxiliary positive can can gas pressure sensor;

[0137] 30, battery management system. DETAILED DESCRIPTION

[0138] The following will be described in detail below with reference to the accompanying drawings. Figures 1-7 The present application is further described in detail.

[0139] In order to make the purposes, technical solutions and advantages of the patent embodiments clearer, the technical solutions in the patent embodiments will be clearly and completely explained in combination with the drawings in the patent embodiments. Obviously, the described embodiments are a part of the embodiments of the patent, rather than all the embodiments. Based on the embodiments in the patent, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the protection scope of the patent.

[0140] Figure 1 The figure is a whole system relationship diagram of the patent embodiments. As shown in the figure, a control device for total amount balance of electrolyte of a flow battery includes an energy storage system, an exhaust system, a flow battery health recovery system and a battery management system. The energy storage system includes a plurality of sub-cell modules. Figure 1

[0141] Figure 2 The figure is a schematic diagram of a whole system pipeline structure. The connection mode of each component in the system is shown in the figure. Refer to Figure 2 The installation position of each component should meet the following requirements:

[0142] The energy storage system structure refers to Figure 2 and Figure 5 ​The electrolyte pipeline of the battery module A starts from the positive electrolyte tank 01PA and the negative electrolyte tank 01NA of the battery module A, passes through the liquid outlet pipe of the battery module A, and sequentially passes through the positive liquid outlet valve 09P and the negative liquid outlet valve 09N of the battery module A, the positive liquid flow pump 07PA and the negative liquid flow pump 07NA of the battery module A, the positive stack inlet sensor group 22P and the negative stack inlet sensor group 22N of the battery module A, and then reaches the stack group 05A of the battery module A. There is a pipeline branch between the positive liquid outlet valve 09P and the positive liquid flow pump 07PA of the battery module A, so that the positive liquid supply pipe is connected to one side of the mixed liquid balance valve 14 of the battery module A. Similarly, there is a pipeline branch between the negative liquid outlet valve 09N and the negative liquid flow pump 07N of the battery module A, so that the negative liquid supply pipe is connected to the other side of the mixed liquid balance valve 14 of the battery module A. Then, the liquid is returned from the stack group 05A of the battery module A, passes through the positive stack outlet sensor group 23P and the negative stack outlet sensor group 23N of each battery module of the battery module A, the positive liquid return valve 10P and the negative liquid return valve 10N of each battery module, and returns to the positive electrolyte tank 01PA and the negative electrolyte tank 01NA of the battery module A via the liquid return pipe of the battery module A. The liquid outlet pipe and the liquid return pipe are connected through the positive bypass auxiliary valve 11P and the negative bypass auxiliary valve 11N of the battery module A via a small circulation pipeline. The liquid outlet pipe starts from the positive electrolyte tank 01PA and the negative electrolyte tank 01NA of the battery module A, is connected to the recovery tank liquid inlet pipe of the liquid flow battery recovery system via a branch, and the recovery tank liquid outlet pipe of the liquid flow battery recovery system is connected to the liquid return pipe, and then returns to the positive electrolyte tank 01P and the negative electrolyte tank 01N of the battery module A. An overflow pipe is drawn out from the positive electrolyte tank 01P and the negative electrolyte tank 01N of the battery module A, and is connected to the recovery tank liquid inlet pipe of the liquid flow battery recovery system.The positive electrode liquid storage tank 01P of the battery module A and the negative electrode liquid storage tank 01N of the battery module A are provided with the positive electrode tank body sensor group 24P of the battery module A and the negative electrode tank body sensor group 24N of the battery module A; the positive electrode stack inlet sensor group 22P of the battery module A includes the positive electrode stack inlet temperature sensor 221PA of the battery module A and the positive electrode stack inlet voltage sensor 222PA of the battery module A; the negative electrode stack inlet sensor group 22N of the battery module A includes the negative electrode stack inlet temperature sensor 221NA of the battery module A and the negative electrode stack inlet voltage sensor 222NA of the battery module A; the positive electrode stack outlet sensor group 23P of the battery module A includes the positive electrode stack outlet temperature sensor 231PA of the battery module A, the positive electrode stack outlet voltage sensor 232PA of the battery module A and the positive electrode stack outlet flow sensor 233PA of the battery module A; the negative electrode stack outlet sensor group 23N of the battery module A includes the negative electrode stack outlet temperature sensor 231NA of the battery module A, the negative electrode stack outlet voltage sensor 232NA of the battery module A and the negative electrode stack outlet flow sensor 233NA of the battery module A; the positive electrode tank body sensor group 24P of the battery module A includes the positive electrode tank body liquid pressure sensor 241PA of the battery module A and the positive electrode tank body gas pressure sensor 242PA of the battery module A; the negative electrode tank body sensor group 24N of the battery module A includes the negative electrode tank body liquid pressure sensor 241NA of the battery module A and the negative electrode tank body gas pressure sensor 242NA of the battery module A; the battery module B is equivalent.

[0143] Redox flow battery health recovery system structure Figure 2 、 Figure 3 With Figure 6: electrolyte pipeline from the comprehensive SOH recovery tank 02 and auxiliary positive tank 03, respectively, via the reduction of liquid pipe, in turn, through the positive recovery tank liquid valve 15P and negative recovery tank liquid valve 15N, positive balance liquid flow pump 08P and negative balance liquid flow pump 08N, recovery tank positive into the stack sensor group 26P and recovery tank negative into the stack sensor group 26N into the auxiliary stack group 06; again from the auxiliary stack group 06, via the reduction of liquid pipe, in turn, through the recovery tank out of the stack sensor group 27, recovery tank liquid valve 16, according to its polarity, respectively, back to the comprehensive SOH recovery tank 02 and auxiliary positive tank 03. In addition, there is a branch of electrolyte pipeline from the comprehensive SOH recovery tank 02, via the recovery tank communication liquid valve 13, respectively, through a branch of each battery module of a liquid pipe, and each battery module in the energy storage system is connected; finally, again by a branch of each battery module of a liquid pipe is gathered, through the recovery tank communication liquid valve 12, back to the comprehensive SOH recovery tank 02. The comprehensive SOH recovery tank 02 is provided with a recovery tank body sensor group 28; the auxiliary positive tank 03 is provided with an auxiliary positive tank body sensor group 29; the direct current side of the circuit of the stack group 05 of each battery module is provided with a direct current electric energy meter 25 of each battery module. The recovery tank into the stack sensor group 26 includes a recovery tank into the stack temperature sensor 261 and a recovery tank into the stack voltage sensor 262; the recovery tank out of the stack sensor group 27 includes a recovery tank out of the stack temperature sensor 271 and a recovery tank out of the stack flow sensor 272; the recovery tank body sensor group 28 includes a recovery tank body liquid pressure sensor 281 and a recovery tank body gas pressure sensor 282; the auxiliary positive tank body sensor group includes an auxiliary positive tank body liquid pressure sensor 291 and an auxiliary positive tank body gas pressure sensor 292.

[0144] Exhaust system structure refers to Figure 2 With Figure 4 : nitrogen pipeline from the nitrogen tank 04, via the gas inlet pipeline, after flowing through the nitrogen valve 17, respectively, via the tank body gas inlet valve 18 of each battery module and the liquid storage tank 01 of each battery module, that is, connected with the energy storage system, then a gas outlet pipeline is led out from the liquid storage tank 01 of each battery module, connected with the gas recovery device via the tank body gas outlet valve 19 of each battery module; at the same time, the gas inlet pipeline is connected with the tank body gas inlet valve 20 of the recovery tank, the comprehensive SOH recovery tank 02 / auxiliary positive tank 03, that is, connected with the liquid flow battery health recovery system, via a branch after the nitrogen valve 17; finally, via a gas outlet pipeline, the comprehensive SOH recovery tank 02 / auxiliary positive tank 03 is connected with the gas recovery device via the tank body gas outlet valve 21 of the recovery tank.

[0145] A control device for SOH recovery of liquid flow battery, when each battery module performs SOH calculation, the following method can be used:

[0146] The open circuit voltage of the stack after the stack is at rest and not charging or discharging can be calculated using the stack inlet voltage sensor 222. Since the open circuit voltage is positively correlated with the system SOC, the relationship between the open circuit voltage and the SOC of the current power station can be obtained according to the characteristics of the current power station. At this time, the SOC values of each battery module at the start of the system can be obtained according to the data of the stack inlet voltage sensor 222. Taking battery module A as an example:

[0147] (1)

[0148] In the formula: SOC 1A is the initial SOC value of the first calibration of battery module A; U 222PA is the positive electrode stack inlet voltage measured by the positive electrode stack inlet voltage sensor 222PA of battery module A; U 222NA is the negative electrode stack inlet voltage measured by the negative electrode stack inlet voltage sensor 222NA of battery module A. At this time, according to the readings of the DC energy meter of each battery module, the charging energy E i1 and the discharging energy E o1 in the first calibration charging and discharging cycle are recorded.

[0149] After completing a single charging or discharging cycle for calibration, at the start of the next charging and discharging cycle for calibration, the above steps are repeated to record the initial SOC value SOC 2A , the charging energy E i2 and the discharging energy E o2 in the second calibration charging and discharging cycle at this time; then it is repeated again to record the initial SOC value SOC 3A of the third calibration charging and discharging cycle at this time; according to the obtained data, the calibration charging energy k 1p when the SOC of the battery module increases by 1% at the rated power and the calibration discharging energy k 2p when the SOC of the battery module decreases by 1% can be calculated. Wherein:

[0150] (2)

[0151] From the above formula, we can get:

[0152] (3)

[0153] The charging and discharging power of the battery module to be tested is adjusted to 90%, 80%, 70%, 60%, 50%, and 40% of the rated power, respectively. According to the characteristics of the current power station, the mapping relationship between the calibration charging energy k1 when the SOC of the battery module to be tested increases by 1% and the calibration discharging energy k2 when the SOC of the battery module to be tested decreases by 1% and the charging and discharging power P can be obtained:

[0154] (4)

[0155] The actual SOC value SOCactual in actual operation is obtained by the method R is:

[0156] (5)

[0157] In the formula, SOCactual is the actual SOC of the battery module A; SOCstart is the SOC of the battery module A at the current system start; Echarge is the charging energy value of the battery module A in the current operation cycle; E RA discharge is the discharging energy value of the battery module A in the current operation cycle. In addition, the SOC calculation of other battery modules and the SOC of the flow battery health recovery system are all calculated according to the formula. 0A iA oA At the rated power, the discharging energy k of the power when the SOC of the battery module to be tested decreases by 1% is recorded 2E , and the calibration value at the rated power is recorded as k 2P . During operation, the SOH of the battery module can be recorded as:

[0158]

[0159] (6)

[0160] In combination with the mapping relationship of the calibration charging energy k1 of the battery module to be tested when the SOC increases by 1%, the calibration discharging energy k2 of the battery module to be tested when the SOC decreases by 1%, and the charging and discharging power P in formula (4), the current system SOH value can be calculated at any power by using the discharging energy k2 of the current battery module to be tested when the SOC decreases by 1% at the actual discharging power and the discharging power P:

[0161] (7)

[0162] During the operation of the system, the SOH recovery limit SOHlimit of the system can be set as 75%. When the SOH of a certain battery module during operation is less than SOHlimit, and the SOH of other battery modules is not lower than SOHlimit, the liquid outlet valve and the liquid mixing balance valve of the battery module can be opened after the current operation ends, so that the positive and negative electrodes of the battery module are mixed, thereby performing certain self-recovery on the battery module. re re re

[0163] When the SOH of multiple battery modules during operation is less than SOHlimit, and the SOH of other battery modules is not lower than SOHlimit, the liquid outlet valve and the liquid mixing balance valve of the battery module can be opened after the current operation ends, so that the positive and negative electrodes of the battery module are mixed, thereby performing certain self-recovery on the battery module. re ​​​​​​At this time, the whole system should be mixed and restored after the end of this operation. At this time, the recovery tank connecting liquid inlet valve and the recovery tank connecting liquid outlet valve should be opened; after the completion of the whole blending, the recovery tank connecting liquid inlet valve and the recovery tank connecting liquid outlet valve should be closed, the recovery tank liquid outlet valve and the recovery tank liquid return valve should be opened, and the reducing charging of the liquid flow battery health recovery system is started; during the charging process, the open circuit voltage SOC value corresponding to the recovery tank stack voltage of the current liquid flow battery health recovery system is calculated by using the voltage difference of the recovery tank stack voltage and the correlation formula of the open circuit voltage and SOC obtained before. h ;

[0164] (8)

[0165] In the formula: U 262P is the voltage value measured by the recovery tank positive electrode stack voltage sensor 262P; U 262N is the voltage value measured by the recovery tank negative electrode stack voltage sensor 262N.

[0166] After the charging is continued, the charging is ended after the SOC h is 60%. After the charging is completed, the recovery tank connecting liquid inlet valve and the recovery tank connecting liquid outlet valve are opened again, the reduced electrolyte is mixed with the electrolyte in the original system, and after the mixing is completed, the recovery tank connecting liquid inlet valve and the recovery tank connecting liquid outlet valve are closed. At this time, the recovery of SOH is completed.

[0167] In the following, several embodiments will be used to specifically describe the embodiments.

[0168] Embodiment 1

[0169] In one embodiment, an apparatus for liquid flow battery SOH calculation and recovery includes an energy storage system, an exhaust system, a liquid flow battery health recovery system, and a battery management system. The energy storage system includes three sub-battery modules, which are battery module A, battery module B, and battery module C. In the embodiment, the system SOH recovery limit SOH re is 75%, and the rated power is 500 kW. During the calibration process, the SOC value is calculated by using the mapping relationship between the open circuit voltage and the SOC.

[0170] In the first calibrated charge and discharge cycle: the initial SOC value SOC1 is 20%, the charging electric energy E i1 is 460 kWh, and the discharging electric energy E o1 is 0 kWh.

[0171] In the second calibrated charge and discharge cycle: the initial SOC value SOC2 is 76.8%, the charging electric energy E i2 is 0 kWh, and the discharging electric energy E o2 is 344 kWh.

[0172] The third calibration charge and discharge cycle: the initial SOC value SOC3 is 19.3%;

[0173] Substituting formula (2) in the above embodiment, the calibrated charging power k1 for each 1% increase of the battery module SOC can be solved as 8.0986 kWh; and the calibrated discharging power k2 for each 1% decrease of the battery module SOC can be solved as 5.9826 kWh. 1p 2p

[0174] The mapping relationship between the SOH and the discharging power k2 for each 1% decrease of the battery module SOC and the operating power P of the battery module in this embodiment is as follows:

[0175] (9)

[0176] In the formula, the parameters b0, b1 and b2 are undetermined coefficients obtained in the calibration process. Through repeated calibration at 90%, 80%, 70%, 60%, 50% and 40% of the rated power, the parameters b0, b1 and b2 in the mapping relationship between the SOH of the flow battery system and the discharging power k2 for each 1% decrease of the battery module SOC and the operating power P of the battery module can be obtained, so that the real-time SOH of the system can be obtained during operation.

[0177] Embodiment 2

[0178] In one embodiment, an apparatus for flow battery SOH calculation and recovery includes an energy storage system, an exhaust system, a flow battery health recovery system, and a battery management system. The energy storage system includes three sub-battery modules, which are denoted as battery module A, battery module B and battery module C. In this embodiment, the system SOH recovery limit SOH re is set to 75%, and the rated power is 500 kW.

[0179] During a certain operation process, the SOH of each battery module is measured using the method in the above embodiment. Among them: the SOH value SOH A of battery module A in this operation is 73%; the SOH value SOH B of battery module B in this operation is 78%; and the SOH value SOH C of battery module C in this operation is 76%. The system determines that battery module A needs to be separately blended with electrolyte.

[0180] In this embodiment, the electrolyte blending process of battery module A is as follows:

[0181] ​​The positive liquid outlet valve 09P of the battery module A and the negative liquid outlet valve 09N of the battery module A are opened, and then the mixed liquid balance valve 14 of the battery module A is opened to mix the positive and negative electrolytes; during the mixing process, the nitrogen valve 17, the negative tank inlet valve 18NA of the battery module A and the negative tank outlet valve 19NA of the battery module A are opened, and the nitrogen gas in the nitrogen tank 04 is filled into the negative liquid storage tank 01NA. In this embodiment, the negative liquid storage tank needs to maintain a positive pressure of 8 MPa to 10 MPa, so that the electrolyte flows from the negative electrode to the positive electrode, and the byproduct gas is discharged into the gas recovery device. When the liquid level difference between the positive liquid storage tank 01PA and the negative liquid storage tank 01NA reaches 10 cm, the negative tank inlet valve 18NA of the battery module A is closed, the positive tank inlet valve 18PA of the battery module A is opened, the nitrogen gas in the nitrogen tank 04 is filled into the positive liquid storage tank 01PA, and the positive liquid storage tank is maintained at a positive pressure of 3 MPa to 5 MPa, so that the electrolyte flows from the positive electrode to the negative electrode, and the byproduct gas is discharged into the gas recovery device, until the electrolytes in the two liquid storage tanks are balanced. Repeat this process 3 times to achieve the effect of SOH recovery by blending.

[0182] Embodiment 3

[0183] In one embodiment, an apparatus for liquid flow battery SOH calculation and recovery, the structure includes an energy storage system, an exhaust system, a liquid flow battery health recovery system, and a battery management system. The energy storage system includes two sub-battery modules, which are battery module A and battery module B. In the embodiment, the system SOH recovery limit SOH re is 75%, and the rated power is 500 kW.

[0184] During a certain operation process, the SOH of each battery module is measured using the method in the above embodiment. Among them: the SOH value SOH A of the battery module A in this operation is 71%; the SOH value SOH B of the battery module B in this operation is 72%. It is determined that the electrolyte blending of the whole system is needed.

[0185] In this embodiment, the electrolyte blending process of the system is as follows:

[0186] Open the recovery tank positive communication inlet valve 12PA of the battery module A, the recovery tank negative communication inlet valve 12NA of the battery module A, the recovery tank positive communication inlet valve 12PB of the battery module B, the recovery tank negative communication inlet valve 12NB of the battery module B, and inject the electrolyte in the positive electrolyte tank 01PA of the battery module A, the negative electrolyte tank 01NA of the battery module A, the positive electrolyte tank 01PB of the battery module B, and the negative electrolyte tank 01NB of the battery module B into the comprehensive SOH recovery tank 02 until the liquid level in the comprehensive SOH recovery tank 02 and the auxiliary positive tank 03 reaches balance. During the injection process, the positive tank body inlet valve 18PA of the battery module A, the negative tank body inlet valve 18NA of the battery module A, the positive tank body inlet valve 18PB of the battery module B, the negative tank body inlet valve 18NB of the battery module B, the negative tank body outlet valve 21N of the recovery tank, and the nitrogen valve 17 should be opened, and the nitrogen in the nitrogen tank 04 is filled into the positive electrolyte tank 01PA of the battery module A, the negative electrolyte tank 01NA of the battery module A, the positive electrolyte tank 01PB of the battery module B, and the negative electrolyte tank 01NB of the battery module B, so that the electrolyte tank maintains a positive pressure of 3MPa-5MPa, and until the electrolyte liquid level in the comprehensive SOH recovery tank 02 reaches 80% in the auxiliary positive tank 03, then the above-mentioned valves are closed until the injection is completed.

[0187] After the injection is completed, the recovery tank positive communication inlet valve 12PA of the battery module A, the recovery tank negative communication inlet valve 12NA of the battery module A, the recovery tank positive communication inlet valve 12PB of the battery module B, and the recovery tank negative communication inlet valve 12NB of the battery module B are closed, and the flow battery health recovery system is charged until the SOC of the flow battery health recovery system reaches 60%.

[0188] After the charging is completed, the recovery tank positive communication inlet valve 12PA of the battery module A, the recovery tank negative communication inlet valve 12NA of the battery module A, the recovery tank positive communication inlet valve 12PB of the battery module B, and the recovery tank negative communication inlet valve 12NB of the battery module B are opened again, the negative tank body inlet valve 20N of the recovery tank, the negative tank body outlet valve 19NA of the battery module A, the negative tank body outlet valve 19NB of the battery module B, and the nitrogen valve 17 are opened, and the nitrogen in the nitrogen tank 04 is filled into the comprehensive SOH recovery tank 02 in the flow battery health recovery system until the electrolyte in the comprehensive SOH recovery tank 02 is discharged into the positive electrolyte tank 01PA of the battery module A, the negative electrolyte tank 01NA of the battery module A, the positive electrolyte tank 01PB of the battery module B, and the negative electrolyte tank 01NB of the battery module B, and mixed with the electrolyte in each electrolyte tank, so as to achieve the purpose of recovering the SOH of each battery module.

[0189] The above are all preferred embodiments of the present application, and do not limit the protection scope of the present application, so that: all equivalent changes made according to the structure, shape, principle of the present application should be covered in the protection scope of the present application.

Claims

1. A method for health state assessment recovery of a flow battery system, characterized in that, The application is applied to a flow battery including an energy storage system, the energy storage system at least includes one battery module, and the method includes: At different powers, the initial open circuit voltage, the initial charging electric energy and the initial discharging electric energy of the battery module stack after standing for different charging and discharging cycles are detected, and the initial state of charge value matched with the initial open circuit voltage is determined; Based on the initial state of charge value, the initial charging electric energy and the initial discharging electric energy, the calibrated unit charging electric energy and the calibrated unit discharging electric energy corresponding to the change of the state of charge by a preset threshold value are determined, and a first mapping relationship for representing the different charging powers and the calibrated unit charging electric energy and a second mapping relationship for representing the different discharging powers and the calibrated unit discharging electric energy are constructed; Based on the first mapping relationship and the second mapping relationship, the actual state of charge value in actual operation is determined, and the actual unit discharging electric energy corresponding to the change of the actual state of charge value by a preset threshold value is determined; The unit discharging electric energy corresponding to the actual discharging power is obtained from the second mapping relationship, and the health state evaluation value corresponding to the battery module is determined according to the actual unit discharging electric energy and the actual discharging power, so that the health state of the flow battery is evaluated and recovered through the health state evaluation value.

2. The method of claim 1, wherein, The initial open circuit voltage, the initial charging electric energy and the initial discharging electric energy of the battery module stack after standing for different charging and discharging cycles are detected at different powers, and the initial state of charge value matched with the initial open circuit voltage is determined, including: For any power, the initial open circuit voltage, the initial charging electric energy and the initial discharging electric energy of the battery module stack after standing are detected according to a preset charging and discharging cycle; wherein the preset charging and discharging cycle at least includes a first cycle for first charging, a second cycle for discharging and a third cycle for second charging; The initial state of charge value matched with the initial open circuit voltage is determined through the preset correspondence between the state of charge and the open circuit voltage.

3. The method of claim 1, wherein, Based on the initial state of charge value, the initial charging electric energy and the initial discharging electric energy, the calibrated unit charging electric energy and the calibrated unit discharging electric energy corresponding to the change of the state of charge by a preset threshold value are determined, including: Based on the initial state of charge value, the change amount of the state of charge in each charging and discharging cycle is determined; A matrix containing the initial charging electric energy and the initial discharging electric energy is constructed, and a vector containing the initial charging electric energy, the initial discharging electric energy and the change amount of the state of charge is constructed; The calibrated unit charging electric energy corresponding to the increase of the state of charge by the preset threshold value is determined, and the calibrated unit discharging electric energy corresponding to the decrease of the state of charge by the preset threshold value is determined by using the matrix and the vector.

4. The method of claim 1, wherein, Based on the first mapping relationship and the second mapping relationship, the actual state of charge value in actual operation is determined, including: At the current power, the initial charge state value when the battery module starts is obtained; and the current charging power and the current discharging power of the battery module in actual operation are obtained; According to the current charging power and the current discharging power of the battery module, the calibrated unit charging electric energy and the calibrated unit discharging electric energy under the current power are found from the first mapping relationship and the second mapping relationship; The initial state of charge value, the current charging electric energy, the current discharging electric energy, the calibrated unit charging electric energy under the current power and the calibrated unit discharging electric energy under the current power are used to determine the actual state of charge value in actual operation.

5. The method of claim 1, wherein, The unit discharging electric energy corresponding to the actual discharging power is obtained from the second mapping relationship, and the health state evaluation value corresponding to the battery module is determined according to the unit discharging electric energy and the actual discharging power, including: The unit discharging electric energy corresponding to the actual discharging power is obtained from the second mapping relationship; The ratio between the rated unit discharging electric energy and the calibrated rated unit discharging electric energy is determined; The ratio is determined as the health state evaluation value corresponding to the battery module.

6. The method of claim 1, wherein, The health state of the flow battery is evaluated and recovered through the health state evaluation value, including: Only when the health state evaluation value of one battery module is less than a preset evaluation threshold, the positive and negative electrolyte of the battery module less than the preset evaluation threshold is mixed uniformly after the operation ends, so as to recover the flow battery; When the health state evaluation values of at least two battery modules are less than the preset evaluation threshold, the positive and negative electrolyte of all battery modules is mixed uniformly after the operation ends, so as to recover the flow battery.

7. An apparatus for implementing the method of any one of claims 1-6, wherein the apparatus comprises: The device includes an energy storage system, an exhaust system, a flow battery health recovery system and a battery management system (30); wherein, The energy storage system is used for storing and releasing electric energy, and the energy storage system includes a plurality of sub-battery modules, including a liquid storage tank (01) of each battery module, a stack group (05) of each battery module, a liquid flow pump (07) of each battery module, an outlet valve (09) of each battery module, a return valve (10) of each battery module, a bypass auxiliary valve (11) of each battery module, a liquid mixing balance valve (14) of each battery module, an inlet stack sensor group (22) of each battery module, an outlet stack sensor group (23) of each battery module, a tank sensor group (24) of each battery module and a direct current electric energy meter (25) of each battery module; The exhaust system is used for collecting and discharging the by-product gas generated by the system, including a nitrogen tank (04), a nitrogen valve (17), a tank inlet valve (18) of each battery module, a tank outlet valve (19) of each battery module, a tank inlet valve (20) of a recovery tank and a tank outlet valve (21) of the recovery tank; The exhaust system is used for collecting and discharging the by-product gas generated by the system, including a nitrogen tank (04), a nitrogen valve (17), a tank inlet valve (18) of each battery module, a tank outlet valve (19) of each battery module, a tank inlet valve (20) of a recovery tank and a tank outlet valve (21) of the recovery tank; The liquid flow battery health recovery system is used for recovering the health state of the liquid flow battery, and comprises a comprehensive SOH recovery tank (02), an auxiliary positive electrode tank (03), an auxiliary stack group (06), a balance liquid flow pump (08), a recovery tank connection liquid inlet valve (12), a recovery tank connection liquid outlet valve (13), a recovery tank liquid outlet valve (15), a recovery tank liquid return valve (16), a recovery tank stack inlet sensor group (26), a recovery tank stack outlet sensor group (27), a recovery tank tank body sensor group (28), and an auxiliary positive electrode tank tank body sensor group (29). The battery management system (30) is used for integrating the energy storage system, the exhaust system, and the liquid flow battery health recovery system.

8. The apparatus of claim 7, wherein: The liquid outlet valve (09) of each battery module is arranged between the liquid storage tank (01) of each battery module and the stack group (05) of each battery module; There is a pipeline branch between the liquid outlet valve (09) of each battery module and the liquid storage tank (01) of each battery module, and between the liquid outlet valve (09) of each battery module and the stack group (05) of each battery module; The pipeline branch between the liquid outlet valve (09) of each battery module and the liquid storage tank (01) of each battery module is connected with the energy storage system and the liquid flow battery health recovery system; The pipeline branch between the liquid outlet valve (09) of each battery module and the stack group (05) of each battery module is sequentially provided with the liquid flow pump (07) of each battery module and the stack inlet sensor group (22) of each battery module; The stack inlet sensor group of each battery module comprises a stack inlet temperature sensor (221) and a stack inlet voltage sensor (222); The mixed liquid balance valve (14) of each battery module is arranged between the pipeline branch between the liquid outlet valve (09) of each battery module and the stack group (05) of each battery module and the positive electrode and the negative electrode; The liquid return valve (10) of each battery module is arranged between the stack group (05) of each battery module and the liquid storage tank (01) of each battery module; The liquid return valve (10) of each battery module is provided with the stack outlet sensor group (23) of each battery module between the stack group (05) of each battery module and the liquid storage tank (01) of each battery module; The stack outlet sensor group of each battery module comprises a stack outlet temperature sensor (231), a stack outlet voltage sensor (232), and a stack outlet flow sensor (233); There is a pipeline branch between the liquid return valve (10) of each battery module and the liquid storage tank (01) of each battery module; The pipeline branch between the liquid return valve (10) of each battery module and the liquid storage tank (01) of each battery module is connected with the energy storage system and the liquid flow battery health recovery system; The bypass auxiliary valve (11) of each battery module is arranged between the branch and the pipeline branch between the liquid outlet valve (09) of each battery module and the liquid storage tank (01) of each battery module; The liquid storage tank (01) of each battery module is provided with the tank body sensor group (24) of each battery module; The tank body sensor group of each battery module comprises a tank body liquid pressure sensor (241) and a tank body gas pressure sensor (242).

9. The apparatus of claim 7, wherein: The recovery tank connecting liquid inlet valve (12) is arranged between the liquid outlet valve (09) of each battery module in the energy storage system and the tank (01) of each battery module and the branch pipeline and the comprehensive SOH recovery tank (02); The recovery tank connecting liquid inlet valve (12) is arranged between the liquid outlet valve (09) of each battery module in the energy storage system and the tank (01) of each battery module and the branch pipeline and the comprehensive SOH recovery tank (02); The recovery tank connecting liquid inlet valve (12) is arranged between the liquid outlet valve (09) of each battery module in the energy storage system and the tank (01) of each battery module and the branch pipeline and the comprehensive SOH recovery tank (02); The recovery tank connecting liquid inlet valve (12) is arranged between the liquid outlet valve (09) of each battery module in the energy storage system and the tank (01) of each battery module and the branch pipeline and the comprehensive SOH recovery tank (02); The recovery tank connecting liquid inlet valve (12) is arranged between the liquid outlet valve (09) of each battery module in the energy storage system and the tank (01) of each battery module and the branch pipeline and the comprehensive SOH recovery tank (02); The recovery tank connecting liquid inlet valve (12) is arranged between the liquid outlet valve (09) of each battery module in the energy storage system and the tank (01) of each battery module and the branch pipeline and the comprehensive SOH recovery tank (02); The recovery tank connecting liquid inlet valve (12) is arranged between the liquid outlet valve (09) of each battery module in the energy storage system and the tank (01) of each battery module and the branch pipeline and the comprehensive SOH recovery tank (02); The recovery tank connecting liquid inlet valve (12) is arranged between the liquid outlet valve (09) of each battery module in the energy storage system and the tank (01) of each battery module and the branch pipeline and the comprehensive SOH recovery tank (02); The recovery tank connecting liquid inlet valve (12) is arranged between the liquid outlet valve (09) of each battery module in the energy storage system and the tank (01) of each battery module and the branch pipeline and the comprehensive SOH recovery tank (02); The recovery tank connecting liquid inlet valve (12) is arranged between the liquid outlet valve (09) of each battery module in the energy storage system and the tank (01) of each battery module and the branch pipeline and the comprehensive SOH recovery tank (02).

10. The device of claim 7, wherein The nitrogen valve (17) is arranged after the nitrogen tank (04); there is a branch pipeline after the nitrogen valve (17) and connected with the tank (01) of each battery module of the energy storage system and the comprehensive SOH recovery tank (02) of the liquid flow battery health recovery system respectively; The tank body gas inlet valve (18) of each battery module is arranged between the branch pipeline after the nitrogen valve (17) and the tank (01) of each battery module; The tank body gas outlet valve (19) of each battery module is arranged between the tank (01) of each battery module and the gas recovery device; The tank body gas inlet valve (20) of the recovery tank is arranged between the branch pipeline after the nitrogen valve (17) and the comprehensive SOH recovery tank (02) or the auxiliary positive tank (03); The tank body gas outlet valve (21) of the recovery tank is arranged between the comprehensive SOH recovery tank (02) or the auxiliary positive tank (03) and the gas recovery device. ​

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