Iron-chromium flow battery energy storage system

Abstract

The invention relates to the technical field of flow batteries, and discloses an iron-chromium flow battery energy storage system, which comprises a hydrogen resource regeneration unit, and the hydrogen resource regeneration unit comprises a hydrogen collection module, a built-in condensation demister and a palladium membrane purifier, wherein the hydrogen collection module is connected with an electric pile positive electrode exhaust port and a storage tank gas phase space; an anode inlet of the micro PEM electrolytic cell is connected with the purified hydrogen outlet, and a cathode inlet is connected with a deionized water source; the reinjection module comprises an acid liquid buffer tank and a metering pump, and a reinjection point is located on the positive electrode circulation pipeline; and the hydrogen evolution dynamic suppression unit comprises a charging and discharging regulator which responds to the hydrogen evolution rate signal to reduce the charging current or mark the surplus power. According to the energy storage system of the iron-chromium flow battery, hydrogen evolution gas is converted into hydrogen ions through the integrated miniature electrolytic cell, the hydrogen ions are accurately reinjected, a closed-loop regeneration system is constructed, the problem of chemical imbalance caused by hydrogen ion loss is solved, waste hydrogen is converted into system resources, the regeneration process is driven by surplus energy in the discharge process, and the overall energy efficiency is remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of flow battery technology, and more particularly to an iron-chromium flow battery energy storage system. Background Technology

[0002] Iron-chromium redox flow batteries, as a novel large-scale energy storage technology, have broad application prospects in renewable energy grid integration and grid peak shaving due to their advantages such as long cycle life, low electrolyte cost, and environmental friendliness. However, during the charging process of iron-chromium redox flow batteries, hydrogen ions in the positive electrode electrolyte are prone to hydrogen evolution side reactions, which not only reduce battery energy efficiency but also lead to hydrogen accumulation and potential safety hazards.

[0003] Currently, existing technologies mainly address the hydrogen evolution problem in two ways: one is passive suppression, which involves adding corrosion inhibitors or limiting hydrogen ion migration, but this cannot dynamically adapt to changes in charge and discharge conditions; the other is active collection, which involves collecting hydrogen through simple gas-liquid separation devices and then directly discharging or burning it, without realizing the resource utilization of hydrogen. Summary of the Invention

[0004] The technical problem to be solved by this invention is the chemical imbalance caused by hydrogen evolution byproducts generated by iron-chromium redox flow batteries. To address this, we propose an iron-chromium redox flow battery energy storage system.

[0005] To achieve the above objectives, this application adopts the following technical solution: an iron-chromium redox flow battery energy storage system, comprising: The hydrogen resource recycling unit includes: a hydrogen collection module, which connects the positive electrode exhaust port of the fuel cell stack to the gas phase space of the storage tank, and has a built-in condenser and demister and a palladium membrane purifier. The micro PEM electrolyzer has its anode inlet connected to the purified hydrogen outlet and its cathode inlet connected to a deionized water source. The reinjection module includes an acidic liquid buffer tank and a metering pump, with the reinjection point located in the positive electrode circulation pipeline; The hydrogen evolution dynamic suppression unit includes: a charge / discharge regulator that reduces the charging current or marks excess power in response to the hydrogen evolution rate signal; Dual-mode flow channel, which can switch between cross-dispersed flow channel and funnel-mouth concentrated flow channel; The cooperative control unit is configured to perform the following: when charging / discharging stops, activate the horn-mouth flow channel and pause it. Reinject for 200ms; once the flow stabilizes, initiate pulsed injection. Refill and activate the static mixer; Dynamically allocate electrolytic cell power according to the formula: ,in This refers to the output power of the electrolytic cell. The correlation coefficient for hydrogen generation rate ranges from 1.5 to 2.2. The hydrogen production rate, The correlation coefficient for pH changes ranges from 40 to 60. This represents the change in the pH value of the solution.

[0006] Preferably, the hydrogen resource regeneration unit further includes: a hydrogen circulation pipeline for outputting the cathode. Returned to the anode inlet of the electrolytic cell; The inert gas discharge valve opens every 24 hours to release 0.3-0.7% of the gas volume.

[0007] Preferably, the switching response time of the dual-mode flow channel is ≤150ms, and the opening cone angle of the horn-mouth flow channel is... .

[0008] Preferably, the anode catalyst of the PEM electrolyzer is composed of platinum, iridium, and a carbon support, with an iridium content ≥20wt%, and the membrane electrode is resistant to... Concentration ≥ 3%.

[0009] Preferably, the The execution logic of the injection module includes three levels of control: Feedforward control calculates the theoretical reinjection volume based on the hydrogen evolution rate. The calculation formula is as follows: Among them, the reinjection coefficient The range of values ​​is , Theoretical reinjection volume, The hydrogen production rate; Feedback control adjusts the metering pump frequency based on the pH sensor deviation; Safety limit: the amount of electrolyte injected in a single injection is ≤ 0.1% of the total electrolyte volume.

[0010] Preferably, when the charging / discharging stops, the collaborative control unit activates the horn-mouth flow channel with a time gradient of 100ms-150ms and simultaneously pauses the reinjection for 200ms±10ms. After the flow rate fluctuation in the positive electrode circulation pipeline is ≤5%, pulsed reinjection is initiated with a reinjection frequency of 0.8Hz-1.5Hz and a pulse width of 80ms-150ms. Simultaneously, the static mixer is activated, and the mixer speed and reinjection flow rate satisfy the following: ,in For rotational speed, This is for the reinjection flow.

[0011] Preferably, the hydrogen collection module removes water vapor from the hydrogen through the condensation temperature of the condenser demister and purifies it through a palladium membrane purifier. The purified hydrogen is then introduced into the anode of the micro PEM electrolyzer, and deionized water is introduced into the cathode of the electrolyzer. The electrolysis current density is controlled at 1A / cm²-3A / cm².

[0012] Preferably, when the hydrogen evolution rate is less than or equal to 0.2 L / h, the dual-mode flow channel switching operation switches to a cross-dispersion flow channel, and the residence time of the electrolyte in the flow channel is extended by 1.2-1.5 times; When the hydrogen evolution rate is greater than 0.2 L / h, switch to a funnel-shaped centralized flow channel, and increase the inlet flow velocity of the channel to 1.8-2.2 times the original flow velocity to quickly remove hydrogen.

[0013] Preferably, the formula for adjusting the charging current based on the hydrogen evolution rate signal by the charge / discharge regulator is as follows: ,in The adjusted charging current, This is the initial charging current. This is the attenuation coefficient, with a value ranging from 0.02 to 0.08. The hydrogen production rate is represented by .

[0014] Preferably, the system further includes a safety protection module, which comprises: an overpressure protection unit, an overtemperature protection unit, and a low liquid level protection unit; The overpressure protection unit automatically opens the inert gas discharge valve to relieve pressure when the pressure in the gas phase space of the storage tank is greater than 0.8 MPa. The over-temperature protection unit cuts off the power supply to the electrolytic cell and activates water cooling when the temperature of the micro PEM electrolytic cell exceeds 90°C. The low liquid protection unit triggers an audible and visual alarm and suspends refilling when the acidic liquid buffer tank level is less than 10%.

[0015] The technical effects and advantages of this invention are as follows: In this invention, hydrogen evolution gas is converted into hydrogen ions by an integrated micro-electrolyzer and precisely reinjected, constructing a closed-loop regeneration system. This solves the chemical imbalance problem caused by hydrogen ion loss and transforms waste hydrogen into system resources. The surplus energy from the discharge process drives the regeneration process, significantly improving overall energy efficiency. By combining the real-time adjustment of fluid patterns and flow rates with the charging and discharging status, and using neural network prediction to achieve preventative control, gas retention is effectively eliminated and the reaction environment is optimized. This fundamentally changes hydrogen evolution treatment, transforming waste into recyclable resources, maintaining chemical balance, and improving energy efficiency. Attached Figure Description

[0016] The disclosure of this invention is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. In the drawings, the same reference numerals are used to refer to the same parts: Figure 1 This is a flowchart of the iron-chromium redox flow battery energy storage system of the present invention; Figure 2 This is a flowchart of the hydrogen regeneration process of the present invention; Figure 3 This is a schematic diagram of the control signals of the present invention. Detailed Implementation

[0017] It is readily understood that, based on the technical solution of this invention, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of the invention. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solution of this invention and should not be considered as the entirety of the invention or as limitations or restrictions on the technical solution of this invention.

[0018] In existing technologies, iron-chromium redox flow batteries are prone to hydrogen evolution side reactions in the positive electrode electrolyte during charging, leading to hydrogen accumulation and electrolyte composition imbalance. Traditional solutions employ passive suppression or simple hydrogen collection and treatment, which suffer from problems such as hydrogen resource waste, unstable suppression effects, and insufficient system synergy. For example, fixed flow channel structures cannot adapt to dynamic operating conditions, and the lack of a linkage mechanism between the hydrogen treatment unit and the electrolyte control module can easily lead to safety hazards and efficiency degradation during long-term operation.

[0019] To solve the above problems, electrolytic regeneration is achieved. Closed-loop ion reinjection. Based on this, a technical route combining hydrogen collection and purification, electrolytic regeneration, dynamic flow channel switching, and coordinated control is proposed. First, a hydrogen resource regeneration unit is established to convert the collected hydrogen into an acidic electrolyte replenishment system; second, a dual-mode flow channel is designed to dynamically adjust the flow field morphology according to the hydrogen evolution rate; finally, a coordinated control unit is used to achieve time-series linkage and parameter matching of each module, forming a closed-loop control.

[0020] according to Figures 1-3 As shown, a Ferrochrome flow battery energy storage system is proposed, comprising a hydrogen collection module connecting the positive electrode exhaust port of the battery stack to the gas phase space of the storage tank. This module integrates a condenser / demister and a palladium membrane purifier, a micro PEM electrolyzer with its anode inlet connected to the purified hydrogen outlet and its cathode inlet connected to a deionized water source; a reinjection module including an acidic liquid buffer tank and a metering pump, with the reinjection point located in the positive electrode circulation pipeline; and a hydrogen evolution dynamic suppression unit including a charge / discharge regulator that responds to the hydrogen evolution rate signal. The charge / discharge regulator reduces the charging current or marks excess power in response to the hydrogen evolution rate signal. The formula for adjusting the charging current according to the hydrogen evolution rate signal is as follows: ,in The adjusted charging current, This is the initial charging current. This is the attenuation coefficient, with a value ranging from 0.02 to 0.08. The hydrogen production rate is represented by .

[0021] A dual-mode flow channel that switches between a cross-dispersed flow channel and a bell-mouth concentrated flow channel; a collaborative control unit configured to activate the bell-mouth flow channel and pause reinjection when charging and discharging stop, and to start pulse reinjection and activate the static mixer after the flow stabilizes, while dynamically distributing the electrolyzer power.

[0022] The hydrogen collection module removes water vapor from the hydrogen through a condenser demister at its condensation temperature and purifies it using a palladium membrane purifier. The purified hydrogen is then introduced into the anode of a micro PEM electrolyzer, while deionized water is introduced into the cathode. The electrolysis current density is controlled between 1A / cm² and 3A / cm². The hydrogen collection module is connected to the positive electrode exhaust port of the fuel cell stack and the gas phase space of the positive electrode storage tank via an acid-resistant pipe. When the fuel cell stack's state of charge (SOC) exceeds 70%, the mixed gas produced by the hydrogen evolution side reaction enters the hydrogen collection module. The condenser demister employs a spiral tube condensation structure for staged condensation, with the first stage being... The mixed gas enters the spiral tube condenser and demister. Under the condition of 5-10℃, it passes through the finned heat exchanger to remove droplets with a diameter >5μm. Then, it undergoes a second stage of condensation. The gas enters the 0-5℃ condensation section, which has a built-in stainless steel wire mesh demister with a mesh diameter of 0.1mm to remove droplets with a diameter >1μm and most of the water vapor. Finally, it undergoes a third stage of deep cooling. The gas enters the -5-0℃ coil-type deep cooler, where the dew point drops to below -20℃ and the residual water vapor content is ≤100ppm. The condensate is reinjected into the negative electrode storage tank through a fluororubber one-way valve.

[0023] A miniature PEM electrolyzer has its anode inlet connected to a purified hydrogen outlet and its cathode inlet connected to a deionized water source. The anode catalyst of the PEM electrolyzer is composed of platinum, iridium, and a carbon support, with an iridium content ≥20wt%, and the membrane electrode is resistant to... With a concentration ≥3%, platinum and iridium form an alloy structure on the carbon support surface. The high catalytic activity of platinum and the corrosion resistance of iridium produce a synergistic effect, promoting the dissociation of water molecules to generate oxygen during electrolysis while resisting the erosion of acidic media. The three-dimensional conductive network of the carbon nanotube support accelerates electron transport and reduces interfacial reaction impedance. The layered structure of the enhanced proton exchange membrane effectively blocks sulfate ion permeation, and its internal cross-linked polymer segments maintain dimensional stability in a concentrated acid environment, avoiding catalyst layer stripping due to membrane swelling. When hydrogen containing trace amounts of acidic gas is introduced into the anode of the electrolyzer, the catalyst surface with high iridium content preferentially adsorbs sulfides from the impurity gas, converting them into soluble substances through oxidation and expelling them from the system, thereby improving the purity of the hydrogen.

[0024] The reinjection module includes an acidic liquid buffer tank and a metering pump, with the reinjection point located in the positive electrode circulation pipeline; The execution logic of the injection module includes three levels of control: Feedforward control calculates the theoretical reinjection volume based on the hydrogen evolution rate. The calculation formula is as follows: Among them, the reinjection coefficient The range of values ​​is , Theoretical reinjection volume, The hydrogen production rate; Feedback control adjusts the metering pump frequency based on the pH sensor deviation; Safety limit: the amount of electrolyte injected in a single injection is ≤ 0.1% of the total electrolyte volume.

[0025] Feedforward control refers to calculating the theoretical reinjection rate based on real-time data of the hydrogen evolution rate, and establishing a correlation between the hydrogen evolution rate and the theoretical reinjection rate. The stoichiometric relationship of consumption determines the reinjection baseline. Feedback control refers to dynamically adjusting the metering pump frequency based on the deviation between the pH sensor reading and the target value. The feedforward control module generates the theoretical reinjection amount based on the product of the hydrogen generation rate and the reinjection coefficient, where the reinjection coefficient is used to compensate for reaction efficiency deviations, ensuring that the theoretical reinjection amount is consistent with... Loss matching. The feedback control module collects the deviation signal from the pH sensor in real time and performs closed-loop correction of the reinjection volume by adjusting the metering pump frequency, eliminating acid-base imbalance caused by electrolyte temperature fluctuations or impurities. The safety limiting module performs threshold verification on the theoretical reinjection volume before each reinjection operation. When the calculated value exceeds 0.1% of the total electrolyte volume, it forcibly limits it to the upper limit value to avoid system risks caused by sensor failure or algorithm anomalies. The three-level control forms a collaborative mechanism of feedforward rapid response to main disturbances, feedback to eliminate residual deviations, and limiting to ensure safe operation.

[0026] The hydrogen resource regeneration unit also includes a hydrogen circulation pipeline and an inert gas discharge valve. The hydrogen circulation pipeline returns the cathode output to the anode inlet of the electrolytic cell, and the inert gas discharge valve opens every 24 hours to release 0.3-0.7% of the volume of gas.

[0027] The hydrogen circulation pipeline refers to the closed loop connecting the cathode outlet and anode inlet of the electrolyzer, which can be implemented using 316L stainless steel pipe. Hydrogen generated at the circulating cathode is channeled to the anode to participate in the electrolysis reaction. The inert gas discharge valve is an automatic control valve located at the top of the storage tank, which maintains system pressure balance by periodically discharging trace amounts of gas.

[0028] Hydrogen generated at the cathode of the electrolyzer returns to the anode inlet via a circulation pipeline, forming a closed-loop system. This allows unreacted hydrogen to re-participate in the electrolysis process, reducing resource waste caused by hydrogen emissions. Simultaneously, the circulation pipeline maintains the hydrogen concentration on the anode side, preventing a decrease in electrolysis efficiency due to insufficient hydrogen. An inert gas vent valve opens according to a preset cycle to release impurities such as nitrogen accumulated during hydrogen circulation, preventing excessive inert gas concentrations that could lead to decreased hydrogen purity or explosion risks. The venting volume ratio is controlled at 0.3-0.7%, effectively removing impurities while minimizing effective hydrogen loss, thus improving hydrogen collection and purification efficiency and reducing emissions compared to traditional catalytic combustion methods. Secondly, it eliminates the need for external acid addition and extends the electrolyte replacement cycle.

[0029] When the system detects a low hydrogen evolution rate, the flow channel switches to a cross-dispersion mode. The electrolyte flow path is divided into multiple parallel branches, increasing the flow cross-sectional area and reducing the average flow velocity, thereby prolonging the contact time between the electrolyte and the electrode. This mode promotes... The reduction reaction proceeds fully by reducing the hydrogen ion concentration gradient, thus suppressing the continued occurrence of hydrogen evolution side reactions. When the hydrogen evolution rate exceeds a set threshold, the flow channel switches to a funnel-mouth concentration mode. The significant increase in inlet flow velocity creates a turbulence effect, forcibly stripping hydrogen bubbles attached to the electrode surface. At the same time, the negative pressure difference generated by expanding the flow channel cross-section accelerates the migration of bubbles towards the outlet, preventing gas resistance from affecting electrolyte circulation.

[0030] The dual-mode flow channel can switch between a cross-distributed flow channel and a funnel-mouth concentrated flow channel; the switching response time of the dual-mode flow channel is ≤150ms, and the opening cone angle of the funnel-mouth flow channel is... When the hydrogen evolution rate is less than or equal to 0.2 L / h, the dual-mode flow channel switching operation switches to a cross-dispersion flow channel, and the residence time of the electrolyte in the flow channel is extended by 1.2-1.5 times. When the hydrogen evolution rate is greater than 0.2 L / h, switch to a funnel-shaped centralized flow channel, and increase the inlet flow velocity of the flow channel to 1.8-2.2 times the original flow velocity to quickly remove hydrogen.

[0031] During charging and discharging, when the hydrogen evolution rate exceeds a set threshold, the dual-mode flow channel rapidly switches to a funnel-shaped concentrated flow channel mode via an electromagnetic drive mechanism. The switching response time is controlled within 150 milliseconds to prevent hydrogen accumulation in the flow channel due to delay. The opening cone angle of the funnel-shaped flow channel has been optimized through simulation to guide the electrolyte to form a stable turbulent state, enhance the shearing and breaking effect of hydrogen bubbles, and reduce flow resistance, allowing hydrogen to be directionally discharged along the concentrated flow channel. When the system detects a decrease in the hydrogen evolution rate, the flow channel automatically switches back to the cross-dispersion mode, extending the electrolyte residence time to improve reaction efficiency. This effectively solves the problem of low hydrogen discharge efficiency caused by the switching delay of the dual-mode flow channel, and improves hydrogen separation capability by optimizing the funnel-shaped flow channel structure. In energy storage scenarios with frequent charging and discharging, this technology can quickly respond to changes in the hydrogen evolution rate, reduce the risk of hydrogen retention, and improve system operational stability and energy efficiency.

[0032] Specifically, during system operation, the hydrogen collection module continuously collects the moist hydrogen generated by the fuel cell stack. After the liquid water is removed by the condenser and demister, residual impurity gases are separated by the palladium membrane purifier. The purified hydrogen is introduced into the anode of the PEM electrolyzer, where it undergoes an electrolytic reaction with deionized water introduced into the cathode to generate... Ions form an acidic solution temporarily stored in a buffer tank. When a charge / discharge stop signal is detected, the co-control unit immediately switches the flow channel to a funnel shape and pauses the reinjection operation, utilizing the negative pressure effect generated by the flow channel expansion to accelerate the discharge of residual hydrogen. After the flow rate fluctuations stabilize, the metering pump is started to inject the regenerated acidic solution in pulse mode, while the static mixer is activated to promote uniform mixing of the electrolyte. The charge / discharge controller adjusts the current output according to the real-time hydrogen evolution rate. When abnormal hydrogen evolution is detected, the charging current intensity is automatically reduced. At the same time, the dual-mode flow channel switches the flow channel shape according to a preset threshold to ensure dynamic matching between hydrogen removal efficiency and electrolyte reaction requirements.

[0033] The cooperative control unit is configured to perform the following: when charging / discharging stops, activate the horn-mouth flow channel and pause it. Reinject for 200ms; once the flow stabilizes, initiate pulsed injection. Refill and activate the static mixer; Dynamically allocate electrolytic cell power according to the formula: ,in This refers to the output power of the electrolytic cell. The correlation coefficient for hydrogen generation rate ranges from 1.5 to 2.2. The hydrogen production rate, The correlation coefficient for pH changes ranges from 40 to 60. This represents the change in the pH value of the solution.

[0034] The hydrogen evolution rate signal is collected in real time by a sensor. After filtering to remove noise, it is compared with the hydrogen evolution rate threshold preset by the system. When the hydrogen evolution rate exceeds the threshold, the exponential decay algorithm is triggered.

[0035] Based on the negative exponential correlation between hydrogen evolution rate and charging current, the charging current decreases exponentially as the hydrogen evolution rate increases, thereby suppressing the aggravation of hydrogen evolution side reactions. During the discharge process, the algorithm continuously monitors the load current. When the load current is lower than a certain percentage of the rated current, it automatically marks the surplus power of the current system and allocates the surplus power to the electrolyzer for use through energy scheduling logic, thereby realizing dynamic optimization of energy scheduling and forming a closed-loop suppression mechanism between hydrogen evolution rate and charging / discharging current.

[0036] When charging and discharging stops, the coordinated control unit activates the horn-mouth flow channel with a time gradient of 100ms-150ms and simultaneously pauses reinjection for 200ms±10ms. Once the flow rate fluctuation in the positive electrode circulation pipeline is ≤5%, pulsed reinjection is initiated with a reinjection frequency of 0.8Hz-1.5Hz and a pulse width of 80ms-150ms. Simultaneously, the static mixer is activated, and the mixer speed and reinjection flow rate satisfy the following: ,in For rotational speed, To ensure sufficient mixing between the reinjected liquid and the electrolyte, the control unit dynamically allocates the electrolyzer power according to a specific formula, taking into account both the hydrogen generation rate and the change in solution pH, thereby achieving precise control of the electrolyzer power and ensuring efficient and stable system operation.

[0037] The system also includes a safety protection module, which comprises: an overpressure protection unit, an overtemperature protection unit, and a low liquid level protection unit; The overpressure protection unit automatically opens the inert gas discharge valve to relieve pressure when the pressure in the gas phase space of the storage tank exceeds 0.8 MPa. The over-temperature protection unit cuts off the power supply to the electrolytic cell and activates water cooling when the temperature of the micro PEM electrolytic cell exceeds 90°C. The low liquid protection unit triggers an audible and visual alarm and suspends refilling when the acidic liquid buffer tank level is less than 10%.

[0038] The overpressure protection unit monitors the pressure of the gas phase space in the storage tank in real time through a pressure sensor. When the pressure exceeds the system's set threshold, it automatically triggers the inert gas discharge valve to open and release pressure, while simultaneously reducing the charging current of the fuel cell stack to prevent the pressure from continuously rising and causing safety risks. The overtemperature protection unit monitors the operating temperature of the micro PEM electrolyzer in real time through a temperature sensor. When the temperature exceeds the system's set value, it immediately cuts off the power supply to the electrolyzer and starts the water cooling system to remove excess heat through circulating cooling water, ensuring that the operating temperature of the electrolyzer is maintained within a safe range. The low-liquid protection unit monitors the liquid level of the acid buffer tank in real time through a liquid level sensor. When the liquid level is lower than the system's set level, it immediately triggers an audible and visual alarm to alert the operator, while automatically suspending the acid reinjection operation to prevent the metering pump from running dry and being damaged, and to avoid system malfunctions due to low liquid levels.

[0039] The technical scope of this invention is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this invention, and all such modifications and variations should fall within the protection scope of this invention.

Claims

1. A flow battery energy storage system for iron-chromium redox batteries, characterized in that, include: The hydrogen resource recycling unit includes: a hydrogen collection module, which connects the positive electrode exhaust port of the fuel cell stack to the gas phase space of the storage tank, and has a built-in condenser and demister and a palladium membrane purifier. The micro PEM electrolyzer has its anode inlet connected to the purified hydrogen outlet and its cathode inlet connected to a deionized water source. The reinjection module includes an acidic liquid buffer tank and a metering pump, with the reinjection point located in the positive electrode circulation pipeline; The hydrogen evolution dynamic suppression unit includes: a charge / discharge regulator that reduces the charging current or marks excess power in response to the hydrogen evolution rate signal; and a dual-mode flow channel that can switch between a cross-dispersive flow channel and a bell-mouth concentrated flow channel. The cooperative control unit is configured to perform the following: when charging / discharging stops, activate the horn-mouth flow channel and pause it. Reinject for 200ms; once the flow stabilizes, initiate pulsed injection. Refill and activate the static mixer; Dynamically allocate electrolytic cell power according to the formula: in This refers to the output power of the electrolytic cell. The correlation coefficient for hydrogen generation rate ranges from 1.5 to 2.

2. The hydrogen production rate, The correlation coefficient for pH changes ranges from 40 to 60. This represents the change in the pH value of the solution.

2. The iron-chromium redox flow battery energy storage system according to claim 1, characterized in that: The hydrogen resource regeneration unit also includes: a hydrogen circulation pipeline that outputs the cathode. Returned to the anode inlet of the electrolytic cell; The inert gas discharge valve opens every 24 hours to release 0.3-0.7% of the gas volume.

3. The iron-chromium redox flow battery energy storage system according to claim 1, characterized in that: The switching response time of the dual-mode flow channel is ≤150ms, and the opening cone angle of the horn-mouth flow channel is... .

4. The iron-chromium redox flow battery energy storage system according to claim 1, characterized in that: The anode catalyst of the PEM electrolyzer is composed of platinum, iridium, and a carbon support, with an iridium content ≥20wt%, and the membrane electrode is resistant to... Concentration ≥ 3%.

5. The iron-chromium redox flow battery energy storage system according to claim 1, characterized in that: The The execution logic of the injection module includes three levels of control: Feedforward control calculates the theoretical reinjection volume based on the hydrogen evolution rate. The calculation formula is as follows: Among them, the reinjection coefficient The range of values ​​is , Theoretical reinjection volume, The hydrogen production rate; Feedback control adjusts the metering pump frequency based on the pH sensor deviation; Safety limit: the amount of electrolyte injected in a single injection is ≤ 0.1% of the total electrolyte volume.

6. The iron-chromium redox flow battery energy storage system according to claim 1, characterized in that: When charging and discharging stops, the coordinated control unit activates the horn-mouth flow channel with a time gradient of 100ms-150ms and simultaneously pauses reinjection for 200ms±10ms. Once the flow rate fluctuation in the positive electrode circulation pipeline is ≤5%, pulsed reinjection is initiated with a reinjection frequency of 0.8Hz-1.5Hz and a pulse width of 80ms-150ms. Simultaneously, the static mixer is activated, and the mixer speed and reinjection flow rate satisfy the following: ,in For rotational speed, This is for the reinjection flow.

7. The iron-chromium redox flow battery energy storage system according to claim 1, characterized in that: The hydrogen collection module removes water vapor from the hydrogen through the condenser demister and purifies it through a palladium membrane purifier. The purified hydrogen is then introduced into the anode of a micro PEM electrolyzer, while deionized water is introduced into the cathode. The electrolysis current density is controlled between 1A / cm² and 3A / cm².

8. The iron-chromium redox flow battery energy storage system according to claim 1, characterized in that: When the hydrogen evolution rate is less than or equal to 0.2 L / h, the dual-mode flow channel switching operation switches to a cross-dispersed flow channel, extending the residence time of the electrolyte in the flow channel by 1.2-1.5 times; when the hydrogen evolution rate is greater than 0.2 L / h, it switches to a funnel-mouth concentrated flow channel, increasing the inlet flow velocity to 1.8-2.2 times the original flow velocity to quickly remove hydrogen.

9. The iron-chromium redox flow battery energy storage system according to claim 1, characterized in that: The formula for adjusting the charging current based on the hydrogen evolution rate signal is as follows: ,in The adjusted charging current, This is the initial charging current. This is the attenuation coefficient, with a value ranging from 0.02 to 0.

08. The hydrogen production rate is represented by .

10. The iron-chromium redox flow battery energy storage system according to claim 1, characterized in that: The system also includes a safety protection module, which comprises: an overpressure protection unit, an overtemperature protection unit, and a low liquid level protection unit; The overpressure protection unit automatically opens the inert gas discharge valve to relieve pressure when the pressure in the gas phase space of the storage tank is greater than 0.8 MPa. The over-temperature protection unit cuts off the power supply to the electrolytic cell and activates water cooling when the temperature of the micro PEM electrolytic cell exceeds 90°C. The low liquid protection unit triggers an audible and visual alarm and suspends refilling when the acidic liquid buffer tank level is less than 10%.

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